ANNUAL REPORT

OF THE

DIRECTOR

BUREAU OF STANDARDS

TO THE

SECRETARY OF COMMERCE

FOR THE

FISCAL YEAR ENDED JUNE 30, 1919

(Mucellaneous Publications—No. 40)

WASHINGTON

GOVERNMENT^PRINTING OFFICE

1919

ANNUAL REPORT

OF THE

DIRECTOR

BUREAU OF STANDARDS

TO THE

SECRETARY OF COMMERCE

FOR THE

FISCAL YEAR ENDED JUNE 30, 1919

(Miscellaneous Publications—No. 40)

WASHINGTON

GOVERNMENT PRINTING OFFICE

1919
Persons on a regular mailing list of the Department of Commerce should

give prompt notice to the " Division of Publications, Department of Commerce,

Washington, D. C," of any change of address, stating specifically the fiprm of address in which the publication has previously been received, as well as the new address. The Department should also be advised promptly when a publication is no longer desired.

2
CONTENTS.

Page. Chart showing functions of Bureau facing 17

I. Functions, organization, and location 17

1. Definition of standards 17 Standards of measurement 17

Physical constants 17 Standards of quality 17 Standards of performance 19 Standards of practice 20

2. Relation of the Bureau's work to the public 20 Comparison of standards of scientific and educational in- stitutions or of the public with those of the Bureau 20 Work of the Bureau in an advisory capacity 21

3. Relation of the Bureau's work to the industries 21

Assistance in establishing exact standards of measure- ment needed in industries 21 Performance of tests and investigations and collection of fundamental data 22 Training of experts in various industrial fields 22

4. Relation of the Bureau's work to the Government-- 23 Comparison of standards of other Government depart- ments with those of the Bureau 23 Performance of tests and investigations and the collection of scientific data of a fundamental nature 23 Advisory and consulting capacity 24 The Bureau as a testing laboratory, and its work in the preparation of specifications on which to base the pur- chase of materials 24

5. Relation of the Bureau to the military services during the war- Aid in the development of devices for military purposes 25 Development of new materials 26

Activities in the field of aeronautics 26

Activities in the field of metallurgy 27

Activities in the field of electricity 27

Activities in the field of chemistry 27 Development of optical glass and optical instruments 28

Organizations with which the Bureau cooperated during

the war 28

6. Organization 28

7. Location 30

II. Scientific and technical divisions 31

1. Weights and measures 31 Length 31 Paint films 31

Oscillograph films 32 Meter and yard bars 32

Sieves 32 Routine testing 33 Mass 33 A publication on weights 33 Advice 34 Cooperation with the War Department and others 34 Work with the Bureau of Markets on the problem of grading of wheat 34

Effect of brittle lacquer in rendering weights unre- Uable 34

Unsatisfactory weights 34

Effect of variations in humidity on sensitive balance 34

3
4 CONTENTS.

II. Scientific and tecliuical divisions—Continued.

1. Weights and measures—Continued.

Mass—Continued. Page. Clianges in tlie precision weighing laboratory 35 Routine testing of weiglits 35 Testing of balances 3.5 Visitors 35

Capacitj' and density 35 Gauge work 36 Scope of work 36 Appropriation and allotments 36 Gauge testing 37 Branch laboratories 37 Development and manufacture of precision end gauges. 37 Gauge storage and distribution 37 Gauge salvage and manufacture 38

Instruction courses 38 Design and construction of apparatus 38 Research 38 Reports on communications 39 Program . 39 Time-measuring devices 39 Gas measurement 40

Testing of town-border natural gas meters 40 Meters tested in the laboratory 40

Investigation of claims of tide motor 40

Consultation 40

Publications 41

Orifice-meter investigation 41 Photographic method of detecting camouflage 41 Thermal expansion 41 Researches 41 New expansion furnace 42

Publications 42 Commercial scales 42

Mine-scale investigation 42 Railroad track-scale investigation 43

Inspection and test of other weighing and measuring

apparatus 44

Standardization of large test weights 44

Specifications for the manufacture and installation of

railroad track scales for ordinary weighing 45

Specifications for scales for weighing grain 45 Weights and measures laws and administration 46

Cooperation with States and other interests 46 Proposed Federal legislation 47 Twelfth annual conference on weights and measures 47 Routine testing 50

2. Electricity 51 Scope of the electrical work 51

Special military work in electrical subjects 52

Standardization of electrical equipment and supplies for the War Department 52 Standards of resistance 53 Nondestructive tests of welds 53 Control of airplane guns 53

Action of Browning field gun 54 Inductance and capacity 54 Inductance and capacity laboratory 54 Gun firing investigations 55 Timing device 56 Submarine-mine investigation 57 Hydraulic machine gun S5'nchronizing gear for air- plane 57

Special muzzle-velocity measurements 57 Study of recent scientific development in France and

England 57
CONTEjSTTS. 5

II. Scientific and technical divisions—Continued.

2. Electricity—Continued. Page. Electrical measui'ing instruments 58 Testing of electrical instruments 58

Electrical tests of gasoline engine ignition systems 58

Electrical ti-ucks and tractors 58 Turret fire-control apparatus 59

Blasting caps 59 Radio generators 59 Cooperation with the American Institute of Electrical Engineers 59 New apparatus for electrical instrument testing 59

Ignition of cotton by electric .sparks 60 Magnetic measurements 60 General magnetic measurements 60 Magnetic analysis 60 Magnetic compasses 61 Photometry and illuminating engineering 61

Militai-y searchlight investigation 61 Photometric and illumination, investigations for mili- tary departments 62

Standardization of screens for measurement of bright- ness of radioactive materials 63

Inspection and life tests of incandescent lamps 63

Illumination surveys of Commerce Department build- ings 64 Radio communication 64 Development of radio work of Bureau 64

Electron tubes 65

Coil aerials 66

Signaling system for airplane landing 66 Submarine radio communication 67

Insulating materials 67 Radio measurements 68 Radio textbook 68 Sound ranging 69 Electrochemistry 69 Dry cells 69 Storage batteries 71 Railway signal batteries 72

Radioactivity and X-ray measurements 72 Luminous materials 72 Standard radium solution 73 Radium emanation work 73 Gamma-ray measurements of radium 74 X-rays 74

Public utility standards 75

Public utility investigations 75

Relation of Bureau to municipalities and public service commissions 76 Gas engineering 77 Standards for gas service 77 Indiana gas-standards investigation 77

Investigation of gas plant at Annapolis, Md 78

Gas-service inspection 78

Gas-appliance laboratory investigations 79 Coking of Illinois coal 79 Experimental retort test of Orient coal 80 Proposed national gas-safety code 81

Electi'ic service standards 81 Standards for electric service 81 Standards for street-lighting service 82 Standards for heating service 83 Telephone service 83

Telephone-service standards 84

Te.sting of telephone circuits and apparatus 84

Standardization of telephone terms 84
6 OONTEKTS.

II. Scientific and teclmical divisions—Continued.

2. Electricity—Continued. Page. Electrolysis prevention , 84

Electrolysis problem among public utilities 8-4 Economic importance of electrolysis problem 85 Inconvenience and hazard due to electrolysis 8.j Current work on electrolysis mitigation and related problems 86

Electrolysis surveys 86

Investigation of corrosion of cables in St. Louis 87 Improved methods for making electrolysis sur^^eys 87 Experimental work on electrolytic corrosion of lead 88

Safety engineering and safety standards 88

National Electrical Safety Code 88 Engineering and experimental work In connection with

the safety code 90

National Electrical Safety Code in practical use 90

Industrial safety standards 91

3. Heat and thermometi-y 92 •Thermometer, pyrometer, and heat tests 92

Publications 92 Information furnished 94

Outside relations 94 Thermometry 95

Clinical thermometers 95

Tolerances for laboratory thermometers 95 Airplane thermometers ; 96

Standardization of the sulphur boiling plant 96

Standardized solidification test 96 Thermometer comparator 97 High temperatures 97

Investigation in electronics 97

Melting points of chemical elements and other stand- ard temperatures 97 General pyrometry 98 Thermoelectric pyrometry 98 Radiation and optical pyrometry 98 Recording pyrometry 98 High-temperature control 98 Melting point of refractories 99 Heat treatment of glass 99 Temperature measurements in rotary Portland-cement

kilns 99 Coke-oven investigation 99 The high-temperature scale 100 Standard samples for thermometric fixed points 100 Heat measurements 100 Standard heat samples for use in calorimetiT 100

Properties of methane 101 Calorimeter envelope or containing vessel for conserving the heat of a calorimetric system at low temperatures 101 An experimental study of methods for measuring specific heat of gases 102

Properties of ammonia 102 High-pressure gauges 102 Gouy thermoregulator 102 Captive balloons 103

Special heat tests 103 Thermodynamics 103

Efflux of gases through small orifices 103 Hydraulics , 103 Dimensional methods as applied to physical problems. 10.3 Heat transfers 103 Low temperatures 104 Operation of plant 104

Liquefaction of hydrogen 104
CONTENTS. 7

II. Scientific and teciinical divisions—Continued.

3. Heat and thermometrj-—Continued.

Low temperatures—Continued. Page. Air liqueflers 104 Methane investigation 104

Fire resistance of materials and fire prevention 104

Fire-resistive properties of structural materials 104

Fire tests of building columns 105

Strength of metals at high temperatures 106 Pyrometer lag 107

Fire tests of concrete columns 107

Fire prevention 108 Automotive power plants and the fuels and lubricants therefor 109

Ignition; ; 109 Radiators 110

Altitude laboratory 110 Flame propagation in a gas-engine cylinder 111 Pressure cycles occurring in gasoline engines 111

Carbulretion 111

Effect of water injection on gas-engine performance 111 Tests of special engines and accessories 112 Petroleum conservation 112 Fuel comparisons, fuel savers, and kerosene-burning devices 112 Lubrication 112

Lubrication of internal-combustion engines 113

Standardization of instruments 113

Friction machine 113 Routine physical and chemical tests 113

4. Light and optical instruments 114 Spectroscopy 114 Red and infra-red spectra of chemical elements 114

Applications to astrophysics 114

Spectroscopic analyses 114 False spectra produced by gratings 115 Low-pressure tubes for spectroscopy 115

Spectroscopic and optical apparatus 115

Aerial photography 115

Hypersensitizing commercial panchromatic plates 118 Dyes for photographic sensitizing 118 Polarimetry 119 The rare sugars . 119 Production of d-Mannite 120 A new fixed point on the high-temperature scale 120 Natural rotation of quartz at high temperature 120 Adjustment and standardization of polariscopes 121 Testing of quartz control plates 122 Evaluation of the Clerget constant 122

Solubility of sugar and the causes of molasses formation 128 Proposed change in the normal sugar weight 123 One hundred-degree point of the saccharimeter scale_ 123 Tested supplies for United States customs laboratories 128 Customs laboratory at Boston 124

Supervision of customs laboratory of the Treasury

. Department 124 Pure sugars for miscellaneous purposes 124 Sugar and molasses at southern ports 125 Standard samples 125

Polarimeti-ic testing 125

Polarimetric tests of raw sugar 125

Testing of molasses 125

Filtration of sugar solutions 125 Beet molasses 126

Color of sugars and sirups 126
8 CONTENTS.

II. Scientific and technical divisions—Continued.

4. Light and optical instruments—Continued.

Polariiuetry—Continued. ^ Page. Standardization of methods of sugar manufacture 126 Molasses density 126

Definitions and specifications of commercial sugars 126 Colorlmetry_ 127 Present status of the color standards investigation 127 Extension and improvement of spectro-photometric

methods 128 Development of technologic methods for commercial

color grading of materials 129

Standardization of colorimetric nomenclature 131 Data on the spectral transmission of various glasses

in the visible and ultra-violet 132

Investigation of railway signal glasses 133

Investigation of eye-protective glasses 133

Precision determination of spectral transmission of

visibility solution 134

Calibration of " MunseU color standards " 134 New radiation formula 135

Colorimetric and related tests 135 Information furnished on color, colorimetry, and re- lated subjects : 135

Military investigations 135

Ultra-violet signaling 136

Visual detection of submarines 136

Chromatically concealed insignia and detection of chromatic camouflage 136

Publications 137

Optical and photographic methods for the detection of invisible writing 138 A method for color grading of red signal flares 138

Searchlight investigation 138

Optical instruments 141

Effect of strise on optical glass 141 Refractometer design 141

Circular letter on methods of silvering glass 141 Camera for photographing inside of machine-gun

barrel 141

Night-firing device 142 Condenser system 142

Calculation and removal of certain errors in centered systems of lenses 142

Testing of optical systems 142

Binoculars 143 Determining constants of optical glass 144

Tests of instruments 144

; Radiometry 145

Radionietry 145

Some optical and photo-electric properties of molybdenite 145

Spectral photo-electric sensitivity of silver sulphide

and other substances 146 Thermo radiophonic signaling devices 146

Ultra-violet signaling 146

Reflecting power of stellite and lacquered silver 147

Protection of moving-picture films fi'om heat of lamp_ 147 Exclusion of ultra-violet light from buildings 147

Information furnished on radiometric Subjects—

Conferences 147

Publications on radiometry 147

Interferometry 148 Thermal expansion of small samples 148 Dimensional changes of dental materials 148

Standardization of precision gauges 148

Dispersoids 149

Properties of smoke 149
CONTENTS. 9

II. Scientific and teclmical divisions—Continued. Fage.

5. Chemistry 14U Chemical testing 149 Chemical publications 150

Physical chemistry 151

Refrigeration materials and problems 151

Purification of materials for special purposes 151

Critical solution temperature work 152

Atlas of heterogeneous equilibria 158 Electrochemistry 153

Electroplating 153

Metallurgical chemistry 155 Gas chemistry 155

Balloon fabrics 155 Automatic gas analysis apparatus 157

Miscellaneous problems 158 Reagents and apparatus 158 Chemical reagents 158 Platinum 159 Platinum substitutes 159

Miscellaneous tests 160

Analytical methods and standard samples 160 Standard analyzed samples 160 Determination of tungsten, molybdenum, zirconium,

. and uranium in ores and metallurgical products 160

Miscellaneous researches 1 160

Lubricating oils, rubber, paper, textiles, ink, and glue 161

Airplane dopes 161 Chemistry of leather 161 Chemistry of rubber 161 ChemistiT of textiles and commercial dyes 161 Pure dyes 161 Camouflage 161 Photographic sensitizers 162 Chemistry of inks 162

Printing inks 163

Printers' rollers 163

Glue, mucilage, paste 163

Miscellaneous - 163 Examination of material for the Steamboat-Inspection

Service 164

Metals, Cement, and Bituminous materials 164 Chemical work on metals and alloys 164

Protective metallic coatings 164 _ Bituminous materials 165 Coatings for concrete ships 16'6 Marine glue 166 Linoleum cement 166 Oakum 167

Separation of benzol, toluol, and xylol 167 Cement 167 Miscellaneous tests 167

Paint, varnish, and soap 167 Paint specifications 167

Protective coatings for ordnance stores 168

Tests of water resistance of enamels and varnishes 169

Fireproofing fiber board 169 Carbon tetrachloride fire extinguishing liquid 169 Soap 169 Linseed oil 170

Miscellaneous 170

6. Engineering research and testing 170 Mechanical appliances 170

Fire-extinguisher investigations and tests 170 Comparative test of roof ventilators 171 Thermostatic valves for vacuum heating systems 171

Miscellaneous tests of mechanical appliances and

equipment 172
10 coxte:s^ts.

II. Scientific and technical (ii^-lsions—Continued.

6. Engineering researcli and testing—Continued. Pag«. Engineering instruments 172 Water-current naeter-rating station 172

Calibration of engineering instruments 172 Theory of measuring instruments 172 Aeronautic instruments 174 Fundamental theoretical work 174 Development of standard testing equipment 174

Construction and performance specifications 175 Researches on the errors of instruments 175

Flight tests on airplane instruments 175 Instrument collection 176

Salvage methods 176 Study of European instruments and methods of test- ing 176 Instrument instruction for aviation officers 177 Experimental development work 177

Testing of aeronautic instruments 178

Technical information circulars 179 Correspondence and conferences 179 Cooperation with American manufacturers 180 Cooperation with American Physical Society 180 Cooperation with National Advisory Committee for Aeronautics 180 Future development of the aeronautic instntoents

work 180 Aerodynamics 181 Wind tunnel investigations 181

Physical oceanographic instruments 182

7. Structural, miscellaneous, and engineering materials 182 Metals 182

Variable camber airplane wing 182

Test of 150-ton floating crane for the Navy 183

Tests of motor-truck wheels 184

Tests of electric welds 184 Tensiometer 186

Investigation of wire rope 187 Oxyacetylene 188 Machetes 188

Brinell hardness table 188

Piston rods 188

Nonscatterable glass 188 Metal airplane construction 189

Semisteel shells 189 Bronze 190

Calibration of testing machines 190

Circulars of information 190

Publications 191 Moving laboratorv to new quarters in Industrial Building 191 Summary of tests 192 Equipment 194 Cement, concrete, stone, gravel, and sand 195 New branch laboratories 196 Routine inspection and testing of cement 196 Development of testing methods 197 Design of concrete mixtures 199 Fineness investigation 200 Volume changes in mortars and concretes 201 Concrete oil storage__ 202 Waterproofing concrete c 203

Stucco 203

Durability of concrete in alkali soils and waters 204 New material for increasing the rate of hardening

of cement 204

Acceleration of hardening of concrete by steam 201
CONTENTS. 11

II. Scientific and tecliaical divisions—Continued.

7. Structural, miscellaneous, and engineering materials—Con. Cement, concrete, stone, gravel, and sand—Continued. Page. Automatic freezing and thawing apparatus 205

Investigation of building stones 205

Service tests on floors and concrete floor treatments— 205 Reinforced concrete investigations 206

Miscellaneous concrete investigations and tests 210

Tests of cement for governmental purposes 214 Soundness of Portland cement 214 Magnesia content of Portland cement 215 Magnesium oxychloride (Sorel) cements 215

Concrete columns with cast-iron cores 216

Lime, gypsum, etc 216

Cooperation with lime manufacturers 216 Compressive strength of cement-lime mortars 217

Effect of addition of hydrated lime upon properties

of concrete 217 Carson plumb-bob test 217

Possible causes of unsoundness of lime plasters 217 Measurement of plasticity 217 Standard sand 218

Reinforced gypsum : . 218

Factors influencing time of set of gypsum 218

Increasing the strength of gypsum and making it waterproof 218 Measurement of properties of commercial gypsum 219

Effect of gradation of sand on properties of sand- lime brick 219 Factors influencing the bond between mortar and

sand-lime brick 219

Effect of duration of hardening on properties of sand- lime brick 219 Routine and miscellaneous work 220 Rubber 220 Rubber analysis 220

Balloon fabrics 221 Rubber tires 221

Assistance to manufacturers of tires 221 Power loss in automobile tires 222 Rubber packings 222

Hospital supplies 222

Tests of fire hose for Government departments 222 Rubber jar rings for canning 222

Miscellaneous rubber goods 222 Future work in rubber 223 Leather 224

Sole leather 224 Harness and strap leather 225 Upper leather 225

Miscellaneous 226 Development of specifications 226 Routine testing 226 Experimental tannery 226 Laboratory facilities 227

Textiles 227

Identification of fibers 227 German uniform fabrics 227 Ramie felts 227

Airplane and balloon fabrics 228

Sealskins ' 228

Miscellaneous identifications 228 Oakum specifications 228 Chemical retting of flax 228 Cotton goods 229 Waterproofed canvas 229
12 CONTENTS.

II. Scientitic and technical divisions—Continued.

7. Structural, miscellaneous, and engineering materials—Con.

Textiles—Continued. Page. Woolen goods : 229

Commercial dyeing practice 229 American dyes 230

Dyemaking 230

Mordants 230

Mercerization 230

Flax packing 230

Sizing 230

Camouflage 231 Routine testing 231

Airplane fabrics 231 Tautness , 231

Penetration of dope correlated with tear resistance— 232

Balloon fabrics 232

Satins 232 Banana-plant fiber 232

Tests of baseballs 232 Experimental textile manufacturing equipment 232 Cotton 233 Woolen and felt- 233 Paper 233 Routine testing 234

Paper-testing methods 234 Paper-making fibers 235

Felts used on paper machines 235

Utilization of waste cotton linters 235 Paper bags for lime and cement 236 Use of lime and limestone in the paper industry 236 Unbleached pulp for papers 237

Filtering paper for gas masks 237

Military uses of wall and plaster board 237

Miscellaneous information furnished public and pri- vate interests 238

8. Metallurgy 238 General activities 238 Cooperation with societies and boards 238

Exhibits of war activities 239 Committee on nonferrous alloys 240 Conferences 240

Publications in metallurgy 240

Metallurgical test-s 241 Work for the Ordnance Department of the Army 241

Testing 242 Correspondence 242 Problems of military interest 243 Research aid to manufacturers 247 Manufacture of collapsible tin tubes 247 Annealing of hard cold-worked nickel brass 247

Copper-lead bearing metal 247

Deterioration of zinc-aluminum die-casting alloys 248

Sterling silverware 248 Sharpness standards 248

Miscroscopy and structure 248

Protective metallic coatings for rustprooflng iron and

steel 248

Nickel spark-plug electrodes 248 Cements for spark-plug electrodes 249

Special steels - 249

Corrosion of nonferrous alloys 249 Study of " deep etching " of metals 249

Microstructure of .pure iron and mild steel at high

temperatures 249 "Flaky steel" 250 Pearlite in steel 250 Welding research 250
COKTEK'TS. 18

II. Scientific and technical divisions—Contiiuied.

8. Metallurgy—Continued.

Heat treatment and thermal analysis ^-j" New method for thermal analysis -^j

• Iron-carbon transformers ^j?}

Magnetic and density tests j"^

Mechanical properties Tensile properties at high temperatures

High-speed steels 252 Gauge steels ^5;}

Metal diaphragms j^j' Embrittling of steel by cleaning, pickling, and plating. 253 Temperature measurements in steel works 254

Physical properties and miscellaneous metals 254 Tin conservation 254 Bearing metals 254

Corrosion of brass under tension 254

Strength of solder and soldered joints 255 Gold palladium alloys as substitutes for platinum___ 255

Fusible-tin boiler plugs and tin alloys 255

Storage-battery grid alloys 255

Acid-resisting alloys 255

Effect of degree of reduction upon internal stresses

set up during cold rolling 256

Solidification of steel ingots 256 Working of metal.s . 256 Treatment of pure nickel .' 256

Light aluminum alloys 256

Railroad materials 256

Graphitization of white cast iron 257

Investigation of chilled-iron car-wheel stresses 257

Packing-ring inve.stigation 257

Ingot investigation 257

Effect of sulphur and phosphorus in steel for rail- road materials 258 Chemical metallurgy 258

Alloys and pure metals 259 Pure aluminum 259

Tests of "Phillips' alloy" 259 Method for determining gases in steel 260 Determination of individual gases 260

Conservation of manganese 260

Blecti-olytic carbon method 261

Ladle-test ingot investigation 261

Alloy work 261 Work on gases in metals 261 Work on investigating of the deoxldation of steel 261 Production of pure aluminum 261 Foundry : 261 Government bronze and its substitutes 262 New melting equipment 262 Weathering of art bronzes 263

Efficiency study of electric furnaces 263

Several types of metallurgical refractories 263

Protective coatings for aluminiim castings 263 Experimental and practical ca.stings 263

Investigation of light aluminum casting alloys 263 Molding sand investigations 264 New type of volumeter 264

9. Ceramics 265 Clay products 265 Standardized clay tests 265

Refractories 265

Light-weight refractories 265

Refractory porcelain 266

Sillimanite refractories 266
14 CONTENTS.

II. Scientific and teclmical divisions—Continued.

9. Ceramics—Continued.

Clay products—Continued. Page. American crucible and glass-pot clays 266

Porcelain glass pots •- 266

Casting process 266

Study of spark-plug porcelains 266 Use of American clays in white-ware pottery 267

Terra-cotta bodies and clays 267

Hard-fire porcelain 267

Clay tests 268

Scientific and industrial cooperation 268

Equipment of ceramic division 268

Enameled-metal products 268

Zircite refractories 268

Zinc spinel 268

Tennessee ball clays 268

Investigation of brick piers 268

Investigation of the strength of hollow-tile walls 269

Architectural terra cotta 270

Fire tests of concrete columns 270 Determination of laws of earth resistance 270

General tests of structural materials 271

Glass 272

Colored glasses 273

Washington glass plant 27S

III. The Office 1 274

1. General 274

Organization 274

Space 274

Staff 275

2. Sections 275

Finance 275

Funds and disbursements 275

Staff 275

Office system 276

Appropriation statements 276

Summary of tests 277

Personnel > 279

Present personnel 279

Effect of war and armistice on the personnel 279

Personnel changes 279

Personnel records 280

Anniial and sick leave 280

Eligibles 280

Employees in military service 280

Additional work 280

Publications 281

Publications issued during the year 281

Scientific papers 281

Technologic papers 281

Circulars 282

Miscellaneous 282

Distribution 282

List of publications 282

Property and stores 282

Equipment 282

Perpetual inventory records 282

Technical supplies 282

Additional space needed 283

Mail 288

Fifing system 283 New equipment 283

Subject filing , 283

Filing equipment 283

Personnel 283
CONTENTS. 15

III. The Office—Coiitiuued.

2. Sections—Continued. Page. Library 284

Accessioned volumes 284

Teclinical journals 284

Circulation 284

Additional space 284

Dispatch 285 Shipping 285 Quarters 285 Purchase 285

Requisitions and orders 285 Records 285 Bids 285 Space and assistance 285 Catalogue library 285 Copying 286

Information 286

Progi-ess-of-work records 286

Distribution of technical information 286

Technical news bulletin 287

Miscellaneous information service 287

IV. Engineering and construction 288

1. Power plant, buildings and grounds, and transportation 288

Operation and maintenance of mechanical plant 288 Transportation 289

Construction and repair 289

Buildings and grounds 290

2. Photographic laboratory 291 Sensitometer 291 Developer testing 291 Photographing the mail 291 General photography 291

V. Recommendations 292

Salaries 292 Power plant 292 Remodeling building for mechanical plant 292

Additional land 292 Care of buildings and grounds 293

Test-car depot 293


NATIONAL BUREAU OF STANDARDS

Washington, D. C.

1919

FUNCTIONS

Development, construction, custody, and maintenance

of reference and working

STANDARDS

and their intercomparison, improvement, and application

in science, engineering, industry, and commerce.

142289—COM 1919. (To face page 17.)
REPORT

OF THE DIRECTOR, BUREAU OF STANDARDS.

Department of Commerce,

BuEEAtj OF Standards,

Washington, July 1, 1919.

Sir: There is submitted herewith a report of the work of the

Bureau of Standards for the fiscal year ended June 30, 1919.

I. FUNCTIONS, ORGANIZATION, AND LOCATION.

Before describing- in detail the various scientific and technical

problems in which the Bureau of Standards is engaged, the following brief statement as to its functions and organization may be

helpful to those unfamiliar with the subject of standardization in

its broad and modern sense. The standards with which the Bureau is authorized to deal may

be conveniently classed as follows: Standards of measurement,

standard values of constants, standards of qualitj^, standards of

mechanical performance, and standards of practice.

I. DEFINITION OF STANDARDS.

Standards of Measurement.

'A standard of length may be taken as an example of a standard

of measurement. It must be a length which is unchanging, reproducible, and capable of being compared with the working standards

used in the most precise scientific work or with those used in commerce and industry. The fundamental standard must be subdivided

and working standards prepared of these parts, and for the meas- urement of greater length standards must be prepared which are multiples of the fundamental standard. This process of subdividing

and multiplying the standard involves difficulties as great as those

met with in the preparation of the fundamental standard itself. The construction of a set of standard weights from a single unit

is also an illustration; a whole set of standard weights must be

prepared before the standard weight of the Government can be- come available to the public. When the standard of length or weight

has been found with as many desirable qualities as possible, and

before the working standards of the subdivisions or multiples can

142289—19 2 17
NATIONAL BUREAU OF STANDARDS

Washington, D. C. 1919

FUNCTIONS

Development, construction, custody, and maintenance

of reference and working

STANDARDS

and their intercomparison, improvement, and application

in science, engineering, industry, and commerce.

H^^iSO—COM lUlll. (T>i finf 17.)

STANDARDS PURPOSE

1 STANDARDS OF MEASUREMENTReference and working standards for measurements of all kinds, including fundamental and derived STANDARDS OF MEASUREMENT for expressing

the quantitative aspects of space, time, matter, energy, motion, and of their

interrelations. By definition, specification, or material standard, covering, for example, length, area,

aild volume; maas, weight, density, and pressure; heat, light, electricity, and radioactivity, including quantity, flux, inteniity, density, etc.

STANDARD CONSTANTSNatural standards or the measured numerical data as to materials and energy, known as physical or STANDARD CONSTANTS, i. e., the fixed points or

quantities which underlie scientific research and industrial processes when, scientifically organized. Mechanical equivalent of heat, light, and electricity and of gravitation; specific densities; viscobitica; melting and boiling points; heat capacity; heats of combustion; velocity

of propagation of light; conductivities of materials to heat and light; electrochemical and atomic weights and many similar magnitudes determined experimentally with maxi- mum precision and referred to fundamental standards of measure.

To aid ACCURACY IN INDUSTRY through uniform and correct measures; To ASSIST COMMERCE IN SIZE STANDARDIZATION of containers and products; To PROMOTE JUSTICE IN DAILY TRADE through systematic inspection and regulation; To facilitate PRECISION IN SCIENCE and TECHNOLOGIC RESEARCH

through calibration of units, measures, and instruments involved.

To SERVE as an EXACT BASIS for scientific study, experiment, computation and design; To FURNISH an EFFICIENT CONTROL for industrial processes

reproducible and uniformly high quality in output; To SECURE UNIFORMITY OF PRACTICE in graduating measuring instru- ments, compiling tables, in standards of quality and performance, and wherevei uniformity is desirable; To AID LABORATORY RESEARCH BY REDUCING ERRORS and uncer. tainty caused by use of data of doubtful accuracy.

securing

STANDARDS OF QUALITY

Specifications for material (by description, sample, or both), known as STANDARDS OF QUALITY, fixing in measurable terms a property or group

of properties which determine the quality. The numerical magnitude of each constituent property pertinen' and specific magnitude in units of measure of such significant fai position, form, structure, and others.

the quality involved, as uniformity, comTo secure HIGH UTILITY in the PRODUCTS of industry by setting an attainable standard of quality; To furnish a SCIENTIFIC BASIS for FAIR DEALING to avoid disputes or settle differences; To PROMOTE TRUTHFUL BRANDING and ADVERTISING by suitable standards and methods of test; To PROMOTE PRECISION and AVOID WASTE in science and industry by affording quality standards by which materials may be made, sold, and tested.

STANDARDS OF PERFORMANCE

Specification of operative cfTiciency or action, for machines and devices, STANDARDS OF PERKORIWANCE, specifying the factors involved in terms

susceptible of measurement.

Numerical statement of speed, uniformity, output, economy, durability, and other factors which tosetber define the net efficiency of an appliance or machine.

STANDARDS OF PRACTICE

Codes and regulations impartially analyzed and formulated after study and

experiment into STANDARDS OF PRACTICE for technical regulation of construction, installation, operation, and based upon standards of measurement,

quality, and performance.

Collation of standard data, numerical magnitudes, and ranees of the pertinent factors dcBniog Quality, safety, economy, convenience, and ciBciency.

[ To CLARIFY THE UNDERSTANDING between maker, seller, buyer, and user, as to operative eiSciency of appliances and machines; To make EXACT KNOWLEDGE THE BASIS OF the buyer's choice- To STIMULATE AND MEASURE MECHANICAL PROGRESS

To FURNISH for each utility a single IMPERSONAL STANDARD of practice as a BASIS FOR AGREEMENT of all interests clearly defined in measurable terms

To INSURE EFFECTIVE DESIGN and INSTALLATION of utilities of all Kinds; To PROMOTE SAFETY, EFFICIENCY, and CONVENIENCE in the main- tenance and OPERATION of such utilities- eIfECTtI^^^JII'"'"'' °^ PRACTICE where such is practicable, and EFFECTIVE ALTERNATES in other cases.


REPORT

OF THE DIRECTOR, BUREAU OF STANDARDS.

Department op Commerce,

Bureau of Standards,

Washington, July 1, 1919.

Sir: There is submitted herewith a report of the work of the

Bureau of Standards for the fiscal year ended June 30, 1919.

I. FUNCTIONS, ORGANIZATION, AND LOCATION.

Before describing in detail the various scientific and technical

problems in which the Bureau of Standards is engaged, the following brief statement as to its functions and organization may be

helpful to those unfamiliar with the subject of standardization in

its broad and modern sense. The standards with which the Bureau is authorized to deal may

be conveniently classed as follows: Standards of measurement,

standard values of constants, standards of quality, standards of

mechanical performance, and standards of practice.

I. DEFINITION OF STANDARDS.

Standards of Measurement.

-A standard of length may be taken as an example of a standard

of measurement. It must be a length which is unchanging, reproducible, and capable of being compared with the working standards

used in the most precise scientific work or with those used in commerce and industry. The fundamental standard must be subdivided

and working standards prepared of these parts, and for the meas- urement of greater length standards must be prepared which are multiples of the fimdamental standard. This process of subdividing

and multiplying the standard involves difficulties as great as those

met with in the preparation of the fundamental standard itself. The construction of a set of standard weights from a single unit

is also an illustration; a whole set of standard weights must be

prepared before the standard weight of the Government can be- come available to the public. When the standard of length or weight

has been found with as many desirable qualities as possible, and

before the working standards of the subdivisions or multiples can

142289—19 2 17
18 EEPOKT OF DIRECTOR OF BUREAU OF STANDARDS.

be prepared, the question as to the method of compai"ison arises,

Avhich again involves the solution of difficult scientific problems in

connection with the balance or the methods used. These balances

range from that capable of measuring the thousandth part of a milligram to the large testing machine capable of measuring a load

of thousands of tons. The complete range must be covered which

involves not only a lai-ge number of working standards, all of which

must agree with the fimdamental standard, but apparatus suitable

for the comparison of these standards with all of the lengths or weights found in practice.

These steps and equipment are absolutely essential in order to

secure uniform measurements of length or weight throughout the

country, and they have their counterpart in every quantity that has

to be measured, whether it be length, weight, temperature, heat, light, or the various electrical measurements or other standards of measurement. These standards in one form or another are involved in

practically every scientific investigation, industrial process, en- gineering structure, or commerical transaction.

Physical Constants.

There are many fixed relations between physical quantities, the

values of which it is extremely important to know. These values are usually termed " physical constants," and are used in every branch

of scientific work or industry. The amount of heat required to change a pound of water into steam under normal conditions and the

relation between heat and mechanical energy are two important

physical constants; their values -are used in practically every computation in connection with the designing of steam engines and boilers,

the tests of their efficiencies, or the measurement of their output.

The amount of heat required to turn liquid ammonia into vapor or

the amount of heat required to melt a pound of ice are constants

equally important in the refrigerating industries. The value of the

relation between electrical and mechanical energy is involved in many

commercial transactions concerned in electricity.

Accurate and authoritative values of these constants are just as

essential as in the case of standards of measurement. Many of these

now in use are old and obsolete and need redetermination by means

of the best modern facilities for physical measurement. Their determination involves the most difficult and precise work in all branches

of physics and chemistry—a fact not generally known by those not

engaged in the scientific or technical work where these constants are

used.

Standards of Quality.

A standard of quality for a given material may sometimes take the

form of a sample of that material with which other materials of the same kind can be compared, but this is generally a makeshift of the

poorest sort. It is only resorted to in the absence of definite and

reliable specifications in terms of measurable properties; that is to

say, a standard of quality of a material usually takes the form of a

specification or definition of its properties, involving, of course, the

measurement of those properties by means of the usual standards of

measurement. A certain kind of steel, a cement, a paint, an oil, or a paper or cloth is found by use to be good or poor. The questions
REPORT OF DIRECTOR OE BUREAU OE STANDARDS. 19

then arise : Why is it good or poor ? What are the physical or chemical properties or the particular combination of elements which make

it of good or poor quality ? How are its properties to be measured or

its constituents determined ? These are questions for the laboratory

to answer and involve physical and chemical investigations of the

most difficult sort. A standard of quality for a given material necessarily takes into

account the purpose for which the material is to be used. To set the

standard too low results in losses, poor efficiency, and even loss of

life ; to make it too high may result precisely in the same thing ; that

is to say, the material must be suitable for the purpose intended, and

the Bureau's investigations in connection with the properties of

materials are to enable the user of these materials, first, to select in- telligently the material best suited for the purpose ; second, to specify

it in terms which the producer can not mistake ; and, third, to make

the necessary tests to ascertain whether or not the material supplied

iS in accordance with the specifications.

The actual testing of materials by the Bureau of Standards to as- certain whether or not they comply with specifications is confined

almost exclusively to Government purchases, but in making these

tests (in which the Bureau has had the hearty cooperation of practically all the departments of the Government service) it is compelled

to make many investigations concerning the properties of materials,

their specification, and measurement. While this work is of great

value in placing Government pui-chases on a correct business basis,

the results of the investigations as to the properties of materials and

the information gained in testing Government supplies are even more important to the general public and are distributed in the form

of suitable publications.

The Bureaii does not compete with private testing laboratories,

but endeavors to assist them by the development of standard si^eci- fications, methods of measurement, and other matters where unifoi'mity is desirable, much of which information, as stated above, is secured in connection with the testing of materials purchased by the

Government and a close observation of their use. The time is not far distant when it Avill be required that all materials bouglit or sold shall be as represented, but it should be kept

in mind that this is impossible except in the case of those materials

where proper standards of quality and methods of measurement have

been developed. It must not be assumed that the purchaser or user

is the party principally benefited in the development of such standards; on the contrary, the manufacturer, first of all, is interested in

the quality of all things which atfect the quality of his product; and

while the Bureaii's efforts in this field are devoted principally to the

pointing out and measurement of those properties upon which tiie quality of the materials depends, it is to be regretted that its force

and equipment are insufficient to render more assistance to manufacturers with a view to a direct improvement of those parts of the

pi"ocess upon which the quality of the output depends.

Standards of Performance.

The value of an instrument, device, or machine almost always depends upon the efficiency of its performance. In such cases it is necessary to state the performance desired or guaranteed in terms
20 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

which are correct and susceptible of measurement. As in the case of standards of quality, the standard involved is more often in the

form of a specification, but specifications are useless unless based

upon correct scientific and mechanical principles and supplemented

with a statement of the method to be used in ascertaining whether

or not the specifications or guaranties have been complied with.

The performance of an engine or boiler, a pump, an electrical

generator or motor, a weighing device, or a telescope can usually be

measured, but the quantities to be measured and the method used

must be specified correctly and understood by all the parties con- cerned in the construction, purchase, or use of such apparatus. To

do this properly involves the use of standards of measurement, standard values of constants, and standards of quality. The Bureau of

Standards does not attempt to cover this field completely, but only

those cases where there is a lack of definite information upon whicli

to base specifications and only to the more important classes of apparatus. To secure this information involves investigations quite as scientific in character and as difficult as in the case of other

standards, as well as a knowledge of technical and manufacturing

processes. In this field, as well as in the field dealing with the

properties of materials, the Bureau has had the most hearty cooperation of the various Government experts, manufacturers, engineers,

and the technical societies. Standards of Practice.

Standards of practice are generally involved in the enactment of

laws when technical and scientific matters are concerned, in the or- dinances relating to the regulation of public utilities, and in the es- tablishment of building and safety codes. Like standards of per- formance, they are dependent upon standards of measurement and

standards of quality and are of the most vital importance in questions pertaining to the welfare and safety of the public. In a field so broad the Bureau can only touch upon the more important aspects

of the work, where national uniformity is desired—fields which can

not be covered efficiently in private laboratories.

2. RELATION OF THE BUREAU'S WORK TO THE PUBLIC.

Comparison of Standards of Scientific and Educational Institutions or of the Public with Those of the Bureau.

It is perfectly obvious, even to one unfamiliar Avith the subject,

that the maintenance on the part of the Government of correct standards of measurement or quality or performance calls for continuous

scientific and technical investigations of the highest grade, involving

the most competent expert services and the best scientific equipment.

When this is accomplished, there still remains the serious problem of

making the results available and useful to the public.

The Bureau compares with its own standards of measurement the

standards of measuring instruments of States, cities, scientific laboratories, educational institutions, or the public, for which a nominal fee

is charged, except in the case of the National and State Government

institutions. It gives advice concerning these standards or their use, whether it be in connection with the enactment of laws, regulations, or ordinances concerning the weights and measures of everyday
KEPOET OF DIKECTOK OF BUREAU OF STAisDAKDS. 21

trade or in connection with precision standards used in scientific Avork. It gives advice upon request to State and city officials, publicservice commissions, and public-utilitj^ corj)orations regarding the

standards of measurement, or quality, or performance involved in

legislation or regulation pertaining to the public utilities. Work of the Bureau in an Advisory Capacity.

Man}- questions of disagreement between the public and utility

companies as to matters involving the use of standards are referred

to the Bureau for advice or adjustment, often avoiding unfair and

inconsistent regulations, as well as long-drawn-out and expensive liti- gation. There is a great need on the part of the public for unbiased

and reliable information pertaining to the standards entering into

the regulation and sale of the services of public utilities. As far as

possible, such information is given in the form of publications upon

definite subjects.

The Bureau is constantly called upon to compare the weights and

measures in use by State and municipal officials, as well as by the

public in general, with those belonging to the Bureau. This work is of the greatest importance in bringing to the attention of the public

the value of exact standards and the benefits derived through their use in ordinary life. Likewise, a great many inquiries are received concerning the use of the various materials of construction, and the Bureau has fre- quently assisted in the preparation of specifications on which to base

the jDurchase of such materials.

In the formulation of safety codes designed to govern electrical

and other construction, the Bureau has taken an active part and has

been represented on many committees dealing with such work.

3. RELATION OF THE BUREAU'S WORK TO THE

INDUSTRIES.

Assistance in Establishing Exact Standards of Measurement Needed

in Industries.

It must not be inferred from the above that the Bureau's activities are devoted principally to the interests of the user or consumer. The fundamental facts regarding standards of measurement, quality, or performance are the very things which most deeply concern manufacturers : they are fundamentally concerned, either directly or indii-ectly, with the improvement of methods of iDroduction or the cjualit}' of the output. It may be said that the Bureau occupies some- what the same position with respect to the manufacturing interests

of this country that the bureaus of the Department of AgTiculture do

to the agricultural interests. Many industries ai'e just beginning to

realize the importance of precise methods of measurement and scientific investigation which, in practically every case, involve some

kind of measurement.

It is upon quality as well as upon price that competition must

finally depend, whether in domestic or foreign commerce. The use

of exact methods and scientific results is the greatest factor in .the improvement of quality, efficiency, or the development of new in- dustries. The educational value of the Bureau's work in this re- spect is i^lmost entirely unknown to the general public, and yet the
22 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Buieaii I'eceives liuiuireds of letters, as vv^ell as many personal visits from manufacturers, seeking information as to standards of measurement, how to use them, how to measure the properties of materials, or

as to the fundamental pliysical and chemical principles involved;

also, what is of even greater importance, how to initiate and carry

out scienlific investigations and tests on their own account in their

particular fields of work.

The importance of maint^iiniug pcientific institutions having to do with standardization and the application of precise measurements

to the industries has been recognized by all the leading countries of

the world. Great Britain maintains the Standards Department of

the Board of Trade, which is in charge of the standards and inspection service of the trade weights and measures; also the National

Physical Laboratory, whose, functions include matters pertaining to

scientific and technical standards, physical constants, and to some

extent the properties of materials. The Laboratoire d'Essais of

France, while not as extensive as the English institution, is charged

with similar duties. Germany maintains three such institutions

the Normal-Eichungs Kommission, equipped with the buildings,

personnel, and apparatus necessary in standardizing and controlling

the weights ancl measures of trade; the Physikalisch-Technische

Ileichsanstalt, covering testing and investigations in connection with

scientific and technical standards other than Aveights and measures; and the Prussian Government maintains the Materialpriifungsamt,

a large institution devoted to the investigating and testing of structui-al, engineering, ancl other materials.

It is generally recognized that these institutions have been ex- ceedingly important factors in the industrial progress of these

countries.

Performance of Tests and Investigations and Collection of Fundamental Data.

While the greater part of the Bureau's efforts were given up during the war to work in connection with the military departments of

the Government, it was neveT before called upon to such an extent

for advice and scientific data by the industries. Most of these questions arose out of the manufacture of equipment and material of a military nature, as a large number of firms entered into this work

during the war without any great amount of previous experience.

A great many of these requests came directly from the manufacturers, others through the War Industries' Board, and still others

from various commissions having to do with the production and

commercial asjDects of the war. Every section of the Bureau cooperated to a greater or lesser extent with the manufacturers of the country, and, as a result, closer

relations have been established between the industrial plants and

the Bureau. It is evident that this relationship will continue and

become of great economic value; but, if the Bureau is to retain its high position in the various industrial fields and meet the rapidly

increasing demands for its services, the greatest amount of support

possible must be given to it by the industries.

Training of Experts in Various Industrial Fields.

Through the increased activities of nearly all the industries of the

country and the demand for trained investigators, the Bureau's
EEPOET OF DIRECTOR OF BTJKEATJ OF STANDARDS. 23

scientific staff iias been largeh' depleted^ and it will be a matter of some time before it can be brought back to the plane of high effi- ciency which it has previously maintained. It is assumed that the

compensation paid scientific and technical men in the GoTernment

service will be adjusted to a scale more commensurate with that ]Daid

by scientific institutions and industrial laboratories, but even then

the industries should cooperate in ever} Avay possible to maintain

the Bureau's staff intact and of the best material. Many instances

could be given where the industries have taken experts with little warning and with no apparent consideration as to the consequences.

The training of men for research is one of the most important ways

in which the Bureau can aid the industries ; but to do tliis it is neces- sary to maintain its own staff in the highest degree of efficiency.

4. RELATION OF THE BUREAU'S WORK TO THE

GOVERNMENT.

Comparison of Standards of Other Government Departments with

Those of the Bureau.

The use of exact standards enters into every branch of the Government service, as it does into every industry and into the everyday life of all persons. It was in the Government service, however, that the

need for exact standards was first aDpreciated. The work done for

the Government is in nowise different from that carried on for individuals and involves the same problems.

Many bureaus of the Government service are charged with the

administration of laws and the establishment of regulations, the in- telligent application of which depends very largely on. the use of

exact standards. This is true to a greater extent than is generally

supposed. The Bureau of Standards has cooperated freely with such

branches of the Government, and the service rendered has involved

every department of physics and chemistry co\ ered by the Bureau's

activities. The neglect of such matters in the past has been a frequent

source of misunderstanding and litigation between the Government

service and the public. Conspicuous examples of bureaus to which

such assistance has been given are the Customs and Internal-Revenue

Services, Steamboat-Inspection and Coast Guard Services, and the

Bureau of Navigation of the Department of Commerce, as well as

all bureaus of the War and Xavy Departments engaged in construction or development work.

Performance of Tests and Investigations and the Collection of Scientific Data of a Fundamental Nature.

The engineering and building construction in progress at all times

by the Government is exceedingly great, both in variety and magnitude, in all of it a knowledge of the materials employed is of fundamental impoitance from the standpoints of economy, efficiency, and

safety. The work of investigating the properties of structural materials was taken up and is carried on primarily for the purpose of

securing the information needed by the Government service in its structural work. This information is as necessary to the public in

construction work, and eA'ery effort is made by the Bureau to make its findings in a form available to the public generally. The demands
24 REPORT OF DIRECTOR OE BUREAU OF STANDARDS.

for information of this sort have come from practically all Government bureaus and establishments, but especially so in connection with

the structural work carried on by the Office of the Supervising Architect, the engineering branches of the Army, the Bureau of Construction and Repair of the Navy, the Panama Canal, and the Reclamation

Service.

A\dvisory and Consulting Capacity.

One of the most important services which the Bureau has been

able to render to other departments of the Government, both civil and military, has been of an advisory and consulting nature in matters pertaining to the scientific work in which these departments were interested. Too great emphasis can not be placed on the importance of this phase of the Bureau's work. Its maintenance would

be warranted for this reason alone, even though its usefulness in this

field is but a small portion of the total service which it has rendered

other branches of the Government.

The Bureau's laboratories have been open and its experts available

at all times to every department of the Government, and in many

cases substantial help has been rendered to the military and civil departments through the familiarity of the Bureau with certain kinds

of work, and its ability to quickly decide whether the particular

methods, materials, or devices were suitable for the service in question. The Bureau as a Testing Laboratory and Its Work in the Preparation of Specifications on Which to Base the Purchase of

Materials.

The Bureau of Standards serves as a testing bureau for the various

departments of the Government when called upon; and, as such, is assisting to place Government purchases upon an economical and

businesslike basis. The example of the Government in such matters

has a far greater influence upon the public than is generally supposed. The Government can do no greater, service to the country

than to place its own purchases upon a basis which may be taken as

a standard by the public at large. This work involves the specification of a wide range of structural and miscellaneous materials and

their testing, when delivered, to ascertain whether or not they comply with the specifications. This is especially important, since such

materials are purchased by means of competitive bids, a method re- sulting in much fraud and injustice unless suitable standards are

established and successful bidders held absolutely to this standard in

making deliveries. Furthermore, most purchasing officers are realizing the great importance of having such testing done by a disinterested institution equipped with the scientific and other facilities for

performing the service in a manner that is fair to both parties con- cerned in the purchases.

Among the Government bureaus and establishments which have

utilized the Bureau of Standards as a testing institution in connection with the purchase of supplies, may be mentioned the Government

Printing Office, in connection with the purchase of paper, inks, and

printing supplies, and the Post Office Department, in connection

with the purchase of paper, twine, textiles, etc. A wide range of

materials has been tested for the Quartermaster Corps of the Army,
KEPOKT OF DIRECTOR OF BUREAU OF STANDARDS. 25

the Bureau of Supplies and Accounts of the Navy, and the Panama

Canal. The General Supply Committee has called upon the Bureau

for assistance in the specification of all sorts of supplies and equipment, as well as the testing of samples submitted by bidders of the

supplies bid upon. Practically every branch of the Government

service, including the District of Columbia, utilizes the Bureau of

Standards as a testing bureau. Here, again, as in other fields of the

Bureau's activities, it gains much useful knowledge, which is given

to the public in the form of suitable publications.

5. RELATION OF THE BUREAU TO THE MILITARY

SERVICES DURING THE WAR.

Aid in the Development of Devices for Military Purposes.

The war brought about the most rapid and intense application of

science the world has experienced. Scientific research received a stimulus that extended far beyond military fields and produced

results of great permanent value to the industrial, as well as the

military, world. The Bureau cooperated with the Army and Navy

in the solution of their scientific problems relating to the development of all sorts of devices for military purposes, and was frequently

called upon for advice by those manufacturers who during the war

entered the field of producing military equipment for the first time.

The experience gained through the investigation of these problems

had many useful applications in the fields of industry without in any

way revealing the military nature or value of the particular results sought.

The Bureau was exceedingly fortunate in securing substantial

r.ppropriations from Congress for carrying on work of this character in cooperation with the Army and Navy. The various bureaus

of both these departments not only devoted funds to scientific research wherever necessary, but their cooperation with the Bureau

of Standards was all that could be desired, and they should be given

the gi^eatest credit for utilizing the resources of the Bureau to their

fullest extent. Many cases might be cited where the Bureau undertook the development of military devices by its own staff or in cooperation with

the experts of the Army, Navy, or manufacturers. A few characteristic and important examples which ma}' be cited are : The development of sound-ranging devices in cooperation with the Engineer

Corps of the Army; the production of an electrical device for synchronizing airplane machine guns and propellers ; the application of

the radio compass to both air and water navigation ; the development

of instruments for the navigation of air craft ; the production of a hydrogen detector for submarines; and the development of all sorts of optical instruments for purposes of observation, range finding,

and navigation. Work in cooperation with the Inventions Section

of the General Staff has resulted in great improvements in the design

of rifles, machine guns, and many other devices for like use. An

elaborate investigation of methods of signaling by the use of invisible rays and the development of devices for the detection of secret writing may likewise be cited. In the field of aeronautic power
26 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

plants, a special carbureter for air-craft engines and a high-speed

gas-engine indicator were developed, together with other devices for

aviation use. A great deal of work was done in connection with

aerial photography for the Signal Corps, and, as a result of this

investigation, a special hypersensitized plate was produced.

Development of New Materials.

As mentioned in the preceding paragraph, the stimulus of the war

was felt in every branch of the industries. Not only were new devices produced for militarj^ purposes, but certain entirely new materials were developed. The shortage of raw materials in certain lines,

caused by the cutting off of the supply from Europe, led scientific men to turn their attention to the production of satisfactory substitutes, and to the use of many familiar materials for novel purposes. Thus the manufacture of optical glass in this country (a

material formerly produced only in Europe) was proven to be a commercial proposition through the elaborate investigation which

had been carried on by the Bureau even before the war. In like

]nanner the shortage of linen led the Bureau to develop a satisfactory cotton fabric for use in covering airplane wings. A filter paper

for gas masks was produced, and many specifications were prepared

for all sorts of materials, such as prepared roofings, wall board,

plaster board, cement, concrete, etc. New paints, designed for the

protection of the interior of shells, the holds of vessels, as well as waterproof glues and varnishes, were developed through the Bureau's

efforts. In all this work the Bureau cooperated with the military departments and the manufacturers, often acting merely in an advisory

capacity, but more frequently carrying out complete investigations

in each of the particular lines. Here, again, the information gained

in reference to materials for military work has even a greater value

in connection with the industries. There are few cases where the

military and industrial interests were not equally important.

Activities in the Field of Aeronautics.

The Bureau has engaged in researches and tests in connection with

the determination of important fundamental data needed in aero- nautics ; the investigation and test of instruments, devices, and materials used in air craft for the air services of the Army and Navy, the

National Advisory Committee for Aeronautics, the Bureau of Aircraft Production, and for manufacturers—a service which has re- sulted in great permanent value to both military and civil aero- nautics and to those employing internal combustion engines.

This work has included tests in the altitude laboratory on various

aeronautic engines to determine the variation of horsepower with

altitude, compression ratio, and air temperature; the value of supercharging devices designed to enable airplanes to attain higher alti- tudes ; the comparative values of various aviation fuels ; the preparation of specifications for special aviation gasoline; and the relative

merits of different carburetors, radiators, and other apparatus. A

complete investigation of airplane ignition systems, including tests of magnetos and spark plugs, the development of a special improved

spark-plug porcelain; investigation of the strength of materials

used in the construction of airplanes; tests of all kinds of aero- nautic instruments and de^'elopment of certain special devices; aero-
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 27

ilynainic tests of aerofoils and model airplanes; tests and the preparatioia of specifications for lubricating oils: tests of fabrics and air- plane wings, and the development of a satisfactory- cotton fabric

:

investigation of deAdces for sj^nchronizing machine-gun fire with air- plane propellers: study of self-luminous materials for use on the

dials of aeronautic instrmnents: routine tests and development of

special varnishes for airplanes.

Activities in the Field of Metallurgy.

In this field the Bureau has cooperated with the Army, Navy, the

National Advisory Committee for Aeronautics, and other military

bureaus. The work has covered a complete investigation of aluminum

alloys for use in the building of air-craft engines, etc., Government

bronzes, development of special steels, investigation and development

of satisfactory aluminum solders, and the preparation of specifications for bearing metals. A large amount of routine testing of gun

steel and similar work was carried on. Activities in the Field of Electricity.

In the field of electricity the Bureau has continued to do a great

deal of routine testing, including the acceptance tests of lamps and

other electrical appliances for the bureaus of the War and Navy

Departments. It has also carried on a number of complete investigations, among which may be mentioned the development of a satisfactory synchronizing device to be used in connection with machine

guns designed to fire between the blades of airplane propellers, tests of electric trucks and tractors, develoi^ment of radio apparatus, and a study of the fire-control system in battleships. A special manual has

been prepared for radio operators, and the possibilities for the improvement of means of insulating cable, such as those submerged in

salt water, have been investigated. Many such cases could be cited. Activities in the Field of Chemistry.

In cooperation with the Gas Defense Service, the Bureau tested a number of materials for the construction of gas masks and studied

the composition and effects of poison gases. A very large number of

routine analyses were carried out for the various branches of the

Army and Navy, these usually taking the form of acceptance tests of

materials.

Owing to the shortage of suitable dyes for use in manufacture of

Army uniforms, American manufacturers wexe early called upon to supply dyes from this countty. The Bureau carried out an investigation of textile dyes and aided in the preparation of suitable specifications to be useci in their purchase. It also assisted in the development of satisfactory methods for the testing of materials for Array

uniforms as to dye fastness and other chemical properties.

Other work included the development of special paints, enamels,

varnishes, and protective coatings and the preparation of specifications for the same. During the war a great number of buildings of a temporary character were erected, and, in connection with these, a very large quantity of prepared roofing was purchased. The Bureau

imclertook an investigation of this class of materials, and, as a result

of the work, was able to furnish to the organizations interested a

satisfactory specification for such roofing.
28 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Development of Optical Glass and Optical Instruments.

For a number of years the Bureau has carried on experimental

work with a view to assisting in the manufacture of optical glass in

this country. This has involved a rather complete investigation of

manufacturing processes and the making of a considerable amount

of glass in the Bureau's own shops, which was utilized for military

purposes. The information thus gained in regard to the pots used

and materials involved, the technique of the furnace, the molding,

annealing, testing, and inspection of glass was given freely to those

manufacturers who were engaged in the manufacture of optical glass

to supply the large and sudden demand for it in the construction of

military optical instruments. The Bureau's plant will be maintained on an experimental basis and should render valuable assistance

in the maintenance of the optical-glass industry in this country.

(The importance of this work was emphasized during the war, as the

foreign supply of this kind of glass was practically cut off.) The importance of optical instruments is, of course, recognized at

all times, but during the war the demand for suitable binoculars and

field glasses was unusually acute. The test of such instruments has

been carried on for the Army and Navy, and, in general, American

makers have turned out a very satisfactory product. The bureau has

cooperated in the specification, testing, and standardizing of the optical instruments used in military work.

An elaborate investigation was conducted on the use of ultra-violet

light for signaling purposes. By the use of a source of such light

and a suitable glass through which to view it a means of signaling,

invisible to the naked eye, was developed for the Signal Corps of the

Army and the Bureau of Steam Engineering of the Navy. Unusually rapid photographic plates for airplane cameras were investigated and a satisfactory panchromatic plate developed.

Organizations with Which the Bureau Cooperated During the War.

Civil organizations: Aircraft Board, Emergency Fleet Corporation, National Research Council, War Industries Board, National

Advisory Committee for Aeronautics, United States Railroad Administration, Bureau of War Risk Insurance, American Red Cross,

and others.

United States Army: Air Service, Coast Artillery CorjDS, Construction Division, Engineer Corps, Field Medical Supply Depot,

Inventions Section General Staff, Motor Transport Corps, Ordnance

Department ; Purchase, Storage, and Traffic Division ; Quartermaster

Corps, Signal Corps, and others. United States Navy : Bureau of Construction and Repair, Bureau

of Ordnance, Bureau of Steam Engineering, Bureau of Yards and

Docks, Hydrographic Office, Office of Naval Intelligence, various

navy yards and naval bases.

6. ORGANIZATION.

The organization of the bureau's scientific and technical staff is based upon the nature of the expert service involved rather than

upon the classes of standards. For example, the division of weights

and measures has to do with all matters pertaining to standards of
KEPORT OF DIRECTOR OF BUREAU OF STANDARDS. 29

length, mass (weight, as it is commonly termed), time, density, and

similar questions, whether they arise in connection with the precision

standards used in scientific investigation, the master standards of

manufacturers, or the ordinary weights and measures of trade. A

standard of quality or performance where any of the above meas- urements form the fundamental and most important factor would

be referred to this division.

The division of heat and thermometry has to do with heat standards, the testing of heat-measuring apparatus, the determination of

heat constants, of which there are many, and all investigations per- taining to quality or performance where heat measurement is the

essential and predominating factor. Similarly, the electrical division is concejmed with all the elec- trical problems that may be taken up at the bureau, whether in con- nection with the various electrical standards of measurement, elec- trical constants, the electrical properties of materials, or the performance of electrical equipment.

Questions in optics enter into standards of all kinds to a greater

extent than has been supposed; hence, there is an optical division

provided, with experts in spectroscopy, polarimetry (used in sugar

analysis), color measurement, the principles of optical instruments,

and the measurement of the optical properties of materials.

Practically all investigations concerning the various classes of

standards involve chemistry in one form or another. There are also

many chemical standards and questions which arise in connection

with chemical work generally, especially in the industries; hence,

there is a chemical division, cooperating with every other division

of the bureau, as well as taking care of the questions of a purely

chemical nature that come to the bureau and which fall within its functions.

In the case of the more important technical fields, divisions have

been formed dealing more specifically with large and important

classes of materials, hnt many of the purely scientific questions in- A'olved would be handled by one of the above-mentioned scientific divisions or jointly with it. The work of the technical divisions is just as scientific in character, but deals more specifically with manufactured products.

The work of the structural engineering and miscellaneous materials

division includes the inve.stigation, testing, and preparation of

specifications for these materials, such as the metals and their alloys,

stone, cement, concrete, lime, the clay products, paints, oils, paper,

textiles, rubber, and other miscellaneous materials.

The division of engineering research makes investigations and

tests regarding the performance and efficiency of such instruments,

devices, or macliinery as the Bureau may talfe up that do not fall directly under one of the scientific divisions. The division is a

small one, and its work is devoted almost exclusively to assistance

given other departments of the Government and the General Supply

Committee in designing, specifying, or testing equipment. It should in time form one of the more important branches of the

Bureau's work.

The questions pertaining to the manufacture, specifications, test- ing, and use of the metals and their alloys is so important that a
30 KEPOET OF DIRECTOR OP BUREAU OF STANDARDS.

division known as the metallurgical division was formed of the ex- perts engaged in these problems.

The employees engaged in clerical work, purchasing, files, records,

accounting, and library are knoAvn as the office division, while those

employed in the operation of the mechanical plant, the various shops,

•?nd the care of the buildings and grounds form the engineering and

construction division.

7. LOCATION.

The laboratories of the Bureau of Standards are located in the

northwest section of Washington, on Pierce Mill Road, near Connecticut Avenue, and are reached by the Chevy Chase car line. They were located outside of the business center of Washington in

order to insure freedom from mechanical, electrical, and other

disturbances common to the business and more thickly populated

sections of the city. Furthermore, the area of ground necessary precluded a site near the city. It has been found by experience that the

efficiency of the employees, especially those engaged in testing and

scientific investigation, has been greatly increased by the location

of the laboratories in a section free from the ordinary disturbances of

city life.
II. SCIENTIFIC AND TECHNICAL DIVISIONS.

I. WEIGHTS AND MEASURES.

[Length, area, volume, mass, density, pressure, and time, including researches on units and

standards, measuring methods and instruments, specifications and tolerances, and the standardization incident thereto for inspectors of weights and measures, manufacturers of measuring appliances, scientific and technical laboratories. Government bureaus, engineers, and

the general public]

LENGTH.

[The design, improvement, and investigation of length-measuring apparatus, calibra- tion and test of yard bars, meter bars, geodetic tapes, level rods, haemacjtometer apparatus, cement sieves, expansivity of solids.] The urgency of the testing work for the military departments

during the war led to the deterioration of the apparatus, which was

corrected as soon as the opportunity offered itself. The condition

of all of the comparators and standards was carefully studied, and

steps were taken to place them in first-class condition.

The desirability of controlling the temperature of the room in

the basement in which the meter comparator is installed has long

been recognized, but for the reasons mentioned little progress in

carrying out the plans had been made until the signing of the

armistice released some of the energies previously tied up. During

the year the interior of the room was insulated from the outer walls. Also a' regulating thermostat and heating and cooling coils were

either constructed in the shop or ordered from the manufacturers.

It is expected that arrangement will make it possible to control the

temperature in the room to within 0.5° centigrade. More perfect

control of the standards at any time under investigation will be

secured by placing them in insulated containers to protect them from

fluctuations of the room temperature, the main consideration usually

being; that the two standards under investigation shall be at the same known temperature.

Investigations have also been conducted to determine the best

method of illuminating the standards. The apparent shifting of

the lines on the standards when the prisms mounted under the

microscopes are moved Avas eliminated by placing a thin sheet of

xylonite, one surface of which has been slightly roughened, under

the prisms.

Paint Films.

Certain considerations have indicated that one element of proper

specifications for paint should probably be the thickness of a coat of it on a metal plat^ under certain specified conditions. In a study

of this subject by the chemistry division it Avas realized that in

order for measurements of this film thickness to be practical a simple device must be employed. To that end experiments were made

by this section which resulted in the conclusion that a dial gauge

31
32 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

could be employed, a rather stiff and plane metal plate being used

for the film of paint and measurements taken at various designated

points both before and after the paint had been applied. Three

points of support for the plate were suggested as preferable from

a number of considerations. With a special device of this character

the chemistry division has been continuing the investigation.

In a special test, fihns of the paint used on ordnance shells gave

a very consistent series of results. One of the specific points in view was to determine whether the film was sufficient for protection and

yet thin enough to insure that there would be no interference or rubbing when fired. Oscillograph Films.

An investigation of the accuracy with which oscillograph films

used in ballistic work could be measured b}- different methods indicated the best methods of measurement and the accuracy to be

expected. One of the singular facts, probably due in part to physiological and psychological causes, which was noted in this investigation, was that more accurate results seem to be obtained by moving

the cross hairs of a micrometer microscope until a line, ruled on the

object at the focus of the objective, is exactly between these cross

hairs, than to move the object slowly until the line appears to be be- tween the cross hairs. This would seem to have a rather wide range

of application to many measuring devices and possibly to other

instruments.

Meter and Yard Bars. The Canadian Government at Ottawa submitted one of their principal standards of length for a determination of the total length. As

it had at some time previous^ been tested at the National Physical

Laboratory in England, and, as a rather complete intercomparison

of several meters Ijelonging to this Bureau was made in connection

with the Bureau's test, it is believed that the final results may give

additional facts concerning the changes which may occur in a length

standard during the course of time.

Sieves.

Few articles tested by the Bureau have as wide a range of use as

sieves. Among the users may be mentioned the cement, fertilizer,

mining, metallurgical, abrasive, chemical, drug, and sugar industries. The attention of this section has been especially devoted to the finer-meshed sieves. In the case of 200-mesh sieves a very noticeable improvement in American-made cloth has been noted during this

last year. Because of the large amount of explosives used by the Government, and because of the need of rather strict specifications for the

ingredients, this Bureau rendered considerable assistance in giving

advice as to the proper specifications for the sieves and in settling

various disputes which arose from the fact that in many cases there

exist several distinct sieves of different make, all designated by the same mesh. In compliance with many urgent demands, the standard scale for testing sieves adopted in 1916 has been revised. In the

revised scale not only the size of the openings, but also the diameters

of the wires, form a regular and continuous sequence from the

coarser to the finer sieves. The ratio of openings is throughout,
KEPOKT OF DIRECTOR OF BUREAU OE STANDARDS. 33

and each sieve is designated by a number approximately equal to the

mesh per linear inch. This revised scale has been sent to those believed to be interested, and from the many favorable replies so far

received, its early adoption seems assured. Although primarily in- tended as a standard for testing sieves its application is by no means

thus limited, the rather strict tolerances being omitted or modified

when the sieve is to be used for general routine or commercial sieving.

Routine Testing.

The following is a list of articles tested by the length section

during the year, with the fees charged

:

Fee. 12 meter and yard bars $64. 00

575 hsemacytometers 930. 00

152 sieves 175.20

8 samples sieve cloth 11. 60

43 polariscope tubes 17. 60

6 viscosimeters 18. 00

27 level rods 76. 50

31 invar tapes 224. 50

128 metallic warp tapes 95. 25

114 steel tapes 97. 55

2 spring balances for tapes . 50

33 articles for contact measurements 54. 25

40 articles for line measurements 197. 00

8 articles for angular measurements 19. 50

3 Brinnel microscopes and 1 Ames dial 8. 00

42 miscellaneous articles for test 75. 00

10 miscellaneous articles for ruling 100. 00

Total (1,284 articles) 2,164.45

MASS.

(The comparison of precision weights with the standards of the Government, the preparation of specifications and tolerances for weights and balances, Improvement in design

of balances, solution of fundamental problems arising in connection with weighing, preci- sion weights, and balances.) A Publication on Weights.

The revised edition of Circular No. 3, "Design and Testing of

Standards of Mass," was published in December. Besides the new

regulations in regard to testing and fees, it contains detailed descriptions of the requirements _ as to structure and accuracy for the

classes of weights now recognized by the Bureau and the purposes

for which they are intended, also a considerable amount of information concerning air buoyancy and its effect on weighing, and a

fairly detailed description of the methods used in calibrating

weights, with forms for computing the corrections.' The circular

should be of use to anyone wishing to calibrate a set of weights

from a few certified standards, as well as to those using Bureau of

Standards' certified weights for very high accuracy weighing, and

142289—19 3
34 KEPORT OF DIEECTOR OF BUREAU OF STANDARDS.

to people wishing to buy or make high-grade weights for various

purposes.

Advice.

A considerable amount of advice and information about balances

and weights has been furnished orally or in writing to members of

the Bureau and to men fi'om other Government departments and

from private organizations.

Cooperation with the War Department and Others.

The section has cooperated with the War and Navy departments

by making considerable numbers of miscellaneous weighings for

them, including weighings of machine-gun parts, cartridges, etc., and by some loans. It has also aided other sections of the Bureau,

both by making weighings for them, including a series of weighings on specimens for the thermal-expansion laboratory, and by

lending balances and weights for occasional use. Work with the Bureau of Markets on the Problem of Grading Wheat.

The section has been cooperating with the inspection service of

the United States Bureau of Markets in improving a device for

determining the weight per bushel . of wheat from samples, as a

basis of grading it. Tn connection with this work four grain

testers have been tested for the United States Bureau of Markets

and one for the State of Kansas, and some improvements suggested

and adopted. A large number will probably be tested during the

coming year. Effect of Brittle Lacquer in Rendering Weights Unreliable.

That the loss of weight caused by brittle lacquer breaking off in

ordinary careful handling may be large enough to be serious for some kinds of chemical weighing was shown by a retest of three

sets of weights Avhich had been in use for a short time only in the

chemistry division of the Bureau. In several cases the loss was

over a milligram for a single weight, although there was little appreciable wear except on the neck of the knob where the tweezers

grip the weights.

Unsatisfactory Weights.

Much delay and extra work has been caused by rejections made

necessary by the inaccuracy of weights submitted for test. Most of

the class S sets have contained weights which were out of tolerance

when first submitted. This widespread inaccuracy and frequent

cases of unsatisfactory finish—slivers, inadequate plating, brittle

lacquer, etc.—are probably due in a large part to unsettled conditions caused by the war. The need of testing new weights is con- tinuously being shown by the discovery of poorly constructed or

seriously inaccurate weights.

Effect of Variations in Humidity on a Sensitive Balance.

An investigation of the irregular and unreliable behavior during

the spring and summer of a new assay balance (supplied by the

maker in place of the one mentioned last year, which had proved

unsatisfactory for the rapid testing of small analytical weights, for
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 35

which it was bought) disclosed the interesting fact that this balance

is highly sensitive to changes in atmospheric humidity. An ex- haustive study to determine the exact seat of the trouble has been

planned, but only a small part of it has been carried out as yet, owing

to the pressure of other work. The failure of this balance has more

than doubled the time required for testing the milligram weights of

each " analytical set," since it has been necessary to return to the

longer, methods of calibrating to secure the required accuracy.

Changes in the Precision Weighing Laboratory.

During the earlier part of the year the work was hampered by the

confusion incident to interchanging the weighing rooms. The time

spent in planning the details of the new weighing room resulted

in an arrangement at once more compact and more convenient than

the former one. Also temperature conditions are much more constant in the new room than in the old. Routine Testing of Weights.

The total number of weights tested during the year was 2,594, a decrease of about 5 per cent as compared with the year previous.

Of these about 51 per cent were for private parties—^mostly commercial companies—^25 per cent were for our own Bureau, 5 per cent

for the War and Navy Departments, 9 per cent for other branches

of the Federal Government, especially the Treasury and the Department of Agriculture, and about 5 per cent each were for the States

and for the educational institutions, respectively.

Testing of Balances.

The number of balances tested was unusually large—36 as against

22 last year. These were mostly for various divisions of this Bureau.

Visitors.

The growing interest of the general public in the work of the

Bureau is shown by the increasing number of visitors who have come to see the precision weighing laboratory and its work. A record

kept during several typical weeks in the spring shows that during

that season the average number of visitors per month was about 90. The amount of time required to show them the laboratory totaled more than three working days each month. This does not include

any of the large groups from schools which occasionally came

through, nor those who were attending the Physical Society meetings

or the Weights and Measures conference at the Bureau. During

the four days of the latter conference there were 53 visitors, taking

seven hours' time.

CAPACITY AND DENSITY.

(Design and improvement of apparatus and methods of test, preparation of specifica- tions for, and testing of glass volumetric apparatus, capacity measures and hydrometers, measurement of density and thermal expansion of liquids, density of solids.) During the year the following apparatus was tested as to compliance with the specifications promulgated by the Bureau

:
36 REPORT OF DIEECTOE OF BUREAU OF STANDARDS.

Apparatus. Nvunber

sub- mitted.

Tested. Passed. Fee.

Burettes 418

1,353 1,648

713

131

330

3 1,325

1,383 646

109

252 1361. 50

2. 15 1,153.20

52V. 65

218. 05

. 138. 45

Cylindrical graduates

1,076

1,021 459 Flasks

Pipettes transfer Pipettes measuring

Hydrometers

4,266 3,796 2,395.00

1,042

180

15156

1,023

180

10756

262

853 1, 165. 25 90.00

114.55

28.00 262.00

4,054.8a

Fifty-eight per cent of the volumetric apparatus submitted passed

the test of the Bureau, while of that actually tested 65 per cent

passed.

Of the hydrometers submitted for test, 82 per cent passed, while

of those actually tested 83 per cent passed the test of the Bureau.

GAUGE WORK.

(Improvement in the design and use of munition and other gauges, origin and develop- ment of methods of test, manufacture and salvage of gauges, examination and test of gauges.) The gauge section was organized as a part of the division of

weights and measures at the beginning of the war to provide facilities on a larger scale to inspect and certify limit gauges and precision-length standards and to assist in the solution of problems aris- ing in connection with gauge work.

The staff of the section numbered about 140 on July 1, 1918, and

had further increased to 225 in November of the same year. By

July 1, 1919, the nimiber had been gradually reduced to 55 members.

Scope of Work.

Besides the routine testing of gauges at the Bureau in Washingtion, the section during the past year conducted branch laboratories

developed and manufactured Hoke precision gauges; improved,

designed, and constructed gauge-testing apparatus; salvaged and

manufactured limit gau.ges ; stored, shipped, and conducted a clear- ing house for master gauges; conducted instruction forces for Government gauge inspectors; studied gauge and tolerance problems

for the National Screw Thread Commission; and prepared and distributed communications and reports regarding such parts of the

above work as are of general interest. Appropriation and Allotments.

The section carried on its work under an appropriation of $150,000

for gauge standardization. This was supplemented by allotments

totaling $233,000 made " to take care of expenses in connection with

the salvage and manufacture of master gauges for the inspection

Division, Ordnance Department." Another allotment of $50,000 was made by the Engineering Division of the Ordnance Department for

experimental work and manufacture of precision gauges.
EEPORT OF DIEEOTOR OF BUREAU OF STANDARDS. 37

Gauge Testing.

The number and lots of gauges submitted for test, month by

month, are shown in the following table, which includes the work at Washington and the three branches:

Date.

July, 1918 August 1918..., September, 1918 October, 1918... November, 1918 December, 1918. January, 1919...

Number

of lots.

413 523

521 478

218

Number

of gauges.

5,733

5,513 5,050

5,813 5,984

4,218

2,367

Date.

February, 1919 March, 1919...

April, 1919 May, 1919

Juiie, 1919

Total....

Number

of lots.

10289

86

79

51

3,708

Of the above gauges about 45 per cent were classified as screwthread, 45 per cent as plain, and 10 per cent as profile, fixture, and

miscellaneous types.

During the war the inspection was handled with such dispatch

that the average time between the date of arrival and completion

of tests and reshipment was from three to four days.

Branch Laboratories.

The three branch gauge-testing laboratories were located in New

York City; Cleveland, Ohio; and Bridgeport, Conn. Each was

equipped with facilities duplicating on a small scale the Washington laboratory. These branches served a large number of manufacturers in the industrial centers in which they were located and

aided materially gauge production by making it possible for manufacturers to send sample gauges and work by messenger for immediate inspection. All of the branch gauge laboratories have been

discontinued on account of the lack of funds.

Development and Manufacture of Precision-End Standards.

In July, 1918, experimental work was begun to demonstrate the

feasibility of mechanical production of precision-end gauges under

the direction of the inventor, W. E. Hoke, and in cooperation with

the Bureau's expei"ts in optical methods of measurement, which are

essential. (For details of this work, see report of the optical sec- tion.) An early set of samples of equal lengih with 0.000002 inch,

flat within 0.000004 inch, and within 0.000008 inch of the desired

size has proved the practicability of the method. Upon receipt of

this I'eport the Ordnance Department made an allotment to cover manufacturing cost and commissioned the inventor. Bureau machinery and other machinery and special apparatus purchased under

the allotment was installed and manufacture begun. By the close of the year more than 3,500 gauges had been manufactured, accurate within 0.000005 inch, and assembled in sets the total value of which,

compared to the price of the fonnerly imported gauges, exceeded

the amount of the allotment. The cost of experimental work and

all machinery purchased was in this manner virtually saved by the

Government in the first year's production.

Gauge Storage and Distribution.

Following inspection and acceptance by this Bureau of master

gauges purchased by and for the use of the Ordnance Department,
38 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

gauges were classified and stored to await shipping instructions to points where munitions were approaching completion and master

gauges would be required in connection with their acceptance. Between two and three thousand gauges were stored and shipped

monthly in this manner. After the general cancellation of munitions contracts all the remaining gauges at the Bureau, except three

or four thousand, representing one of each type and size, were

shipped to arsenals designated hj the Ordnance Department. These

remaining gauges are in possession of the Bureau, subject to call for reference purposes.

Gauge Salvage and Manufacture.

During the year 487 new master and inspection gauges were manufactured, and 962 additional obsolete gauges wei'e salvaged for the

Ordnance Department to conform to revisions in the designs of

munitions components for which the gauges were originally procured. This was done as exigency work in the gauge shop only when

serious delay would result from the regular method of procuring

gauges from outsidcmanufacturers through obtaining bids and placing contracts, or when a small amount of work would salvage obsolete gauges and save the much larger expense of contracting for

entirely new gauges.

Five additional lead testers were manufactured for the Ordnance

Department during the past year, so that one machine has now been

supplied for each of the principal arsenals. Instruction Courses.

Three two-week courses of instruction covering the measurement

and use of our special gauge-testing apparatus and study of methods

particularly adapted to field work were given at the Bureau. The

courses were attended by a total of 60 supervisors and gauge inspectors, among whom were represented 13 district ordnance offices, 2

navy yards, 2 arsenals, the Motor Transport Service, and 4 large

manufacturers having war contracts. Design and Construction of Apparatus.

The following new designs of gauge-testing apparatus have been

made to embody the results of experimental work: Simplified projection lantern of short range with horizontal projection, groundglass screen, and equipped with incandescent arc illumination; an improved and simplified balanced micrometer to be used for pitchdiameter measurements of thread gauges by the three-wire method;

a mechanical indicator to replace the optical lever system on the

Bureau's lead-testing machines; apparatus for the measurement of

periodic lead errors in plug-thread gauges ; a device for standardization of wire measurements.

Apparatus and instruments are under construction at the present

time for all of the above designs. In addition to this work, the shop

has built during the past year practically all of the special apparatus

required for the Washington laboratory and branches.

Research.

Research work has been carried out largely in connection with

problems of the National Screw Thread Commission. Experiments

have been made to determine suitable tolerances, allowances, and
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 39

interference values for various classes of fit. Study has been made

of methods of manufacturing taps and screw-thread gauges, together

with the effect of errors in taps on the size and character of tapped

holes. Proposed tolerance systems have been worked out, tabulated,

and charted. Questionnaires have been prepared and issued, through

which information has been secured from manufacturers and users of screw-thread products relating to current practices. Replies have

been studied, classified, and tabulated.

Reports on Communications.

The following mimeographed communications which have been

prepared or revised during the 3-ear are available for distribution:

B461. Symbols for screw-thread notation and formulas. B466. Procedure of tests and explanation of reports of munition limit gauges by Bureau of Standards. B467. Gauge tolerances used by Ordnance Department, United States Army.

B506. Important screw-tbread systems. B507. Sliop inspection of taper-thread gauges. B510. Construction and operation of projecting apparatus for measuring

screw-thread gauges and profiles. B512. Interchaugeability of United States standard and British standard

Whitworth threads by diameter modiflcation. B513. Services available at the Bureau of Standards gauge laboratories. B514. Drawings and explanation of drawings used in manufacture of

pitch-testing device. B516. Important European screw-thread systems. B517. Thread form and clearance of thread gauges. Bol9. The measurement of radii on profiles. Bo20. Testing of flatness of gauging surfaces. A number of articles regarding the Avork of the gauge section have

appeared in various mechanical trade journals and scientific magazines. Program.

A large amount of valuable data have been collected relating to all phases of war-time gauge work of the Bui'eau. From experience it has been possible to advise manufacturers on a great many subjects

relating to the proper design, inspection, and use of limit gauges.

This work is being continued and will be supplemented by literature

prepared and distributed in such a manner as to reach and benefit

the largest number of manufacturers and interested parties possible.

Standardization, research, routine testing of commercial gauges and

standards, and development of measuring apparatus will form important parts of the future work of the gauge section.

TIME-MEASURING DEVICES.

(Origin and improvement of methods of test, and the testing of watches, clocks, and

chronometers, and preparation of specifications therefor.)

Practically the whole efforts of the time section have been devoted

to the testing of timepieces for the United States Shipj)ing Board.

This work, unlike other work, began during the Avar, and was not

discontinued at the signing of the armistice, as the original shipbuilding plans of the Government were not thereby greatly modified.

This section has completed the following tests during the year

:
40 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Kind.

Class A watches SMp watches Comparing watches

Stop watches

Wrist watches Deck clocks

Number

tested.

82

1,395 1,360

1,996 200

4, 778

Length

of test in days.

54

31

16 a 1212

21

Fees.

$311 6,975

1,360

594SO

4,778

Kind.

Airplane clocks Chronometers

Investigation Master clock system

Total

Num- Length

ber of test Fees.

tested. in days.

OO $132

9 31 95

2 31 10

1 100 5

9,856 14,310

a Minutes. Of the 82 watches submitted to the class A test, certificates were

granted to 19, of which 17 were of American manufacture and 2 European; certificates were refused to 63 watches, of which 25 were

of American manufacture and 38 European.

GAS MEASUREMENT.

(Design and improvement of apparatus, and the investigation and improvement of methods of tests of gas meters and meter-proving apparatus and other instruments used

in connection with the flow of gases; testing of meters and meter-proving apparatus.)

Testing of Town-Border Natural-Gas Meters for United States Fuel

Administration.

In connection with its program of conservation of the naturalgas resources of the United States, the United States Fuel Administration requested the Bureau to test the natural-gas meters established at the town borders of a large number of cities and towns of

Kansas and Missouri. Accordingly, the Bureau sent into these States

members of its staff, who during the months of November and

December, 1918, and January, 1919, tested a total of 103 large meters. Of these 1-2 were proportional meters, 2 pitot-tube meters, 33 orifice meters, and 66 positive-displacement meters. On the basis of the Bureau's findings and the price of artificial gas, it has been estimated that during 1918 several million dollars' worth of gas was lost by leakage in the distributing plants recei-\dng

gas through the the meters tested. Meters Tested in the Laboratory.

A considerable number of meters of miscellaneous types were

tested in the laboratory. These meters were all for use in testing

and research work by the War Department and various scientific institutions.

Investigation of Claims of Tide Motor for Post Office Department.

Upon request of the Post Office Department, the Bureau examined

the claims made for a tide motor which was being advertised through

the mails. The exhaustive examination made of these claims showed

them to be false, and, as a result, the use of the mails in advertising

the device was prohibited by the Post Office Department.

Consultation.

The Bureau has been consulted frequently by Government departments and others regarding the solution of gas-measuring problems

and has usually been able to give material aid.
EEPOKT OP DIBEOTOR OF BUREAU OF STANDARDS. 41

Publications.

Household Weights and Measures, Miscellaneous Publication No.

39. This consists of a card designed to be hung in the kitchen, whicli

contains a large amount of weights and measures information fre- quently of use in the household.

Orifice-Meter Investigation.

Preliminary work has been commenced on the determination of

the coefficients of orifice meters for gas measurement. It is planned

to make a thorough investigation of this type of meter in order to correlate and verify the work previously ^ done by various investigators. These coefficients involve accuracy of the measurement of

large quantities of natural gas, air, and steam. Photographic Method of Detecting Camouflage and Changes in a Complicated Group of Objects.

The Bureau devised and developed, in cooperation with the United

States Signal Corps and United States Air Service, a photographic

method of detecting camouflage. The method consists of making

two photographic negatives of the group of objects, one before the

change and the other afterwards. A positive is made from one of

the negatives, and this is superposed upon the other negative. If no

change had occurred between exposures, the combination would form

a field of practically uniform photographic density ; but changes are plainly indicated by discontinuities of density. It is believed that

the method ha,s considerable commercial value for engineering work,

detective work, etc. THERMAL EXPANSION.

(Determination of thermal expansion of various materials.) The expansion of a number of special alloys and materials over

consideralale range of temperature were studied during the year. The curves of a number of these materials were determined for the

first time, and consequently they constitute valuable contributions to the available scientific and technical data. Altogether 121 specimens were studied, the materials being as noted below

:

Material. Number

tested.

Schedule fee. Material. Number

tested.

Schedule fee.

4932

23

4

4

32

$735

1,876

784

13782

68

100

limestone 1

11

1

$25

3338

55

Steel Hard rubber

Stellite

Celluloid Total 121 3,933

Over one-half the above tests are in response to military requests.

Researches.

Porcelain.—Most of the porcelains were tested in connection with

the Bureau's spark-plug research conducted at Pittsburgh and Washington. Expansion data are very essential in this work, since it is
42 KEPORT OF DIRECTOR OF BUREAU OF STAlfTDAEDS.

necessary to have the expansion of porcelain matched by that of the

metallic electrodes if cracking is to be prevented.

The 49 copper alloys are a part of the original 129 submitted in

July, 1916, by the American Brass Co. as a cooperative research.

There still remain 10 specimens in this lot. Dental Amalgams.—An extended series of experiments on dental

amalgams were conducted at the request of the Surgeon General of

the Army. There are no definite specifications for these materials.

Personal opinion and crude tests have been relied upon in the past

in grading them. Because of the complexity and minuteness of the

dimensional changes taking place during the amalgamation of alloys

interference methods have to be employed to study them.

The net result of all tests has shown that many alloys sold as "balanced" or "according to certain principles" in no sense develop the

qualities which are supposed to accompany such products.

Comparative results on 12 alloys submitted to the Surgeon General

of the Army for purchase were recently completed. This will be

used as a basis for making decisions until permanent specifications are written.

Permanent specifications are to be prepared by this Bureau, with

the cooperation of the Research Institute of the National Dental

Association.

Dividing Engine.—Finding it impossible to repair or improve the

present equipment of dividing engines in use or to purchase satisfactory ones, the Bureau has begun the design of new machines for

future use. A study has been made of the design and accuracy of

existing machines, and from this it is hoped the Bureau will be able

to improve its equipment of apparatus.

New Expansion Furnace.

The new high-temperature (1,000° C.) furnace for thermal-expansion measurements has been installed and is giving excellent satis- faction. Numerous tests of steel and iron have been carried beyond

the recalescence temperature and detailed information secured in this

region.

By attaching the position wires in V notches cut in the side of speci- mens it has been found possible to eliminate the errors due to blistersl which appear on specimens heated above 700° C. Publications.

Bulletin 15 Avill include a paper on "Thermal Expansion of Molybdenum" issued by this section.

A second paper, "Thermal Expansion of Porcelain, Phenol Products, Marble, etc.," is now in the hands of the editorial committee.

COMMERCIAL SCALES.

(The testing of railroad tracli scales, elevator scales, mine scales, other commercial

scales and weighing and measuring apparatus ; specifications for and capacity rating of

scales.

Mine-Scale Investigation.

The investigation of mine scales has been continued, and the work

has been carried into several new fields, notably in Ohio, West Virginia, and Kentucky. There is a great demand for work of this

character, and it is being pushed as rapidly as possible with the fa-
BEPOKT OF DIRECTOR OF BUREAU OF STANDARDS. 43

-cilities at hand. Very bad conditions have been encountered and rectified in the various regions, and many complaints have been investigated and amicably, adjusted. As a result, a better understanding

between the miners and operators has been created and greater effi- ciency in this industry is thus being brought about.

In Maryland sei'ious inaccuracies of scales were found in a number of cases, and faulty and unlawful methods of weighing and in- correct tare weights were found in use. In order to rectify these conditions, a number of cases were brought to the attention of the Grand

Jury by the State's Attorney, and at his request representatives of the

Bureau appeared before the Grand Jury and testified as to conditions

found. A number of indictments were obtained, and the cases were

tried in the State courts. Several convictions were obtained, while

in other cases the defendants were found " Not guilty " on account

of lack of knowledge as to the inaccuracy of their weighing equipment. The cases had the result of effectively demonstrating the

necessity of regular tests, quieting the suspicions and discontent of

the miners and clarif^'ing the meaning of the State mining law.

Railroad Track-Scale Investigation.

The testing or railroad-track scales has been continued throughout

the year, although it has been found impossible to keep the equipments in the field at all times on account of lack of sufficient funds

for this work. The Bureau has continued to cooperate with the

United States Eailroad Administration under the terms of Circular

No. 13 of that administration, and reports of all tests of track scales belonging to the railroad companies have been furnished to the re- gional directors and the Federal managers of the roads concerned.

Many of these officials have been making a determined effort to improve conditions on their lines, and in these cases the recommendations of the Bureau have been promptly complied with. As a result,

in some sections conditions have doubtless been very materially improved. Ten master scales on the various lines have also been in- spected and tested in order to maintain the standard of weight of the

test cars operated by the railroad companies.

While special attention has been paid to scales belonging to the

railroad companies as mentioned above, nevertheless a number of

industry track scales, especially where tests were requested by rail- road companies and State departments, have also been tested in con- nection with this work. Track scales have also been tested for the

Government, States, and cities. A summary of tests made follows

:

Scales tested. Number

tested.

Correct. Incorrect.

Number. Per

cent. Number. Per

cent.

352 153 43 199 57 Industry track scales 312 156 50 156 50

17 4 24 13 76
44 KEPOET or DIKECTOB OP BUREAU OP STANDAEDS.

The tolerance allowed on the track-scale tests is the same as m

former years, namely, a maximum allowable error of 200 pounds in

weighing a car of 100,000 pounds, gross weight.

Some idea of the extent of the distribution of the above work may

be gained from the fact that scales upon the lines of 78 different

railroads were included, tests being made in the District of Columbia

and the following 32 States : Alabama, Arkansas, Colorado, Georgia,

Idaho, Illinois, Indiana, Iowa, Kansas, Louisiana, Maine, Massachusetts, Micliigan, Mississippi, Minnesota, Missouri, Montana, New

Hampshire, New Mexico, New York, North Carolina, North Dakota,

Ohio, Pennsylvania, South Dakota, Temiessee, Texas, Utah, Vermont, Virginia, Wisconsin, and Wyoming.

In addition to tests made above, some special investigations of lo- comotive scales have been undertaken at the request of the U. S. Railroad Administration at seven plants with which the latter has contracts for furnishing new locomotives. These locomotive scales are

scales of special design for the purpose of determining load distri- bution on locomotive drivers. The work has been completed in 3

of these plants, 29 scales of this type having been tested. Many of

these were found to be of faulty design and very seriously inaccurate.

Inspection and Test of Other Weighing and Measuring Apparatus.

Inspections and tests of a number of weighing and measuring devices have been conducted in order to ascertain whether their construction and accuracy were suitable for the purpose for which they were intended. This work was done at the request of various

Government departments, manufacturers. State officials, and others,

and included the investigation of several new types of liquid-measuring pumps. Tests were also made of a number of large-capacity

scales at the Washington and Philadelphia Navy Yards. Also early

in the year, representatives of the Bureau made very extensive tests of the weighing equipment at the Government powder-manufacturing

plant, at Nitro, W. Va., in order to enable that plant to get into production. In compliance with an urgent request of the War Department, a special investigation was made of the weighing equipments

at the Government powder-bag-loading plants located at Woodbury,

N. J., and Tullytown, Pa. These plants were just beginning to operate at that time, and, since they were constructed primarily to supply ]DOwder charges to the American Expeditionary Forces in France,

it was important that they be equipped with the best weighing apparatus and use the best weighing methods, so that maximum production could be obtained. A detailed report was made of the conditions

found, and recommendations were included which were immediately

put into effect by the War Department officials. Standardization of Large Test Weights.

The large test weights—namely, 10,000 pound and 2,500 pound

weights—which make up the 100,000-pound loads on each of the

test cars Nos. 1 and 2, were brought to the Bureau of Standards

for recalibration. Since these weights are carried inside of

freight car, they are not subject to change in weight clue to excessive wear, loss of parts, etc., as is the case with the railroad type of scale

test car and therefore do not require checking so frequently. However, there is a slight change in their Aveight clue to wear of paint.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 45

oxidation of iron, etc., which makes recaliberation from time to time

necessary. All of the weights were repainted and adjusted. After this adjustment the probable error of each set of 100,000 pounds is 0.1 pound,

or inaccuracy of 1 part in 1,000,000.

Specifications for the Manufacture and Installation of Railroad

Track Scales for Ordinary Freight-Car Weighing.

The entry of the United States into the war delayed the issuance

by the Bureau of Standards of final specifications for railroad track

scales, which had been previously issued in preliminary form for

comments. The subject of railroad track scales was, however, a matter of too great economic and industrial importance to abandon

entirely. After the war work had become organized and under

way, it became possible to give increasing attention to "track scale matters. The Bureau has always made it a point to cooperate with

all who have a legitimate interest in this subject, including the

officials of States, railroads, manufacturers, and private concerns. The regional director of the United States Eailroad Administration for the Northwest region called together a meeting in Chicago

to discuss the specifications which the State of Minnesota had

adopted and were planning to put into effect on December 1, 1918.

On account of war conditions it was desired to postpone the date

at which these would be effective, since to meet the specifications

would hamper the railroads under war conditions. The representatives of the State of Minnesota agreed to this, and the purpose of the

meeting was accomplished. Furthermore, there was an apparent

spirit of cooperation present which was promising. As a result the

regional director for the northwest suggested that a committee be

formed for the purpose of harmonizing the specifications for rail- road track scales prepared by different agencies. This suggestion was acted upon. The Bureau of Standards indorsed this as a practical means for progress and was represented on this committee.

This work lasted a large portion of the year. On this committee were represented the American Railway Association, the American Railway Engineering Association, the Eailroad and Warehouse Commission of the State of Minnesota, the

National Scale Men's Association, the Scale Manufacturers' Association, and the Bureau of Standards. This committee drew up specifications which met the approval of all of the members and embodied

features which the Bureau of Standards, as a result of its experi- ence in railroad track scale work, advocated as desirable and necessary. It is believed that these specifications will be widely adopted and

result in a standardization of railroad track scales throughout the

United States to the extent that standardization is valuable, and will

result in a marked improvement in railroad weighing.

Specifications for Scales for Weighing Grain.

The subject of defining what constitutes proper and adequate

facilities for weighing grain has recently assumed large importance,

and hearings relating to this matter were held by the Interstate Commerce Commission under docket 9009, dealing with loss and damage

claims for grain in bulk shipments. The Bureau of Standards co-
46 REPORT OP DIRECTOR OF BUREAU OF STANDARDS.

operated in trying to solve the difficulties by having a representative on a committee organized for the purpose of drawing up specifications defining what constituted proper facilities for weighing grain.

It was neither practical nor possible under the circumstances to make

an exhaustive investigation of the matter similar to that which had

been carried out by the Bureau for railroad track scales, but tenta- tive specifications were drawn up which represented the best information available on the subject.

These specifications were submitted to the Interstate Commerce

Commission, which in turn submitted them to a joint committee

representing the shippers and carriers, formed for the purpose of

agreeing upon just and practical rules to govern the settlement of

loss and damage claims.

If these specifications are accepted by the shippers' and carriers'^ committee, the Bureau of Standards will probably give them its indorsement and issue them as a circular.

Eailroad track scales for weighing grain have been studied by the

Bureau in connection with its railroad track-scale testing equipment. Hopper scales and automatic scales are matters on which

much work remains to be done before any decision can be reached as

to just what equipment and installation is required to secure accurate

results, and the best and most economical manner of designing,

installing, and using such scales. WEIGHTS AND MEASURES LAWS AND ADMINISTRATION.

(Cooperation vrith States in the administration of weights and measures laws ; promulgation of specifications and tolerances for apparatus, and of rules and regulations ; en- forcement of standard barrel laws ; conducting weights and measures investigations ; an- nual conferences of State and local officials on weights and measures.)

Cooperation with States and Other Interests in Weights and Measures Administration.

On account of the very material increases in the cost of all necessities of life the need of efficient inspection of weights and measures

in commercial use is being more and more strongly felt, and several States have recently enacted laws establishing State-wide inspection

for the first time. Among these may be especially mentioned Texas^

North Dakota, and South Dakota, all of which have established comprehensive laws. Other States have added to their general code on

this subject, while still others are conducting investigations to find

out what character of legislation is needed. In connection with this

activity, the Bureau of Standards is receiving an increased number

of requests for assistance in establishing State departments, in

conducting field investigations in various localities, in passing upon

types of weighing and measuring apparatus to determine its fitness for commercial use, etc. Enormous good would doubtless result from

increased activity in these fields of work, but lack of appropriations

make it impossible to accede to many requests, even of the greatest

urgency.

As a specific instance of the character of assistance requested may

be mentioned legislation recently passed in the States of Maine and

Texas. In the former State this becomes of force and effect on

July 1, 1920, and provides that after that date no weighing and

measuring apparatus may be sold in the State which has not been
REPORT OP DIRECTOR OF BUREAU OF STANDARDS. 47

approved by the Bureau of Standards. In the latter State any

apparatus approved by the Bureau of Standards may be sold without

a special certificate from the State authorities. Unless an appropriation can be obtained for this work it will be impossible for the

Bureau to undertake it, since it would be futile to attempt such a task with the present staff and facilities available. As a result, laws

designed to protect the merchants and consumers of this State will

be nullified. Yet not only would the results of such an investigation

be of assistance in the States mentioned, but to all other States as well, many of which would rely upon the Bureau for technical infor- of this kind. Desirable uniformity could thus be brought about.

Other States, among which may be especially mentioned Virginia,

desire information as to conditions existing in order that a basis for

weights and measures legislation may be obtained. In these cases

also the Bureau is often unable to proceed on account of shortage of

funds. The need of a special appropriation for carrying on the work

of cooperation with the States in weights and measures matters is very urgent.

Representatives of the Bureau attended State conferences of

weights and measures officials in Michigan and New York and gave

addresses on subjects of interest to the delegates.

Proposed Federal Legislation.

Congress has not enacted any legislation on the subject of weights

and measures during the past year. However, the Bureau has been

working on a draft of a bill designed to standardize flour, meals, and

commercial feeding stuffs throughout the United States, upon the

hundredweight basis. This proposition was first brought before

Congress last year, and since that time work has been done in per- fecting it so that in its present form it has the hearty indorsement

of all interests concerned, including the Millers' National Federation, an association comprising the large majority of the flour producers of the country, the American Corn Millers' Federation like- wise including a large majority of firms in this industry, and every

State association of weights and measures officials where the bill was

considered, including New York, Massachusetts, Indiana, Wisconsin,

Michigan, and Maine. Briefly, the bill eliminates the 196-pound barrel and the cumbersome and nonuniform subdivisions thereof now

standardized in the various States and substitutes in their place the

200-pound barrel, with subdivisions of 100, 50, 25, 10, 5, 4, 2, and 1 pound. If this bill is enacted into law, a long forward step in uniform standardization of packages will be obtained, and some of the

most important foodstuffs sold in package form will be efficiently

and adequately regulated.

Twelfth Annual Conference on Weights and Measures.

In order to assist the various State and local departments enforcing weights and measures laws throughout the United States in obtaining the greatest uniformity and in maintaining the greatest effi- ciency in their work, it has been the practice of the Bureau in the

past to invite all those officials and others interested to attend a general conference on weights and measures at the Bureau of Standards

once in each year. On account of the war these meetings were dis- continued in 1917 and 1918, but this year it was deemed advisable to
48 KEPORT OF DIEECTOE OF BUREAU OF STA^DAKDS.

resume them, and consequently the twelfth conference was held on May 21-24, 1919. Great interest was manifested in this meeting. It was more generally attended than ever before, and was in every way

a success. About 180 official delegates and visitors attended, 29 States being represented. Perhaps the most important constructive action

taken was the tentative adoption of a set of specifications and toler- ances for liquid-measuring pumps used in the sale of gasoline. These

specifications and tolerances had l:>een prepared by the Bureau of

Standards as a result of a comprehensive investigation made shortly

before the war. In general, these pumps have not been adequately

regulated in the past, and, as a result, short measure in the sale of

gasoline has been very common. With a imiform system of specifications and tolerances in use it is believed that much more success will be obtained in coping with the situation. Enormous losses to the consumer can be thus prevented and competition put upon a fair

and honest basis. Eesolutions were passed by the conference indorsing legislation

empowering the Bureau of Standards to pass upon and approve

tyjDes of commercial weights and measures and weighing and measuring devices manufactured or offered for sale in the United States; and approving the decimal weight fiour bill now pending in Congress. The conference also went on record as favoring the sale of

dry conunodities by weight ; the marking of net weight on wrapped

hams, bacon, and other meats : the standardization of packages : and

the metric system of weights and measures. About 15 years ago the Bureau of Standards announced its intention of exercising its functions in such a way as to be of maximum

assistance in regulating and improving the general condition of

weights and measures in commercial use and the mamier of sale of

commodities, and as a first step in this direction there was inaugurated the annual conference on weights and measiires of the United

States. At this meeting the representatives of the States were in- formed that to accomplish the above end the Bureau would give all necessary assistance in building up State and local inspection depart- ments. In the case of matters of such a nature that they should be

administered by the Government, the Bureau would procure and en- force necessary Federal legislation. Finally, the Bureau would act

as a general clearing house for weights and measures information

and assist in coordinating the activities of the Government and of

the various States, so that maximum efficiency of procedure would be

obtained.

For some years thereafter the Bureau of Standards was the only

Federal agency in this field and completely dominated it. Much valuable progress was made toward obtaining the objects sought. Field

investigations were made in every State in the Union, and commercial

conditions were thereby determined, a model law was drawn up and

its introduction procured in numerous States, Bureau representatives

appeared before State legislative committees in support of the legislation proposed, and it was enacted in a large number of States. Following this action Bureau representatives visited these States,

helped to establish the departments, drew up tolerances and specifications for coromercial apparatus for their guidance which were promptly adopted by a number of States, and did other necessary

work along the original lines of cooperation proposed.
BEPORT OF DIRECTOR OF BUREAU OF STANDARDS. 49

During this time, also, the Bureau undertook to procure needed

national legislation. The Federal apple-barrel law, the standardbarrel law, and the standard lime-barrel law were enacted by Congress, statutes important in themselves and more important still as a percursor of other legislation to follow. The proposed law for the

Federal standardization of type of commercial weighing and measuring apparatus was drawn up and introduced with the hearty approval

of the States. Notwithstanding these activities and achievements, the Bureau is slowly but steadily losing ground in this field, owing to the insufficient funds with which to carry it on. In the meantime, the Bureau of Markets and the Bureau of Chemistry in the Department of Agriculture, with a corps of agents in the

field and ample funds, have taken up this work and are now claiming it as their own field. The elforts of the Bureau have merely been

successful in indicating to these bureaus the possibilities in the

weights and measures field. They have procured legislation such as the Federal standard container act and are vigorously enforcing it, whereas the standard-barrel laws are entirely unenforced by the

Bureau of Standards, due to the lack of funds to put any inspectors

in the field to look after it. It is much the same in the case of State

cooperation ; the Bureau has no representatives in the field, while the

Department of Agriculture has numerous traveling inspectors who

visit the States and assist the officials on all occasions, even in weights

and measures matters. Very recently the Bureau of Markets, under

the terms of the Federal warehousing act, issued rules and regulations

requiring that scales used shall be of types approved by the Bureau

of Markets, a matter which distinctly belongs in the field of the

Bureau of Standards.

The time has now come when the Bureau should prepare to go

forward vigorously or else to turn over to others the whole practical

question of inspection, and with" it the related one of commercial

standards. If Congress is unwilling to give the Bureau a fund to take care of the laws which it now has to enforce and to enlarge its functions so that the matter can be handled in an adequate and businesslike way, it will be better for the Bureau to withdraw from the

field altogether.

The same is true, but to a lesser extent, in the track-scale work of

the Bureau. In this it has reached a point where instead of going

forward we are losing ground. Its appropriations for this work have

not been increased since 1913, when the work was commenced. In addition, it is faced with constantly rising salaries and increased ex- penses of operation of all kinds, while the demands for tests from the

States, Federal agencies, the railroads, and 'others, are steadily in- creasing. It was found necessary last year to lay up two of the

equipments for months and allow several of the best-trained field men

to leave the service on account of the lack of funds. The situation will

probably be still worse during the present year. The preliminary

work has been done, but conditions have been shown to be extremely

bad and in urgent need of competent regulation. New organizations,

such as the Eastern Weighing and Inspection Bureau, are being

formed to do work which should be done officially. The time has now

142289—19 4
50 KEPOKT OF DIRECTOR OF BUREAU OF STANDARDS.

come in this field also when the Bureau must of necessity go forward

and occupy this field of regulation or retire in favor of some organization which will be prepared to do this. One step needed to strengthen the Bureau's position in this field

is the establishment of a depot in Chicago or some other western

railroad center. Its present activities are merely successful in showing the necessity of governmental supervision of the scales used in

interstate commerce, and there are numerous indications that other

agencies are planning to take upon themselves this work. In order

to properly handle the situation, the Bureau should have at least a dozen stations strategically located throughout the country. Each

of these stations should have a master scale and the necessary test cars and equipment to supervise the test of all track and grain scales in their respective districts. Eventually an appropriation of $500,000

or more may be required. This program can not, of course, be car- ried out in one or two years, but sooner or later the demands of farmers' organizations and others using railroad track-scale weights

will be heeded by Congress, and that agency which occupies the

largest part of the field and shows itself most competent to handle

the matter will be designated by Congress to do so. The position of the Bureau in this field is as strong as it is likelj'^ to be with its present facilities. As more State organizations are formed and the railroads consolidated the Bureau's position will be- come relatively weaker. It is therefore strongly recommended that

every effort be made to secure the appropriation for the depot asked

for last year and again this year without success. Routine Testing.

The routine testing in section 1, length; section 2, mass; and sec- tion 4, volumetric, of this division is from three to six months behind. This condition is due to the fact that for some reason, probably the recognition of the commercial iraiDortance of technical and

scientific work brought about through the war, an increase has re- sulted in the use of certified apparatus of the kind handled by the

sections mentioned above. Every effort has been made by those en- gaged in this work to promptly dispose of it, but it has been beyond

their capacity. As the work is now conducted it only creates dis- satisfaction and brings severe criticism upon the Bureau and its employees, which is unwarranted, as important research work has

been abandoned to care for routine tests. Not only are needed re- searches and investigations halted, but the testing is not done with

that care which should characterize all of the work of the Bureau.

The Bureau has issued circulars giving the fees, and has been doing

this work for a number of years. It has educated the public as to the importance of using apparatus that has been certified by a competent authoritative agency, and it should continue to do this work so

essential to American industries, if it can be done with crecUt to the

Bureau, or at least without discredit.

If Congress does not deem it proper to provide for this work for

which estimates will be submitted, it would be well to consider the

proposition of placing it on a self-supporting basis. It is hoped,

however, that this need not be done, since such a plan has many

disadvantages and often leads to embarrassing circumstances.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 51

2. ELECTRICITY.

[Electromotive force, resistance, current, inductance, capacity, conductivity, insulation, magnetic permeability and hysteresis, radioactivity and radiocommunication, including researches on electrical units and standards, measuring instruments, and methods of measurement, and cooperation with standardizing committees of technical societies, with

testing laboratories, the electrical industries, public-service companies, and public-utility commissions, municipalities, and engineers upon problems of standardization, including standards of adequacy, and safety of service.] Scope of the Electrical Work.

One of the most important functions of the Bureau with respect to

electricity and allied subjects is the establishment and maintenance

of the fundamental standards upon which all electrical measurements

are based, including cooperation with similar institutions in other

countries so as to secure international uniformity. This includes the

intercomparison of standards and extensive research in methods of

measurement and the development and improvement of subsidiary

and derived standards. These standards are utilized, and the results of the researches are immediately applied in the testing of reference

standards and instruments for manufacturers, testing laboratories,

universities, research institutions, electric utilities, utility commissions, engineering and other interests, and various agencies of the

Government.

The testing of electrical instruments and apparatus is of two main

classes : First, there is the standardization of reference standards and

precision instruments for manufacturing and other institutions which

themselves make or standardize instruments for commercial use or which conduct research work. It is through the work of such insti- tutions that the measurements made in practice are referred back to the standards of the Bureau. Second, a limited amount of testing

of commercial electrical measuring instruments, radio and photometric apparatus, magnetic materials, etc., is done, chiefly for the

purpose of keeping the Bureau in touch with the needs of the

industries, of developing methods, and of improving apparatus and

materials. The greater portion of this testing is done for the Government services, and serves the double purpose of providing information to be used in formulating specifications and of determining

the quality of materials furnished upon them.

The research work has mainly to do with methods of measurement,

the determination of the electric and magnetic properties of materials, and the development of those phases of engineering science in

which measurement plays an important role. Electrical, radio, and

illuminating engineering interests are all served by these investigations. The Bureau also renders important service, both directly and

indirectly, to manufacturing and other industries. Much of this in- vestigational work is on the more fundamental aspects of the principles involved, so that the results may be applicable to a class of

problems rather than being limited to the one specific problem under

investigation. The work on correlation of magnetic and mechanical

properties of iron and steel and in the stlidj^ of galvanometers are examples.

The research work in radiocommunication, magnetism, radioactivity, and photometry is along lines quite similar to that in the more purely electrical measurements. Standards have been and are being developed, methods of measurement are being improved, and
52 REPORT OF DIRECTOR OE BUREAU OF STANDARDS.

important special problems of significance to the industries, and in a number of cases of particular importance to the Government, are being investigated. Specific examples of the projects in hand during

the past year are given in the sections below.

Special Military Work in Electrical Subjects.

During the first half of the year the demands for service to military departments were so numerous both in testing and in research

that the resources of the electrical division, like those of other parts

of the Bureau, were very largely devoted to such service. This in- volved an increased amount of work similar to that performed in

ordinary times, including consultation with other departments on a larger number of technical problems. Extensive experimental investigations of a few important military problems begun during the

preceding year were also actively continued.

Since the cessation of hostilities attention has naturally been

turned to the revival of the normal work of the Bureau, but a large

amount of time has been required to bring the military work to a

satisfactory conclusion and to iDut the results in such form that the

labor already expended should not be lost. Furthermore, many of

the investigations begun on account of military needs are equally

important in times of peace, and even equipment specifically developed for military use has in some cases been found applicable to industrial needs. These considerations have made it appear inadvisable to cut off immediately the activities which arose from the war, and it is hoped that means will be found to continue permanently some of the more important of these activities without sacrificing the

fundamental work in electrical research previously carried on. Standardization of Electrical Equipment and Supplies for the War

Department.

In order to simplify the handling of purchases of equipment and

supplies for the War Department, the Standardization Section of the

Purchase, Storage, and Traffic Division, General Staff, in August, 1918,

appointed a committee on standardization, consisting of one member

from each bureau of the War Department and one from the Bureau

of Standards. This general representative of the Bureau was designated from the electrical division; and while some subcommittees of

the general committee on standardization dealt with supplies of other

kinds and called on many sections of the Bureau for information

and assistance, the most active work was done in cooperation with

the various subcommittees on electrical supplies. To this work three

members of the Bureau staff gave practically all their time for several

months, while a number of others contributed materially to the work

of committees in their special fields. Through the activities of the Bureau representatives the standardization committee was brought into touch with war-service committees of the various branches of the electrical industry, and a plan

of discussion of proposed schedules and specifications was adopted

which gave all interests concerned an opportunity to present their

views to the committee. A close-working connection with the subcommittees of the standards committee of the American Institute of

Electrical Engineers was also established through the Bureau's repre- sentation on that committee, and their assistance was obtained in the
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 63

preparation of a considerable number of specifications for apparatus

and material.

A considerable amount of testing was also required in connection

with this work. Some of this was of routine nature as regularly car- ried on by the various sections of the electrical division, but other

tests constituted rather extensive investigations, such as those on

trucks and tractors and the storage batteries used in such vehicles

and on protective lighting equipment. These are described later under the appropriate sections.

The results of all this standardization work were incorporated in a

catalogue of supplies for War Department purchases which has been

issued by that department. In several fields the work done emphasized the need of further extensive investigations, and the Bureau has been specifically requested to undertake investigations on

miniature electric lamps, transformers, electric fans, storage batteries, stranding of cables, and insulation problems in connection

with rubber-covered wires and cables, which would involve a large

increase in its work in all these fields. Some of these investigations

it is planned to undertake, but the adequate handling of most of

them must await an increase in the resources available for the work.

STANDARDS OF RESISTANCE.

(Maintenance of fundamental standards of electrical resistance, calibration, and devel- opment of practical resistance standards and apparatus, testing of conductors and of con- ductivity of materials, galvonometer design.) With the exception of necessary work in routine testing of apparatus and materials, this section has given all its time during the

past year to special problems arising from the war, the more important of which are described below.

Nondestructive Tests of Welds.

Some method by which the quality of welds, especially welds in

ship plates, may be determined without the destruction of the weld

has been very much needed. It has been suggested that if the elec- trical resistance of such welds could be measured it would give an

indication of the quality of the weld without destroying it. Such

measurements, however, were considered impracticable, if not impossible. An investigation was made which showed that with a current and

potential terminal on either side of the weld and all four terminals

fairly close together the resistance of a small portion of the plate,

including a part of the weld, could be determined rather easily with

the accuracy required. For example, a saw cut extending a quarter

of the way through a half-inch plate could be easily detected by this means from either side of the plate. However, it appears that plates

poorly welded may make excellent electrical connection with each

other, and consequently the resistance method is not successful as a means of determining the quality of such welds.

Control of Airplane Guns.

At the request of the Division of Military Aeronautics and the Inventions Section of the General Staff, this section of the Bureau un-
54 KEPORT OF DIRECTOR OF BUREAU OF STANDARDS.

dertook an investigation of the possibility of using electrical means

for the control of airplane guns which must shoot between the blades

of the propellers. The time between successive passages of the propeller blades through the same position is about 0.02 second. It is, therefore, necessary that the shots be timed with respect to the time

of passage of the blades through the line of fire to better than 0.02 second. That is, the control apparatus must perform its function,

the firing mechanism of the gun must operate, the primer explode,

the charge explode, and the projectile pass through the barrel and

past the propeller in less than 0.02 second if the apparatus is to operate at all speeds without compensation for changes in speed.

An electrical-control apparatus was developed which performs

its function in a few thousandths of a second, so that the over-all

time of action, up to the passage of the projectile 4 feet beyond the

muzzle of the gun, is about 0.01 second. This type of gun control

has many advantages over the mechanical and hydraulic types generally used, and further development incidental to its use with various types of gun is being carried out by the Division of Military

Aeronautics with the cooperation of the Bureau.

Action of Browning Field Gun.

At the request of the Ordnance Department of the Army, an in- vestigation of the action of the Browning field gun was made for the

purpose of finding out whether faulty action of the reciprocating

parts was responsible for excessive breakage of the casing which was

found to occur in service. The relative positions of the three principal reciprocating parts were determinecl throughout their cycles of

operation, both when the gun was operated by hand and when it was

firing. The results obtained showed that throughout the cycle each

of these parts remained in a proper position with respect to the

others and that consequently their action was presumably not the

cause of the breakage. The methods used in this investigation were

largely electrical and involved the services of electrical experts.

INDUCTANCE AND CAPACITY.

(Methods of measuring inductance and capacity, preservation, and calibration of stand- ards of inductance and capacity, design of apparatus involving inductance and capacity

phenomena, development of formulas for computing inductance and capacity, measure- ment of short-time intervals. 1 Inductance and Capacity Laboratory.

With the exception of necessary work in routine testing, this sec- tion has devoted practically all its time during this year to militai-y

problems. The amount of testing has increased considerably, especially during the latter half of the year. The development of formulas for the alternating-current resist- ance and inductance of a " return circuit " has been completed, and

the formulas have been applied to experimental results obtained by

others, showing good agreement. A paper giving the derivation of

the formulas and a discussion of the results has been prepared for

publication under the title, " An Integration Method of Deriving the

Alternating- Current Resistance and Inductance of Conductors."

Measurements of the resistance and inductance of a " return cir- cuit" composed of No. 2 copper wire have also been made in the
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 55

laboratory at frequencies of 500, 1,000, 2,000, and 3,000 cycles per

second, and the measured values agree very well with those calculated by the formulas.

Gun-Firing Investigations.

The gun-firing investigations which this section undertook for

the Bureau of Ordnance, Navy Department, some time ago have

been continued throughout the year, and the scope of the work has

been broadened until now it covers a large part of the field of ballistics. A study of the work that has been done by others along similar lines indicates that the section has collected a larger amount of

data concerning the behavior of certain types of guns than has been

collected heretofore. The chief investigations which are being car- ried on by the section at the present time are listed below.

Theoretical Study of the Motion of a Projectile.—Prof. H. C. Richards of the Physics Department of the University of Pennsylvania spent the summer of 1918 at the Bureau studying the theory

of the flight of a rotating projectile. He consulted all available

literature and attempted to reconcile the theories with the experimental data available. Dr. Richards has continued his interest in

this subject throughout the year and is preparing a report of his

work.

Study of Variations of Gton Pressures with Time.—Data obtained

during the experimental firing on naval vessels indicated the need

of a time-pressure gauge. K\\ experimental gauge was designed and

built at the Bureau during the summer and fall of 1918. It was

tested by placing it in a bomb in which a small charge of powder

was exploded. As these experimental tests gave very promising results, the Bureau of Ordnance ordered five gauges made for use in

certain of the naval guns. These gauges have been completed and

are now being given the final tests at the Bureau. Recently the

Ordnance Department of the Army requested the use of these gauges

in their work.

Primer-Explosion Times.—In the work during the previous year on electric cannon primers it was assumed that the breaking of the

platinum bridge wire indicated the explosion of the primer. Subsequent experiments, however, showed that this was not always the

case. An additional investigation was, therefore, carried on in

which the time of the explosion of the primer was taken as the time

at which a fuse wire placed in front of the primer was broken by

the flame. A number of makes of primers were used in the investigation. It was noted that the older primers were slower in firing

than those of recent manufacture. The Bureau of Ordnance has

requested that the investigation be continued, using a large number

of primers .of as many different " ages " as possible.

Ejection Velocities.—In the study of factors which may cause dis- persion of fire there is need for a method by which the muzzle velocity of each projectile fired from the ship can ,be measured. Considerable time during the past year has been spent in the study of this

subject, and a method has been developed by which the "ejection

velocity " of a projectile may be determined on shipboard with an

accuracy of approximately 1 per cent. The velocities so obtained
56 REPORT or DIRECTOR OE BUREAU OE STANDARDS.

are designated as " ejection velocities," since they differ slightly from

those usually defined as " muzzle velocities."

Study of Recoil.—Eecoilmeters have been built which, in connection with the oscillograph, record the time at which the gun passes

certain predetermined points in its recoil and counterrecoil. From

these data a space-time recoil curve can be plotted. By successive

graphical differentiation of the space-time recoil curve, velocitytime and acceleration-time curves maj^ be obtained. Theoretically

these curves should furnish information regarding the velocity of the

shell inside the bore of the gun and the variation of powder pres- sures witliin the gun chamber. Eesults so obtained, however, do not

agree with those obtained from the theorj' of internal ballistics and

indicate that this theory is not as well known as it should be. The

study of the recoil also gives information concerning the forces which

the gun mountings must withstand during the recoil of the gun.

Firing-Time Intervals.—A study of the firing-time intervals which

occur during the firing of the gun has been continued in cooperation

with the Navy during the year at Indian Head and aboard ship.

The chief items of interest to be noted in this work are that the powder interval—^that is, the interval which elapses after the primer ex- plodes and before the gun begins to recoil—varies largely for differ- ent shots, and that the barrel time—^that is, the time after the beginning of recoil until the ejection of the shell—^is a function of the gun

a,nd its mounting.

Jump and Whip< of Guns.—Kinemeters, which have been used in

experimental firing, have been constructed for the Navy and measure

the jump and whip of a gun at the instant it fires. Velocity Inside Bore of Gun.—During the latter part of the year

the Coast Artillery has been cooperating with the Bureau in the design of apparatus for determining the velocity of the shell as it moves

through the bore of the gun. This apparatus is now being completed in the shops of the Bureau.

Velocity Measurements iy Means of Magnetic Effect of Projectiles.—In the past a number of attempts have been made to determine the velocity of a projectile by shooting it through coils of wire

and using the current induced in the coil to determine the time at which the shell passed through the coil. In general, these attempts

haA^e not been successful on account of a lack of knowledge of the

fimdamental physical effects which are involved.

At the request of the teclmical staff of the Army, this Bureau has

undertaken an investigation of the possibilities of this method. It is proposed to study particularly the relation between the phase of

the induced current and the position of velocity of the shell. Blast Investigations.—Throughout the year the Bureau has con- tinued the measurement of the characteristics of the blast of largo

guns for the Navy, but since other lines of work have seemed more

urgent this work has not progressed as rapidly as was desired. An

electromagnetic blast meter has been designed and built, and pre- liminary tests are being made at the Bureau preparatory to testing it under service conditions at Indian Head Proving Ground.

Timing Device.

In the study of the method of determining ejection velocities, a

special timing device, with which an electrical oscillograph may be
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 57

equipped, has been developed. Tests of this device show that by its use time intervals may be determined to an accuracy of a few millionths of a second. While the method was developed for a particular purpose, it is applicable to the .measurement of any small

time interval which it is possible to record electrically.

Submarine-Mine Investigations.

Improvement of Mine Detonators.—At the request of the same

bureau, the study of possible improvements in a special type of mine

detonator was undertaken late in the year. Protection of Ships Against Mines.—At the request of the Navy

Department, one of the representatives of the Bureau, while in England, visited the mine-sweeping fleet to make some experiments on a method which was in use for the electrical protection of the mine

sweepers engaged in the removal of the North Sea mine barrage.

A satisfactory method of protecting the ships themselves had been

devised, and it was desired to extend the method so as to protect

the sweep wires also. Difficulties inherent in the method made this

extension impracticable.

Hydraulic Machine-Gun Synchronizing Gear for Airplanes.

At the request of the War Department, a detailed study was made

of the factors which are of importance in hydraulic methods of

synchronizing machine-gun fire in airplanes. In this work it was shown that there is an appreciable time interval required for the

transmission of the energizing pulse in the tube of liquid which is used to fire the gun. The fact that such a time interval is unavoidable in any hydraulic or other mechanical control system limits the

application of such devices and is a strong argument for using an

electrical system such as that mentioned above, in which the time

required for the action of the control gun itself can be made very

small.

Special Muzzle-Velocity Measurements.

At the request of the Army, measurements were made of the velocity of bullets fired by centrifugal guns which were under test at the Bureau. The measured velocity agreed quite closely with the theoretical velocity. Measurements were also made of the muzzle velocity of a captured German automatic antiaircraft gun of 2-centimeter bore, using regular German service ammunition.

Study of Recent Scientific Developments in France and England.

The chief of the section spent April, May, and June, 1919, in

France and England studying scientific developments which have

occurred during the war, especially the improvements in ballistic instruments. Both the Army and the Navy cooperated heartily;

they extended every courtesy and in many ways showed their appreciation of the studies which were being undertaken. All of the important scientific laboratories doing research work along ballistic lines were vistited. In addition many observations of general scientific interest were made. A report covering this trip is in preparation.
58 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

ELECTRICAL MEASURING INSTRUMENTS.

(Testing and development of electrical instruments, meters, and ignition apparatus.)

Testing of Electrical Instruments.

The volume of testing for outside parties was very much reduced

by the war, but the testing for Government departments was greatly

increased, so that the total number of instruments tested was larger

than in previous j'ears.

The testing of instrument transformers had to be discontinued

during the war because of the departure from the Bureau of members of the staif who had previously been engaged in this work. This

class of testing has been resumed in the last few months. The accurate testing of these transformers is of increasing importance on

account of their use in measuring electrical energy, especially where

it is sold in large quantities or at high voltages and the Bureau has

consequently given special attention to the development of methods

and equipment for testing them.

Electrical Tests of Gasoline-Engine Ignition Systems.

The demand for routine tests of ignition apparatus reached a maximum last autumn and has since decreased, but requests for tests are

still being received from manufacturers at the rate of about four

per month.

The investigational work on spark plugs as first planned has been

completed except for measurements of temperature conditions in air- craft engines. This latter work has been held up for lack of both

staff and available engines. The porcelain developed by the Bureau

is now in regular production by the largest spark plug manufacturer

in the country.

The use of a subsidiary gap in series with a spark plug was studied

experimentally, and a preliminary report has been issued showing

the advantages and disadvantages of this device.

Considerable stud}^, both theoretical and experimental, has been

made of the operation of the high-tension magneto with a view to developing a working theory on which to base a logical design of

such apparatus. Particular attention is being paid to the effect of

secondary capacity and eddy currents, and methods are being de- veloped to measure these effects quantitatively.

A series of 15 reports have been issued covering various phases

of the ignition work. These reports will be printed in the Fourth

Annual Eeport of the National Advisory Committee for Aeronautics.

At the request of the Motor Transport Corps specifications for

spark plugs have been prepared to serve as a basis for their purchase.

Considerable time has been spent in cooperation with the areonautic engine-design section in developing a method for measuring the

velocity of flame propagation in the cylinders of internal-combustion engines. This method, which records the time of passage of

the flame oscillographically, gives good promise of success and an

extensive program of work has been laid out for it.

Electrical Trucks and Tractors. At the request of the War Department, the Bureau cooperated

in comparative tests of a large variety of electrical trucks and trac-
BEPOET OF DIEECTOR OF BUEEAU OF STANDAEDS. 59

tors for use in Army warehouses. The records of these tests were worked up and reports issued by the Bureau on the basis of which

the Purchase, Storage, and Traffic Division has prepared specifications for the purchase of such equipment.

Turret Fire-Control Apparatus.

A study of the electrical target turret indicators used in controlling

the fire of battleship turret guns was begun last year in an attempt

to find the causes of errors which sometimes occurred in the indication of the apparatus. This investigation was continued this year, and after a thorough study of the operation of the apparatus at various speeds, changes in the equipment, which it was believed

would remedy the defects, were suggested to the Navy Department

and to the makers of the apparatus.

Blasting Caps.

At the request of the Engineer Corps, a study was made of the time

required to fire electrical blasting caps used in setting off mines, gas

projectiles, etc., with a view to determining the possibilities of firing! a number of such caps in series. About one hundred caps were

fired under various conditions and the time recorded by the oscillo- graph.

The study of blasting machines mentioned in last year's report has

led to the development of a new type of machine having ovei" 10

times the capacity of the older type and slightly less cost and weight.

Radio Generators.

Considerable time was spent in planning and supervising tests of

900-cycle generators for use in airplane radio sets. The work consisted in obtaining characteristic curves, efficiencies, etc., of a number of generators under various conditions. The observations were made by enlisted men of the Signal Corps, but the planning of the

work and preparation of reports was under the direction of the

Bureau.

Cooperation with American Institute of Electrical Engineers,

At the request of the Instruments and Measurements Committee of

the American Institute of Electrical Engineers, the preparation of an exhaustive paper on "The accuracy of Commercial Electrical

Measurements" has been undertaken. This work is well under way,

and the paper will probably be delivered at the institute meeting in

the autumn. A considerable amount of time has also been given to assisting in the revision of the American Institute of Electrical Engineers Standardization Rules, and many errors and inconsistencies in

the older edition have been eliminated.

New Apparatus for Electrical Instrument Testing.

An attachment is being developed for use with the deflection potentiometer which serves to plot automatically the corrections of thei instrument under test, thus avoiding all numerical computations.

When a set of standard shunts designed to accompany this has been

built, the time required in instrument testing will be materially!'

reduced.

A new form of variable resistence has been constructed for use in

testing current transformers and is now ready for final adjustment.
60 EEPOBT OF DIRECTOR OF BUREAU OF STANDARDS.

The use of this will reduce the labor of such tests by at least 30 per

cent. Ignition of Cotton by Electric Sparks.

At the request of the Department of Agriculture some experiments were made on the ignition of cotton by electric sparks and on the

generation of electrostatic charge by the passage of cotton through

iron tubes. This request was occasioned by the frequent fires which

occur in cotton gins apparently as a result of static discharges. Thel

results obtained indicate that this is a very real fire hazard and that

the fire risk in gins can be materially reduced by proper electrical

grounding of the metal parts of the machinery.

MAGNETIC MEASUREMENTS.

(Measurement of magnetic properties of materials ; design and calibration of magnetic

instruments and appliances, including compasses ; magnetic analysis.) General Magnetic Measurements.

In addition to the routine testing of the magnetic properties of

materials, the work of the section includes the experimental study of

various methods and instruments for making magnetic measurements.

Such a study is nearly completed on a new type of permeameter

(the Fahy Simplex), which has recently been put upon the market.

The results so far obtained indicate that the instrument is convenient

and rapid and has an accuracy which is satisfactory for most commercial and research purposes. The instrument requires only a

single specimen, and there are no compensating adjustments to make.

Magnetic Analysis.

For a number of years work has been under way at the Bureau

in the development of methods and apparatus for using the magnetic properties of materials as an indication of their quality and

mechanical properties. The results of this work and the growing

interest of manufacturers of steel products justify a systematic general study of the subject for the purpose of determining to what

extent magnetic analysis can be utilized both in research and for

practical testing on a commercial basis. The method promises to be

very useful for the detection of inhomogeneities and flaws, for the

detection and study of physical and chemical transformations which

take place in iron or steel on heating or cooling, and for the estimation of the physical condition and the prediction of mechanical

behavior of steel and steel products.

During the past year a comprehensive program has been started

which consists of three distinct though closely interrelated parts:

I. Study of the fundamental relationships between the magnetic

properties and the physical structure and mechanical properties of

various types of steel by means of accurate magnetic and mechanical

tests on specially prepared samples.

II. Development of special apparatus and methods for making

magnetic tests on various forms of steel objects. III. Development of a number of direct practical applications for

the purpose of demonstration.

In this work the magnetic section has the cooperation of a number

of commercial organizations as well as of other sections of the

Bureau.
EEPORT OF DIRECTOR OF BUREAU OF STANDARDS. 61

Rifle-Barrel Steel.—An investigation has been completed and a paper is in press on " The Testing of Rifle-Barrel Steel for the Detection of Flaws." This investigation was made in cooperation with a large manufacturer of rifles. The results of the work indicate that

the magnetic method will surely detect flaws, but that other causes may render the material nonhomogeneous along its length when it

is not necessarily unfit for use. In view of this fact it seemed desirable to study further the possibilities and limitations of the

magnetic method, and in this work the Bureau has the valuable co- operation of the Technical Staff of the Ordnance Department. The

construction of special apparatus for this investigation is under way.

BaU-Bearing Races.—The development of a magnetic method

for the testing of ball-bearing races which was interrupted during

the war has been resumed in cooperation with one of the large manufacturers of ball bearings. It is proposed, if possible, to develop a method which will be commercially practicable for the determination

of hardness and the detection of cracks or soft spots.

Correlation of Properties.—An investigation has been started for

the correlation of the magnetic properties with the micrographic

structure and mechanical properties of a carbon steel of eutectoid

composition. Accurate tests will be made on standard test pieces

after various heat treatments. Information of this kind is fundamental to the development of magnetic analysis and the investigation

will be extended to include the study of various types of steel. Miscellaneous Prohlems.—In addition to the above investigations a number of less-extended experiments have been made to ascertain

the applicability of magnetic analysis for the inspection of various

articles, including welded ship plates, airplane tie wire, and rifle-bar- rel forgings. Most of this work was not completed owing to the

fact that with the ending of the war the necessary funds and facili- ties were no longer available.

Magnetic Compasses.

Most of the work on magnetic compasses during the year consisted

of cooperation with various branches of the military service. In

addition to work on testing of airplane compasses, which consisted

of testing a small number of instruments for the purpose of checking

the field inspection, a number of special investigations were made

covering various points of compass construction. These investigations included the development of a suitable process for aging compass magnets and a test for aging, a study of the relative merits of

platinum and stellite for pivots, and a study of the relative behavior

of natural and artificial jewels for pocket compasses.

A collection of a number of types of airplane compasses which

will be valuable for further study has been made.

PHOTOMETRY AND ILLUMINATING ENGINEERING.

(Maintenance of photometric standards, calibration of standard lamps, development of methods of photometry, inspection and life-test of electric lamps, problems in the utiliza.- tion of light.) Military Searchlight Investigations.

On account of the importance of searchlights in modern warfare

and the need of more Imowledge of their characteristics and performance, the Searchlight Engineering Section of the Four Hundred and

Eighty-eighth Engineers requested the Bureau to cooperate with
62 REPOET OF DIRECTOR OF BUREAU OF STANDARDS.

them in the investigation and testing of searchlights. The work was

begun in March, 1918, and continued until January, 1919. The in- vestigations included the following:

Distribution of Light from the Bare Arcs.—Light distribution in

several planes through the arcs without mirrors was measured in the

laboratory. Seventeen arcs of various types and conditions were measured in this manner. From these measurements information was obtained as to their effectiveness in various searchlight mechanisms. The tests were also useful in giving data for specifications for

searchlight carbons.

Distribution of Light in the Searchlight Beam at Various Distances.—A great many tests were made to determine the distribution

of illumination in the beam. The most of the tests were made at a

distance of 930 feet, 20 lamps being so measured. In addition, other

measurements were made at various distances up to 5 miles.

Absorption of Light by Front Glass of the Searchlight.—A number of tests were made to determine the amount of light lost by

absorption, reflection, and scattering of light by the front glass, and

by devices for limiting the Deam and avoiding stray light.

Photometric and Illumination Investigations for Military Departments.

Daylight Signaling Devices and Special Lamps.—A great deal

of time was spent in a study of daylight signaling lamps and lamps

for signaling from airplanes at night, this work being undertaken at the request of the Bureau of Aircraft Production. Daylight signaling tests were carried out over ranges of one-half, 2, 3 and 5 miles

to determine the magnitude of the intensities required. Many tests were also made to determine the increase in beam efficiency due to partial silvering of lamp bulbs used in the signaling devices.

Protective Fence Lighting.—In September, 1918, the Bureau was

requested to make a comparative test of various floodlight projectors

for protective fence lighting. The tests were carried out with the

cooperation of the Ordnance Department and resulted in the recom- mendation of the use of angle reflectors throwing the light at right

angles to the fence instead of floodlights throwing the light parallel

to the fence, as the tests showed that the smaller reflectors were

superior to floodlights for the type of service required. The signing

of the armistice stopped purchases of such equipment, but the results of this investigation will be of assistance in the future design of protective lighting installations.

Acetylene Generators.—Last year several months were spent in an

investigation of the performance of numerous types of portable

acetylene lights, with particular reference to their suitability for

military use at the front. This investigation was originally intended

simply to give information on which a choice between the various

types of lights could be based, but it developed that many of them

had certain features which made them unsuitable for use under the

prescribed conditions. Consequently the makers were consulted, and

a number of modifications suggested by the Bureau were made in

the lights.

During the present year, as a result of a controversy over the

merits of one of the lights recommended as a result of the above in- vestigation in comparison with a new type developed for Army use,
EEPORT OF DIRECTOR OF BUREAU OF STANDARDS. 63

further investigation was requested, and extensive tests were carried

out, particularly to determine the reliability of operation of the

lights. The results obtained fully confirmed the earlier recommendations of the Bureau.

Miscellaneous Tests.—In addition to the special investigations

outlined above, numerous acceptance tests of kerosene and signal oils,

reflectors, luminous flares, star shells, etc., were made. To assist military departments in the design of instruments and apparatus many

lamps were photometered and illumination instruments calibrated.

Standardization of Screens for Measurement of Brightness of Radioactive Materials.

The measurement of the absolute brightness of radioactive, self- luminous materials has become commercially important because of

the greatly increased use of such materials in recent years. This

work is handled by another section (see report below) iDut the photometry section has been called on for the calibration of colored

screens which are used to make the light from electric lamps comparable in color and intensity with the luminous materials. Such

screens have been standardized for the Bureau of Mines as well as for this Bureau.

Inspection and Life Tests of Incandescent Lamps.

Orders for about 4,225,000 incandescent electric lamps were placed

by departments of the Government during the year. Of this quantity about 75 per cent were large tungsten, 13 per cent carbon, and

12 per cent miniature lamps. Six per cent of this total were ordered

shipped without inspection, whereas during the previous year about

20 per cent were so ordered from a quantity approximately twice as

great. Actual inspections by this Bureau during the year, including

lamps delivered on orders last year, approximated 5,100,000, of

which about ,4,000,000 were large tungsten, and the remainder carbon

and miniature lamps in about equal quantities. This represents an

increase of about 40 per cent in inspection over last year. The initial inspection made at the factories covers the mechanical

qualities of the lamps and their rating with regard to power con- sumption and efficiency. In order to pass a final judgment on the

quality of the lamps it is necessary to have actual burning tests, and when the initial inspection is made samples are selected for

such tests, which are called " life tests." During the year life tests were completed on 2,683 vacuum tungsten, 152 gas-filled, and 373

carbon lamps. Eecords of these tests were kept separate for each

month of manufacture in order to compare results with those obtained in current tests of the product made at the factories. It was

found that gas-filled lamps, which are now included in the standard specifications, considerably exceeded the life requirement, and,

following the usual practice, one of the large manufacturers has

improved efficiencies to take up a great part of this excess life. Efficiencies of vacuum tungsten lamps are also undergoing a gradual

improvement.

Work of considerable importance was done by special inspections

and tests of lamps for the General Supply Committee in connection

with bids for supplying lamps under contract for the fiscal year

1920; data regarding the quality of lamps which some of the new
64 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

bidders proposed to furnish were obtained as a result of these tests, and served to guide the Supply Committee in placing the new contracts. While the specifications for large lamps are in a very satisfactoryform, and the efficiency and performance of these lamps are well

established, there is little available information with regard to the

general commercial quality of miniature lamps such as are used in

flashlights and in automobile and similar lighting equipment. As a part of the standardization work in which the Bureau assisted the

War Department during the year, tentative specifications for some

types of miniature lamps were drawn up and agreed upon with representatives of the manufacturers, but on account of the lack of

information as to the limits which could reasonably be fixed for

efficiency and life of such lamps the specifications could not be

made very strict. Apparatus for making life tests of miniature

lamps has now been designed, and the component parts have been

purchased. It is expected that this equipment will be installed

in time to carry on regular tests on the lamps bought on Government

contract during the coming year. Illumination Surveys of Commerce Department Buildings.

At the request of the Secretary of Commerce an illumination survey

of the main building of the Department of Commerce was made.

The average illumination in the offices was found to be about 2.5 footcandles, which is considered the lowest allowable intensity for office work. It was shown that the existing level of illumination could be

maintained by substituting more efficient lamps of a lower wattage,

making the connected load 30 per cent less, or that the substitution

of more efficient lamps of equal wattage would make the intensity

about 4 foot-candles, a value more in conformity with good practice.

Some surveys were made in the Coast and Geodetic Survey building and advice given for the material improvement of the lighting in

certain special cases. Pressure of other work has prevented a complete analysis of the lighting of all Commerce Department buildings,

although preliminary inspection shows that there is room for improvement in several of them.

RADIO COMMUNICATION.

(Maintenance of standards and development of methods of measurement at radio fre.- quencies ; investigation, standardization, and improvement of instruments and methods of radio communication ; investigation of the properties and uses of vacuum tubes.) Development of Radio Work of Bureau.

There has been a great expansion of the work of the radio section

during this year. The section moved into its new building in October. This change was made the occasion of increasing the equipment

and establishing permanent set-ups for testing and for other work

involving measurements of a more or less routine nature. The re- search program has been largely prepared with a view to cooperation

with the Signal Corps and Navy Department. For the period of

January to June of this year the investigations have been almost

entirely work that was undertaken for the Signal Corps.

During the summer of 1918 the section was fortunate in obtaining

the services of a number of men of special qualifications from various
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 65

universities and technical schools who assisted most effectively, particularly in the preparation of the radio textbook mentioned below.

For special work of other kinds the section had the advantage of the

services of a number of soldiers detailed by the War Department,

assisting particularly in the work on vacuum tubes, oscillographic

measurements, and testing.

The work of the section is developing into the general field of elec- trical communication. The methods and instruments of high and

low frequency communication are coming to have much in common,

and the future promises much in the way of the utilization of the

intermediate frequencies which have hitherto been little used. This

development is largely due to the vacuum tube and the general study

of high-frequenc}^ measurements.

Electron Tubes.

An investigation of three-electrode vacuum tubes or electron tubes

has been undertaken on a considerable scale. The first work in this

field was va aium-tube standardization for the Signal Corps. Later

a number of specific problems in this field were undertaken for the

Signal Corps and the Navy. The work has been furthered by conferences held at the Xavy Depai'tment between the Government departments concerned and the manufacturers of the tubes. Apparatus and methods have been develop :d to determine the principal constants and to study the uses of electron tubes as generators,

detectors, amplifiers, and modulators. The principles involved in the

functioning of these tubes have been studied; for example, one piece

of work has been a theoretical study, verified by experiment, of the

calculation of the constants of tubes from their dmiensions. A criti- cal study has been made of the Signal Corps testing sets for measure- ments upon electron tubes, and improvements in the sets have been

suggested.

Sjjecial study has been given to the subject of tubes for generating

alternating currents, commonly called " power " tubes. The investigation has had the very satisfactory result of developing a method

for calculating the power output from the characteristics of the

tubes. This investigation also included a study of the harmonics in

power-tube circuits, in typical cases. The dependence of the harmonics on the resistance and reactance of the high-frequency circuit

has been determined, and means of calculating the harmonics of the

high-frequency current from the form of the pulsating-plate current have b en devised. The use of large power tubes has been studied, one of the principal problems being the development of a source of

the direct voltage needed for supplying power to the tubes. The use

of the large tubes as amplifiers has also been studied. This work

has direct applications to the development of practical systems of

radiotelephony.

The dete.tor action of electron tubes has been made the subject of

a special research. Methods and apparatus for measurement of the

det ctor action have been developed. The detector sensitivity of

typical tubes has been measured under varying conditions, and the

theory of detector action has been worked out. A considerable contribution to the fundamental design of amplifiers was made in an investigation of the input impedance of electron

142289—19 5
66 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

tubes. The Signal Corps had found in practice that the constants

of the output or plate circuit of a tube affect the apparent input impedance. This complicated the design of amplifiers in which tubes

fed successively into one another, and, in fact, made the prediction of

performance of any given amplifier circuit practically impossible.

The solution to this problem of the effect of the constants in the

output circuit on the input impedance was worked out theoretically,

and a very satisfactory experimental verification was obtained. This

work greatly facilitates the design of amplifiers and gives a better

understanding of the operation of electron tubes. Coil Aerials.

Experiments have been continued on the development of the coil as an aerial in place of the ordinary antenna. Methods of measuring received current were devised and experiments made to check

transmission formulas and to assist in determining the fundamentals

of design of such coils. A detailed study was made of the resistance

of coils and methods of measurement thereof, and the results of meas- urements of resistance and other constants were coordinated with the

results of transmission experiments. These experiments were made

• on coils of varying dimensions, numbers of turns, etc. A general paper was prepared on the principles of this subject, dis- cussing the nature of electric waves and radio transmicsion and i"e- ception, giving transmission formulas for either antenna or coil aerials, and discussing the fundamental principles of design and

measurement of the antenna effect in coil aerials and of radiation

resistance.

A study was made of the accuracy of determination of direction

with a direction finder as affected hy various kinds of objects in the

vicinity. With nonmetallic bodies, such as a tree, a brook, or a bank

of earth, the distortion or change in observed direction became negligible at a distance equal to the largest dimension of the object.

With objects constructed in whole or in part of metal, such as a bridge, water tower, or the Washington Monument, the distortions were very large and changed greatly with wave length. It was con- cluded from the experiments that a direction finder must be kept at

least 300 feet away from such objects.

An ajDparatus for determining the absolute direction, as well as

line of direction of a radio wave, was developed. The device utilizes the capacity of the coil structure to ground, an inductance in series with this capacity being tuned to the same frequency as the coil circuit. Field experiments showed that the device determines absolute

direction satisfactorily. It is, however, somewhat difficult to use,

since, like other similar methocls which have been developed for unidirectional observations, it requires sensitive adjustments.

- Signaling System for Airplane Landing.

Experiments originally requested by the Air Mail Service of the

Post Office Department have been in progress to develop a method

to enable an airplane to find its landing place in fog or in the dark.

The Signal Corps has recently taken an interest in this problem, and

the method may be of use for Signal Corps purposes. The object in

view has been attained by two general methods. In both a large coil

is wound on the landing field and a receiving coil is placed on the

wings of the airplane. In one method low-frequency current of 500
KEPORT OF DIRECTOR OF BUREAU OF STANDARDS. 67

or 1,000 cycles per second is passed through the coil. In the other

radio-frequency current is used in the coil. By these methods it has

been possible to receive signals with an airplane 6,000 feet in the air. The system has the desired characteristic that the signal falls off rapidly as the landing field is left. The transmitting coils used have

varied from a size 80 by 200 feet to a size 1,400 by 2,500 feet. A large

amount of experimentation has been necessary to determine the

proper constants of the transmitting and receiving systems and to determine the characteristics of the method at the various frequencies

tried. Submarine Radio Communication.

Satisfactory methods for communicating with submerged submarines have been urgently needed, and two members of the Bureau

staff spent several months during the summer of 1918 at the New

London submarine base developing the application of coil aerials for

this purpose. Very satisfactory results were obtained. With a

single-turn coil or loop attached to the outside of the submarine, signals could be received as well when the submarine was submerged

as when on the surface. It was also possible to transmit from a submerged submarine a distance of 12 miles. It thus becomes possible

for a ship and submarine to exchange recognition signals. A coil aerial is a satisfactory direction finder when submerged and readily

receives signals transmitted thousands of miles just the same as when

used in air. The Navy Department considers this the best work

which has been done on submarine radio and has equipped the larger

svibmarines with the apparatus which was developed by the Bureau's

experimenters.

Insulating Materials.

The investigation of insulating materials carried on this year has

been limited mainly to the laminated materials of the phenol or bakelite type, such as are used extensively in making electrical, and particularly radio, apparatus. The electrical properties measured are power loss and dielectric constant at radio frequencies, flash-over

voltage and volume, and surface resistivity. The tests of mechanical properties which were made in othsr sections of the Bureau and

for which the samples were cut and the work given general supervision by this section included tensile and transverse strength, hardness, brittleness, permanent distortion, thermal expansivity, density,

and moisture absorption. Methods of measuring the effects of high

voltages at radio frequencies on the materials were developed. The

methods of measuring power loss or phase difference at radio fre- quencies were improved and a cabinet generating set especially

adapted to this work was constructed. Minor improvements were

macle in the methods of measurement of various properties. The re- sults of measurements indicate, in general, that these materials are

susceptible of improvements and that the product of a particular

manufacturer varies more from time to time than the products of the

several manufacturers differ from one another. The manufacturers

and some of the users of these materials have shown an unusual in- terest in the investigation, and there is every prospect that this in- vestigation will constitute an interesting line of research for some

time to come.
68 KEPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Radio Measurements.

High-frequency oscillographic equipment has been developed.

Three cathode-ray tubes were constructed and the auxiliary pumps,

ovens, etc., provided. One of the tubes is of the hot-cathode type,

having movable electrodes, so that a most efficient design can be

determined. The equipment has been applied to demonstrations of

the steadiness of vacuum-tube generators, to the testing of quenched

gap transmitters, and to research on generating vacuum tubes. A study was made of the production, measurement, and utilization

of high voltage and large current at radio frequencies. A vacuumtube equipment, consisting of six large power tubes, was developed

for this purpose. A voltage of 48.000 volts at radio frequencies

may be applied to samples of insulating material, and currents of

100 amperes at radio frequencies may be produced for the testing of

ammeters. A study has been made of the measurement of radio

frequency resistance. A variable resistor for radio frequencies was

developed, a study of the precision of measurement made, and

sources of error investigated. The study of resistance measurement

at radio frequencies is j)articularly important, since such measure- ment gives the means of determining a number of quantities, as, for

instance, wave form and power.

An investigation was made to determine whether a crystal detector

could be developed having a permanent contact. The methods tried

in the effort to secure a sensitive, permanent contact detector included

alternating-current electrotysis, cathode sputtering, direct-current

electrolysis, soldei'ing, arcing, spark welding, and mechanically maintained contact. The latter method gave a thoroughly satisfactory

detector, but the genc;-al conclusion of the investigation was that the

sensitiveness of the best ci'vstal detectors depends upon the existence

of an imperfect contact. The use of a grounded shield in connection with measuring cir- cuits Avas developed. There has heretofore been no method of protecting the complete radio circuit from troublesome stray electro- motive forces, in the way that, for instance, a condenser is protected

by its shield. It was found that a shield in the form of a grid of

wires between the generating and measuring circuits improved the

steadiness of the deflection and the precision of measurement a very

gx'eat deal. A shielded cage for the inductance coil of the measuring

circuit was also developed, so that the entire circuit can be thoroughly

shielded.

Radio Textbook.

One of the principal accomplishments of the year was the production of a genei'al textbook to be used in training engineers and operators in the fundamental principles of radio communication. The

publication of Circular 74, " Eadio Instruments and Measurements,"

and the furnishing by the Bureau of additional material for use in instruction worlv led the Signal Corps to request the Bureau to pre- pare a general textbook of radio communication for the training

of radio electricians in the Student Army Training Corps and in the

field signal battalions. By the concentrated effort of several members

of the staff, ably assisted by a number of specially qualified teachers

from various schools, the book was prepared in three months. It has been printed as radio Pamphlet No. 40, of the Signal Corps, with
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 69

the title, "The Principles Underlying Eadio Communication," and

has been most favorably received as being simple, intelligible, and

nonmathematical, althoiigh giving an accurate and I'airly complete

discussion of the fundamentals of radio work.

SOUND RANGING.

(In normal times the staff of this section is engaged in tlie study of electrolysis and re- lated problems. During the war nearly all of the staff of the section were assigned to various military problems, especially sound ranging.)

During the year 1917-18 a large amount of time was gis-en to the

study of methods of locating hostile batteries by recording electrically

the times at which the sound of a discharge reached a number of sta- tions. After comparing the merits of various systems in use, the

Bureau undertook to impiove the equipment of one type used by the

French Army, which appeared most promising. As stated in last year's report, the equipment developed at the Bureau was sent abroad

for trial at the front under the direction of two members of the staff who Avere commissioned for this work, but the plans for this trial were

defeated b^^ the death of the senior officer, Capt. Ernest Weibel, from

injuries received v^'hile on duty at the front. On the basis of such information as could be obtained from the

front and from field tests at the Winthrop Proving Ground, the development of the equipment was pushed actively until the final apparatus was believed to be definitely superior to any other equipment in use. Besides other advantages, the Bureau's equipment was capable of

being made up in mobile sets, and thus promised to be especially valuable in the type of warfare Avhich developed during 1918. Sets were

sent to France and to Italy, and two more members of the staff had

just gone over to put them into operation Avhen hostilities came to a

close. At the request of the War Department, work was continued for some weeks after the armistice was signed, in order to complete the

sets then under way, and it is understood that when the reorganization of the Army is completed the cooperation of the Bureau will

again be desired in deA'eloping a standard type of sound-ranging

equipment.

ELECTROCHEMISTRY.

(Electrochemical problems, particularly those involved in the study of electric batteries,

electrical properties of c'lemical compounds, the silver voltameter, and other investigations in electrical measurements.)

Dry Cells. The circular on dry cells mentioned in the report of last year was

completed and published as Circular No. 79. It describes the various

sizes and kinds of dry cells, the electrochemical principles involved,

and the service which may be expected fi'om dry cells of various sizes. As an appendix to this circular, specifications for dry C3lls are given

Avhich were written at the Bureau and have been formally adopted by

the War Department.

A large number of tests have been made for the military depart- ments. The Signal Corps reauested an investigation of small batteries for use with radio amplifiers because of the poor servics which

they had been giving. Six hundred and sixty-four of the batteries

of the type Ba-2 were tested at the Bureau, and nearly 2,000 in the
70 BEPORT OF DIRECTOR OF BUREAU OF STANDARDS.

military storehouses. In addition, over 400 of the type Ba-5, which

is similar in size but arranged for the addition of water at the time

the battery is required for use, were submitted for test. The causes

of failure of the cells were determined and methods of improving the

service were indicated. A larger type of battery for the same purpose was adopted by the Navy Department in accordance with suggestions

made by the Bureau, and this type has also been tested in large numbers. Several tests of batteries for use with a trench-signal projector were made for the Bureau of Aircraft Production, and a considerable

amount of material for the manufacture of dry cells, intended for

shipment to French factories and. the overseas j)lant of the Signal

Corps, was analyzed and tested. Samples of batteries intended for

use in submarine mines were tested for the Navy Department and an

examination Avas made of dry cells taken from a captured German

mine.

The tests of dry cells for the military departments have been

special tests in most cases. For the regular commercial testing of

dry cells apparatus to control the tests automatically was deemed

desirable, since the cells have to be subjected to alternate periods of

discharge and recuperation, and for this purpose a control mechanism has been designed and constructed in the Bureau's instrument

shop. This apparatus is believed to be superior to any which has

previously been used, since one relatively sim.ple piece of apparatus

is capable of controlling a number of different tests at the same time,

while the equipment which has been in use at various manufacturing

plants is generally complicated and can make only a single test. The

work of installing this apparatus was begun at the close of the fiscal year. • A large amount of work has been done in studying methods for

dry-cell analysis. This involved a comparison of all the available

methods for determining the various constituents of dry cells and the

selection of those best adapted to battery problems. The methods

Avhich were selected have been prepared in the form of a manual that can be put in the hands of a routine worker.

The tests which were made for the military departments showed

the need of systematic study of the causes of deterioration of dry cells when not in use and of means for obtaining a satisfactory " shelf life " of cells. This was undertaken during the latter part of the fiscal year. The following lines are considered the most important parts of

this research: (1) Measurements of the conductivity of powdered

manganese-dioxide ores with reference to the size of tlie particle and

the intercomparison of ores from various sources; (2) the corrosion

of zinc by electrolytes containing various concentrations of am- monium chloride and zinc chloride; (3) the potentials of the manganese-dioxide electrode in solutions of varying hydrogen-ion concentrations; (4) the measurement of the hydrogen-ion concentration

in various dry cells; (5) the making of limited numbers of dry cells at the Bureau from materials of which the chemical and physical

properties have been studied. Much of this research is made neces- sary by changes in sources of supplies obtainable by the manufacturers which have resulted from the Avar. At the request of the Signal Corps, an investigation of the galvanic

pile was begun to determine the possibilities of its use where only

small currents are required. The Bureau deA'eloped a disk cell, con-
REPOKT OF DIRECTOR OF BUREAU OF STANDARDS. 71

taining the ingredients of a dry cell, which compared favorably with

the type Ba-5 batteries and avoided the principal source of failure

which was found in them. Investigation has also been made of galvanic piles in the form of zinc-copper and zinc-carbon couples.

In connection with the efforts of the Food Administration to conserve foodstuffs the Bureau was asked to render a report on the use of wheat flour in the manufacture of dry cells. It was recommended

that the manufacturers be permitted to use wheat flour unfit for

human consumption, and this recommendation was acceptable to both

parties.

Storage Batteries.

An extended test of storage batteries for the propulsion of electric

trucks and tractors was made for the Construction Division of the

Army. Measurements of the capacity and efficiency under various

conditions were made on batteries submitted by all the principal

manufacturers, and the speed and acceleration of an electric tractor when equipped with batteries of the lead-acid and of the iron-alkali

types were determined under service conditions. After the report on this test was submitted to the War Department, the Bureau was

.requested to continue the investigation to obtain additional information needed in the preparation of adequate specifications for tractor

batteries. An extended series of measurements was made on the more important types of batteries, and the Bureau assisted in the

preparation of preliminary specifications.

A test of the drying of wood separators in batteries shipped and

stored without electrolyte was made for the Motor Transport Corps.

A number of extended tests, involving the analysis of acid and

alkaline electrolytes for storage batteries, were made for the Signal

Corps and the Panama Canal. These tests involved an extended

study of the methods available for the analj'sis of battery acid, particularly with reference to the determination of nitrates and nitrites

and other impurities which, if present even in small amounts, have

a, deleterious effect on the storage battery. The methods of analysis

which were found best suited to the battery problems have been pre- pared in the form of a manual. Considerable research was also necessary for the analysis of the alkaline electrolytes, this being a more unusual problem than that of the acid analysis. The Bureau

has collected from manufacturers and large users of storage batteries the specifications for battery acid and finds that the amounts of

certain impurities permitted by these specifications vary by 1,000

per cent. As no reliable information is available on the effects of

many impurities which are often present in battery acid, a series of

^experiments to determine these effects was begun and carried on during the year. Methods for measuring the single potentials of the plates in stor- age cells have been studied, since this is a valuable method of testing

the batteries. It has involved a comparison of a number of different

half-cell electrodes and a series of experiments on the cadmium

electrode which has been used in a limited way for many years. In

this work the errors to which the cadmium electrode is subject were

determined, and it was found that by a slight change in the ordinary

procedure the more serious of these errors could be eliminated. A

series of questions sent to the different manufacturers and a search
72 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

of the literature on the subject shows that no reliable information

as to the use of this electrode and the errors to which it is subject

has been available in the past.

The Construction Division of the Army undertook the preparation

of a manual on tractor batteries for use in maintenan e stations.

Fundamental data for this manual were obtained at the Bureau during the te^ts which had been in progress. At the close of the fiscal year, the Construction Division requested the Bureau to assist in the

completion and publication of this manual, and it is to be published

by the Bureau as a cii'cular. The War Department Committee on Education and Special Training also undertook the preparation of a manual consisting of job

sheets for the instruction of the enlisted perscnnel and reserve officers in the operation and repair of storage batteries, and this Bureau was

requested to furnish information and to criticize the manuscript.

Railway-Signal Batteries.

During tlie winter a comparative test of different kinds of railwaj'^-

signal batteries was made, a number of them being subjected to out- door weather conditions. It was found that the perfonnance of some makes of these batteries varied greatly with the temperature, and

that the usual specifications for test do not make proper allowance

for this variation.

RADIOACTIVITY AND X-RAY MEASUREMENTS.

^lothods of measurement of radioactive materials and phenomena, standardization

an<^ measurement of radium, mpsot»iorium. radium preparations, and similar materials; study and measurement of self-luminous materials]) study and standardization of X-ray

apparatus and supplies, and the application of X rajs to various investigations.) Luminous Materials.

Self-luminous materials contain a small percentage of a radioactive material, usually radium, and require no previous exposure

to light to excite their luminescence. This property is of great value

in many fields, both military and civil. These materials are used for

the illumination of airplane dials of all kinds, of bomb sights, compasses of all kinds, gun sights, roimd counters for machine-gun

magazines, targets for indirect fire, dials for navigation instruments,

etc. In civil life they are used for the illumination of dials for

clocks and watches, for marking push buttons, pull sockets, signs in

dark/ places ; in fact, wherever a faint and entirely self-contained

illumination is desired.

When the Bureau began the study of these materials in 1916 but

little was known and nothing had been published concerning their

properties. In particular nothing was known regarding the effective

life of the material and but little data was available regarding the

brightness that is needed for various purposes. Both are of prime

importance in the practical use of these materials. After developing

suitable methods for measurement it was to these problems that the

Bureau directed its attention.

A considerable amount of data had been obtained by the time the

United States declared war with Germany. This was at once placed

at the disposal of the Departments of War and Navy, and from that

time to the present the study of problems of special interest to these
REPOET OF DIRECTOR OF BUREAU OF STANDARDS. 73

departments has largely supplanted the more orderly investigation

of the initial problems. Material bearing upon the latter has, however, been accumulated throughout this time and will be collated

with the earlier observations.

During the year cordial cooperation with the various branches of

the military cleiDartments of the Government has been continued.

This has included (1) the furnishing of information concerning the

properties of luminous materials and methods for measuring their

surface brightness, (2) recommendations regarding specifications

and estimates of cost, (3) the measurement of the brightness of se- lected articles, (4) the preparation and standardization of apparatus and supplies for the factory inspection of dials, (5) the detailed study of selected specimens, (6) the carrying out of miscella- neous experiments, and (7) the preparation of models of articles so designed that the brightness can be varied, by which much useful

information regarding the most desirable brightness is obtained.

Among those with whom the Bureau has so cooperated may be

mentioned the several divisions of the Bui-eau of Aircraft Production

and of the Ordnance Department, the Engineer Corps, and the In- ventions Se:tion, General Staff, Army; the Bureau of Steam Engineering, the New York Navy Yard, and the Bureau of Lighthouses.

Cordial relations with the manufacturers and civilian users of

these materials have been maintained. Many requests have been

received from the latter for information and aclvice. These ra- quests have been complied with as fully as possible, but many

pertinent and important questions concerning these materials are

still unanswered, and can be answered onlj^ by the careful work of an authoritative institution, such as this Bureau, that is able to carry on the work over a term of years. In addition to investigations of various kinds, routine tests of 418

luminous military articles and of 73 civilian articles were made.

One mimeograjohed circular was issued under the title, "Luminous

Material Circular No. RLC-6 " ; it contained information bearing

upon specifications for the illumination of articles, and in a slightly

modified form will be published by the National Advisory Committee for Aeronautics under the title, " On Self-Luminous Materials."

Standard Radium Solution.

Radium solution of known strength was furnished to the Walter

Reed Hospital for medical use. The public was furnished with 100 cubic centimeters of a dilate

solution of certified concentration; such solutions are used for the

preparation of standards of radium emanation. These standards

are necessary for the determination of the radium content of ores, waters, etc.. materials containing only a relatively small amoiuit of

radium or of radium emanation.

Radium Emanation Work.

When a material contains but a small amount of radium, its radium content is determined from the rate at which it produces

radium emanation. The latter is a radioactive gas produced by the

spontaneous disintegi-ation of radium.

Radium determinations by the emanation method have been m?de

for the Walter Reed Hospital and for the Bureau of Aircraft Pj-oduction.
74 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Gamma-Ray Measurements of Radium.

During the first lialf of 1918 tlie rate of receipt of radium for

measurement and certification was low. Since July, 1918, it has

increased rapidly. Until January most of the material was for ex- port and was intended for military use. Since January the rate of

receipt for certification of radium intended for vise in surgery and

dermatology has far exceeded all past experience of the Bureau.

During the year 474 preparations containing a total of 13,159

milligrams, and of a market value of over $1,500,000, were measured

and certified. Of this, 170 specimens, containing a total of 5,065

milligrams, were certified for export, 4,000 milligrams being intended

for military use. The preparations for export were distributed as follows

Country.

rnfland

France Japan

Brazil Kew Zealand

dumber.

Milli- grams

of radium.

2,347.9

l,71fi.3 673.5

130.6 70.2

Country.

Spam

Australia Fouth Afrifa Argentine Republic Canada

Number.

Milli- grams

of radium.

67.9

27 4

14.7

11.4

5.3

Since the initiation of its radium work the Bureau has year by

year certified radium for export, as shown in the following table,

the ratio of the amount certified for export to the total amount meas- ured during the same year being shown in the last column of the

table

Year.

Mili- grams of radium.

Fraction of

total. Year.

Milli- grams of radium.

Frac11 jn of

total.

914-15 285.5 Per cent. 27.9 ' 1918-19

fo 1,001.0

\i'4,065.2

Per cent. "7.6

1915-16 630.9

1916-17 369.7

357.1 5.7

1917-18 6.7 ! Total 6, 078. S

a Nonmilitary uses. 6 Military uses. X-Rays.

By costly experience roentgenologists have learned that the protection of themselves from X-rays is of utmost importance. This

protection is obtained by the use of lead and of lead-impregnated

materials, notably lead glass and lead rubber. When the Bureau began its study of these protective materials it was found that some

materials offered for protection were entirely worthless and few of

them were as efficient as desired. As stated in the report for last year, the Bureau has been markedly successful in securing an improvement in the quality of these materials.

The study and testing of protective materials has been continued

throughout the year, a preliminary determination of the effective

absorption of lead glass and of water for radiations of a type widely
REPOET OF DIRECTOR OF BUREAU OF STANDARDS. 75

Tised by roentjjenolo^sts has been made, and the applications of radio^rraphy as an aid to various investigations have been studied.

Investigations and tests have been made for tlie Bureau of Aircraft

Production, the Surgeon General's Office, and the Ordnance Department, as well as for other sections of this Bureau.

A paper treating- of the early work of the Bureau on protective

materials was published in the American Journal of Roentgenology

( Vol. V, pp. 472-478; 1918) under the title " Rontgen Ray Protective Materials.." On the invitation of the Western Ronto-en Society, a paper treating of the X-ray work and plans of the Bureau was

presented before that society at its amiual meeting in November.

Roentgenologists are thoroughly awake to the need for the study

and testing of all types of X-ray apparatus and materials and are

desirous that the Bureau take a commanding position in this work.

The many demands made upon the Bureau and the difficulties attending the reorganization of its work on a peace basis have prevented

the Bureau from giving to the X-ray work the support that it de- serves and requires, but it is hoped that means for remedying this

condition ma^^ be found in the near future.

PUBLIC-UTILITY STANDARDS.

Public-Utility Investigations.

A large and important field of work, including more of engineering and field work than most of the electi'ical work so far described,

is concerned with the various public utilities, particularly electric

light and power, gas, street railway, and telephone companies. The

work includes (1) scientific and engineering research, (2) the study

of public-relations questions, (3) the preparation of specifications

regarding the quality of public-utility service, (4) methods of testing

and inspection employed by municipalities and commissions, (5)

safet^^ rules for use by the utility companies to safeguard their employees and the public, and (6) the collection and distribution of

information by published papers and through correspondence.

This work is a natural outgrowth of the research and testing work

done by the Bureau of Standards for the public-utility companies for

several years. The testing of electrical instruments and meters, of

gas lamps and the standards employed in measuring the candlepower and heating value of gas. the life testing of electric lamps, the

testing of instruments used in teleiDhone work, research on electrolysis

mitigation, and similar investigations and tests connected with the

public utilities have all involved to a greater or less degree questions

of standards of service in the various public utilities. The Bureau

has gradually accumulated a considerable amount of infoi-mation on

these questions and has been able to contribute materially to the

establishment of standards of quality of ser^dce in several of these

lines. Furthermore, it has promoted with niarked success the practice of settling disputed questions in this field on the basis of sound

engineering and economic principles and of cooperation between in- terests rather than bv legal controversy, and in so doing the Bureau

has attained an enviable position as an impartial mediator in such

questions. Consequently, during the past two years, when abnormal
76 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

conditions haA^e given rise to many cases in which readjustment of

service standards or of rates has been called for, the public-utility

staff of the Bureau has been called upon for an unprecedented amount

of work.

Relation of Bureau to Municipalities and Public-Service Commissions.

In many States the public-service commissions have set standards

of service, and the Bureau has cooperated with most of those that

have done so. In other States the railroad or public-service commissions have taken no action in the matter, although having authority to do so. Again, in some States there are no public-service

commissions to issue regulations or to inspect the quality and safety

of the service rendered by the various utilities. In any case the

cities and towns must look after their own interests, in whole or in

part, and frequently have taken up such matters very successfully.

Even Avhera there -are well-equipped and active State commissions

which have adopted rules and are ready to hear complaints regarding rates or service, a very large responsibility rests upon the

municipalities. Few State commissions will ever be likely to have

a force of engineers and inspectors large enough to enable them to take the initiative in every case and relieve the municipalities of

all the responsibility. Oi\ the contrary, if the municipalities are

active and enterprising in their own behalf, and if the larger ones have well-equipi)ed public-utility departments which can prepare

the city's complaints or requests and take them up to the State commissions for hearing and adjudication, the State commissions will

be better able to serve all the municipalities of the State, and the

municipalties will enjoy in large measure the advantages as well as the responsibilities of home rule without its greatest disadvantages.

For most cities and many commissions it is a difficult matter to judge the quality of service rendered by its utilities. The studies

made by the Bureau are a great help in this connection, but much

remains to be done. It will conduce td fairness and good understanding to have the subject studied further and to have specifications as definite and complete as possible mado available for all branches of public-utility service.

Obviously, it will never be practicable or economical for any State

commission^ or city to handle these questions alone. Though they

possess large and able engineering staffs or employ specialists foi each separate problem, the question of what is good service oi whether the service in any given case is adequate, safe, and satis- factory can be settled only by reference to what is done under

similar circumstances elsewhere in the country. In other words,

standards of good practice and good service are largely determined

by general experience and should be. studied comparatively, using

the experience of the entire country. The Bureau has been doing

this for several years, and, although it has not been able to do as much as it would have liked to do, it has done enough to demonstrate the practicability and accei^tability of the method. The success and approval which the work has met so far fully justify its greater development. The work of the following five sections is largely in connection with public-utility problems:
REPOKT OF DIRECTOR OF BUREAU OF STANDARDS. 77

GAS ENGINEERING.

(Standards of gas service; eflicieiicy and economy of manufacture and distribution of gas; studies of gas utilization; by-product fuel processes and related tests.)

Standards for Gas Service.

A large number of cases where standards for gas service were

involved have been handled during the past year, some of which are discussed at greater length below. Among these the woi*k for the

Indiana Public Service Commission was the most extensive. The

investigation requested by the Maryland Public Service Commission

at the Annapolis gas works was well under way at the end of the

j&scal year, althougli the final report was not expected to be available

for some time. For the North Carolina Public Service Commission

the Bureau prepared a suggested supplement to the public-utilities

law of that State giving the commission adequate authority, which

they apparently do not now have, to adopt standards for service.

A survey of gas-plant conditions in North Carolina had been con- templated, but when it was determined that the commission probably did not have authority to fix standards for service the work

was postponed. At the request of the chief engineer of the Virginia

Corporation Commission, preliminary assistance has been given

looking to the adoption of standards for service in that State. Municipal problems of more or less importance have been covered

during the year for city authorities or gas companies in the following localities : Atlanta, Macon, and Savannah, Ga. ; Jacksonville,

Miami, Tampa, and Key West, Fla.; Columbia and Anderson, S. C.

;

Durham, N. C. ; Atlantic City, N. J. ; Houston, Tex. ; Sandusky,

Ohio; and Louisville, Ky. In all but one of these cases the locality was visited and conferences with one or more interested parties were

held.

The work of the Fuel Administration on standards for gas service,

esj)ecially committee activity looking to the adoption as a war measure of a low national standard for heating value, received considerable attention, and an extensive report on this matter was pre- sented to the Fuel Administration for their consideration.

During the year the third edition of Circular No. 32, " Standards

for Gas Service," was by necessity continued in use, but preparation

of a fourth edition has been undertaken. This will be completed in

the early part of the fiscal year now opening.

Indiana Gas-Standards Investigation.

During the latter part of 1918 the Public Service Commission of

Indiana received many complaints regarding the quality of the gas

service which was being rendered in a number of cities. Investigation showed that in many cases the poorer quality of gas-making

materials available under the existing war-time conditions was

responsible for deficiencies in service. A proposed new set of rules

for gas service in the State was presented at a public hearing held by

the commission in October, 1918, but there appeared to be little information available as to what heating value of gas could be eco- nomically produced by the various companies under the existing conditions. The State commission therefore appointed a committee, on

which the cities, the gas companies, and the Bureau of Standards,
78 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

as well as the commission itself, were represented, to recommend to the commission the proper heating-value standard for adoption in

the State. Data and plant records of the various gas companies were col- lected and carefully examined by this committee. Three very comprehensive tests were run at coal-gas plants in the State, and about

I'i other plants were visited in order to determine what heating

value of gas they might reasonably be expected to produce. A re- port containing the recommendations of the committee was finally

prepared and unanimously accepted by the committee, and has been

presented to the State commission.

In this work the Bureau of Standards has taken an active part.

One or more members of its stalf were constantly on hand during

the progress of the field work, and its senior representative assumed

charge of this work at the request of the chairman of the committee.

In the report which has been handed to the commission there are embodied several novel features of gas-standards requirements

which, it is believed, will lead to a better and more uniform service

to the customers of the various companies. In fact, the Bureau of

Standards believes that this investigation which has just closed is the most thorough and convincing effort that has been made in

connection with the selection by a public-service commission of a

heating-value requirement for a 'State. Furthermore, the engineering data which have been collected should be of considerable value

to the gas industry in the future. The information gained here

will be useful in many other cases. Investigation of Gas Plant at Annapolis, Md.

During the last jenv or two the local gas company at Annapolis,.

Md., not only has been unable to operate at a profit, but has not

received sufficient income to meet operating expenses. A substantial

increase in rates failed to give the necessary financial relief. The

Public Service Commission of Maryland, fearing that either another

increase in rates or a decrease in the standard of service might

ultimately become necessary, requested the cooperation of the

Bureau of Standards in determining whether economies or improvements in operation might not be effected which would enable the

company to operate more profitably.

A survey of conditions in Annapolis was made and a report

submitted to the INIaryland Public Service Commission with recom- mendations as to the management of the gas company. These, if followed cut, will ultimately turn a loss into a substantial profit.

Possibilities for a considerable extension of business were disclosed,

and the Bureau will make detailed recommendations as to the

methods it would advise to be pursued in altering and enlarging

the plant and other facilities in order to i-ender adequate and satis- factory service.

Gas-Service Inspections.

At the request of the State public service commissions and municipal authorities in many parts of the country, the gas-engineering

section of the Bureau has made service inspections or rendered

assistance in regard to these subjects. This work has included

visits and field investigations in approximately 14 different locali-
KEPOKT OF DIRECTOR OF BUREAU OE STANDARDS. 79

ties in addition to a large number of other requests which were

cared for by correspondence or conference in Washington. This

work has enabled the Bureau to place at the disposal of gas companies and municipalities the experience and advice of the Bureau

staff on matters that are very frequently the cause of considerable

controversy or public agitation. This work has been especially

important during the past year and will continue to be so while

the high costs of fuel and labor and the difficultj^ in maintaining

the usual high grade of gas service preA^ail. In many cases the

work of the Bureau has shown where conditions might readily be

improved to the advantage of all parties concerned. In other cases the Bureau has merely pointed out that the gas company in question was doing all that could be expected of it under the difficult circumstances then existing.

In general the difficulties noted were the I'esult of the extensive

disorganization of the gas industry by war conditions and the shortage of fuels of high grade which are best suited to gas making.

These conditions, with which the consumer was not always familiar,

together with the general increase in gas rates made necessary by

high costs, have caused much public dissatisfaction with gas-company operations, and it is natural that outside assistance of this sort from sources clearlj^ not partisan should have been sought. The

reports of the Bureau on the conditions found will probably lead

to improvement in the relations between the gas companies and the

public, as well as, in some cases, to an actual improvement in the

quality of service or operating efficiencies of the companies.

Gas-Appliance Laboratory Investigations.

The Bureau is cooperating actively with the industrial fuel committee of the American Gas Association in investigations of gas

utilization and burner design. In particular the committee is carry- ing on a general in"\ estigation of the various types of atmospheric

burners now in use for industrial purposes.

Up to the present time most of the industrial gas burners have

been designed by purely empirical methods, and as a result many of

them are far from efficient. The proper design of air shutter, gas

orifice and burner throat to give a maximum of air-injecting power

under conditions ordinarily met with is the part of the problem

assigned to the Bureau. This work is an essential preliminary of

the investigations which have been in mind for several years, looking to an improvement in the efficiency of use of gas. The results obtained will serve as a test of the theories Avhich have been developed as to the relation between the physical constants of the burner

and the characteristics of the gas used, and should show in a clear

and simple way the principles which underlie the efficient utilization

of gas in ordinary Bunsen-type burners.

Coking of Illinois Coal.

The great importance during the war period of substituting midcontinent coal for coals from mox'e distant sources, even in by-product coke-oven work, was well recognized. At the request of the War

Industries Board, the Bureau of Standards last year made an investigation of a new coke-oven process claimed to be especially suited to

this purpose, and in connection with this investigation later con-'
80 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

ducted a test of a plant in Minnesota, using about 7,600 tons of ccal

from the Orient mine, Franl<:lin County, 111. In carrying out these

operating tests the Bureau had the cooperation of the Bureau of

Mines, and all phases of coal handling, by-product recovery, and

laboratory tests were under observation by a staff of 37 Government

engineers and chemists employe'd on the work. In addition, those in

charge had the benefit of advice and comment from a considerable

number of specialists in the field of coke-oven operation.

All coal used and all by-products obtained were carefully

weighed or measured at regular intervals, and samples of each

material were taken for analysis. The Bureau of Standards was

responsible for the general planning and supervision of the test woi'k. Its rej)resentatives made all observations of battery operation, high-temperature measurements, by-product recovery, and

chemical-laboratory work on gas and by-products. The Bureau of

Mines was responsible for the sampling of the coal, both as it was

loaded at the mine and as dumped at the plant. It supervised the

weighing, coal-handling, coke-handling, and coke-sampling operations, and made all analyses of coal and coke. Its representatives

also made general observations on the character of the coke and

ojjeration of the ovens. In order to test the behavior of the furnace-size coke produced

from the Orient coal, arrangements were made to use about 1,800 tons of this material in the blast-furnace plant of the Mississippi

Valley Iron Co. Several experts were present during this test, and

it Avas the unanimous opinion of these persons and of the blast- furnace operators that the Illinois coke had shown highly satisfactory

results. However, it should be borne in mind that the furnace used

for this test was of small capacity, and it is not certain, therefore,

that the results in this case would be duplicated in a large-sized

furnace.

As a result of the test, it is clearly demonstrated that coke which

can be successfully used in a blast furnace can be produced from

some of the Illinois coals in the " chamber-type " oven without

radical change in the operating methods. However, it appears that

the temperature at Avhich Illinois coals should be handled for the

production of the best coke is somewhat lower than the best operating temperatures for eastern coals, and, moreover, the speed of

coking of the Illinois coals is somewhat less. The yield of gas and

by-products from Illinois coal of the kind tested is excellent both in

quantity and quality. It should be noted, however, that the coal

tested in this case represents one of the best Illinois coals for coking

purposes, being lower in ash and sulphur and otherwise superior to many from this field. Experimental-Retort Tests of Orient Coal.

In connection with other coke-oven investigations it was thought

desirable to carry out a short series of experimental-retort tests of

Illinois coals to determine the influence of temperature of coking

upon the characteristics of the coke and the quantity and quality

of gas produced. This work was done at the Sparrows Point plant

of the Bethlehem Steel Co., where apparatus was placed at the dis- posal of the Bureau through the courtesy of the engineers in charge.
KEPOKT OF DIRECTOR OF BUREAU OF STANDARDS. 81

The g-as produced at high temperatures was much greater in

volume but lower in heating value than that produced at the lower

temperatures, not only because of more complete elimination of

volatile matter from the coal, but also as a result of the greater

decomposition of the heavier volatile matter into gaseous constitu- ents at the higher temperature. At the lower temperatures the coke was very inferior to that produced at the higher temperatures, but

in no case was the temperature maintained as high ,as is generally

done in coke-oven practice.

Detailed results for the series of five tests are reported in Technologic Paper No. 134. This paper also includes data given to the

Bureau by the steel company covering tests made with the same

apparatus during the preceding two years. Proposed National Gas- Safety Code.

The Gas- Safety Code has been advanced very little during this year, but a paper on " Tests of flexible gas tubing " has been pre- pared and will soon be issued as Technologic Paper No. 133. Unfortunately, there is no prospect of much further progress on the

code until additional means are available for the Bureau's gas- engineering work. The Bureau of Standards in carrying out this in- vestigation desires to serve as a national coordinating agency to the

end that the resulting code may be adequate for the protection of

users of gas, and at the same time acceptable to the casualty and

fire-insurance interests, the gas companies and their employees, and

the gas-appliance manufacturing and selling interests. .It is well known that avoidable accidents due to ignorance, carelessness, or faulty installation result in the loss each year of hundreds

of lives and the destruction of property of large aggregate value. It may reasonably be expected that if the code could be completed and

adopted throughout the country, these losses would be considerably

reduced, both because of the official enforcement of the code and

because of its educational value to gas fitters, appliance manufacturers, utility operators, and the general public. The code would also serve to unify practice in gas installations and gas-company operation throughout the country, and such uniformity of practice would

not only tend to greater safety, but would also contribute to higher

efficiency and to more harmonious cooperation between insurance

and gas-company officials. ELECTRIC SERVICE STANDARDS.

(Standards of electric service; efficiency and economy of operation of power plants in the generation and distril)ution of electricity ; street-lighting systems ; central steam and

hot-water heating problems.)

Standards for Electric Service.

For several years the Bureau has been studying the questions of

specifications for electric light and power service and the requirements that should be made by municipalities or by State publicservice commissions of the public-utility corporations engaged in furnishing such service. This study was published in 1916 as Circular No. 56, " Standards for Electric Service."

142289—19 6
82 REPORT or DIRECTOR OE BUREAU OF STANDARDS.

In addition to proposed State rules and specifications for accept- ance of types of meters, the circular contains three regulatory ordinarices suggested for cities of various sizes, descriptions of commissions' standardizing laboratories, and a complete and exhaustive

digest of State rules and of ordinances in force in various cities. The demand for this circular has been large, and it is gratifying to note that the rules, specifications, and ordinances proposed have been

made the basis for State rules and city ordinances in many instances.

Even before the circular was published a few States had revised

their electric-service rules, and an appendix was added to include the new material. Since its publication several new commissions have

been established, the functions of old commissions changed, and service rules have been revised in a number of States. The new laws and

revised rules have been collected and are ready for inclusion in a new

edition of the circular, which will be completed during the latter part of the next fiscal year. In all this work the Bureau has profited by the cordial cooperation

of public-service commissions, municipalities, and public-service cor- porations, the National Electric Light Association, and the Association of Edison Illuminating Companies.

Standards for Street-Lighting Service.

For a year or more the Bureau was engaged in a study of street lighting in its technical and engineering aspects, with particular

reference to the requirements that should be put into contracts between municipalities and public-service corporations for furnishing

gas and electric street lighting. A number of municipal and private

plants were inspected, photometric measurements made, and confer- ences held with managers and illuminating engineei'S. The Bureau was receiving the hearty cooperation of municipalities and lighting

companies in this Avork when the war necessitated a discontinuance

of much of it on the part of the Bureau, and public-utility companies

also found themselves unable to cooperate as fully as they would

like to do. The manuscript of a circular on " Standards for Street-Lighting

Service " is partly completed. The scope and completeness of this

study of street lighting are indicated by the following proposed

table of contents: The purpose and problem of street lighting; the

measurement and distribution of light and illumination in street

l.'ghting; lamps and accessories used in street lighting; general principles governing the design of a street-lighting sj^stem ; description

of typical street-lighting systems; discussion of contracts for street- lighting service; suggested street-lighting contracts; statistical ap- pendixes. No very active work has been done on the circular during

the past fiscal year, but the digest of the literature has been kept up, new contracts obtained and analyzed, and additional data accu- mulated.

As in the case of standards for electric service, the Bureau seeks,

Avhile representing the public interest, to get the utilities' point of

view as well, and the study of street lighting will not be published

until full discussion and cooperation can be had from public-utility

corporations, technical societies, municipalities, and other interested

part'es. As in other cases, the information gained will be of great

service to the people.

i
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 83

Standards for Heating Service.

At the request of the Public Service Commission of Indiana a study of standards for central station hot-water heating service was

begun early in 1918. Field investigations of plants in Ohio. Indiana, and Illinois were made, and conferences were held with their

engineers. A proposed set of rules for hot-water heating service was formulated by the Bureau, and after public hearing on the

matter these rules were adopted by the Indiana commission substantially as recommended. The manuscript of a circular on steam and

hot-water heat'ng service is nearly completed and will be submitted

for comment and criticism to the special committee appointed by the

National District Heating Association to cooperate with the Bureau,

and to other associations and public bodies interested in centralstation heating problems. This circular covers the factors affecting

adequacy and safety of central-station heating service, the custom.er's heating requirements, and the various relations with the customer in

furnishing such service. It also contains a summary of existing

State regulations and of company rules, as well as a set of suggested

rules and contracts. TELEPHONE SERVICE.

_ (Systems of telephony ; standards of telephone service.) Telephone-Service Sta ndards.

The investigation of telephone-service standards is of great importance not only to public-utility commissions but to the telephoneusing public at large. Nearly every branch of telephone engineering

is involved in such an investigation. Standards of transmission,

traffic conditions, and the methods of handling traffic, the equipment

used in the various systems, including subscribers' instruments,

apparatus used in central office, and private branch exchanges, and

the wire plant necessaiy for subscribers' lines and trunks gll have a very direct bearing on the quality and the cost of service rendered

the public. The work of the Bureau has been directed along lines

which it is believed will best serve all interests concerned. It is seeking to gain, through field and office studies, experimental and

theoretical research, and testing, a thorough knowledge of the whole

intricate subject of telephony, and through publications, correspondence, and conferences to make its knowledge available impartially

to the telephone manufacturing and operating industries, the regulatory commissions, and the telephone-using public.

Detailed studies of the circuits and mechanism of the various auto- matic or semiautomatic types have been made, and descriptions have

been prepared covering the general functions of each switch, the

function of each switch element, and the sequence of operation of

the elements from the moment the switch is seized in the process of

making a call to the time it is released. These studies, together with

similar ones of present-day manual systems, supplemented in so far

as possible by service observations, will be of value in determining

to what extent the different grades of telephone service required

under different conditions can be adequately de!^cribed through

standard specifications. Such specifications would be invaluable to public-service commissions in the regulation of telephone utilities with equal justice to the utility and the public it serves.
84 EEPOET OF DIEECTOE OF BTJEEATJ OF STANDAEDS.

In order to put into concrete and useful form the information

available, the Bureau has in preparation two telephone circulars.

The first is intended to give a relatively brief, general description

of modern telephone systems and service, and is expected to be published within a few months. The second will describe in considerable

detail equipment and service of the type used in cities which have a number of exchanges. In the preparation of this circular the Bureau

expects to have the advantage of the continued cooperation of all the

telephone interests as well as regulatory commissions, and, as the

contents will be submitted to all concerned for criticism and discussion before publication, the circular will not be ready for publication

for a considerable time.

Testing of Telephone Circuits and Apparatus.

While the equipment of the telephone laboratory is still far from

complete, apparatus is now available for making all reasonable tests for volume and intelligibility of transmission of telephone trans- mitters, receivers, repeating cofls, and of complete talking circuits. The Bureau is also prepared to test transmitters and receivers for

their efficiency, as compared with that of standard instruments.

Standardization of Telephone Terms.

During the past half year the standards committee of the American

Institute of Electrical Engineers, through its subcommittee on te- lephony, telegraphy, and radio, representing the various telephone

interests and the Bureau of Standards, working in cooperation with

the corresponding committee of the British Institution of Electrical

Engineers, has been actively engaged in standardizing the definition

of technical terms employed in telephony. This work was at first limited to the standardization of terms introduced through the advent

of machine switching or automatic telephony, but the scope was early

extended to include the whole field of telephony.

To d{]^e many definitions have been tentatively agreed upon and

have been submitted to the British authorities for their consideration.

The large number of terms yet to be defined will receive the active

attention of the subcommittee and those cooperating with it when

meetings are resumed in the fall. ELECTROLYSIS PREVENTION.

(Study of tbe effects of stray electric currents and development and application of methods of reducing damage resulting from them.)

Electrolysis Problem Among Public Utilities. The majority of the street railways of the country are operated on

the single overhead-trolley plan, with the electric current flowing

into the rails through the car wheels after it has passed through the car motors. The current then flows back to the generating station or

substation by way of the tracks and earth, some of it, however often

flowing through underground gas and water pipes and the lead sheaths

of underground telephone and electric-light cables and sometimes

through reinforced-concrete structures. The earth conducts elec- tricity by virtue of its moisture and the salts dissolved in it, which

render it an electrolyte. Hence when the electric current flows away

from iron pipes or lead cable sheaths it carries away iron or lead by
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 85

electrolytic action, and this in time may seriously corrode the pipes

and shorten their useful life, sometimes completely destroying them

in a relatively short time. The property damage caused by these earth

currents when they are considerable affects to a greater or less degree

all the public utilities. The trouble is the more serious in places where the soil has a greater

conductivity than usual and where the conductance of the tracks is small in proportion to the current, and the distance the current travels

back to the stations is relatively great. Many remedies have been

proposed and tried, but no standard practice for the handling of the

return current has ever been agreed upon in this country. As the

electric railways have been extended and traffic has become heavier

the volume of current handled has increased very greatly, and the

resulting destructive effects, which are cumulative with time, have

become increasingly evident. In some cases litigation has resulted

between the pipe-owning companies suffering damage and the rail- way companies whose current causes the trouble. But, although the

courts have considered the question of legal responsibility, these cases did very little to prevent the trouble in an effective and economical manner. Economic Importance of the Electrolysis Problem.

The subject of electrolysis of underground pipes, cables, and other

metal structures is one which has been given more attention in recent years than formerly, but it still does not receive the attention in

many quarters that its importance deserves. When one considers

the enormous value of the pipe and cable properties buried in the

streets of cities and forming in many cases transmission networks

between cities throughout the country, and considers further that

there are very few water, gas, or lead-cable sj^stems which are not more or less subject at some points to electi'olytic damage from stray

currents, it is possible to form a better judgment of the practical

importance of this subject. The water and gas pipe systems of this

country alone have an aggregate value at the present time in excess of a billion of dollai^s, and in addition to this there is a vast extent

of underground lead-cable systems belonging to telephone and electric

power companies and to municipalities. There are also possibilities

of trouble in the case of bridge structures, portions of steel-frame

buildings, and piers, which are occasionally exposed to damage from

this source. While the total losses due to shortening the life of underground

pipes and cables must be considerable, such loss does not by any means represent the total annual damage due directly to electrolysis- It is well known that the annual loss due to leakage of water and gas-, from distribution systems is very great. It is true that only a part,,

and probably a small part, of the total leakage is due solely to. electrolysis; but it is only necessary to assume that a few per cent

of the total is due to the more rapid development of leaks caused

by electrolysis in order to make the total loss resulting from this cause run well into the millions annually.

Inconvenience and Hazard Due to Electrolysis.

It is not alone the property loss, however, that makes the electrolysis problem one of importance. An important fact is the in-
86 REPORT OF DIKECTOE OF BUREAU OF STANDARDS.

convenience to consumers of water, gas, and telephone service due to the interi-uption of the service when repairs are made necessary by

electrolytic damage. Possible interruption of the service of police

and fire-alarm systems is also one of considerable importance to almost every municipality.

Wherever currents are permitted to flow on the underground-pipe

systems there is the jDOSSibility of electric arcs being formed when

pipes are disconnected or when different pipe systems make momentary contact. Accidents of this kind are rare, but they have sometimes occurred, resulting in the less of life and a considerable

damage to property. Cases have occurred also in which leakage of

gas resulting from electrolytic corrosion of the pipe has given rise to explosion with disastrous results. Many gas explosions in basements and manholes have occurred, and, although it is difficult to determine what proportion is due to electrolysis, undoubtedly some

of then"! are due to this cause. A water-pipe line weakened by electroyltic corrosion may even

present a fire hazard much greater than would result from interruption of water supply at normal times. In many cities it is quite

common practice durnig bad fires to increase temporarily the water

pressure in tlie district adjacent to the fire. It is very obvious that a badly corroded water main might be capable of withstanding tlie normal pressure on the system, and thus give no warning of the

weakenecl condition of the pipe, but at the critical juncture during a bad fire when the pressure is suddenly increased the pipe may burst

and thus seriously hamper the work of fire fighting. It will readily

be appreciated that in any region in which electrolysis damage is in

pi'Ogress to a greater or less extent the mains are far more likely to break at these critical times than at any other period, and thus a real,

though indirect, fire and life hazard due to electrolysis must be

recognized.

Current Work on Electrolysis Mitigation and Related Problems,

In the field of electrolysis mitigation the Bureau's work was greatly

curtailed during the war, since practically all the men formerly

engaged in it were diverted to military problems. Since the close of

hostilities more active work has again been undertaken, and most of

the investigations mentioned below have been carried out during the

last few months of the year. Electrolysis Surveys.

In Mihvaukee the question of damage by electrolysis has been in

dispute for some time, the city having brought suit against the street railway company to restrain it from further damaging the water

mains. Since a controversy in the courts did not promise a satis- factory settlement of this difficult technical problem, the Wisconsin

Eailroad Commission was asked to exercise its authority in prescribing the responsibility to be assumed by the various utilities in dealing

with the problem. The commission, recognizing that the first thing

necessary was a more complete knowledge of the facts in the case, requested the Bureau to supervise a survey to be made under the

authority of the commission. This survey was m.ade in the fall of

1918 and a report of the findings was submitted to the railroad commission in November.
KEPOKT OF DERECTOR OF BUREAU OF STANDARDS. 87

In Wilmington, Del., the Bureau some years ago suggested that the

street railway company use a three-wire power-distribution system

to avoid electrolysis troubles. Such a system was designed and in- stalled by the company and proved to be thoroughly satisfactory

until very recently, when the rapid growth of the city, with conse- quent heavy increase in the traffic in certain sections, unbalanced the

load on the system, so that there appeared to be a possibility of damage, particularly to important telephone cables which pass through

Wilmington. Late in 1918 one of the Bureau's engineers made a

detailed stud}' of the situation and assisted in the design and installation of supplementary protection to the cables which it is believed

will remedv the undesirable conditions which had developed.

During the last sjDring two ele.trolj'sis surveys wei'e made, one

in Marion, Ohio, and the other in Brazil, Ind. The Marion survey, was made at the joint request of the utilities and the municipality,

and the Brazil survey was made at the request of the Indiana State

Public Utilities Commission. Reports have been submitted on both

of these surveys which are in the nature of preliminary reports,

and as soon as the recommendations embodied in these reports have

been complied with it is expected that the Bureau will make some

additional tests to determine whether additional remedial measures

are called for. Investigation of Corrosion of Cables in St. Louis.

Shortly before the outbreak of the war, the Union Electric Light

& Power Co., of St. Louis, brought to the attention of the Bureau a

peculiar case of corrosion of its lead cable sheaths, Avhich appeared,

superficially at least, to be very different from that commonly met

with in electrolytic corrosion. A few preliminary tests were made

in connection with this by the Bureau just prior to the outbreak of

the war, but these were dropped when it bacame necessary to devote

all of the energies of the section to the development of war apparatus.

Eecentljr the Bureau again communicated with the Union Electric

Light & Power Co. and found that they had not as yet reached any

solution of the difficult}^ and were very anxious to have the Bureau

resume the investigation. This Avas done, and a considerable amount

of worlv has been carried on both in St. Louis and in the laboratories

of the Bureau during the past six months. While the investigation

is not completed and it is not yet possible to state with certainty tlie exact cause or causes of the trouble, practically all the evidence thus

far obtained tends to show that the trouble is a combination of several causes, chief of which is the fact that during the first few months

after the installation of these cable systems they were subjected to very high positive potentials, probably of sufficient magnitude to cause most of the corrosion that is now being observed. Subsequent

failures gradually developed, due partly to the elevated temperature

at which the cables were operated, which was augmented by a peculiar type of conduit used. The Bureau is at present engaged in in- vestigating a few special questions that have come up. but it is not

anticipated that these investigations will change the general conclusion reached.

Improved Methods for Making Electrolysis Surveys.

With the extension of the work on mitigation of electrolysis it has

become more and more evident that the older methods of making elec-
88 REPORT OP DIRECTOR OF BUREAU OF STANDARDS.

trolysis surveys are decidedly unsatisfactory and sometimes may be

misleading. Consequently, attention has recently been given to the

development of improved methods of making such surveys. Particular attention has been given to developing methods of measuring the current flowing in pipes aiad the leakage of current from pipes, in- stead of following the old procedure of measuring the differences in

voltage between the diJfferent metal structures concerned in electrolysis. The development of these new methods of measurement has re- quired considerable investigation to determine the practicability of

applying various principles in the measuring instruments. While

none of these investigations are complete, a number of instruments

have been built and have given satisfactory results in laboratory tests. Plans are under way to try out these instruments in measurements

under field conditions during the next few months.

Experimental Work on Electrolytic Corrosion of Lead,

One of the serious types of damage resulting from the flow of

stray electric currents is the destruction of the lead sheaths of cables,

which results in deterioration of the cable insulation, and conse- quently in short circuits and destruction of the cables. Because of

the contradictory character of available evidence as to the conditions

tinder which such corrosion of lead occurs, it has appeared necessary

to do a great deal of laborator}' work to determine these conditions;

for example, tests have been made to determine the variation of cor- rosion with varjdng current densities in earth, sand, and water. In

accordance with previous results, it has been found that the corrosion

per unit of current is greater when the actual current density is small

than when the currents flowing are large. Another condition which

affects the rate of corrosion is the percentage of moisture present

in the earth or sand. In general, corrosion takes place more rapidly

when there is more water present.

In many places, as the demands for power vary, certain parts of

the pipe systems are alternately positive and negative, so that at times the current flows from, and at other times it flows into, the

metal. There have been marked differences of opinion as to the

electrolytic effects obtained under such conditions, and a long series

of experiments have been carried on to determine what the effects are. In these experiments specimens of lead have been made alter- nately positive and negatiA'e for different fractions of the time. The

relative amount of corrosion has been found to decrease very rapidly

when the portion of tim.e during which the specimens are positive is decreased. It appears probable tliat in such cases some of the metal

is actually redeposited on the specimen when the current is reversed.

This, however, has not yet been definitely proved.

SAFETY ENGINEERING AND SAFETY STANDARDS.

(StiKly of mpnns of retliicinf: li.izard to life nnd property arising from the use of elec- tricity and from otlier industrial processes ; development nnd application of safety codes

for the prevention of accidents, notably the National Electrical Safety Code.) National Electrical Safety Code.

The Bureau has been engaged for six years in a study of the life hazard in electrical practice and in the preparation and application

of the National Electrical Safety Code. In this work it has had the

cooperation and assistance of a large number of engineers, many of
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 89

whom are connected with the electrical operating and manufacturing

companies, others being engineers and inspectors of State commissions, municipalities, and insurance underwriters. The various national associations connected with the electrical industry have also

cooperated effectively in this work. The importance of having a national code uniform in all the States is realized to be quite as great

for accident-prevention rules as for fire-prevention rules, and the

advantage of having such a code prepared and presented by a national agency that can study the subject thoroughly and consult all the interests affected is obvious.

The safety code consists of four principal parts, as follows:

1. Rules for the installation and maintenance of machinery,

switchboards, and wire in central stations and substations.

2. Eules for the construction and maintenance of overhead and

underground lines for the transmission and distribution of electrical

energy and intelligence.

3. Eules for the installation and maintenance of electrical apparatus and wiring in factories, residences, and wherever electricity

is utilized for light, heat, or power.

4. Eules to be observed by operators in working on or near elec- trical machines or lines. This code does not include the matter covered by the Underwriters' Electrical Code, but it is parallel to the latter and consistent

with it. The code is intended to be adopted by State industrial and publicservice commissions and municipalities and to be complied with by

public-service and industrial corporations. It is also intended to be

adopted voluntarily by electrical interests when the code has not

been adopted by any administrative body having jurisdiction in their

district. The Bureau's thorough study of the diverse conditions under which

electricity is generated, distributed, and utilized, and of the effect of the rules on operating and construction costs, has secured a code

which involves no unreasonable expense, but in general assures an

adequate measure of safety and a useful standardization of practice.

The large number of conferences held in all parts of the country for

discussion of preliminary drafts of the code aided largely in its development to the point where it was possible to recommend it for

general use throughout the country. The varying conditions in dif- ferent geographical sections and in thickly and thinly populated

districts have been given careful attention.

The code was published originally in two installments for examination and criticism; the operating rules were published in August,

1914, and revised in May, 1915 ; the construction rules were published

in April, 1915. Both operating and construction rules, again revised

after a general conference of all interests in Chicago in the spring of

1916, were combiiied in a single volume, circular No. 54, which was

published in November, 191 G, with a recommendation for actual field

trial. It has been the intent of the Bureau, as well as the desire of all branches of the industry, that the rules should be revised and ex- tended as experience in their use and the progress of the electrical
90 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

industry shows revision and amplification to be to the public advantage. The present edition of Circular No. 64 has been exhausted,

and a revision is now under way which will be completed be- fore reprinting the circular. In this revision only minor changes

in subject matter have been made, but there will be considerable

changes in form, with a view to making the code more concise and more convenient for refei-ence. For this purpose the rules will be

separated and published in one volume supplemented by separate

volumes, one giving explanations of the rules and examples of their

application and another engineering data which have been worked

out in connection with the development of the code.

Engineering and Experimental Work in Connection with the Safety

Code.

Considerable work has been done on engineering data for the construction of outdoor electrical lines, especially with reference to poles

and steel towers for supporting overhead conductors and to the sags

of the conductors so supported. Sags have been computed for temperatui'es other than those used in the original published tables, and

steel wires and cables have also been considered. An article by members of the staff on the latter subject was published in the Electrical

World.

Experiments for determining the pressure of the wind upon over- head wires and the shielding effect of wires upon each other where

they are closely grouped have been carried out. Models were set up in the wind tunnel and currents of air of different measured

velocities were caused to impinge upon them. Measurements of the

pressure under such conditions showed that there is a definite shielding efi'ect when two or more wires lie in the same plane which is nearly parallel to the direction of the wind. Experiments in the

open air which have been planned by the Western Union Telegraph

Co. will be carried out with the cooperation of this Bui-eau.

National Electrical Safety Code in Practical Use.

The code has now been adopted in one form or another, in part

or in whole, by some 20 administrative bodies, and many others have

taken favorable action upon it, such as the issuance of bulletins rec- ommending the application of the code. In a few States its application has been made mandatory, notably in Pennsylvania, Wisconsin, and Montana. The code is also being used by the inspection

departments of many cities and boards of underwriters. It is being

used as a basis for a merit-rating schedule by casualty interests just

as the Underwriters' Electrical Code has been used by the fire underwriters for some years. Such schedule ratings should result in

emphasizing both the merits and demerits of particular installations

from the safety standpoint and tend to reduce accidents by proper

financial recognition of each improvement made.

The code is also being voluntarily applied by a large number of

utilities and industrial concerns in their own practice. It is receiving the general approval of all these interests as its usefulness is becoming recognized and its advantages are seen to be greater than

any minor present inconvenience which its introduction may cause.

It is becoming generally understood that the stability in electrical

practice provided by such a national standard conduces greatly to
KEPOKT OF DIRECTOB OF BUREAU OF STANDARDS. 91

the general economy, the necessity for which has been emphasized

during this period of national stress. Industrial Safety Standards.

As a result of the work on the National Electrical Safety Code

and the numerous points of contact thus established with State

authorities and others interested in safety work the Bureau has been

called upon to enlarge the scope of this work and to consider safety

requirements in other than the electrical industry.

In 1917 the United States Employees' Compensation Commission

undertook a general inspection of the arsenals and navy yards of this

country from the safety standpoint. The National Electrical Safety

Code was utilized as a standard of reference in this work. In order

to improve the conditions found safety engineers were appointed by

the War and Navy Departments in each one of the navy yards and

arsenals, and the engineers so appointed held several conferences for

the purpose of formulating definite safety standards for application

in the Federal establishments. Representatives of the Bureau were

invited to attend these conferences, and the Bureau was later asked

to undertake the revision and codification of the tentative rules

which were drawn up to prevent accidents. A set of standards, in- cluding the National Electrical Safety Code, was adopted by the

safety engineers as a result of this work, and these standards have

been applied by the War and Navy Departments.

The need for carrying out work of this kind in a more comprehensive way and with results which should be more generally applicable soon became evident, and the Bureau, consequently, has undertaken a study of other safety rules and has begun the formulation of

a series of national industrial safety codes. These will accomplish

for other industries what the National Electrical Safety Code has

done for the electrical industries. They will be available for the use of State commissions, mimicipal inspection departments, casualty

insurance companies, and others concerned with the application of

such rules. The work will be carried out v/ith the cooperation of

State and municipal authorities, manufacturers, insurance organizations, technical societies, and other bodies concerned with such

matters. In order to arrange for more complete cooperation in this work

and to insure the coordination of the efforts of all parties concerned,

a conference was held at the Bureau on January 15, 1919, which was

attended by more than 100 representatives of different organizations

concerned with safety standards. This conference agreed that the

Bureau of Standards was the most suitable agency to take the leadership in this work. It is expected to hold a second conference in a few

months to consider further the best means of securing cooperation

and of proceeding with the work.

In the meantime the Bureau staff has prepared tentative drafts of

rules covering the requirements to prevent accidents, as follows

:

National Elevator-Safety Code; National Code for Safeguarding

Machines and Machine Drives; National Code for the Protection of

Head and Eyes of Industrial Workers; National Code for Safeguarding Remote Control Apparatus. Other industries will be considered as rapidly as the work can be taken up, but the present staff of the section is not sufficient for making very rapid progress.
92 KEPOKT OF DIRECTOE OF BUEEAU OF STANDAEDS.

3. HEAT AND THERMOMETRY.

[Establishment of the standard scales of temperature throughout the range of measurable temperatures; testing and standardization of thermometers, pyrometers, and other temperature- measuring instruments; determination of specific and latent heats, heats of reaction, melting and freezing points, and other properties of materials in the determination of which precise heat and temperature measurements are the principal requirement; standardization of calo- rimeters; production and distribution of standard heat and terperature samples; industrial applications of heat and temperature measurements; determination of fundamental engineering data involving thermal constants; determination of the fire-resistive properties of structural materials; investigations relating to automotive power plants, fuels, and lubricants.] Thermometer, Pyrometer, and Heat Tests. The tests completed in the division during the year are summarized

as follows

The number of mercurial thermometers of all kinds, exclusive of

clinical theremometers, submitted for test was 4,832, of which 4,100

received certificates or reports. Among those submitted were 479

Parr calorimetric thermometers, 23 high-precision calorimetric thermometers, 121 Beckmann thermometers, 30 clincal standards, and the

remainder laboratory and special thermometers of various types, ranging from below 0° C. and up to 500° C. Ninety-nine airplane thermometers of various types were tested for the War and Navy Departments. Of the 19,773 clinical thermometers submitted, 18,503, or

94.1 per cent, were certified. In addition to the above there were

tested 11 platinum resistance theremometers and 6 special thermocouples, while freezing-point determinations were made on 75 samples

of materials.

In the high-temperature laboratories the following tests were made: Ninety-four thermocouples, 13 indicating instruments for

thermocouples, 5 homogeneity tests of thermocouples, 8 optical pyrometers, 9 pyrometer lamps, 2 absorption glasses, 70 melting points, and

7 special tests. One hundred and sixtj samples of metals with certified melting

points were distributed.

The heat-measurements laboratory distributed 204 standard combustion samples. Three gas calorimeters were tested. The heating

values of a number of samples of gasoline and fuel oil and the

thermal conductivities of a number of insulating materials were

determined.

A considerable amount of testing done by the section on auto- motive power plants, fuels, and lubricants, being of an investigative

character, is summarized under the work of that section.

The work of testing done in this division was about equally di- vided between work done for the Government and that done for

the public.

Publications.

The following papers relating to the work of the division have

been published during the year or are in press. These papers are

briefly referred to in various sections of this report

Misleading Certificates for Clinical Thermometers : Jour. Am. Med. Assoc., February S, 1019 ; .Am. Druggist and Pilar. Rec, February, 1919 ; The Military

Surgeon, vol. 44, p. 297, 1919. Tolerances for Laboratory Thermometers: Published as a preliminary cir- cular letter. Thermometers for Airnlane Engines: Fourth Ann. Kept, of the Natl. Advisory Com. for Aeronautics.
REPORT or DIRECTOR OF BUREAU OF STANDARDS. 93

A Standardized Method for the Determination of Solidification Points, Especiallv of Naphthalene and Paraflin: Bureau of Standards Scientific Paper

No. 340. The Standardization of the Sulphur Boiling Point: Jour. Am. Chem, Soc,

Tol. 41, p. 745, 1919 ; Bureau of Standards Scientific Paper No. 339. Resonance and Ionization Potentials for Electrons in Metallic Vapors: Phil. Mag., vol. 36, p. 64, 1918. Electronic Frequency and Atomic Number : Phys. Rev., vol. 12, p. 115, 1918. Low Voltage Discharge in Sodium Vapor : Jour. Wash. Acad. Sci., vol. 8, p. 513, 1918. Some Peculiar Thermoelectric Effects : Jour. Wash. Acad. Sci., vol. 8, p. 54.^ 1918. Melting Points of the Chemical Elements and Other Standard Temperatures : Bureau of Standards Circular No. 35. Ionization and Resonance Potential.^ for Electi'ons in Vapors of Magnesium

and Thallium: Phil. Mag., vol. 37, p. 33, 1918. Ionization and Resonance Potentials for Electrons in Vapors of Arsenic,

Rubidium, and Cfesium : Phys. Rev., vol. 13, p. 59, 1919. Efflux of Gas Through Small Orifices: Bureau of Standards Scientific Paper.

Fire Tests of Concrete Columns : Proc. Am. Concrete Inst., vol. 15, 1919. A Comparison of the Heat Insulating Properties of Some of the Materials

Used in Fire-Resistive Construction : Bureau of Standards Technologic Paper No. 130. Fuel Economy of Automotive Engines : Jour. Soc. Automotive Engs., voL

4, 1919. Pyrometry : Liddell's Handbook for Chemical and Metallurgical Engineers.

The following 11 papers are to appear in the Transactions of the

American Institute of Mining and Metallurgical Engineers

:

Thermoelectric Pyrometry.

Temperature Measurements in Rotary Cement Kilns. Radiation and Optical Pyrometry.

The Melting Point of Refractories. High-Temperature Control. Recording Pyrometry.

Heat Treatment of Glass. The High Temperature Scale. Metals for Pyrometer Standardization.

Characteristics of Glass in the Annealing Range.

High-Temperature Thermometers.

The following 21 papers will be published in the fourth annual

report of the National Advisory Committee for Aeronautics

:

Spark-Plug Defects and Tests. Properties and Preparation of Ceramic Insulators for Spark Plugs.

Effect of Pressure and Temperature on the Sparking Voltage. Heat Energy of Various Ignition Sparks.

Temperature in Spark Plugs Having Brass and Steel Shells. The Subsidiary Gap as a Means for Improving Ignition. Characteristics of High-Tension Magnetos.

The work described in the above seven papers relating to ignition

systems was done with the active cooperation of the electrical or ceramic division of the Bureau.

Synopsis of Aeronautic Radiator Investigations for 1917-18. General Analysis of Radiator Problems. General Discussion of Test Methods for Radiators. Head Resistance Due to Radiators.

Effects of Altitude on Radiator Performance.

Results of Tests on Radiators for Aircraft Engines.

Some Problems of Radiation.

Effect of Compression Ratio, Pressure, and Temperature on Power. A Study of Airplane Engine Tests. Power Characteristics of Fuels for Aircraft Engines.

Description of Altitude Laboratory.
94 KEPORT OF DIRECTOR OF BUREAU OF STAND4EDS.

Carbureting Conditions Characteristic of Aircraft Engines.

Metering Characteristics of Carbureters.

Effect of Water Injection on Gas-Engine Performance.

The following papers relating to fuels and lubrication are tlie vrork of the division of miscellaneous materials of the Bureau

Viscosity of Gasoline: Bureau of Standarrls Technologic Paper No. 12.5. Report on " Tag " Closed Flash-Point Tester : Proc. Am. Soc. for Testing

Mat., Vol. 19 ; 1919. Information Furnished.

Hundreds of letters and reports relating to the work of the heat

division were prepared in repl_Y to requests for information on test- ing of temperature-measuring insti^uments, methods of temperature

measurement, industrial temperature installations, melting points,

specific heats, heats of combustion and other thermal constants,

calorimetry, heat transfer and thermal conductivity, fire-resistive properties of structural materials, industrial fire hazards, fire pre- vention, safety of combustibles in storage and shipment, liquid fuels,

lubricants, automotive power plants, etc. Many engineers and technical men have visited the laboratories for consultation on special

problems. A number of devices were submitted for examination and

criticism.

Outside Relations.

The work of this division has served many National, State, and

municipal bureaus, engineering and technical societies and committees, testing and research laboratories, and many industries in which

the measurement or control of heat and temperature are of fundamental importance.

The thermometer laboratories haA-e cooperated with the Standards

Department of the State of Massachusetts in matters relating to the

testing of clinical thermometers; with manufacturers and testing

laboratories on matters relating to temperature measurement and

the testing of thermometers; with the Customs Services on the standardization of tests required in collection of import duties; with the

military services, by making investigations relating to airplane thermometers: and with the American Association of Clinical Thermometer Manufacturers.

The high-temperature laboratories have cooperated with the representatives of many industries on matters relating to the measure- ment or control of high temperatures. Papers have been presented

at meetings of the American Phvsical Society, the Optical Society

of America, and the Philosophical Society of Washington. The

section is represented on committees of the National Research Council and the Optical Society of America.

The section on heat measurements undertook at the instance of

the Bureau of Mines, certain low-temperature investigations closely

related to the recovery of helium, an extensive investigation of tor- pedo-power plants for the Bux'eau of Ordnance of the Navv, and

assisted the Bureau of Aircraft Production in a research on captive

balloons. Numerous tests of special appliances were made for the

Inventions Section of the General Staff, United States Army.

The section on thermodynamics has been represented on committees of the American Society of Mechanical Engineers and the National Eesearcli Council.
KEPOKT OF DIRECTOR OF BUREAU OF STANDARDS. 95

The low-temperature laboratories have cooperated -in special tests for various military agencies and have supplied liquid air to a number of research laboratories.

Members of the section on fire resistance of materials and fire pre- vention have participated in committee activities of the National

Fire-Protection Association, the American Concrete Institute, and

the American Society for Testing Materials. The section was also

represented on a committee of the War Department engaged in the

standardization of equipment. The investigations on the fire-resis- tive properties of structural-steel building columns are being con- ducted in cooperation with the Associated Factory Mutual Fire In- surance Cos., and the National Board of Fire Underwriters.

A large part of the work of the section of automotive power plants

has been clone under the direction of the National Advisory Committee for Aeronautics and in close cooperation with the following

agencies: The Bureau of Aircraft Production, the Division of Military Aeronautics, the Motor Transport Corps, the Inventions Section

of the General Staff, the General Engineer Depot, the Engineering

Division of McCook Field, the Bureau of Steam Engineering, the

Bureau of Mines, the Fuel Administration, and the Society of Automotive Engineers. The section Avas represented on the Interallied

Commission on Specifications for Petroleum Products, and on the

Committee for Standardization of Petroleum Specifications.

The Bureau is greatly indebted to many manufacturers of auto- motive power plants, airplanes, and accessories for supplying materials and test specimens required in the investigations carried out

in these laboratories. Pai'ticular acknowledgment is due in these

respects to the Atlantic Refining Co., the Wright-Martin Aircraft

Corp., the manufacturers of spark plugs, magnetos, carbureters, and

radiators, and the refiners of lubricating oils. THERMOMETRY.

(Researches on the standard scale of temperature and thermometric fixed points from

the lowest attainable temperatures up to about 500° C. ; maintenance of working stand- ards within the above range ; methods of standardizing temperature-measuring instru- ments, such as liquid in glass thermometers, vapor-pressure thermometers, resistance thermometers, thermocouples : the testing and certification of temperature-measuring in- fctrumeuts ; methods of measuring temperatures.)

Clinical Thermometers.

The matter of misleading certificates for clinical thermometers,

referred to in the last annual report, has continued to demand attention. Many manufacturers and dealers have issued certificates which

were so worded as to lead the purchaser to believe that the thermometer accompanying the certificate had been certified by the Bureau of

Standards. An official letter calling attention to this practice,

accompanied by illustrations showing types of these misleading certificates, was published in several of the leading medical and drug

journals of the country.

The Bureau has assisted the Department of Standards of the State

of Massachusetts in the preparation of testing regulations relative

to the enforcement of recent legislation by that State in reference to the sale of clinical thermometers.

Tolerances for Laboratory Thermometers.

In the certification of laboratory thermometers, as in the case of

many other measuring instruments, it has been necessary to define
96 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

certain limits within which the indications of the instruments must

be correct. Thermometers found correct within the required limits

receive certificates showing the corrections found at the several test points. If the thermometers are not correct within the tolerances, or are otherwise defective, they are refused certification, although,

for the convenience of the owner, a report may be issued giving the

corrections resulting from the test and stating the reasons why the

thermometer was refused certification. A Bureau certificate thus, in

addition to the information furnished in the table of corre:tions, is an indication that the thermometer is of satisfactory quality. A

statement of the proposed tolerances applicable to different types of

thermometers was issued during the year to manufacturers and others

interested in the subject. The tolerances, based on long experience

in testing thermometers, were tentatively adopted July 1, 1919, with a view to their subsequent revision, if necessary. The tolerances and

other requirements finally adopted will be included in the next

revision of Circular No. 8, on the Testing of Thermometers.

Airplane Thermometers.

The work in connection with the development of thermometers for

airplane engines was continued this year. In addition to routine tests of instruments submitted by the Army

and Navy, special tests were made from time to time, including

vibration tests, tests to determine the variance between readings

taken on rising and falling temperatures, tests for lag of reading, etc. A class of instruction on the construction and use of aviation in- struments was conducted for naval aviators by the Bureau at the

request of the Navy Department. A lecture on airplane thermometers was given by a member of the section before this class. These

officers also visited the laboratory and were shown the methods employed in testing airplane thermometers.

A circular on airplane thermometers was prepared and distributed

to departments of the Government, manufacturers, and other interested parties. This circular was revised and has been submitted to the National Advisory Committee for Aeronautics for publication in

their report.

Standardization of the Sulphur Boiling Point.

The necessary precautions to be observed in the use of the sulphur

boiling point as a fixed point of the thermometric scale are described

in a paper published under the above title. Standardized Solidification Test. The work of standardizing a method for the determination of the

solidification point of naphthalene, undertaken in cooperation witn

the laboratories of the Customs Service, was brought to a close during the year. The results of the comparative tests based on this

method were received and assembled. The excellent agreement obtained by the various laboratories among themselves and with the

Bureau indicated the method as adopted to be very satisfactory.

The method has been applied to the determination of the freezing

points of other substances. A Bureau publication describing the

method and summarizing the results of the work is now in press.
KEPORT OF DIRECTOR OF BUREAU OF STANDARDS. 97

Thermometer Comparator.

During the year a new electrically heated thermometer comparator,

employing stirred, molten metal to secure uniformity of temperature, was designed, constructed, and put into use. The thermometers are

inserted into thin closed-end steel tubes dipping into the molten

metal. The temperature distribution is uniform to within about

0.1° C. over a length of about 35 centimeters, from a point about 10

centimeters below the top of the bath. This comparator has proven

very satisfactory for the testing of thermometers in the interval 300

to 550° C, and it is believed that similar comparators will find considerable application in the pointing and testing of thermometers by

mamifacturers.

HIGH TEMPERATURES.

(Researches on the standard scale of temperature and thermometrlc fixed points in the

interval from 500° C. up to the highest attainable temperatures ; maintenance of working

standards in the above range ; standardization and distribution of standard samples for thermometric fixed points [for example, a series of pure metals of certified melting

points] ; methods of standardization and the testing and certification of pyrometers, such

as thermocouples, resistance pyrometers, pyrometer galvanometers, optical pyrometers

[including absorption glasses and color screens], radiation pyrometers, etc. ; physical

properties of materials at high temperatures, such as emissivity [monochromatic and

total], specific heats, melting points [of refractories, metals, fire brick, etc.] ; ionization and radiation in gases and vapors, etc. ; Industrial pyrometry and the measurement of the temperatures in industrial processes ; the annealing of glass.) Investigations in Electronics.

Two general types of inelastic impact between an electron and an atom may occur. The first of these results in an orbital shift of the

electrons bound in the atom, and the second in the complete removal

of an electron or ionization of the atom. The respective potential

differences through which an electron must fall to acquire sufficient velocity for these two types of collision to occur are known as the resonance and ionization potentials for the particular metal in question. The determination of these constants has been continued. Work

of this character is of theoretical interest from the standpoint of pure

physics, and of practical interest in that it furnishes further evidence

toward an explanation of the phenomena of ionization and related

problems which arise in the design of vacuum tubes for wireless

telephony and telegraphy, rectifiers, etc. Five papers have been published this year on the above and related

subjects, two appearing in the London Philosophical Magazine, two

in the Physical Eeview, and one in the Journal of the Washington

Academy of Sciences. One additional paper is in preparation. The

constants for 12 different metals have been determined. The resvilts have been correlated with existing spectroscopic data and have also been used for a determination of the universal constant of action

giving /(=6.55xl0"^' erg seconds. Spectroscopic series in lead and

arsenic have been predicted on the basis of the data for these elements.

Melting Points of Chemical Elements and Other Standard Temperatures. A revison of Circular No. 35 makes the data on standard fixed temperatures fairly complete. The edition has been exhausted, and a new

edition is in preparation in which a more complete discussion of the

high-temperature scale adopted by this Bureau will be presented.

142289—19-^7
98 EEPOET OP DIRECTOK OF BUEEAU 01" STANDAEDS.

General Pyrometry.

A treatise on the general methods of pyrometry applicable to the

chemical and metallurgical industries is in process of preparation.

Thermoelectric Pyrometry.

Thermoelectric pyrometry is the most important subject, industrially, in the field of liigli-temperature measurement and control.

An extensive paper on this subject has been prepared as one of the

Bureau's scientific publications, in which are treated the fundamental methods employed, necessary precautions which must be observed

in the use of the various instruments, and general information of

importance in teclinical jDractice. The above paper is the most complete treatise on recent developments in industrial thermoelectric

pyrometry.

Radiation and Optical Pyrometry.

Above 1,500° C. radiation and optical pyrometers afford practically

the only feasible method of temperature measurement, and for many

processes below this temperature these instrmnents have proved of

great value in the temperature control of industrial processes. A

paper, published in the Transactions of the American Institute of

Milling and Metallurgical Engineers, under the above title, describes

the various instruments and methods employed, and gives in simple

form the theories upon wliich they are based. Many specific a^Dplications are discussed, as, for example, the measurement of the temperature of glowing platinum gauze employed as a catalyzing agent. This

latter problem arose in the process of nitrogen fixation in the manufacture of explosives. Various tables of data useful in computing

temperature measurements are summarized in convenient form.

Recording Pyrometry.

One of the important features of thermoelectric and radiation

pyrometry is that printed records of the temperature of a process over an extended interval of time can be readily secured. Many

forms of instrument are now manufactured in this country which

produce such records automatically. Thus, an operator may be in- structed to heat a furnace at a definite rate, and a printed record is available to show whether or not the instructions have been followed.

In a paper under the above title, published in the Transactions of the

American Institute of Mining and Metallurgical Engineers, the

methods employed in recording pj-rometry have been considered

from the point of view of their industrial applications.

High-Temperature Control.

Not only is it desirable to obtain a printed record of the temperatures in any particular process, but it is essential to have some means

whereby a specified rate of heating or cooling may be readily fol- lowed. Various methods are employed for this purpose. In certain

large installations the temperature-measuring apparatus is centralized by use of a switchboard system similar to the ordinary telephone

SAvitcliboard. The control operators measure all the temperatures and

instruct the operators of the furnaces by means of pneumatic-tube

communication or signal system with colored lights. In certain

processes the entire control may be made automatic, even to the regulation of valves in a gas or oil-fired furnace. If the temperature of
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 99

the furnace is too high, the supply of fuel is decreased automatically.

A paper has been prepared for publication in the Transactions of the

American Institute of Mining and Metallurgical Engineers, in which

are discussed the applications of the various processes employed for

manual and automatic temperature control. Melting Point of Refractories.

A knowledge of the melting points of fire bricks, cements, etc., used

in furnace construction is necessary in order that the proper factor

of safety for the operation of any furnace may be known. A paper

under the above title discusses the methods employed for such determinations and the precautions which must be observed, in order that

reliable measurements may be obtained. When it is realized that the

failure of a large furnace in certain industrial operations may entail

losses amounting to thousands of dollars, it is readily appreciated

that a thorough study of the thermal properties of the materials en- tering into the construction of the furnace is necessary. Heat Treatment of Glass.

War conditions affecting the production of optical glass demanded

a more thorough investigation of the annealing processes. To establish effective and economical methods of operation in annealing,

it is necessary to determine the practicable annealing temperature

range and to investigate certain physical characteristics of the glass

in that range. This was done for many different optical glasses. As

a result of these investigations, certain relatively simple tests for determining the practical annealing range and annealing procedure for

any given glass have been established. An investigation of the dis- tribution of the stresses, the presence of which in the glass necessi- tates annealing, is also under way with the purpose in view of determining the practicability of establishing standards for the degree

of annealing and of studying the relative efficiency of different an- nealing procedures. Two papers relating to these subjects have been

submitted for publication, and a third is in preparation.

Temperature Measurements in Rotary Portland-Cement Kilns.

In connection with an investigation of certain phases of cement

manufacture, the Bureau was called upon to measure the temperatures in the sintering zone, rear end, and stacks of a 125 by 8 foot

dry-process, coal-fired rotary kiln. Previous to this work no accurate methods of pyrometric measurements in the sintering zone had

been described. Using a disappearing filament type of optical pyrometer, and on stopping the kiln, coal, and air supply for a few

moments at a time, a series of temperature-time curves, showing

measurements on the lining uncovered by clinker, gave the temperature of the kiln. By means of such data burning temperatures and

chemical composition of the clinker may be correlated with the object of improving the quality of the finished product. A paper on

this subject has been submitted for publication.

Coke-Oven Investigation.

The work described in the last annual report has been comipleted.

Methods of temperature measurement in the process of coking were

successfully applied to two types of ovens. The form of the temperature-time curve during coking is an important factor in the pro-
100 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

duction of high-grade coke. A full report of the experimental work

is being prepared.

The High-Temperature Scale.

The temperature scale, unlike many other standards of measurement, can not be fixed in terms of a concrete standard. Thus the

scale can not be extended by multiplication or division, as is the case, for example, with the meter, the kilogram, the ohm, etc. From the

lowest attainable temperatures to the highest temperatures at which a gas thermometer may be employed the latter instrument is used to

establish the absolute scale of temperature. For temperatures above

the range of the gas thermometer use is made of certain well-established radiation laws. These methods of reproducing the temperature scale each time it is to be used are too elaborate for practical

purposes. A number of fixed and accurately reproducible temperatures, such as the melting points of pure metals and the boiling points

of certain pure substances, are, therefore, carefully determined on the

standard scale of temperature, as defined above, and these fixed points are subsequently used for reproducing the working-temperature scale. The use of such fixed points is illustrated in the following section on

standard temperature samples. A paper has been prepared in which

are discussed the most important available data relating to fundamental determinations of important fixed points suitable for a defini- tion of the standard working scale of temperature. Values accepted

by this Bureau for the definition of its temperature scale are considered in detail, together with methods of interpolation of the temperature scale between these fixed points and the extension of the

scale to the highest temperatures.

Standard Samples for Thermometric Fixed Points.

The Bureau issues samples of various metals the melting or freezing

points of which have been determined with high precision on the basis

of the temperature scale defined as discussed above. By this means

the fundamental temperature scale may be distributed to the industries, arsenals, navy yards, universities, and technical laboratories.

The demand for these standard samples has been so great that metals

are now procured in ton lots when possible. One ton of lead, one ton

of copper, and several hundred pounds of zinc and tin have been

secured this year. This material is carefully sampled and accurate measurements of the melting points obtained. One ton makes about

1,000 standard samples. A paper has been prepared describing the

various samples issued, the chemical analyses, and the methods employed for determining the melting points.

HEAT MEASUREMENTS.

(Measurement over a wide range of temperatures of thermal properties of materials, such as specific heats, latent heats, pressure-volume-temperature relations for liquids and

gases ; heats of reaction, particularly heats of combustion of solid, liquid, and gaseous

fuels ; heat transmission and thermal conductivity : development of calorimetric apparatus and methods : and of methods for temperature control, pressure measurements, measurement of heat transmission, etc.)

Standard Heat Samples for Use in Calorimetry.

These samples of certified heating value are used in the standardization of fuel calorimeters. The materials issued were naphthalene,

benzoic acid, and sugar. The stock of benzoic acid was exhausted
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 101

several years ago, and until recently no satisfactory material to re- place it had been obtainable. The stocks of benzoic acid and naphthalene were renewed and standardized during the year. Properties of Methane.

One of the investigations having a military application which was

undertaken, by the section was the determination of a number of

the thermodynamic properties of methane. The knowledge of these

properties was very urgently desired by the Bureau of Mines, which was in charge of the production of helium on a large scale for use

as a noninfiammable balloon gas as a substitute for hydrogen. This

project, which constitutes a brilliant engineering achievement, depended on the recovery of the small helium content of certain natural

gases. Systematic surveys had shown helium to exist in such

amounts as to render this hitherto rare element available in such enormous aggregate quantities as to make its use for military

balloons and dirigibles perfectly feasible, if the recovery could be

eflfected at a tolerable cost. The design and operation of the machinery to effect this recovery

most efficiently required a knowledge of the properties of the chief

constituent of the natural gas, namely methane.

The properties of methane which were determined by this sec- tion were the following: Latent heat of vaporization, specific heat

of saturated liquid, specific heat of gas, specific volume of liquid,

specific volume of gas, and vapor pressure. Inasmuch as the accurate measurement of thermodynamic properties of fluids is extremely difficult at best, and, furthermore, as the

temperature range throughout which these properties of methane

were of interest was far outside the customary range—namely, from

200° to 300° F. below the freezing point of water—the research was

taken up with caution and reserve as to the probability of its yielding definite results early enough to be of use to the helium project.

The urgency of the need for the data, combined with the fact

that anj' progress in this comparatively neglected but important

field of research would have an intrinsic industrial value, made the

attempt seem advisable.

A method for control of low temperature which could be applied

to methods of heat measurement was developed, apparatus designed

and constructed, defects discovered and remedied, and technique

of manipulation acquired in this range of physical measurement.

The outcome has been remarkably fortunate in that not only were

reliable figures obtained for most of the important properties of

methane, but also valuable progress and experience have been ac- quired which constitute an opportunity for continuation of similar

work on other substances, in order to obtain thermodynamic data of

importance in technical and scientific work.

As examples of the numerous details in technique of physical

measurements involved in this research, wherein especial developments were established, the following two may be noted briefly

:

A Calorimeter Envelope or Containing Vessel for Conserving the

Heat of a Calorimetric System at Low Temperatures.

This calorimeter envelope is of copper and is hermetically sealed so

as to permit evacuation. It is brought to the desired low temperature

and controlled by a stream of air, cooled by expansion, tempered by
102 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

an electric heater, and led through a complex laborinthine tubular net- work which effects uniform temperature distribution, thus enabling

heat losses to be annulled. This is a novel method for thermal control

of a calorimeter envelope.

An Experimental Study of Methods for Measuring Specific Heat of

Gases.

This particular branch of calorimetry is of especial difficulty, owing

to the relatively low heat capacity of a given volume of gas, and the

most promising method is to pass a rapid stream of gas at a constant

i-ate thi'ough an apparatus called a flow calorimeter, in which the

temperature is measured both before and after the addition of a measured quantity of power electrically supplied, the system being

so constructed as to avoid unmeasured losses of heat during the process. Several designs of such apparatus suited to low-temperature

work have been evolved, constructed, and studied with favorable re- sults as to the prospective ultimate perfection which will permit specific heats of gases to be measured with facility and with definite

accuracy.

Properties of Ammonia.

An extensive series of measurements of the vapor pressure of am- monia was completed during the year. The precision obtained in

these measurements was high, values being consistent to 0.01° C. or

better, except at the lowest temperatures. It is believed that the re- sults obtained are sufficient to meet the demands of engineering and

scientific work for many years to come. The range of temperatures

covered is from —75° C. to +70° C., which is beyond the range re- quired in refrigeration engineering. The results are being prepared

for publication.

With the completion of this work there are available, for the first time, complete experimental data on the properties of liquid ammonia

and its satvirated vapor, to replace the meager and unsatisfactory

data pre^'iousl}^ available for the calculation of tables of the properties of ammonia.

High-Pressure Gauges.

A 15-atmosphere mercury manometer and a 100-atmosphere piston

gauge, constructed several years ago, have been used in several series of measurements during the year and have been intercompared within

the range of pressures of the mercury manometer. The piston gauge

in particular has been found to be capable of very precise measurements. While this satisfactory performance depends upon good design and correct manipulation, it is nevertheless true that the satisfactory performance depends upon the accuracy with which piston and

cylinder are made and fitted to each other, more than upon any other

single factor. This very excellent work was done in the Bureau's in- strument shop. A description of the gauges and the methods of cali- bration and use is being prepared for publication.

Gouy Thermoregulator.

This type of regulator, described by Gouy in 1897, appears to have

been very little used, although in many cases great improvement in

thermostatic control can be obtained by its use. The essential feature

consists in controlling the electric heating current through an oscil- lating contact instead of the fixed contact usually employed. The de-
KEPOBT OF DIEECTOE OF BUREAU OF STANDARDS. 103

vice has been extensively used in the laboratory during the year, and

a paper calling attention to its usefulness and to some of its characteristics has been preparedCaptive Balloons.

The section cooperated with the Science and Kesearch Division of

the Signal Corps (and later with the Bureau of Aircraft Production) in certain important tests relating to captive balloons.

Special Heat Tests. Tests were made for the Inventions Section of the General Staff

of the Army of a small refrigerating machine under consideration

for use in cantonments, also of a number of oil burners designed for

use in Army cookstoves. The thermal conductivities of a number of

samples of lubricating oil were measured in connection with the

lubrication investigation being conducted at the Bureau.

THERMODYNAMICS.

(Consultation and research work in technical physics or the physics of mechanical en-

<?ineering, in particular, applied hydro, aero, and thermo dynamics.)

Efflux of Gases Through Small Orifices.

An important industrial method of metering natural gas requires an auxiliary determination of the specific gravity of the gas. The

usual method of determining the specific gravity is dependent on the

time of efflux through small orifices. This method was found to be

subject to large errors. An elementary theory of the effects of viscosity and thermal conductivity of the gas upon the time of efflux was

developed and applied to the observations and shown to account for

most of the observed facts. A paper under the above title, prepared

in cooperation with a member of the chemical division, has been approvecl for publication.

Hydraulics.

A theoretical investigation has been undertaken of the resistance

of pipes and Venturi meters to the flow of water and other fluids,

concerning which there is need for a more systematic general stud}^

and analysis of the available experimental data than has yet been

published. In the study of Venturi water meters a probable explanation has been found of a puzzling anomaly observed in the behavior

of Venturi air-speed meters, which may lead to the improvement of

these instruments.

Dimensional Methods as Applied to Physical Problems.

In all of the work of this section material is continually being col- lected for a publication on the dimensional methods of attacking

problems in technical or engineering physics. This very useful

method is fast coming to more extended employment, but there is no

textbook or treatise on the subject, although one is needed. It is hoped that this want may be supplied.

Heat Transfers.

Some time has also been devoted to the question of planning for

research in heat transfer for the subcommittee on this subject of the

American Society of Mechanical Engineers, of which the chief of the

section is a member.
104 REPOKT OF DIRECTOR OF BUREAU OF STANDARDS.

LOW TEMPERATURES.

(Production of low temperatures down to those of liquid hydrogen [ultimately liquid helium] ; pref)aration and storage of pure gases ; development of methods of producing and maintaining low temperatures ; liquefaction and separation of gases at low temperature ; special tests requiring the facilities of the low-temperature plant.) Operation of Plant.

The liquid-air plant has been operated once or twice a week.

Since the liquid air can be stored for several days, this has made it possible to keep a supply in stock the greater part of the time. It has been used for investigations in the low-temperature laboratory,

and supplied to various other laboratories at the Bureau, and also

furnished to a nmnber of other institutions in Washington and the

vicinity.

The carbon-dioxide, low-temperature system was operated almost

dail}^ to provide cooling for thermometer comparators, the investigation of refrigeration constants, the testing of aviation instruments, and other investigations.

The large, high-pressure air compressor was employed not only

for the production of liquid air, but also to supply compressed air

for the production of low temperatures in the apparatus of the

thermal-expansion laboratory, the development of new oil-burning

apparatus, and other purposes.

Generators for acetjdene, hydrogen, and oxygen were maintained

in operation, and these gases were supplied to other laboratories.

Liquefaction of Hydrogen.

During the year a new electrolytic h}''drogen generator, two gas

holders, each of a capacity of 90 cubic feet, and a four-stage hydrogen compressor were installed. As soon as some additional equipment, such as pumps, purifying trains, etc., are secured, means will

be available for the efficient production of liquid hydrogen in considerable quantities.

Air Liquefiers.

Two small air liquefiers were constructed for the Bureau of Mines

for use in connection with the work on the helium project.

Methane Investigation.

The investigation of the thermal properties of methane, undertaken on account of its impoi'tance in the production of helium for

use in balloons, which investigation is described elsewhere in this

report, is being carried out in the low-temperature laboratories with

the use of the equipment where available.

FIRE RESISTANCE OF MATERIALS AND FIRE PREVENTION.

(Standardization of fire tests; fire tests of structural materials and structures; In- vestigations to develop engineering data relative to the fire-resistive features of building construction ; investigation and testing of fire-retarding devices ; investigation of building codes and fire codes ; cooperative work on fire prevention.)

Fire-Resistive Properties of Structural Materials,

The object of the investigations on the fire-resistive properties of

structural materials is to furnish architects, construction engineers,

builders. State and city building bureaus, insurance interests, and

others with fundamental engineering data relating to the behavior
REPORT OP DIRECTOR OF BUREAU OF STANDARDS. 105

and safety of various types of building material and construction

when exposed to diffei-ent conditions met with in fires. Fire Tests of Building Columns.

Tests Completed.—The series of fire tests of building columns

conducted jointly by the National Board of Fire Underwriters, the

Associated Factory Mutual Fire Insurance Cos., and the Bureau

of Standards was completed during the _year. The whole series consists of 106 tests of columns, 76 of which were made prior to July 1, 1918, and 30 during the half year ending December 31, 1918. During

the latter period fire tests were conducted on 8 structural-steel col- umns protected by hollow clay tile or solid gypsum block, 1 unprotected cast-iron-pipe column, and on 6 timber columns, 4 of which

were tested unprotected and 1 each protected by plaster on metal

lath and by plaster board. Fire tests, followed by water application, were made on 15 columns, representative in type of section and

method of protection of those tested in the main series. Purpose.—The piirpose of this investigation is to ascertain (1) the

ultimate resistances against fire of protected and unprotected col- umns as used in the interior of buildings; (2) their resistance, when

in a highl}'^ heated condition, against the impact and sudden cooling

from hose streams. While columns form the most important element in the strength

of a building, few representative tests have been made to determine

their ability to support loads when exposed to fire, and fire experience

has only a limited value, due to many unknown variables involved.

As a consequence, wide differences in requirements relating to the

protection of columns against fire exist between different municipal

codes and other published regulations. This investigation was undertaken to obtain information on which proper requirements for

the various types of columns and protective coverings can be based.

Scope of Tests.—The fire-test series includes (1) tests of representative types of unprotected structural steel, cast iron, concrete-filled

pipe, and timber columns; (2) tests wherein the metal was partly

protected by filling tlie reentrant portions, or interior, of columns

with concrete; (3) tests wherein the load-carrying elements of the

columns were protected by 2-inch or 4-inch thicknesses of concrete,

hollow clay tile, clay brick, gypsum block; as, also, single or double

layer of metal lath and plaster ; (4) reinforced-concrete columns with

2-inch integral concrete protection.

The covering materials for each class of protection were obtained

from the main producing regions of the country, the object being

to include samples from the principal types of materials that find

general application in building construction. The column coverings were applied by experienced men in accordance with plans and specifications drawn to secure average results obtainable under orclinarj'

commercial conditions. A large number of auxiliary tests of constituent materials were made, including several hundred compression

tests on the concrete emj^loj^ed.

Method of Testing.—The test columns in this series were designed for a Avorkmg load of approximately 100,000 pounds, as cal- culated according to accepted formulas, the amount varying some- what for the different sections. This load was maintained constant on the column during the test, the efficiency of the column or its
106 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

covering being determined by the length of time it withstood the

combined load and fire exposure. The latter was produced by placing

it in the chamber of a gas-fired furnace whose temperature rise was

regulated to conform with a predetermined time-temperature relation. The temperatures of the furnace and of the test column were measured at several points with thermoelectric pyrometers, and the

deformation of the column due to the load and the heat was measured

on two opposite sides over a 37-inch (94 centimeter) gauge length.

In the fire and water tests the column was loaded and exposed to

fire for a predetermined period, at the end of which the furnace

doors were opened and a hose stream applied to the heated column,

the duration of the application and pressure at the nozzle varying

with the length of time the corresponding type of column withstood

the regular fire tests. Summary of Results.—^Under the conditions of the fire test the

columns sustained their loads for periods varying from 11 to 35

minutes for the unprotected steel, cast iron, and pipe columns to over

eight hours for some of the heavier concrete protections and reinforced-concrete columns. This proves that unprotected columns are unsuitable for use in locations where fires are possible, and that adequate protection can be obtained by the use of moderate amounts of

covering material, properly selected and applied. Large variations were found in the effectiveness of material within a given class, such

as between protections of concrete made with different aggregates

and of hollow tile from the different types of clay. The method of

application was also a large factor in the result, particularly in the

case of the protections applied in the form of units or blocks. Duplicate fire tests made with columns protected by coverings of the same

material and design gave fairly consistent results, the maximum

variation from the average value being within 10 per cent for the

protections cast or poured in place and within 20 per cent for those

built up of units or blocks.

No column failed in the fire-and-water test series, the principal

effect of the fire-and-water application being to loosen or carry away

more or less of the covering material.

The preparation of the test results for publication is now in an advanced stage.

Strength of Metals at High Temperatures.

A brief description of an apparatus built for determining the compressive strength and elastic properties of materials as affected by

heat was given in the last report. During the year a number of trial runs have been made to test out various details of the equipment

and some initial tests completed on specimens of structural steel in the form of standard rolled shapes. These indicate that under

constant load of 10,000 pounds per square inch failure occurs at about

575° C, and the limit of utility from the standpoint of further use

as a structural member is reached at 500° C. Increasing the load to 20,000 pounds per square inch depresses both points very nearly

75° C. The work is being continued and will include tests of cast iron,

concrete, and timber.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 107

Pyrometer Lag.

With the types of pyrometers used for determining the temperatures in furnaces, and used in fire tests of building constructions,

large errors due to the lag of the pyrometer with rising or falling

temperatures are usually incurred. The lag is the difference between actual and indicated temperatures, and varies with the rate of temperature change and the type of mounting employed. In fire

tests, the temperature rise of the furnace during the first part of the

test is very rapid, duplicating in this respect conditions generally

present in building fires. Inasmuch as some materials used in struc- tural members and their protections sustain severe damage when subjected to rapid heating, it is important to be able to determine the

actual temperatures present in given tests, and, from the point of

standardization, to be able to produce a predetermined fire exposure

with a given furnace and pyrometer equipment.

During the year a beginning has been made in developing methods

for determining the lag constants of furnace pyrometers. The problem is complicated by the varying character of the heat influences

to which they are subjected and the difficulties incident with their

duplication in a calibrating furnace.

Fire Tests of Concrete Columns.

In this investigation, 28 full-sized building columns of reinforced

concrete have been made, 25 have been subjected to the combined

fire-and-load test, and 7 have been tested cold, in compression, in

the 10,000,000-pound testing machine.

The work done during the year has been twofold in nature, consisting of the m-aking and testing of full-sized building columns of

reinforced concrete from aggregates which had not previously been

included and in making and testing columns with protective material

other than concrete. It has been found that columns made from the

so-called Cow Bay gravel—a mixed gravel containing a large proportion of granite pebbles and gneiss pebbles—and columns made

from pure quartz gravel gave somewhat poorer results than columns

from Pittsburgh gravel previously tested. In the later column tests the protective concrete spalled so badly estvlj in the fire test that a large part of the protective covering, after breaking up into slabs,

fell away from the column, exposing the steel and the load-bearing

concrete to the fire. These columns failed, under their working load,

before the completion of the four-hour fire test. Columns in which

the coarse aggregate was trap rock showed no tendency to spall or to crack seriously in the fire tests and retained more than half their

original strength as determined by load tests made while the columns

were at maximvim temperatures at the end of the four-hour fire test. The results shown by columns in which the coarse aggregate was

blast-furnace slag were similar to those with the trap-rock aggregate.

Experiments on Methods of Column Construction and Protection.—

Since it has been found that columns from gravels of three different

types are much less reliable as to resistance to fire than columns of

limestone, trap rock, or blast-furnace slag, an effort has been made to develop practical methods whereby columns from gravels of these

types, which are in very extensive use, can be so protected as to resist

fire, as well as, or better than, columns from the other aggregates
108 REPORT OF DIRECTOR OF BUREAU OF STANDAHDS.

without additional cost in construction. Columns have been cast in

gypsum forms which were used to serve the double purpose of doing

away with the somewhat excessive cost of steel or wood forms and

of remaining in place to serve as protection against fire. Forms of

this sort, with a light binder of expanded metal or of poultry netting, have been found to stay in place throughout the four-hour fire test and to afford excellent protection. Gravel-concrete columns so protected came through the four-hour fire test much better than trap

rock and slag-concrete columns made in the usual way.

It has been found that columns could be made without the usual

steel or wood forms by wrapping metal lath around the spiral reinforcing steel and casting the concrete in that. The results obtained

indicate that no great difficulty should be experienced in making

columns in this way if concrete of medium consistency is used.

Protective Plasters.—Several columns have been made and tested

in which a part of the protective covering has been supplied in the

form of plaster from Portland cement and sand. These columns

gave better results than gravel-concrete columns from the same aggregate, made in the usual way, but not as good as those made from

trap rock and slag in the usual way. The trouble with this form of

protection is that the outer coat, or coats, of plaster fall off under

fire conditions, leaving the column with insufficient protection.

Considerable work has been done in the study of plasters for the

protection of gravel-concrete columns and for other purposes. It has been found that, within certain limits, mixtures of gypsum, hydrated lime, and kieselguhr give workable plasters of superior heatinsulating properties. One column which had been cast in expanded

metal over spiral reinforcement was covered with approximately 1 inch of a mixture of these materials. Poultry netting was placed

over the second coat and concealed by the third coat. A finish coat of gypsum and hydrated lime was used. In the fire test only the

finish coat came off. The total thickness of protective material on

this column was approximately 1^ inches, and the effectiveness of

the thermal protection was such that the highest temperature meas- ured in the steel was 185° C., as against 410° C. in the steel of col- umns protected by 2^ inches of material in the form of concrete covered by cement plaster.

Fire Prevention.

The section has cooperated, by conferences and correspondence,

with Federal, State, and local agencies in matters relating to safety

to life, fire protection, and fire prevention.

These conferences related to such matters as fire hazards in various

industrial processes, such as cotton ginning, storage and shipment of

fertilizers, storage and shipment of petroleum products, pyroxylin

plastics, including motion-picture film, etc. Complete inspections of the properties and occupancies of the

Bureau of War Eisk Insurance were made at the request of that

bureau, and a report was rendered on the fire hazards involved, with

especial reference to the safe storage of documents.

A member of the section has participated in committee work of

the National Fire Protection Association, the Fire Marshals' Association, the National Safety Council, and other organizations interested in fire prevention and the reduction of fire waste. Considerable
KEPORT OF DIRECTOR OF BUREAU OF STANDARDS. 109

work has been done in cooperation with the first of these associations

in matters relating to exits from buildings where large numbers of

people are housed.

The section cooperated with a committee of the various branches

of the War Department in the preparation of standardized specifications for fire extinguishing and signal apparatus and supplies.

AUTOMOTIVE POWER PLANTS AND THE FUELS AND LUBRICANTS

THEREFOR.

(Investigation of the fundamental, seientifiCj and technical problems related to the de- sign and operation of internal-combustion engines and accessories, and the qualities and

characteristics of fuels, lubricants, etc., for use in such engines.)

. During the first half of the year the work was limited to the immediate necessities of the military departments of the Government and was confined to specific questions of the performance of particular

engines and accessories, fviels, lubricants, etc. While carrying out

these tests data were obtained which were known to have important

bearing on the more fundamental questions relating to internal-combustion engines and which are generally conceded to be of great importance in the economic development of the automotive industry

of the country.

When the signing of the armistice afforded relief from the pressure

of hurried tests and tentative analyses, the facilities of the laboratory

and the time of the staff were turned toward the fundamental questions and the review of the data obtained earlier as a by-product.

The topics described below, therefore, parallel very closely the ones

listed under this subject in the previous annual report. The advance

to be recorded is the marked progress in correlation of the work and

its reduction to a form in Avhich the results are available to the auto- motive industry.

Ignition.

A comprehensive investigation of spark plugs and ignition appliances, commenced in 1916, has been continued, and the -results so far

attained have been communicated to manufacturers and users of such

apparatus, who have shown most gratifying appreciation. The

printed reports will shortly be available to the general public in the

fourth annual report of the National Advisory Committee for Aeronautics, under whose auspices most of the investigational work was

conducted by this section, with the active cooperation of the elec- trical and ceramics divisions of the Bureau. These reports, seven

in number, are entitled " Spark Plug Defects and Tests," " Properties and Preparation of Ceramic Insulators for Spark Plugs," " Effect of Pressure and Temperature on the Sparking Voltage," " Heat

Energy of Various Ignition Sparks," " Temperature in Spark Plugs

Having Brass and Steel Shells," " The Subsidiary Gap as a Means

for Improving Ignition," " Characteristics of High-Tension Magnetos." Each one of these reports is made up of several small reports

dealing with a particular phase of the general investigation.

An investigation of the properties of insulating cables in ignition

systems was completed. A comprehensive series of oscillograph photographs of magneto-wave forms was obtained and is available for

inspection, but not for reproduction and general distribution.
110 REPORT OF DIRECTOR OF BUREAU OF STANDARDS,

Radiators.

The experimental work of the past two years, conducted largely

under the auspices of the National Advisory Committee for Aeronautics, has been compiled in seven reports, which will shortly be

available to the public in the fourth annual report of that committee, under the following titles : " Synopsis of Aeronautic Radiator

Investigations for 1917-18 " ; " General Analysis of Radiator Problems " ; " General Discussion of Test Methods for Radiators "

" Head Resistance Due to Radiators " ; " Effects of Altitude on Radiator Performance " ; " Results of Tests on Radiators for Aircraft

Engines " ; " Some Problems of Radiation," each of which deals with

a number of specific problems in this particular line. The laboratory measurements have been completed on flat-plate

radiators, fin and tube radiators, and whistling radiators. The ef- fect of yaw on head resistance and heat dissipation has been studied.

An analysis of the best proportions in radiator design to accomplish specified results is in progress. This Avill enable manufacturers to apply directly the results of two years of scientific work

relating to the most important features of radiator design and construction.

Much experimental work is still in progress to determine more

completely such fundamental data as pressure drop of the air

through different types of radiator tubes, temperature distributions,

measurement of mass flow of air, etc. Theoretical investigations are under way relating to air-cooled engine cylinders and to increased

radiator requirements imposed by the use of superchargers on air- craft engines.

Altitude Laboratory.

The Bureau has the only " altitude laboratory " constructed to date in this country. This is a small room with reinforced-concrete walls strong enough to withstand the pressure produced on

the outside by exhausting the air within to a pressure as low as one-third atmosphere. The engine under test is mounted on a

suitable stand within this chamber. The air supplied the engine

at these low pressures is also cooled in order to reproduce as closely

as possible atmospheric conditions existing at high altitudes. Aviation engines have been operated in this chamber simulating flight at over 30,000 feet, but under conditions permitting of careful scientific measurements. Comprehensive tests were made of the per- formance of sample engines in advance of quantity production for

the purpose of selecting suitable manifolds, carbureters, etc., with

respect to performance under flight conditions. Information obtained in such tests had an important bearing on the selection of

the equipment for the Hispano-Suiza, type E, aircraft engine. A

careful study was made of the performance, under altitude conditions, of the well-known " Liberty 12 " engine. A description of

this laboratory and the more general results obtained in it have

been collected in a series of four reports which are being published

by the National Advisory Committee for Aeronautics in their fourth

annual report under the following titles: "Effect of Compression

Ratio, Pressure, and Temperature on Power"; "A Study of Airplane-Engine Tests " ; " Power Characteristics of Fuels for Aircraft

Engines"; and "Description of Altitude Laboratory."
EEPORT OF DIKBCTOR OF BUREAU OF STANDARDS. Ill

The hastily constructed altitude chamber, housed in a temporary

stucco shed, which met the immediate needs of the military work,

is being replaced with a better-designed chamber in a permanent

brick structure. Provision has been made in this laboratory for

equipment which will be available for work of interest to the auto- motive industry of the country. The constructional work on this

building is now nearing completion, but the equipment is not fully

installed.

Flame Propagation in a Gas-Engine Cylinder.

A method for the measurement of the rate at which the flame is propagated in an engine cylinder while operating under service

conditions has been developed in cooperation with the electrical

division of the Bureau and has proved successful. The preliminary

results obtained by this method of measurement indicate a speed

of propagation less than that commonly assumed by designing engineers, and the final results, when available, will have an important

bearing on engine design.

Pressure Cycles Occurring in Gasoline Engines.

Indicators for the measurement of the pressures in heavy, slowspeed engines prove useless on the light, high-speed engines for

aircraft, because of inertia of their moving parts. Two new in- dicators are being developed with much promise of success. The

successful development of an indicator suitable for use at high

speeds will provide a most useful instrument in the development of

high-speed, internal-combustion engines.

Carburetion.

This work is part of an extended program, including the fundamental physical questions concerning vaporization and atomization

of fuels in carbureters, engine manifolds, and cylinders; apparatus

has been designed, constructed, and used for the purpose of studying the metering characteristics of both airplane and automobile

carbureters as affected by barometric pressure, rates of air flow, air

temperature, engine speed, etc. With a view to the determination

of the fundamental principles of operation, an investigation has been

made of the relative performance of various methods for the auto- matic and inherent compensation for changes in metering characteristics with change in barometric pressure ; that is, altitude.

Two papers collecting results of this experimental work have been

completed and transmitted to the National Advisory Committee for

Aeronautics for publication in their fourth annual report under the

titles, " Carbureting Conditions Characteristic of Aircraft Engines "

;

" Metering Characteristics of Carbureters."

Effect of Water Injection on Gas-Engine Performance.

An extensive although still incomplete series of experiments on

this subject has been made. The results so far obtained show no

appreciable gain in power or energy with water injection. The re- port of these experiments has been communicated to the National

Advisory Committee for Aeronautics, which will publish it in their

fourth annual report.
112 BBPOKT OF DIRECTOR OF BUREAU OF STANDARDS.

Tests of Special Engines and Accessories.

Numerous special tests were conducted during th.e year, including one on a small, direct-injection, Marburg, heavy fuel engine, a "barrel" type engine, and a special 16-valve-head Ford engine, and

two battery-charging sets, tested for the Signal Corps for reliability.

A specially designed mercury-cooled exhaust valve has been found

very successful in a Hispano-Suiza aircraft engine and will help to solve a problem of special importance in an engine of this type.

Petroleum Conservation.

From the beginning of the war the work of the Bureau of Mines

on automotive-fuel conservation was actively supported by the

Bureau of Standards through close and constant cooperation. At

the meeting of the Interallied Commission on Specifications for

Petroleum Products of the Interallied Petroleum Conference some

of the delegates from our Allies urged a very rigid gasoline specification for fuels for use in combat aircraft, basing their recommendations on their own satisfactory experience with certain gasolines,

but without full knowledge of the possible performance of other

gasolines. The adoption of such close specifications would have materially reduced the available supply of combat aviation gasoline and

introduced unnecessary expense and serious difficulty, not only in

production but in overseas shipment and distribution. A careful

comparison of the power-producing qualities of 10 different gasolines selected through cooperation with the Burea\i of Mines was made by actual engine tests under flight conditions in the altitude

laboratory of the Bureau. A report on these tests was the only

quantitative data presented to the Interallied Commission on this

subject, and it resulted in the adoption of more liberal gasoline specifications, which were amply justified in service and which resulted

in a saving to the Ajnerican people of millions of gallons of oil in

their fields and thousands of dollars waste effort in the refining and

distribution in France of aviation gasoline.

Fuel Comparisons, Fuel Savers, and Kerosene-Burning Devices.

In addition to service tests on common and aviation gasolines a number of sjmthetic fuels were tested at the request of the Bureau

of Mines and the Navy Department, respectively. Reports were

prepared on the performance of "Hector" fuel, a mixture of 70

per cent cyclohexane and 30 per cent benzol developed by the Bureau

of Mines, and "Alcogas," a fuel containing a large percentage of

alcohol. The general conclusions from these tests will be compiled

for publication. Five proprietary preparations intended to be used

as gasoline substitutes were tested for the military service. Many

of the so-called " gasoline improvers " were tested for the Invention:-

Section of the General Staff of the Army. Two devices for the con- venient use of kerosene instead of gasoline in the usual gasoline

engine have also been tested for this section.

Lubrication.

The work on the general subject of lubrication has been carried on

under the supervision of an oil committee representative of the Automotive Power Plants Section, the miscellaneous materials section,

and the Chemistrj' Division.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 113

Lubrication of Internal-Combustion Engines.

Prompted, by the desire of overcoming lubrication difficulties ex- perienced in airplane engines, the Bureau of Aircraft Production

initiated at the Bureau of Standards a thoroughgoing investigation

of lubricating problems. A complete program was drawn up to cover the entire complex situation to be investigated and a new

laboratory was equipped for the purpose. The work done in this

laboratory up to the end of the fiscal year has been confined largely

to apparatus design. Some of the investigations planned have beeti begun, but no completed results can be reported.

The following apparatus necessary partly for routine tests and

partly for new investigations has been completed and is now in use

:

Oxidation oven for commercializing the Waters' oxidation test; Herschel emulsifier for making demulsibility tests; apparatus for

measuring gasoline absorption ; battery of Saybolt viscosimeters

provided with electric heating and thermostatic temperature control ; vacuum-distillation apparatus for lubricating oils. Standardization of Instruments.

In continuation of the work of viscosimeter comparisons, the

Ubbelohde viscosimeter has been investigated and the viscosity of

various samples of gasoline determined. This work is described in Technologic Paper No. 125. The Redwood viscosimeter is now under

investigation.

The Bureau's report on the " Tag " closed flash-point tester was

published by the American Society for Testing Materials, as an appendix to the report of the committee on preservative coatings for

structural m.aterials, and was presented at the annual meeting of the

society, June 24-27, 1919. Friction Machine.

Considerable work has been done to determine the relation be- tween viscosity and friction and the conditions necessary to obtain

reliable results with friction machines. This work is being continued. A new friction machine for the particular purpose of studying the lubrication problems arising in connection with internalcombustion engines has been completely designed and is in process

of construction.

Routine Physical and Chemical Tests. The ordinary physical and chemical tests of lubricating oils, consisting chiefly of the determination of the viscosity, flash -point, fire point, pour point, demulsibility, acidity, percentage of fat, and per- centage of ash, have been made according to generally accepted

methods on many samples submitted by Government departments.

Oils for internal-combustion engines and for other special uses were

also tested by Conradson's method for carbon residue, as well as by

the Waters' method for the carbonization value. The latter method

was developed at the Bureau.

During the year physical tests were made of 529 samples of lubri- cants and chemical tests of 557 samples.

142289—19 8
114 KEPORT OF DIRECTOR OF BUREAU OF STANDARDS.

4. LIGHT AND OPTICAL INSTRUMENTS.

[Spectral analyses; measurements of standard wave lengths; aerial photography;

standards and testing of sugar and other materials by optical means ; general polarimetry

color measurement and specification of color standards; spectral transmission and reflec- tion of dyes and other materials ; design and testing of optical instruments ; testing of optical glass; radiometry ; investigation of dispersoids ; interferometry.]

SPECTROSCOPY.

(Spectroscopic investigations of metals, rare earths, and rare gases; red and infra-red investigations of the atmospheres of the sun and the earth ; development of infra-red photography for aerial observations.) Red and Infra-Red Spectra of Chemical Elements.

The principal work of the spectroscopic laboratory is the determination of standards of wave length in the spectra of the chemical

elements. Because of its experience in the use of photographic plates

sensitized to red and infra-red light, it has devoted considerable

attention to the investigation of these long wave regions of the spectra

of the chemical elements. Although the greater portion of the time

and energy was devoted to war problems described below, yet considerable progress was made in spectroscopic research. The investigations of the red and infra-red spectra of silicon, titanium, vana- dium, chromium, manganese, molybdenum, tungsten, and uranium

reported last year as being in progress are now completed, and the

data have been collected for publication. Similar studies of the rare

gases krypton and exnon have been completed and are now in press. The investigations of zinc, cadmium, mercury, aluminum, tin, lead,

antimony, bismuth, silver, and gold are nearing completion, and in- vestigations of the rare-earth elements yttrium, lanthanum, cerium,

samarium, thorium, erbium, etc., have been started. Applications to Astrophysics.

The study of the red and infra-red spectum of the sun mentioned

in the last annual rejport has been completed. Additional spectrograms on plates bathed with pinacyanol and dicyanin have been' secured with the Porter spectrograph of the Allegheny Observatory.

These plates have been measured and reduced and the results, are now

in process of publication. Briefly, it has been found that in the

portion of the sun's spectrum comprised between the limits 6,500A

and 9,O0OA there are more than 2,400 Fraunhofer lines. Of these

nearly 60 per cent are produced by the earth's atmosphere, the re- mainder being of solar origin. Over 500 of the 900 lines due to absorption in the sun's atmosphere indicate the presence of 27 chemical

elements whose spectra have been investigated in the red and infrared regions.

Spectroscopic Analyses.

Spectroscopic analysis affords a rapid and accurate method of

examining minerals, ores, metals, alloys, and various compounds for

which a qualitative analysis is desired. In some cases it is also possible to make quantitative analyses as well. During the year the

following substances have been analyzed spectroscopically : Five

samples of tungstic oxide, smokeless gunpowder of German and

American manufacture, five samples of ores containing zirconium, six

samples of barium chloride, two samples of gallium, two of tin, and

one of very pure magnesium wire. In addition to the above sub-
KEPORT or DIKECTOE OE BUEEAU 0"F STANDARDS. 115

i stances, whose arc or spark spectra were pliotographed for purposes

of analysis, low-pressure tubes containing samples of " C " gas used m

filling dirigible airships were made and their spectra examined.

This gas was found to be chiefly helium contaminated with air. False Spectra Produced by Gratings.

In the course of the investigations on the infra-red spectra of

various metals it was noted that many lines of apparent wave length

greater than 10,000A corresponded to lines of shorter wave length

in the visible red region of the spectrum. The ratios of the wave

lengths of the visible red lines to the corresponding lines in the

infra-red region were found to be constant and to be of four values

;

that is, each line produces at least four false lines or " ghosts " at remote distances from the exciting lines. The existence of " ghosts " near the exciting lines and of the remote ones discovered by Lyman

in the ultra-violet has been known for some years. These discovered

in the infra-red may be of the Lyman type, but if so are due to a ruling error different from that in the gi-ating used by Lj'man.

Their presence has made it desirable to study the imperfections of

diffraction gratings, and accordingly the Bureau has borrowed a number of gratings ruled at the Johns Hopkins University for the

purpose of studying the nature and causes of the false spectra given

by them.

Lov7-Pressure Tubes for Spectroscopy.

The spectra of gases are studied by passing an electric discharge

through a tube containing the gases at low pressure. Frequent re- quests come to the Bureau to supply tubes for use in astronomical

and physical investigations. During the year 38 tubes have been

filled with oxygen, hydrogen, helium, neon, and mercury. Attention is called to the fact that the helium used for this purpose was

obtained from the gas wells in the western part of this country,

from which helium is taken for use in dirigibles. The helium as used

in the dirigibles is contaminated with impurities which are removed

when a tube is prepared for spectroscopic work.

Spectroscopic and Optical Apparatus.

The spectroscopic laboratory has during the year produced some

apparatus of various types to meet its own needs and the needs of

others who have come to it for assistance. To facilitate the securing

of spectrograms a new arc stand was designed and constructed and

also a new plate holder.

For qualitative work in the study of low-pressure tubes, flames,

arcs, etc., a new direct-vision spectroscope has been designed, using

glasses made by the Bureau of Standards. Also a large number of

replica gratings have been made for the same purpose. These have

been supplied to various Government laboratories, which have found

them useful in qualitative work.

A photographic lens corrected for red light has also been computed. This lens is in process of construction at present in the

optical shops of the Bureau.

Aerial Photography.

It is well known that the ordinary photographic plate when ex- posed in a camera does not reproduce exactly what the eye sees.
116 BEPORT OF DIRECTOR OF BUREAU OF STANDARDS.

This is because the ordinary plate is affected by only blue and violet

light, for which the eye is relatively insensitive, and is scarcely at all affected by the green and yellow, for which the eye has its maximum

sensitivity. These ordinary photographic plates are practically in- sensitive to red light and are therefore handled with safety in light

from a ruby lamp. It has long been known, however, that photographic plates may be made sensitive to green, yellow, and red light

by the admixture of suitable dyes to the emulsions on the plates.

A plate sensitive to these longer waves possesses some marked

advantages over the blue and violet sensitive plate. A panchromatic

.plate reproduces more faithfully what the eye sees, and when exposed

behind a ray filter or color screen it portrays objects which, on ac- count of haze, smoke, etc., would be hidden from an ordinary plate

and also gives different contrasts, depending on the nature of the

light transmitted to the plate through the filter. The phenomenon of

haze penetration by the longer waves is known to most outdoor

photographers. Not only haze due to water vapor, but smoke haze,

which looks bluish to the eye, is largely eliminated by using light of

longer wave length than that which is most effective in case an ordinary unscreened plate is used. Objects completely obscured on an

ordinary unsci-eened plate by haze or smoke may be shown in good

detail by using a panchromatic plate and a red filter. Such red

sensitive plates, of course, can not be handled in the presence of the

well-known dark-room ruby lamp, but must be developed in complete darkness or in a very weak gi-een light. To obtain the long- wave advantages of haze penetration and contrast mentioned above

the photographic plates must have the greatest possible sensitiveness

to yellow, orange, and red light if the exposure times are necessarily

short on account of rapidty moving objects or if the camera itself is in rapid motion, as is the case in aerial photography. When cor- rected camera lenses giving very bright images are not to be had it is even more necessary that the photographic plates be of the highest

possible sensitiveness.

During the war aerial observation early came to play a prominent

part, and it became a matter of great importance to have a suitable

panchromatic plate for aerial photogTaphy. Laboratories and re- search organizations in various allied countries were busily engaged

in trying to produce plates of extreme sensitiveness or speed. The

best commercial orthochromatic (sensitive to blue, green, and yellow) and panchromatic (sensitive to all colors) plates were too slow

for most purposes. For many years, however, physicists had used

3'ellow and red-sensitive plates which greatly exceeded in speed any

of the commercial plates. These plates are prepared by bathing an

ordinary photographic plate (sensitive to violet and blue) in certain

solutions of aniline dyes, and at the expense of keeping qualities

such plates may be made much more sensitive to red light than any

plate known to commerce. After several years of experience with

such plates in spectroscopic investigations by the Bureau of Standards, it seemed worth while, when the United States declared war

upon Germany, to make an application of them to landscape photography. Accordingly, experiments were made in 1917 to determine

the practicability of using the bathed plates for landscape photography, with the hope that either this method might be a useful addition to the photographic methods of our military farces or that the
REPOKT OF DIRECTOR OF BUREAU OF STANDARDS. 13 7

experiments would lead to improved coinmercial plates which incorporate sensitizing dyes in the photographic emulsions.

Preliminary tests with apparatus that was inadequate to test the

real merit of the bathed plate proved encouraging enough to warrant a continuation of the investigation with better apparatus (more

suitable cameras and ray filters) , and with new dyes of British manufacture.

The attention of the Science and Research Division of the Signal

Corps was attracted to these early results and the Bureau of Standards was given the opportunity of comparing the stained plates with

various plates used by the military forces. Among these were several

types of British-made panchromatic plates then in use on the western

front for aerial photography. A series of experiments soon showed

that pinacyanol stained plates were at least four times as fast as the

best commercial panchromatic plates then in use. In particular,

plates stained with some new dyes of British manufacture were found to be much superior to any commercial panchromatic plates

not only in speed, but also in the range of color sensitiveness.

These encouraging results led to the offer of the Bureau of Standards to supplement the photographic work of our military Air Service by adding to it a new method which would probably be of great

military importance in special photographic work, such as the penetration of haze and smoke, detection of camouflage, etc., where the

ordinary commercial plates could not be satisfactorily used. The

assurance of cooperation from the War Department was received and

the Bureau invited by the Signal Corps to test the bathed plates in

aerial photography as soon as facilities permitted. Extensive experiments were made at Langley Field during the spring and summer

of 1918 under the generous auspices of the Science and Research Division of the Signal Corps, and after the armistice was signed the

flying facilities of Boiling Field were used to a limited extent to complete the experiments.

Early in 1918 a representative of the spectroscopic section of the

Bureau of Standards who was in France was requested by the French

military authorities to assist the French photographic section in

making fast-color sensitive plates. A temporary laboratory was in- stalled similar to the ones at the Bureau of Standards, with the ex- ception that the plate-drying cabinet was arranged so as to use air

heated by a gasoline stove. This was necessary on account of the

low temperature and high humidity prevailing in northern France

in winter. The following experiments with bathed plates were made there : Ordinary fast plates were stained with pinaverdol and

pinacyanol with ammonia; orthochromatic plates were bathed in

pinacyanol with ammonia ; panchromatic plates were bathed in ammonia. Each type of plate was used in three ways—unscreened,

with a deep yellow screen, and with a red screen. The bathed plates were found to be somewhat faster unscreened than any plate actually

used by the French. Using screens, the bathed plates were shown to be much _faster, particularly for red photography. This matter was

also considered of very great importance by the American Aviation

Section, and it was requested that one of our pliysicists cooperate with

them on experiments of this kind. This cooperation was offered, but was not strongly supported by the military authorities in this country,

largely on account of the fixed idea that bathed plates had only
118 EEPOKT OF DIEECTOK OF BUREAU OF STANDARDS.

reached the experimental stage. Considering the special equipment

and technique required by such plates, their use at the battle front was held in abeyance, with the hope that commercial panchromatic

plates of sufficient speed would be forthcoming.

The success with which dye-sensitized photographic plates had

been used in the laboratories of the Bureau convinced this section of

the possibility of their being of extreme importance in special military applications and impelled the Bureau to demonstrate their value

by careful measurements in the laboratory and tests in the field. In

addition to the problems of ordinary photography the use of bathed

plates with light filters involved, (1) a study of photosensitizing dyes

and of the spectral sensitivity which they imparted to ordinary

photographic plates, (2) experiments still further to increase the

speed of color-sensitive plates, (3) investigations of the spectral dis- tribution of energy reflected from landscape, etc., (4) design and

construction of new photographic lenses for use with red light, and

other similar problems. A detailed rej^ort of this work was made

under the title of " Photographic researches."

Hypersensitizing Commercial Panchromatic Plates.

The speed and color sensitiveness of photographic plates are of

extreme importance in military photography to obtain results under

unfavorable conditions of light intensity, haze, relatively low-speed

cameras, etc. It is, therefore, obvious that a commercial panchromatic plate with good keeping qualities is, if sufficiently fast, more

economical than a stained plate. The cause of the superior speed of

the stained plate, perhaps, lies in the use of ammonia in the staining

bath. It became, therefore, a matter of interest to see to what extent commercial panchromatic plates could be hypersensitized by treat- ment with ammonia. Experiments showed that ammonia increased

the speed of various brands of panchromatic plates from two to four

times and also extended the sensitiveness to considerably longer

waves. The treatment consists in soaking the plate prior to using,

for four minutes in a bath containing 75 cubic centimeters water, 25

cubic centimeters ethyl alcohol, and 3 to 4 cubic centimeters of

strong ammonia. Plates so treated have been used successfully in

aerial photography, and also for spectroscopic work in various scientific laboratories and astronomical observatories.

Dyes for Photographic Sensitizing.

Ordinary photographic plates, which owe their sensitiveness to the silver halides alone, are sensitive only to the blue, violet, and

ultra-violet regions of the spectrum. If, however, a suitable dyestuff

be added, the emulsion becomes sensitive to .other regions, the particular region depending on the dye used. The dyestuff is applied

to the halides in one of two ways : In the commercial orthochromatic

and panchromatic plates the dyes are incorporated in the emulsion

and the mixture is flowed over the glass plate. The second method

consists of bathing an ordinary blue-sensitive plate in a dilute solu- tion of the dye and allowing the plate to dry. The dyes most valuable for sensitizing photographic plates to the longer wave portions of

the spectrum are commonly Imown as pinaverdol, pinacyanol, and

dicyanin. Pinaverdol sensitizes a blue and violet sensitive plate to the green part of the spectrum ; pinacyanol sensitizes from green to
BEPORT OF DIRECTOR OF BUREAU OF STA^TDAKDS. 119

red: and dicyauin is most efficient in iDhotography of the red and

infra-red spectrum.

Previous to the war practically all of the dyes which were most

successfully used in photographic sensitizing were produced in the

large dye factories in Germany. When this source of supply was cut

off, not only was the commercial color-sensitive plate manufacturer

put to some trouble to find substitutes for the dyes he formerly imjDorted, but the physicist also, who prepared bathed plates for

special problems, seemed likely to have to discontinue his work

becaiise of the shortage of dyestuffs.

Photogi'aphic Dye.—The spectroscopy section of the Bureau of

Standards had been making extensive use of photographic dyes in

spectroscopic work during the past five years, and attention was

called at the beginning of the European war to the importance of

making such dyes in America. Upon the entrance of our country in

the war the urgency of work on photosensitizing dyes was insisted

upon, and this work was earnestly undertaken by the chemical division of the Bureau of Standards and by the Bureau of Chemistry of

the Department of Agriculture. The spectroscopy section of the Bureau of Standards maintained close relations with this work and

cooperated by testing the photosensitizmg properties of all the samples of dyes submitted for this purpose. During the past year nearly

100 different samples of such dyes were tested, and many of them

were found equal or superior to their foreign predecessors in useful- ness for photography. Quite aside from the importance of such

excellent photosensitizing ch'es for use in military photography their

value in spectroscopic and astronomical researches of the future can not be overestimated.

POLARIMETRY.

(Standardization of materials, including suears, sirups, and other compounds, by

polarimetric methods ; precision polarimetry, including the determination of polarimetric constants : development of standard definitions, methods, and instruments : calibration of polarimetric apparatus ; standardization of the technology of sugars and related materials ; research in all factors affecting the efficient organization of sugar manufacture and

testing : sugar standards for precision-calibration purposes ; laws and principles of magneto-optics and their practical application.) The Rare Sugars.

There are now known and are being used by the Medical Service

of the War Department and the general public about 20 of the

so-called rare sugars. The demand for a highly purified dextrose

(glucose) has become so great that its production has increased to a

point where it can no longer be designated as a rare sugar, but must

be placed in the same category with ordinary sugar (sucrose).

Unfortunately, there is in existence but little scientific data on

the rare sugars, and practically all there is is inaccurate and wholly

inadequate for modern usage. Many of these sugars undoubtedly

have valuable properties unknown at this time. One of their principal uses is the differentiation of bacteria, for which purpose they

are invaluable.

During the year the Bureau has had presented for test a number

of these rare sugars. Necessarily, their investigation requires care- ful research, so that progress is slow. The demands on the Bureau

for this work are so "insistent and continuous that plans have been

drawn for a section wholly devoted to the scientific exploration of
120 REPORT OF DIRECTOR OP BUREAU OF STANDARDS.

this important field. The sugars are nearly all expensive to produce; their current values ranging • from a few dollars to $350 a pound. A number of them might have great commercial importance

if they could be produced at a reasonable cost. The results which

the Bureau has attained in this work during the past few months are most encouraging.

Production of d-Mannite.

At the request of the War Department, the Bureau has undertaken the production of a considerable quantity of d-Mannite. This

little-known sugar is utilized on an extensive scale by the Army

Medical Service. The source of supply is a crude manna. The Bureau's investigation finally developed a method whereby pure white

crystals of d-Mannite can be produced by two crystallizations from

the crude manna. It thus became possible to produce relatively

large quantities of the valuable substance at a reasonable cost. The

Bureau is now engaged in this work and will produce 1,000 pounds

of the pure material.

A New Fixed Point on the High-Temperature Scale.

The successful termination of a scientific research, no matter what

its character, almost invariably leads to an extension of knowledge

in other directions than those contemplated within the scope of the

original problem.

The investigation of the natural rotation of light by crystalline

quartz at high temperatures has developed new and unexpected

phenomena. Additional knowledge of the properties of quartz is of importance from the theoretical standpoint because of its extensive use in polarimeters and other instruments, and because of its rela- tion to problems involved in the study of the history and the formation of the earth.

At a temperature of about 573° C. crystalline quartz changes into

another crystal, with a transformation of energy during the process. The discovery made by the Bureau is that the temperature at which

the transformation starts when the crystal is being heated is a very

definite and sharply defined one. A careful investigation has shown

this point to be 573°.3 C. The transformation of energy at this

temperature is apparently far sharper and more easily determined

than that utilized in determining the ordinary points on the hightemperature scale. It is found that a thermocouple close to but not

actually in contact with a small plate of quartz will record this

point with high precision. To obtain the best results the thermocouple should be inserted in a small opening in the crystal, thereby

standardizing it at a fixed and accurately known temperature. A

study of quartz from various geogTapically widely distributed sources shows that the phenomenon is common to all crystalline quartz. Also

the temperature of 573°.3 C. is a fortunate ' one in that there is now

in existence no known method of conveAiently calibrating temperature-measuring devices in this region. Not the least important

advantage is the ease with which a thermocouple can be standardized

by the use of this method.

Natural Rotation of Quartz at High Temperature.

The investigation of the natural rotation of light by crystalline

quartz at high temperatures has been continued. As the temperature
EEPOKT OF DIRECTOR OF BUREAU OF STAITDARDS. 121

of a crystal of quartz approaches 573° C. there occurs a most profound change in all the physical pi'operties of the crystal. It has

been found that there is an especially abrupt change in the optical

properties. When light, vibrating in a single plane, is passed

through the crystal, the rotation of the plane of vibration which

ordinarily occurs in crystalline quai-tz is found to suffer an abrupt

change as the temperature of 573° is approached, the magnitude of

the change depending on the wave length or color of the light used.

When a curve is plotted, showing the variation of the rotation with

the temperature, it is found that above 573°.3 C. there is comparatively little change in the rotation for relatively large changes in

temperature. The Bureau's recent work has found that the curve

expressing this property is a straight line almost parallel with the

temperature axis from the inversion point of 573°.3 to 1,500° C. The new work has also developed the law that the relative change

in the rotation is practically the same, no matter what may be the

color of the light passed through the quartz crystal. The so-called

rotation dispersion of quartz has therefore been proved to be the same for all wave lengths at all temperatures up to the inversion

point. As stated in last year's report, the Bureau's polarimetric

measurements are the first precision measurements ever made at high

temperatures. The progress made in these studies during the past

year has made definite a new line of attack for many unsolved

problems.

Adjustment and Standardization of Polariscopes.

The Bureau has inaugurated the work of adjusting polariscopes

in addition to that incident to their standardization. This has be- come necessary owing to the fact that the sugar industry, as well as educational and research institutions, have been unable for some

time to obtain new polariscopes or to get those that they have, which

are out of order, put in serviceable condition.

Owing to the sudden expansion in the sugar industry, it became

necessary by war conditions to resort to the use of discarded instrix- ments. Many of these instruments have a different basis of calibration from those of the newer and recognized types. The Bureau

has constantly been consulted in regard to the use of these instruments and has been able to render an important service in this

respect.

In addition to the above-mentioned class of instruments, a second

class has been brought out of retirement. The latter are of recog- nized types and are excellent instruments for the manufacturers'

and refiners' use. They are, however, useless to them owing to the

fact that the optical parts are out of adjustment. In many in- stances it is found that nicols need recementing or need to be ground

and polished or cemented in their sleeves; quartz wedges are often

out of alignment or pressure may have developed on the wedges, etc. An instrument which has developed any of these defects is necessarily rendered useless until they have been corrected.

During the year the Bureau has adjusted and standardized 39

polariscopes, thus putting them in condition to render good service.

To bring about this desirable end required considerable preliminary

study and experimental work. The middle of the fiscal year had,

therefore, arrived before the Bureau was ready to receive instru-
122 KEPOKT OF DIRECTOR OF BUREAU OF STANDARDS.

ments in these classes. However, the prelhiiinary work was so successful that 39 instruments were all handled in the latter half of

the year. The scales of all polariscopes that have been sent to the

Bureau have been calibrated and certificates have been issued, based on the now widely accepted Burea^u-ef^-Standajrds' determination of

the international sugar scale.

'

Testing of Quartz Control Plates.

Quartz control plates are indispensable for the accurate daily

checking of saccharimeters. Eleven of these plates were tested and

certified for various sugar companies. Four, which were improperly

mounted in wax, were removed from their original mounts and re- mounted in loose m.etal holders in such a way as to comply with the

Bureau's specifications.

Owing to the fact that all quartz control plates have heretofore

been imported from Europe, it has been impossible to secure any for some time. With the idea of being of the greatest possible assistance

to the sugar industry in this emergency, the Bureau has abandoned

its previous practice, and whenever feasible, is remounting and test- ing discarded or improperly mounted plates in a manner to make

them serviceable. The values of a number of the Bureau's standard

plates have been redetermined and found to be in good_agreement

with the values previously assigned them^

Evaluation of the Clerget Constant. ^

/v. Sugar, in every stage of its manufacture except final one, occurs in combination with other optically active substances; that

is, substances which affect the polariscope in the same manner as sugar itself. Therefore, from a single observation on the polari- scope, it is impossible to estimate the percentage of sugar. If, however, the polariscope effect or rotation of the impurities is maintained constant, and the sugar is converted into other sugars (invert

sugar) by the action of acid, the change of rotation is a measure of

the quantity of sugar present. Thus the magnitude of this change

of rotation when pure sugar is used is of fundamental importance

and the A'alue is known as the Clerget constant. The value of the constant which is now in general use throughout the world is 142.66—that is 100—the rotation of sugar, plus 32.66, the rotation

of invert sugar, plus 10, a temperature correction.

During the previous year, the velocity of inversion was determined

and it was found that the time which the sugar was exposed in the

prevailing ^methods to the action of acid was excessive. The data

obtained in this work made it possible to measure, under the proper

conditions of time and temperature, the value of the Clerget constant. The rotation of invert sugar was found to be 33.25, instead of 32.66. This error of nearly 2 per cent affects the value of the total constant by one-half per cent and has appeared in analyses for the past 30

years. The research has also shown that many other sources of error may

be eliminated. These errors are caused by lack of constancy of the

nonsugars. Three general methods of analysis have been proposed

one applicable to all substances, one applicable to beet products which

are free from invert sugar, and one applicable to cane products. The

value of the Clerget constant has been correlated with acid of vary-
REPORT OF DIRECTOR OE BUREAU OF STAITDARDS. 123

ing strengths and with neutral salts formed by neutralization of the

acids.

Solubility of Sugar and the Causes o£ Molasses Formation.

The greatly increased solubility of sugar in the presence of salts results in the formation of molasses, from which no granulated

sugar may be obtained by crystallization. At every stage of the

manufacture the crystallization is affected by the presence of salts. The study of these solubilities is therefore of technical and scientific importance.

During the past year experiments have been made on the relative

effects of sodium and potassium salts in high concentration on the

solubility of sugar. These two metals predominate in the products

of the sugar industry. The results have shown quantitatively the

great influence which the presence of the salts exerts. In continuing the research experiments will be made on the effect of increased temperature and of a great variety of inorganic impurities which occur in beet and cane juices.

Proposed Change in the Normal Sugar Weight.

During the past year a movement has been started by American

sugar chemists to change the normal weight of sugar from the 26

grams, which is now in nearly general use throughout the world, to 20 grams. If this new basis is adopted, the investigation started in

the previous jea.v on the change of rotation of sugar in altered concentrations becomes of pressing importance. Some measurements

have already been made, and, in response to a general request from

sugar analysts, the restandardization is being carried out as rapidly

as possible.

One Hundred-Degree Point of the Saccharimeter Scale.

During the past year the Bureau has been standardizing all sac- charimeters to conform to the new value of the 100-degree sugar point

which was discussed in the previous report. The investigation on

this subject in the Bureau disclosed an error of over one-tenth of a

per cent. Considering the precision with which the modern sac- charimeter is used, this error is relatively a very large one and represents a very large sum of money in the buying and selling of

sugars, as well as in the collection of the revenue on imported sugars. The previously accepted determination of the 100-degree point was made at the Sugar Institute in Berlin.

International agreement on this constant is a matter of great importance, and the Bureau delayed correcting the existing error in

standardizing the saccharimeters and control plates submitted for

test until it seemed almost hopeless to secure such international agreement in the near future. Saccharimeters standardized according to the new value have been giving excellent results and have been

thoroughly satisfactory. Many industrial concerns have sent apparatus to the Bureau to be standardized merely to get their equipment on a correct scientific basis. Tested Supplies for United States Customs Laboratories.

The abnormally heavy importations of sugar and molasses during

the past year have again emphasized the necessity of having reserve

* supplies of all standard apparatus used in the customs laboratories
124 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

available. The situation relative to these supplies has been a most

difficult one, owing to the unusual demands for additional equipment

and owing to the difficulty in securing suitable supplies from the

manufacturers. A customs laboratory is likely to require additional

equipment at any moment. It is not feasible for each laboratory to carry sufficient reserve stock of all supplies that might be needed.

The delay incidental to their purchase and the delivery by the manufacturer and the time necessary to standardize at the Bureau are often

embarrassing. The most logical solution of the difficulty seems to be

a storeroom at the Bureau in which tested supplies for the Customs

Service can be held in reserve and shipped at a few hours' notice, as needed. Preliminary steps have been taken to bring this about.

Customs Laboratory at Boston.

When the construction of a new building for the United States

Appraiser of Merchandise at Boston was authorized, advantage was

taken of the opportunity to provide suitable quarters for the installation of a modern customs laboratorv. The Bureau was called upon

hy the Supervising Architect's office to draw up plans for this

laboratory. It was therefore possible to arrange a distribution of

space which was far superior to what could have been done had the

installation taken place in a building already constructed. Advantage

was taken of the opportunity to make the laboratory a model of its kind, with all new, modern equipment. It has now been in operation

for several months and has proven satisfactory in every respect.

Supervision of Customs Laboratories of the Treasury Department.

For several years the volume of work which the sugar laboratories

of the Customs Service have been called upon to perform has been

steadily increasing. This has occurred in th6 face of continuously

decreasing importations of other commodities. The importations for

domestic consumption during the past year have been the heaviest on record. In addition, Europe has been, to a great extent, supplied

with sugar from Cuba and the West Indies which was purchased under an arrangement whereby it was to be refined in the United States. Since there is no provision in law whereby sugar can be imported into

the United States and refined in bond with the object of exporting

the finished product, it has been necessary to collect revenue on all the raw sugars destined for Europe. It has therefore been necessary

to resort to every possible means in this emergency to increase the

amount of testing done. Fortunately, this desirable result has been

accomplished without perceptible deterioration in the quality of the

work. The percentage accuracj^ of the tests has been successfully

maintained at the prewar basis. Considerable quantities of important new equipment have been

added to the customs laboratories, and the work of assisting the

Treasury Department in improving the personnel and efficiency has

been continued.

Pure Sugars for Miscellaneous Purposes.

The Bureau issues sucrose as a standard sample. Since it furnishes

a source of pure carbon, and since its fuel value is accurately known,

it is widely used as a calorimetric standard in the analysis of coal. It is also used as a saccharimeter standard as a source of pure invert'

sugar for use as a standard in sugar analysis and for other miscel-
KEPOKT OF DIRECTOR OF BUREAU OF STANDARDS. 125

laneous purposes. Dextrose, in highly purified form, is also used as a " reducing " sugar standard in sugar analysis.

Purified dextrose is also used "in bacteriological work in differentiating bacteria. The Bureau supplies it to the Medical Supply Depot for use in this work in the United States Army. Equipment is to be installed at the Bureau capable of handling relatively large

quantities of material, and it will then be possible to supply both

sucrose and dextrose in considerable quantities.

Sugar and Molasses at Southern Ports. The abnormally heavy importations of sugar and molasses through

southern ports were continued during the year. The scarcity of ocean tonnage which became manifest over a year ago has continued,

with the result that the importations appear at the most convenient

port of entry regardless of whether the Customs Service of the

Treasury Department has facilities for collecting the revenue at that

port.

The laboratory which the Bureau has installed at the port of Savannah has been giving excellent results and has relieved the situation to a considerable extent. The Government's inability to equip new laboratories at Galveston and Key West has resulted in still further crowding the already overworked customs laboratory at New

Orleans. It is hoped that it will be possible to relieve this condition

at an early date. Standard Samples.

During the past year 95 standard samples of sucrose and 16 samples of dextrose were distributed. These materials are used principally for industrial and scientific purposes.

Polarimetric Testing.

The Bureau continues to test large numbers of polariscope-tube cover glasses for optical homogeneity. All glasses tested were of

American manufacture. Polariscope tubes, sugar weights, hydrometers, volumetric apparatus, etc., were purchased for the Treasury

Department and tested. Polarimetric Tests of Raw Sugar.

The Bureau has supervision of the sugar testing in the Customs

Service, Treasury Department. In this connection, 1,509 exchange

samples of raw sugar for control purposes were tested. Approximately 50 per cent were direct polariscope determinations of the

quantity of sucrose present, and the remainder were tested for the

percentage of moisture in addition to the sucrose content. Testing of Molasses.

In view of controversies arising between buyer and seller of blackstrap molasses in regard to the quality of the same, the Bureau has

consented to make referee analyses in a number of important cases. Sixty-one such analyses have been made during the past year. Whenever the work will permit, the Bureau will continue to act in this

capacity.

Filtration of Sugar Solutions.

The separation of solids from sugar solutions has become a large

factor in the manufacture of sugar, due to the constant increase in the
126 REPOKT OP DIBECTOE OF BUEEAU OF STANDAEDS.

cost of labor and of the filter cloths. The tendency now is toward

mechanical means which separates the bulk of the solids, thus requiring less to be removed by cloth filters. To aid in the development of

mechanical separation, the Bureau has, in its work on this problem,

so related the various factors which influence mechanical separation

that the behavior of the solid can be predicted over a wide range of

varying conditions.

Beet Molasses.

The middle western beet-sugar factories are troubled with a material appearing in the manufacturing processes which is optically

active and forms solutions of extreme viscosity. The removal of

sugar from solutions containing this unknown material is thereby

rendered difficult. The Bureau has under way the identification and

investigation of manufacturing processes to remove this material.

Color of Sugars and Sirups.

There has been a great deal of confusion in the evaluation of the

color of the various sugar products. The polarimetry and colorimetry sections of the Bureau have investigated and developed a method of exactly defining the value of the color presnt, and a report

will be published on this important subject in the immediate future.

Standardization of Methods of Sugar Manufacture.

The demands upon the Bureau for research work in connection

with the standardization of the processes of manufacture of sugar

have been so insistent that a section devoted to this work has been

established. The work has received the hearty support of the vari- ous manufacturing interests. A number of research problems, in

which the unusual facilities of the Bureau are particvilarly applicable, are now well under way.

Molasses Density.

During the past few years the value of molasses, as Avell as the

quantity consumed, has greatly increased. The determination of

the density of the material has necessarily likewise risen in importance, the value being predicated to a considerable degree upon the

density.

The Bureau has developed a picnometer in the use of which en- trapped air can be removed and the density determined with greater

precision than heretofore.

Definitions and Specifications of Commercial Sugars.

At the present time about 40 varieties of sugar enter into direct

consumption in the United States. A number of these are more or

less similar, but, being made by different concerns, are sold under

different trade names. They range in quality and color from the best

grade of white granulated and cube sugars to the soft, dark-brown

sugar.

It has long been an open question as to whether it would be practicable to prepare specifications and definitions of these sugars which

would make possible their accurate identification. The trade names

give little or no indication of the character of the sugar. During

the year several hundred samples of these sugars have been received

by the Bureau, and a systematic classification is being attempted by
KEPOET OF DIRECTOR OF BUREAU OF STANDARDS. 127

means of chemical analysis, moisture content, color, and numerous

other chemical and physical properties.

The investigation is necessarily an extensive one, requiring much

time for its completion. The results so far secured have been satis- factory. Suitable definitions and specifications now seem possible,

and, if they can be accurately prepared, the result will be a matter

of great importance to both the sugar manufacturer and the general

public.

COLORIMETRY.

(Measurement of the factors determining color ; tlie optical transmissive and reflective properties of materials ; ultra-violet and visual spectrophotometry ; standardization of colorimetric nomenclature ; development of methods and instruments for colorimetry

;

color grading of light sources and materials.)

Colorimetry is the measurement of the physical quantities which

serve to specify color. Color is properly defined as a sensation.

The ordinary stimulus of this sensation is light. Colorimetry, therefore, deals with measurements relating to light. The color of a sub- stance under prescribed conditions is defined as the color produced

by the light reflected or transmitted by it. The color of light is specified by its frequencies (or wave lengths), the relative intensities of

the component frequencies, and their total intensity. The color

white is commonly produced by light of all frequencies between about

400 and 750 vibrations per trillionth of one second (wave length, 750

to 400 millimicrons), in certain relative proportions, as they exist

approximately in daylight. In general, light in which the component frequencies occur in different proportions than these causes a color other than white, and this color may be specified by these

relative intensities and the total intensity. These ratios and intensities are measured by spectrophotometry and photometry, which ai"e thus the basis of colorimetry. There are also various types of

colorimeters by which light of specified frequencies is mixed in

measured proportions to produce a color matching the color being

tested. Color may also be empirically specified by reference to arbitrary colored standards.

The work comprised in this section deals generally %ith light sources, the transparency of materials, and the transmission, reflec- tion, and diffusion of light and other radiant energy by materials.

In some problems where color itself is not the prime consideration,

still the measurements required and instruments and methods used

are identical or similar. Such problems are, therefore, dealt with in

this section. This work is closety related to and interlocks with

other sections of the Bureau's work, viz, photographj'^, photometry,

and radiometry. Its methods find practical application in chemistry,

ceramics, pyrometry, and the testing of textiles, paper, paints, dyes,

oils, and other materials, and in specifications and regulations con- cerning railway and other signals and eye-protective glasses.

Present Status of the Color-Standards Investigation.

For information relative to the nature and scope of the colorstandards investigation, reference is made to the Annual Report of

the Director, Bureau of Standards, 1918, pi. 92. During the year progress has been made on'each section of the work there outlined as the

work which was being undertaken by the Bureau. Particular fea-
128 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

tures of this work will be noted in the following paragraphs. The at- tention given to military inA^estigations and tests during the two years

past has greatly delayed progress on this investigation. On this ac- count the investigation is about one year behind the stage it would

have reached had the war not intervened. This delayed work has

now been actively resumed, and every effort is being made to prose- cute it with all possible speed.

The work now actively in progress or to which immediate atten- tion will be given this year may be classified as follows : Continued

improvement and extension of spectrophotometric methods ; standardization of colorimetric nomenclature ; investigation of "white light

and "average claylight"; application of rotary dispersion to color- imetrey ; investigation of the spectral transmissivit}' of dyes (in co- operation with Bureau of Chemistry) ; investigation of spectral trans- missivity of colored inorganic-salt solutions ; investigation of colored

railwaj^-signal glasses ; development of technologic methods for the

commercial color grading of materials.

Extension and Improvement of Spectrophotometric Methods.

As has been repeatedly emphasized in previous reports, the physical

basis of colorimetry is spectrophotometry and efforts to improve,

systematize, and simplify spectrophotometric methods have been continued. (See Ann. Eep's., 1916, p. 87; 1917, p. 86; 1918, p. 93.)

Definite accomplishments marking progress in this work during the

year may be noted as follows

Visual /Spect7'ophotomet7y.—The improved illumination apparatus

for the Koenig-Martens spectrophotometer, mentioned as under construction in last year's report, has been actually installed and used in

extensive work. This apparatus provides for measurement of both

spectral transmission and diffuse spectral reflection by very small and

quickly made changes in arrangement. Both incandescent and mercury vapor lamps are installed in the apparatus, thus providing for

illumination either by heterogeneous or homogeneous light. It gives a practically perfect photometric field, and is proving altogether very

satisfactory in practice. Further thorough and detailed investigation

of the precision and accuracy of measurement is in progress. A

Bureau of Standards technologic paper describing this apparatus is in course of preparation.

A new spectrophotometer for liquids (oils, dye solutions, etc ) employing the principle of variation of thickness is partty designed.

Measurements already made by this principle Avith an instrument

made in the Bui'eau's shop are very satisfactory, and the method when

perfected promises to afford a great improvement in the measurement

of the transmissivity of liquids. It is planned to use such an instrument in color grading oils and in the investigation of dyes.

Photo-electric /Spectrophotometry.-—The new photo-electric apparatus mentioned in last year's report has been used with great satis- faction in many tests. A brief description of this apparatus has been

published (Jour. Op. Soc. of Am., January-March, 1919) ; and a complete detailed description of it is now in press (Bureau of Standards

scientific paper). Changes are being made by which a thermopile

and galvanometer (thermoelectric method) may be used with the same apparatus. When it is thus amplified the apparatus will enable

accurate measurements to be made over a wave-length range from
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 129

about 380 millimicrons in the ultra-violet, all through the visible to about 1,000 millimicrons in the infra-red.

Photographic Sjyectrophotometry.—The Hilger sector apparatus

has been used in many tests. Minor improvements have been made in

the permanent installation.

Congelation and Comparison of Methods.—Each of the three

methods mentioned above has its strong and weak points. Used

together the}^ serve to supplement each other in a very satisfactory

way, for where one is weak another is strong. For very short wave

length (less than 380 millimicrons, ultra-violet) only the photographic

is used. For wave lengths between 500 and 380, both the photographic

and photo-electric are applicable. The visual method is good between

about 650 and 450, but more or less unsatisfactory bej^ond these limits. In the regions where two or more methods overlap they have been

found to check very satisfactorily in careful work. The thermoelectric method when perfected will complete our requirements by

providing means of measui-ement in the red and near infra-red (wave

length 600 to 1,000 millimicrons).

Temperature Control in Spectral Transmission Measurements.—

The light transmission of a substance is, in general, a function of its temperature. It is therefore necessary to make measurements for accurate work in many cases at a specified temperature, although the

temperature regulation need net be very accurate. Thermostats have

been designed to control the temperature of ihe sample in connection with the Koenig-Martens, the Hilger sector, and the Gibson

photo-electric apparatus. These thermostats are noAv being permanently installed in connection with this apparatus. For the present we are only interested in ordinary temperatures, and these thermostats are therefore designed to operate only at temperatures from

about 10° C. to 50° C. and will usually be used between 15° and 35°. Summary.—The colorimetric section now has working equipment

permanently installed to make spectral transmission and diffuse re- flection measurements on short notice by different methods in a routine way, on a range of wave length from about 220 millimicrons

to about 700 millimicrons, and apparatus for making transmission

measurements at specified temperature is now being installed. Further study of accuracj^ and further efforts for improvement are being

made, and the thermoelectric method will extencl the range to about

1,000 millimicrons.

Development of Technologic Methods for Commercial Color Grading

of Materials.

From a utilitarian point of view, the end and purpose of the color- standards investigation is the development of methods and apparatus

to provide for the routine technical color grading of materials in

which color is a point of interest. This is the reason the industries

urge the Bureau to do the work, and this is, in fact, the reason money

is appropriated for it. Those in active charge of the work know

that this end can only be attained by founding the method on accurate, thorough knowledge of the very recondite and, to the layman,

unfamiliar facts and phenomena involved. They are also, however,

keenly aware of the need of applying this knowledge in a practical

way to the practical problems presented. Time, thought, and effort 1422S9—19 9
130 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

are therefore divided between fundamental research and its application. Below are noted some of the current problems on which

progress has been made and, in some cases, definitive reports issued

during the year. Color Grcoding of Cottonseed Oil.—An investigation of the color

of cottonseed oil has been in progress at the Bureau for a number of

years. An important feature of this work has been the determination of the spectral transmissivities of a large number of representative samples. The Bureau has long been of the opinion that the

simplest, the most definite, and, in the end, the most useful and significant method of color grading this oil would be in terms of its transmissivity for certain selected wave lengths. However, a re- quirement to be met was means for the translation of values on any new scale into approximate values on the Lovibond color scale, which

has been in use in the cottonseed oil industry for perhaps 20 or 30

years. Investigation during the past year has led to the discovery

of a simple relation which makes possible the preparation of such

a conversion table of transmissivity ratios and Lovibond values for

oils near " prime " in color. Recommendations on the color grading

of cottonseed oil which were final and definitive, in so far as fundamental i^rinciples were concei'ned, were submitted to the Convention of Cotton Products Analvsts, by the Bureau's representative.

New Orleans, May 17. 1919. " (Cotton Oil Press, July, 1919, pp.

86-88.) The essential features of these recommendations are as follows

1. Color grading in terms of colored glasses or other material standards should be discontinued except in certain particular cases where

it may be desirable on account of convenience in quick reference or where apparatus for grading by the method proposed below is not

available. The reasons for this recommendation are

(a) Such standards are difficult to obtain and difficult to duplicate.

(&) The calibration and certification of a large number of them

involves an immense amount of labor.

((?) They are of questionable permanency.

{d) The number of them necessary for a complete scale makes

great trouble in practice.

2. The oil should be graded in terms of its transmissivity for

monochromatic light of certain specified wave lengths.

3. Oil nearly " prime " in color should be graded in terms of its transmissivity for 1 decimeter for light of two-wave lengths, viz,

546 millimicrons and 578 millimicrons.

Making use of these measured transmissivities, it will be possible

to express completely and uniquely both the quality (hue and saturation) and the brilliance of the color of the oil. The Bureau will undertake to provide two conversion tables, viz

{a) A table giving values on the Bureau of Standards' average

Lovibond scale in terms of the ratios of the transmissivities for wave

lengths 546 and 578 millimicrons to an accuracy limited only by the

essential uncertainty of the Lovibond scale. (b) A table giving the total transmissivity for average sunlight

(brilliance of oil) in terms of the transmissivity for wave length

578 millimicrons.

The system of grading in terms of transmissivities possesses the

following advantages:
KEPORT OF DIRECTOR OF BUREAU OF STANDARDS. 131

1. It expresses an essential property of the oil itself. It is quite

possible that the chemist in the future will find such data of much

interest aside from its use in specifying color.

2. It is independent of any question of the observer's color vision.

The measurements can be made just as well by a color-blind observer

as by one having normal vision. This is by no means an unimportant

consideration when it is remembered that railroad statistics show that

1 man in 20 is color blind.

3. It is physically simple and capable of precise specification in

easily reproducible units and conditions, thus eliminating arbitrary,

ill-defined, nonreproducible standards.

New apparatus is now being designed to provide for putting these

recommendations into practical elfect, and further cooperative work

on details will be carried out in cooperation with the Society of Cotton Products Analysts.

Color Grading of Pyralin Ivory for Du Pont de Nemours &

Co.—At the request of Du Pont de Nemours & Co., a minor investigation of the color of their product "pyralin ivorj' " has been madeDiffuse spectral reflection curves for a number of samples were made and a report forwarded to the company June 27, 1919.

Color Grading of Sugar Solutions.—Considerable work has been

done on investigation of the spectral transmissivity of sugar solutions for samples from various sources and different concentrations.

This work is in progress, and no reports have as yet been issued.

Attention is being given to the formulation of suitable methods for

routine work, and it appears at present that the solution of this

problem will be comparatively simple.

Color Grading of Various Materials.—The materials which it is desired to grade by color in commerce are almost innumerable, in- cluding paints, dyes, inks, textiles, paper, flour, soap, tobacco, butter,

and many other things. The Bureau's correspondence shows inquiries for information and advice on these problems from the most

varied sources. In practicallj^ dealing with these problems general

principles nearly always have to be specialized, and each problem

requires individual treatment. T^p to the present the Bureau has

been able to give very few of these problems adequate attention.

A method foi- color grading of butter and oleomargarine was

published several j'ears ago (B. S. Tech. Paper No. 92), and since

then this matter has demanded no further attention except in making a few tests in terms of the specification therein given.

Paper grading has been given a great deal of attention in regard

to its transmission, diffuse reflection, and glaze. Previous publications (B. S. Circular No., 63 and Trans. Am. Cer. Soc, vol. 17, Detroit convention, 1915) have dealt with the paper problem in a partial way. Further work has been done and progress made, but this

work has not yet reached the stage for a definite report.

Standardization of Colorimetric Nomenclature.

One of the primary and urgent needs of colorimetry is an established and recognized nomenclature, as well as systems of units,

standards, and symbols. During the year progress has been made

in the formulation and standardization of these matters in the work

of the colorimetric section, but it is necessary that general agreement be reached with all concerned. Action has been taken to bring
132 KEPORT or DIKECTOR OE BTTEEAU OF STAITDAEDS.

this about, the Optical Society of America having formed, in January, 1919, a committee for this purpose with the chief of the Bureau's colorimetric section as chairman. It is expected that this

committee will make a i-eport in December, 1919.

Data on the Spectral Transmission of Various Glasses in the Visible

and Ultra-Violet.

The spectral transmissions of variovis colored glasses are a matter

of great interest in colorimetric and related work, as they may serve

as secondary standards and as " filters " for selecting light of particular colors. There has been need for a compilation of data on

available glasses.

During the last three years the spectral transmissions of a great

number and variety of glasses have been measured throughout the

ultra-violet and visible. These data have now been collected and

a paper on this subject is in course of publication (Bureau of Standards technical paper). The transmissions for the visible and ultra- violet of 87 samples of glass, representing over 50 different kinds,

mostly colored, which are useful for various purposes, are given in

this paper. The glasses listed are representative of what may be obtained to-day on the American market, and include also some of

foreign make which could be obtained before the war. It is thus

possible to make comparison of the relative merits of foreign and

American glass and see in what respects the latter may duplicate or improve upon the former.

All of the glasses listed in this paper, so far as it was i^ossible to get values, were measured photographically and visually and in

most cases photoelectrically. The photographic (Hilger sector photometer with quartz spectrograph) method may be used from 230

to 500 millimicrons, the photoelectric null method from 380 to GOO,

and the visual (Koenig-Martens spectrophotometer) from 436 to 720. The data are presented in the form of transmission curves ex- tending from 720 millimicrons throughout the visible and ultraviolet as far as the specimens have any appreciable transmission.

The methods overlap to such an extent that when all are used ex- tremely reliable curves may be obtained. With possibly a few ex- ceptions, therefore, the curves as given are considered accurate within 0.02 on the transmission scale of 0.00 to 1.00, and in many

cases, especially at low transmissions and in the better specimens,

the uncertainty is definitely less than this. For each specimen are given the transmission curve, the thickness,

the trade name or designation, and the maker or dealer. In each

figure also is given the relative visibility curve for the average human

eye. An inspection of the curves must be made by those interested,

inasmuch as this kind of data can not be summarized.

Various practical uses to which these glasses are put are indicated, such as ultra-violet signaling, railway signaling, improvement of visibility both for visual and photographic work, protection

of the eyes, and selective ray filters. Of special value in scientific Work is their use as filters to obtain monochromatic light from mercury, helium, or hydrogen lamps. Transmission curves of such

filters are given.
EEPOET OF DIRECTOR OP BUREAU OF STANDARDS. 133

Investigation of Railway-Signal Glasses.

As is well known, colored lights are almost universally used on

railways to indicate " danger," " stop," " safety," " clear," " caution,"

etc. It is bv the guidance of such lights that the engineer operates

his train. These colored lights are largely obtained by placing col- ored glasses in front of oil or electric lamps. The standards for

these glasses should be specified in terms of spectral transmission,

and indeed the standards of the Eailway Signal Association are so

specified. It is a matter of prime importance to public safety that

the proper standards be maintained and adhered to rather closely

in practice, which means a certain amount of spectrophotometric

testing. Appreciating this, the Pennsylvania Eailroad. has fre- quently required such tests of this Bureau, and has lately requested

that the Bureau undertake a more extensive and thorough investigation of makers' working standards. It is to be understood that,

while specifications are written in terms of spectral transmission, not every glass to be put to use can or need be tested in these terms. The manufacturers keep certain particular glasses as working standards. Question has been raised as to the authenticity and uniformity

of these working standards, and as the railways themselves are without spectrophotometric equipment, and therefore unable to test the glasses delivered, the question has accordingly been referred to the Bureau. Copies of the makers' working standards have been

obtained and are now in course of investigation. It is expected that

a report will be published within a few months (Bureau of Standards

technical paper).

Investigation of Eye-Protective Glasses.

Many glasses have been recommended and extensively advertised

to absorb injurious radiant energy, and so protect the ej'es when worn

as spectacles or goggles. However, physiologists and oculists desiring to conduct experiments to determine the value of such glasses

have little to guide them in their selections except the claims of

makers and sales agents. In order to experiment or prescribe intelligently, it is obviously necessary tliat authentic and authoritative

data should be available on the spectral transmission of the various

glasses which are being commercially promoted as valuable in protecting the eye from harmful radiant energJ^ Feeling this need of

data. Dr. W. C. Posey, chairman of the committee on hygiene of

the eye, American Medical Association, formally requested this Bureau to make an investigation of the spectral transmission of these

glasses.

The report on this investigation has now been published. (Bureau

of Standards Teclinical Paper No. 119.) In this paper are given the

results on 82 samples of eye-protective glasses which are at present on the American market, the list including various shades of glasses

(5old under the following trade names : Akopos, Amber, Amethyst,

ALrkweld, Blue, Chlorophile, Chromatic Test, Cobalt Blue, Crookes,

Electric Smoke, Euphos, Fieuzal, Hallauer, Luxfel, Noviol, Novitveld, Pfund, Rifleite, Saniweld, Smoke, and others, including heatabsorbing, welding, and colorless crown glasses. Some of these

specimens are of unknown origin, glasses which have been marketed

for years under more or less well-recognized trade names. The

data given show what may be obtained under one of tliese names;
134 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

but, as there are usually so numy different shades of the same kind of

glass Tnai-keted under the single trade name, it can not be expected

that duplicates can be obtained merel}' by ordering by name. However, most of the specimens, especially those of American manufacture, are designated by shade^—that is, " A," " B," etc.—as well as by

trade name or by numbeK and in this case it is expected that approximately duplicate samples can be obtained. Yet in no case, probably,

is the designation a sufficient specification ; but the oculist or buyer,

guided by the data given in this paper, may now prescribe or order

glasses of specified- spectral transmission, acceptance being subject

to test. By means of tables and curves the results of the investigation have

been presented in such a way that the information desired may be

quickl}^ obtainable. For each specimen is given : The trade name (including the shade designation) under which it is marketed; the com- pany from which it may be obtained; the approximate color; the

thickness, the samples being from 1.42 millimeters to 3.20 millimeters

thick, that ordinarily used in spectacle lenses. The per cent trans- mission ciirve from 230 to 710 millimicrons (in each figure there is also given for comparison the transmission curve of a sample of col- orless crown glass and the visibility curve for the average human

eye) ; the total transmission for light of equal energy at all wave

lengths, computed from the visibility curve and the transmission

curve. Precision Determination of Spectral Transmission of Visibility Solution.

A ray filter or screen which transmits energy of different wave

lengths in proportion to its visibility is known as a " visibility filter." A solution of cupric chloride, cobalt-ammonium sulphate, potassium

chromate, and nitric acid in water in a glass cell produces approximately this result. Such filters are necessary in physical photometry.

The spectral transmission of such a filter must be known.

At the request of Dr. H. E. Ives, the spectral transmission of a solu- tion made according to a formula submitted by him has been determined. The solution was prepared by the chemical division at the

Bureau according to the formula submitted: Cupric chloride (Cu CI2. 2H2O), 61.25g.; cobalt-ammonium sulphate (Co SO,. (NHJa SO^.

6H2O), 14.5g. ; potassium chromate (K, Cr OJ, 1.9g. ; nitric acid

(Sp. (rr. at 15°, 1.0.5), 18.0 centimeter; water to total volume of 1 liter. The ratio of the transmission of a 1.03-centimeter glass cell containing

this solution to the transmission of the same cell filled with distilled water was determined with great care by both the visual and photoelectric methods, the total wave-length interval covered being about

440 to 070 millimicrons. A complete detailed report was issued to Dr.

Ives, ISIarch 22, 1919, but has not as yet been published otherwise. It

is expected that publication may be made later in suitable connection.

In the meantime the data may be obtained on application to the

Bureau by any one interested.

Calibration of " Munsell Color Standards."

The Munsell Color System (Wadsworth, Howland & Co., Boston,

Mass., and Munsell Colpr Co., New York) has attained considerable

importance and recognition in art, and particularly in color printing.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 135

This S5'^stein has many good features, but, unfortunately, it was developed and put into practice without adequate fundamental standardization. Lately the Munsell Color Co. has submitted its standards

to the Bureau for calibration. The spectral diffuse-reflection curves

of 24 samples have been determined, and a complete report made to the company. This report has not been published, but the data may

be obtained from the Bureau by anyone interested in it. As one result of the calibration, it appears that the Munsell " value

" numbers are not proportional to diffuse reflection, as seems to be

understood in Munsell's Color Notation, but actually the squares of

these numbers are strictly proportional to diffuse reflection. This

suggests some confusion in the fundamental concepts and basis of the

sj'stem. The diffuse reflections of the Munsell value scale do not form

a geometrical series as in a

" natural " scale of value.

New Radiation Formula.

The energy given out by a complete radiator is a complex function of the wave length and the temperature of the radiator. Many

formulas have previously been proposed to express this complicated

relation. The earlier ones, due to Wien and Ea3'leigh, were long

ago found to be only approximate, not fully representing the actual

experimental facts. A formula representing the experimental ilata much more closely was later devised hj Planck. In working over

the old experimental data in connection with his colorimetric work

a member of the colorimetry section has discovered an empiric rela- tion of a form quite different from that of Planck and representing

the data apparently even better than Planck's formula. The equation or formula representing this relation has been published (Jour.

Op. Soc. of Am., January-March, 1919, and Phy. Eev. (2), 13, 314,

1919) and has proved to be of some interest. Colorimetric and Related Tests,

Twenty-six test reports gi^'ing data on about 90 specimens or pieces

have been issued. The data given were for the most part spectral

transmission in the visible and ultra-violet, but included also reflec- tion measurements, as well as relative spectral-energy distribution in

light sources. Eleven of these reports were on military tests for the

Army, Navj', and National Eesearch Council.

Information Furnished on Color, Colorimetry, and Related Subjects.

Information in response to requests has been furnished on color,

colorimetry, colorimetric apparatus, and related subjects, both by

letter and personal conference with visitors. About 90 such letters of information were sent and about 60 such visitors given oral in- formation.

Military Investigations.

As mentioned above, a great deal of time has been taken from the

work on colorimetry proper to undertake military investigations.

This was mentioned in last year's report ; but at that time it was not

permissible to mention these investigations specifically. The occasion for secrecy now having passed, some account of this work may

properly be given. It was for the most part done in the i^receding

fiscal year, although some of it has extended into the year of this

report-
136 KEPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Ultra-Violet Signaling.

Several months before the entry of the United States into the war the Bureau of Standards was requested to advise the Navy as

to the selection and specification of a lamp to be used as a stern

light so designed that it would be visible to other ships of the same

squadron at 1,000 yards astern, while not visible at greater distances

and not easily picked up by enemy ships.

This request suggested the possibility of screening the source with

a filter transparent to ultra-violet, while opaque to the visible and

observing it with a fluorescent detector. Experiments made at the

Bureau, February to May, 1917, showed in general the feasibility

of this idea, and a letter to this effect was delivered to Admiral R. S.

Griffin, June 1, 1917. A detailed technical report was made to Admiral Griffin, March 6, 1918. A paper on this subject was presented

to the American Physical Society, Washington, April 26, 1919, and

it is expected that an abstract of this paper will be published in the

Phvsical Eeview.

Methods of ultra-violet signaling were also developed independently by others outside of the Bureau about the same time and the

Bureau later assisted these experimenters by performance of tests and loans of apparatus.

Visual Detection of Submarines.

Immediately after tlie entry of the United States into the war the

detection of the submarine was perhaps the most pressing of all war problems. In the course of time various means of detection were developed, some of them highly technical and complicated.

At the outset it appeared that the simplest means of detection—viz,

sighting the submarine or its periscope—should not be neglected,

but developed to its highest possible efficiency. The National Research Council appointed a committee, on which the Bureau of

Standards was represented, to consider and make recommendations on this subject, in particular in regard to aids to vision, methods of

observation, and developinent of the lookout service. The report of this committee (dated July 13, 1917) was prepared

at the Bureau and transmitted to the National Research Council

July 23, 1917. A supplemental report was made October 6, 1917.

Chromatically Concealed Insignia and Detection of Chromatic

Camouflage.

Owing to the fact that different spectral distributions of light

may give the same color, it is possible to have samples accurately

color matched as examined by the unaided eye in daylight, and still show glaring chromatic contrast when examined through suitable

light filters (colored glasses, etc.). This circumstance was a source of danger to the camouflage artist. For example, a fabric might be

dyed green to closely match green foliage, and through a properly

chosen filter it might appear bright reel on a dark green or black

background of normally green foliage. Indeed, it might be about

as conspicuous as a fire at night. On the other hand, it might,

through another filter, appear dark on a bright-red background of

normally green foliage.

At the i-equest of the War Department, the Bureau made several

tests of materials in this respect and was able to recommend dyes

and select fabrics to overcome this difficulty.
KEPOKT OF DIRECTOR OF BUREAU OF STANDARDS. 137

The Bureau did not itself undertake a comprehensive and unified

investigation of the subject of " camouflage." However, a great

deal of work bearing on it was done at the request and instigation

of others working on these subjects. A great deal of oral information on ray filters, spectral transmission, and reflection and chromatic camouflage, often illustrated by experimental demonstration, was given to officers of the Army and Navy and representatives of

the National Eesearch Council. Eay filters were loaned from stock,

and others were made to order of prescribed properties and supplied to the applicants for them.

The Bureau was also asked to investigate the practical possibilities

of chromatically concealed insignia ; that is, insignia woven, painted, or made in such a way that they would be invisible to the unaided

eye in daylight and be rendered visible by examination through

properly selected filters. Many combinations of dyed fabrics were

prepared which were nearly or quite indistinguishable to the unaided

eye, but showed remarkable color differences when examined through

suitable filters. These were exhibited and explained to numerous

representatives of the War and Navy Departments. An exhibit of some of these was made in connection with the American Physical

Society exhibit at the Bureau, April 25-26, 1919. Publications.

Numerous reports were issued. Some of them were of no interest

except in the particular circumstances of the test at the time. Those

which may be of some permanent interest are listed below

:

1. Letter to General Engineer Depot on Visibility of Green Tape;

May 17, 1918.

2. Visual and Photographic Tests of the Visibility of Green Tape,

submitted by General Engineer Depot, Bureau of Standards test No.

23667; June, 1918.

3. Visual and Photographic Tests on the Visibility of Green Tape,

submitted by Office of" Quartermaster General, Bureau of Standards

test No. 23978 ; August 12, 1918.

4. A Green Cotton Dye to Simulate Green Foliage ; November 12,

1918.

5. Spectral Transmission of Eight Aviator Goggles from England,

submitted by National Eesearch Council (subsequently identified as

" Brock goggles ") ; June 13, 1918.

6. Spectral Transmission of Screen Prepared by C. E. K. Mees to Duplicate Brock No. 61, submitted by science and research division,

Bureau of Standards test No. 24034; August 23, 1918.

7. Optical Duplication of Light Filter Known as " Brock No. 61

"

;

September 9, 1918.

8. Duplication of Light Filter Known as " Brock No. 61 " (supplement to Eeport of September 9) ; September 30, 1918.

9. Spectral Transmission of Two Pairs of Anticamouflage Goggles, submitted by Navy Department, Bureau of Standards test No.

23662 ; June 22, 1918.

10. Dichromatic Eed-blue Screens Prepared by Bureau of Standards for Navy Department; supplement to Bureau of Standards

test No. 23662 ; July 9, 1918.

11. Letter to Bureau of Construction and Eepair, Navy, Describing Preparation of Dichromatic Filter Made to Order to Duplicate

Prescribed Spectral Transmission; October 9, 1918.
138 KEPOET OF DIRECTOE OF BUEEAU OF STANDARDS.

12. Diffuse Eeflecting Powers of 13 Samples of Painted Canvas,

submitted by development branch, photographic section. Bureau of

Aircraft Production, Bureau of Standards test 23880; August 30,

1918.

Optical and Photographic Methods for the Detection of Invisible

Writing.

Early in the Avar it was suspected with more or less plausibility

that German agents were using so-called "invisible inks" in their

communications. The secret service agents of the Government had

intercepted and held on suspicion vast quantities of correspondence,

and the Bureau of Standards was asked for advice as to methods

of examining this for the suspected invisible inscriptions, which,

if existent, could doubtless be developed and read by suitable means. Development and supervision of chemical tests was assumed by other

agencies, and this Bureau undertook only the matter of optical

and photographic tests. Special apparatus was designed and con- structed at the Bureau and used by the offices of the Naval and Military Intelligence. The purpose of this apparatus was to provide

convenient and rapid means for the routine examination of a great

number of pieces. The methods for regular routine examination were the following: (a) Examination in intense light at grazing

incidence; (b) examination by regular reflection; (c) examination by

transmitted light; (d) examination in extreme violet and ultra-violet

light; (e) examination by ultra-violet photographj^

The first three tests mentioned above involve essentially nothing more than specific control of the direction of illumination and the

line of sight in the examination of the paper. It is a matter of

common observation that faint marks, erasures, indentations, etc., on a sheet of paper can be seen much better at certain angles than

at others. The apparatus for tests (a) and (&) merely provides

convenient and comfortable means for the critical examination under

two specific conditions, both of which greatly accentuate the appearance of irregularities in the paper surface. For test (c) the paper was laid on a ground glass illuminated from below. No special

apparatus needed to be constructed, as an Edison mimeoscope served

this purpose very well. Methods (d) and (e) are somewhat further removed from ordinary experience, and so require more explanation.

Method (d) depends upon fluorescence; that is, the property which

many substances possess of emitting light when excited by ultraviolet rays which themsL-lves do not cause vision.

Inscriptions made with such substances, dissolved and used as inks,

may be quite invisible in ordinary light under any kind of illumination, but show up in bright characters on the darker background of

the paper when excited by ultra-violet rays. Paper itself, in com- mon with many materials, is fluorescent in varying degree. If the

ink is comiDosed of a substance less fluorescent than the paper, or if the solvent dissolves the surface glaze, the writing will show dark on a light background. Inscriptions written with pure water may

be detected in this manner on some kinds of paper.

The test is performed by allowing ultra-violet rays to fall on the

paper in a dark room. The ultra-violet is obtained from a CooperHewitt glass mercury lamp screened by a glass which absorbs nearly
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 139

all of the light from this lamp while it transmits very freely the

ultra-violet and a small amount of violet light.

Method (e) depends upon the fact that some substances may be

so nearly the color of white paper as to produce little or no contrast when inscribed on it, while the}' may differ from it sufficiently in

their absorption for ultra -Adolet as to give noticeable contrast in an

ultra-violet photograph. For this purpose ultra-violet rays of wave

length considerably shorter than used in the fluorescence test were

employed. The quartz-mercury^ arc and the iron arc are suitable sources for such rays. The blue and violet light and the longer wave

length ultra-violet are absorbed by an aqueous solution of nickel

sulphate and gaseous chlorine in quartz cells. Since these rays are absorbed by glass, the lenses used must be made of quartz, fluorite, or other material which will transmit them.

Five illustrated technical reports on this subject were issued to the

Office of Naval Intelligence during the war. Information on this

subject was also given to the division of Military Intelligence. An

exhibit of the apparatus used was included in the American Phy'sical

Society exhibit at the Bureau ; April 25-26, 1919.

The methods developed are also of use generally in the critical examination of paper and documents. Last April the Bureau was

able to decipher the name and address on a military-registration

card sufficiently well to establish certain identification of the bearer

after the card had been immersed in sea water with the dead body

of the drowned registrant so long that it was quite illegible to ordinary observation and the body itself was completely unrecognizable.

A Method for Color Grading of Red Signal Flares.

At the request of the American University Experiment Station, a method for color grading red signal flares was developed and a re- port issued in July, 1918. This method had also been described in a communication to the American Physical Society and is now in course of publication (Phy. Rev.).

Searchlight Investigation.

The high-power search lamps have acquired tremendous importance in the last few years. Few data, however, are on record regarding some of the fundamental characteristics of these search lamps or bearing upon some of the fundamental problems under searchlight

illumination. An investigation in cooperation with the Corps of

Engineers of the Army has been carried on, using the combined

facilities of the coloriinetry section of the optics division and the

photometry section of the electrical division at the Bureau. This

work is briefly' described below.

From data collected by the Bureau, two distinct types of distribution appear : That in the medium intensity arcs resembles a " rose

" distribution ; that in the high intensity a " cardioid " distribution.

The development of high-intensity arcs by the use of specially pre- pared carbons has resulted in the production of a light which is very

blue relative to artificial inca)idescent sources. In a general investigation of searchlights, including the effectiveness ancl suitability of

their illumination for various purposes, it appeared desirable to have

at least approximate quantitative data on the color of this light.
140 KEPOKT OF DIRECTOR OF BUREAU OF STANDARDS.

An investigation was made by spectrophotometric and special

colorimetric methods and a report was issued to the Corps of Engineers and others January 23, 1919. Another report was made to the

American Physical Society April 25, 1919, and will be published in

the Physical Review.

The result of these investigations may be roughly summarized by

saj'ing that the color of the light from these arcs is approximately

equivalent to the light of the noon sun at Washington, although

relatively more intense in the blue-violet.

The diffusion or scattering of light along the path of a searchlight

beam is very important from several standpoints. The diffusion of

the light out of the beam decreases the intensity of light falling upon

the target. This diffused light lunits the visibility of the target for an observer near the search lamp who must look through and along

the beam. On the other hand, this diffusion of the light along the

beam makes possible the use of the searchlights as landmarks for

military and other jDurposes ; and also facilitates the training of the

beam in a given direction, particularly when combined action of two

or more search lamps is desired.

Measurements have been made from various directions of the

brightness of the path of the beam due to the diffusion of the light

by the atmosphere. The per cent of polarized light in the diffused

light has also been determined.

In order to make any conclusions as to the size and distance of a given target that may be seen in a searchlight beam, there is demanded some knowledge as to what is the minimum difference of

brightness that the eye can detect. Laboratorj^ experiments were made to collect data upon the contrast sensibility of the eye under

conditions closely simulating those under actual searchlight illumination. Very definite results have been obtained.

In connection with the testing and use of search lamps the ques- tion of how much light is lost as the beam penetrates the atmosphere

must be considered. It is important to know what the transmission

of the atmosphere is when tests are made at great distance from the

search lamp.

Very meager definite data exist upon the transmission of the at- mosphere under all weather conditions—clear, hazy, foggy, rainy, etc. It is important also to have a knowledge of the relative transmission for different-colored lights.

A method has been devised to procure relative data on the trans- mission of the atmosphere throughout the spectrum, and some observations have been made for a clear atmosphere, for one of rather

high humidity, and for rains. Other kinds of weather could not be

taken advantage of thus far. It is planned, however, to continue

these observations for foggy weather.

These data are not only valuable for the searchlight engineer, but

are important also in aerial and other photography and to the illuminating engineer interested in automobile head lamps, etc. A chart has been made showing where all losses of light in the

search lamp take place, and their magnitude from the moment the current flows through the arc to the time that the beam impinges

upon the target.

A physical photometer is under construction for use in connection

with the photometry of search-lamp arcs. On account of the high
EEPOKT 0]? DIKECTOE OF BUREAU OF STANDAKDS. 141

intensity of the light from arcs they are admirably adapted for the

application of the physical photometer.

OPTICAL INSTRUMENTS.

(Design of optical instruments ; testing and research on optical systems, optical instru- ments, and appliances such as telescopes, binoculars, cameras, gun sights, and the like, and optical parts such as lenses, prisms, mirrors, parallel plates, etc.)

Effect of Striae on Optical Glass.

An extended investigation has been conducted on the subject of

striae in optical glass and their effect on the performance of the completed optical instrument. Numerous photographs have been taken

showing the degree of striation in the glass and the corresponding

effect upon the definition of instruments in which the striated glass

has been used. The results of the investigation made on the subject

of striae are being prepared for publication. Though difficult to give

any but a photographic measure of the amount of the stria?, it may be

said in general that striae, if faint or few in number, are not very in- jurious in the objectives of binoculars, but considerably more so in

the prisms and oculars.

Refractometer Design.

The two standard types of refractometer, an instrument for measuring refractive indices, are known as the Abbe and Pulfrich. Until

recently all such instruments were made in Germany. Their Abbe

type was accurate to five units in the fourth decimal place, while the

Pulfrich was accurate to one or two units in the fourth. Since the

beginning of the war other countries have entered the field and some

little effort has also been made to develop American instruments of

these two types, which would be more accurate than those of foreign

manufacture.

A design for an improved type of Pulfrich refractometer, in wliich

the scale is horizontal instead of vertical, as in the old type, has been

worked out in the Bureau. The error of this instrument should be

less than that of the German instrument, not greater than two units

in the fifth decimal place, as compared with, say, one or two in the

fourth for the German instrument.

An Abbe type of refractometer has been designed recently by an American manufacturer with the aid and advice of the Bureau. The

Bureau made a careful examination of the preliminary model and

recommended several changes. The final instrument, when actually

tested, was found to be accurate to five units in the fifth decimal

place, making it the most accurate of this type which the Bureau has

tested. Circular Letter on Methods of Silvering Glass.

In response to numerous requests for information on the subject

of silvering glass, a circular letter of information was prepared in

which all the standard methods were collected and put into convenient

form.

Camera for Photographing the Inside of a Machine-Gun Barrel.

The Machine-Gun and Small-Arms Section of the Engineering Di^dsion of the Army has been studying the deterioration of the inside of

machine-gun barrels due to the action of the hot powder gases. Their

practice has been to fire a few thousand rounds and then saw the barrel
142 KEPORT OP DIRECTOR OF BUREAU OF STANDARDS.

lengthwise. Being desirous of studying, however, the successive

stages of deterioration, they requested the Bureau to devise means

for examining the interior of the barrel without impairing the useful- ness of the firearm. A special camera has, therefore, been designed

to permit the taldng of a panoramic photograph of the inside of the

barrel. It is now being constructed in one of the Bureau's shops.

Night-Firing Device.

A small projection device for throwing a spot of light on a plotting board for use in connection with night firing was designed for

the Ordnance Department of the Army. Two of these devices were

built for this Department in the shops of the Bureau.

Condenser System.

At the request of the Medical Service of the Army, a suitable set of condenser lenses to be used with an acetjdene flame for microscopic

work in the field was completed axid submitted to the Medical Supply Depot.

Calculation and Removal of Certain Errors in Centered Systems of

Lenses. • In designing and in testing a system of lenses—e. g., for a tele- scope or camera—the refined calculations by trigonometric functions

are not necessar}- for the treatment of errors of the lower orders.

Those errors can be computed to first and second approximations by

algebraical formulas. For this purpose tables have been devised.

One set of tables with graphs to expediate a preliminary' survey, has

been computed and put in use—the table for eliminating spherical

aberration. By means of this it is estimated that results can be obtained in one-tenth the time formerly needed. A paper soon to be

pulilished describes this work in detail. For eliminating astigmatism a table is partly finished which will

simplify the woi'k. It is so devised that the two errors—^those of

spherical aberrations and of obliquity—are computed together^ giving the position and curvature of both astigmatic image surfaces.

Chromatic aberration is, in practice, removed in advance of these

other two errors by projDer choice of focal lengths.

Testing of Optical Systems.

The Bureau was called upon to make various tests on a wide

A'ariety of optical instruments. Periscopes, small range finders, gun

sights for both Army and Navy, bombing sights, in addition to the more common types of instruments, were brought to the Bureau for

both test and advice. In some cases the work done has been comprehensive; in others the assistance rendered consisted simply in a short

conference in which certain details of the instrument were discussed

and insi^ected. (a) Tank sight.—The Bureau cooperated with the Inspection Division of the Ordnance Department of the Army in the development of

a tank sight. Both the consulting and the laboratory facilities of the

Bureau were used freely for putting the instrument on a production

basis. The range scale for it was computed at the Bureau and a rep- resentative of the optical instrument section made a special trip to Boston in connection with the production of the instrument.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 143

(h) Gun sight.—The Bureau cooperated to a considerable extent with the Inspection Division of the Ordnance Department in the

development and testing of 37-millimeter gun sights.

(c) Machine-gun panoramic sight.—A conference on the specification for the panoramic sight for machine guns was held at the Bureau on July 15, and from then on up to the time of the signing of

the armistice the Engineering Division was in frequent consultation

with the Bureau with reference to the specifications and performance

of this instrument.

{cl) Periscofic alidade.—A French periscopic alidade was sent from the Expeditionary Forces to the General Engineer Depot with

the request that the instrument be copied and supplied to the American forces. The instrument was turned over to the Bureau, where

its component parts Avere carefully measured and drawings necessary

for the construction of a similar instrument furnished the Engineer

depot. From these the Central Scientific Co., an American firm,

made a sample instrument, which was returned to the B.ureau for in- spection. This instrument, after a few minor changes, was approved.

Binoculars.

A large portion of the activities of the optical-instrument section was centered upon the testing of binoculars. The Bureau was re- quested to perform check inspections on one out of every hundred

binoculars produced for the United States Army. Special apparatias was desigiied and built for the rapid testing of these instruments.

This testing apparatus was adopted by the Signal Corps, who borrowed a member of the Bureau staff to take charge of the Signal

Corps inspectors and Bureau methods of testing at the various factories. A school for the instruction of inspectors of binoculars,

lasting three weeks, was held at the Bureau during October. This was attended by 10 Signal Corps' inspectors, who were, after receiving their training, sent out to the various factories to perform ac- ceptance tests on binoculars.

A manufacturing company undertook the manufacture of binoculars for the Signal Corps. The}^ had considerable difficulty at first in getting the optical parts of the binoculars properly placed in the

instrument and referred some of their troubles to the Bureau, which was able to be of assistance in getting this company on a production

basis. In consultation with the Bureau of Standards another company

embarked on the manufacture of a new type of binocular in which

the machine work is largely replaced by pressed metal parts. This

company has produced a very promising binocular. Tests extending over a period of three months were made on the

lenses of six Army field glasses for the purpose of determining the

rate of growth and development of blisters in the cementing com- pound of the lenses. In general, it was concluded that lenses with

bubbles or blisters in the cement should not be used in an instrument

because of the probability of the defects increasing in size, and, furthermore, that the final inspection of lenses should not take place sooner than two weeks after they have been cemented.

The United States Shipping Board, Emergency Fleet Corporation,

gave orders for 1,000 binoculars to be used on board the merchant

marine, and requested the Bureau to perform acceptance tests on
144 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

each instrument. Something over 1,600 binoculars were tested in

order to secure the 1,000 acceptable instruments. The two main

causes of rejections were lack of parallelism of the two barrels and

failure of the two barrels to be simultaneously in focus. At first the

rejected instruments were returned to the factory for readjustment,

but later on the need for these instruments became so great that the

rejected instruments were adjusted in the Bureau laboratory and

immediately forwarded to the Shipping Board.

Determining Constants of Optical Glass.

All the melts of optical glass made at the Pittsburgh laboratory

of the Bureau, about 300 in number, have been submitted in samples

to the opticahinstruments section for the determination of the re- fractive indices, dispersions, and transmission factors. The refractive indices and dispersions were at first determined on a spectrometer. This method involved the expense and delay

incident to the making of a small and* accurately finished prism of

each kind of glass. Subsequently a Pulfrich refractometer, which

requires only a small slip of glass about 2 by 10 by 20 millimeters in

size, polished on one face and one end, was substituted for the spec- trometer and the measurements thereby greatl}' facilitated. A Martens polarization photometer served for measuring the transmission.

In addition to testing Bureau of Standards melts, measurements

of the same sort for a number of other manufacturers of optical

glass were made, as also the customary index determinations of other

substances.

Tests of Instruments.

Following is a list of tests made by the Optical Instruments Section : Binoculars. For Signal Corps For Naval Ordnance Bureau

For Shippins Board (acceptance tests) For private individuals

Military telescopes

Navy sighting telescopes

Gun-sight telescopes . Telescopic sights

Tank sights

Machine-gun panoramic sights Bore sights

Aiming circles Range finders Trench periscopes

Periscopic alidades Azimuth telescopes

Telescopic clinometers Sextants Lens systems.

Photographic lenses: Complete tests Focal lengths

Radii of curvature Other lenses

Focal lengths , Radii and constants Centering

1, 105

13 851

5

210

2

12

54

14

G

3

22

1

1127

18

76

22

72

>,034

54

226
EEPOKT OF DIRECTOR OF BUREAU OF STANDARDS. 145

Optical glass.

Indices of refraction and dispersion constants Transmission factors Indices and dispersions of substances otlier tlian glass.

218

191

27 436

Miscellaneous. Lens test plates, radii of curvature. Refractometers

Parabolic mirrors

Goggles

28

4

4

75 111

Total 2, 861 RADIOMETRY.

(Development of standard instruments and methods of measuring thermal radiation, commonly designated ultra-violet, visible, and infra-red rays ; determination of the re- flective, absorptive, and emissive properties of materials for thermal radiation ; develop- ment of standards of thermal radiations ; determination of radiation constants ; and the measurement of thermal radiation in absolute value.) Radiometry.

Investigations in the general subject of radiometry were greatly

interrupted by military work. Kesearch work on the improvement

of radiometric devices was carried on with the view of making a

practical application in signaling by means of thermal radiations.

As a result the investigation of the radiation constants, upon which

progress was mentioned in previous reports, has been in abeyance.

A study of the data published by Kahanowicz indicates that if a

correction is made for atmospheric absorption the value of the coeffi- cient of total radiation (Stefan-Boltzmann constant) obtained by that

experimenter is in close agreement with the value S=5.72X10"^^ watt,

cm~^ deg"*, recently obtained in this Bureau.

A further examination was made of the accuracy of the factors

used in converting the prismatic spectral-energy curve into the nor- mal-energy distribution. Graphical methods Avere employed; also

computational methods using the first differential of the dispersion

formula which best represents the observed refractive indices of

fluorite. Owing to incompleteness of the formula, the graphical

method is just as accurate as is the method of direct computation.

The conclusion arrived at is that the spectral-radiation constant, C=14353 micron deg., determined some years ago, remains

unchanged.

Among the minor investigations was a determination of the utility

of ribbed and hammered glass, as compared with plane glass, in

greenhouses. The conclusion arrived at is that, aside from preventing direct sunlight from striking the plants, there appears to be no

particular advantage in using a special glass in greenhouses.

Some Optical and Photoelectric Properties of Molybdenite.

A thorough investigation was made of some of the optical and

photoelectric properties of the sulphide of molybdenum, molybdenite. The transmissive, reflective, and polarizing properties were

determined.

Extensive data were obtained on the spectral photoelectric sensitivity of molybdenite as affected by temperature, intensity of the

142289—19-—10
146 KEPOKT OP DIRECTOR OF BUREAU OF STANDARDS.

energy stimulus, humidity, etc. This substance is unique in having

three well-defined bands of photoelectrical sensitivity. Moreovei',

the positions of these maxima, when plotted in terms of frequency

instead of wave length, are separated by equal intervals. This phe- nomenon does not appear to have been observed heretofore and will

form the basis of a new line of investigation in photoelectric phenoraena. An important application of these data was made in signaling by means of infra-red rays, as described in a subsequent paragraph.

Spectral Photoelectric Sensitivity of Silver Sulphide and Other Substances. In _ connection with the development of radiometric instruments

for signaling by means of invisible radiations, an investigation was made of the spectral photoelectric properties of various substances.

New and imj^ortant data were obtained on the spectral photoelectric^ sensitivity of the sulphides of bismuth and silver. The minerals

pyrite, cylindrite, jamesonite, and galena did not show photoelectrical sensitivity for the highest spectral-radiation intensities available.

The effect of temperature, of intensity of the exciting light, and of

mechanical working upon the photoelectrical sensitivity of silver

sulphide was investigated.

_ At room temperature the photoelectrical sensitivity of crystalline

silver sulphide, acanthite, is affected by a polarization phenomenon'

which disappears at low temperatures. The investigation of these

materials has provided new data, the importance and the application of which will no doubt become more apparent as our knowledge

of these phenomena is increased. As matters now stand, there is no

satisfactory explanation of the cause of photoelectrical sensitivity in

substances, and further investigation is highly desirable.

Thermal Radiophonic Signaling Devices.

In the transmission of intelligence by means of invisible thermal

radiations radiometry attained one of its greatest triumphs and one

of its most far-reaching applications.

The unusually high photoelectrical sensitivity, as well as the

quickness of response, of molybdenite, for infra-red rays renders this

substance far superior to selenium as a radiophonic signalinn; device.

Successful field tests were made, using simply a receiver of molybdenite, which was connected through a dry battery to the input side

of an audion amplifier. The source of radiation was a small tungsten

lamp in an automobile headlight reflector. A rotating sector interrupted the light incident upon the molybdenite and produced a pulsating current, which was amplified, thus producing a loud musical

sound in the telephone receiver. Tests were made also using the light

of the moon as a source of infra-red radiation. Loud signals could

be produced with infra-red lunar radiations having an energy value

of only 3x10"^ gr- cal. per second.

Ultra-Violet Signaling.

The rotating sectored-wheel device for producing a pulsating cur- rent in a photoelectric substance, and hence an audible sound in the

telephone receiver of a radiophonic signaling device, is inefficient. Apparatus was devised which utilized all the incident radiation, as well as a long exposure of the receiver, which is not possible with a
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 147

sectored wheel. The signal was recognized by a change in jDitch of

the sound in the telephone receiver, which was used with an audion

bulb. It was found that the molybdenite receiver is not as efficient as is a photoelectric cell of the gas-ionic type (e. g., the potassiumhydride photoelectric cell) , which happens to be sensitive only to the

ultra-violet and visible rays, but which appears to be especially

adapted to this method of signaling.

Reflecting Power of Stellite and Lacquered Silver.

Stellite has reflective qualities which are promising. The sample

examined was more homogeneous and had a higher reflectivity in the

visible spectrum than the samples previously reported upon.

In connection with the question of finding a substitute for the glass

reflector used in searchlights and other apparatus (which problem was

submitted by the War Department), an examination was made of the

effect of ultra-violet light upon lacquered silver. It was found that

the lacquer undergoes photochemical action which affects the silver

and decreases its reflecting power.

Protection of Moving-Picture Film from Heat of Lamp.

In certain work it is desired to stop the movement of the picture

film in order to make an examination of the details of a single picture

projected upon a screen. As ordinarily used the moving-picture film is partly protected

from injury by the intense infra-red rsijs from the lamp, because it is exposed to these rays for only an instant. Applying the information obtained in a previous investigation, the intensity of the infrared rays was greatly reduced by using a dilute solution of cupric

chloride which absorbs but little of the visible spectrum, but which

is practically opaque to infra-red rays. Exclusion of Ultra-Violet Light from Buildings.

The problem was presented bv the War Department to find a substitute for colored glass to exclude the ultra-violet solar rays from

balloon hangars and from other buildings requirinj? such protection. Tests were made showing that varnishinq; plain glass with

dilute asphaltum varnish is very efficient in absorbing the ultra-violet

rays. A better method is to provide a sort of Venetian blind, or

louver of wide slats, painted buff to reflect the light into the building.

Information Furnished on Radiometric Subjects—Conferences.

Information was given on various radiometric matters, such as, for _ example, photoelectric substances ; reflectivity data ; eye protective glasses; methods of making radiant-power life tests of mercury-vapor lamps; ultra-violet radiations used in life tests of fabrics;

substitutes for expensive colored glass in balloon hangars; thermal

radipdynamic devices for signaling; radiometric methods of detecting: invisible hot objects; demonstration before a special naval board

of this Bureau's thermal radiodynamic signaling apparatus.

Publications on Radiometry.

The following publications on radiometry were issued during the

past year

:

Technologic Paper No. 93 (third edition, revised and enlarged) ; Glasses for Protecting the Eyes from Injurious Eacliations; Scien-
148 EEPOKT OF DIRECTOR OF BUREAU OF STANDARDS.

tific Paper No. 325, Spectroradiometric Investigation of tlie Transmission of Various Substances; Scientific Paper No. 330, The Decrease in Ultra-Violet and Total Radiation with Usage of QuartzMercury Vapor Lamps ; Scientific Paper No. 338, Some Optical and

Photoelectrical Properties of Molybdenite (in press) ; Technologic

Paper No. 128, Effect of Solar Radiation Upon Balloons.

INTERFEROMETRY.

(The light wave used as a fundamontal standard of length ; variation of this standard

lentcth with the medium throufjh wliich it passes ; measurement of very small displace- ments ; general development of interferometry.

Thermal Expansion of Small Samples.

The expansion of small samples due to temperature changes is most accurately determined by methods that make use of the interference of light waves. A scientific paper describing the apparatus

and method with which the expansion of a single pin, 10 millimeters

long and .5 square millimeters in cross section, can be determined

is ready for publication. The description of the apparatus and

method for determining the expansion of three different samples

simultaneously was published in the Journal of the Washington

Academy of Science, May 19, 1919. Suitable temperature-control

apparatus has been installed, so that expansion determination can

be made with the temperature range —190° to 1,000° C. During

the past year the thermal expansions of 85 samples of optical glass were measured over the temperature range 20 to 650° C. Several

tests were made for different glass manufacturers. Other materials,

such as invar, steels from which precision gauges are made, human

teeth, and dental porcelains and amalgams, were investigated.

Dimensional Changes of Dental Materials.

In connection with the Bureau's investigation of dental material,

which was undertaken at the request of the Surgeon General's office, interference methods were employed to make measurements of di- mensional changes of the materials. Changes of dimension usually

takes place in porcelain and amalgam used in filling teeth for some

time after they are made up. Measurements of these changes, com- mencing a few jninutes after the material was prepared and extending over a period of from one to four days, were made on 90 samples.

In order to determine the effect of temperature changes on fillings,

the thermal expansions of teeth and different kinds of materials were investigated. It was found that the expansivity of the amalgams was about four times that of the teeth, while for porcelain it was about the same. The results of this investigation are ready for

publication.

Standardization of Precision Gauges.

Precision end gauges, which are steel blocks with two opposite

faces plane, parallel, and a specified distance apart, are used as master gauges for precise mechanical work. These gauges are made

so nearly perfect that it is impossible to determine their errors with

any contact micrometric apparatus. Interference apparatus and

methods have therefore been employed in the calibration of these

gauges. During the past year several sets of gauges were calibrated

relative to the standard light waves and a large nimiber.of other
BEPORT OF DIRECTOR OF BUREAU OF STANDARDS. 149

gauo-es were compared with the secondary standards. Seven thousand six hundi-ed gauges manufactured at the Bureau and 3,-500 from manufacturing companies were tested. Change in dimension

with age and change in thermal expansivity, with the composition

and heat treatm.ent of the steel used, were found to be important

factors in the reliability of precision gauges.

DISPERSOIDS.

(Investieation of tbe physical properties of dispersoids. such as smokes, water supplies,

biolosical fluids, gelatin films, etc. ; preparation and specification of standard dispersoids ; development and standardization of dispersoid constants, instruments, and methods of measurement ; cooperation in the technical apiJlication of dispersoid information in other branches of Government, in science, and in the industries.) Properties of Smoke.

The word " smoke " denotes the products of combustion forming

a visible cloud of small particles. These may be either solid, as the

carbon particles from a sooty flame, or liquid, as the vegetable-oil

particles in tobacco smoke. Smokes are of military importance for

screening purposes, and the attention of the French Commission,

during their visit to the Bureau, was called to its great utility at the

front. During the war the Bureau was asked to cooperate with the

Chemical Warfare Service in investigating the properties of toxic

smokes. To do this most quickly and thoroughly the Bureau specialist worked with the research division of the Chemical Warfare

Service. For the work of the gas-mask research section it was

necessary to design a sensitive photometer for measuring the smokes

which could be produced in this country. Two of these instruments,

built by the American Standard Motion Picture Co., were completed

when the armistice was signed. Some parts of the joint investigations with the dispersoid section of the service were published in

the Journal of the American Chemical Society, volume 41, pages

312-329.

5. CHEMISTRY.

[Chemical composition and purity of material; chemical properties and constants, including

researches upon methods of analvsis. specifications for technical rraterials, and prepa-ation

of pure materials for standardization work for the Government and for industrial and

scientific laboratories.] Chemical Testing.

The number (18,436) of chemical tests made in the chemical

labox-atories during the year slightly exceeded that of the pi'eceding

year. Distributed by types of materials, they were as follows: Ferrous metals (irons and steels), 1,177; nonferrous metals, alloys, and

coated metals, 980 ; cement and cement materials, 8,091 ; bituminous

products (including creosotes, etc.), 1,129; A^arnish materials (including shellacs), 839; paint materials, 1.016; lubricants, 557 ; soaps, nondrying oils, and metal polishes, 674; inks and related office supplies. 673; balloon fabrics, 840; rubber, 906: leather, 421; textile^. 745: miscellaneous, 408. The tests were made foi' very manv Government bureaus and

establishments and for States, municipalities, and private parties, as follows : Agriculture, 102 ; Commerce, 10,057 : Navy, 737 ; Post Office. 474: Treasury, 525; War, 4,409; Panama Canal, 1.171; General

Supply Committee of the District of Columbia, 533 ; U. S. Shipping
150 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Board, 148 ; othei^ Federal institutions, commissions, and committees,

220 ; State, municipal, and other institutions, 34 ; private parties, 26. Chemical PubHcations.

The following papers emanating wholly or in part frem the chemistry division were published during the j^ear or are nearly ready for

jmblication

Zinc-Cyanide Plating Solutions, published in Monthly Review American Electroplatei-s' Society, volume 5, Nos. 11 and 12, and volume 6, No. 4, 1918. Military Applications of Electroplaitug, published in Metal Industry, volume

16, page 49S, 1918. Notes on Black-Nickel Plating Solutions, to appear in Monthly Review American Electroplaters' Society.

Operation of Fluoborate Lead-Plating Baths, to appear in Review American

Electroplaters' Society.

Lead Plating fi-om Fluoborate Solutions, to appear in Transactions American

Electrochemical Society. Factors Governing the Structure of Electrodeposited Metals, to appear in Transactions American Electrochemical Society.

Report on Ladle Test Ingot Investigations, to be published as an appendix

to the report of committee A-1, American Society for Testing Materials, 1919. Electrolytic Resistance Method for Determining Carbon in Steel, to be published in .lournal of Industrial and Engineering Chemistry.

Technologic Paper No. 1]8. Critical Study of the Ledebur Method for Deter- mining Oxygen in Iron and Steel. Technologic Paper No. 126, A Study of the Goutal Method for Determining

Carbon Monoxide and Carbon Dioxide in Steels. Scientitic Paper No. 346. Oxygen Content by the Ledebur Method of Acid Bessemer Steels Deoxidized in Various Ways.

Scientific Paper No. 350, Equilibrium Conditions in the System Iron Oxide,

Carbon, aud Hydrogen in Relation to the Ledebur Method for Determining

Oxygen in Steel. Technologic Paper No. —, Investigations at the Bureau of Standards on Gases

in Steel and on Deoxidation of Steel, also to appear in Bulletin Institute of Mining Engineers.

The Generation of Hydrogen from Ferrosilicon and a Solution of Sodium

Hydroxide (Methods of Study), to appear in Journal of Industrial and Chemical Engineering.

The Generation of Hydrogen from Ferrosilicon and Sodium Hydroxide (Details of Experiments and Recommendations), published in Fourth Annual Report National Advisory Committee for Aeronautics. The Use of Lime in the Generation of Hydrogen from Ferrosilicon and So- dium Hydroxide, published in Fourth Annual Report National Advisory Committee for Aeronautics. The Effect of the Presence of Sodium Carbonate on the Generation of Hydrogen from Fei'rasilicon and Sodium Hydroxide, published in Fourth Annual Report National Advisory Connnitlee for Aeronautics. The Use of Ultra-Violet Light for Testing Balloon Fabrics, published in Fourth Annual Report National Advisory Committee for Aeronautics.

Characteristic Exposure Tests of Balloon Fabrics, published in Fourth Annual Report National Advisory Committee for Aeronautics. The Testing of Hydrogen for Balloon Fabrics, published in Fourth Annual

Report National Advisory Committee for Aeronautics. Cemented Seams and Rubber Cements with Reference to Balloon Construction, published in Rubber Age and Tire News, volume 4, page 421, 1919." Baiioon Fabrics and their Testing, published in Textile World Journal, vol- ume 55, page 1047, 1919.

Scientitic Paper No. —, Efflux of Gases Through Small Orifices. Circular No. 81, Bibliography of Helium, also in Journal Industrial and Engineering Chemistry, volume 11, page G82, 1919. Technologic Paper No. 131, Application of the Gas Interferometer to Gas

Analysis.

Preparation and Testing of Pure Hydrogen, to appear in Journal of Industrial and Engineering Chemistry.

A Method for Determining the Permeabiliy of Balloon JFabrics, to appear in Journal of Industrial and Engineering Chemistry.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 151

The Significance of Oxygen in Balloon Gas, to appear in Aviation and Aeronautical Engineering.

Technologic Paper No. —, New Forms of Combustion Apparatus for Use in Gas Analysis, to appear also in Journal of Industrial and Engineering

Chemistry.

Technologic Paper No. 328, Effect of Solar Radiation on Balloon Fabrics. Automatic Methods of Gas Analysis Depending Upon Thermal Conductivity,

lu preparation.

Tlie Permeability of Rubber to Various Gases, in preparation.

Comparative Tests of Palau and Rhotanium Ware as Substitutes for Platinum

Laboratory Utensils, published in Journal Industrial and Engineering Chemistry, volume 11, page 570, 3919. Technologic Paper No. 1.36, the Determination of Free Carbon in Rubber

Goods, also in Journal of Industrial and Engineering Chemistry, volume 11, page 33, 1919.

. Mercerization of Cotton Yarns, to appear in Textile World Journal. Analyses of Different Tannages of Strap, Harness, and Side Leathers, to appear in Journal American Leather Chemists' Association. Technologic Paper No. 138, Effect of Glucose and Salts on the Wearing Quality of Sole Leather. Technologic Paper No. 138, Wear Resistance of Sole Leather. Technologic Paper No. 115, The Direct Determination of Rubber by the Nitrosite Method.

Metallic Coatings for Rustprooflng Iron and Steel, published in Chemical and

Metallurgical Engineering, volume 20, page 458, 1919. Technologic Paper No. 140, Constant Temperature Still-Head for Light-Oil

Fractionation, to appear also in Journal Industrial and Engineering Chemistry.

Circular No. 62 (revised). Specifications for and Methods of Testing Soap. Circular No. 82, Specification for Linseed Oil—Raw, Boiled, and Refined. Technologic Paper No. 132, The Mechanical Properties and Resistance to Corrosion of Light Alloys of Aluminum and Magnesium with Copper, with

Nickel, and with Manganese.

Circular No. 80, Protective Metallic Coatings for the Rustproofing of Iron and

Steel. PHYSICAL CHEMISTRY.

(rreparation and piirification of materials required in physical measurements of preci- sion—for example, refrigeration materials, calorimetric samples, materials for standard

cells, and for density determinations ; determination of ce -tain physical constants and

development of methods for their exact determination.) Refrigeration Materials and Problems.

In extension of the T^ork of the previous year additional samples

of pure ammonia were prepared for the making of vapor-pressure

determinations in the heat division. The presence of extremely

minute quantities of permanent gas affects these measurements considerably, particularly the ease with Avhich equilibrium is attained.

The method of testing for small quantities of permanent gas has

proved very useful in this work and in that of the density of the

gas (or Weight of a normal liter) as a criterion of purity. Littla

work on ammonia remains to be done, and a publication is in preparation on the purification and physical properties of ammonia which

will be quite extensive in scope. The plant installed for a study of gas formation in compi-ession

systems of refrigeration has been in operation for several months,

and a report upon the subject is contemplated for the next meeting

of the American Society of Refrigerating Engineers.

Purification of Materials for Special Purposes.

Standard samples.—Considerable work has been done on the re- newal of benzoic acid and naphthalene as standards for calorimetry.

The former, of satisfactory quality, was unobtainable during the
152 EEPOET OF DIRECTOR OF BUREAU OF STANDARDS.

war, but now rather large quantities of both raw materials are available from which to prepare the pure standards from time to time.

Facilities have been lacking heretofore for the purification of quantities large enough to last for more than a few months ; but the in- stallation of new and larger equipment will permit of preparing

stock to last for at least two years. Mercunj.—Mercury purification is now on practically a routine

basis. Aside from suppljdng the needs of the Bureau, material has

been furnished to the Geological Survey, the Weather Bureau, and

the Magnetic Laboratory of the Carnegie Institution. Considerable

work was done on methods of testing mercury as to purity, particularly by the measurement of its electromotive force. Methane.—Supplementing work of the previous year, several additional samples of pure methane were prepared for the determination

of its thermal properties by the heat division. The preparation of

this gas requires a very elaborate arrangement of apparatus and the

continuous attendance of operatives for as much as 48 hours at a

time.

Methyl alcohol.—Considerable attention was given to the purification of methyl alcohol for use in determinations of density by the

division of weights and measures. A series of samples from various

sources was prepared and tested for purity by use of the critical solution-temperature method.

Critical Solution Temperature Work.

Experimental work is being conducted on the quantitative application of the critical solution-temperature phenomenon (1) as a

criterion of the purity of chemical substances; (2) to the determination of the composition and constituents of petroleum products,

especiallj'^ gasoline; (3) to the determination of the quantity of

water absorbed by gasoline, transformer oils, and other products

which dissolve small quantities of water; (4) the miscibility relations

of the alcohols and hj^drocarbon mixtures, such as kerosene, as bearing on the utilization of the higher boiling hydrocarbons as internalcombustion motor fuels. The fundamental data necessary to the application of this method

to the problems listed above are the equilibrium relations in the

various binary systems, showing two liquid layer phenomena with an upper critical solution temperature (the temperature above which

two liquid layers can not exist). Methyl alcohol, ethyl alcohol,

aniline, nitrobenzene, and formic acid are substances which show

these phenomena with certain compounds and types of compounds

forming the constituents of the lower-boiling petroleum products.

The change in the value of the critical solution temperature of these

substances with various types of hydrocarbons and with various

members of the same series promises to contribute materially to our knowledge of the constituents of gasolines and the analytical methods which can be applied to this very complicated problem. The

data obtained from these solubility curves are also available for

purity tests of different samples of the various substances involved.

Methyl alcohol used in this work has been checked as to purity with

pure samples of carbon disulfide. The equilibrium relations be- tween these two substances have been determined, as well as those in

the system ethyl alcohol—carbon disulfide. Several samples of
KEPORT OF DIEECTOB OF BUREAU OF STANDARDS. 153

commercial aniline have been tested and purified and used in the

examination of gasolines. In addition to the characterization of

types of gasolines by this phenomenon, it is found that the great

effect of water on systems of this type can be utilized in determining

small quantities of water and the solubility of water in liquids dis- solving water sparingly. Before applications of this kind can bo

made it is necessary to determine the effect of known quantities of

water added to the system. The work is progressing mainly toward

the acquisition of the fundamental data necessary preliminary to the practical application of the method to more specialized engineering or technical problems.

Determination of Physical Constants.—It is aimed to provide

equipment and permanent arrangements for the precise determination of some of the more commonly used physical constants, particularly those useful to organic chemists in the identification of compounds. Thus far most attention has been paid to freezing-point

determinations of mixtures as well as single substances ; for instance,

of various samples of motor fuels. It is expected to extend the work

to the determination of boiling points, refractive indices, and

densities.

Glass-to-Metal Joint.—A glass-to-metal joint has been devised and

used very successfully in work with gases under high pressure. The

joint is tight under a complete vacuum and is resistant to very high

pressures, facts which make it very useful in laboratory work in

physical chemistry.

Atlas of Heterogeneous Equilibria.

In the report for 1916 reference was made to a proposed atlas of

heterogeneous equilibria. Work on this compilation has progressed

satisfactorily, and the information so far accumulated has been very

useful in the work of the chemistry division and in the correspondence referred to it. ELECTROCHEMISTRY.

(Electrodeposition, including electrotyping and electroplating, the latter including in- vestigations of zinc, lead, nickel, copper, silver plating, etc.)

Electroplating.

During the first half of the fiscal year the section was actively

engaged in problems connected with the electroplating of military

supplies. Such problems were very numerous and varied and in- volved a great amount of travel and conference with manufacturers

and military officials. While in most cases the military applications

of plating were, or appeared to be, incidental, the prompt delivery

of materials and the durability of the prodticts during storage and

transportation or in field use, were often dertermined by the success or failure of the plating operations. The need for definite information was emphasized by the almost absolute lack of commercial standards or specifications, in consequence of which fact delays and con- fusion were not unusual. Through conferences with manufacturers

and military officials this Bureau was able to suggest tentative specifications which were mutually satisfactoi-y. In general, in such

specifications the purpose was to give as much latitude to the manufacturers as would permit satisfactory products, and also to unify
154 KEPOKT OF DIRECTOR OF BUREAU OF STANDARDS.

and systematize, so far as possible, the requirements of different

military branches for similar products or for materials subject to similar use and exposure.

The research work carried on at the Bureau was devoted principally to meeting immediate military needs. Consequently it was

not possible to conduct any exhaustive or detailed investigations.

Nevertheless, much information of value to the plating industry was

obtained, and an acquaintance with platers ancl manufacturers and

their needs was secured which will, it is believed, be of great value

in further research in this field. The principal military applications of electroplating which were

investigated at the Bureau were as follows

Lead Plating.—This had very little commercial application prior

to June, 1918, at which time a demand arose for lead coatings in

connection with gas shells. Within a few months a considerable

number of plants were prepared to carry out this operation, using

either fluosilicate or fluoborate solutions. In view of certain advantages possessed by the latter solutions, they were investigated by

this Bureau, and working directions were furnished to manufacturers. Other applications of lead plating were the bringing up to weight of underweight shells, of which many thousands were thus

salvaged, ancl, to a less extent, the lining of chemical equipment.

Possible commercial applications of lead plating are being investigated.

Black Nickel Plating.—This operation was very extensively used

to produce a black finish upon military equipment. The formulas

in commercial use were very involved and frequently unsatisfactory.

As a result of investigations at the Bureau, simple satisfactory

formulas were recommended.

ZhiG Plating.—In view of the fact that zinc is the only metal that

furnishes intrinsic protection! against cori-osion of steel, zinc coat- ings have proved very valuable. Of the three methods of producing

satisfactory zinc coatings—viz, hot dipping, sherardizing, and zinc

plating (electrogalvanizing) —the latter is frequently most convenient, especially for small parts, or those which are threaded or dimensioned or those having previous heat treatment ancl which

might be injured by reheating. Itj was found that entirely satis- factory zinc plating can be conducted in either cyanide or sulphate

solutions. Eesults of the investigation of the cyanide solutions have

been published, and the work on sulphate solutions is still in progress. There were many minor military problems and applications of

electroplating submitted for consideration, all of which showed the

need in this industry for better definition of methods of plating and

of testing plated products. Throughout in these investigations the

Bureau has had the active support and cooperation of the American

Electroplaters' Society, three of whose members, at considerable

financial sacrifice, devoted their entire time to this work. With the

cessation of hostilities and the consequent reduction in military demands and financial support it was no longer possible to retain any

considerable staff upon electroplating problems. In view, however,

of the importance and far-reaching applications of electrocleposition,

arrangements have been made to devote a limited sum from the

industrial research fund to these investigations during the fiscal
REPORT OF DIRECTOR OE BTTREATT OE STANDARDS. 155

year 1919-20. In addition, it is hoped that some financial support

ma}'' be furnished by manufacturers interested in phiting.

While these investigations will be conducted with a view to secur- ing information of industrial value and to publishing it in a form

useful to practical platers, experience has shown that permanent

and far-reaching progress in this field must involve fundamental

studies of electrodeposition, requiring tlie services of persons es- pecially qualified, in physical and analytical chemistry and metallography, and at least one person thoroughly acquainted with the

present methods and needs of the electroplating industr3\ The possible scope of work in this field may be judged by the many kinds of

electroplating which find application in the most varied industries.

Tlius, in addition to the lead, zinc, and black nickel i^lating previously referred to, nickel, silver, brass, copper, gold, and tin i)lat- ing are all extensively emploj^ed. Progress in this field Avill involve

a considerable annual expenditure, which, however, is fully warranted by the importance of electrodeposition in its varied applications.

METALLURGICAL CHEMISTRY.

(Preparation of metals and alloys required In connection with metallurgical investigations and special methods of analysis for such products.) The work done by the chemistry division, in connection with

Txietallurgy, is reported under "Metallurgy" (p. 258).

GAS CHEMISTRY.

(Methods of preparation, purification, analysis, and testing of gases, incUiding fuel and

Illuminating gas, and special gases, such as hydrogen, oxygen, nitrogen, and argon.) The two most important and extended lines of work carried on

by the gas section during the past year were (1) the testing and

investigation of the properties of balloon fabrics and (2) the develojDment of a method of automatic gas analysis, the possibilities

of which have not heretofore been appreciated. The other investigations carried out by the section, in most of which the Bureau

served the military and naval departments in the capacity of a considting chemical engineer, were of too varied a nature to permit

classification. Thirty-two reports and publications were made or

are in preparation.

Balloon Fabrics.

The testing of balloon fabrics for permeability and lasting qualities has continued along the lines so well established during the

preceding year. The volume of work has been very large, not only

during the war, but since the signing of the armistice, because of

the extensive experimental program of the Navy. The total number of fabrics tested during the year was 710, 1,520 individual tests of various kinds being involved.

In addition to this regular testing work, investigations were made along the following lines

:

1. The permeability of various materials to helium. An investigation to determme the suitability of the present fabrics for making

helium balloons and, if possible, to develop improved fabrics for

the purpose. The properties of ordinary fabrics have been well
156 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

ascertained, but no improved fabric for use with helium has

resulted.

2. The permeability of rubber to various gases. An investig^ition

made to. determine not only the usefulness of rubber as a container

for various gases, but also to shed light on the mechanism of permeability.

3. The relation of the thickness of rubber films to permeability.

4. The relation to permeability of the partial pressure of a gas

and the nature of its diluent.

5. The relation of temperature to the permeability of rubber

films. The principal significance of (4) and (5) is in connection

with testing methods.

6. The effect of solar radiation on balloons. This investigation

included the heating of the fabric and the temperatures in various

parts of the balloon, convection losses from balloons in flight, the

effect of radiation on the lasting qualities of the fabric, the protection of the fabric from injurious effects, and the effect of ^Digments

in fabrics upon the changes of balloon temperature and the visibility

of balloons.

7. The microscopic examination of fabrics. This work, carried out upon transverse sections, proved of great assistance in connection with a number of problems, but particularly in connection with

cements and seams.

8. Acidity tests of fabric. It was found that a part of the deterioi'ation of the fabrics in service was caused by sulphuric acid

formed by the oxidation of the sulphur used in compounding the

rubber.

9. The relation of permeability to the thread count of the fabric.

Shortly before the signing of the armistice this problem assumed

considerable importance, because the production of balloon fabrics

at that time a]3peared to be limited by the possible output of the

machinery available for the manufacture of the very fine fabrics

used for the purpose.

10. The deterioration of fabrics under tension. This investigation was intended to supply information relative to the abnormally

short life of dirigibles in service. No conclusive results were

obtained.

11. A comparison of the American and Italian methods of making

life tests of fabrics. This investigation is still continuing. Thus

far there is no indication that the Italian method (exposure to the

weather with hydrogen on one side) is superior to the American

methods.

12. A comparison of the English and American methods for making permeability tests. 13. A study of exposure tests of fabrics at Washington and Pensacola. A study of the significance of various meteorological conditions in the deterioration of the. fabrics.

14. The effect upon balloon fabrics of impurities in hydrogen and

of contact with metal fastenings. These tests showed what metals

could be safely used in balloon construction, and indicated that the

elimination of the last traces of gaseous impurities from hydrogen

is unnecessary.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 157

15. A stud}^ of balloon seams and rubber cements for making

seams. This work gave some vei'y valuable information regarding

the construction and causes of failure of balloon seams.

16. The development of two more rapid methods of making routine

permeability tests which should be of considerable importance in case sudden rapid expansion of balloon production is again required.

17. The determination and partial elimination of a source of error

in making permeability tests due to the passage of gas between the

layers of fabric.

Tlie above investigations were all carried out in the closest cooperation with the Army, the Navy, and the manufacturers; and since none of these parties had any adequate facilities or personnel for the

study of such problems, the work done by the bureau may be regarded

as of fundamental importance. Many reports and publications on

these subjects have been made or are in preparation.

Automatic Gas-Analysis Apparatus.

Without doubt, the work of most importance to American industry

accomplished by the section during the year was the development of some simple and extremely sensitive apparatus and methods for the

automatic analysis of gases. This work was undertaken at the re- quest of the Nitrate Division of the Ordnance Department in connection with the analysis of the complex gas mixtures employed in the

synthetic manufacture of ammonia. Apparatus was designed and

the measuring instruments had been constructed and calibrated for

the chemical control of the big plant at Sheffield, Ala., when the armistice was signed and work at that plant ceased. A smaller apparatus

has, however, been constructed for the use of the experimental plant

at Arlington and is now in use at that place.

Apparatus was also constructed for recording the percentage of

helium in the preparation of that gas for balloon purposes and has

been installed in the fractionating plant at Petrolia, Tex. This apparatus, after installation, was also adapted for recording the composition of the raw gas entering the plant. Similar apparatus for

making and recording 12 continuous analyses simultaneously is now

under construction for use in the big helium plant at Fort Worth.

This type of apparatus has been tried out successfully for so many

purposes that the following list of the determinations possible by

this method seems justified: (1) Practically any binary mixture of

which the constituents are known. (2) Practically any easily absorbable constituent of a gas mixture containing no other constituent

which reacts with the I'eagent used. (3) Any single combustible gas

in air or oxygen. (4) Oxygen, hydrogen, nitrogen, carbon monoxide,

and carbon dioxide in mixtures containing these gases only. (5)

Total carbon or total carbon, except carbon dioxide, in most gas mixtures of industrial importance. (6) Oxygen required to burn any

ordinary reducing gas mixture or oxygen required to burn all the re- ducing constituents except hydrogen. (7) Hydrogen or helium in

any ordinary mixture. Many other combinations are, of course, possible. A single electrical measuring instrument or recorder can be

easily adjusted to read any one of several such analyses on the same

decimal scale or to read directly a linear function of the composition,

such, for instance, as the permeability of fabrics in suitable units.

The apparatus can also be made to automatically control various
158 REPORT OF DIEECTOR OE BUREAU OF STANDARDS.

mechanisms. The analysis of flue gases, mine air, blast-furnance

gases, and many industrial gases can probably be put on a recording

basis with apparatus much superior to any now in use for similar

purposes.

One of the foremost instrument manufacturers in the country is to undertake the manufacture of this apparatus in the near future.

Miscellaneous Problems.

1. A determination was made of the limits of inflammability of

mixtures of hydrogen and helium, particularly when issuing from

orifices of various sizes. A considerable amount of work was also

done on the analysis of helium mixtures in connection with the nu- merous problems involving that gas.

2. The bibliography of helium literature was revised.

3. A technical report was rendered on the practicability of producing ammonia as a by-product in the separation of helium from

natural gas, according to a method proposed by the engineering laboratory of the United States Naval Academy.

4. Analyses of the exhaust gases from airplane engines were made

throughout most of the year for the gas-engine section.

6. A considerable amount of work was done upon the selective combustion of carbon monoxide in gas analysis, and upon the determination of carbon dioxide, of water, and of ammonia in very small

amounts in gases by electrolytic conductivity methods. Some of the

methods studied give promise of usefulness when there is opportunity

to develop them further.

6. Tests were made at Langley Field to determine the performance,

as to yield and purity, ©f the large hydrogen plant installed there. Acceptance of the plant and the compensation paid the contractor was based on these tests.

7. A considerable amount of time was devoted to cooperative test" with the Bureau of Aircraft Production upon the ignition of balloonsi

by incendiary bullets.

8. A number of useful pieces of apparatus and methods of laboratory work were developed. The most important of these is a form

of bridge for measuring directly the difference of conductivity of

two electrolytes.

9. A determination of the temperature of inflammability of organic

material in contact with sodium nitrate was made for the Eailroad

Administration. This problem arose in connection with the stoi'age

of this material in warehouses and docks.

REAGENTS AND APPARATUS.

(Study of methods of tpsting reagents and apparatus to be used in chemical analysis, including study of chemical glassware, porcelain, platinum, and platinum substitutes.)

Chemical Reagents.

Owing to the limited force, abnormal conditions, and the miscellaneous tests made for the Military Establishments, little jorogress has

been made in the study of the methods of analysis of the so-called " anah'zed reagents." Most of the work has consisted in the testing

of reagents purchased for the use of the laboratories of this Bureau. This work indicates that there is room for improvement in

most, if not all, of the reagents tested. This study having been taken
EEPOET or DIRECTOR OP BTJKEATJ OF STA2<n5AEDS. 159

up in cooperation with the American Chemical Society and the manufacturers, a report has been submitted to the chairman of the committee on analyzed reagents of the American Chemical Society, and

manufacturers advised of the discrepancies between the printed labels and the actual findings. A S3'ncpsis of this report was published in

the Proceedings of the American Chemical Society, 1919. As the

quality of chemical reagents is of direct interest to all scientific and

industrial laboratories, and indirectly alfects all users of the products of the industries, means should be provided for prosecuting this

work in a systematic way.

Platinum.

The research upon the chemical and physical properties of the

platinum metals has been continued. The analytical methods given

in the literature have been studied and the inform-ation so obtained applied in the examination of various samples submitted for test. The

preliminary purification of platinum, palladium, and iridium has been

completed, and the study of the physical properties of the pure metals

will soon be taken up. Analyses were made of platinum gauzes for

use as catalysts in the oxidation of ammonia by the Xitrate Division

of the Ordnance Bureau. Owing to the price of iridium and the

necessit}^ for conservation, the Bureau of Aircraft Production had

prepared platinum-iridium alloys containing varying percentages of

iridium to be used in the manufacture of magneto contact points.

Service tests and chemical analyses were made by this Bureau. The

analyses showed that only about 50 per cent of the iridium content claimed was found in each case. The standard platinum-iridium

alloys in general use contain 15 to 20 per cent of iridium. This work

was discontinued on the signing of the armistice.

Negative tests of reputed platinum ores were made at the request

of Government offices, analyses of various platinum metals were made

for the United States assay office, and miscellaneous tests made and

reports rendered for military branches of the Government.

Through the cooperation of the nitrate division of the Ordnance

Department, United States Armj', the Bureau has received for use

in research 72 ounces of platinum residues from the United States assay office. Unfortunately, the important metal rhodium was found

to b3 almost lacking in these residues.

The United States assay office, continuing its cooperation of the

previous year, has made for the Bureau many vessels and articles

of platinum and some of gold.

Platinum Substitutes.

The shortage of platinum shortly before and during the war

arorsed the interest both of commercial organizations and the public in general. Quite a number of " platinum substitutes " were developed and samples submitted to this Bureau for test. Most of this

work was done for the platinum section of the AVar Industries Board.

The substitutes proposed for platinum were of two kinds ; those composed of base metals, and alloys of the noble metals. No base metal

substitute was submitted which approached platinum in general use- fulness or was suitable for laboratory operations. Two base metal

alloys were examined which were found suitable for the purposes for

which they were designed. One was an alio}- very resistant to nitric
160 REPORT OF DIRECTOE OF BUREAU OF STANDARDS.

acid and submitted by the nitrate division; the other could be used

for electrical contact points under a limited range of conditions. In

one case steps were taken to suppress wildly extravagant advertising.

Of the noble-metal alloys two were examined, known as " palau " and '-' rhotanium." Both are alloys of gold with relatively small

amounts of palladium. These were tested in conjimction with the

metallurgical division and were found suitable substitutes for platinum in numerous operations in the chemical laboratory.

Miscellaneous Tests. Various miscellaneous tests vrere made for military and other offices, among which were (a) enamel ware, (h) lead, barium, and borosilicate optical glasses, (c) aluminum sulphate (inspection and sampling of a 500.000-ton lot for the Panama Canal).

ANALYTICAL METHODS AND STANDARD SAMPLES.

(General methods of chemical analysis, with special reference to methods of standardization ; preparation and analysis of standard samples of iron, steel alloys, ores, chemicals, etc.) Standard Analyzed Samples.

The number of standard samples called for during the fiscal year

1919 was 4,944, an increase of 108 over the previous year. The dis- tribution was as follows: Irons and steels, 3,627; brass, 93; ores, 307; sodium oxalate, 325; naphthalene, 87; benzoic acid, 108; sucrose, 95; dextrose, 16; metals for melting points, 154; cement for testing

sieves, 132. The greatly increased calls for standard samples during the war

left the Bureau with a much-depleted stock. This necessitated a curtailment of the distribution. In this connection it should be

pointed out that the money value of the samples issued was more

than twice the total appropriation for the work, namely, $4,000.

Even with the fund available for the fiscal year 1919—namely,

$5,000—it will be impossible to keep up the stock of samples already

listed. The preparation of samples has been confined entirely to the

renewal of the stocks of those listed. The private enterprise in England mentioned in the last annual

report requested the Bureau to cooperate in the analysis of a standard sample of chrome-vanadium steel, and to secure the cooperation

of two outside analysts.

Determination of Tungsten, Molybdenum, Zirconium, and Uranium

in Ores and Metallurgical Products.

Continuing the cooperative work referred to in the last annual

report, methods have been worked out for the determination of

tungsten, molybdenum, zirconium, and uranium in metallurgical

products and in ores of the three first-named metals.

Miscellaneous Researches.

In addition to the above researches a number of others have been

carried out, which served to clear up obscure points in analysis,

namely, precipitation of zirconium as phosphate, volatility of phosphoric acid upon fuming with sulphuric acid and fusion with alkali

pyrosulphate, determination of small amounts of aluminum in pres- ence of large amounts of zinc, determination of small amounts of

calcirmi in presence of large amounts of magnesium, study of tern-
KEPOKT OF DIRECTOR OF BUREAU OF STANDARDS. 161

peratures obtainable with the ordinary types of laboratory burners,

behavior of manganese and vanadium in the precipitation of iron and

aluminum with ammonium hydroxide, according to the procedure of

Blum.

LUBRICATING OILS, RUBBER, PAPER, TEXTILES, INK, AND GLUE.

(Chemical analysis and investigations of oils, rubber, paper,, textiles, ink, glue, air- plane dopes, etc., with special reference to meeting particular requirements.)

Airplane Dopes.

After the Signal Corj)s established its own laboratory in Pittsburgh, Pa., work was continued for the Bureau of Construction and

Eepair, Nav}^ Department, not only until the signing of the armistice, but up to the present time. Numerous trips were made to manufactories of dopes and of airplanes, as well as to aviation fields, in

the interest of the Navy.

Early in this calendar year the Department of Military Aeronautics, which had taken over the aviation program of the Signal

Corps, found it advisable to return to the Bureau for assistance in

the preparation of a lengthy report on foreign practice in doping

and related matters. Part of the statements made by military -ob- servers abroad were of such doubtful reliability and so o^Den to question that this Bureau was asked to test many of them by laboratory

experiments.

Chemistry of Leather.

Full details of the Bureau's work on leather, including that of the

chemistry division, are given in the report entitled "Leather" (p.

224).

Chemistry of Rubber.

Full details of the Bureau's work on rubber, including that of the

chemisti-y division, are given in the report on rubber (p. 220).

Chemistry of Textiles and Commercial Dyes.

Full details of the Bureau's work on textiles and commercial dyes,

including that of the chemistry division, ai'e given in the report of

the textile section of Division VII (p. 227).

Pure Dyes.

A great deal of time was devoted to the preparation of about 30

carefully made and purified dyes. This was done in connection with

the projected develoiDinent of a comprehensive method for the identification and analysis of dyes by spectroscopic measurements. Commercial dyes can not be used to obtain the fundamental data, because

they are rarely single, pure substances, but generally contain colored

organic impurities. Different salts of metals are also frequently

admixed. It is obviously impossible to determine the character and

intensity of color of the dye in such a mixture.

Camouflage.

A statement of the work on dyed fabrics and screens for camouflage and secret signals appears in the report of Division IV.

142289—19 11
162 KEPOET OP DIKECTOB OP BUREAU OF STANDAEDS.

Photographic Sensitizers.

One of the most valuable dyestuffs for sensitizing photographic

plates to certain portions of the spectrum is dicyanin. This is a German product. Very little has been published about its chemical

nature or the method of preparing it, and that little is probably misleading or lacking in some important detail. Attempts to produce

dicyanin led to the discovery of a dye which is in some respects

superior to it. Chemistry of Inks.

Writing and Copying Inks.—A great many writing and copyinginks were tested to assist the General Supply Committee and the

Post Office Department in awarding contracts, and also to check deliveries made by contractors. There was evident an increasing tendency to manufacture inks from Prussian blue. This color is very

pei-manent under some conditions, but has the disadvantages of not

turning black and of being readily removable by a simple chemical

treatment. The most suitable inks for permanent writing contain iron gallo- tannate. On the paper this soon oxidizes to an intense black, al- though the writing is at fii-st very pale. To get around this, a suit- able dye is always used. For a considerable time after the supply

of German dyes was exhausted American ink manufacturers had

great difficulty in getting suitable dyes. The Bureau learned where

satisfactory colors were made, and was thus able to help more than

one ink manufacturers to improve his product.

Ink Tablets and Powders.—For many years various brands of

tablets and powders for making writing ink by simply dissolving

them in water have been on the market. They are more convenient

than ink in liquid form, because they occupy so little space in shipment and storage; they can not freeze and break the bottles; they

keep indefinitely; and they can be sent safely by mail. For these

and other reasons the Army sent many thousands of tablets and powders abroad. The same reasons appeal to the Post Office Department, which supplies post offices throughout the country from Washington.

Until recently these powders and tablets have been made of " aniline," or, more correctly, synthetic, dyes. Such inks can not have

sufficient permanence for record inks, and for that reason the Bureau

has consistently refused to recommend them for use by the Government departments.

Eed and other colored inks are necessarily made from dyes. It

is immaterial whether these are put on the market in solid or liquid

form.

Within the past year a few brands of gallotannate of iron tablets

have been tested by the Bureau. Some of these Avere of a fairly satis- factory quality, but others were not only turbid when freshly dis- solved, but the ink so prepared deposited large quantities of a thick,

gummy sediment in a few days. Properly made liquid inks give

very little sediment, because enough hydrochloric or other mineral

acid is added to keep the iron compounds in solution. These acids,

being liquids, can not be used in powders and tablets. The Bureau

found that solid organic acids such as oxalic, or acid salts such as
REPOET OF DIRECTOR OF BUREAU OF STANDARDS. 163

feoclium bisulphate, can be used with success. This information was

passed on to manufacturers of this type of ink.

Concentrated Inks.—Possibly owing to the difficulty of making

suitable ink powders and tablets, some manufacturers have recently

placed concentrated inks on the market. If properly made and not

too greatly diluted, there is no reason why they should not be used

for permanent records.

Indelible Inks.—A considerable quantity of indelible ink was used

bv various branches of the military organization for marking blankets, bales, etc. A great variety of materials was used in making these

inks. By laboratory tests and by washing in a commercial laundry

it was learned that a dye of good quality, dissolved in cresol, made

the most permanent ink.

Miscellaneous Inks.—Among other classes of inlc tested were the

following: Stamping, drawing, and stenciling inks, and those to be

used with canceling machines, duplicators, and hektogi^aphs.

Typewriter' Ribbons.—Man}' ribbons for use on typewriters, as well

as similar ribbons for time recorders, adding and computing machines, etc., were examined and tested. The quality of the fabric,

the amount of ink, and the permanence of the writing were all. considered in making the tests. Carbon Papers.—Comparatively few carbon papers were received

for test. The Aveight and quality of the paper, and the nature and

amount of the coating were determined.

Printing Inks.

The Bureau made only a few analyses of printing inks, but much

time was spent in devising a method for determining the properties

known to printers as "tack," "length," or "shortness," and "carrying

power " of vehicles, the oil absorption of pigments, and the rate of

setting vehicles and inks. By this method the results are expressed

numerically and duplicate determinations give closely concordant

figures.

Some progress has been made in correlating the data obtained in

the laboratory with the behavior of the inks on the press, but many

phases of the subject remaining to be investigated before the work

can be regarded as complete.

Printers' Rollers.

Printers' rollers are made of glue, water, and molasses or glycerol.

A difficulty with rollers made with cane molasses is that they can not

be melted and recast after they have become hardened in service. The

Bureau devised and patented a method of using specially prepared

beet molasses instead of cane molasses. The behavior of these rollers in service shoAvs that they can be used much longer than the other

without hardening. They can also be remelted.

The patent (United States 1,284,172), issued November 5, 1918, was dedicated to the public.

Glue, Mucilage, Paste. About 100 samples of glue, mucilage, and paste were tested for the

Government.

Miscellaneous.

Among the minor items in which the section was interested were

:

Paper boxes for shoe polish, safety matches, linoleum pastes ; exam-
164 KBPOKT OF DIRECTOR OF BUREAU OF STANDARDS.

ining mangrove roots for tannin and dyestuffs; examining morinda

roots for dyestiiffs; preparing inks for recording instruments and

for use in connection with the etching of graduated glassware ; preparation of a liquid for use on mimeograph stencils; bleaching freshwater pearl buttons, etc.

^ Examination of Materials for the Steamboat-Inspection Service.

The Steamboat-Inspection Service depends upon the Bureau not only for the testing of goods that may possibly be prohibited on pas- senger steamers but also for options as to the propriety of cariying

chemicals and other similar substances.

The Bureau agrees with the service that the existing Federal law

(Sec. 4472, E. S.), which was passed 45 or more years ago and which

has been amended several times, is self-contradictory and hampering

to foreign trade. The Steamboat-Inspection Service and the Bureau

of Standards independently made recommendations to the Secretary

of Commerce that steps be taken to have this old statute replaced by

one abreast of the times. Their suggested outlines for a new law were

surprisingly alike. METALS, CEMENT, AND BITUMINOUS MATERIALS.

(Chemical analysis of metals, including iron, steel, nonferrous metals, alloys, such as

brass, type metal, and solder ; coated metals, such as tin plate and galvanized metals ; lime

plaster, cement, concrete, bituminous materials, including tars, asphalt roofing papers,

roofing felt, etc.) Chemical Work on Metals and Alloys.

In addition to a large amount of routine testing of metals and

alloys, much attention has been given to trying out and improving

methods of chemical testing. Many tests were made for the purpose

of supplying information to other divisions of the Bureau to aid in

determining the most suitable materials for various military needs

and to explain causes of failure. A number of special metals and

alloys were analj^zed.

An exposure test to determine the relative resistance to corrosion of

uncoated sheet iron and steel was made in cooperation with the Post

Office Department. Sheets were exposed on post offices in several

large cities and subsequently compared at the Bureau. The use of

sheet steel containing from 0.15 to 0.25 per cent of copper was recom- mended.

Protective Metallic Coatings.

For various branches of the War and Navy Departments tests were made of numerous samples of metal rustproofecl by different companies and by different methods.

The method of stripping zinc-coated metal referred to in last year's

report—by means of sulphuric acid and sodium bichromate—has

been critically examined and found to be unsatisfactory for commer

cial application. However, careful application of the test will give a fair estimate of the amount of zinc applied.

Salt-spray tests on aluminum alloys, started in 1917 in cooperation Avith the metallurgy division, were completed and reported upon

in Technologic Papers Nos. 132 and 139. Corrosion tests were made for the Engineering Division of the

Ordnance Department on German silver and " aluminized " (tincoated) steel hinges for meat cans. Considering the advantages of
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 165

using steel, the tin-coated hinges were regarded as superior to those

of German silver, but, in order to conserve tin, zinc-coated steel was

recommended.

A test for pinholes in lead plating was developed to indicate a satisfactor}' lead lining for gas shells. This consists in immersing the

plated steel in a solution containing 1 -per cent of sodium ferric_yanide

and 2 per cent of sulphuric acid. Pinholes are indicated by the

appearance of a characteristic blue precipitate.

Bituminous Materials.

Boofing.—The preparation of a standard specification for prepared

roofing discussed in last year's report became a reality; in conjunction with the War Trade Board the specification was prepared and

adopted. It included methods for inspection, testing, and instructions for inspectors; but with the cessation of the war the need of

maintaining a corps of inspectors at the plants passed. Millions of

squares of roofs obtained under this specification but laid under

high pressure failed in many cases to be satisfactory ; leaks developed which at first were blamed on the quality of the roofing used,

but from inspection it was evident that the fault was with the manner of laying and not the material. The development of a satisfactory

bituminous cement to rej)air the leaks enabled elf'ective repairs to be

made at a very moderate cost. Specifications for slate-surfaced and asphalt shingles were also

l^repared, but the specification for built-up roofing, which is required

under normal conditions, still remains to be developed, nor has it been possible to make a systematic inspection of the repaired roofs

which have been laid, and it will be unfortunate to lose this information, which is necessary to improve the specifications which have

been in use. Interior coating for steel ships.—The specification for the coating of

the interior of steel ships prepared originally for the United States Navy Yard at Philadelphia, and extended to apply to the bituminous

enamel used on the lock gates at Panama, has been modified by re- stricting the quantity of mineral filler and controlling the consistency of the development of a test which measures this condition

so as to improve the specification. This material has also found a

use for steel ships being built by the Emergency Fleet Corporation.

Interior coating for steel shells.—The Ordnance Department of

the Army asked for a specification for an inside coating for highexplosive shells and shrapnel. This coating should be free from

any lead or managenese compounds; it should not dry hard, but

remain tacky, so as to bond with the molten T. N. T. with whicli the

shells were charged; and should not have any efi^ect on the efficiency

of the explosive. A Gilsonite fluxed with a soft Bernuidez asphalt

and thinned with a light volatile petroleum product appeared to give

a satisfactory coating.

Coating for grenades.—The Ordnance Department also desii'ed a- coating for hand and rifle grenades. Hand and rifle grenades re- quire a coating which will dry hard on a greasy surface, as it is not

practicable to clean them after machining. A hot coal-tar pitch of

relatively low penetration and high melting point was being developed for this purpose when the closing of hostilities practically

stopped production of grenades.
166 REPORT OF DIRECTOR OF BUREAU OE STANDARDS.

Coatings for Concrete Ships.

The concrete ship was a new venture and required special treat- ment. A ship is subjected to great and various strains and can not

be made perfectly rigid. Concrete is usually considered a rigid material, but in fact it is elastic, and if it is properly reinforced it will stand much distortion without failure. Small hair cracks may

develop, and it was the problem to cover the outside of the structure with an elastic waterproof membrane which would bridge such

small cracks. The coating must not be affected by water, must not

flow when subjected to the pressure of the water when the vessel runs at maximum speed, and must present a suitable surface for the

application of antifouling, boot-topping, and camouflage paints over

it. All of these conditions were considered, and a number of products tested in an effort to obtain one which seemed to best meet conditions of service. Two compositions were recommended, and further

work is in progress. Another problem in connection with the concrete ships was to provide an inside coating for oil tanks. Many of these ships were

to be used as oil tankers for the transportation of a variety of crude

and refined oils. The problem was complicated by the presence of

water in the oil, and also by the fact that these tanks might fre- quently be filled with water as ballast on return trips, so the coat- ing must be resistant to both water and oil. After an extended

investigation it was recommended that a Chinawood oil-resin varnish, commonly called " spar " varnish, was the best available material. This, however, is not entirely satisfactory, and nothing better has yet been tried. It is believed that failures have been more

due to faulty methods of application and to expecting more than

could possibly be obtained from a paintlike coating than to actual

inferiority of material used. Probably the life of the best coatings

aA'ailable will always be short. Marine Glue.

In an attempt to meet the requirement of the Naval Hj^droplane

Service for a marine glue for pontoons the original Jeffreys marine

glue, made in England, was examined, as well as the present foreign

product and domestic substitutes, in the hope that a material might

be developed which would make this country independent of foreign

production. Neither the present foreign product nor the domestic

substitutes were found to be entirely satisfactory, but it was found

that Manila or similar varnish resins, with pine tar and rubber,

thinned to proper consistency, also blown Mexican or Texas asphalts

with gilsonite and a mineral filler thinned to proper consistency

Were satisfactory.

Linoleum Cement.

The Bureau of Construction and Repair, Navy Department, de-

-sired information on linoleum cement. It was found that the shellac

cements, with alcohol as a thinner and with or without a finely

powdered mineral filler, were more waterproof and held the linoleum more tenaciously to the concrete or steel than those cements made

from dextrin or other water-soluble gums or from other resins cut

in alcohol. Shellac cements with mineral filler adhered more tena- ciously and did not become brittle on drying, as did shellac cut in
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 167

alcohol without the filler. When watei'-soluble pastes were used it was recommended that a strip 1 foot on either side of the seams and

edges should be cemented with a waterproof cement to keep out

moisture and thus prevent the paste from molding. The Bureau of

Construction and Repair have reported since the above recommendation that the failure of the water-soluble pastes was due to moisture

in the cement floor, and when this was prevented by thorough drying they were justified in accepting the guarantee of the contractor,

and have used this cheaper type of linoleum cement. Oakum.

A specification was also developed through cooperation with the

textile division for oakum for the Emergency Fleet Corporation,

which, as far as can be learned, is the first definite specification for

this material.

Separation of Benzol, Toluol, and Xylol.

As a result of the investigation made at the Roberts coke ovens

at Canal Dover, Ohio, a laboratory form of still head has been devised which gives remarkably sharp separation of benzol, toluol,

and xylol. This still head will be described in a technologic paperIt furnishes a laboratory method for the separation of these com- pounds and may have an application in their industrial separation.

Cement.

About 8,000 samples of cement were tested in the chemistry division. Full details of the Bureau's work on cement, including that

of the chemistrv division, are given in the report on cement, etc. (p. 195.)

Miscellaneous Tests. For the Railroad Administration some 60 samples of boiler-feed

water, boiler scale, and boiler compounds were analyzed to show, if possible, the merits of the Perolin treatment for boiler waters. This

work is still in progress. Many miscellaneous analyses and tests were made, covering sol- dering and Avelding fluxes, magnesia-asbestos preparations, furnace

cements, aluminum sulphate for treating water, water from military

camps, protective backing for mirrored surfaces, fire-extinguishing

liquids, etc. PAINT, VARNISH, AND SOAP.

(Cbemical analysis, testing, and exposure tests of paint and varnish ; chemical analysis of and specifications for soap.) Paint Specifications.

Interdepartmental Committee on Paint Specification Standardization.—At the suggestion of the War Industries Board that the Department of Commerce attempt to prepare uniform standard specifications for paint materials, a conference of representatives of all the interested branches of the Government service was held at the

Bureau on February 26, 1919. This conference recommended that an interdepartmental committee on paint-specification standardization be organized. This committee was organized and at present

consists of one representative each from the War, Navy, Interior,

Treasury, Post Office, Agriculture, and Commerce Departments, the
168 KEPOKT OF DIRECTOR OF BUREAU OF STANDARDS.

Panama Canal, Eailroad Administration, and the Paint Manufacturers' Association. This committee has held a number of meetings

and has prepared and recommended the specification for linseed oil, raw, refined, and boiled, which has been issued as Bureau Circular No.

82. The committee is considering specifications for other paint materials, and it is hoped that a number of such specifications will be issued

within the next year. Miscellaneous Paint SjJeci-fications.—A great number of miscellaneous paint materials specifications have been prepared. Mention

may be made of two. The War Industries Board requested specifications for paint to be

used in housing projects for the Government and that an especial at- tempt be made to have these specifications cover the use of materials

entirely of American origin. As a result of our cooperation with

manufacturers and other experts, the War Industries Board paint

committee recommended to the Housing Corporation specifications

for a number of paints to be used on wooden houses.

In accordance with a request from the Forest Service, Department

of Agriculture, specifications for white, cream, drab, cinnamonbrown, and green paints were furnished.

Projectile Paints.—In the latter part of the fiscal year ending June

30, 1918, and extending over to the present fiscal year, a large number

of samples of very rapid drying paints for use on projectiles were

tested at the request of War Department officials, and specifications were prepared and sent to the Edgewood Arsenal, Baltimore. Paints

covered by this specification are ver}^ rapid-drying and were designed

for use during periods of heavy production. The War Department,

however, has specifications for projectile paint of a different nature

than the above-mentioned, being much slower in drying, and the Bureau has not been able to learn which type of paint has been actually

used by the War Department, although it would appear that the tj'^pe contemplated by the Bureau's specification is far superior for periods

of intense production than the material specified by the War Department.

Protective Coatings for Ordnance Stores. After the signing of the armistice the Ordnance Department

asked for advice relative to the painting of guns, shells, and other

equipment for storage. Experiments were carried out to determine

the thickness of films on shells after brushing and spraying, and it was found that three coats' of paint could be applied to shells without

increasing the diameter to exceed the tolerances permitted. Recommendations were made as to the character of paint to be used for

storing this type of equipment.

In addition to requests from the Army officers regarding methods

of painting ordnance stores, a large number of requests came in re- garding the use of oily coatings generally known as slushing oils. Formerly these materials were used for protecting bright parts of

machinery for only short periods, and there is no information available as to the length of time that such coatings will afford protection.

After examining a large number of samples of such materials, some mimeographed notes on protecting metal in storage were furnished

to a large number of Army officers. They contain a general state- ment of the nature of such materials and proposed specifications for

three types.
EEPORT OF DIKECTOK OF BUEEAU OF STANDARDS. 169

Tests of Water Resistance of Enamels and Varnishes.

A very large number of samples of enamels and varnishes which

were used on naval aircraft wei-e tested for the Navy Department

with a view to getting the most waterproof and durable coating to apply to wooden parts of airplanes. The net results of these tests seem to indicate than an enamel made of a vehicle of spar varnish and

a pigment containing a considerable quantity of white lead is about

the most satisfactory material available. The specifications were, however, at the Bureau's advice, changed so as to cover physical re- quirements and eliminating definite requirements as to composition

of pigment.

Fireproofing Fiber Board.

Some of the Army hospitals were made of a waterproofed woodfiber board known as Insulite. This construction proved to be a very

great fire hazard and at the request of the Construction Division of

the Army investigations in cooperation with the Heat Division, with

the object of lessening the fire risk, were made. It was fomid that a

solution of water glass was the most successful treatment tried, and

diminished the fire risk somewhat, but the danger from fire will

always be very great with this type of construction. It was recom- mended that, as far as possible, the buildings constructed of this

board be discarded and further use of this building material be discontinued, but that where the buildings could not be vacated all the

interior walls be treated with a spray coat of a solution of water

glass.

Carbon-Tetrachloride Fire-Extinguishing Liquid.

At the request of the War Industries Board and the Quartermaster

General, War Department, experiments were made to find a substi- tute for chloroform as a freezing-point depressant in carbon-tetrachloride fire-extinguishing liquids. It was found that gasoline and

turpentine were both efficient, and the resulting mixtures were fire- extinguishing liquids. It is believed that the use of these depressants

would have resulted in a very great saving in money to the War Department, but the signing of the armistice removed the necessity for

the conservation of chloroform, which was the material previously

specified as a freezing-point depressant, and it is doubtful whether

gasoline and turpentine will be used for this purpose in normal times.

Soap.

A great many samples of soap have been examined for all branches

of the Government service. Additional specifications wei'e prepared

and a ncAv edition of Circular No. 62, containing additional suggested

specifications, was issued. In addition to the specifications given in

the circular, others for shaving cream were prepax^ed for the Purchase, Storage and Traffic Division of the War Department, and the

Bureau is informed unofficially that these have been practically

adopted. In connection with these soap specifications it may be mentioned that shaving cream and liquid soap are materials which the

Bureau does not recommend. It is believed that the liquid soap is not as satisfactory as cake soap and the shaving cream is far more

expensive than other types of shaving soap. There seems to be a demand for these articles ; hence the specifications were prepared.
170 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Linseed Oil. Linseed oil is the most important liquid used in the paint and var- nish industry. It is, therefore, very important to not only have

adequate determinations for purity, but to develop some tests for

quality of oil of undoubted purity, since there is a g-reat diiference

in the value of different lots of linseed oil of undoubted purity. It appears that the presence of foots is the most probable cause of in- feriority in pure linseed oil. The test for foots was developed in this

laboratory some years a^o and has been incorporated in recent specifications. The most important determination in ascertaining the purity of

linseed oil is the iodine number. Unfortunately, there is quite a wide

ran^e in the iodine numbers of pure linseed oils from different parts

of the world. It is, therefore, possible, Avith present methods, to

skillfully adulterate linseed oil of high iodine number with other oils and pass the mixture as pure. The determination of the percentage

of insoluble hexabromides has been frequently recommended as a much more reliable method of determining adulteration than the

iodine number. Unfortunately, all the published methods for the

determination of hexabromide have been faulty in that different

analysts could not get concordant results with them. In the last few

months some important work on this determination has been done in

this laboratory and a tentative method prepared which is being

tested in a number of other laboratories. It is believed that the defects of the older methods have been largely overcome and it is hoped

that this method may prove of great value to the oil analyst.

Miscellaneous.

Among minor problems handled may be mentioned determination

of carbon in pigment, varnish for rifle and hand grenades, tests of

proposed gasoline substitutes, and many other such problems.

6. ENGINEERING RESEARCH AND TESTING.

[Operative efficiency of mechanical appliances, accuracy of engineering instruments, conditions

affecting their effective use, e. g., structure and design as related to durability and efficiency; methods of standardization and tests, standards of performance and fundamental researches on the scientific principles involved in speedometers, pressure gauges, water-current meters, anemometers, tachometers, gasoline and other motors, propellers, and other airplane parts and materials, etc.] MECHANICAL APPLIANCES.

(Investigation and calibration of special mechanical appliances; development of methods and apparatus for standardizing the performance of such appliances ; investigation of operative efBciency of mechanical appliances, such as fire extinguishers, radiator traps, vacuum cleaners, etc.)

Fire-Extinguisher Investigations and Tests. An investigation of hand chemical fire extinguishers and similar

apparatus, undertaken several years ago at the request of the Steamboat-Inspection Service, to determine the merits of devices of this

character intended for use on vessels under its jurisdiction, was con- tinued to include the investigation and test of apparatus offered for

inclusion in its approved list during the past year. A total of 78 fire extingTiishers of various types were tested for the

different Government departments.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 171

The necessity for fire protection of gasoline-driven vehicles, air- planes, and similar risks where low temperatures may be encountered

and other conditions of service pi-eclude the use of older forms of

ajDjDaratus depending on solutions of water, has resulted in the development of a 1-quart liquid-chemical extinguisher using an extinguishing agent consisting principally of carbon tetrachloride. Extinguishers of this type are peculiarly subject to deterioration after

ii short time in service. At tlie request of the Bureau of Construction and Eepair, Navy Department, an investigation was made of

extinguishers of this type to supply data to be used as a basis for

establishing an approved list for the purchase of such devices.

Results of tests conducted for this purpose, including tests after six

months in service, on a number of samples of seven different makes

of extingiiishers showed the majority of the brands tested to be

unsuited for the purpose intended.

To conserve the supply during the period of the war of certain

chemicals used in fire-extinguishing fluids, a series of fire tests was

made, in cooperation with the chemical division, to determine the

effectiveness of substitutes proposed for this purpose.

A member of the section served on a committee of the War Department for the standardization of fire appai'atus.

Comparative Test of Roof Ventilators.

For the equipment of cantonments, hospitals, and other buildings

it was necessar}^ for the Army to purchase large numbers of roof

ventilators. No reliable test data as to the efficiency of the various

types and makes offered for sale were available. At the request of

the Construction Division of the Army, a comparative test of some 33

different 18-inch ventilators was made in the Bureau's wind tunnel.

The comparative efficiency of the different samples in exhausting air

at different wind velocities under identical conditions for each ventilator was determined and a report submitted, in which the various

makes of ventilators were listed, in the order of their merit, for the

guidance of the purchasing officers. Thermostatic Valves for Vacuum Heating Systems.

The investigation of thermostatic radiator valves for vacumn

heating systems for the Office of the Supervising Architect of the

Treasury Department has been continued to include the new devices of this character submitted to that office in connection with

buildings under its control. The efficient and economical operation

of a vacuum heating system is principally dependent on the successful operation of these valves, one of which is connected to each

radiator outlet. Tests are made under different working conditions

to determine whether these devices are successful in keeping the

radiator up to the temperature of the steam supplied, by the con- tinuous removal of air and -water, without permitting the waste

resulting through the escape of uncondensed steam to the return

line. Performance specifications for these valves have been formulated

and are being used by the Treasury and other Government departments in the purchase of equipment of this character.
172 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Miscellaneous Tests of Mechanical Appliances and Equipment.

Numerous miscellaneous tests of mechanical appliances were made

of a more or less extended character, including a series of tests of

relief disk and fusible plugs of high-pressure valves for use on hydrogen cjdinders, and numerous tests of powder containers for

the War Department, tests of reducing valves, steel tubing, flexible metallic hose, relief valves, pipe fittings, etc., for the various Government departments and for private firms.

ENGINEERING INSTRUMENTS.

(Investigation and calibration of engineering instruments, testing of water-current

meters, water meters, liigh and low pressure gauges, speedometers, anemometers, and

tachometers : researches on problems affecting the precision of operation of such instru- ments, including standards of performance.)

Water-Current Meter-Rating Station.

In the development of the water resources of the country in power

development, irrigation, flood prevention, and similar projects an

accurate knowledge of the quantity of water being discharged

through rivers and other open channels is essential. These data

are based on measurements of the velocity of the flowing water made

with current meters. To insure the accuracy of these measurements,

these instruments must be periodically calibrated by towing tests in still water.

Instjillations satisfactory for this purpose, involving the use of

a body of still water and suitable means of propelling the meter

through the water over a range of uniform velocities, together with

instruments for making the necessary observations, are so costly as to be practically limited to Government stations or those at large

universities. The inclosed rating station maintained for this purpose at the Bureau furnishes exceptional facilities for the calibration

and study of these in.struments.

During the past fiscal year a total of 184 current-meter ratings were made for engineers in Government and private service. A series of tests was made of two experimental meters submitted

to the Bureau to determine their suitability for the special purpose

for which they were designed.

Calibration of Engineering Instruments.

During the fiscal year calibrations were made of 201 pressure

and vacuum test gauges, including gauges for the measurement of

pressures up to 30,000 pounds per square inch, 12 tachometers. 10

anemometers, anci a number of miscellaneous tests of instruments,

including indicators, speedometei's, etc. Theory of Measuring Instruments.

The work on this subject discussed in the last annual report has

been continued. The errors commonly known as calibration errors, when they are repeated consistently on successive readings, are not

seriously detrimental in the laboratory use of measuring instruments,

as they can be corrected by simple calculation. Variant errors, on the

contrary, are characterized by failure to repeat their values on re- peated trials, and hence their correction requires special analysis and

treatment. The research which was originally intended to lay down

specific definition and formulation of the variant errors of measuring
KEPOKT OF DIRECTOR OF BUREAU OF STANDARDS. 173

instruments has resulted, in addition, in the development of a method

by AThich the accuracy of determinations made with indicating instruments under certain specified conditions of use and manipulation can

be signally increased, oftentimes fiftyfold. In connection with this

work it was shown that when the conditions surrounding the use of an instrument are subject to control in certain simple respects even

an instrument of crude and inaccurate construction can be made to furnish results of surprisingly accurate character. The researches

forming the experimental basis for this method have been published

in one of the scientific periodicals.

The general principles developed during this investigation have

also resulted in a new method of specifying the performance of a wide range of measuring instruments. Thus it was shown that an

indicating instrument is analogous to a specimen of structural material under stress, in that the occasioning of a deflection, after cyclic

operation has been set up, implies the storing up of a definite amount

of mechanical or other energy in the instrument. The completeness

with which the stored energy is restored when the deflection is again

1-educed to zero may be called the " resilience " of the instrument and

affords a useful measure of the perfection of the instrument as re- gards the consistency or reproducibilit}' of its determinations. This is a result of the fact that all causes which produce variability, or, as it may now be more exacth' termed, variancy, of a sort which is inherent

in the operation of an instrument itself, rather than in its environment, can be correlated with energy dissipation due to the imperfect

' elasticity " or the energy-transformation inefficiency of an instru- ment. The relative magnitudes of this energy loss for instruments

of different types designed for similar purposes afford a criterion of

qualit}^ which is in large measure effective in establishing a definite

basis for selection of an instrument for a given purpose.

These studies have been extended to determine the effect of vibration, or tapping, upon the indications of an instrument, and it was

found possible to establish the general relation of the calibration

obtained under these conditions to that obtained when the instrument

is operated slowly and aperiodically without jarring. A general dis- cussion of the subject of the variance of measuring instruments, with

suggestions for its numerical specification and for its correction in

laboratory practice, was presented before a scientific society by the

Bureau "s expert in this field. Tlie immediate application of these results is to instruments of the

so-called indicating t^'pes. in Avhich the momentary value of the quantity measured is shown (as a pressure gauge or a weighing scale),

rather than to those of the integrating or totalizing type, in which

the summation or total of the values registered up to the time of observation is recorded (as a watt-hour meter or a clock). These in- vestigations have shown the necessity for exact definitions of a number of the terms entering into the specification of instrument per- formance, including accuracy, sensitiveness, passiveness, hysteresis,

lag. resilience, variance, gross precision, and effective or useful precision. A publication is. therefore, being prepared in which all these

terms Avill be clearly set forth and discriminated and a method for the

definite performance rating of instruments will be outlined.
174 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

AERONAUTIC INSTRUMENTS.

(Investigation, testing, and experimental development work on all types of aircraft instruments, including altitude-measuring instruments, rate-of-climb indicators, enginespeed and air-speed indicators, airplane-pressure gauges, gasoline-supply gauges, in- clinometers, banking indicators, turn indicators, bomb sights, and oxygen-control appa- ratus ; also mercurial barometers, weather and surveying aneroids and sphygmomanometers ; development of methods of testing, improvement in design of such instruments, fundamental researches on the physical principles of such instruments, study of their operation in actual service, and determination of corrections required for aircraft-perform- ance tests.) Fundamental Theoretical Work.

There are various instruments which have some physical problems

in common. These have been solved once for all by general mathematical methods, so that the results can be applied to individual

cases as they arise. Problems concerning the flow of fluids which may

be met in the rate-of-climb indicator, in air-speed indicators, and in

oxygen-control apparatus form one such group. Another is the

determination of the combined effect of thermal expansion and

change of elasticity with temperature on instruments con,structed

with springs and diaphragms. A third group deals with the theory

of errors. The results of such investigations are to be found in

Scientific Paper No. 331, A Relation Connecting the Derivatives of

Physical Quantities, and in the technical information circulars re- ferred to below.

Development of Standard Testing Equipment.

Recommendations for standard testing outfits and procedure for

testing altimeters have been furnished at the request of the French

Government, the Canadian Government, the United States Navy, the

Engineer Corps, and the Bureau of Aircraft Production of the

United States Arm5^ In the last instance the first barometers needed were designed and constructed by the Bureau; later orders were

filled commercially on the basis of Bureau of Standards' specifications. The first equipment available for testing oxygen apparatus was also developed by the Bureau and adopted by the Army and

the instrument manufacturers. In addition to such equipment,

which was developed for use in production and inspection work, the

Bureau's own standards, necessarily of a more refined degree of ac- curacy, were further improved during the year. For example, in

the tachometer laboratory a standard test set vras constructed in

which a master tachometer of the liquid type, carefully studied for

temperature errors and lag, is connected to a large motor-driven flywheel to insure steadiness of indications ; and for checking it against

the standard time signals of the Bureau an automatic electro-magnetic clutch was devised. To facilitate testing tachometers in quantity, a multiple-connection drive was made. A large sound-proof

chamber was built for the continuous running of vibration tests with

a minimum of disturbance to the other workers in a seriously over- crowded laboratory. A vacuum chamber with mercury-seal connections for the driving-shaft was constructed for testing certain ta- chometers under altitude conditions. Similar improvements were de- veloped in all the other laboratories of the section. In addition,

methods for testing rate-of-climb indicators and gyroscopic-turn in- dicators were originated during the year.
KEPOET OF DIRECTOR OF BUREAU OF STANDARDS. 175

Construction and Performance Specifications.

On the occasion of a trip to Europe six 3'ears ago a comparison was made between the British, French, and German performance specifications for aneroid barometers and those issued by the Bureau.

Soon after our country entered the war a critical studj' was made

of the British specifications for standard airplane instruments which

had been placed at the disposal of the aeronautic instruments section

of the.Bureau by the Eoyal Flying Corps. At the same time a survey was made of the manufacturing facilities of the country. Thus the

Bureau was already prepared, when called upon by our aviation authorities, to give advice in regard to instrument production and to render expert assistance in preparing specifications. As a result all the instruments adopted as standard hy the Army and Navy were

based directlj^ or indirectly on specifications originating in the

Bureau. During the past year this work has been continued.

Researches on the Errors of Instruments.

Aside from the ordinary errors met in engineering instruments,

such as incorrect calibration, parallax, looseness or friction in the

mechanism, elastic hysteresis, and secular changes, those used on air- craft may be further influenced b}^ the physical conditions peculiar

to aviation, viz, (1) extreme drop of atmospheric pressure, (2) ex- treme change in temperature, (3) vibration, (-i) acceleration or in- clination. For example, a pressure gauge of the Bourdon-tube type

suitable for the engine room may not be accurate when chilled much

below the freezing point ; and a tachometer of the air-viscosity type,

perfectly suitable as an automobile speedometer, may show from 5 to 10 per cent drop in reading at a pressure corresponding to an alti- tude of 25,000 feet. Experiments to determine the characteristic errors of different types of construction for each of the various instruments have been continued and extended during the year. Such

investigations are, perhaps, the most essential feature of the laboratory work of the section, and have been of especial importance during

the war on account of the tendency for the errors to get larger whenever production is speeded up. The results provide a basis for per- formance specifications, for improvements in design or in production

processes, and for estimating the corrections of instruments in use. In the case of altimeters, tachometers, and air-speed indicators the

foregoing data have been supplemented by a statistical analysis of

the results of the routine tests. -Of especial interest during the past

3'ear may be mentioned a comparative study of the various physically

different types of tachometers (chronometric, centrifugal, magnetic,

electric, air-impulse, air-viscosity, and liquid types) ; a determination

of complete corrections for the barographs employed in a flight which

established a world's altitude record; and an experimental study of

Venturi tubes. The latter comprised experiments in a water channel

and in a so-called vacuum wind tunnel, for the observation of effects due to the density, viscositj^, and compressibility of the medium. It

will serve as a starting point later for the computation of altitude

cor'iections for air-speed indicators.

Flight Tests on Airplane Instruments.

Taking with him in an airplane instruments previously studied in

the laboratory, the expert physicist is able to observe and explain
176 EEPOET OP DIKECTOK OF BUREAU OF STANDARDS.

pecularities in their behavior which might pass unnoticed by the

aviator, yet jDrove serious later. Such a flight was made in 1913

before any instruments distinctively designed for airplane use were

yet on the market, and they have been continued at intervals during

the war in cooperation with the aviation authorities. Among those

made during the summer and fall of 1918 was a seaplane flight on a dark night for the demonstration of a projection type of night-altitude indicator; also a trip across the Channel from England to France, at Avhich time a comparison was made between the British

and American compass ; a performance test of an airplane 3 miles up

over the suburbs of Paris; a series of high-altitude flights for the

study of oxygen apparatus; flights for the testing of rate-of-climb

indicators; and flights for the testing of gyroscopic and other in- clinometers.

Instrument Collection.

Extensive additions have recently been made to the collection of

aircraft instruments, including a barograph of exceptional design

by De Giglio, of Turin ; a large French compass with unique mechanical features for use on dirigibles ; and a combination German instrument containing fore-and-aft inclinometer, banking indicator, and

gyroscopic-turn indicator. This collection has been of value for in- struction, investigation, and instrument production, and undoubtedly

is now one of the most complete in the world.

Salvage Methods.

A study has been made of practical methods for repairing defective or damaged instruments, with particular reference to expedients for

readjusting the mechanism so as to give a correct calibration, a more

uniform scale, or a satisfactory degree of temperature compensation.

Such work, especiallj^ on recording instruments, has at times been

done at the Bureau, and the information has proved of value to American manufactui-ers and to our salvage officers and mechanics at flying fields here and in France.

Study of European Instruments and Methods of Testing.

With the authority of the Secretary of War and Secretary' of the

Navy, a representative of the Bureau made a visit to the establishments of the American forces abroad, leaving in August, 1918, and

including some of the principal airdromes, factories, and laboratories

of the allied Governments in England, France, and Italy. This trip

afforded an exchange of the latest technical information and provided

first-hand knowledge of conditions attending the use of aeronautic

instruments in military and naval operations. The reports of the

Bureau's instrument investigations j^roved to be of interest at all points visited, and some of them were immediately duplicated or translated for confidential use. In return, valuable information and

samples of instruments and materials were made available to the

Bureau, and a number of urgent experimental problems were i^ro- posed for the Bureau to take up. As an aid in the study of the

technique of instrument testing, eight typical American instruments

(altimeter, air-speed indicator, compass, thermometer, two pressure

gauges, and two tachometers) which had previously been tested at the

Bureau were taken over and submitted for test at the Koyal Aircraft

Establishment in England, and elsewhere. The success of the trip
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 177 was largely due to the cordial cooperation of Maj. George M. Brett,

<;hief of the airplane instrument and testing division of the American

Air Service in France.

Instrument Instruction for Aviation Officers.

At the request of the Navy Department a school of aeronautic

instruments for navigation officers was conducted by the section in

the fall of 1918. This was an intensive course of three weeks' lecture

iind laboratory work covering the theory and testing of the various

instruments and concluding with a written examination. A some- what similar, though shorter, course had been given the previous

year. Information and photographic material has also been furnished for the use of the Army in instruction courses for military

aviators.

Experimental Development Work.

1. Drawings were made for a recording air-speed indicator with

metallic diaphragms.

2. The problem of ground-speed measurement by dynamical or

other methods not depending on the visibility of the ground has

been investigated and a model illustrating the principle of one such

type has been constructed. Such instruments require stabilization.

3. Detail drawings of a gyro stabilizer for instruments had been

prepared at the time of the armistice and a working model of about

one-fourth size constructed. A bomb sight and double-pivot compass

to go on the stabilizer formed a part of the design. The continuance

of this work Avould be of value for navigation purposes. The doublepivot compass appears to be the only suggestion thus far put forward for theoretically eliminating the "northerly turning error."

4. Inclinometers of the liquid type have been constructed for the

National Advisory Committee for Aeronautics and two new types

of banking indicator developed by the Bureau.

5. By engraving special dials and redesigning the mechanisms cer- tain altimeters submitted by the Army, Navy, and National Advisory Committee for Aeronautics have been converted into instruments more suited for performance tests on aircraft.

6. The conversion of low-altitude into high-altitude barographs

by the Bureau's method has been continued at the request of the

Army.

7. A study has been made of the possibilities of different principles

for recording airplane vibrations, including the piezoelectric effect,

and several trial vibrometers constructed. In this connection a new

type of vibrating stand has been developed which has greater adjustability than previous forms, and which does not subject the

driving motor itself to the vibrations; also a model has been constructed illustrating the theory of so designing the movable parts

of instrument mechanism as to balance them against the effect of

sudden angular accelerations, such as chiefly compose the instrumentboard vibrations of an airplane.

8. A new feature in oxygen-control instruments, which would

avoid the main source of temperature error, was developed.

9. A preliminaiy model of an improved centrifugal tachometer

has been constructed and found promising in several particulars.

10. A start has been made on the experimental woi"k in connection

142289—19 12
178 KEPORT OF DIRECTOK OF BUREAU OF STANDARDS.

with the construction of a large open-scale altimeter at the request

of the National Advisory Committee for Aeronautics. Such an in- strument, though not a commercial proposition, is greatly needed in

aircraft-performance tests. In connection with the work of the

altimeter laboratory, a study has been made of the possibility of

combining thermometric and pressure elements into a single mechanism. One such combination would afford a true altitude meter,

whereas the existing altimeters assume a fixed temperature for the

atmosphere and require the computation of large corrections. Another combination mechanism would give a direct-reading density

meter. Three methods also have been proposed for avoiding the

evil of elastic fatigue in altimeters. One consists in providing an

auxiliary instrument with a very open scale reading only to 1,000

feet, above which point it is automatically shut off from the atmosphere, and thus protected from the strain which causes fatigue.

A second consists in making the steel mainspring of the altimeter

so much stiffer than the diaphragms that the latter, however poor

the material may be, can only contribute a small proportion of the

observed result; this method is made possible as a result of experiments which have shown that the steel springs of good commerical

aneroids have onlj^ an insignificant amount of fatigue in comparison,

with the diaphragms. A third method is the obvious, but less immediate, one of developing eventually better materials or designs

for the diaphragms. This is described under (14) below.

11. A rate-of-climb indicator has been developed, using thin metallic diaphragms in place of the usual liquid manometer. The latter- has the disadvantage that the readings are seriously affected by incli- nation and acceleration. A comparative test in airplane flight was in

favor of the Bureau's instrument, except for the time lag, whick

should be further in's^estigated. 12. In addition to the electric-spark-recording process, other ink: substitutes have been studied and a successful radium method developed. In this connection plans have been made also for the use of the moving-picture camera for securing a record of the instrument

readings during an airplane-performance test. 13. Altimeter chains have been studied by a special life-testing device, and the supei-iority of gold chains thus far indicated.

14. Diaphragms have been spun in the instrimient-development

shop of the section and given a mechanical aging treatment. This

process has been found more effective than heat treatment in reducing

the elastic feature of unseasoned material' The elastic properties of

a large number of diaphragms, made from alloys selected in consultation with the metallurgy division, have been measured in the hope

of producing a material or a design superior to those in cormnercial

use. This work has been done at the request of the National Advisory

Committee for Aeronautics, and is to be continued.

Testing of Aeronautic Instruments.

During the past 12 months 578 tests have been made on instruments submitted from outside. The value of these tests on the basis

of the Bureau's fee schedule would aggregate about $10,000. They

were distributed as follows: 148 altimeters, 63 barographs, 50 stato- scopes, 6 mercurial barometers, 74 air-speed indicators, 59 sets of

oxygen apparatus, 134 tachometers, 18 pressure gauges, and 26 spe-
REPORT OF DIEECTOR OF BUREAU OF STAI7DARDS. 179

cial instruments or appliances. The latter comprised 2 gasolinedepth gauges, 2 aerographs, 8 reducing valyes, 5 aneroid stacks, 2

unit sights, 2 inclinometers, 1 electromagnetic rate-of-climb indicator,

1 night altitude indicator, 2 bomb sight speed regulators, and 1 gyroscopic-turn indicator. Practicallj- all the tests included endurance

runs or some other feature making them more complete than the

factory-inspection tests. Many of them were in the nature of short

investigations to determine the suitability of new types of instruments for production. In addition, 95 thermometers and 9 compasses were tested by the heat division and the electrical division of

the Bureau. The list does not include tests made on instalments developed by the Bureau, nor upon instruments submitted solely for

the collection.

Technical Information Circulars.

Tlie series of aeronautic-instruments circulars for confidential distribution begun the previous year has b:en continued. These documents are duplicated for temporary use and serve to make the results of the Bureau's investigations immediateh^ available to authorized

persons. The following were issued during the year : Spinning-Top

Inclinometers ; Historical Notes on Aneroid Barometers ; Two Aneroids Tested in England, France, German}', and the United

States; Methods for Testing Aneroid Barometers; Testing Methods for Airplane Tachometers; Air-Speed Indicators; Statoscopes and Climbing Indicators ; List of American Instrument Manufacturers ; High-Altitude Barographs ; Report on a Group of Britisli

Instruments; Report on a Group of Danish Instruments; Methods

for Testing Air-Speed Indicators; Gasoline-Level Gauges; Airplane

Pressure Gauges ; Instruments Tested January 1 to June 30, 1918

;

Inclinometers; Airplane Tachometers: The Theorj' of Dimensions

with Applications to Instrument A¥ork; A Theory of Irreversible

Time Effects, with Applications to Instrument Work; Mechanical

Design of Anei'oid Barometers ; Temperatui'e Compensation of Aneroid Barometers; A Night Altitude Indicator; A Proposed Plan for

Bomb Sighting; Airplane Thermometers (contributed by the heat

division of the Bureau) ; Report on a Group of American Instru- ments Tested Abroad. Owing to the limitations of the Bureau's

photographic service, it has not been found possible to keep up with

the demand for this material, even though it has not yet been publicly announced as available.

Correspondence and Conferences.

Much information and advice has also been given out in reply to

official correspondence and in response to verbal requests. A considerable part of this-consisted in the examination of inventions in

connection with aeronautic instruments and other appliances submitted by the General Staff of the Army and by the National Advisor}' Committee for Aeronautics. Members of the section individually conversant with some particular branch of ph5'sics, as

elasticity, capillarity, viscosity, high-pressure measurements, or the

theory of errors, have frequently been called upon for conferences

with visitors or for cooperation with some other section of the

Bureau. During the summer of 1918 the section was visited practically every day by production officials of the Army or Navy to follow

the results of investigations or discuss specifications, with occasional
180 KEPOKT OF DIRECTOR OF BUREAU OF STANDARDS.

visits also from foreign delegations. And in accordance with the

Bureau's iDolic}- of cooperation with other organizations the chief

of the section has served, by request, on the subcommittee for lubrication of the research committee of the American Society of Mechanical Engineers; on the airplane-instruments committee of the Inter- national Aircraft Standards Board; and on the aerodynamics committee of the National Advisory Committee for Aeronautics.

Cooperation with American Manufacturers.

The Bureau has been of assistance in building up an American

instrument industry not only by carrying out fundamental researches

which no single manufacturer could undertake but also by con- tinuously helping manufacturers to improve their product in matters of detail. This has been accomplished by frequent informal

conferences at the Bureau and in the factories, and at times also b}'

telegraphic reports. At one time a certain manufacturer complained

that the Bureau's performance specifications for barographs, on which his contract was based, Avere too strict in their requirement for

temperature compensation and wished to have instruments accepted

which were four or five times over the limit. Before reconsidering

any tolerances the Bureau's expert was sent to the factory with

scientific suggestions for diminishing the error in question. Less

than two months later this manxifacturer was successfully producing

instruments averaging onh' one-half the temperature error permitted

by the specifications. This experience is merely typical of many

other instances.

Cooperation v/ith American Physical Society.

At the request of the society this section contributed several papers

by title at the spring meeting on war problems, three of which were

presented in full, dealing, respectivel}-, with general investigations

of air-speed indicators, tachometers, and altitude instruments. A

large exhibit of instruments and testing appliances was shown at the same time as a part of the society's exhibition. This included

tachometers, gyroscopic instruments, a rate-of-climb indicator, and

other devices in actual oDeration.

Cooperation with National Advisory Committee for Aeronautics.

This section has cooperated continuously with the Advisory Committee, avoiding duplication of Government facilities by serving

in effect as the instrument laboratory of the committee. A considerable group of aeronautic instruments, together with gi'aphical

charts, also a whirling table of banking indicators, a vibration stand,

and a chain-testing outfit, all kept in motion by electrical connections, were contributed to the exhibit of the Advisory Committee

at the Manufacturers' Aircraft Exposition in New York.

Future Development of Aeronautic Instruments Work.

The instruments of an airplane or dirigible are its sense organs.

It can fly without them, but only blindly. When one considers the ever present danger of a crash in the fog, together with the high

cost of the large aircraft now coming into use, any reasonable ex- penditure for improving the reliability of the instruments justifies

itself at once, even without taking into account the value of human

life. A further need for instrument investigation comes from the
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 181

fact that those types of instruments which are adapted for measuring aircraft performance underlie the whole future development of

aeronautical engineering, since this all goes back in the end to questions of measurement. For these two reasons alone no financial

investment in aeronautics of any moderate magnitude could be more productive than one devoted to the advancement of instrument work.

AERODYNAMICS.

(Fundamental data of aerodynamic physics as applied to the study of the resistance

of air to the motion of bodies, including the magnitude, direction, and point of application of the resultant force, and its relation to the relative speed ; study of the aero- dynamical properties of airplane-wing models, stability of model airplanes, efficiency of propellers and wind motors, characteristics of air bombs, and the testing of airplane

equipment and other apparatus functioning in an air stream.) Wind-Tunnel Investigations.

The Bureau now has in operation two wind tunnels of the open

type, the larger of which is well adapted for the testing of model

airplanes and wing sections, while the other, and smaller one, is used in the testing of airplane equipment in which the attainment of

high air speeds is necessary. The 54-inch octagonal tunnel is housed in a room 79 feet long,

29 feet wide, and 18 feet high, and is equipped w^ith two weighing

balances. One balance is of heavy construction and is designed for

the measurement of lift and drag forces on heavy models, such as

air bombs and engine radiator sections. The second balance is much

more sensitive, and is used primarily in the determination of the

characteristics of aerofoils and airplane models. From these models

test predictions may be made of the behavior in flight of the full- scale machine. In this tunnel air speeds ranging from 5 to 90 miles

per hour are obtainable.

To keep pace with modern aircraft developments, the Bureau

began in October, 1918, the construction of a high-speed wind tunnel. This tunnel, which was completed and in operation in April,

1919, is of the Venturi type, 36 inches in diameter at the throat or working portion, and is constructed entirely of wood, the tunnel

proper being built up of cypress-wood segments. The tunnel was

designed for a maximum wind speed of 150 miles per hour at an

expenditure of about 100 electrical horsepower. In subsequent tests, however, air speeds of 180 miles per hour were obtained with an

expenditure of 120 electrical horsepower. The wind stream is maintained by a tractor propeller, 7 feet in diameter, connected

directly to a 125 -horsepower direct-current motor. The tunnel is housed in a room 106 feet long, 27 feet wide, and 12 feet high.

Besides work of a distinctly military nature, such as studies of

the characteristics of aircraft bombs, time constants of arming

vanes, methods of driving aircraft reconnoissance cameras, and

calibration of variable-pitch propellers for wireless sets, tests have

been made on a number of monoplane, biplane, and triplane models

and on a large number of wing sections. These latter included tests on a series of ribbed aerofoils, a series of German wing sections, and

a series of aerofoils in connection with the desig-n of an automatic

variable camber wing.

Cooperation has been afforded aircraft designers and manufacturers in the calibration of various types of air-speed indicators
182 KEPORT OF DIRECTOE OF BUREAU OF STANDARDS.

and in the determination of the characteristics of aerofoils and air- plane models.

PHYSICAL OCEANOGRAPHIC INSTRUMENTS.

(Assistance in design and construction of physical oceanograpbic instruments.) In cooperation with the scientific work of the International Board

on Ice ObserA-ation. the facilities of the Bureau haA'e been extended

for the design and constniction of new oceanographic instruments.

A convenient, accurate instrument to measure the saline content of

sea water has been designed and constructed and successfully used on shipboard. Any instrument to be used at sea must be simple,

convenient, easily operated, and rapid.

An investigation is now in progress to determine the relative

accuracies of the several methods of measuring sea-water salinity.

Samples of sea water have been forwarded to the Bureau and

measureinents of these have been made by the chemical, electrical,

and density methods, and the results obtained are to be compared

with a niethod of hydrostatic weigliing. This work is being done in

cooperation with the Bureau of Fisheries.

7. STRUCTURAL, MISCELLANEOUS, AND ENGINEERING

MATERIALS.

[Invstigation of properties, use, fabrication, and design of structural, miscellaneous, and en- gineering materials; development of specifications covering the use of such materials; im- provement of processes of manufacture ; improving present and developing new methods of testing; development of testing apparatus.] METALS.

(Development of airplane design, including structures and appurtenances and discovery

of suitable materials for construction purposes, especially metal construction ; investigation of processes for kiln-drying of timber ; Investigation by means of the strain-gauge of stnictures under load ; welding research for ship construction ; calibration of testing machines and extensometers ; standardization of hardness testing with various machines ; de- termination of the physical properties of metals, woods, molded materials, and rope.)

Variable Camber Airplane Wing.

One of the most important investigations carried on by this sec- tion during the past year is that of the variable-camber wing, so named because of its change from stream line to lifting shape with

a change in flying speeds. This work was carried on in cooperation

Avith the National Advisory Committee for Aeronautics, who suggested the problem.

With the present form of airplane, it is found that the landing

speed is about one-half the maximum attained in flight. If the

speed in flight is great, Avhich is particularly the case for military

work, the landing speed becomes almost prohibitive.

This Aving has been designed so as to assume the cambered or lift- ing form when the airplane is traveling at low speeds. This change

in form is due to the pressure of the air upon the lower surface of

the wing. The pressure is caused by the forward motion of the

machine with the ])lanes tipped from the horizontal so that their

leading edges are about 6 inches above their trailing edges.

The shape of the cambered wings is such that their lifting ca- pacity is great, and their minimum speed low. As the speed in-
KEPOKT OF DIRECTOR OF BUREAU OF STANDARDS. 183

creases after a flight is begun, the wings are gradually changed so that the leading edge is brought nearly at the same level as the

trailing edge. The pressure of the air upon the variable-camber

wing then becomes equal on the upper and lower surfaces, and the

wing assumes a stream-line shape which offers only about one-quarter the air resistance of the cambered wing. Any decrease in re- sistance causes a corresponding increase in the speed of the airplane

if the engine thrust is constant, which is practically the case. In order to determine the behavior of the variable-camber wings

when combined with the usual form of Aving in both biplane and

triplane combinations, models were tested in the wind tunnel at this Bureau. The results of an extended series of experiments

showed that their behavior was entirely satisfactory.

This problem has been carried as far as possible in the laboratory,

and shows promise of operating satisfactorily in actual use. The

work has progressed to the stage where it should be tried in actual

airplane construction, first to be sandloaded to prove that its behavior under load is satisfactory, and that the structure possesses the required strength. A variable-camber airplane should then be

used to demonstrate its value in actual flight. If expectations are

fulfilled, there is no doubt it will prove a great stride forward in

airplane progress. Test of 150-Ton Floating Crane for the Navy.

At the request of the Bureau of Yards and Docks, Navy Department, strain-gauge measurements were taken on some of the important members of a 150-ton (336,000 pounds) revolving floating crane

built for use in the navy yard at Norfolk, Va.

This test was made to determine the distribution of stress among

the various members of the crane while under load and to obtain

a more complete knowledge of the actual amount of stresses in some

of the members of this statically indeterminate structure. This crane represents the most advanced type of revolving float- ing crane of large capacity. The jib is a tapering Pratt truss, hinged

to the superstructure in the loAver chord and connected to the luf^g

screws at the upper chord by suitable links. The length of the links

and the location of the luffing screAvs are such that a nearly direct

pull is exerted on the upper chord of the jib for all positions. The

superstructure, exclusive of the jib, consists of two subdivided tri- angular trusses rigidly connected by cross bracing. The entire re- volving load is transmitted by the triangular trusses to the pontoon

through a pintle, the pintle being an inverted pyramidal shaped

member built up on four posts, which transmits its load at the apex

to a thrust bearing on the deck of the pontoon. The pintle is supported laterally on a tower consisting of six legs arranged in the

form of a hexagon, the legs of the tower being carried through the

deck to the framing of the pontoon. The tower is framed into the

hull in such a manner as to make the pontoon act as a large girder

in resisting the forces induced by a crane load. The pintle rotating

AA'ithin the tower makes it possible to revolve the superstructure with

the live load to any position.

Readings were taken at various points of the deck to determine

the magnitude and, if possible, the position of the maximum stress in the upper-deck plate ; on the tower members, to determine whether
184 KEPOKT OF DIRECTOR OF BUREAU OF, STANDARDS.

the tower acted as a unit ; around the manhole in the tower legs, to find

the effect of such an opening; on the pintle, to determine the magnitude of the stress in these members ; and on various jnembers of the

superstructure, to determine the manner in which the loads were

carried down to the pintle.

Gauge lines wei-e placed on two opposite sides of every member

tested, and, where possible, on all four sides. Gauge lines were laid

out on the deck of the pontoon for the purpose of determining the

amount of stress developed in the plates of the pontoon deck and to check the computed locations of the maximum bending moments.

Strain-gauge readings were taken with a 10-inch Berry strain

gauge, it being possible to read the change of length between the

points of the instruments directly to the nearest 0.0002 inch, and by

estimation to 0.00002 inch.

The material used for loading the crane consisted chiefly of armor

plate and scrap iron of known weight. The loading was so arranged

that each member on which measurements were taken was subjected

to the maximum possible range of stress. The strain-gauge work done on this structure showed that all stresses on the various members were within safe limits. Tests of Motor-Truck Wheels.

In designing class. B military truck it was found desirable to develop a metal wheel having the good qualities of all the wheels on the

market. As there was not sufficient time to make service tests, this

section conducted radial-compression and side-thrust tests upon cast

steel, pressed steel, wrought iron, and wood wheels made by various,

manufacturers. From the data obtained from these tests a cast-steel wheel known as the " composite " wheel was designed. This type of

wheel proved satisfactory in test and was, therefore, adopted for use on the class B truck.

Twenty-one wheels wex'e tested. The deformations of the wheels

under the radial-compression tests were recorded for four points on

the rim spaced 90° apart. Similar data were obtained from the sidethrust or skid tests. From these test data, the limit of proportionality, ultimate

strength, rate of deformation, and elastic resilience were found for

each wheel.

Strain-gauge measurements were made upon one cast-steel wheel

to determine the stress distribution.

A stress analysis of this kind should prove valuable in the design

of wheels, and the many inquiries from wheel manufacturers for

these data show their interest in such work.

Tests of Electric Welds.

The urgent need for ships to transport our men and material to Europe during the recent war with Germany made it necessary to adopt every means of securing maximum output from the shipyards

of this country. The "fabricated" ship, constructed from plate

material on which all cutting and drilling had been completed at remote mills before shipment to the jSLvd, saved time at the shipyard under the conditions existing during the war. Another radical suggestion, which was never used to the extent which its merits warranted, was the electric welding of the frames

and plates of the hull instead of riveting. Autogenous or fusion
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 185

welding lias been in use for many years. Most of this work has been

done by the use of the gas torch, to which oxygen and acetylene are

supj)lied. The weld is formed by fusing together the adjoining

edges of the pieces of metal. Material is sometimes added at the same

time from a metal rod.

In the electric-arc welding process, the fusion of the metal is ef- fected by an electric arc formed between a metal rod (or electrode)

and the pieces to be joined. Metal from the rod is deposited in the

weld.

Due to the prohibitive cost of the gases required for oxyacetylene

welding, its use upon ship hulls was greatly restricted and the possibility of using electric welding to replace riveting was carefully

considered.

The Welding Eesearch Committee of the Emergency Fleet Corporation was formed to study the matter carefully and conduct any

needed investigations. This Bureau had representatives on the committee and performed much of the laboratory work for determining

the properties of the welds, particularly the strength.

In order to obtain definite information upon welds which were

being made commercially, a large number of pieces of one-half inch

steel plate were welded at different shops, using all available types

of apparatus. These were known as the Wirt-Jones tests and at- tracted a great deal of attention from engineers and shipbuilders.

The welding data included a mark by which the operator could be

identified, the position in which the weld was made, the type of weld,

and the rate of welding. The type of electrode used with the diameter and manufacturer, as well as the arc and open-circuit voltage

and the amperage, w^ere recorded for each test weld.

These data were obtained in the shops where the welds were made.

The specimens were machined there and elsewhere.

The physical tests were all made at the Bureau of Standards and

consisted of tensile, torsional, fatigue, and cold-bending tests. It was found that all of these, except the fatigue tests, which gave

erratic results, were consistent. A specimen showing high strength

in the tensile test showed high strength in the torsional also. Those

specimens showing relatively high ductility in the tensile tests showed

equally well in the cold-bend tests. The fatigue tests were made in

three Upton-Lewis machines and by three different engineers. Unfortunately, the results do not appear as consistent as could be

wished. Many fatigue experiments should be conducted if reliable

data are to be obtained upon this important property of welds. It

is believed by many engineers that the failure of welds in service is usually by fatigue, and that this property of welds is relatively more

important than the fatigue resistance of the material in which the

weld is made.

In an extension of the experimental work to determine the fatigue

resistance of welded joints such as would be actually used in ship

• construction large specimens were made from plates one-half inch

thick, 8 inches wide, and 40 inches long.

A fatigue machine driven by a 15-horsepower electric motor was

designed and built to subject these specimens to repeated bending

stresses with provision not only for recording the number of cycles

of stress required to cause failure, but also for making an auto-
186 KEPORT OF DIRECTOK OF BUREAU OF STANDARDS.

graphic record of the stress produced in the welded material for each

application of load.

The total number of specimens in this series was over 200, and the

testing work required most of the time of two engineers for nearly

a year. In addition to the Wirt-Jones tests, this Bureau was at one time

making progress reports to the welding committee on 14 investigations planned to give information upon some of the many prohlems constantly arising in connection with welding work. The

number of specimens involved in these investigations varied from 5 to 42. Due to the satisfactory results obtained from these tests, it was

decided that the electric-arc welding process was suitable for ship

construction, and the committee formally recommended to the Emergency Fleet Corporation that a merchant ship be designed to utilize welding wherever it could be employed to advantage, and that the

ship be completed as soon as possible.

The signing of the armistice took place before much progress was

made, but some commercial shipyards are now energetically preparing to construct ships in which nearly all the frames and plates for

the hull are welded into place.

It is estimated that the cost of welding will approximately equal

the cost of riveting plates and frames after they have been " laid

off " and the rivet holes punched. For welding, however, all this pre- liminary woi^k is unnecessary, and the plates and angles do not need

to be as accurately cut to dimensions. The saving, if welding is used, is therefore very large and it is chiefly a saving in labor cost, which imder present conditions constitutes a large portion of the

total cost. One result of these extensive investigations was the important conclusion that the best physical properties were obtained from those

specimens welded with the highest current density in the electrode. Apparently, under this condition, thorough fusion occurred in the

weld.

The importance of this discovery, which is generally accepted at present, is very great. The fact that little properly conducted investigational work has been done upon welding processes, and the many

possible lines for improvement, leads to the conclusion that such work

offers great ]3ossibilities if properly carried out. The American Welding Society, an outgrowth of the welding committee, has been formed to encourage welding-research work by co- ordinating the efforts of industrial, educational, and governmental

laboratories. This Bureau is assisting the work of this society in so far as possible.

Tensiometer,

It is a well-known fact that it is very desirable to know the load

that is placed upon the wires and cables of airplanes.

Heretofore no instrument has been available for measuring these

stresses with sufficient accuracy. With this purpose in mind an instrument was designed by one of the members of the Bureau's

staff and constructed in the Bureau shop. It consists chiefly of two

supports at a fixed distance apart and a moving plunger located

midway between them, by means of which the wire may be deflected
KEPORT OF DIRECTOR OF BUREAU OP STANDARDS. 187

a definite amount of 0.1 inch. The load on the wire is measured by

an Ames dial, which measures the compression of a calibrated spring

against which the plunger operates.

This instrument, which gives accurate readings on wires of small

diameters, requires the use of calibration curves when heavy wire,

cable, or stream-line sections are used. Two sizes of this instrument

have been supplied at the instance of the Bureau of Construction

and Eepair, Xavy Department, the smaller one being made for wires

from 0.05 to 0.25 inch -in diameter, and the large one for wires and

cables from one-fourth to three-eighths of an inch in diameter.

These two sizes of tensiometer were calibrated on 10 sizes of cables

ranging from one thirty-second to three-eighths of an inch in diameter; on four sizes of hard-drawn wire and on four sizes of streamline wire, and were found to give very satisfactory results. The instrument is sufficiently accurate, being capable of indicating

the actual load within 1 per cent of the actual load on the wire, if it

is under a load of more than 1,000 pounds. It is simple in construction as well as quickly and easily operated.

Over a hundred of these instruments have been built and are beingused by the Navy Department.

Investigation of Wire Rope.

The results of an investigation on 275 wire ropes have been published in Technologic Paper No. 121. The ropes ranged in diameter

from one-fourth to 3J inches. Five important classes were tested

:

(1) Very flexible rope of 6 strands, 42 wires each, used for boat

tillers and elevator hand lines; (2) ropes for guys of derricks, stacks,

and haulage purposes having 6 strands, 7 wires each; (3) (4) trans- mission rope of plow and crucible cast steel having 6 strands, 19

wires each; (5) extra-flexible plow-steel rope of 8 strands, 19 wires

each. The laws of construction and behaviors of the specimens have

been reduced to empirical equations. The results of the tests are compared with the strengths called for in well-known specifications.

A further investigation has been carried out to determine the relative strengths of hoisting and transmission wire rope when used in

connection with sheaves, as in the case of derricks and cranes. This

investigation was made possible through the aid of a large manufacturing corporation supplying the necessary materials. The ropes

varied from five-eighths to 1| inches in diameter and were tested

when bent over sheaves of diameters 10, 14. and 18 inches. An abstract of the results was published in the Engineering and Mining

Journal, April 26, 1919. It was shown that the strength on 18-inch

sheaves varied from 96 per cent of the strength in direct tension for

five-eighths-inch ropes to 87 per cent for the ll-inch ropes. The cor- responding values for 14-inch sheaves were 95 and 82 per cent, and

on 10-inch sheaves 84 and 77 per cent. The mean departures from

this range were about 1 per cent. The above values should be reduced

about 10 per cent when the strengths are expressed in terms of the

aggregate strengths of the wires in a specimen.

The cables generally fractured at the point of tangency with

sheaves. Cracks developed in several sheaves, showing that there were opportunities for improvements in design, but as a whole the

strength of the sheave system was limited bv the individual strengths

of the wire rope, which as a function of the diameters was expressed

by the formula /S'= 83,000 d}.
188 EEPOKT OF DIRECTOR OF BUREAU OF STANDARDS,

Oxyacetylene.

A carefully planned series of tests intended to demonstrate the

economy and efficiency of oxyacetylene welding and cutting apparatus is being made. Apparatus from most of the leading manufacturers in this line has been received for test. The tests are planned to show the conditions under which backfiring occurs, the characteristics of regulators under varying tank

pressures, the economy of the apparatus in welding and cutting operations on material of various thickness, and in some measure the

durability and the ease with which repairs can be made in service. Machetes.

A number of machetes, representative of material intended for

purchase by the Panama Canal, were submitted for test 'to determine their suitability for use in cutting and clearing away brush and

undergrowth of the Panama Canal district. These machetes were subjected to a series of mechanical tests, such

as Brinell hardness and cold bend, to determine the variations in

properties which exist in the commercial product ; that is, the hardness along and across the blade and its comparative toughness as in- dicated by bending. Chemical analysis and micrographic examinations were also made. These tests gave comparisons between various

blades of one manufacture, indicating the constancy of his product

as well as the difference between blades of different manufacturers.

While certain of the blades submitted proved unsatisfactory, in. that they were brittle, most of the others passed all tests and appai'eutly are satisfactory for the work intended, Avith the exception

possibly of the Brinell-hardness number. None of the blades reached

the desired hardness number. There was also some variation in

carbon content, but the effects of this latter was generally made up

by improved heat treatment. Such tests might well be applied to a large number of cutting

instruments.

Brinell Hardness Table.

A Brinell-hardness numeral table, correct generally to the second

decimal place, has been compiled and lithographed, which gives the

Brinell-hardness numeral for each hundredth of a millimeter of

diameter of indentation from 2 to 6.94 millimeters and for pressures

of 500 and 3,000 kilograms.

Copies of this table will be sent gratis upon application.

Piston Rods.

A number of tests were made on 8-inch recoil piston rods for 12- inch Barbette carriages at the instance of the Ordnance Department

of the Army.

The rods were submitted for. a tensile-proof load of twice the

working load for the purpose of insuring the quality of the material

entering into the forging. All of the rods which were tested in this manner proved entirely satisfactory.

Nonscatterable Glass.

This protective glass, suitable for aviators' goggles and airplane

wind shields, consists of a sheet of celluloid " welded " to one side of

the glass, the intention being to place the celluloid on the side toward

the person to be protected.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS, 189

An interesting series of tests—that is, firing, to determine the effect of small-arm j)rojectiles ; cross bend, loading as a simple beam to determine its strength ; and impact, to find the effect produced by

the striking of a pendulum weight—were made on this glass to determine its value as a protective screen, and to note the effect the

celluloid coating has on the strength of the glass.

In the firing tests it was found that the dangerous scattering of

large pieces of glass was entirely prevented. The celluloid coating

Avas easily scratched or marred. In the impact tests the plain glass was broken into many small pieces, while the treated samples cracked,

but the pieces were held together by the celluloid. In the cross-bend

tests the treated glass of a given kind and thickness was about 1.5 per cent weaker than the plain glass when the celluloid-coated side was in compression, and about 40 per cent stronger when the cellu- loid was in tension.

Metal Airplane Construction.

Xo experimental work has been done during the past year upon

the use of metal to replace wood in airplane construction, such as was carried on the previous year by this Bureau in cooperation with

the Empire Art Metal Co. and the Airplane Engineering Division of

the Bureau of Aircraft Production. Immediate interest in the subject decreased upon the signing of the armistice, but the future of

metal construction appears promising, especially as the need for a

fire-resisting airplane becomes more generally understood.

To avoid the difficulty which has been found in designing sheetmetal parts so as to secure sufficient compressive strength—as, for

example, in the flange of a beam or spar—one engineer has devoted

much time and study to the use of steel tubes. A single metal tube

has much less strength for its weight than a beam designed to concentrate most of the material in the flanges which are subjected to the

Iiigher stresses. The tubular design uses several small cold-drawn steel tubes for

the flanges which are connected by diagonal latticing of tubes of

smaller diameter. The de,sign is very flexible in that the number of

tubes used may be varied in the length of a single beam to meet the

strength requirements. It is also possible to join tubes by inserting

a snugh^ fitting tube of smaller diameter into another for a distance

which will give satisfactory strength. Methods of fastening the two

tubes together readily present themselves. • It is believed that encouragement and assistance given to metal

construction by this Bureau is now about to result in material improvements in that field which will come into general use. Semisteel Shells. At the request of the Ordnance Department of the Army, a number of 15o-millimeter shells of semisteel have been subjected to a thorough examination as to mechanical, chemical, and metallurgical

properties. In order to determine the probable stresses set up in

shells that showed excessive expansion after firing, tests were made

to determine the true elastic limit; that is, that stress at which

permanent deformation is first produced. Further, a study was made

of the variation in the chemical and mechanical properties throughout the length of the shell. It was found that the strength of the
190 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

material, its hardness, and the percentage of combined carbon decreased consistently from the thin section at the nose of the shell to the heavy fuse sections. This agrees with what might be expected

from such a material as semisteel, a modified cast iron.

The entire series of tests on semisteel shells also indicate that at present there is considerable variation in the mechanical properties

and chemical composition of the so-called semisteel.

Bronze.

Over 300 samples of bronze have been submitted by Division VIII

for tests. Among the ditferent varieties were the following

Cast, both heat-treated and not heat-treated, phosphor, Government, nickel, and welded bronze.

Tensile tests were made on these specimens in order to determine

their proportional limit, ultimate strength, elongation, reduction of

area, and modulus of elasticity. Stress diagrams were drawn for

each specimen.

Calibration of Testing Machines.

During the past year considerable work has been done upon the

calibration of testing machines.

Four testing machines having a capacity of 200, 4,000, 80,000,

and 150,000 pounds, respectively, and one having a capacity of 100,000

pounds, were tested at the navy yard, Washington, D. C, by means

of the Emery proving levers. Other machines and instruments calibrated by this section are the

following : Dynamometers, both tractor and recording ; tension meter

(Crowell) ; tensiometer (Larson) ; horizontal Scott testing machine;

10,000 and 50,000 pound Riehle testing machines ; 20,000-pound Olsen

testing machines ; 2 and 8 inch Berry strain gauges ; Olsen McAdam

impact-testing machines ; Upton-Lewis testing machines.

Circulars of information.

The folloAving is a brief summary of a few of the letter circulars

prepared by Division VII-1.

Letter Circular VII-1-1, "Mechanical Properties of Materials."

A great deal of time was spent in the preparation of this most valuable and interesting paper, which contains the best available data on

the strengths and related properties of metals, alloys, and certain

nonferrous materials. Among the materials treated are iron, carbon

steels, alloy steels ; wire and wire rope ; semisteel ; aluminum, copper,

and miscellaneous metals and their alloj^s ; rope, rubber, leather, and

wood. This circular also includes definitions of the properties

treated and references to sources. These data were originally compiled for the Smithsonian Physical Tables, from technical literature,

the Bureau's test reports, and other reliable sources. There has been such a great demand for this paper that it has

been prepared for publication as a Bureau circular. Letter Circular VII-1-2, " Definitions of Mechanical Properties."

This gives definitions which govern the more commonly confused

terms for properties determined from mechanical tests of materials

shown in the tables of Letter Circular VII-1-1, such as P-limit,

elastic limit, yield point, ultimate strength, modulus of rupture,

modulus of elasticity, Brinell-hardness numeral, Shote scleroscope

hardness, and Erichsen value.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 191

Letter Circular VII-1-4, " Standard Test Specimens for Mechanical Properties of Metals." This circular gives a detailed description

and a dimensioned drawing of the specimens to be submitted for

the determination of different mechanical properties, such as tension,

compression, torsion, fatigue, or impact stre"ngth. Letter Circular VII-1-5, " Fees for Mechanical Tests." This cir- cular gives the fees charged by this Bureau for conducting tests for

the determination of mechanical properties, such as those mentioned in Letter Circular VII-1-4 above. Letter Circular VII-1-6, " Parker Variable-Camber Wing." This

gives a very good description of a new type of airplane rib recently

designed and built at this Bureau, including tables of test results on

same. These circulars have been prepared in mimeographed form, and

copies will be sent gratis upon application.

Publications.

The following is a brief outline of the publications which were

prepared by this section

:

Physical Properties of Materials, by H. A. Anderson, assistant

engineer physicist : A compilation from the best available sources of

data on the various physical properties of metals and other nonferrous materials, with definitions of the properties treated and

references to sources. Test of 150-Ton Floating Crane, by Louis J. Larson and Eichard

L. Templin, assistant engineer physicists : A description of the methods employed, with analysis and discussion of the results obtained

from the strain-gauge measurements taken on many different portions of the crane. Strength of Spruce Struts, by Prof. James E. Boyd : Experimental

data on the strength of spruce airplane struts of uniform cross

section, together with the development of the mathematical theory

for the design of plain and tapered struts. The following papers will soon be in the hands of the Publication

Committee, as the manuscript is practically complete at this time:

Physical Tests of Motor-Truck Wheels, by Charles P. Hoffman,

assistant engineer physicist: Experimental data on radial compression and skid tests of cast-steel, pressed-steel, wrought-iron, and

wood wheels.

Strain-Gauge Measurements on the Arlington Building, by Louis

J. Larson : Strain-gauge measurements and analysis of the strength

and the theory of design of the so-called Schuyster system of fire- proof building construction.

Moving Laboratory to New Quarters in Industrial Building.

During the late winter and early spring, the office and laboratory

of this section have been moved to new quarters in the industrial

building. To date most of the moving has been completed. There

still remain, however, the two Emery machines in the west building

and the equipment in the Pittsburgh laboratory to be installed in the new location. These latter need special consideration. All equipment now installed in the industrial-building laboratory was moved

under the direction of the section chief. In reinstalling the machines

especial care has been taken to so place them as to afford maximum

lighting and working space. Further, each machine is being over-
192 EEPORT OF DIRECTOR OF BUREAU OF STANDARDS.

hauled and readjustments or repairs made wherever needed. This

latter was rendered necessary by the stoenuous use with minimum re- pairs of the entire equipment during the period of war. Summary of Tests Made by Engineering Materials Section.

The following statement shows various materials tested by this

section during the fiscal year ending June 30, 1919, together with

the number of specimens of each type

Tests of metals. Iron and steel

^ , , , Specimens. Carbon steel ; 263 Cast iron ~ 9 Malleable iron 6

Nickel chrome steel 2 Semisteel bars 3 Strap iron 4 Welded bars and plates 150

Total ^ 437 Aluminum and aluminum alloys

Aluminum alloys ; 252 Aluminum, chemicallsr pure 42 Aluminum solder 6 Total 300

Copper, brass, and bronze

Bronze, nickel 2 Bronze, phosphorus 7 Bronze, various 358

Copi>er , 5

Total 372

Miscellaneous metals and alloys

Alloy, lead antimony 19

Alloy, resistant metal 5 Babbitt metal ^ 8 Bearing metal 19 Dental amalgam 65

Nickel , 8

Tensilite 1

Total 125

Tests of tcood. Various species:

Cypress 56 Various 50

Total 106

Tests of fiber rope, wire rope, and chain. Chain

Sash chain 1 Various 149

Total - 150
REPOKT OF DIRECTOE OF BUREAU OF STANDARDS. 193

Wire, wire rope, and cables:

Caliles, various 39

Wire, sliot-line 10

Total 49

Fiber rope (manila, sisal, etc.) : Various G6

Tests of other material.

Bakelite type insulating material 417

Celluloid 4

Cbiiia plates 42

Disks, round 4 Sapphire balls, bearings for instruments 12

Sliellac composition 12

Total 491

Calibration of machines and instruments. Berry stain gauge 2

Brinell Hardness specimens 95

Calibration specimens 110 Dynamometers 4

Horizontal Scott testing machine ^ 2 Larson tensiometer . 9

Lewis-Hayes extensometer 1 Olsen testing machine 1

Kiehle Bros, testing machine . 2 Standard scale .spring 1 Upton-Lewis repeated stress springs 13

Total 240

Tests of fabricated parts.

Airplanes and airplane parts:

Beams or spars 23

Cables 1 Alloy steel bolts t5 Gunners' belts 37 Parachute rings 7

Pilots' belts 10 Ribs - 2

Straps 12

Struts 37 Wings, veneered 10

Total 145

Wheels

:

Artillery : 6

Steering wheels 18

24

Guns, shells, powder containers, etc.

:

Ammunition packing cases 101 Adapters and booster casings G3

Fuses, nose 3 Gas shells 5

Grenades, hand 1 Gun mount 33 Gun shells 64

142289—19 13
194 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Guns, shells, powder containers, etc.^—Continued.

(tuh steel 27 Mechanism cases 2 Powder containers 2

Projectors, steel shell 3

Rifle barrels 10

Roller bearings 9

Shell cases 4 Shrapnel fragments 2

Swivels, Browning gun 9

Total 338

Miscellaneous

Abercrombie seal 7 Acme sealing device 7

Alloy steel bolts 14 Armor mesh 2 Armor plate 26

Ball bearings 15 Brass tubing 2

Canvas covers 8 Cinchas 3

Cleavers, butcher's 8 Condenser tubes . 4 Cord, exerciser 2

Electrodes 20 Hammers, steel handles 4 Handles, rope 8

Flexible contact for searchlights 6 Jacks 9 Lock nuts and bolts 5 Machetes 15 Pick mattocks 1_ 2

Piston rings and rods 8 Reinforcnig bars 53 Rings and staples 36

Rings, locomotive packing 20 Scythe blades 2

Seals, metal

Shield and wire cutter for tank 1 Springs 34

Steel fence posts 8

Steel tubing 3S

Pulleys 1 12

Nickel joints 4 Turbine 1 Welded specimens 242 Wire-link fabric 2

539 Grand total : , 3,382

Equipment.

A new apparatus for testing full-length airplane beams has been

designed and installed in the laboratory. This apparatus is so built

that the airplane beams may be tested under the combinations of

loadings (rib loads, pull from guy wires, and thrusts from struts)

actually acting on a beam when installed in an airplane.

A 10,000-pound repeated bending testing machine capable of taking

specimens 30 inches long and 12 inches wide has been designed and

constructed. The machine was originally developed to study the

fatigue-resisting properties of electrically welded ship plate.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 195

The great need for an accurate device for the calibration of testing

machines has led to the design of a dead-weight calibrating machine that would permit of calibrating testing machines by a standard calibration bar. The present maximum capacity of the machine

is 100,000 pounds. While the machine as constructed is not considered ideal, it will, it is believed, be more accurate than anything now

used for calibration purposes. The machine has been constructed

and is now awaiting assembly and adjustment. In conjunction with

this machine, it is proposed to use a standard calibration bar having

a lo-inch gauge length and suitably formed ends. This calibration

bar of heat-treated nickel steel will be loaded with standard deadweights and its deformation accuratel}^ measured. Observations on

the deformation of the same bar in testing machines will allow their

accuracj^ to be determined.

A new 50,000-pound capacity, high-standard. Universal testing

machine, manufactured by the Tinius Olsen Testing Machine Co. ancl capable of taking tension or compression specimens 8 feet long, has

been installed in the laboratory.

A Brinell hardness testing machine, a gift from the United States

Army, and manufactured by the Scientific Instruments Co., of Pittsburgh, has been added to the equipment.

The laboratory equipment has been further augmented by the addition of several extensometers of the Bureau's design, a new recording

scleroscope, and a Leeds & Northrup indicating pyrometer.

CEMENT, CONCRETE, STONE, GRAVEL, AND SAND.

(Invpstipation and tpsting of materials for construction purposes ; development of now

methods of trstinsr : improvement of apparatus for testing; preparation of specifications covering structural materials ; development of new uses for cement products ; distribution

of knowledge as to use of materials; design and fabrication.) The beginnirg of the year found the work of this section greatly

congested, with practically all of its facilities devcted to war

cervice. The testing and inspection of cement for the Government

departments had increased to such proportions that the extension

of facilities for this work during the latter part of the preceding

fiscal year required still further enlargement, and the normal in- vestigation work had almost wholly given place to emergency re- search and testing required by the Army, Navy, and by the Shipping

Doard. Following the signing of the armistice, cement shipments

and the corresponding amount of testing fell off markedly, while

the military research work diminished more gradualh^ In the

latter part of the year a portion of the prewar investigative work

was resumed, but a considerable amount of work initiated by war

problems was continued throughout the year and will need to be

kept up in the future.

At the close of the year the most serious problem confronting

the section was the maintenance of its organization of branch laboratories, two of these (at Denver and San Francisco) having been

transferred the year before from the Eeclamation Service. These

two laboratories should be continued for the very valuable service

they are capable of rendering in the West, not only in connection

with the inspection and testing of cement and other structural

materials but particularly to meet the needs of reclamation and

highway work.
196 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

New Branch Laboratories.

The construction of the large Army and Navy supply bases at Brooklyn in the latter half of the calendar year 1918 required

nearly 900,000 barrels of cement. This was largely drawn from

the mills in the Hudson River district, and in order to meet the

testing and inspection requirements of these arid other projects, a

fully equipped cement-testing laboratory was established at Hudson,

N. Y. This laboratory was in operation nearly four months, from

August to November, inclusive, 1918. The work in this district was

thereafter handled by resident inspectors, the tests being made at the Northampton (Pa.) laboratory in the Lehigh district. It also seemed desirable to increase the Bureau's testing and investigating facilities on the Pacific coast. After considering the needs of

the Army and Navy and the Emergency Fleet Corporation at Los

Angeles and S'an Diego, a very convenient laboratory for chemical

and physical work was installed in one of the more permanent

exposition buildings at San Diego, where tests of cement, aggregates, and sands, iron, steel, etc., have been in progress since last November. This laboratoi'y has been especially helpful in the construction of concrete ships, and to both the Army and Navy in their

construction of aviation fields on North Island. Owing to lack of

funds for its further maintenance, this branch will be discontinued

July 31, 1919.

On account of the concentration of testing work in the Lehigh

district, a well-equipped chemical laboratory was established at NorthaiDpton, Pa., to eliminate the delay arising from sending

chemical samples to Washington or Pittsburgh. Since the amount

of cement tested and inspected in the Lehigh district is always

relatively greater than in the other cement-producing districts, this

chemical laboratory should be permanently retained.

Routine Inspection and Testing of Cement.

Shipments of certified cement for Government construction work

during the fiscal year were by far the largest in the history of the

Bureau. The total shipments for the year amounted to more than

6,500,000 barrels, of which the total cost to the Government was

approximately $160,000, or slightly less than 2* cents per barrel. It may be noted that the cost of this work necessarily included the

cost of a large part of the equipment required hj the branch

laboratories, as well as the actual cost of inspection and tests. It is further interesting to note that the cost of this work alone con- siderably exceeded the entire appropriation for testing structural

materials, only a small portion of which can be allotted to the testing

of cement. While the inspection and testing of cement during the

next fiscal year for the Government departments is estimated to be

only about 35 per cent of the amount required in 1919, it is imperative that the work be provided for by direct appropriation. The

reim.bursement plan which has been followed as a war measure has

proven to be impracticable, and while it will be again necessary to

start the new year's work on this basis, it can not be so continued

indefinitely. Too much emphasis can not be placed upon the recom- mendation that the work be adequately provided for, or else abandoned entirely.
KEPOKT OF DIEECTOR OF BUREAU OF STANDARDS. ' 19-7

The following statement of the quantities of Government-purchased cement certified by the Bureau during the past three years

shows clearly how the war affected this part of the work of the

structural materials division.

Month.

Shipments of tc?ted cement

in barrels. Month.

Shipments o{ te^^ted cement

in barrels.

191C-17 1917-18 1918-19 191G-17 1917-18 1918-19

Julv 36, .'^68 14,941

58, 765

3?, 1=^0 27, 388 16,012

29, 063 43,744

81,364

102, 2?9

146, 249

32, 366 20% 959

183,406

It'^, 104 270,964

1, 121,960

1, 053, 167 1,053,998

948, 937

719,711

247, 137

186, 806

182, 265

54, 525

48, 718

64, 325

76, 646

335,999

605, 128

76°, 395

752, 161

311,210

280, 229

255, 646 October 227, 857

Total 502, 845

72, 000

3, 597, 354

331, 000 6,688,9X3 Rejected cement «. 742,000

.

a Ti e tot 1 amount of rejected cement in 1917-18 and 1918-19 was greater than indicated in the table. ThU i ; liie to t>-e f !Ct h t records were not availal le from two commcrfiil labortories acting lor and under

supervisi.n of the Bureau in the Middle We.t and soutliea; tern di- tricts. The greater part of the cement shipped during the past fiscal year was used on rush work of a military character, such as terminals,

forts, factories, shipyards, dry docks, roadways, and bridges. In addition, a considerable quantity of specially ground cernent was tested for the concrete ships built under the supervision of the Shipping

Board.

Inspection was made at mills in 25 States, as follows : Alabama,

California, Colorado, Georgia, Illinois, Indiana, Iowa, Kansas, Kentucky, Maryland, Michigan, Minnesota, Missouri, Montana, New

Jersey, New York, Ohio, Oklahoma, Pennsylvania, Tennessee, Texas,

Utah, Virginia, Washington, and West Virginia.

Development of Testing Methods.

During the latter half of the year some progress has been made in

systematizing and improving the methods of proportioning materials

employed in the laboratory for fabrication of test pieces of mortar

and concrete, which it is believed will aid in obtaining more accurate and uniform test results. A stud_y has also been made of the effect of

variations in the storage and curing of test pieces. A new method

has been devised of measuring the " consistency " or " flowability " of concrete, these terms referring to the somewhat indefinite, but very

important, property of concrete mixtures which is primarily dependent upon the amount of water used in mixing.

Methods of Proportioning.—Although in the field concrete materials are proportioned by volume, it is essential in the laboratory that

weight per cubic foot be known to insure accuracy in duplicating

tests and eliminating a variable which may obscure the real differ- ences in strength which should be obtained vvhen comparing differ- ent aggregates or in repeating tests with the same aggregate. Often

weights are reported as loose weights, determined by allowing the

material to fall into the measuring vessel without jarring or tamping.

In other cases weights may be reported as packed or tamped Aveights.

The method now employed in the laboratory is to fill the vessel one- fourth of the height and shake and bump until no reduction in volume

is apparent, repeating until the vessel is full. The top is then lev-
198 KEPOET or DIRECTOR OF BUREAU OE STANDARDS.

eled with a straightedge and the net weight determined. The weight

used in proportioning and in reporting the result of this test is 95

per cent of the packed weight so determined. Many tests have shown

this 95 per cent packed weight to be approximately the average of

the loose and packed weights. Since the weight of 9i pounds per

cubic foot assumed for cement is approximately an average weight of

cement loose and packed, the A'olume proportions used in laboratory

tests are true volume proportions.

Storage and Curing of Test Pieces.—In conne'tion with tests of

concrete aggregates, observations have been made of the effect of

storage and curing conditions on the compressive strength of concrete up to 28 clays. Test pieces molded from the same batches of

concrete, in every way comparable, were stored in water, in damp

sand, and in a damp closet. In general, it may be stated that imder

properly controlled conditions these methods are equally satisfactory.

The results obtained varied so slightly that for any one concrete the results of all test pieces could pi'operly be averaged. Temperature conditions under all three methods were practically the same, so

tliat with this sometimes variable factor eliminated it maj^ be stated

that any method of curing is efficient which permits all water to be

retained in the specimen and permits no evaporation to take place.

In a humid atmosphere, such as the damp closet, a sprinkling once

daily apparently permitted no essential loss of moisture from the mass. This condition should be especially reassuring and satisfactory to drain tile and other cement-product manufacturers, since it shows that closed rooms kept moist by occasional sprinkling during

the curing period, furnish efficient means of stoi-ing these products.

It should not be assumed from this that additional benefit will not

be derived from a well planned and operated system of steam curing.

Flowahility of Concrete.—Work which has been done in the laboratory in connection with tests of methods of proportioning concrete mixtures emphasizes most strongly the importance of being

able to measure and express the important and fundamental quality

of flowability of concrete. In actual work some minimum fiowability must be attained, and laboratory concretes should be made

with this requirement in mind, since on tlie job, if the concrete does

not have sufficient flowability, more mixing water will be added.

Such a property and condition is a necessity, but it is well known

that increase in water lowers strength. Therefore, it is essential

that aggregates tested in the laboratory should be tested in concretes having the same conditions of flow. Otherwise, misleading

and incorrect conclusions will be drawn as to their relative values

for concrete making.

In the last annual report a method for determining the consistency

or flowability of concrete in the field was described. The apparatus

consisted of a piece of cj'lindrical tubing 6 inches in diameter by 12

inches high, which was filled with freshly-mixed concrete and then

withdrawn vertically from the mass. The amount of settling of the

unsupported concrete depended upon the amount of water used, and

was, therefore, a measure of consistency. This test, commonly known

as the " slump " test, was fairly well adapted to the rich mixture employed in ship and highway construction, but was found to be un-
KEPOET OF DIREOTOR OF BUREAU OF STANDARDS. 199

suited to the leaner and widely varying types of concrete which are encountered in the testing laboratory.

The flowability is now measured by molding a mass of concrete on

a metal-covered table whose top can be raised a fixed height by means

of a cam and dropped. The resulting bump will cause the concrete

to spread in circular form, concentric with its original outline, the

increase in diameter after a given number of repetitions of the bump

being, a measure of its flowability. Tests to determine the best form

of test piece, as well as the height and number of drops, are still under way, but a number of interesting facts are already apparent.

It is found that whatever the proportion of cement to aggregate,

whether a 1—1—2 mix or a 1—3—6 mix, increase in flowability is proportional to increase in percentage of mixing water. Definite figures

for flow can be obtained for concretes too dry for any ordinary practical purpose and also for con'cretes so wet that they would be ruled

off of any properly inspected work. This variation in flow with in- crease in percentage of mixing water is essentially a straight-line re- lation within the limit of practical working mixes.

Some work has also been done with an apparatus of this type in

determining the consistency of cement pastes, which is a fundamental

step in the ordinary testing of Portland cement. While a comprehensive program of experiments has not yet been carried out, it may

be stated that the method promises to be of higher merit than either

the Vicat or ball methods now prescribed in the specifications.

Design of Concrete Mixtures.

During the past year two new theories of proportioning concrete aggregates have been advanced. One of these theories is based on the

assumption that the ratio of the volume of mixing water to the vol- ume of cement in a concrete mixture determines the strength; that

the grading of the aggregate is important only in so far as it affects the amount of mixing water; and that aggregates having the same

"fineness modulus" (which may be regarded as a measure of the

average or effective fineness), even though differing widely in gradation of sizes of particles, will produce concretes requiring the same amount of mixing water, and consequently having the same consistency and the same strength. The second theory is based on the

assumption that if the amounts of both cement and water in concrete mixtures are properly proportioned to the total surface areas of the

aggregates, concretes of the same consistency and strength will be

obtained.

A considerable amount of work has been done by the Bureau in

checking the validity of these theories, particularly in so far as they

relate to the predetermination of the strength of concrete. In the

studies which have been made thus far it has been established (1)

that slight variations in the amount of mixing water have a rela- tively large effect on the flowability and strength of concrete; (2)

that the amount of water required in a concrete mixture must from

practical considerations be based on a definite degree of flowability;

(3) that the amount of water required in a concrete mixture can not

be determined by the formulas accompanying the theories referred to, nor at the present time by any known method other than by trial with a suitable apparatus for measuring the flowability of a concrete mixture. A great deal of effort has therefore been devoted to
200 KEPOET OF DIEECTOR OF BUEEAU OF STANDARDS.

the development of an apparatus of this kind, which has been described in some detail in a preceding paragraph. By means of this

apparatus it has been demonstrated that the water required to gauge

a concrete to a definite degree of flowability unquestionably depends

upon the surface area of the aggregate, regardless of its fineness

modulus; to precisely what extent this and other factors enter has

not yet been determined.

A discussion of the results of this investigation has been published

in the technical press and reported to the American Society for

Testing Materials.

Fineness Investigation.

Under this heading may be included the determination of the

properties of finely ground cements, the determination of the gradation of finely divided materials by means of the air analyzer, the

standardization of testing sieves, and the preparation of standard

cement samples.

Higher Strength from Finely Ground Cements.—On behalf of

the cement committee of the American Society for Testing Materials, a considerable amount of time has been given to the tabulation of

existing data on the increased strength obtained in concrete from

the use of more finely ground cements. An attempt also has been

made to obtain data on the costs of finer grinding, with a view to determining, if possible, whether a further increase in the fineness

requirement of the standard specifications is warranted. So far as increased strength is concerned, the fairly definite conclusion has

been reached that 1 per cent increase in fineness yields very approximately the same increase in strength as an addition of 1 per cent in

the quantity of normally ground cement. The cost data are inconclusive, not only because the estimates obtained differed widely, but

mainly because so many factors have to be considered in determining

the value of the estimates. It may be stated, however, that the

majority of the figures submitted were based on loss of production

occasioned by finer grinding, assuming the mills to be operating at

full normal capacity. Taking the figures at their face value, the

average increase in cost to the consumer appears to be nearly the same, whether he pays the higher price for finer cement or the

increased cost of a larger quantitv of normally ground cement.

An opportunity was obtained during the year to make tests of an

unusually fine cement put upon the market by a progressive manufacturer. The increase in strength obtained in comparison with the

normally ground cement was marked, and it was readily demonstrated in this particular case that the intelligent user could save money and get a better product by using the finer cement. The

investigative value of these tests, -however, lay chiefly in the fact

that general results differing from those of similar tests in the past were obtained; for example, a very great gain in strength of the

richer mixtures, but a less marked increase in the leaner mixtures.

It is not known whether this reversal is a peculiarity of the material

or whether in the decision to base all concrete tests upon accurately

controlled field consistencies the results obtained Avere characteristic

of the wetter mixtures. The entire series with this and other

cements of high fineness will be repeated.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 201

Air analyzer.—Throughout the period of the war pressure of

other work prevented further development or improvement of the

air analyzer. This apparatus is used for the mechanical anal.ysis or size gradation of finely divided materials. During the past

year it has been used in the mechanical analyses of various materials under investigation by the Bureau, particularly normal ce- ments, blended and reground cements, and cements ground by a new

type of mill. It is believed that the air analyzer may be adopted

for mechanical analyses of other materials than cement, as clays,

mineral powders, abrasives, pigments, explosives, etc. It is hoped

that original research for the wider use and development of the air

analyzer may be resumed at an early date. Standard Cement Sieves —T>\x\:'mg the year 56 200-mesh sieves were standardized. In the annual report for 1918 it was indicated

that it had become difficult to obtain 200-meslT, sieves that would

meet the Bureau of Standards' specifications. During the present

5'ear there has been a decided improvement in the quality of sieves

submitted to the Bureau for standardization. When the war came

on the American manufacturers were cut off from the their European sources of supplies of 200-mesh cloth and manufacture of the

latter was taken up in America. The American cloth was made of

somewhat different material from that obtained in Europe and pre- sented new problems and difficulties in weaving. Apparently these

difficulties are being or have been overcome, and it is now possible to obtain sieves meeting the specifications of the Bureau.

Standard Fineness Samples.—The Bureau continues to issue standard fineness samples of cement for checking up 200-mesh sieves. These are supplied in two degrees of fineness, 4G-e, 80.2 per cent passing the standard No. 200 sieve, and 47-b, 88 per cent passing the

standard No. 200 sieve. These samples are issued in sealed glass

jars, each containing about 160 grams of cement. Each sample is accompanied by full directions for its use. With these samples, 200-

mesh sieves may be compared with the fundamental standards and

correction factors obtained. During the year 131 samples were is- sued to owners of No. 200 mesh sieves, a nominal price being charged

for each sample. There has been an increased demand since the end

of the war, 110 of the above samples having been issued since January 1, 1919. About 150 of these samples were used by the Bureau in

standai'dizing sieves submitted, and checking up its own 200-mesh

sieves. Volume Changes in Mortars and Concretes.

The study of volumetric changes in mortars and concretes was

largely set aside during the war, and the present program was un- dertaken only at the beginning of the calendar year. The work has

been confined entirely to the laboratory, and special stress has been

placed on determining the volumetric changes that take place in

mortars during and following the time of setting. Up to date the

Bureau has dealt mainly with volumetric changes in l-to-3 and l-to-4 mortars and other typical stucco mixtures. Early in the work considerable study was made of the methods and apparatus for determining the volumetric changes, and it is gratifying to state that the

Bureau has been able thereby to get accurate and consistent results. Although over 50 specimens have been made up and placed under
S02 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

test, it is yet too early to draw any definite conclusions, since observations are still being continued on most of them.

It is the purpose of these investigations to determine, first, the exact amount of A^olumetric change in the various materials ; second,

the causes of these changes ; and, third, a remedy or way of offsetting

these changes without losing any of the intrinsic and necessary value

of the material. The extreme importance of these investigations has

been brought out even in our preliminary tests, as several mixes have

shown such serious cases of contraction that would seemingly prohibit their use as structural materials in their present form. As soon

as tests are comprehensive enough it is the intention to make a published report of results. Concrete Oil Storage. ' During the past year three main series of tests have been conducted

to determine the 'limitations of untreated concrete tanks for the

purpose of storing oils. Series I consists of eighteen 1:2:4 concrete tanks in which were

stored 11 mineral oils with gravities varying from 0.742 to 0.959

that is, from commercial motor gasoline to a very viecous residuum

oil—5 vegetable oils, and 2 animal oils. In each tank were placed

three 6 by 12 inch concrete cylinders, to be broken after an exposure

to the various oils. This series was started to determine the volumetric loss of oil due to absorption and penetration of the oils, but it was found that the physical properties of the oils and the temperature changes played such an important part in determining accurately the loss that these tanks were kept under test as qualitative

rather than quantitative tests. After a year's exposure to the various oils, the concrete of the tanks

and cylinders is apparently unaffected, with but two exceptions. The

surfaces of the tanks containing cocoanut and lard oils have been at- tacked and are considerably roughened. The cocoanut oil was more

active than the lard oil, but neither has affected the concrete to a greater depth than one thirty-second of an inch, and the penetration

observed when the cylinders were broken was 0.2 inch in both cases. The breaking strength of the 6 by 12 inch cylinders showed only a

slight decrease when compared with the strength of cylinders stored

in air. Series II and III consist of quantitative and qualitative tests on

l:fx'lh concrete tanks, in which the maximum-sized aggregate is one- half inch. The tanks of Series II are under no head, while those

of Series III are under a 25-foot head of oil. The oils used in these

tests were vegetable and mineral oils, the latter having gravities

varying from 0.649 to 0.970; that is, from very light gasoline to a heavy residuum oil. It was found the losses were greater the lower

the specific gravity; that where the specific graAdty was 0.875 or

higher the losses were very small. The head of oil had relatively

little effect on the rate of loss. In the tanks of Series I and II that contained boiled and raw lin- seed oils a very noticeable deposit of lime soap was observed. This

Was more marked in the case of the boiled than in that of the raw oil. Additional experiments are being started along the same line on

1 : 14 : 3 tanks preparatory to taking up the question of oil-proof

coatings to determine their relative worth for treating concrete tanks
KEPOKT OF DIRECTOR OF BUREAU OF STANDARDS. 203

for storing the lighter oils, for it is evident from the results obtained thus far from the tests that concrete tanks properly constructed are practically impervious to oils with gravities of 0.875

(30° B.) or heavier.

Waterproofing Concrete.

Although hampered by a very large amount of war work, the

Bureau endeavored to carry out a waterproofing test which had been on its program since 1916. This test called for the construction of

three concrete tanks below water level near the Potomac Eiver, the

tanks to be built by a local contractor under supervision of a representative of the Bureau. The tanks were to be constructed of 1:2: -1, 1:2^:5, and 1:3:6 concretes, respectively, each with 8-inch walls

and bottom, 6 feet square, and 10 feet deep, built in a pit, to be

kept dry during the work and for a period of two weeks thereafter.

The forms were then to be stripped, the pit allowed to fill by seepage,

and the water-tightness of the tanks to be determined. This program

was carried out in October, 1918, and all three tanks failed in the

test. This result was practically assured as soon as the forms were

removed, for the concrete had not filled properly around the reinforcement near the bottom, and pockets of considerable size were

left near the junction of Avails and bottom in all the tanks. For

this reason, the test did not serve its intended purpose, which was

to demonstrate whether any of the three mixtures would make a waterproof job without the use of integral waterproofing.

An experiment of this kind focuses attention upon the difference

between laboratory and field tests of a material such as integral

waterproofing. In the laboratory it may be assumed that workmanship is perfect, and the actual merit of the material can be determined by comparative tests of treated and untreated concrete. Quantitative experiments of this type should furnish valuable information, and such experiments will be carried along in connection Avith

the laboratory work of the concrete oil storage investigation, in

which the nature of the tests, equipment required, etc., are exactly

the same. In the field, workmanship is an uncontrolled variable,

which, if it could be measured, might be expressed as a definite

fraction or percentage of perfect workmanship. The field test is, therefore, one of waterproofing versus workmanship, of which the

results must be inconclusive. To what extent the use of waterproofing compensates for poor workmanship can be determined only to the degree that the latter is capable of measurement.

Stucco.

The work of this investigation has been confined to the application

of experimental stuccos to three penthouses on one of the new lab- oratory buildings of the Bureau. Two of these were coated with

1 :4 and 1 :6 mixtures of cement and crushed gravel screenings, re- spectively; the third was an experiment with exposed aggregate

finish in which aggregate up to one-fourth of an inch in size was

used. All of these were very successful and, in comparison with

the richer mixtures commonly specified, are a distinct advance. During the year a recommended practice for Portland-cement stucco has

been prepared by the committee on treatment of concrete surfaces

of the American Concrete Institute, in which the results of the

Bureau's investigation have been embodied.
204 KEPORT OF DIEECTOK OP BUEEAU OF STANDARDS.

Durability of Concrete in Alkali Soils and Waters.

This investigation has been suspended since 1916 owing to press

of war work. Plans have been completed to resume the field work

in the fall of 1919, which will include tests of drain tile previously

placed in the alkaline soils of the western United States as well as inspection of test blocks and various concrete structures. The advisory committee which has been assisting in foi-mulating the program of tests, as well as in the conduction of the field work, has

been increased by the appointment of members to represent the

American Concrete Pipe Association, the Portland Cement Association, and the Engineering Institute of Canada. Cement drain

tile for replacement in the drains in 1919 have been made at a fac- tory in Muscatine, Iowa, under the supervision of the American

Concrete Pipe Association.

New Material for Increasing Rate of Hardening of Cement.

Considerable work has recently been done on Cal," which is a new

material for increasing the rate of hardening of cement mixtures. It

is essentially an oxychloride of calcium in the form of a di"y, white

powder. It is not delequescent, as is calcium chloride, and can be

packed in bags and handled in much the same manner as hydrated

lime. " Cal " is added to the concrete materials at the time of mixing,

and is quickly decomposed by the water into calcium chloride and

calcium hydrate, the calcium chloride going into solution, while the

calcium hydrate largely remains in a solid, but very finely divided,

form. Thus, the beneficial effects of calcium chloride as to workability and increased rate of hardening of the concrete are obtained, to- gether with the jDrobable effects of calcium hydrate as to increased

workability and deci^eaeed permeability.

The greater part of this work up to the present time consists of

compression tests on 2-inch mortar cubes. These tests indicate that

different brands of cement respond to the action of " Cal " to a

greater extent than others. The brand least affected gave a strength

in 3} days equal to the 7-day strength of the untreated mortar, the

treated mortar containing an amount of the material equal to 5.5 per cent of the cement. The brand most affected by the same treat- ment gave a strength in less than 2 days equal to the 7-day strength

of the untreated mortar. The above results were obtained on test pieces stored in water. Test pieces stored in the laboratory air gave

much more favorable results, the treated mortar giving a strength in

about 2 days equal to that of the untreated mortar at 28 days. This

indicates that " Cal " would be very effective in concrete construction

exposed in any way to the drying-out action of the air or sun, and in

places where it is difficult or impracticable to keep the concrete continually wet during its early hardening.

The investigation is being continued Avith concrete, using various

mixes and 6 by 12 inch cylinder test pieces. Corrosion tests have also

been started. Sufficient data have not been obtained from these tests to make any conclusions possible.

Acceleration of Hardening of Concrete by Steam.

Experiments were made to determine how strong a 1 :2 :4 concrete could be produced in 48 hours, using steam applied internally and

externally to the mass of concrete. These tests were made at the
EEPOET OF DIKECTOB OF BUREAU OF STANDARDS. 205'

request of the Inventions Section Army War College. Twelve-inch

<;ubes of concrete were subjected to the following methods of curing:

Indoor air, external steam, steam flowing through embedded, per- forated pipes, steam flowing through nonperforatecl pipes. Use of

perforated pipes proved impractical, due to clogging of the pipes.

All three methods of steam curing gave practically the same strength

at the end of 48 hours. This strength was from 200 to 400 per cent of

the strength of air-cured concrete of the same age, depending upon

whether cured indoors or outdoors, and was about equal to the

strength of air-cured concrete seven days old. Automatic Freezing and Thawing Apparatus.

This apparatus, designed for the purpose of making extensive

weathering tests on building stones, concrete, bricks, etc., has been

experimented with to a considerable extent during the latter part of

the year. Forty-eight freezings and thawings can be made in one

day, but owing to difficuties experienced in keeping the specimens

damp the frost action is not as rapid as desired. Some changes are being made in the apparatus in order to overcome this difficulty.

Investigation of Building Stones. Extensive tests are being made on Indiana limestone to establish

data for a more definite grading of the material and to determine the

relative value of the different grades. Tests have been made on 72

samples of the material. Some work has been done on granite in

connection with the cooperative investigation of building stones. Tests were made on several samples of quartzite, in cooperation with

the United States Geological Survey, to determine its suitability for use in nitro-acid towers. Some time has been given to the study of

the thermal expansion of marble for diurnal temperature changes.

The results indicate that there is a slight permanent increase in di- mensions of newly quarried marble when subjected to the weather.

A report of the Bureau's work on the commercial marbles of the

United States has been issued as Technologic Paper No. 123. Service Tests on Floors and Concrete-Floor Treatments.

Several rooms in the Bureau's buildings have been surfaced with

congoleum and mastic flooring, giving a variety of service conditions on these materials. These materials are being studied under the

various conditions of use. Numerous inquiries have been received during the past year con- cerning the value of different treatments for concrete-floor surfaces

to prevent dusting. In order to secure reliable information on this

subject, an investigation has been started which consists of service

tests on a number of floor panels treated with different materials.

These panels are being carefully noted at intervals and compared with

sections which were left untreated. The treatments under test may

be classified as follows: Magnesium fluosilicates, paints and varnishes, waxes, and miscellaneous treatments, such as soap, linseed oil, sodium silicate, and alum. The majority of the treatments have been

beneficial, the fluosilicates and sodium silicate being perhaps worthy

of special mention. All paints and varnishes have been satisfactory

and require longer exposure to traffic to demonstrate their relative

durability.
208 KEPORT OF DIRECTOK OF BUREAU OF STAITDAEDS.

Reinforced-Concrete Investigations.

A large portion of the investigational work in reinforced concrete has been carried out for the Concrete-Ship Section of the Emergency

Fleet Corporation under the direction of a member of the Bureau's

scientific staS. Details of this investigational Avork are given in the

following paragraphs. A paper giving a summary of the most important of this work was presented at the annual meeting of the

American Concrete Institute, June, 1919.

Corrosion Tests of Reinforcing Steel.—The corrosion tests were made to obtain information relative to the importance of corrosion of

the reinforcement in concrete ships and to methods of preventing or mitigating corrosion of the reinforcement. About 20 proprietary

coatings, including paints and asphalts, were used as protective coatings, and salt-spray tests were made to determine their effectiveness.

Many of the coatings were found to be effective in preventing corrosion, hut to have serious effect in reducing the bond strength of steel when embedded in concrete. Bond Tests.—Pull-out tests of specimens, consisting of steel bars

coated with the protective coatings previously referred to, were made

on about 400 specimens. These tests showed that practically all coatings, even including metallic coatings such as zinc, had a cleleterious

effect on the bond strength (the resistance to slipping through the

concrete) of bars embedded in concrete.

Re]')eated Reversal of Load on Reinforced-Concrete Beams.—The

tests reported in the Annual Report for 1918 on double-reinforcedconcrete beams loaded in alternate directions have been carried further. Four beams have been tested to failure, and in all cases failure was by tension in the steel. One beam which has had 2,000,000 applications of the design load shows no indication of the approach of fail- ure. In one beam there was a large amount of slip of a reinforcing

bar before failure occurred. Within the limit of these tests there is no indication that the strength of a doubly reinforced-concrete beam

(reinforced for bending in opposite directions) is determined by the

properties of the concrete, if the ordinary requirements of design are met, unless it be that of the bond stress. The abrasion of the concrete

at the edges of cracks in reinforced-concrete ships was considered as a possible danger, and the tests were initiated to obtain information on

this subject.. There is no indication that this is a real danger. Not

all the tests originally planned have been completed. The danger of

slipping of bars either where they are lapped at the center of the

span or where at the end of the beam they do not have anchorage by

hooking of the bars is one Avhich should be investigated and on which

certain of the tests already planned should give information.

Impact Tests on Concrete Blabs and Built-uf Steel Plates.—In an

effort to secure a basis for comparison of resistance of concrete slabs

and steel slabs to impact, tests were made in which the impact wns

furnished by dropping a 1-ton ball upon the center of the slab. Eight

reinforced-concrete slabs and one steel slab designed to represent conditions for the shells of reinforced-concrete ships and of steel ships,

respectively, were tested. Six of the reinforced-concrete slabs were

feet 6 inches by 7 feet in size, and two of them were 10 by 10 feet. The

steel slab was 12 by 10 feet 2 inches in size. Leakage of Water Through Cracks in Reinforced-Concrete Shell.—

Early in the investigation of shearing strength of reinforced-concrete
EEPOKT OF DIRECTOR OF BUREAU OF STANDARDS. 207-

beams it was found that cracks were likely to form when shearing

stresses were considerably lower than those which it seemed necessary

to use in the design of concrete ships ; yet it was not known whether

these cracks were such as would permit leakage of water through

them or not. Tests were made in which hollow beams were loaded

in such a way as to cause diagonal tension cracks in the side walls at the same time that the beam was filled with water, which was maintained under pressure varying in head from 15 to 30 feet. These

tests indicated that the smallest crack which could be detected, say, 0.001 inch or less in width, would permit the passage of enough

water to cause a moist surface on the outside around the crack. As

the crack width increased the leakage increased rapidly, provided

that time was not given for the closing up of cracks by the deposit

of sediment of any kind. When the crack was 0.01 inch wide water

spurted clear of the outer surface of the beam. When the beam was

allowed to stand overnight with the pressure head and the load

maintained the leakage was decreased markedly. This was probably

due to the deposit of a substance which helped to fill up the cracks.

Further indication of this was shown by the appearance of efflo- rescence on the surface of the beam in the neighborhood of the cracks.

If the cracks had been very small at the time of their formation and

had developed very slowly, it is possible that the silting would have

kept up with the opening of the cracks and that leakage would not

have occurred. Apparently this is what has happened with some of

the concrete ships and barges which are afloat. An inspection made

on a concrete ship which had been in the water about a year showed

the presence of cracks which were large enough to cause leakage

under the conditions to which these test beams were subjected. However there was no leakage, although the cracks were below the water

line, and apjparently there had been none. There was efflorescence apparent at cracks on the inside of the hull, indicating that the

process of silting had been taking place.

Sheer and Comfression in heinforced-Concrete Beams.—These

tests were begun as a part of the study of reinforced concrete in

adapting it to use for the construction of concrete ships. One of the

first serious difficulties in the designing of concrete ships was that of

getting sufficient strength to prevent cracks forming diagonally in

the vertical sides of a ship of practicable weight. Using the methods

ordinarily employed in reinforced-concrete design, a shell thickness

of at least 15 inches would have been required instead of the 4 inches

used in the 3,500-ton cargo ship. Tests of large reinforced-concrete

beams were started to make certain that no mistake was being made

in using a 4-inch shell. These first tests were made on {a) beams 4

feet 4 inches deep and 18 feet 6 inches long; {h) one beam 10 feet deep and 22 feet long; and (c) specimen ship frames of full-sized scross section and 20-foot span. The frames were cut off at a point

corresponding to the point of inflection, or 4 feet 6 inches above the

top of the keel. The tests were made in the 10,000,000-pound testing

machine at the Pittsburgh laboratory of the Bureau of Standards.

For the beams the load was applied at the center of the span upon

the upper flange. The beams were supported at each end on a steel- plate girder. The beam, 10 feet deep, was first loaded 40 times with

640,000 pounds, which was four times as much as the maximum which

the standards of the joint committee on concrete and reinforced con-
2:08 KEPOET OF DIKECTOK OF BUKEAU OF STANDARDS.

Crete would have allowed as its working load. The widest crack at the first application of this load was 0.013 inch, and with 40 repetitions of the load, thei-e was no appreciable increase in the widths of

the cracks. The beam was then inverted and load was applied in

the opposite direction, causing failure at 1,363,000 pounds, or nine

times as much as the joint committee standards for reinforced- concrete design would have allowed as a working load.

The ship frames were tested by applying first only a vertical load

and adding later a horizontal load at the sides corresponding to the

horizontal water pressure on the sides of the ship. It was found

that the strength here was about eight times as great as the joint

committee recommendations allowed for the working load, also that

the shear due to the horizontal forces reduced the stresses set up by

the shear due to the vei'tical forces; in other words, that the horizontal water pressure would reduce the stresses caused by the verti- cal shearing forces on the frame.

These tests made it possible to design with confidence for shear in

reinforced-concrete ships, using working stresses much higher than

those which are recognized hj the final report of the joint committee.

In effect, the joint committee report limits the amount of web re- inforcement to about three-fourths of 1 per cent, while these tests show that for deep beams a much larger amount of reinforcement

would be effective. Apparently the main reason for the higher

shearing strengths found in these tests is the larger percentage of

web reinforcement Avhich may be used effectively in deep beams

where the web bars have much better chance for anchorage than in

shallow beams.

After these preliminary tests were completed a more nearly ex- haustive investigation was initiated at Lehigh University, Bethlehem, Pa., for the Concrete Ship Section of the Emergency Fleet Corporation.

In the economical use of building materials the importance of

using higher shearing stresses in reinforced-concrete beams has been

recognized by many. The results of the tests made for the Concrete. Ship Section wei'e so significant in this direction that the Bureau of

Standards continued the investigation after the program of tests as

related to concrete ships was completed. In all 172 beams have been

tested, and the results have been quite fully worked up, giving data

for a technologic paper which should be of much importance to the

reinforced-concrete industry.

The conclusion from these tests is that not only working stresses in shear may properly be increased, but that they may be increased

to such an extent that other features of the design become the controlling features. In order to make use of the high shearing stresses permitted, compressive stresses would be increased beyond all present

reasonable values. This led to the making of tests to deterriiine if an increase in compressive stresses was permissible. These tests were only four in number and not sufficient to afford a basis for a general conclusion, but, so far as they go, they indicate that higher

working stresses in compression than are now generally recogniized

could be used with safety. It is important that further tests of this

kind be made.

Beinforcement for Concrete Slabs.—There has been much uncertainty as to the relative economies of reinforcing slabs with (a)
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 209

bars in the direction of the span, (b) bars making some angle with

the span, and (c) expanded metal. Twenty-six slabs 4 inches thick were tested, in each of which one of the three methods of reinforcing

described above was used. The results as they stand indicate that

the largest amount of steel is required in the case in which the bars

dre placed diagonally with the span, and that as regards quantity of

steel required there is a slight advantage for expanded metal over the

use of bars in the direction of the span. However, certain conditions

of the tests make it important that more tests be made before this

question is considered to be settled. Length of Lap Required for Reinforcing Bars.—Tests were made

to determine how great a length of lap is necessary for cases in which

the reinforcing bars used are shorter than the span and are spliced

by lapping them in the center of the span. Four beams were made

in this series, and the indication from the test results is that for this

size of bar (one-half inch round) a lap of about 50 diameters is re- quired. The concrete used in these beams had a strength of about

5,000 pounds per square inch, and it is to be expected that with a

leaner concrete a larger lap would be necessary. Some information

from tests in which expancled-metal reinforcement was lapped in the same way is available. As to quantity of steel required for the lap,

this indicates a slight advantage in favor of expanded metal.

Value of Brackets and Haunches in Flanges.—For purposes of

architectural effect, or for increasing the strength, connections between columns and beams are frequently provided with brackets. This

development sometimes takes the form of an arch construction. However, in the design little attempt is usually made to determine how

much strength is added by the presence of the haunch, and usually

advantage is taken of only a portion of the value of the haunch or

bracket. In the design of i"einforced-concrete ships the strength

value of such brackets is of much importance. To obtain information on this subject, a series of tests was made, including as test specimens eight reinforced-concrete frames having a span of 14 feet, a height of 7 feet, and brackets ranging from no bracket to one so large as to give the appearance of an arch. These tests indicated

that the brackets had much more value in strengthening the frames

than that for which allowance is usually made in the design. The

results are of much importance, since the weight of the frames in a

concrete ship can be reduced materially by taking full account of the

strength added by the brackets in the frames. If the results are adapted to general design in reinforced concrete, they will have an

important bearing on the reinforced-concrete industries where such

stnictures are involved.

Shrinkage of Concrete in Setting as Related to Concrete-Ship

Construction.—It is recognized that shrinkage of concrete occurs during setting. In many constructions this is manifested through

cracks which appear in the concrete surface, but the laws which

govern this shrinkage have not been very thoroughly determined.

This subject becomes important in connection with the concrete ship,

since, as pointed out in a previous paragraph, the smallest cracks

will permit a slight leakage unless silting prevents it. In one of the

barges constructed by the Emergency Fleet Corporation for the In- 142289—19 14
210 KEPOET OF DIRECTOR OF BUREAU OF STANDARDS.

land Waterways Commission a series of careful measurements was made in the effort to determine why more frequent and larger cracks

occurred in this barge than occurred in the others. While the effort was not entirely successful, the measurements did show that there was an elongation and shortening of the barge which corresponded

closely to even the slightest rise and fall of temperature. With any

rise in temperature the cracks began to close, while with a decrease

- in temperature the cracks opened. The largest crack present was

less than 0.01 inch, and although tlie barge was not loaded the results of examinations of concrete ships which have been in service indicate

that a deposit of silt or efflorescence will prevent leakage through

cracks of this size. Reinforced-Concrete Freight Car.—During the year a gondola

freight car with superstructure of reinforced concrete was designed

and built by J. B. Strauss, consulting engineer, Chicago. During the

construction of this car a representative of the Bureau of Standards

advised with Mr. Strauss and made an inspection of it after its completion and inauguration into service. After the car had been in

service about three months, during a part of which time it was used

for hauling coal, an inspection of it was made at Washington by

representatives of the Bureau. This indicated that although there was some abrasion of projecting parts, this cay had stood up fairly

well under service conditions.

Reinforced-Concrete Flat-Slah Design.—Several urgent applications for investigational work on the reinforced-concrete flat slab

have been made by those commercially interested. With two ex- ceptions it has not been possible to make these investigations on ac- count of the interference with war work. Plans have been projected

by which a long series of tests of slabs conforming to various designs would be carried out. An expression of the willingness of

certain interested concerns to cooperate in this work has been secured,

but at the present time funds are lacking with which to meet the

part which it seems proper that the Bureau of Standards should

assume. One of the investigations now under way would have af- forded a good starting point for this investigation, but the lack of

funds to carry out the work together with the importance of starting

the present investigation at once rendered this impracticable.

The controversy over the jDroper moment coefficients for flat slabs

is acute throughout the country, and a thorough investigation of

their merits should be made. The expense is too great for any one commercial concern to undertake it alone, and the competition be- tween proprietary interests has been so great as to prevent cooperation among them to accomplish this purpose. The recent expiration

of the basic patents on the flat slab will tend to remove this i-estraint,

and it seems feasible to obtain cooperation of those commercially

interested in this problem to the end of making a thorough investigation.

Miscellaneous Concrete Investigations and Tests. Light-weight aggregates.—The investigation of light-weight ag- gregates for concrete ships begun during the past year was continued. Twelve burnt-clay aggregates were tested, these tests aiding in the selection of a light-weight aggregate bj' the Emergency

Fleet Corporation for use in concrete ships. The aggregate pro-
REPORT OF DIRECTOR OF BUREAU OF STAKDAKDS. 211

duced commercially was a light-weight burnt clay made by " puffing " or " bloating"" a clay or shale in a stationary brick kiln or a rotary cement kiln. The Bureau tests of the best varieties of this aggregate showed

that it would give a satisfactory strength (from 4,700 to 5,700

pounds per square inch at 28 days) when used in a IrfrlJ mix and

would give a concrete weighing from 110 to 115 pounds per cubic

foot (about three-fourths as much as ordinary concrete). Tests were also made using these light-weight aggregates in 1:1:1 and

1:1:2 mixes. During the investigation several varieties of slag were tested and generally gave satisfactory strength results, but did

not produce so light a concrete. Coke as an aggregate gave light

concrete, but was slightly inferior in strength. Seven varieties of

vesicular, basaltic, or volcanic rocks were tested for this purpose.

In general, these give satisfactory strength, but produced slightly

heavier concrete than the clay aggregates. Several other rock aggregates were tested. Permeability tests were made comparing several of the clay aggregate concretes, with sand-gravel concrete of the same mix, and,

although the tests were limited and not conclusive, they indicate

that the concrete made of clay aggregates is at least as impermeable

to water as that made with sand and gravel. Absorption tests show

that claj^-aggregate concrete is more absorptive than sand-gravel concrete. For a 1:1:2 mix, sand-gravel concrete showed 8 to 10 per

cent absorption in ternis of dry weight, while claj^-aggregate concrete gave 12 to 18 per cent. Tests showed that the modulus of

elasticity of clay-aggregate concrete is slightly slower, but nearly

the same as that of concrete made of sand and gravel.

Cement Gun.—An extensive series of tests was made on gunite

in cooperation with the United States Shipping Board to determine

the suitability of this material for use in concrete ships. The different phases of the question investigated were as follows : The

effect of shooting the material in a number of layers at different in- tervals, the effect of shooting the specimens in vertical and horizontal

positions, the strength of different gradations of the aggregate and

different proportions of cement to aggregate, the effect of different

pressures for shooting the material, the effect of shooting the material through screens composed of various sizes and spacings of reinforcing rods, and the comparison of the concrete made with the

cement gun and the same made by the usual process. Strength tests were made both perpendicular and parallel to the direction of shooting. The series consisted of 175 slabs of the material which were sawed into test specimens on the machines in the laboratories of the

Bureau.

The report on this investigation is being prepared by the Concrete

Ship Section of the United States Shipping Board, and no

analysis of the results has been attempted by this Bureau. However, an interesting feature of the tests which stands out quite clearly

may be mentioned, viz., that the gunite specimens showed a marked

increase in compressive strength over concrete slabs fabricated in

the usual manner. This increase for the different proportions and

gradations ranged from 23 to 70 per cent. One explanation -of this

probably lies in the fact that the gunite can be placed in a drier consistency than that required for pouring.
^12 EEPOKT OF DIKECTOR OF BUEEAU OF STANDARDS.

Concrete Atomizer.—A series of tests was made on concrete fabricated with the Brown atomizer. This investigation was also made

in cooperation with the United States Shipping Board to determine

the suitability of the material for use in concrete ships. The phases

of this question investigated were as follows : Effect of various proportions of cement to aggregate, effect of different consistencies, the

effect of different pressures of shooting, effect of blowing the speci- mens with cold air (i. e., at outdoor temperatures), hot air, steam,

and a mixture of steam and hot air. The specimens were made byshooting the concrete in forms which were divided into compartments

by horizontal and vertical rods. After the concrete had hardened

sufficiently the rods were drawn, which permitted the specimens to be easily broken cut from the slab. Satisfactory results were obtained

by blowing specimens with both cold air and hot air, but the ones blown with steam were not satisfactory on account of too much water

of condensation entering the concrete. This was thought to be due

to the fact that a long steam pipe was used without insulation. The

report of this investigation will be published by the United States

Shipping Board.

Field Control of Concrete Used in Concrete Barges.—A representative of the Bureau aided in the control of the concrete that was used

in the initial pourings of the New York State Canal concrete barges

that were being constructed for the Railroad Administration supervised by the Emergency Fleet Corporation. This consisted of laboratory tests of the aggregates to be used, the regulation of the mixture

and consistency on the job, and the taking of test cylinders of the concrete actually placed.

Corrosion of Reinforcement Due to Use of Calcium Chloride in

Gauging Water.—Plain and galvanized wire mesh embedded in slabs

of 1 :2 and 1 :3 river-sand mortar gauged with plain water and with

a 4 per cent solution of calcium chloride showed that at the end of

two years the corrosive effect of the salt introduced into the mortar was very marked. Plain wire mesh embedded in 1 : 3 mortar was at- tacked the most, being completely eaten through in places. The galvanized metal was attacked seriously, although not as badly as the

plain mesh. The metal embedded in 1 : 2 mortar was not so badly

attacked as that embedded in 1 : 3 mortar. In all cases of the metal,

both plain and galvanized, embedded in mortar gauged with plain

Water, the reinforcement Avas in excellent condition and was not rusted

and demonstrated the protection afforded by Portland cement. A

comparison of the condition of the reinforcement embedded for two

years and that embedded for one year showed that the rusting due

to calcium chloride was progressive and becomes worse with age. Reinforcing rods embedded in 1:2:4 and 1 : 1| : 3 concrete made with

and without calcium chloride also showed a corrosion due to the cal- cium chloride, but to a somewhat lesser extent. Paver Molds.—A paper mold for use as the form in which to cast 6 by 12 inch concrete test cylinders was developed for use in moldinsr

samples of field concrete. The distinctive improvement in the mold

is that it is slit lengthwise in order to allow nesting during shipment

and that it can be assembled at the job by lacing up with a stapling

machine. Each paper mold weighs only 7 ounces (one-fiftieth as much as a steel mold of the same size), and 25 of them nested for

shipment occupy only about as much space as a steel mold and weigh
REPORT OF DIRECTOR OP BUREAU OF STANDAKDS. 213

half as much. A two-ply cardboard cylinder, such as is usually

manufactured, slit lengthwise, and then dipped in paraffin, to make it waterproof, is used, ihis type of paper mold has been used by the

Concrete Ship Section of the Emergency Fleet CorjDoration to obtain

samples of concrete used in the concrete ships and barges built by it. Method of Mixing Concrete.—To determine the benefit to strength

due to mixing of cement and water for a long period (15 to 30

minutes), and then adding aggregate to produce a concrete in- stead of the ordinary method of mixing cement, aggregate, and

water together for one to two minutes, comparative tests of concrete by the two methods were made, using exactly the same materials and

amount of water. The compressive strengths obtained were about

the same, indicating that there is no advantage in long premixing

of cement and water from the standpoint of strength. Tests of Diatomaceous Earth as a Blend and Admixture in Portland Cement.—Tests made using diatomaceous earth or kieselguhr as

a blending material or an admixture to Portland cement show that in

general the strength of concrete and mortar made with the blended

cement is weaker than that made of pure Portland cement. Absorption of concrete and mortar made with blended cement has been

found to be greater.

2'ests of Old Storage Cement.—During the progress of the war

large stocks of cement were often shipped to various jobs at the

beginning of the work and stored until needed. In some cases this

storage period amounted to more than a year, and several such

samples were submitted for test. The results of tests indicated re- duction in strength for the storage cement, but this change was not

marked for material which had been stored on the job for less than

one year. One lot which had been in storage over two years gave the same strength in compression for 1 : 1^ : 3 concrete as was obtained

for a 1:2:4 concrete made with the same brand of new cement.

The old cement when gauged with a 5 per cent calcium-chloride

solution showed an increase of about 30 per cent at seven daj'S over

the same cement gauged with ordinary mixing water. Inspection 'of Buildings and Other Structures.—Assistance has

been given two Government departments during the past year in

connection with concrete structures under construction in cold

weather. In one case, after partially stripping the forms from tlie A frame of a concrete dam, the concrete appeared only partially

set and the quality of both cement and aggregates was qaestionecl.

Inspection showed the concrete not to have been frozen, but the

hardening to have been retarded by low temperatures, and it was

recommended that the mass be protected from possibility of freez- ing and allowed to stand. Tests showed the cement and aggregates

to be of good quality and that with the usual cold-weather precautions good quality concrete would result. In the second case a concrete I'oof was poured just previous to a drop in .temperature, with

the result that the upper surface for a depth of one-half to 1 inch

U'as frozen. Eather than tear out the injured section of roof it was recommended that a load test be applied after the usual period

of curing. The results of this test proved that the frozen slab had

the necessary structural strength, and removal was not necessary. The marble floor of the Arlington Memorial Amphitheater has

been developing rather extensive cracks, these being noticed before
214 REPORT OF DIRECTOR OE BUREAU OE STANDARDS.

the completion of the floor in the spring of 1918. Several inspections were made and laboratory tests were made on the floor materials.

The very rigid construction of the floor and the wide range of

temperature to which it is subjected appear to be the chief causes of the cracking. A report embodjdng the results of the studies was

submitted to the Arlington Memorial Amphitheater Commission.

Inspections have also been made of the ornamental concrete and

stuccowork at Meridian Hill Pai-k and East Potomac Park at the

request of the Committee on Public Buildings and Grounds. These

structures show only minor defects resulting from slight faults in

design and are excellent examples of the architectural possibilities in

surface-treated concrete. Miscellaneous Tests.—Aside from the tests reported in the pre- ceding paragraphs, numerous tests of a miscellaneous nature have

been performed for the Government departments, as follows: Tests of sands, sea shells, gravels, and stones to determine their suitability

for use as concrete aggTCgates; sieve analyses of sands, silica grits,

silica washes, and granulated cork; transverse strength and absorption tests of brick ; compressive strength of concrete cubes and cylinders; permeability tests of concrete and bituminous waterproofing

felts. Tests of Cement for Governmental Purposes.

During the first part of the past year the testing of Portland cement

for the different branches of the Government far exceeded the

amounts ever tested during a similar period. As a result, the total amount sampled, tested, and shipped for the entire year largely ex- ceeded that of any previous year. There were sampled 426,878

barrels. Of this amount 296,705 barrels were shipped, 35,000 barrels were withdrawn by the manufactures on account of unsatisfactory

tests as determined by them before the Bureau made its tests, and

75,000 barrels were rejected by the Bureau on account of failure to meet the requirements of the specifications. The withdrawals and

rejections also far exceeded those of previous years, but it was due

entirely to unsatisfactory labor conditions at the plants.. The manufacturers were constantly forced to replace skilled labor with new,

which always tends to interfere with proper production.

Soundness of Portland Cement.

In the course of the investigation of Portland cement which the

Bureau has been conducting for years it has produced in its experimental plant a number of cements which were unsound according to the " boiling test." Neat, mortar, and concrete specimens were made

of these cements, and they have been under observation for approximately five years. Depending upon whether the disintegration in

the " boiling test " was very slight or very marked, the neat and

mortar specimens showed expansion and cracking in from three

months to one year. However, this expansion was not uniform

throughout the specimen, but was always decidedly less on that sur- face exposed to the air during the first 24 hours' storage in the damp

closet, the surface frequently not cracking at all, while the opposite

side would show large cracks. This caused a bending of the speci- men. The strength of the small specimens was usually very high

at the early periods of testing.
EEPORT OP DIRECTOR OF BUREAU OF STANDARDS. 215

The differences in the concrete specimens were very noticeable.

These specimens, made for the determination of compressive strength

and stored in the damp closet, do not show any cracking or marked

loss of strength. The concrete specimens -made for the determination of the coefficient of expansion show excessive expansion and dis- integration when stored in the air of the laboratory. The latter

is not manifested by cracking, but by crumbling under slight abrasion. Specimens made at the same time, but stored in water, are apparently sound, being free of cracks and. very hard, but show very

marked expansion, amounting to one-tenth of 1 per cent or more. Notwithstanding the apparent soundness of the concrete, when stored

in the damp closet or in water the expansion, as shown only by actual

measurement, shows this cement to be of questionable value, and in a manner justifies the use of the present " boiling test." Magnesia Content of Portland Cement.

Notwithstanding the fact that all the specifications for Portland

cement in this countrj^ within the past few years have raised the

allowable magnesia content of Portland cement to 5 per cent, there seems to be a desire to raise this amount still further. This matter

is covered in Technologic Paper No. 102 of the Bureau, wherein the

change in constitution and properties of Portland cement with a change in magnesia content of from 2 to 25 per cent was studied.

Briefly, the conclusions were that there was no marked change until

the amount exceeded approximately 7 per cent. At the time the above-mentioned paper was issued, the concrete made from the cements in question had been under observation tor about two and a half years. The majority of the specimens are now

five years old. It is not the intention to break these and secure

quantitative data before there are evidences of disintegration shown

by the very high magnesia cement concrete. At the end of five years, however, all are apparently in excellent condition, without any signs

of disintegration. Furthermore, it should be borne in mind that the

chief fault of the high magnesia cements (MgO exceeding 7 per cent) was largely that of very low strength at early periods. Disinte<iration was not a noticeable feature of the concretes at any period,

though mortar-and-neat test pieces made from cements containing

magnesia in excess of 10 per cent disintegrated in from one to three

years. Magnesium Oxychloride (Sorel) Cements.

The development of tests for use in specifications covering the

purchase of magnesia for use in magnesium-oxychloride cements has

not progressed very satisfactorily. The principal difficulty is the

different action of the cement in mixtures used in flooring or stucco from that when used with a standard reproducible aggregate or standard Ottawa sand. In practice one of the aggregates is a fibrous

material, as asbestos or sawdust. On account of the manner in whicl'a these latter occur, it is practically impossible to secure similar materials (as to fineness, length of fiber, thickness of fiber, etc.) at different times. Therefore, it would seem to be very unsatisfactory to

use these in a standard test. These cements, however, do require a

fibrous aggregate to reduce the marked volume changes which occur

in their setting and hardening. Consequently, standard sand does
216 KEPOET OF DIEECTOE OF BUEEAU OF STANDAEDS.

not seem to furnish an aggregate which gives results that can be

correlated with those obtained from a fibrous aggregate or in general

practice. Further work is being carried on along this line, however.

At the present time the Bureau is receiving samples from shipments received by a number of composition-flooring manufacturers.

Test pieces are being made with these of both a flooring and standard

sand mix to determine both the tensile and compressive strengths at

different periods and the coefficient of expansion. At the same time

the manufacturer is making particular note of the results he obtains

in practice with these same shipments.

Concrete Columns with Cast-iron Cores.

The results of the investigation of the strengths of these columns

are incorporated in Technologic Paper No. 122, now in press. Eighteen columns for tests were fabricated by L. J. Mensch, consulting

engineer, under the Emperger system of reinforcing, in which cast- iron cores are used as the reinforcing material. The columns ranged

in length from 6 to 14 feet and were 13 inches in diameter. The

cast-iron cores were 6-inch hollow cylinders, three-fourths of an inch

thick, and were placed concentric with the axes of columns. The

total loads borne by these columns varied from a minimum of 858,000

pounds to a maximum of 1,041,000 pounds, or 6,700 and 8,160 pounds

per square inch, respectively, on the basis of equivalent columns of

solid concrete; that is, were about twice the usual strengths for such

columns as ordinarily reinforced.

The cost of fabrication of this class of columns is considerably less than ordinary concrete construction to carry the same loads and

approximately half that of a steel column of the same strength. The

rather remarkable showing as regards strength and ease of fabrication suggests that this type of construction be studied by practical

structural engineers with a view to a possible wider introduction in

building practice.

LIME, GYPSUM, ETC.

(The Tvork of the section was somewhat Interrupted by moving the laboratory from

Pittsltursh to Washington. The delay incun-ed was magnified because it was acrompanied by an almost complete change of personnel. The section is now established in its new quarters in Washington and is better equipped than it has ever been.)

Cooperation with Lime Manufacturers.

All of the manufacturing interests with which this section deals

have accorded official recognition of the work. The Liime Association, the Gypsum Industries Association, and the Sand-Lime Brick

Association have all appointed, within the past year, special committees on cooperation with the Bureau of Standards.

At its last annual meeting the Sand-Lime Brick Association passed

a commendatory resolution, which has been engrossed and presented

to the Bureau.

The section has continued its active cooperation with the American

Society for Testing Materials, and during the past year its members

have accepted the chairmanships of the subcommittees on specifications for structural lime, on methods for measuring plasticity, and on

methods of test for gypsum products.

On January 6, 1919, at the instigation of this section, there was

formed an interdepartmental conference on chemical lime. This
KEPOKT OF DIKECTOR OF BUREAU OF STANDARDS. 217-

conference is composed of 15 members, 4 of whom represent the

Bureau of Standards.

Compressive Strength of Cement-Lime Mortars.

The extended use of mixtures of lime and cement as mortar for

laying brick has brought about a demand for information as to the

way in which the properties of such mortars vary with their composition. It was found that the strength of such mortars is proportional

to the quantity of cement contained in them and to the density of

the mortar. This latter factor is affected by the quantity of lime

added. The detailed results were published in the Journal of the

American Ceramic Society for January, 1919.

Effect of Addition of Hydrated Lime Upon Properties of Concrete.

This work, which was started in 1915, was continued during the

past year by conducting experiments under field conditions at Cedar

Hollow, Pa. Concrete with and without lime was mixed in the ordinary type of concrete mixer and allowed to flow down a chute 100

feet long. The eifect of the lime upon the time required to flow down

the chute and upon the other properties of the concrete was determined. This work is conducted under the guidance of a special

advisor}^ committee appointed by the Bureau for the purpose. The

results of the Cedar Hollow experiments were presented to this committee on June 24, 1919. The committee decided that the information

at hand is not sufficiently complete to warrant the publishing of anything at present. A program for the present year's work was mapped

out at that meeting.

Carson Plumb Bob Test. A method of test, wherein a plumb bob was used to determine the

properties of lime plaster, was devised by William E. Carson. At the

request of the subcommittee on structural lime of the American

Society for Testing Materials, the Bureau conducted an investigation

to determine the practicability of this test. A favorable report was

presented to the committee, but no action has as yet been taken in the

matter. Possible Causes of Unsoundness of Lime Plasters,

The "popping" of lime plaster is very unusual, but when it does

occur, it is sufficiently serious to warrant an investigation as to its cause. Apparently little particles of the plaster expand enough to push themselves clear out of the wall, leaving " pin holes " in the

plaster. This occurs from six months to two years after the wall

has been plastered. Our investigation includes making specimens of

plaster to which has been added known quantities of suspected ingredients, storing them in the air, and watching them for signs of popping. While some of the samples have failed already, the specimens

are not yet old enough to be sure that those which are now sound will

remain so. Measurement of Plasticity.

Plasticity—ease of spreading—is the property Avhich virtually controls the selling price of hydrated lime; yet there is no generally ac- cepted method for measuring this property. For many years the

Bureau has been designing instruments to measure plasticity, experi-
218 EEPOKT OF DIRECTOK OF BUREAU OF STANDARDS.

meriting with them, noting their defects, and redesigning them. This

year one instrument was designed in February and put into operation

in May. To date, it has not given entire satisfaction. Another in- strument, of much more elaborate and complicated type, which was

designed in 1917, has just been completed. The principle upon which

these instruments operate has gradually been evolved until reasonable assurance is felt that it is correct. The changes made are rather in details of design and operation.

The method of measuring plasticity developed for lime should be

equally applicable to gypsum and all wall plasters.

Standard Sand.

For almost every purpose lime is mixed with sand before it is used. Obviously laboratory tests should, therefore, be made not on

the lime itself, but on sanded mortars made from the lime. For

this purpose, it 13 necessary to establish arbitrarily a standard sand

i^i order that every laboratoiy in the country using the same sand

may obtain comparable results. In cooperation with the American

Society for Testing Materials, the Bureau has undertaken to write

the specifications for this sand. The task is to find a sand which is satisfactory for the purpose and which cafl be obtained uniform in

quality. The work has not yet been completed.

For the reasons given above a standard sand is also, essential for

tests of gypsum. Probably the same sand can be used with both

materials.

Reinforced Gypsum.

Shortly before the entrance of the United States into the war the

application of reinforced gypsum to roof construction was developed

by one of the largest manufacturers of gypsum in the United States. A considerable amount of scientific work was done which afforded

a sound basis for the design. With these data as a basis, a member

of the Bureau of Standards' staff has participated actively in the

formulation of standards for design of reinforced gypsum. Tliese

standards have been accepted as a tentative report to the American

Society for Testing Materials and are being printed in the proceedings for 1919. During the war many thousand square feet of

reinforced gyp=;um roof designed by these standards were used in

Government buildings.

Factors Influencing Time of Set of Gypsum.

The standard method for measuring the time of set of calcined

gypsum has not yet ccme into general use; it is still subje't to modifications. This study was undertaken to determine the effect of cer- tain changes in the method of manipulation. It was found that the

addition of excess water to the gypsum makes it set more slowly;

that if the gypsum and water are mixed vigorously the set will be

hastened; that the temperature of the water has nothing to do with

the time of set. The detailed results of this work were published in

the Journal of the American Ceramic Society for August, 1918. Increasing the Strength of Gypsum and Making it Waterproof.

Gypsum is now used for the manufacture of hollow tile and of

reinforced roofs. Its inability to withstand the action of the weather

limits its field of application. After a number of experiments a
REPORT OP DIRECTOR OF BUREAU OF STANDARDS. 219

tnethod of manufacture was evolved whereby gypsum tile may be

produced having, when compared with ordinary tile, three times the

strength and three times the ability to resist erosion by water. These

results, but no details of the method, have been presented to the

Gypsum Industries Association with the hope that they will take

sufficient interest in the subject to put it into use. Measurement of Properties of Commercial Gypsums.

The tentative standard methods of test for calcined gypsum as adopted by the American Society for Testing Materials in 1919 have

not been used sufficiently to determine the numerical results which

they will give. For example, it is not known what the tensile strength

of a good gypsum should be, because so few samples have ever been

tested by the standard method. For this reason the Bureau has

imdertaken to test about 100 samples of commercial products and

to compile the results in such a way that the proper numerical values can be inserted in the specifications for these products. The tests include chemical analysis, water-carrying capacity, time of set, fineness, tensile strength, compressive strength, and yield. This

work is about 20 per cent completed.

Effect of Gradation of Sand on Properties of Sand-Lime Brick.

The properties of a sand-lime brick depend very largely upon the

quality of the sand of which it js made. Whether this sand is fine, course, or graded is very important. The sand used in these experiments was sifted into three sizes—fine, coarse, and medium. These

were then mixed in predetermined proportions, and bricks were made

of them. It was found that a mixture of 40 per cent fine sand and

with 60 per cent coarse and no medium gave the strongest bricks.

The detailed results were published in the proceedings of the SandLime Brick Association for 1919.

Factors Influencing the Bond Between Mortar and Sand-Lime Brick.

If a chain is no stronger than its weakest link, then a pier built

of good bricks and goocl mortar may not give satisfaction because

of poor bond between the mortar and the brick. Tests of brick

piers published in Bureau of Standards Technologic Paper No. Ill

show that the strength of the pier will seldom exceed 30 per cent of

the strength of the brick, even when the best mortar is U3ed. Our

experiments have shown that the bond between mortar and sand-lime

brick is affected by two factors. One of these is the laitance. When

the green brick is formed in the press, the water in the raw mix

comes to the surface, carrying with it soluble salts, which are deposited as a scum. This scum, or laitance, gets between the mortar

and the brick, and interferes with the adhesion. The other factor

is the size, number, and shape of the pores on the surface of the

brick. Sometimes the sides of these pores are bent over to form

a key to which the mortar adheres strongly. Both of these factors' are subject to control by varying the consistency of the raw mix and

the molding joressure. An article on this subject is now in course

of preparation

Effect of Duration of Hardening on Properties of Sand-Lime Brick.

The laboratory experiments on this subject, the results of which

were published in the Proceedings of the Sand-Lime Brick Asso:iation for 1918, showed that nothing is to be gained by cui-ing the
220 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

brick for more than four hours. This curing is done by exposing the

brick to high-pressure steam for from 7 to 12 houi-s. Such a marked

reduction in the time would, therefore, result in an enormous saving

of fuel, to say nothing of the additional output possible with the same equipment and overhead. The manufacturers took up the idea

with avidity and volunteered to cure brick for different periods of

time and send them to the Bureau to be tested. This was to make

sure that the results obtained in the laboratoi-y could be duplicated on a large scale. Owing to the unusual busin ss conditions some of

the manufacturers have not yet been able to make the samples for the

Bureau. The work is at present about 40 per cent completed.

Routine and Miscellaneous Work.

A lime manufacturer was receiving complaints that his hydrate was not plastic. A week spent at his plant studying the conditions

showed that the trouble was due to overburning the lime; and rec- ommendations were made accordingly. Samples of this hydrate re- ceived at frequent intervals since then indicate that the trouble has

been overcome. At the request of the Industrial . Cooperation Service, the manufacture of sorel cement was investigated. This cement was being

used for drain boards, table tops, etc., and the sawdust added to it as a filler was proving objectionable because of discoloration. After numerous tests the Bureau learned how to make these articles, using

sand instead of sawdust, without impairing the peculiar characteristics of the sorel-cement surface.

An investigation of the waste shells from the pearl-button industry indicated that, while they could be calcined to produce a good

quality of lime, it would probably be better economy to market them

as ground limestone.

The routine testing for Government purchase has been negligible,

consisting of one sample of hydrated lime for the Supervising Architect and five samples of quicklime for the Panama Canal.

Before the armistice a great deal of time was spent in active co- operation with the Quartermaster's Department, the gas-warfare

service, the forest products laboratories, and other Government agencies in enabling them to obtain the quality of lime best suit d to their needs. Meetings of the War Industries Board were attended,

wherein were discussed proposed specifications for magnesite stucco and for gypsum plaster board.

RUBBER.

(Tnvrstifiation and testing of rubber and rubber froods to determine the physical and

chemical, properties and the development of specifications.) Rubber Analysis.

On account of certain routine work on the analysis of rubber goods

it became necessary to find methods for the determination of constitu- ents not before considered. Glue is one of these constituents. Its amount can be ascertained with sufficient accuracy by determining

nitrogen by the Kjeldahl method. A reliable qualitative test for glue was also devised.

Eubber soles for shoes contain cotton and other .organic fillers. It

is hoped that a new method for the determination of the amounts of .
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 221

,these constituents, which is still under investigation, will soon be

perfected.

Considerable time has been spent during the last six months on a new method for the determination of mineral fillers in rubber goods.

Even in its present incomplete state the method gives more accurate

results than can be obtained by the usual combustion method, because

most of the fillers used are unchanged as the rubber goes into solution.

Very interesting results were obtained by the use of mixed solvents

in extracting rubber. A paper on the subject was prepared for publication. It is gratifying that the Bureau's methods of analyzing and test- ing rubber goods are generally recognized as accurate and reliable. As an illustration of this, the specifications for solid and pneumatic

tires issued by the Motor Transport Corps require that these methods

be employed.

Balloon Fabrics.

Many samples of balloon fabrics received for permeability and

aging test were analyzed.

Rubber Tires.

In the year beginning March. 1918, over 500 samples of solid truck

tires, representing about 250,000 tires, valued at about $20,000,000, were analyzed for the War Department. Army inspectors at the

various plants performed most of the routine physical tests, but samples were sent regularly to the Bureau as a means of checking their

results. A large part of this work was done during the period

covered by this report.

The preparation of specifications for pneumatic tires and inner

tubes was, for several reasons, a very difficult task, in which this

Bureau cooperated. The specifications, which were issued in October,

1918, were based on an elaborate series of physical tests and chemical

analyses made at the Bureau. A large number of tires and tubes,

representing the products of numerous manufacturers, were used for

this work. The number of samples it was proposed to send for

analysis was so great that immediate arrangements had to be made

for a larger force of chemists and more commodious quarters. The

Bureau must thank the Municipal University of Akron, Ohio, for

the use of the space and facilities necessary. This was particularly

fortunate, because Akron is the greatest center for the manufacture of

tires. Approval of tires and inner tubes for purchase by the Motor Transport Corps was based on the results of tests and analyses made by

the Bureau of Standards in accordance with their specifications.

Owing to the armistice, the branch laboratory in Akron was never

utilized to its full capacity, and it was abandoned in June, 1919.

Assistance Rendered Manufacturer of Solid Rubber Tires.

Assistance was rendered a manufacturer of solid-rubber tires in

improving the quality of the compounds used, and in improving the

bond or adhesion between the tread stock and the hard-rubber base. Various formulas, based on a three-hour cure, were suggested by the

chemical division and made up, cured, and tested in the physical

laboratory. A solid tire which met all the requirements was de-
222 REPORT OP DIRECTOR OP BUREAU OP STANDARDS.

veloped. This involved a physical and chemical study of the nature

of the bond between hard and soft rubber. Some interesting data on

this subject were obtained.

Power Loss in Automobile Tires.

An investigation will be undertaken to determine the power loss or

energy absorbed by different types of automobile tires, and to study

the effect of " tire fillers " on the life of pneumatic tires and the power

absorbed as compared with the power absorbed when inflated with

air. Special equipment in the way of electrical absorption dynamometers is being installed for this work.

Rubber Packings.

These are needed in the recoil cylinders of field guns. Work was

started over a year ago, since which time samples submitted by manufacturers have been tested. A recent undertaking was the develop-

. ment of an oilproof packing in cooperation with a concern manufacturing air brakes. Tlae Bureau's rubber plant is being used in con- nection with the compounding and vulcanization of experimental

mixtures for trial packings.

Hospital Supplies.

Many samples of rubber sheeting, tubing, hot-water bottles, air

cushions, surgeons' gloves, etc., were tested and analyzed for the Field

Medical Supply Depot. The Bureau has been requested to prepare

standard specifications for the purchase of these materials.

Tests of Fire Hose for Government Departments.

During the past year the Bureau continued its cooperation with

Government departments in testing fire hose. All fire hose used by

the local fire department is purchased on the basis of tests conducted

at the Bureau. Tests of tliis sort were also made for the Panama

Canal and for the General Engineer Depot of the Army.

Rubber Jar Rings for Canning.

A very important item in connection with the matter of food conservation is the subject of jar rings. The Bureau was requested

by the States' Relations Service of the Department of Agriculture

to cooperate in the production of standard specifications for jar rings

in order to establish a standard of quality for use by the public and

to eliminate the many inferior brands of rings that hacl been the

cause of extravagant waste as a result of food imperfectly preserved.

The Bureau's method of procedure was to imvestigate the physical

and cliemical properties of tlie various grades of jar rings on the

market and to compare the results obtained with the known behavior

of the rings in service. It was found that of the many different

grades of commercial rings obtainable those having certain physical

properties that are easily measurable may be depended upon to give

satisfactory results. Specifications written by the Bureau included

a series of simple tests and measurements, and the specifications are now published by the Department of Agriculture and recommended

for use by the public.

Miscellaneous Rubber Goods.

Rubber hose of different kinds, such as are used for steam, water,

air, etc., together with miscellaneous rubber goods, such as beltings
KEPORT OF DIRECTOR OF BUREAU OF STANDARDS. 223

valves, and packings, commonly classed as " mechanical rubber

goods," were investigated by the Bureau at the request of the War

Department. The object was to develop standard specifications for

materials of this sort to be used as a basis of awai'd in the purchase

of supplies for military purposes.

The methods followed in investigating and correlating the physical

and chemical properties of the various kinds of rubber goods had,

for the most part, been previously developed at the Bureau in con- nection with similar work for o;:her Government departments. In

addition to chemical analyses to determine the percentage of rubber

present and its quality physical tests were made to measure the quality and strength of fabric and the strength, stretch, and elasticity of

the rubber as an indication of the correctness of vulcanization. A

study and comparison was made of various articles in each of the numerous classes of materials as a means of judging the excellence

of fabrication. When practicable, the materials were subjected to conditions approximating those of service, and in some cases accel- erated aging tests were conducted as a means of estimating the

relative life of the rubber compounds used.

As a result of the laboratory investigations referred to and numerous conferences with manufacturers and representatives of the War

Department standard specifications have been adopted for practically all miscellaneous rubber goods used for military purposes.

During: the past year a total of 994 miscellaneous samples were

tested physically and in many cases subjected to chemical analyses.

The following items are representative of the materials handled:

Rubber hose (fire, water, air, air-brake, suction, steam, etc.), 98;

rubber-covered wire, 110 ; packing (asbestos and rubber, square

spiral steam, plain sheet, sheet- wire insertion, asbestos sheeting, etc.),

102; jar rings, 82; dredging slecA^es, 55; asbestos gaskets, 34; auto- mobile, motorcycle, and bicycle pneumatic tires, 128; inner tubes, 50;

solid tires, 44 ; rubber bands, 11 ; gas-mask check valves and nose

pads, 42. The majority of these tests were made at the request of the Motor

Transport Corps, the General Engineer Depot, the Chemical Warfare

Service, the Signal Corps, Medical Supplv Depot, the Panama Canal,

and the General Supply Committee in connection with contracts and

to secure experimental data for use in the preparation of specifications. Future Work in Rubber.

An interesting program of investigations on problems relating to rubber was mapped out. It is hoped that satisfactory progress can

be made during the next year. The increased laboratary space provided for the experimental rubber plant in the new industrial building will make it possible to handle a gi^eater volume of tests and to perform investigations on a

larger and more comprehensive scale than in the past. In the new

laboratory the vulcanizer will be equipped with automatic temperature and time controllers and recording thermometers, which will

eliminate certain errors in temperature regulation due to the use of

steam-pressure reducing valves.
224 KEPOET OF DIRECTOK OF BUEEAU OF STANDARDS.

LEATHER.

(Investigation and testing of leather and leather goods to determine the physical and

chemical properties and the relative durability of different kinds of leather upon which

to base standards of quality.) After the signinjr of the armistice the requirements of the War

Department for leather ^oocls were greatly decreased, and hence the

amount of routing testing- work was considerably reduced. This fact

has allowed the personnel of the leather laboratories to devote nearly

their whole time to investigation and I'esearch during the greater part

of the fiscal year. The results of many individual investigations

have been obtained and several new problems have been started. The

general plan followed has been to correlate, in so far as possible, the

tensile strength, stretch, buckle strength, water absorption, and wear, with the chemical composition, of the particular leather involved.

Owing to the nature of the material, the methods for the analysis

of leather are almost entirely empirical. It is nearly impossible to check the accuracy of a given procedure by analyzing samples of

leather prepared so as to contain a Imown percentage of a given constituent. For this renson the methods adopted by the American

LfCather Chemists' Association are folloAved closely by this Bureau.

The work during the fiscal year may be divided into the following

parts : Sole leather, harness and strap leather, upper leather, miscellaneous, development of specifications, and routine testing. • Sole Leather.

On pages 154 and 155 of the last annual report mention is made

of six different problems relative to the wear of sole leather which

it was proposed to iuA^estigate. Progre&s has been made on all of

these. Preliminary results have been obtained in the investigation

of the comparative wear of the belting tannage with the sole tannage,

and also in the investigation to determine the effects of oils and

greases on the wearing quality of sole leather, but further tests are planned before definite conclusions are drawn. Technologic Paper

No. 138 contains the results of the first of a series of tests to determine the effects of glucose as well as Epsom salts on the wearing

qualitv of sole leather. The leathers used in this test were (1) a

lone-time tannage with a minimum addition of glucose and salf^s, (2) a leather tanned to the belting stage and then filled with the

maximum amount of extract bv drumming, (3) a leather tanned to the belting stage and then filled with a large amount of glucose, and

(4) a leather well tanned and moderatelv filled with glucose and

salts. All were oak-tanned leathers. All the bends were cut into, soles according to a definite plan, and each individual test consisted

of comparing a sole filled Avith glucose and salts with one with no

appreciable amounts of these materials added. Both soles in any

test were cut from the same relative location on the hide. Service

tests were made on soldiers at Camp Meade. Md. The laboratory

work consisted chieflv of abrasion tests on the laboratorv wearing

machine, complete chemical analyses of the new and worn soles, and

water-absorption tests. The success of f-'e work was made pos-'ible

throup-h the heartv cooperation of the War DeDartment. the Tenners' Council, and the American Leather Research Laboratory. The

second test of this series has been started, the leather used in this case being hemlock without the addition of glucose and salts, hem-
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 225

lock with the addition of about 10 per cent of these materials, and

a long-time, oak-tanned leather. The hemlock leather was made

from dry hides. The amount of water-soluble materials in the two

hemlock leathers differed on an average about 11 per cent on accoimt

of the diffei-ence in glucose and salts present in each of the leathers. This fact will allow information to be obtained regarding the comparative durability of low and high water-soluble leathers. A comparison of the relative durability of oak and hemlock tannages will

also be obtained from this test. A comparison of the durability of

vegetable and mineral tannages will be secured from the following

tests, which are in progress: (1) Oak as compared with chrome

tannage from different hides, (2) oak as compared with chrome

tanned from the same hide, and (3) oak as compared with alumtanned leather from different hides. Actual service tests have also

been started to determine the effect of light and heavy rolling on the

flurability of leather from the same hides.

Several series of tests on the wearing machine to show the relative

durability of sole leatlier from different parts of the hide have been

completed, and, together with a description of the machine and the

methods of testing, will be published as a technologic paper of the

Bureau.

Harness and Strap Leather,

Investigations of harness and strap leathers were started in order

to learn the effects of different amounts and kinds of stuffing, and of

acidity upon the strength of the leather, and upon the rate of deterioration during storage. Owing to the long life of these leathers, service

tests seemed impracticable.

An attempt was made to correlate the physical properties of different harness leathers with the stuffing content of the leathers. Three distinct tests wei'e made with three different hides. One hide was tanned as regular russet harness leather, and had one side stuffed

with an average of 23 per cent grease and the other with an average

of about 11 per cent. Another hide had one side given a light tannage

and the other side a heavy tannage, and then both were finished as regular russet harness leather. Still another hide was tanned as regadar ru>set harness leather, and had one side stuffed with a mixture of 50 per cent cod oil and 50 per cent tallow, and the other side

stuffed with a mixture of 50 per cent mineral oil and 50 per cent tallow.

These tests were conducted to show the effects of different amounts

of stuffing contents, of the variation in stuffing content over the

hide, of different degrees of tannage, and of animal and mineral oils on such physical properties as the tensile strength, buckle strength,

and stretch. The results of these tests will be published within a

short time.

Upper Leather.

Water Resistance.—Several tests were made to determine the comparative resistance to water of chrome-retanned and bark-tanned

upper leather used in making Army shoes. Service tests showed

that the chrome-retanned leather resisted water better than barktanned with the particular leathers tested. Laboratory tests showed

142289—19 15
226 EEPOKT OF DIEECTOK OF BUREAU OF STANDARDS.

that if properly stuffed chrome-retanned and bark-tanned upper

leathers are equally resistant to water. In both cases the resistance

seemed to depend entirely upon the amount of stuffing content up

to the point where the pores of the leather were completely filled. Resistance to Fermenting Animal Mixtures.—The relative resist- ance of chrome-tanned and bark-tanned upper leathers to fermenting

mixtures of animal products was also investigated to determine the

relative fitness of the two leathers for use in trench shoes. The data

indicated that the chrome-retanned leather was much more resistant

than the bark-tanned.

Miscellaneous.

Leather Packings.—A heat-resisting leather is needed for j)acking

in the recoil cylinders of large guns. A number of samples furnished

by the Ordnance Department and others, tanned at the Bureau, were

tested by heating in mineral oil at' temperatures up to 225° C. for

varying lengths of time. The effects of using different stuffing mixtures were also determined.

WateriJroofing Leather.—The efficiency of different experimental

and commercial preparations for waterproofing leather was investigated.

Artificial Leather.—Increased use of so-called artificial leathers

and the absence of satisfactory tests caused an investigation to be

started and to develop standard methods of testing to determine

the quality and durabilitj' of these materials.

Development of Specifications.

During the fiscal year representatives of the Bureau have assisted

the War Department, Panama Canal, and the General Svipply Committee in developing specifications for leather. The work consisted

of acting in an advisory capacity, as well as making extensive laboratory determinations for the establishing of limits for certain constit- uents and physical properties of the various leathers. Much progress is expected during the coming year in developing standard specifications for leather. Routine Testing.

As usual, a part of the time during the year was devoted to routine

testing work for the various Government clepartments in making such

tests as tensile strength, buckle strength, and chemical analyses. The

materials tested included harness leather, strap leather, upper leather,

sole leather, belting leather, lace leather, horsehide for baseball covers, packing leather, and waterproofing compounds.

Experinnental Tannery.

Arrangements have been proposed and partially perfected for installi]ig a small experimental tannery at the Bureau to be operated in

cooperation with the Tanners' Council. Preliminary plans for a complete installation have been draAvn up, and in the event of a success- ful termination of the plans as contemplated, the Bureau will be in a position to render valuable assistance to the leather industry in

carr3dng out exhaustive investigations for the solution of important

problems relating to the tannina: and leather manufacturing industries, especially the determination of the properties upon which the

quality of leather depends.
KEPOET OF DIRECTOR OF BUREAU OF STANDARDS. 227

Laboratory Facilities. The Bureau's new industrial building, which has just been completed, provides ample laboratory space for extensive research and

testing in accordance with the program that has been planned, and

will permit of more efficient cooperation with the various Government departments to meet their increasing demands for such work.

Additional laboratory equipment is being installed, consisting of

testing machines, machines for cutting shoe soles and skiving leather^

and a complete outfit for shoe-repair work.

TEXTILES.

(Investigation and testing of textiles to determine their physical and chemical properties. Development of new materials. Pieparation of specifications.) Although considerable work has been done for the military organizations, such as the War ancL Xavy Departments, since the sig-ning of

the armistice, both directly and in a cooperative capacity, there has,

of course, been a gradual decrease in the rendering of such services,

while, on the other hand, the industries of the country have called

upon the Bureau for tests, information, and cooperation even to a

gi-eater extent than in previous times.

Identification of Fibers.

The kind of service which a fabric, jam. or material will render can alwa^'s be estimated, provided an accurate knowledge of the sub- stance is at hand. The scientific examination of such materials di- vides itself into three classes—physical, chemical, and microscopic—

with accuracy as a chief consideration in respect to the last named.

When the first two of these methods of examination do not give the

results expected, the microscopic, in general, proves satisfactory.

German-Uniform Fabrics.

One of the chief uses of the microscopic method of identification was in the analysis of the fiber content of German war textiles. Airplane fabrics and uniform fabrics were examined carefully to discover

substitute materials. A large shipment of uniform fabrics taken from

German officers and soldiers was received from the Purchase, Storage,

and Traffic Division of the War Department, to be examined carefully, tested, and studied for any useful information which might be

derived thereby. From the specimens submitted it was found that

the materials or fabrics used in the uniforms were much lighter in

weight than those used in making woolen uniforms for American

soldiers. It is thought that by a change in constriictoii more service

could have been obtained from the German fabrics.

Ramie Felts. Examination by the microscope and photomicrographic prints of

samples of a so-called ramie felt showed that 25 per cent of the fiber content was v\-ool taken from the back of a sheep. Further examination showed that the ramie fiber had been treated to increase its felt- ing qualities, giving it a very fine wavy outline, and putting it in the

class of fibers known as vegetable wools. Only a slight trace of

cotton fiber was found.
228 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Airplane and Balloon Fabrics.

Prints obtained from photomicrographic plates of airplane fabrics

showed the penetration of dopes and pigments into the interstices of

the cloth, the amount of dope and pigmented protective covering vised,

and the kind of bond which existed between them. The study was

carried out not onl}^ on American fabrics but also on fabrics taken

from wrecked or captured German airplanes.

Balloon fabrics, as well as the bonds and fastening of rubber seams

of various constructions, were studied by this means with the same

object as the study of airplane fabrics.

Sealskins.

In the process of determining the effect of two dyers' processes of

dyeing on samples of sealskins taken from the same killing the photomicrographic examination was most helioful. Two skins, considered

to be fairly representative specimens of the product of dyeing this

type of fur, were submitted. At the request of the American manufacturer tests were made to compare his method of dyeing with that

of a foreign d3'^er, the purpose being to discover the difference between

the two methods. The results shoAved that the American method was

superior. Both skins were dyed with the same dyestuff, but it was

very clearly shown that, although the chemical study indicated only a wide variation in the amount of metal used as mordants, the microscopic study presented a number of distinctions which existed between the skins.

Miscellaneous Identifications.

A large number of samples of rope, twine, cord, thread, linen, flags,

and other textiles were examined for the General Supply Committee.

Oakum Specifications.

The Bui-eau was called upon to assist in the drawing up of standard

specifications for oakum for the caulking of vessels, the need for

which had been greatly increased by the rapid growth of shipbuilding

in this country. The War Industries Board, together with the Shipping Board, found that specifications w^ere absolutely necessary to cover this class of material. A conference was arranged with the

above-mentioned boards, together with representatives of the leading

oakum manufacturers in this country.

The chief points of consideration were: (1) What constitutes a good oakum for caulking? (2) What grades of oakum should be

allowed in oakum? (3) ""Wliat should be the allowable per cent of

tar in the product? (4) What fibers should be allowed in the different grades of oakum?

As a result of this conference, a set of specifications was produced

to be used for Government purchases, and also by individual cor- porations. The Bureau was selected to act as referee in the event

of a dispute as to the grade and percentage of ingredients of oakum,

acting only in an advisory capacity.

Chemical Retting of Flax.

A great many processes were investigated as a result of the Nationwide desire for improved methods of manufacturing. The flax industry was among the more prominent of these. It is claimed that

by a chemical process the degumming and retting of flax is greatly
KEPOET OF DIRECTOR OF BUREAU OF STANDARDS. 229

sinij)lified and expedited, which would result in greatly increased

activity of this industry in this country. The new treatment is said

to dissolve the gum from the flax straw in less than one hour, leaving

fibers similar in appearance to flax obtained by processes which re- quire the submersion of the straw in water for a period of from 15 to 25 days, or in dewy meadows for a period of time from 5 to 8 weeks,

subject to atmospheric conditions. This new process is under investigation by the Bureau, but as much time is required to complete the

necessary experiments a conference was arranged at this Bureau

to obtain all possible information on the subject and to see what

could be done to aid the situation. Eepresentatives of Government

departments interested in the subject were present and had the

opportunity of witnessing a few demonstrations of the chemical

process of retting. Whether these fibers differ essentially from

water or dew retted fibers, and also the advantages derived from

chemical retting, remains to be determined.

Cotton Goods.

The chemical work done on cotton goods intended for \iniforms

consisted in determining the nature of the dye and testing the fast- ness of the color. This was carried out in accordance with methods

agreed upon by officials of the War Department interested in the

subject.

Waterproofed Canvas.

Waterproofed canvas for military use must be not only thoroughly

waterproof, but also resistant to mildew, free from objectionable

odor or poisonous material, permanently pliable in cold weather and

after prolonged exposure to sunlight. In addition to determining

the nature of the Avaterproofing material used on many samples of

tarpaulin, etc., two strenuous tests were used to imitate the effect of

beating rain and of lying on wet ground. Tests wei"e also made to learn the resistance to mildew, to cold and heat, and to sunlight.

Much of the resistance to water depends on the closeness of the weave of the cloth. When waterproofing materials were received

for test they Avere applied to suitable canvas which shoAved no " pinholes " when held up against a bright light.

These waterproofing materials and commercially waterproofed

tarpaulins differed widely among themselves as regards their behaAdor in the different tests. Analyses showed that they also differed

widely in composition.

The examination of English, French, and German fabrics obtained

through the War Department shoAved that feAv of them were as good

as the average American canvas. Woolen Goods.

Woolen cloth for unifoiuns, overcoats, shirts, and blankets Avas tested for fastness of color, nature of the dye, and for the amount

of cotton present. A large number of felt samples were analyzed

at the request of the War Department.

Commercial Dyeing Practice.

The fastness of color of cotton goods dyed in the piece depends to a considerable extent upon the skill and care of the dyer and upon

the way in which the mechanical operations are performed. In
230 KEPOKT OF DIRECTOR OF BUREAU OF STANDARDS.

cooperation with the Inspection Division, Cotton-Goods Branch, of

the Quartermaster General's Office, samples from representative mills were frequently tested. This led to the recommendation of certain

processes and the correction of the defects in the product's of contractors who were producing faulty material.

Deficiencies in fastness of color were in many cases due to faulty

mechanical processes, and not to dyes of poor quality.

American Dyes.

At the request of the Quartermaster General and the War Industries Board a collection Avas made of all the available colors for

dyeing the olive-drab shade on cotton and wool. From these strips

of cloth were dyed hj following closely on a laboratory scale the

directions of the manufacturers. These dyeings were subjected to the usual tests to show the effect of sunlight, of dye-fading electric

lamps, of washing and rubbing, of acid, etc. These test samples, more than 4,000 in number, were mounted on cards. They were much

used in conferences with representatives of the War Department.

Dye Making.

A great deal of time was devoted to the preparation of about 30

carefully purified dyes. This was done in connection with the projected development of a comprehensive method for the identification

and analysis of dyes by spectroscopic measurements. Commercial

dyes can not be used to obtain the fundamental data, because they

are rarely simple, pure substances, but generally contain colored or- ganic impurities. Different salts of metals are also frequently admixed. The optical properties of solutions of these dyes are now

being studied by the Bureau.

Mordants.

The bichromate used for mordanting wool colors was becoming

scarce toward the end of the war, and experiments were made to ascertain whether it was feasible to use other mordants. It was

found, however, that bichromate is superior to other readilj' available

materials for this purpose.

Mercerization.

The mercerized yarns produced by various mills differed greatly.

This led to a long series of experiments in order to learn the effect of certain changes in the customary process of mercerizing on the

physical propei-ties of the yarns. Flax Packing.

Many samples of braided flax packing, impregnated with tallow, were examined. The grease content and its nature and the kind of

fiber used were determined. Some of the packings contained cheaper

fibers than flax, and the lubricant contained paraffin or other cheap

materials.

Sizing.

A great deal of time was spent during the past few months in

analyzing and studying sizing compounds for use on cotton yarns.

Some of these are manifestly far superior to others. This work was

preliminary to practical studies in the Bureau's cotton mill.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 231

Camouflage.

Fabrics colored with different dyes may appear alike to the unaided eye when in the sunlight. In artificial light, or when viewed

through a colored glass or celluloid screen, they may appear as unlike

as red and green. Samples of fabric dyed in this way and appropriately colored

screens were prepared in cooperation with another section of the

Bureau. Such fabrics as these dyed green and laid on grass can

be used to convey secret signals to friendly aviators provided with

suitable color screens, while to the unaided eye they will be invisible even at short distances.

Routine Testing.

A large variety of commercial grades and kinds of fabrics, twine,

thread, yam, waste, packing, and loose fibers amounting to over

4,000 in number were tested. Of this number a fair proportion was

received from the General Supply Committee and other Government departments.

Airplane Fabrics.

Special studies were made of the standard airplane fabrics already

in use, to improve their serviceability and reliability. After a study

of the stresses of flight and stress distributions new fabrics were

designed and manufactured. As airplanes became larger and

heavier it was necessary to cover the wing with a stronger fabric,

and after the study of the stress distribution a change in the construction was recommended and applied. Since the filling carried

the larger part of the load when the fabric was applied to the wing

in the logical manner—that is, with the warp ends running from

the leading to the trailing edges of the wing—little warp was used,

thus making the fabric lighter, while capable of doing the same

work.

Tautness.

As a result of the study of the behavior of wing fabrics under

flight, a tautness meter was designed at this Bureau to investigate

uniform methods of application and treatment in securing maximum

life of a fabric after it had been placed on the wing. Under the

present methods of application of the fabric to a wing, few tests have been made to find the proper initial tension of the undoped

fabric, the elasticity of the dopes to obtain the best possible per- manency of tautness in the wing fabrics, and their method of application, and no information has been compiled which states accurately when and why a wing fabric should be redoped and replaced.

Numerous readings were taken on wing coverings of planes al- ready in service at McCook Field, Dayton, Ohio. It was plainly

shown, as a result of these tests, that the observation of the tautness can be interrupted to show the effect of humidity and temperature on the life of the fabric. A report on this subject entitled, " The

Preliminary Report on theMcGowan Tautness Meter, and a Study

of the Tautness of Airplane-Wing Fabrics and Dopes," was compiled and distributed to interested military organizations.
232 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Penetration of Dope Correlated with Tear Resistance.

Samples of linen and cotton grade A airplane fabrics covered

with different amounts of dope, applied by various methods in order

to vary the amount of penetration of dope on the fabric, were re- ceived for test at this Bureau from the commanding officer of the

Wilbur Wright Field. The test results showed many interesting

facts, and the conclusions proved of much value.

Balloon Fabrics.

After developing a standard balloon cloth, an investigation was

started in cooperation with the Bureau of Construction and Repair,

Navy Department, to increase the life and give better permeability.

A number of cloths of various thread counts and weights per square

yard have been made up accordingly and are now ready for tests. Satins.

In the determination of the wearing qualities of clothing a number

of specimens of satins were submitted and tested on an abrasion

machine recently designed and constructed at this Bureau. Although

the machine itself is in its experimental stage, the results and conclusions derived are very interesting and promising.

Banana-Plant Fiber.

At the request of the interests concerned, a series of tests were made

on the suitability of fibers taken from the stalk of a banana plant

as packing for journal boxes. A quantity of the fiber was obtained

and tested both in the laboratory and in the journal boxes of rail- road and street cars. Satisfactory service was obtained from the

fiber as packing for street cars, but it did not prove as good as the

wool waste now in use for packing boxes for railroad use. In both

experiments one side of the car was packed with banana fiber and

the opposite side with commercial wool waste. Tests of Baseballs.

At the request of the Purchase, Storage and Traffic Division of

the War Department a number of new tests were made on repre- sentative samples of baseballs, a large number of which were to be

purchased for recreational purposes overseas. A detailed and comprehensive report was compiled and submitted. The method of

manufacture, construction, composition, resilience, endurance under

wear, and other properties of each baseball were noted and recorded,

giving the purchaser some useful information from which to make

a logical award for the purchase of the same. Experimental Textile-Manufacturing Equipment.

The textile manufacturing equipment of the Bureau consists of

three units—a small felting unit, by which samples of felts are pre- pared for experimental purposes, made in such a way and of such

materials as may be desired; a complete layout of full-sized cotton machinery and apparatus to make fabrics and yarns within wide

limits; and a complete outfit of both full-sized and diminutive

woolen machines.

These machines and the necessary accessories are of the latest improved construction and are equipped with the accurate adjustments

necessary for the work intencled. The reasons for the installation

of this equipment are quite numerous. One of the fundamental
KEPORT OF DIRECTOR OF BUREAU OF STANDARDS. 233

purposes of the equipment was to aid in supplying the manufacturer

of military fabrics with exact specifications of the fabrics tl^ten being

produced. Those engaged in textile-research work were without

exact knowledge of the physical properties of such materials, owing

to their inability to obtain the necessary variety of fabrics. The

present specifications are based on tests, such as the tensile strength,

the weight per unit area, and a few other properties not used universally in all specifications, whereas the requii'ements pertain more

to such qualities as those of heat retention and resistance to wear. The making of a sample fabric in a commercial mill seriously retards

production because of the large amount of attendant waste of time

and material necessary to operate the machinery properly, with no

assurance that the sample produced will give the desired results. It is certain that it would have been very profitable to have had

such equipment at the beginning of the war before the Government

had issued contracts for textile fabrics and yarns. To-day the value

of such a laboratory is realized when it is considered that the products of the textile industry have never been scientifically investigated. Keen competition is to be looked for in the immediate future.

It would appear of essential advantage to the American manufacturer of textiles to know more exactly the factors governing the

quality of his output, in order that he may more satisfactorily compete with foreign manufacturers.

Other nations have realized the importance of this project and

have already perfected elaborate plans for limiting to their own

countries the distribution of information concerning the results of

research work.

The Bureau is not alone in this undertaking, inasmuch as the National Council of Cotton Manufacturers of this country, which represents practically all cotton mills in the United States, has pledged

its suppox't to the furtherance of the Bureau's work on the investigation of cottons and has offered every cooperation that may be desired.

Cotton.

The schedule or program of research work for the cotton mill is gi-owing rapidly, and it is thought that the work on this schedule

will soon be started, as the machine and equipment are in place and

in operation. The investigation will be restricted to the making of

yarns and fabric from the loom, but, as there are facilities for finish- ing the products, outside services will be requested when the present

program is completed.

Woolen and Felt. The machinery, and equipment of these laboratories are rapidly

being put in working condition, and it is expected that samples of

work can be taken off in the near future to be investigated as to their

physical and chemical properties in accordance with the i"esearch

program.

PAPER.

(Testing of paper, physical, chemical, and microscopical ; study and development of paper-testing devices ; investigation of paper-making materials ; standardization of paper ; manufacture and development of special papers ; study of the processes of paper manufacture ; collection of data in connection with the testing and manufacture of paper.) Routine Testing.

The amount of paper used by the Government departments is approximately 50,000 tons per year, and, as it is necessary for this ma-
234 REPORT OP DIRECTOR OP BUREAU OP STANDARDS.

terial to be tested to see that it conforms to the specifications under

which it was bought, standard methods of testing paper have been

developed. This class of work is called routine testing and consists

of chemical and physical tests and microanalysis. The chemical tests employed determine the amount of resin sizing that is in the paper,

ancl the amount af filler and loading that has been added to give the

paper bulk, opacity, finish, or surface. The physical tests used in- clude the determination of weight, thickness, and bursting strength,

as well as folding endurance and tensile strength for certain classes of paper. By means of selective stains and the aid of the microscope, the properties of fibrous material from which the paper was made can be estimated.

During the year 5,000 samples of paper were examined by these

tests, of which 4,213 samples were submitted by the Government departments and 789 samples by public and private interests. A total

of 19,545 tests were made on these samples, of which 5,397 were

chemical, 9,655 were physical, and 4,495 were miscroscopical.

Paper-Testing Methods.

In the investigation of the properties of paper it is constantly

necessary to study methods of testing this material, since the laboratory methods in general use are not suitable to determine certain

qualities. It has, therefore, been found desirable to study test methods, and, wherever possible, develop a method that will give a numerical value for the qualities that are being investigated.

The property of paper which makes it possible to write with ink

upon it is called " sizing." The sizing quality of paper is generally

determined by methods that do give an empirical rating, but which

are not very satisfactory for laboratory-research or mill-control

work. A method for this purpose which, in its simplest form, is a Wheatstone bridge, used somewhat in recent years, is being further

developed. By this method the penetration of water through a sheet

of paper is measured by the increasing conductivity to an alter- nating current, which passes through the paper placed in a cell with an electrolyte. The data so obtained are plotted in the form of a

curve, and from this curve the rate of penetration may be determined. It was found necessary to add a balancing cell which would

reduce the variation of the test due to changes in temperature. As

soon as the new apparatus is complete it is planned to study the curves obtained from tests on papers of varying sizing quality and,

if possible, reduce these data to a unit basis. The testing of the phj^sical properties of paper has been investigated with a view to establishing any relationship that might exist

between devices of the same general type and between devices that

give an indication of different properties. The properties of paper

studied in this investigation were bursting, tensile, and tearing

strength. A series of papers were tested for bursting strength by

three testing machines, and, although the data are not yet complete,

it is indicated that the principle from which each machine was developed is based on experimental data rather than on scientific principles. Similar work was done in connection with tensile-strength

testing apparatus, and it was found that there are no machines of

American manufacture especially adapted to testing the tensile

strength of paper. Since the quality of paper is so often judged by
REPOET OF DIRECTOR OF BUREAU OF STANDARDS. 235

tearing a sheet in both directions, it was thought that a method for

obtaining a numerical vahie for this property should be available.

Three types of testing devices for this purpose are being studied—

a

recording mechanism, an apparatus of the balance type giving maximum strengtJa,- and an adapted tensile-testing machine from which a number of readings can be taken and an average obtained. It is felt that a study of this property in connection with formation of the

sheet and the quality of the paper will be of considerable help to the

manufacturer.

Paper-Making Fibers.

Paper is, in general, a matted structure of fibrous materials, and it

is possible to make a sheet of paper out of nearly every kind of fiber. In the development of the art of paper making a great many plants,

weeds, grasses, etc., have been studied with a view to using them for

the manufacture of paper, and especially the quality of paper result- ing from their use. The available data on this subject are scattered,

but are of great value. The work of compiling information on papermaking fibers is well started, and its scope is as broad as is consistent

with the need of the industry. It includes a bibliography, authentic

samples with descriptions, and microphotographs of the structure of

these fibers. The well-equipped photomicroscopical apparatus has been of great

value in the study of fibers and has made it possible to obtain per- manent records of the shape and structure of these fibers. As illus- trations of the use to which this equipment has been put, samples of

paper from Germany have been photographed, making it possible

to duplicate them; it has been possible to obtain microphotographs

of unusual specimens loaned to the paper section; and the study of

Mexican hardwoods and other similar material has been undertaken.

Felts Used on Paper Machines.

Woolen felts are an essential part of the equipment of a paper

machine and play a very important role in the formation and quality

of the paper produced. During the war the amount of wool available was greatly reduced, and it was thought possible to substitute a small amount of cotton for a portion of the wool in the felt. Two felts were tested on the paper machine to determine the effect of the addition of 10 per cent of cotton to one of them. Each felt was

run for five days on the paper machine, under as nearly similar conditions as it was possible to maintain. Exhaustive tests were made

while paper was being run on the machine equipped with these felts, and it was found that the difference between the two felts was not

large enough to affect the quality or the production of the paper. It

is planned to investigate this problem further and determine whether

felts made a greater percentage of cotton can be used satisfactorily on a paper machine. Since the life of a felt is only from three weeks

to thi-ee months, depending on the machine, the speed, and the grade

of paper, any satisfactory felt that can be manufactured more cheaply

would lower running expenses.

Utilization of Waste Cotton Linters.

At the conclusion of the war the War Department had on htxad

approximately 700,000 bales of " munition " linters available for other

uses. " Linters " is a fibrous material which is left on the seed after
236 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

the staple cotton had been detached. It was thought that this material would be suitable for paper making. At the request of the Waste

Reclamation Service and the Industrial Cotton Seed Crushers' Association a series of runs was made on the paper machine to determine

the quality of paper obtained. It was demonstrated that the paper

made from this material was of good quality, free from dirt, and

that such linters were a valuable paper-making material. It is to be

noted, however, that the grade of linters used in these runs was " munition " linters and was unusually free from dirt and cinders. To

demonstrate the possibility of making paper from cotton linters, the

programs of the annual convention of the Interstate Cotton Seed

Crushers' Association in NeAV Orleans were printed on paper manufactured from this material on the paper machine of the paper sec- tion. Since about 700,000 bales per j'ear of linters can be available

for paper making, the value of this product as a raw material for

the manufacture of paper is great; and if care is taken to keep the

linters clean and free from dirt, a greater amount than this can be

used for this purpose.

Paper Bags for Lime and Cement.

The increasing use of paper bags as containers for lime and cement

has made it desirable to investigate the properties of paper for this

purpose. This work was discontinued during the war, but has been

resumed. Representative samples have been obtained, and laboratory tests have been made to determine the quality of paper- being

used for this purpose. A test machine is being used that gives the

stress-strain value of the paper, as well as the stretch under load.

It is planned to develop a test that will reproduce the strain on the

bag when it is dropped.

Due to the fact that no reliable information is available as to the

relative merits of bags, it is necessary to determine what laboratory

tests most nearly reproduce service conditions. This will be obtained

by correlating laboratory tests, by developing new test methods, and

by making service tests. As a result of this investigation it will be

possible to define the qualities of paper necessary for bags for this

type of work and to write suitable specifications. Manufacturers of

paper, as well as the lime and cement associations, are cooperating in

this work.

Use of Lime and Limestone in the Paper Industry.

Lime and limestone play an important part in the manufacture of

pulp and paper. The war has emphasized the value of lime as a chemical reagent, and it was felt that standard practice in the uses of chemical lime should be developed. A representative of the

paper section has taken part in conferences of members of the Government departments interested in lime.

The use of lime and limestone in the pulp and paper industry is being investigated. It is planned to develop specifications for lime

for the different industries, standard samples, and laboratory and

plant methods of analysis.

In this work, technical committees of the pulp and paper industry

will be consulted, and it is expected that the specifications and

methods proposed will be accepted and used by this industry.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 237

Unbleached Pulp for Papers.

Chlorine from which bleach and bleaching powder is made was in

great demand during the war for military purposes, and it became

necessary to restrict the use of this chemical for the bleaching of

pulp. It was, therefore, necessary to determine the effect on the

color of paper that the restriction in the use of bleach would cause. At the request of the War Industries Board, 21 runs were made on

the paper machine using different proportions of dyestuffs with vari- ous unbleached pulps. As a resvdt of the action of the War Industries Board, the amount of chlorine used in sulphite pulp was re- stricted to 40 per cent of the amount then used; in soda pulp, to 70

per cent; and in old papers, to 35 per cent. The.use of chlorine for

bleaching rags was restricted to 1 per cent. Filtering Paper for Gas Masks.

At the request of the Chemical Warfare Service, an investigation

Avas undertaken to determine whether paper could be made in the

United States similar to that being made abroad as a protection

against " sneeze-gas."' Tests were made on a commercial scale at two

mills, and it was proved that such a paper could be made on a large

scale in this country. Due to changes in the construction of the gas- mask canister, a different type of paper was desired, and 35 runs Avere made on the paper machine, producing a paper that was suitable for

the purpose. It M-as found desirable to have a convenient method of

testing this paper, and for this purpose a gas house was built. This

house was so arranged that the gas would be formed in one room,

and the paper tested in the next room by means of men wearing

masks and breathing through flanges so constructed that the paper

would act as a filtering diaphragm. In order to obtain a numerical

value for the protection afforded by these papers, an apparatus was

installed in the gas house that permitted a record being taken of the

concentration of the gas before and after passing through the paper.

Military Uses of Wall and Plaster Board.

During the war the investigation of wall and plaster board was

continued from the previous year. Three camps visited at the time

of their erection Avere, visited again to determine, if possible, the

degree of durability of various makes of Avail board. The results of

the inspection shoAV conclusiA^ely that almost any Avail board properly erected will give satisfaction in cantonment construction Avhen

the buildings are considered as temporary structures. Many of the

buildings Avere in poor condition, due almost entirely to the poor

method of erection. All Avail boards will expand and contract under

different atmospheric conditions, and this expansion and contraction is injurious if the board is nailed at the edges. Wall board

should be nailed along the center and the edges but lightly nailed,

and then well stripped with pieces of wood to cover the joint and

to allow for the expansion and construction of the board imderneath

the Avooden strips.

In order that further information might be obtained as to the

behavior of these boards under service conditions, a questionnaire

Avas sent to most of the military cantonments. For temporary struc- tures fiber wall board was preferred, merely because it was considered quicker and cheaper to erect and iDccause of its greater
238 REPORT OF DIEECTOK OE BUREAU OF STANDARDS.

salvage possibilities. Plaster board was preferred for permanent

construction—that is, over five years—because it was considered less subject to changes in temperature and because it makes a warmer

building. For hospital use plaster board was preferred, due to its greater resistivity to fire and moisture.

Miscellaneous Information Furnished Public and Private Interests. Specifications have been developed for a small paper mill for the

Siamese Government. Drawings were made of the plan for such a

mill, and information was obtained as to manufacturers and prices

for such equipment.

Plans and necessary equipment for a paper-testing laboratory were outlined for *the Australian Government, in connection with

the investigation of Australian hardwoods for the manufacture of

paper.

The development of the manufacture of blue-print paper was as- sisted by tests on 75 samples of this paper for a manufacturing

concern. These data are to be correlated with manufacturing conditions.

Considerable assistance has been given the Forest Service in the

work of revising the commodity classification of pulp and papers.

This classification is used in connection with the collection of data of

foreign and domestic commerce. Further work was done in the development of paper containers

for export shipment of saddle soap and grease for the War Department. Another use of paper containers under consideration was a carton to carry machine-gun cartridges. This last was to be a part

of a new feeding mechanism for machine guns, by the use of which

the belt would be eliminated.

Technical assistance was given the Federal Trade Commission in

reference to definitions of j)aper tei-ms which were claimed by that

commission to be cases of misbranding. The terms in question were

bond, vellum, parchment, Madras, nainsook, etc. JMipcellaneous information has been furnished Government departments in connection with specifications for paper, the testing

of paper, and the standardization of paper. Specifications have been

developed for private interests for special papers. Information is being collected continuously on paper testing, paper-making materials, and paper-manufacturing methods. In connection with the

information an exhibit is being prepared of papers and paper-making

materials. ^

8. METALLURGY.

[Thermal analysis and structure of metals, heat treatment and its effects upon the properties of metals and alloj'S, including the researches involved in determining the causes

of metal failures, cooling and heating curves ; the investigation of hardening, annealing,

tempering, cementation : the determination of critical ranges ; and the lU'eparation of pure metals and alloys.] GENERAL ACTIVITIES.

Cooperation with Societies and Boards.

The following paragraphs give the membership during the past

year of the members of the metallurgical division in the several sci- entific and technical societies of which they are members, and also

their relation to various Government boards and committees.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 239

Among the activities of importance may be mentioned particulai'ly

that the chief of the metallurgical division served as the representative of the Department of Commerce on the Requirements Division

of the War Industries Board. This gave an opportunity for the

Department to take an active interest in and be helped in many

exceedingly important matters coming before the Government.

Another member of the staff was very helpful as adviser in ceramics

to the War Industries Board and in framing specifications for

enameled ware as a member of the Army Committee on Standardization. Another rendered valuable service as a member of the

Interdepartmental Committee on Minerals and their Derivatives and

in blocking out and aiding in the manganese conservation program.

The committee on light alloys of the National Advisory Committee

for Aeronautics did most of its experimental work through the

Bureau of Standards, and the results of this have appeared in a

series of publications. The relations of the Bureau to the American

Society for Testing Materials have been very close, and several members of the metallurgical division have been very active in tlie committee and aiding in the framing of specifications and in presenting

for publication standards and properties of metals. The National

Research Council has actively cooperated with the Bureau in several problems, and the Bureau representatives are active on some

11 of its committees. The American Institute of Mining and Metallurgical Engineers is holding a symposium upon pyrometry this fall which promises to be a scientific and technical event of great importance. This has been arranged for very largely by the staff of the

metallurgical division. Among the important committees formed

by the Research Council during the war was one to make a survey

and recommend practice as to the ingot and finishing practices in

American steel mills. This work originated in the Army Ordnance

in connection with the woi'ks practice as influencing the output of

steel. At a recent meeting of this committee it was decided, however, not to promulgate descriptions of good practice, although the

committee had access to a fund of knowledge on this subject.

During the year the metallurgical staff have cooperated with the

following committees and organizations: American Ceramics Society; American Institute of Mining and Metallurgical Engineers;

American Physical Society; Am.erican Society for Testing Materials; American Welding Association; National Advisory Committee

for Aeronautics; National Research Coiincil; Technical Staff of the

Ordnance Department of the Army; War Service Association of

Manufacturers of Bearing Metals and Solders; War Industries

Board ; Engineering Standards Committee ; Interdepartmental Committee; Society of Automotive Engineers; and International Aircraft Standards Board.

Exhibits of War Activities.

An exhibit of scientific development in connection with the war

was held at the Bureau by the American Physical Society which was very largely attended, there being a program limited to war

topics. There was also a very extensive exhibit of war developments

in physics with entries from manufacturers and Government bureaus.

The various sections of the Bureau contributed much to the exhibit.
240 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Committee on Nonferrous Alloys.

The committee on nonferrous alloys has resumed its meetings, and

is advising very actively with the Bureau on its experimental program and is of very considerable assistance in aiding the Bureau in

outlining its investigations of nonferrous alloys.

Conferences.

Conferences have been held at the Bureau on copper pressure plugs

for testing ammunition, and a great many informal conferences have

been held on many subjects related to specifications and other phases

of the Bureau's experimental work; both testing and research in

metallurgy.

Publications in Metallurgy.

The publications by the staff of the metallurgical division include

the following, which have appeared during the year

Effect of Rate of Teraperatui-e Change on the Transformations in an Alloy

Steel (II. Scott) : Bureau of Standards Scientific Paper No. 335; Bulletin of the American Institute of Mining and Metallurgical Engineers, vol. 146, p. 157

1919. Protective Metallic Coatings for the Rustproofing of Iron and Steel (Rawdon,

Finn, and Grossman) : Bureau of Standards Circular No. 80; Chemical and

Metallurgical Engineering, vol. 120, pp. 458, 530, 591, 191S ; fourth meeting,

Annual Report of the National Advisory Committee for Aeronautics. Microstructure of Flaky Steel (H. S. Rawdon) : Bulletin of the American

Institute of Mining and Metallurgical Engineers, vol. 148, p. 183 ; 1919. A Critical Study of the Ledebur Method for Determining Oxygen in Iron and

Steel (Cain and Pettijohn) : Technologic Paper of the Bureau of Standards

No. 118. Study of the Goutal Method of Determining Carbon Monoxide and Dioxide

in Steels (Cain and Pettijohn) : Bureau of Standards Technologic Paper No.

126.Report o'f Ladle-Test Ingot Investigation (J. R. Cain and H. S. Rawdon) ; Appendix of Report of Committee A-1 of the American Society for Testing

Materials; 1919. Heat Treatment of Duralumin (Merica, Waltenberg, and Scott) : Bulletin of the American Institute of Mining and Metallurgical Engineers, vol. 1.50, p. 913; June, 1919. Constitution and IMetallography of Aluminum and Its Light Alloys with

Copper and Magnesium (Mercia, Waltenberg, and Freeman) : Bureau of Standards Scientific Paper No. 337 ; Bulletin of the American Institute of Mining and

Metallurgical Engineers, vol. 151, p. 1031 ; 1919. Mechanical Properties and Resistance to Corrosion of Rolled Light Alloys of Aluminum aud Magnesium with Copper, with Nickel, and with Manganese

(Mercia, AValtenberg, and Finn) : Bureau of Standards Teclinologic Paper No.

182 ; Bulletin of the American Institute of Mining and Metallurgical Engineers,

vol. 151, p. 1051 ; 1919. Comparative Tests of Palau and Rhotanium Ware as Substitutes for Platinum

Laboratory Utensils (Gurevich and Wichers) : Journal of Industrial and Engineering Cliemistry, vol. 11, p. 570; 1919. Science aud the After-War Period (Burgess) : Scientific Monthly, February,

1919; Journal of Washington Academy of Sciences, vol. 9, p. 57; 1919. Conservation of Tin in Bronzes, Bearing Metals, and Solders (Burgess and

Woodward): Bureau of Standards Technologic Paper No. 109; Transactious

of the American Institute of Mining and Metallurgical Engineers, p. 1742 ; 1918. Behavior of Wi'ought Manganese Bronze Exposed to Corrosion While Under

Tensile Stress (Merica and Woodward) : Bureau of Standards Technologic

Paper No. 135 ; Proceeding of the American Society for Testing Materials ; 1919. Aluminum and Its Light Alloys (Merica) : Bureau of Standards, Circular No. 76 ; Chemical and Metallurgical Engineering, vol. 19 ; 1918. Solders for Aluminum (Merica and Gurevich) : Bureau of Standards, Circular No. 78 ; Metal Industry, p. 500 ; 1918.
KEPORT OF DIRECTOR OF BUREAU OF STANDARDS. 241

Recent Metallurgical Work at the Bureau of Standards (Burgess) : In Blast Furnace and Steel Plant ; May, 1919. Letter Circular on Properties of Light Aluminum Alloys (Merica).

The following are in course of preparation or in press

:

The Study of the Deterioration of Nickel Spark-Plug Electrodes (Rawdon).

Notes on the :Microstructure of Iron and Mild Steel at High Temperatures

(Rawdon and Scott). Metallography Structure and the Related Properties of Metals ; A Revision

of Circular No. 42 on Metallographic Testing ( Rawdon )

.

An Electrolytic Resistance Method for Determining Carbon in Steel (Cain

and Maxwell).

Equilibrium Conditions in the System Iron Oxide ; Carbon and Hydrogen

in Relation to the Ledebur Method for Determining Oxygen in Steel (Cain

and Adler).

Oxygen Content by the Ledebur Method of Acid Bessemer Steels Deoxidized

in Various Ways (Cain and Pettijohn).

Investigations at the Bureau of Standards on Gases in Steel and on Deoxidization of Steel (Cain).

Cements for Spark-Plug Electrodes (Staley).

The Use of a Modified Rosenhain Furnace for Thermal Analysis (Scott and

Freeman )

.

Manufacture and Properties of Light-Wall Structural Tubing (French).

Circular on Alloy Steels (French).

Thei-mal Critical Ranges of Low-Nickel Steels (Scott). Simplification of Inverse Method of Thermal Analyses (Merica) ; Bulletin

of the American Institute of Mining and Metallurgical Engineers, vol. 151, p. 1021; 1919. Tin Fusible Boiler Plug Manufacture and Testing (Gurevich and Hromatko).

Embrittling of Steel by Pickling and Plating (Grossman and Langdon).

Properties of Certain Lead-Zinc Bronzes (Staley and Karr).

Five Foundry Tests of Zinc Bronzes (Karr).

Report of the Pyrometer Committee of the National Research Council

(Burgess).

Some Tests of Light Aluminum Cast Alloys (Merica and Karr).

Circular on Nickel (Merica).

Aluminum-Magnesium Mirrors (Waltenberg and Coblentz) ; for Physical

Society.

Metals for Pyrometer Standardization (Burgess and Waidner).

The Testing of Clays for Foundry Uses (Staley).

Metallurgical Tests. Many of the tests performed by the metallurgical division are of an elaborate nature, oftentimes entail a very considerable amount

of experimental investigation, and include all phases of qualities

of metals and alloys, as well as determinations of causes of metal

failures and of serviceability of metals.

Work for the Ordnance Department of the Army.

As an illustration of the type of work being done in detail for

several of the military establishments during the war, the work

performed for and in cooperation with the Ordnance Department

may be cited as an example. The several experimental researches

and investigations are described elsewhere. The very considerable

amount of testing performed may be emphasized here, however.

The Gun Section of the Ordnance Department provided considerable

equipment for carrying out routine tests of gun steel to supplement

and explain results obtained in the tension tests of samples taken

from gun forgings and to show the heat treatment suitable for controlling the microstructure of large guns in forging. Examinations

show that the heat treatment of gun forging has been, on the whole,

142289—19 ^16
242 KEPOKT OF DIRECTOR OF BUREAU OF STANDARDS.

satisfactorily carried out and that the inferior properties en- countered are generally due to the nonmetallic impurities. Similarly, a systematic series of. tests was made on 3-inch brass cartridge

cases, representing the product of several manufacturers, which

were studied by various methods. A general study of the defects in

slugs intended for the manufacture of shrapnel cases was made, as

also examinations of copper rotating bands, and a great many

samples of failed metals for ordnance purposes.

Testing.

The items formally entered as tests are summarized in the ac- companying table

Heat treat- ment and

thermal

analysis.

Metallographic (including

physical, chemical, and

corrosion tests.) Fusible Miscellan- Grand

total. Irons and

steels.

Nonferrous metalsIrons and

steels.

A lum- inum

alloys.

Brass and

I ronze.

Other

metals

plugs. eous.

For the Government: Bureau of Standards 31

8

•1 79 13 127 Council of National Defense 8 Emergency Fleet Corporation 1 1 2 Navy Department 1 2 6 9 Panama Canal 8 9 2 19 Patent Office 1 1 Steamboat-Inspection Service 498 498 War Dep ^rtment 21 2 134 i 5 176 War Industries Board 1 1 Coast and Geodetic Survey 1 1

Total G3 6 222 4 1 30

8 498 8 842 For the public 3 3 2 6 22

66 6 225 4 3 38 498 14 864

Correspondence.

The metallurgical division carries on a correspondence on a great

variet}^ of subjects concerning metals. A typical list is that for the

month of February, 1919, as follows : Treating black-iron plates and

rods; characteristics of boiler plugs; formulas and specifications for

brasses, bronzes, and Babbitt metals; zirconium steels; heat treat- ment of instrument diaphragms; report to Quartermaster Corps on

tests of china and porcelain ware; methods of porcelainizing ; comparative merits of nickel chromium and nickel steel for resistance

Avire ; porosity in metals ; cracks in enameled metals ; solder aluminum

joints ; car-Aviieel accidents ; metallography of iiluminum ; publication on aluminum alloys; properties of zinc sheet; steel castings by electric furnace; deteriorations of coatings on copper wire; tests for sharpness; railroad bearings; heat treatment of steel; effect of temperature on strength of bronzes; aluminum-casting alloys; use of ura- nium; j)roperties of zirconium; supply of invar; stainless steel; cor- rosion of aluminum by lead ; recalescence points of steel ; alloy steels

aging of brass; collapsible tubes; noncorrodible steels; pure nickel;

Kermat nickel; enameling; hardness of copper; new bronzes; metal

for valves; specifications for nails; annealing of phosphor-bronze

wire; identification tags; Meinheim-chamber furnace system; gases
KBPOKT OF DIRECTOR OF BUREAU OF STANDARDS. 243

in steel ; cooperite and stellite ; literature on steel, iron, and bronzes

;

heat treatment of rivets, bars, and springs ; alloying and refining of

gold and platinum; Monel metal; thermal analysis standards; characteristics of high-speed steels; oxidation of brass; the recovery of

copper from shell cases; utilization of scrap aluminum; practical

welding; copper-lead alloys; manufacture of magnesium; tin-lead

alloys for coating copper; drawing of aluminum sheet; metals for

ship construction ; core oils for foundry sands ; small gas crucible fur- naces; heat-treating equipment; acid-proof iron alloys; manufacture of tin foil; copper-bearing metal; trajisformation-points re- corder; properties of magnalium; furnace fire bricks; open-hearth

special steels; bearing metals for tractors; standard tests for bearing

metals; bario metal; substitution of aluminum alloys for instrument

brass. Problems of Military Interest. The Bureau has developed very close relations with several of the

technical military establishments, including branches of the General

Staff, the Army and Navy Ordnance Bureaus, the Aircraft Production, the Corps of Engineers, the Signal Corps, and the Quartermaster's Department. In particular, and as illustrative of the type of

work in cooperation, may be given a statement I'egarding some of the

problems with which the Bureau is working in coopei'ation with the

technical staff of the Army Ordnance which maintains several men

at the Bureau for work on problems in which they are interested.

Test-Bar Fractures.—The Ordnance Department had accumulated

a very considerable number of fractured test bars as a result of an ex- amination of many thousands of samples of steel, and it was thought

desirable to make a statistical and systematic study of the fractures

produced in tension, methods of photographing, and an explanation

and description of the various characteristic features by relating them

with the structure of the tension bars. The aim is to embody the re- sults of this work in the form of a manual which may be furnished

to inspectors.

Hardness of Brass Cartridge Cases.—Another problem is the in- vestigation of the hardness of brass cartridge cases by means of the

micro-Brinell-hardness machine developed by the Ordnance Department during the war. The hardness study will be supplemented by

a study of the microstructure of the material, determination of mechanical properties, mainly in tension, and their behavior as regards

corrosion cracking. The aim is to supplement the various descriptive tests now made of brass cartridge cases. A considerable amount

of work was also done b}^ the Bureau in the examination of cartridge

cases during the war, for the purpose of finding the effects of various

methods of manufacturing upon the properties of the finished material and with a view to aiding the Ordnance Department in its in- spection and specification service. Machine-Gun Erosion.—A systematic study of this subject is being

made from the metallurgical point of view including the preparation

of a considerable number of special steels, determination of the in- teresting physical properties, and the ballistic tests, which last are being conducted by the Ordnance Department itself. Copper Crusher Gauges.—At the request of the Society of American Manufacturers of Small Arms and Ammunition and of the Ord-
244 EEPOET or DIRECTOR OF BUREAU OF STANDARDS.

nance Department, the Bureau has been actively engaged in the preparation of specifications for copper crusher gauges for testing ammunition and standardizing the method of use. A considerable

amovmt of work has also been clone on the characteristics of the

copper crusher cylinders, particularly as related to their properties

under various conditions of annealing and as dependent upon their,

"conditions of recompression, and includes a study of the resulting

errors. Several conferences have been held, and it is expected

shortly to close this subject.

Centnfugal-Steel Castings.-—It was considered desirable to study

the properties of ingots cast by the Millspaugh centrifugal method.

This method produces an ingot of hollow cylindrical form, and it was

thought that there would be a considerable saving of material, labor,

and time in the manufacture of cylindrical steel appliances. If the

method warranted, it was hoped to be able to substitute cast or heattreated cast material made by this centrifugal process for forged

pieces. The castings submitted for examination were a miscella- neous assortment of four of several chemical compositions and cast under various conditions, but none of the cylinders being cast

strictly in accordance with specification requirements for ordnance

material. Very interesting and promising results were obtained.

Segregation of the elements—carbon, sulphur, and phosphorus

appears to exist only radially and is confined mainly to a very thin

layer of the inner zone, but exists also slightly in the outer zone. Nickel also appears to segregate somewhat, following the carbon.

The maximum carbon segregation found amounted to 0.09 per cent

in a steel containing 0.66 carbon and nickel 2.2 per cent. Blowholes

appear only in the inner segregative zone. The density across a sec- tion is practically constant; tensile and shock tests show in general

greater strength and elasticity, but less ductility in tangential than

in longitudinal directions. This method of casting develops very

slight intei'nal stresses. By suitable heat treatment the physical

properties of steel cast by this method compare very favorably with

forged material of the same composition. The metal of the casting

is clean and sound and its microstructure better than in ordinary

types of steel casting. Magnesium, Aluminum Alloys for Mirrors.—The Signal Corps and

the Corps of Engineers were much interested in the development of a

light metallic mirror material of high-reflecting power, and it was

desired, if possible, to realize mirrors of diameter up to 6 feet. The

Bureau undertook the investigation of aluminum-magnesium alloys

for mirrors, and although it was found impracticable to build such

large mirrors it was found that the compound AljMg^, containing

50 per cent magnesium, gave a reflection of 85 in the blue and 93 in

the red and that this could be made mechanically satisfactory by a vacuum melting and heat treatment. Although this alloy resists action of dilute acids and alkalies much more than any other AlMg

alloy that has come under our observation, it is not recommended

where permanency is of prime importance, as some of the samples

showed evidences of slight contamination after standing several

months in the laboratory.

Corrosion of Aluminum Alloys.—One of the problems in which

the National Advisory Committee for Aeronautics and also the Navy

Department were gi'eatly interested is the effects of corrosion, partic-
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 245

ularly under sea-water conditions, on aluminum alloys such as those

used in airplane manufacture. A systematic program of experiments and exposure tests have been started and is still under way.

A number of the alloys covered with various protective coatings, to- gether with unprotective sheets, are being exposed to the action of

the atmosphere and sea water at three widely differing latitudes to determine the best alloy and coating to be used in seaplane construction. Steel Helmets for the United States Army.—Some work was carried out for the National Research- Council in connection with cer- tain problems arising in the manufacture of steel helmets

:

(1) To determine whether heating up to quenching temperature

in the heat treatment of helmets following the pressing operations was sufficient to remove the stresses set up during the pressing. The

average results of tests showed that heating of test pieces of helmet

steel to 825° C. and cooling quickly in a furnace reduced the amount

of stresses by about 60 per cent, while those test pieces heated to a

like temperature and cooled slowly in a furnace showing a reduction

of some 73 per cent as compared with the amount of stresses found

present in the test pieces which were not heat treated; that is, in the original or pressed condition.

(2) l5etermination of length of time needed to hold helmet steels at the quenching temperature to get full hardening on quenching.

Helmet steels of 11 compositions were also examined to determine

their critical ranges in connection with the development of tests for determining resistance to deformation and penetration.

Effect of Prolonged Annealing High-Silicon Cast Iron {Dunron) .

The Inspection Division of the Ordnance Department, which was in- terested in the use of noncorrodible iron of the type of " duriron " (cast iron of the approximate composition—total carbon, 1.18 per

cent; graphite, 1.09; silicon, 13 per cent) —requested the Bureau to determine the possibility of any changes in composition upon con- tinued heating. The examination showed that continued heating for

as long as 50 hours at 1.000° C. produced no essential change either

in structure or composition.

Horseshoe lYails.—At the request of the General Engineer Depot,

United States Army, an examination was made of nails representative of most of the manufacturers of this type of material, with the

aim of drawing up specifications. The examination showed a rather

wide variance in the type of steel used (0.07 to 0.20 per cent carbon)

in the process, some being hot forged, others cold-stamped. A simple type of impact test using a notched specimen was recommended

for determining the relative merits of different types of nails. Deterioration of Nichrome Castings Upon Heating.—The attention

of the Bureau was called to this problem by the Chemical Warfare

Service. The large nichrome castings in the form of tubes used for

the production of charcoal for gas masks deteriorated rather rapidly

in service, becoming weak and Ijrittle. The examination made of the

material showed that, contrary to the opinion expressed by other in- vestigators of this problem, the deterioration does not consist in

the formation of a carbide by interaction with the charcoal. On

the other hand, the carbide normally present in the nichrome is re- moved. An intercrystalline brittleness, apparently identical with
246 REPORT OP DIRECTOR OP BUREAU OP STANDARDS.

that of nichrome wires upon continued heating, is produced, the exact nature and cause of which have not yet been determined.

The Relative Cutting Properties of " Cooperite " and " StelVdeP—

At the request of the Bui-eau of Ordnance, Navy Department, a test was undertaken to show the relative cutting properties of the two

alloys " stellite " and " cooperite." These two alloys, though quite

different in chemical composition, have very similar mechanical properties ; they are very hard and able to " keep an edge " at a rather

high temperature. They are used, particularly stellite, quite extensively to replace and supplement high-speed steel tools for cutting.

Cooperite is essentially an alloy of nickel and zirconium with appreciable amounts of iron and silicon. Stellite, which is manufactured in several different grades, is a rather complex alloy, the es- sential elements of which are cobalt, chromium, tungsten, and

molybdenum.

The series of service tests made showed that cooperite is but slightly

inferior to the better grades of stellite. Lathe tools made of cooperite failed after a cut of -i-inch lengths made on a 5-inch round of

nickel-chromium steel under the following conditions: Speed, 226

feet per minute; feed, 0.0135; depth of higher speed, 240 feet per

minute; the other conditions being the same, but for a length of 8

inches before failure occurred.

Defects in Shrapnel Steel.—At the request of the inspection division. Ordnance Department, an extensive and detailed study of the

defects in steel slugs intended for the manufacture of shrapnel cases, as revealed in the fracture by the " nick-and-break " test, was made.

This Avas suj^plemented by a study of slugs which had been sheared

as well as broken by the "nick-and-break," the aim being to show

whether shearing could be substituted for the latter method in the

work of inspection. The results of the examination, however, did

not appear to warrant a recommendation from the Bureau for the

proposed change in the method of inspection of this class of materials.

Light Armor Plate.—In cooperation with the Bureau of Mines and

the Navy Department the Bureau is studying the properties of special

alloy steels suitable for the development of light armor. The

majority of these steels contain zirconium, while others contain

molybdenum, boron, cerium, etc. About 150 ingots have been made

by the Bureau of Mines Experiment Station at Ithaca, N. Y., and

have been rolled into plates of three-eighths or one-half inch thick- ness at the Bureau of Standards. The properties of these materials

are being thoroughly examined, including mechanical properties,

heat treated and annealed, hardness, resistance to impact, microstructure, chemical analysis, and thermal analysis. In conjunction

with the ballistic tests to be made by the Navy Department valuable

and useful data will be obtained for the design of light armor plate.

Liquid Forging of Light Aluminum Alloys.— Morris engineering process was investigated in cooperation Avith the Naval Gun

Factory. This process gives a highly satisfactory alloy for aeroto cast or die-cast metal, being of increased strength and ductility

and free from blowholes and other imperfections.

Corrosion of Aluminum Carburetors.—This is a problem in which

the Aircraft Production Bureau was very much interested. Its importance lies in the fact that particles of sludge resulting from the cor- rosion taking place in the float chambers of aluminum carburetors
REPORT OF DIRECTOR OF BUREAU OF STAISTDARDS. 247

lodged in the atomizers and stopped the flow of gasoline. The

relation of the composition of cast aluminum to corrosion is being

studied, and various protective coatings are being investigated.

MisceUaneous.—Another problem on which some work has been

done is an examination of causes of failure due to excessive stress developed in certain parts of the Browning machine gun; as, for

instance, bottom plates which split under impact. It would appear

that heretofore an inferior grade of steel has been used for this

piece.

The Bureau of Aircraft Production was interested in finding a

solder of intermediate melting point. A satisfactory special solder was developed by the Bureau of a melting point of approximately

400° C. Its composition is 40 silver, 40 tin, 14 copper, and 6 zinc.

'

RESEARCH AID TO MANUFACTURERS.

It is the policy of the Bureau to aid manufacturers in the solution of their technical problems, and the following list of investigations will give an idea of the kind of help that it has been possible

to render during the past year. This list does not include all the

items of such nature, but those given are typical.

Manufacture o£ Collapsible Tin Tubes.

At the request of one of the large manufacturers of this class of

material, the Bureau undertook the investigation of certain defects

which often occur on the surfaces of such tubes. These defects consist of discolorations, which interfere seriously in the use of light

enamels on such tubes. The study made of this problem, which

included a conference with the manufacturer at the plant, showed

that one type of surface stain was clue to sulphide fumes, the effect being localized and accentuated at certain spots by traces of acid in

the perspiration of the hands touching them. Other surface defects,

usually as streaks, were pointed out as due to contamination with

free sulphur, some of which occurred in the compound used for

lubricating the disks from which the tubes were extruded.

Annealing of Hard Cold-Worked Nickel-Brass.

As part of the study made by this Bureau of metals suitable for

cliaphrag-ms of various types of aeronautic pressure instruments the

behavior of cold-worked nickel-brass, which is used largely for such

diaphragms, was examined. In the cold-worked sheets the " work

lines " to wliich the hardness is due are very pronounced. Upon

annealing, these " work lines " are gradually erased ; heating for 20

minutes at 500° C. is sufficient to remove them entirely. The disapl^earance of these lines or bands mnj be taken as an indication of the

rate at which the hardness due to mechanical working is removed.

Above 500° C. the nickel-brass increases rather rapidly in grain size and becomes soft and ductile.

Copper-Lead Bearing Metals.

Several samples of alloys of lead and copper proposed for use as bearing metals have been submitted for examination. The lead content in some is as high as approximately 50 per cent ; for example, in

"ulcoloy." Lead and copper do not alloy to any appreciable extent;

the resulting mixture of the two elements is a

" sponge " of copper
248 EEPOET or DIRECTOR OF BUREAU OF STANDARDS.

the interstices of which are filled with metallic lead. The size of the

lead globules, which is dependent upon the rate of cooling and the

mechanical agitation, determines largely the efficiency of the metal

for use in bearings. The principal objection to the lead-copper

bearing alloys appears to be the difficulty of reproducing the struc- ture upon remelting for pouring.

Deterioration of Zinc-Aluminum Die-Casting Alloys.

The behavior of an alloy of the composition—zinc 83.4 per cent,

aluminum 15.2 per cent, copper 1.4 per cent—was studied in a series of tests which were chosen so as to approximate the extreme conditions of service.

Immersion in water causes no appreciable change in the alloy, nor

does dry heat, at least up to 100° C. Moist heat (100° C), on the

contrary, produces a pronounced swelling of the specimens in as short a time as six days. An increase of 7.7 per cent in one of the

dimensions of the specimens occurred in 12 days, and the surface of

the allow became covei-ed with " alligator " cracks. Evidently this

alloy, which may be taken as typical of aluminum-zinc alloys of high

zinc content in general, can not be relied upon for die castings in

hot, moist climates. '

Sterling Silverware.

The advice and help of the Bureau was requested by one of the

large manufacturers of silverware during the past year concerning

two different types of defects which appear at times on the surface

of the finished article. Though not serious, these imperfections iml^air the high finish and polish which are desired for this class of

materials. One type of spot occurs upon standing, and appears to be due to tiny inclusions of the cyanide bath used for annealing;

other discolorations are due to surface oxidation of the copper, which

is intentionally' added to silver to harden it. Sharpness Standards.

At the request of manufacturers of razors and cutlery, an attempt

is being made to devise methods for measuring and defining sharpness of fine cutting edges. This is practically a new field of research,

and there is little or no available or published experience to serve as

a basis. MICROSCOPY AND STRUCTURE.

Protective Metallic Coatings for Rustproofing Iron and Steel. The results of the Bureau's experience in the study and testing

of coated metals, together with a resume of a study of the available

technical literature, have been embodied in Circular No. 80 of the

Bureau series. The frequent inquiries for reliable information

along this line rendered the circular a necessary one. The Bureau, in cooperation with a committee of the American

Society for Testing Materials, has been carrying out an extensive

program on the investigation of the properties and testing methods

as applied to zinc-coated metals. An extensive series of exposure

tests of such metals is being arranged.

Nickel Spark-Plug Electrodes.

A study of the deterioration of the nickel terminals of the spark

plugs used in internal-combustion engines was made at the request
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 249

of one of the large manufacturers of this type of material. The

study was extended to include other types of plugs. The brittleness

which results in the electrodes upon usage was shown to be a

characteristic property of nickel wire and must be expected to occur

to some extent in all types of plugs. Deterioration is much more

rapid in some types than in others, due to the stresses to which the

wires are subjected while hot. These stresses, in turn, depend upon

the arrangement and shape of the electrodes. The results of the

study will appear as a Bureau scientific paper.

Cements for Spark-Plug Electrodes.

The use of cements for welding electrodes to spark-plug porcelains has been found to be attended by various difficulties in hightemperature engines such as are used in airplanes. Among these

difficulties are promotion of oxidation and destruction of electrode

wires by reactions taking place in the cements and between the

cement and electrode wires; breaking of porcelain caused by differ- ence in coefficients of thermal expansion of electrode wires and

porcelain ; and the cracking of cement with consequent gas leakage,

due to the same cause . A cement composed of silicate of soda

and raw kaolin has been found to give little trouble from chemical

action. In order to avoid the difficulties attending the use of any

form of cement, the use of a mechanical seal at the top of the porcelain has been tried with promising i-esults. Special Steels. As part of the study which is being made by the Bureau of

" zirconium " and other special steels, a study has been started to demonstrate the role which zirconium and titanium play in such

steels in the endeavor to explain the effect of additions of these

elements upon the physical properties of the resulting steel. Corrosion of Nonferrous Alloys.

During the year, at the request of the Navy Department, a comprehensive program for the study of the corrosion of nonferrous

alloys (particularly copper alloys) was prepared. The Navy Department was to assist in this work by furnishing materials and

in arranging for exposure tests in sea water. Due to changed conditions, the material has not been furnished and the work not

started as yet. The subject will be taken up in the near future,

however, it is hoped.

Study of " Deep Etching " of Metals.

A study of the deep etching of iron and steel has been started. The

aim is to show the influence of the various possible factors—chemical

heterogeneity (segregation), physical heterogeneity (variations in

crystal size, presence of intercrystalline discontinuities, etc.), and mechanical heterogeneity (internal stresses, etc.). The study of the

macrostructure of metals has in general received much less attention

from metallographists than the microstructure.

Microstructure o£ Pure Iron and Mild Steel at High Temperature.

An investigation on this subject has just been completed. Its aim

has been to show how much the change in composition of the surface

layer, which usually accompanies heating in vacuo, affects the results of tests made to reveal the microstructure existing at high tempera-
250 KEPOKT OF DIKECTOK OP BUREAU OF STAXDAEDS.

tures. The results also throw some additional light upon the nature of

the composition change of the surface layer, and also the formation of

the surface pattern by which the microstructure is revealed by means

of " heat-relief " etching.

" Flaky Steel." Examinations were made of numerous specimens of defective gun

steel and airplane crankshaft stock Avhich showed this tyj)e of defect. The defect termed "flake" appears as a shining, coarse, crystalline area in the midst of otherwise sound material. The flake, which may

be as large as 1 centimeter in diameter, has the appearance of an intercrystalline discontinuity in the steel and is A-ery often (if not always)

associated with steel which is badly contaminated with slag and similar inclusions. " Flakes "" reduce the ductility of steel, although the

ultimate strength of the material (in tension) is not affected nearly so much. They are particularly iniurious in material exposed to re- peated stresses. The study of this material is being continued, and

particular attention will be given to the effect of forging and heat

treatment upon such material.

Pearlite in Steel. A study is being made of the state of pearlite in selected steels of

varying chemical compositions after they have been subjected to di- verse heat treatments. This is a continuation of some previous re- searches of ]Mes.srs. Howe and Levy. The experimental work has been

jDractically completed, and this will appear shortly as a bureau

jDublication.

Welding Research.

Several national bodies have been interested in furthering our knowledge of means for improving methods of welding. The Bureau

has been working in cooperation with the Electric-AYelding Committee

of the Emergency Fleet Corporation and later with the Eesearch Committee of the American ^Velding Association. The metallurgical division has been concerned with such questions as outlining specifications

for metallographic examination and experimental study of the rela- tions of structure to brittleness in welds; this is being carried out both on material from American manufacture and material furnished

by the British Admiralty. The resistance to corrosion of different

types of welds, including solubility of acids, in which it appears that

the usual types of joints will not corrode faster than a riveted joint, Avas also investigated. The investigation will also include the effects of the presence of gases entrained in welds: the identification and

role of certain constituents considered harmful, such as the nitrides of

iron, and the development of nondestrtictive tests for welds. Incidentally, a considerable ntimber of welds of various tjq^es haA'e been

prepared for plwsical tests. HEAT TREATMENT AND THERMAL ANALYSIS.

During the past year the experimental heat-treating i^lant has

been enlarged. An electric muffle furnace and two gas- fired metal

and salt-bath furnaces have been installed, and, in addition, the

pyrometer equipment for individual units has been changed to a

central-station control. Among the smaller units installed haA'e been an electric salt bath for annealing and an electric tube furnace for
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 251

use in determining tensile properties of metals at high temperatures.

A most important addition has been the construction from designs

of the membei's of the staff of a modified Eosenhain furnace for taking heating and cooling curves. This furnace does away with the

necessity of varying the heating current. Changes in temperature of

the samples studied are produced by raising and lowering the samp)le in the furnace kept at constant temperature.

New Method for Thermal Analysis.

A new method for making thermal analysis was developed. The

usual practice of recording inverse heating and cooling curves is to record with a chronograph the consecutive time intervals. This in- volves the use of a relatively expensive apparatus now difficult to

obtain. It is also necessary in this methocl to count the time intervals from the chronograph sheet, a process requiring one or two

hours. It has been found that these time intervals could be recorded

as accurately and almost as conveniently by two stop watches, which

thus serve as a cheap substitute for a chronograph. By this process,

also, much time is conserved.

# Iron-Carbon Transformations.

Considerable progress has been made in the investigation of the

transformations in pure iron-carbon alloys, and the results so far

obtained have shown some unexpected phenomena of considerable importance. According to the present outline, this investigation will

probably be completed during the coming year. The transformations

in pure iron-carbon alloys are of gi'eat importance, as they form a

basis for determining the effect of the alloying elements used in producing alloy steels, and also in the determination of the effect of impurities normally present in small and varying quantities in plain

carbon steels. An accurate knowledge of the position and character

of these thermal transformations is also of great practical value, as they form a basis for estimating the temperature of the transformations in steels from the chemical analysis, which will eventually

eliminate the necessity for commercial apparatus for this purpose.

A study is now being made of tlie critical ranges of certain nickelsilicon, armor-plate steels in connection with an investigation of the

meclianical propei'ties of these alloys. This work includes the independent effect of both nickel and silicon, and also additions of rare elements in small quantities, on the thermal critical ranges in order

that correct heat-treatment temperatures may be estimated.

A study of the effe-^t of other alloying elements added to pure ironcarbon alloys is contemplated.

Magnetic and Density Tests. As fundamental to the interpretation of magnetic tests on heattreated steels, a correlation of the magnetic properties of a carbon

steel with physical properties and microstructure has been undertaken. Magnetic analysis has recently received considerable atten- tion throughout the country, and it is expected that the results obtained will add considerably to our present knowledge of this subject.

Magnetic tests are also being made on a high chromium steel under

varying thermal treatments to determine suitability for permanent

magnets.
252 KEPOBT or DIRECTOR OP BUREAU OF STANDARDS.

Density determinations are also being made on a sei'ies of alloy

steels to determine which are the least susceptible to dimensional

changes in hardening.

Mechanical Properties.

To throw further light on the effect of varying heat treatments on

the mechanical properties of various structural alloy steels an investigation is now under Avay to correlate the tensile properties with

impact and fatigue values obtained with various machines now in use throughout the country, and also with results obtained from tor- sion and compression tests. Work on what is probably the most

widely used structural alloy steel (3^ per cent nickel) is now in

progress and will be followed by tests on other widely used types.

Tensife Properties at High Temperatures.

There has recently been started, and is now under way, an investigation of the tensile properties of metals and alloys at high temperatures. The practical value of increasing our knowledge in this field can not be described in the limited space available. The first tests planned include determinations of tensile values (including elastic limit) on A^arious grades of boiler plate from room temperature up to about 600° C, bearing on the value of the various grades with ref- erence to interlocal strain in locomotive fire boxes. The results are

also expected to throw further light on the relative value of two

metliods of melting used in the manufacture of such plates. Tests to throw further light on the effect of carbon and various alloying ele- ments such as nickel, manganese, chromium, tungsten, etc., are in- cluded in the original scheme, these latter tests being made in cooperation with the Blue-Heat Committee of the Engineering Division

of the National Eesearch Council.

High-Speed Steels. A study of high-speed steels is being made to (1) throw further

light on their constitution and properties; (2) to develop a simpler

method than now in use for determining the relative value of two

steels as cutting media. The methods now in use or contemplated

include thermal analysis, whereby heating curves are taken on pre- viously quenched samples, and hardness tests made after hardening

and temj)ering at various temperatures. Cooperation from the mills

is expected in this work. During the past year the problem of highspeed steel cutting has been at an acute stage, due to the extreme

need for high-speed steel and to the shortage in the tungsten supply.

This problem has been treated at the Bureau from the points of view

(1) of the development of nonferrous cutting alloys, (2) the substitution of metals for tungsten, and (3) the improvement of high-speed

steel forming practice ; that is, cast versus wrought tool. The Bureau has had the opportunity of carrying out tests on sev- eral types of product, including cast high-speed cutting tools which

in test have shown cutting properties equal to the best wrought tools of similar composition. The extension on a large scale of the use of

cast tools will work great labor and material saving and will result

in lowering the cost of working metals. One of the special products

studied has been cobalt-chrome tool steel, samples of which were

submitted to elaborate tests and found inferior to the better grades

of tungsten steel for high-speed tools. As a lathe tool it gave the
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 253

best results when used for tools in which the cutting edge was not in

continuous contact with the material being cut, as is the case with

milling cutters. It can not be said that a satisfactory substitute for

tungsten in such tools has yet been found. Besides these performance tests an investigation has been in progress on the general problem of the constitution and theory of the much-discussed high-speed

steel and its " red " hardness. Data on several of the physical properties and microstructure of this steel, as affected by various heat

treatments, have been collected, and seem to answer many of the

questions involved.

Gauge Steels. An investigation of the most suitable steels and treatments for the

manufacture of precision gauges, resulting from work originally

carried on for the War Department, is now in progress. The work

includes determination and comparison of resistance to wear, permanence, resistance to corrosion, soundness, expansibility, and economy

under varying thermal treatments. It is expected that this investigation will be completed during the coming year. Metal Diaphragms.

Elastic lag and hysteresis are serious sources of error in the metal

diaphragms and springs used in aeronautical instruments, such as altimeters and air-speed indicators. An investigation is now in

progress to determine (1) the exact nature of these factors and (2) to develop diaphragms and springs which will minimize and possibly

eliminate these effects. DiapJiragms and springs of various metals and alloys under varying thermal treatments have been, and are being, subjected to various

types of loading in order to obtain a comparison of their elastic properties, and also to determine the best metal for such conditions

of service, thereby improving the precision of these instruments.

Material advance is expected during the coming year. Of the numerous nonferrous alloys investigated the most promising for the construction of diaphragms is aluminum-bronze with 7

per cent aluminum content. A study is also being made of the

hysteresis of steel springs and its elimination. The work done to date on elastic hysteresis leads to the probable conclusion that it is caused by overstrain. The theory has been developed in detail. Embrittling of Steel by Cleaning, Pickling, and Plating.

This investigation, which is now nearing a close, was started

originally in connection with specifications for aircraft parts to determine the harmful effects of pickling, cleaning, and plating in

wires, thin rods, and sheets of various grades of steel submitted to

several heat treatments. Experiments with the tensile test as a

criterion failed to measure properly the embrittling effect produced

by pickling. The impact test on notched bars was also investigated,

but it was found that no constant results could be obtained. Alternating-stress tests of 0.30 carbon steel show that pickling in sul- phuric acid reduces the resistance to fatigue by more than 30 per

cent for rods ranging in diameter from one-eighth to three-eighths of an inch. Steel rods three-sixteenths of an inch in diameter and

carbon content varying from 0.09 to 0.87 per cent show somewhat

corresponding reductions in resistance to fatigue. Analogous results
254 EEPOET OF DIKECTOE OF BUEEAU OF STAXDAEDS.

were obtained by the Erichsen test on sheet steel of various thicknesses and hardness. Brittleness gradually decreases at room temperature, but recovery is not complete although hastened by heating.

Brittleness caused by pickling appears to be the result of two effects combined: (1) A temporarj' effect supposedly dependent on hydrogen: (2) permanent effect caused hy roughening or etching action

of the acid. The effect of plating upon material which has been

cleaned, pickled, or sand-blasted has also been studied.

Temperature Measurements in Steel Works.

Oi^portunity was offered during investigation of steel-manufacturing processes, particularly with respect to uses of manganese, to measure the temperatures of various types of open-hearth and elec- tric-furnace baths, and also tapping and teeming temperatures, in

the practice of five steel companies. The results are particularly

interesting, showing the remarkable uniformity of the refining temperatures for steel in the open hearth, both acid and basic. The

electric furnace practice, in so far as temperature was concerned, was found not to differ materially from that of open-hearth practice.

In the five plants examined the bath temperature was found to range in all cases between 1,590 and 1,640° C. Tapping temperatures ranged from 1,540 to 1,695° C, the higher value being for acid

castings. Teeming temperatures ranged from 1,485 to 1,575° C.

PHYSICAL PROPERTIES AND MISCELLANEOUS METALS.

Tin Conservation.

Up to the time of the signing of the armistice the Bureau was

actively engaged in studying methods of conserving tin. Experimental work was carried on in finding suitable solders, bearing

metals, and bronzes containing a reduced amount of tin, and considerable correspondence was carried on with manufacturers and users of these materials. The Bureau also acted in an advisory capacity

to the Bureau of Exports of the "War Trade Board in matters con- cerning the use of tin, and also cooperated with the War Service Association of Manufacturers of Bearing Metals and Solders.

Bearing Metals.

An extended program has been drawn up for an investigation of

bearing metals. Although they are very widely used, there is little specific data in those works which treat of their properties and behavior, and no standard methods exist for their testing. The program will include phj'sical tests at normal and elevated temperatures

of all the commonly used bearing metals, together with actual tests under service conditions. It is doubtful whether much headway can

be made during the coming year on the program, however, because

of the lack of funds and facilities for carrying on the work.

Corrosion of Brass Under Tension.

Twelve samples of drawn manganese-bronze rod have been exposed

to atmos]:>heric and water corrosion, while under known values of

tensile stress, for a period of two years. The results to date are published in Technologic Paper No. 135. and show that, if this type

of material is subjected to stresses at or above the proportional limit
EEPORT OF DIRBCTOK OF BUREAU OF STANDARDS. 255

of elasticity, it may be expected to crack and fail in a relatively short

time.

Strength of Solder and Soldered Joints.

In connection Avith the American Society for Testing Materials ten- tative specifications for solder, it is thought advisable to determine

the tensile strength of the various compositions of solders, and also

of soldered joints of various metals with several different fluxes. Gold-Palladium Alloys as Substitutes for Platinum.

The hig^h cost and scarcity of platinum greatly stimulated, especially during the war, the production of " platinum substitutes " for

various purposes. Of those intended for use as chemical-laboratory ware no alloy of base metal so far tested has been found suitable.

Two alloys of gold and palladium have been placed on the market and

have come into more or less general use. These are known as

" palau " and " rhotanium."

A series of tests has been carried out to determine the suitability

of these alloys as substitutes for platinum in laboratory ware. The

tests consisted of the determination of the behavior of crucibles made

from the above alloys on heating to 1,100 and 1,200° C. in an oxidizing atmosphere and the effect of the various chemical reagents. The

results of tests would indicate that in many instances these alloys

could replace platinum very satisfactorily, thus releasing a large

quantity of platinum for other purposes.

Fusible-Tin Boiler Plugs and Tin Alloy.

To systematize the testing of fusible-tin boiler plugs, the Bureau

has undertaken the study of the effect of small amounts of impurities on the melting point of pure tin. To this end alloys containing small

amounts of copper, zinc, lead, and antimony, respectively, were made

and their melting points determined. The results of the investigation would indicate that the first addition of all of the above metals

lowers the melting point of tin, except in case of antimony, where

the further addition of antimony above 0.1 per cent raises the meltingpoint. The results obtained show that, in testing for purity, the

simple melting-point test can be satisfactorily substituted for the

laborious chemical tests at present used. The study of the effect of

combination of impurities on the melting point of tin is at present

in progress. The results of the first part of the investigation are in press and are to appear in an early number of the Bulletin of the

American Institute of Mining and Metallurgical Engineers.

Storage-Battery Grid Alloys.

Investigation of the properties of antimony-lead alloys for storagebattery grids is at present in progress. The physical properties, such

as the melting point, tensile strength, brittleness, and hardness, are being determined on alloys containing from 3 to 25 per cent antimony.

Acid-Resisting Alloys.

In spite of the success already attained with the use of acid-resisting irons in the chemical industries, there are still factors of difficulty to be overcome. The best alloys, so far as their acid-resisting properties are concerned, contain from 16 to 18 per cent silicon, are very

brittle, and are so very hard that it is impossible to machine them in

any other way than by grinding with high-speed abrasive wheels.
256 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

These points are decided drawbacks against their more general utili- zation, and experiments are under way at the Bureau to improve the

physical properties of the metal and at the same time make it malleable and machinable.

Effect of Degree of Reduction Upon Internal Stresses Set Up During

Cold Rolling.

This investigation was undertaken Avith a view of trying to throw some light on the question raised as to the desirability of using many

light drafts instead of a few heavy drafts in the drawing of brass

condenser tubing and similar materials. The investigation showed

the advantages of using many light drafts.

Solidification of Steel Ingots.

In connection with the ingot research some experiments were car- ried out by means of paraffining wax ingots, made on a small laboratory scale, to determine the effect of rate of pouring and also the temperature of casting upon, (a) thickness of ingot walls formed during

early stages of solidification, (b) height and location of pipe in entirely solidified ingot. The results of this investigation are being

incorporated with other data in a paper for publication.

Working of Metals.

' Opportunity has been given in the past year to use the new metallurgical equipment for working of metals on several problems of

military interest. It is planned to continue a series of investigations

along systematic lines on the working of metals to determine for

the various operations, and for metals and alloys including brasses

and steels of various compositions the best temperature, the proper

amount of reduction and the properties developed by this method

of working, and the intercomparison, for example, of the metals which

have undergone the operations of rolling, forging, and drawing.

Treatment of Pure Nickel.

An endeavor has been made to make ingots of pure nickel without

introducing contaminating gases. The metal is melted in a vacuum

furnace, and attempts have been made to cold forge. It is essential

to remove all oxides; otherwise the ingots will crumble.

Light Aluminum Alloys.

The investigations carried out on light aluminum alloys, both

wrought and cast, outlined in last year's report have been brought

to a conclusion, and have either appeared in print or are in press. This work was done largely after consultation with the Light-Alloys

Committee of the National Advisory Committee for Aeronautics,

and includes an extended study of the heat treatment of duralumin

the mechanical properties and resistance to corrosion of rolled light

alloys of aluminum and magnesium with copper, nickel, and manganese; the constitution and metallography of aluminum and its light

alloys with copper and magnesium; and some tests of light aluminum

cast alloys.

RAILROAD MATERIALS.

The work on railroad materials has been resumed, and considerable progress has been made on several of the investigations, including the heating stresses developed in car wheels, discontinuities pro-
REPOKT OP DIEECTOR OP BTJEEAU OF STANDARDS. 257

ducing failure in rails, annealing practice as related to cast-iron

wheels, investigation of ingot practice and of packing-ring iron for

pistons.

Graphitization of White Cast-iron.

An investigation has been completed on the graphitization of

white cast-iron upon annealing. This problem arose in connection

with other investigations on the properties and characteristics of

chilled-iron car wheels, and in particular the best range of annealing

temperatures. This problem was brought to the attention of the

Bureau by one of the car-wheel manufacturers. The composition is so chosen and the wheel is so cast that the tread and inside of flange

show white iron and the remainder gi-aphitized or gray iron. In

order to relieve the stresses set up during the cooling of the wheel

under drastic conditions, the wheels are piled in pits while red hot

and allowed to cool very slowly. Investigation developed that the

highest temperature at which no graphitization of the tread and

flange takes place is about 720° C, which is also the maximum an- nealing temperature for car wheels. Incidentall3% observations were made which contribute to the theory of graphitization in white iron.

Investigation of Chilled-Iron Car-Wheel Stresses. The investigation of stresses in chilled-iron car wheels caused by

heat from brake action has been nearly completed. A very large

percentage of car-wheel failures are attributed to stresses caused

by heating of the tread by brake action, the central part^or the

hub of the wheel remaining relatively cool. It is the purpose of this

investigation to determine and record for adoption the most suit- able material and design of wheels to resist stresses of this kind.

In this investigation the tread of the wheel is heated by passing an

electric current through a circular resistor insulated from tlie tread.

The wheel remains stationarj-, thus readily permitting the taking

of the necessary temperature and strain-gauge readings. Considerable differences have been found in the behavior of wheels differ- ing in design and weight. Several car-wheel manufacturers have

cooperated with the Bureau, and it is expected that this uivestigation will be published shortly.

Packing-Ring Investigation.

At the request of the United States EailroadAdministration, the Bureau is continuing an investigation of the cast iron used in locomotive

packing rings and similar parts subjected to the action of supei'heated

steam oy correlation of several mileage records furnished by the

Railroad Administration, and the chemical, physical, and metallographic properties as determined by the Bureau. It is expected to gather sufficient information to formulate a specification for this

important material.

Ingot Investigation.

There is practically ready for publication an investigation carried

out with the cooperation of one of the railroads and several of the

steel companies involving a comparison of several types of ingot

and ingot practice, including chemical, physical, and metallographic

surface of the ingots, and of blooms and rails made from them. Of

142289—19 17
258 KEPOKT OF DIRECTOR OF BUREAU OF STANDARDS.

particular interest is the comparison of pi-operties and segregation

of rails made from ingots of the ordinary shape following three

practices common in the United States, and the corresponding propex-ties of rails made from ingots of the Hadfield type with sink head.

This investigation, which will be published soon, will include chemical analysis of split ingots, split rails and blooms, sulphur prints,

metallographic investigation, tensile, hardness, and drop tests. Effect of Sulphur and Phosphorus in Steel for Railroad Materials.

During the war it was found practically necessary to permit the

use of steel for railroad and other materials containing higher

amounts than was considered desirable of the detrimental elements,

sulphur and phosphorus. At the request of the Eailroad Administration, the Bureau is outlining an investigation of sulphur and

phosphorus and the permissible maximum for the various classes of

steel. The question has been under discussion for some time, and

it appears that the specification-making organizations, such as the

American Society for Testing Materials, are lacking in sufficiently exact scientific knowledge to determine in rational terms the fixed

limits of these elements in steels for various purposes. This investigation will be carried out in part with the new equipment now possessed by the Bureau and in part with material submitted by steel manufacturers and the railroads. Some work has also been done on

the effect produced by varying the amount of phosphorus upon

the microstructure and hardness of a low-carbon steel (basic open

hearth and acid open hearth 0.12 per cent carbon and from 0.008 to

0.115 per cent phosphorus) . They had been cooled doAvn through the

range 750 to 600° C. at different rates varjdng from 5 minutes to 4

hours, the steel first being heated to 900° C. in all cases. CHEMICAL METALLURGY.

The work of the section of chemical metallurgy during the past,

year (and previous years) has been concerned mainly with the smallscale production of pure metals and alloys made therefrom. Physical

properties of these alloys and metals are studied in other sections of

the Bureau. Such activities have necessitated many auxiliary in- vestigations. Among these might be mentioned researches in progress on methods for determining the gases contained in steel. It has

been Imown in a general way for a long time that commercial steels contain apiDreciable amount's of nitrogen, hydrogen, and carbon

monoxide, and these gases are believed to haxe important effects on

the breaking strength and other properties of the metal. Such questions can not properly be studied until reliable methods are available

for determiaiing such gaseous impurities and until steels can be made

free from such gases or containing known amounts of them. Accordingly the pure metals and alloys are being melted in vacuum

furnaces, so that the products obtained are practically ^as free. If

desired, varying amounts of any desired gas can then be introduced

into the metal and the effect studied. Another method for removing

gases, or undesirable effects of gases, consists in adding to the molten

metal some other metal or alloy which combines with the gases and

renders them harmless, or else removes them. Such alloys are called " deoxidizers," and the processes involving their use are called " cle-
REPORT OF DIRECTOK OF BUREAU OF STANDARDS. 259

oxidation"; such processes are a vital part of all commercial methods

of making steel. The study of deoxidation and the use of new deoxidizing alloys has formed part of the working program of the

section of chemical metallurgy.

In many cases, unless alloj^s are made under proper conditions,

they are not uniform in composition throughout, and are then called

" segregated." Such " segregated " portions are discovered by

analyses of portions of the nonuniform metal taken in some sys- tematic way. Many segregation studies of this tj^pe have been con- ducted in the section, especially on alloys containing carbon and

manganese. To reduce the time required for such routine determinations, a new method was devised for determining carbon ; this method

not only is shorter than others in general use, but is more accurate. Much of this work has been of importance from a military point

of view, particularly those phases of deoxidation studies having as one of their objects the conservation of manganese in the steel industry.

The standardization of practice in methods of chemical analysis

in the steel industry and of the shape of test pieces used for securing

drillings for such analyses has also occupied the attention of the

section.

The activities in these various groups of work, as well as in some

others, are described in detail in the subsequent sections of this

report.

Alloys and Pure Metals,

The equipment for making electrolytic iron, and melts or alloys

of it by vacuum melting, has been doubled in capacity. A method

has been developed for making pure magnesium oxide by calcining

pure magnesium sulphate at 1,100° for long periods. This method

produces magnesium oxide at much lower cost than by the acetate method previously used. Large quantities of this purified material

are required to make the crucibles used in producing ingots of pure

metals and alloys. A considerable number of ingots of pure iron

and alloys, principally the manganese-iron-carbon alloys, have been

produced during the year. A thorough segregation study of these

alloys has been made, and some use has been made of the Brinell

hardness machine in exploring segregation.

Pure Aluminum. " The apparatus described in last year's report has been used, but

it has been found simpler to supply electrically the heat for maintaining the bath in a molten condition. Due to the extreme fluidity

of the molten cryolite, which causes it to leak from threaded or other joints in the graphite, the design of a suitable container that

will permit the metal to be tapped is much complicated.

Tests of Phillips' Alloy.

A ferrous alloy called " Phillips' alloy " was submitted to the Bureau by a firm in Attleboro, Mass., which made the alloy from ore obtained locally. It was claimed that this alloj^^ imparted valuable

properties to steel. The Bureau made several pounds of the alloy

from the ore and had it added to Tropena's converter steel at the

Naval Gun Factory. None of the remarkable properties claimed were found in the steel so made.
260 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Method for Determining Gases in Steel. The electric furnace described in the previous report has been

tested and found not entirely satisfactory. Electric furnaces with

pure iron, nichi'ome, and platinum resistors operating in vacuo have also been tried. Some successful determinations have been

made using the latter furnace, and it is believed that the furnaces

with carbon, nichrome, or iron resistors will be developed to work

satisfactorily. A Northrup-Ajax high-frequency induction furnace

is now being tested as to suitability for this work.

Determination of Individual Gases.

Methods for determining oxygen—that is, oxides—nitrogen, and

carbon monoxide have been especially studied. The direct determination of nitrogen (by absorption with calcium vapors as cal- cium nitride and determination of the ammonia formed by hydrolysis of this compound) has been further tested with good results. The apparatus necessary for the determination has been still further

simplified. The determination of carbon monoxide by fractional

combustion methods, using such catalyzers as copper oxide, cobalt

oxide, nickel oxide, etc., has given good results, and woi'k on specific

absorbing agents for carbon monoxide is now in progress. Three

])apers dealing with the Ledebur method for determining oxygen

in steel have been comjjleted. Technologic Paper No. 118 is a

critical study of the method, and shows that it can determine only

11 few of the many oxides liable to be present in steel and that such

determinations requii'e such unusual care and skill as to render the

method of doubtful value. A scientific paper now in press deals

with certain fundamental sources of error in the Ledebur method

and shows that jDrobably not over 75 per cent of the determinable

oxides are given by this method. A technologic paper now in press

details work in which an attempt was made to determine by the

Ledebur method the oxygen content of steels deoxidized in various

ways, but no differentiation according to method of deoxidation

could be made.

In view of these researches it is believed that the Ledebur method

is of little value to metallurgists.

Another method which was found to be without practical value was the Gontal method for determining carbon monoxide and dioxide

in steels. The fundamental defects of this method mentioned in a previous annual report (1917) have been confirmed by later work,

which is described in Technologic Paper No. 126. Conservation of Manganese.

Two lines of research initiated during the war are being carried on with a view to economizing in the use of manganese in steel manufacture : (1) A series of alloys of iron, carbon, and manganese, using pure

materials, is being made, and these alloys are to be tested for physical

properties in the heat-treated and annealed condition. With these

data it is hoped that revisions in specifications for certain steels can

be made whereby their residual manganese content can be much

decreased.

(2) An investigation is being carried on in cooperation with the

National Research Council and others whereby substitute deoxidizers.
KEPOKT OF DIEECTOK OF BUREAU OF STANDARDS. 261

such as various combinations of the deoxidizing elements of silicon,

aluminum, titanium, and manganese, will be tried for making steel. The steel so made will be rolled and forged in the Bureau's plant

and then tested for physical and other properties. A small openhearth furnace of 500 pounds capacity has been designed and built for

this purpose.

Electrolytic Carbon Method.

The Bureau's paper describing this method appears as a technologic paper, and it will also be published in the Journal of Industrial

and Engineering Chemistry for September, 1919.

Ladle-Test Ingot Investigation.

The report on this work has been published as an appendix to the

Keport of Committee A-1 of the American Society for Testing Materials. Arrangements are in progTess to continue the work which was

interrupted by the war. Alloy Work.

It is hoped still further to improve the technique of making pure

iron or alloy melts in the following ways: (1) By making crucibles

by the extmsion process instead of pressing into molds, as now practiced; (2) by melting 25 to 50 pounds of electrolytic iron at a time

and forging this to l-|-inch bars, which will then be cut into suitable

lengths and used as charging material for small crucibles used in the Arsem furnace; (3) by continuous opei"ation of both Arsem fur- naces as soon as another heavy current line is installed; (i) by use of

the Aj ax-Northrup high-frequency furnace; (5) by operation of more electrolytic baths for making iron; (6) by attempting to dropforge test bars to shape instead of machining them.

Work on Gases in Metals.

It is believed, as soon as the Ajax-Northrup furnace is operating

satisfactorily^, that very substantial progress will be made. It is also intended to perfect the design of the resistor furnaces which

have alreadj' given some results. Work on Investigating the Deoxidation of Steel. As soon as the small open-hearth furnance is installed it will be

used to melt heats of steel which will be deoxidized with some of the

old deoxidation processes, and also with some of the new deoxidizers

developed during the cooperative investigation with the National

Eesearch Council. Such steels are intended to be tested for rolling

and forging properties, gas content before, after, and during deoxidation, and for the usual physical properties.

Production of Pure Aluminum.

Some experiments will be made in the endeavor further to purify

commercially pure aluminum hy melting it under fluxes of various

kinds. Electrolj'tic experiements with chemical control of bath composition will be continued.

FOUNDRY.

Tlie Bureau's foundry performs two functions, (1) foundry re- search and preparation of metals and alloys for the investigations

of the metallurgical division, and (2) serves as a commercial foun-
262 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

dry supplying castings mostly for instrument parts to the Bureau and

other Government laboratories. The time of the foundrj^ staff is about

equally divided between these two functions. This foundry appears

to be about the only experimental one conducted by the Government and is one of the very few experimental foundries in the country. It serves a vast industry, and its possibilities for growth and

service are very large. It is hoped that, in the near future, it will

be possible to increase both the equipment and personnel to a point

where it will be possible to midertake the investigation of many of

the more urgent foundry problems.

Government Bronze and Its Substitutes.

In extension of the cooperative work of the Bureau of Standards

with the committee on nonferrous alloys there were made up under

identical conditions in five foundries a series of test bars of Government bronze (88 Cu, lOSn, 2Zn) which were then tested at the

Bureau of Standards. A previous five-foundry set of tests of this

type of metal had shown very considerable discrepancies, evidently

caused by differences in test bars and other variations from standard

practice. In the second series care was taken to reproduce as nearly

as possible identical conditions of operation in each foundry, and an

imi^roved test bar was used. The results for two compositions were

as follows:

Number of specimens. Proportional limit. Tensile

strength. Elon?ation

in 2 inches. Reductionin area.

88 Cn, 10 Sn, 4 Zn

5 foundries, 30

88 Cu, 8 Sn, 4 Zn.

5 foundries, 26

12, 200 ±1,600

11,000 ±1,650

Pounds per square inch. 38,900

±.5,250

39, 400 ±4,200

Per cent. 25.3 ±5.9

32.0 ±7.0

Per cent. 21.0 ±4.7

25.0 ±4.6

At the request of the Navy Department additional investigations

have been made of other modifications of the above tj'pe of bronze.

Of nine variations in composition of lead, zinc, casting bronzes con- taining 90 per cent Cu, the most satisfactory had the composition of

90 Cu, 6^ tin, 0.6 lead, and 3 zinc. This composition lias a proportional limit of 12,200±650 poimds per square inch, tensile strength

of 40,700+1,500 pounds per square inch, elongation in 2 inches of

37.6±6.4 per cent, and reduction in area of 34.1zh4:.5 per cent. Substitution of lead above one-half per cent for zinc or tin and of zinc

above 2 per cent for tin was found to have detrimental effects on the

physical properties of the castings. Further work on this series of

bronzes is being continued, and it is expected to be able definitely to map the system of bronzes containing copper, tin, lead, and zinc over

the range of practical interest. New Melting Equipment.

The metal-melting equipment of the Bureau has been augmented

during the past year by the putting into operation of an electric-arc

furnace of a modified tlerault type, of 600-pound capacity, for melting steel and iron, and by the construction of an electric crucible

furnace for melting steel and other alloys, and a small hearth furnace

for melting cast iron. The foundry is now in a position to melt any

metals or alloys used in the making of castings.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 263

Weathering of Art Bronzes.

A study is being made of the relation of the composition of statu- ary bronzes to the facilities with -which they assume patinas on ex- posure to weather. A series of such bronzes has been subject to exposure tests for some three years. This work is being carried out

with the cooperation of one of the statuary manufacturers and with

the advice of distinguished sculptors.

Efficiency Study of Electric Furnaces.

The Bureau has made an efficiency study of one type of electric

melting furnace and has made suggestions for the improvement of

several types of electric metal-melting furnaces. This work will be

carried further, since melting of metals by electricity has become an

important factor in the foundry industry.

Several Types of Metallurgical Refractories.

The possession of a number of types of metal-melting furnaces

heated by a variety of fuels, gas, oil, and electricity enables the

Bureau to collect data on the action in actual service of different

metallurgical refractories under various conditions of heating; the

metallurgical and ceramic divisions cooperate in this work, the re- sults of which, it is expected, will lead to a more thorougli understanding of the properties and adaptability of existing metallurgical

refractories and to the development of new ones. Protective Coatings for Aluminum Castings.

At the request of the Bureau of Aircraft Production of the Army

an investigation of various protective coatings to prevent corrosion

of aluminum castings is being continued. After a satisfactory coat- ing can be found it will have considerable value for industrial uses

also. Experimental and Practical Castings.

The past year has seen a marked increase in service given by the

foundry to the Bureau and the research laboratories of other Government departments in the preparation of a great variety of kinds

and types of metal and alloj^ castings. The value of castings furaished to laboratories was $1,850. Following is a tabulation of the

salient points of this service

:

Metal. Castings. Patterns. Weight

Bronze ". 684

1, 738 432

5868

5

16

18

93 417

169

216

4

1

1

1

1

Kilograms.

648

1,896 554

23 240 381

10

79

1

Brass Al alloy (light) Al bronze Cast iron Lead _ Pb-Sb alloy Copper

Mirror rn^tal German silver

Total, 1919 3,008

2,249

709

516 3,875 Total, 1918 2,455

Investigation of Light Aluminum Casting Alloys.

This type of alloy is of great interest in the airplane and automobile industries, and the object of this investigation was to discover
264 REPORT OP DIRECTOR OF BUREAU OF STANDARDS.

alloys with improved meclianicul properties, the effects of heat treat- ment, impurities, foundry practice, and their corrodibility. The

tensile properties and hardness of a number of light aluminumcasting alloys have been determined, resistance to corrosion compared, and resistance to alternating stresses determined of a few

commonly used compositions. It is possible to obtain an alloy con- taining from 2 to 3 per cent copper, together with 1 or 2 per cent

nickel or manganese, or both, which will have a reasonable amount

of ductility, and it is believed that an alloy of this type should have

commercial value. Mechanical properties suggested for such an

alloy are the following: Tensile stress, 22,000 to 25,000 pounds per

square inch; elongation, in 2 inches, not less than 5 per cent. The

addition of manganese to alloys containing copper reduces, in a marked manner, the ductility, but increases the tensile strength and

the hardness. Annealing at 500° C., followed by several days' aging,

increases the tensile strength and hardness and generally decreases

the ductility. Magnesium appears to increase the hardening effect of

heat treatment. The heat treatment of light aluminum castings would

seem to have commercial possibilities. The salt-spray corrosion test showed no very appreciable difference between the several compositions in resistance to corrosion. A study of the resistance to the

action of alternating stresses of three compositions of light alloys

containing, respectively, (1)8 per cent copper; (2) 12 to 15 per cent

zinc, 2 to 3 per cent copper; (3) 1 to 2 per cent copper, 1^ to 2 per

cent manganese, showed very little difference, all withstanding

10,000,000 complete reversals at the maximum fiber stress of 7,000

pounds per square inch.

Molding-Sand Investigations,

Methods liave been developed for testing sands and clays to determine their fitness for various uses in foundries. In addition to the testing of a large number of molding sands and clays by ac- cepted methods, this work has involved the development of new

forms of apparatus for determining the permeability and the co- hesiveness of sands and for ascertaining the proper amount of water

to use with a given sand. A new and important feature of this in- vestigation is the testing of sands after convei'ting them, by baking,

to approximately the condition of sands being used for making cast- ings. These tests are more instructive than tests conducted on sands

fresh from the quarry, as has been the custom hitherto.

Considerable work has been done in connection with the recovery

of sand from the waste-sand heaps of steel-casting foundries. Tests

have shown that it is possible to reclaim for further use a large proportion of the sands now being discarded.

A bulletin on the methods of testing sands and on the recovery

of usable sand from what is now considered waste material is now

being prepared.

New Type of Volumeter.

A new type of volumeter for accurately measuring the volume of

bodies of irregular shape (such as sand, etc.) has been devised and

its limits of accuracy derived. The principle of the apparatus is the displacement of a liquid upon immersion of the solid and the

measurement of the amount of liquid displaced by noting the rise
EEPORT OF DIRECTOR OF BUREAU OF STANDARDS. 265

of liquid in a long slanting tube of small bore. The advantage of

this apparatus is that it is very rapid in operation and measures volumes to 0.01 cubic centimeter, while the accuracy obtainable with

other types of displacement volumeters is limited by the size of one drop of the liquid used, approximately 0.05 cubic centimeter. Tliis

apparatus has many possible applications in testing and research

work.

9. CERAMICS.

[Development of new uses for clays; replacement of imported by native materials; improve- ment of quality of products; designing and conducting tests for quality; standards of quality; routine tests for Government purchases; acting in advisory capacity as to conservation of

' fuel and transportation for ceramics; acting as clearing house for collection and dissemination of information.] CLAY PRODUCTS.

(Investigation of building tile and other clay products ; industrial and educational co- operation ; design of new equipment ; development of enamels for iron and copper ; studies

of kiln efficiency ; new uses for cJay products ; improvement of quality of products ; manufacture of certain porcelains for Government use.) Standardized Clay Tests. Considerable work has been done during the past year in cooperation with the conxmittee on standards of the American Ceramic

Society in its endeavor to establish uniform methods for the testing

of clays. Check determinations have been made and several devices

designefl for use in this connection.

Refractories.

The general subject of refi'actories has received continued attention. Definitions covering the general requirements of clay refractories have been proposed and adopted as tentative specifications by

the American Society for Testing Materials. Work is in progress on a modified method of determining the softening point of refractory materials. Tests invoh'ing the estimation of the softening point, resistance

to load, and the chemical composition have been made throughout

the year for the Panama Canal, several navy yards, and other departments of the Government.

Two technologic papers dealing with the subject of silica refractories have been published.

Considerable work has been done in cooperation with three manufacturers dealing with the development of improved blocks for glassmelting tank furnaces. The importance of this subject justifies vig- orous effort. The results so far obtained are encouraging and indi- cate that the study has been pursued on sound principles, but trials on a large scale are required to verify the facts so far ascertained.

A very satisfactory white furnace cement to be applied upon the

exterior of furnace walls or to be used as a mortar has been developed.

Light-Weight Refractories.

The new type of refractory proposed by the Bureau last year, combining light weight, porosity, good heat-insulating quality, and high

refractoriness, has aroused considerable attention, with the result

that several companies have undertaken its manufacture. There is eyerj reason to believe that this type of material will find application

in connection with marine-boiler installations, furaace crowns, kiln

blocks for terra cotta, and other wa^es.
266 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Refractory Porcelain.

Further progress has been made in the production of the heatresisting materia] known as Marqiiardt porcelain, formerly imported

from Germany, and it has been found possible to produce pyrometer

tubes over 7 feet in length. A technologic paper on this subject is in course of preparation, and a similar contrilbution has been submitted to the American Institute of Mining Engineers to be read at the September meeting, 1919. Assistance has been rendered to three

plants engaged in the manufacture of Marquardt porcelain. The

necessity of firing to a temperature of not less than cone 16, and preferably 18, has been pointed out. Sillimanite Refractories.

Tubes and other shapes of commercially pure sillimanite f AI2O3.

SiO,) coraioosed of 102 parts of anhydrous alumina and 258 parts of

kaolin have been made and have proved satisfactory.

American Crucible and Glass-Pot Clays.

A technologic paper dealing with this subject has been submitted

for printing. It comprises a careful study of the physical properties

of a number of high-grade domestic clays compared with two wellknown German clays. At the same time the principles involved in

the construction of crucible and pot bodies are discussed.

Porcelain Glass Pots. The porcelain and semiporcelain pots worked out for the melting

of optical glass have been thoroughly tested out in several hundred

melts and have proved very successful. The best porcelain composi--

tion has been found to be as follows:

Per cent.' White-ware bisque, througli 10-mesh sieve 48 Tennessee and Kentucky bnll clays 23 Kaolin 24 Feldspar , 5

Total . 100 The white-ware bisque is waste material from earthenware and

. wall-tile plants.

Casting Process. The process of casting glass pots and other heavy clay products has

been steadily improved and has been extended to the making of closed

pots. Further developments are under way in cooperation with two

manufacturing establishments.

Study of Spark-Plug Porcelains.

The results of a large number of experiments with 195 porcelain

compositions have been analyzed and described in Eeport No. 23,

Aeronautic Power Plants. Similar reports will be published as a Bureau publication and in the Journal of the American Ceramic

Society.

One of the best porcelains, showing high electrical resistance at a temperature of 690° C. and good mechanical qualities, has the fol- lowing composition

Per cent. Per cent. Georgia kaolin 10 Calcine No. 19 40

Florida kaolin 10 Calcine No. 14 20 North Carolina kaolin 10 Delaware kaolin 10
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 267

The compositions of the calcines are

:

Calcine No. 14, Calcine No. 19. Calcine No. 14. Calcine No. 19.

Per cent. 56.00 Per cent. 70.20 27.80

Potter.s flint Per cent.

25. 80 Per cent. Anhydrous alumina 2.00 Magnesium carbonate 18.20

The minimum maturing temperature of this porcelain con-esponds

to cone No. 16, or approximately 1,450° C. The calcines Nos. 14

and 19 require 1,390 and 1,530° C., respectively, for proper calcination. The use of this type of porcelain is being extended to products

other than spark plugs, where high electrical resistance at elevated

temperatures is required, such as heating devices, insulators for the

Cottrell process, etc. Use of American Clays in White-Ware Pottery.

The cooperative work conducted with the United States Potters' Association in 11 plants at East Liverpool, Ohio, has been completed. The object of the investigation was to make pottery entirely from American clays under commercial conditions. It has

been shown that tableware of excellent quality can be made from

domestic materials. Of the 46 compositions more than one-half

proved to be satisfactory.

Terra-Cotta Bodies and Claj's.

An exhaustive study of practically all clays and prepared mixtures used in the manufacture of architectural terra cotta is under

v/ay and is rapidly approaching completion. The work embraces

the study of the porosity and volum^e changes shown by the materials at different firing "temperatures, their mechanical strength as estimated by the transverse test, and their resistance to the disrupting action of crystallizing sodium sulphate. In this manner it is expected to establish the minimum temperatures to which the materials must be fired in order to possess the required strength. At

the same time, the peculiarities of the clays and bodies from differ- ent parts of the country will be set forth. Hard-Fire Porcelain.

' The elaborate investigation of hard-fire porcelain begun three

years ago is approaching completion. More than 300 compositions

have been studied with reference to porosity and volume changes

at different temperatures, the points of vitrification and overfiring,

mechanical strength, tendency to deform, coefficient of expansion,

and other physical constants. Several thousand pieces of tableware,

plates, cups, and saucers have been glazed and fired. It is believed

that this work will shed much light npon aspects of hard-fire porcelain m^anufacture which have been overlooked, and will contribute toward placing our knowledge of this subject on a firmer

basis. Several one-fire porcelain compositions have been developed with

u pleasing glaze Avhich have been applied successfullj^ in several

potteries.
268 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Cooperative work has been done also in connection with the manufacture of hard-fire porcelain for use in the textile industry.

Clay Tests. Approximately 300 tests of clays, fire bricks, feldspar, flint,

whiting, and other ceramic materials have been made for Government departments and the public.

Scientific and Industrial Cooperation.

Cooperation is being maintained by the Bureau with many firms

and individuals with reference to industrial problems, both by corre- spondence and consultation.

A large amount of work is being done also in cooperation with

the scientific branches of the Government, the Nati(>nal Research

Council, the American Ceramic Society, the National Terra Cotta

Society, the United States Potters' Association, the Eefractories

Manufacturei's' Association, the American Society for Testing Materials, the National Brick Manufacturers' Association, etc. Equipment of Ceramic Division in Industrial Laboratory.

The contracts for the construction of new furnaces and kilns have

been let, all of the machinery and apparatus purchased, and the

installation of the equipment begun.

Enameled-Metal Products.

A section devoted to this branch of industry has been formally

organized and has begun its activities in a vigorous manner. Two

technologic papers dealing with the principles of iron enameling are being printed. The researches under way are concerned with diffi- culties encountered in the manufacture of enameled cast iron and steei products.

Several enamels adapted for application on copper have been

worked out, which replace similar compositions foi'merly imported

from Germany.

Zircite Refractories.

Fire bricks made from zircite ore cemented by means of ball

clay have been made for the Washington Navy Yard.

Zinc Spinel.

A study has been made of the proper temperatures required to

calcine mixtures of zinc oxide and alumina to form crystalline

ZnO.ALOg, which is used as an opacifier in enamels and glazes,

replacing the expensive tin oxide. Likewise, the use of different sources of zinc oxide and alumina, such as zinc carbonate and

hj^dratecl alumina, were investigated.

Tennessee Ball Clays.

The effect of washing Tennessee ball clay, represented by 15 samples, has been studied by determining the residue left on the lawn,

the volume shrinkage, and the strength of the dried clay, the color

and shrinkage of the fired material. The purpose of this work was

to show whether refining of the material by washing is justified.

Investigation of Brick Piers.

The complete data of this investigation, covering the discussion of

the results of tests on 50 piers 2^ by 2^ by 10 feet high, has been pub-
KEPOKT OF DIRECTOR OF BUREAU OF STANDARDS. 269

lished since the last report. The demand for this report has been

so extensive that it has been necessary to issue a second edition.

An abstract of this investigation was presented in the last report.

Investigation of Strength of Hollow-Tile Walls.

Material Used.—^The tiles used in the construction of the walls were

furnished through the courtesy of the National Fireproofing Co.

The results of determinations of the physical properties of the tile have already been published in Technologic Paper No. 120, the speci- mens being from an Ohio plant. The data obtained were chiefly

the compressive strengths and absorption properties. About 250

tests were made. The strength, moduli, and hardness results were

correlated with the results of absorption tests. It was found that the

strength of the tile, when tested on ends, averaged about 7,500

pounds per square inch of net cross-sectional area, with a variation

from 4,500 to 12,000 pounds per square inch between the minimum

and maximum results obtained for the series. The compressive

strengths and moduli of elasticity varied approximately inversely

with the capacity to absorb water. The absorption varied from 4.4 to 10.9 per cent, with an average of 8 per cent. Through the joint

cooperation of committee C-10 of the American Society for Testing

Materials similar tests were conducted by various laboratories with

different geological locations. The ceramic properties of the clay

influence the behavior of the finished product and depend on the

location. Through the correlation of the results with those of the

other laboratories—all data being selected in accordance with the same general program—it is believed important information has been

furnished for writing building-codes specifications as regards this

commodity.

Descriftion of Walls Tested.—There were 32 walls constructed for

test purposes according to the folloAving specifications: The walls were 4 feet Avide by 12 feet high and thicknesses of 6, 8, and 12

inches, depending on the dimensions of the tile. The tile for 24 of

the walls were selected from an Ohio plant and those for the re- maining walls from the Perth Amboy (N. J.) plant of the National

Fireproofing Co. The compressive strengths of the walls were determined with the flues running vertically in one series of tests, in another with the flues running horizontally, the load being applied

concentrically with the axis of the 10,000,000-pound testing machine.

Similar tests were carried out to determine the effects of applying

the load eccentrically to approximate the behavior of joists and

floor loads. Further tests also were conducted on the strength and

absorption of the individual tiles. The results obtained are, in brief, as follows: The average loads

for the 6, 8, and 12 inch walls of Ohio tile, flues vertical, under concentric loading, were 297, 408, and 543 in thousand-pound units,

respectively, and about half these values when the flues were placed

horizontally. The Perth Amboy 6 and 12 inch walls withstood much

lower average values—that is, 137 and 241 in thousand-pound units,

respectively—when flues were vertical and 42 and 70 in thousandpound units Avhen horizontal.

There was a marked reduction in the strength of the walls as a

result of eccentric loading, and in several cases the failures were

local at point of loading, in which case the walls were retested

under concentric loads, as before.
270 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

It was originally the intention to cany out the tests in accordance

with the program covering geographical districts, so as to be repre- sentative of the entire national output. War conditions made this

impossible on account of the lack of transportation facilities. But,

since there are now numerous results of tests of tile from different

districts tested in concert, it may be assumed that the ratio of

the strengths of single tiles to those of walls will be proportionately

the same in the various districts as has been found for Ohio and

New Jersey.

All the tests have been completed, and the results are being prepared for early publication.

Architectural Terra Cotta. The study of the properties of this nuiterial has been continued

during the year with xerj gratifying results. More attention was

paid to the examination of the material in service on buildings for

various periods of time. Two very striking types of failures were

encountered, both due to lack of knowledge of the projoer use of

terra cotta. The first type is that where the glaze is forced away

from tile body. This is apparently due to improper protection of

the unglazed portions from contact with moisture, such as " backing

up" free standing work with soft brick, or lack of flashing or waterproofing edges or joints of this type of work. The second type is due to improper methods of attaching the terra cotta veneer to the

structure and is shown by actual crushing of the terra cotta. These

examinations force one to the conclusion that too many failures are due to a lack of proper knowledge of the use of otlierwise satisfactory materials. This applies to other veneers, especially stone,

which is used so much on the exterior of lower floors of structures Both granite and limestone were found which had failed either in

com]:)ression or shear.

Tlie laboratory' part of the work consisted in making test pieces

for absorption, artificial freezing, and transverse-strength determinations from the various clays and bodies used by the majority of

the manufacturers of the country. These test pieces were burned at seven different temperatures. With the collation of the data obtained from these, a final report will be prepared during the coming year, covering all the work done hj the Bureau on this interesting and valuable decorative material.

Fire Tests of Concrete Columns.

In this investigation, 28 full-sized building columns of reinforced

concrete liave been made, 25 have been subjected to the combined

fire-and-load test, and 7 have been tested cold, in compression, in

the 10,000,000-pouncl testing machine. A complete description of

this work will be found in the report of division 3. Determination of Lavs^s of Earth Resistance.

This research was inaugurated in cooperation with the soils committee of the American Society of Civil Engineei"s and has been

briefly discussed in the last report. The matter has already been

given considerable attention by the Bureau in the field of electrolysis mitigation and the related problems in soil resistivity. The pres- ent investigation has dealt entirely with the corresponding problems

involving the laws of mechanical resistance to strain as a result of
BEPOKT OF DIRECTOR OF BUREAU OF STANDARDS. 271

the presence of engineering structures in earths—piers, foundations^

piles, retaining walls, etc. It has been the aim to ascertain the laws

which condition or control engineering practice and to give the

proper d^'namical interpretation of these laws in accordance Avith

the accepted principles of physics. It has been found experimentally

that the behaviors of soils are conditioned by their structures. This

fact has largely been ignored in soil analyses. It is therefore neces- sary to conduct fundamental investigations to determine these struc- tures and the laws of transmission of matter, energy, momenta, stress, or other entities as influenced by them. The cooperating committees

have given attention primarily to the classification of soils, the propei"

hypothecation of structures in conformity with statistical mechanics,

the devising of apparatus for field and laboratory measurements,

and the conducting of individual tests to determine the actual properties and behaviors of a great variety of soils. It has been found

thus far that the problem of soil behaviors admits of a complete

scientific statement and direct correlation with other physical science.

In several cases the mechanical behaviors have been found to corre- spond very closely to analogous results found in the related problems

in the various branches of physics. In other cases the predictions

and contentions of scientific inves,tigators as to the impracticability

and irrationality of the older theory of earth resistance, as previously

formulated, are sustained by experiments.

On account of the surmounting of certain mechanical difficulties which have been encountered from time to time in experiments and

the labor involved in the dynamical interpretation of the various

data it has been impossible to complete the final report at this time.

Several reports have been published by the soils committee of the

American Society of Civil Engineers, which contain the results of

the preliminary and earlier experiments made by the Bureau. The

final report on the investigation is being prepared for publication.

General Tests of Structural Materials.

The following tests not classified in reports of researches have

been made for various departments of the Government and different

manufacturers. These include 57 tensile tests of wire ropes rangingin diameters from three-eighths to 1| inches, including the preparation of most of the specimens for tests, for use by the Government at the Isthmian Canal; 34 tests of Manila rope ranging in diameters

from three-fourths to 4 inches; 1 test of a steel hoisting sling for

derricks ; 4 tensile tests of sheet aluminum ; 4 determinations of the

elasticity_ of special spring steel ; and 8 tests of sand-lime brick for

compression and bending.

A number of tests were conducted for the underwriter's laboratory,

as follows: Determination of the compressive strength of 3 reinforced-concrete columns and 9 timber columns, including moisture

percentages; 20 bricks and 100 building tile tested transversely to ascertain the flexural strength.

The following tests were made for different departments of the

Bureau of Standards : (1) For the cement section : Four hundred and

forty-four transverse tests of 1-inch square bars of sorel-cement

flooring material 11 inches long; 297 compressive-strength tests of

6-inch concrete cylinders 12 inches long; 980 similar tests of 2 by 4

inch cylinders of sorel cement; 385 compression tests of 2 by 2 inch

cubes of cement. (2) For the fireproofing section: Seven concrete
272 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

columns 12 to 18 inches in diametei' by 9 feet for compressive

strength ; 133 cement cj^inders in compression ; 102 cylinders of concrete 6 inches in diameter by 12 inches; tensile tests of 9 steel reinforcing bars. (3) For the ceramic section: Eighty-seven porcelain

cylinders 1^ inches in diameter and 36 1-inch porcelain cubes for

compressive strength; 19 transverse tests of clay briquettes and 25

of brick. (4) For the lime section: Fifty-four tests of 2-inch lime

cubes and 50 tests of 6 by 12 inch cylinders both in compression.

Inspections of reinforcing steel for the Bennings viaduct were

conducted at various steel mills for the Commissioners of the District

of Columbia by this department.

Statement Showing Number and Value of Testis at the (Pittsbuegh Labokatoey) Btoeau of Standaeds. Fiscax Year 1918-19.

For Government. For public. Total.

Number. Value. Number. Value. Number. Value.

Cement 2,804

61 122

585

§7,924.00

673. 00

936. 00

2, 073. 50

2,80)

61 169

586

87, 924. 00

673. 00

1,091.00

2,083. 50 Miscellaneous Chemical

Total

47

1 S15510

3,572 11,606. 50 48 165 3,620 11,771.50

oln addition to the above, preliminary tests on samples of clay, for which no fee is charged, were made

on 39 samples. GLASS.

(Examination of raw materials for glass and for glass pots; development of Improved methods for making glass pots ; design of plant for manufacture of glass pots on large

ecale ; manufacture of a particular quality of optical glass on large scale for Govern- ment use.) Steady progress has been made in the development of optical-glass

manufacture at the Pittsburgh laboratory. New procedures in molding, such as gathering direct from the pot and softening the glass

in the glory hole were tried out. The results of the investigations on

annealing conducted at the Washington laboratory were applied in

the Pittsburgh plant. The melting schedules have been more and more standardized.

The indices of refraction, the dispei'sion value, the percentage light

transmission, the oxide composition, and the batch mixtures of the

optical glasses made at the Pittsburgh laboratory are given in the

following tables:

Optical Peopeeties of Glasses Made bt the Bueeau of Standards.

Kind. Nd. Ne. Nf. N,. V. T.

1.582 1.578 1..592 O1.600 43.6 99.7

1.624 1.618 1.635 1.645 37.0 98.5

1.648 1.643 1.661 1.673 35.0 99.1 1.518 1.515 1. .523 1.528 59.8 98.8 1.570 1. 567 1.577 1.590 58.2 99.0

1.610 1.607 1.618 1.630 56.0 96.0

1.516 .1.514 1.522 1. 527 61.6 97.8

1.550 1.548 1.560 L 565 52.0 99.5

aN,l, Nd, No, N t, Ng=indices of refraction for T>, C, F, G lines, respectively, of the spectrum. V=i dispersion; T=>transmission.
BEPORT OF DIRECTOR OF BUREAU OF STANDARDS. 273

Composition of Glasses Made by the Bueeati of Standaeds. .

I. OXIDE COMPOSITION

SiO.2 PbO BaO ZnO CaO AI2O3 K2O

from K2CO3

53.9 45.2 39.3

66.7 48.0 39.0

66.

5

58.8

32.3 44.8

48.1

5.0

2.0 4.8

2.50

1.10 2.20

3.7 4.0

10.6 28.5

45.0

7. 8 12.3

1.5 8.4

7.0

2.2.5

Barium crown 2.0

1.00 2.9

13.7 1.0 4.0

K2O

from IvNOs

Na.20 from NajCOs

NaoO

from

barax

AS2O3 SboOs B2O3

from

borax

B2O3

from

biric a3id

Li<;ht flint 5.00 3.00

4.60

1.3 4.0

2.6

2.9

4.3

1.00 3.50

0.4

.4

.2.4

.5

.4.2

Dense flint 0.9 Li^ht crown 10.87

.15 1.431.86

3. .50 Barium crown 4.26 0.33 5.00

2.00 Dense barium crown

7. 10 .70 2.70

1.00 5.90 Barium flint 1.70

II. BATCH COMPOSITION

SiOz PbO BaCOa ZnO Ca

(0H)2 AI2O3 KNO3

Ll'ht flint 49.1 42.2

33.9

.56.2 40.6 32.7

.56.9 51.3

29.0

41.4

45.2

6.26

2.55

4.51

9.50

5.90 9.45

2.28

7.05

4.65

5.81 7.94

Melium flint Dense flint Liglit crown 11.55

29. 05 48.23 8.?8

15.94

1.24 7.05

5.91

1.67 2.11

Barium crown 2.33 Dense barium crown 0.83

Borisilioate Bariimi flint 11.9 1.22

NasCOs SbjOs Boric

acid Borax K2CO3

Li<?ht flint 1.41 5.50

0.33 4.4

2.0

3.84

5.72

5. 86

.20

,.33 0.90 Lieht crown 15.45 7.23 Barium crown .40 7.19

.33

.18

.33

0.47

7.35 3.30 Dense barium crown

10.60

1.22 9.04

3.66

5.93 6.38

Colored Glasses.

A series of red g;! asses covering a wide range of composition have

been made with the use of selenium and cadmium compounds and

the heat treatment necessary for bringing out the color determined.

Similar work has been done also with other colors, it being the intention to develop a complete series accompanied by spectroscopic and

other optical determinations.

Washington Glass Plant.

The new melting furnaces, pot arches, annealing and molding

ovens have been erected, and the plant is ready for operation.

Work has been begun on the making of disks for large lenses. 14228&—19 ^18
III. THE OFFICE.

[OfEce management; finance and accounts; personnel actions and records; editorial work,

printing, publicity; property and stores, including distribution and accounting; mail and

files, including test records; scientific library; dispatch, including all forms of transporta- tion and communication; purchasing; stenography, typewriting, and duplicating; and

information service.]

I. GENERAL.

ORGANIZATION.

During the fiscal year 1918-19 the office division has changed from

a war to a peace basis. The Office is organized in 10 sections, and

includes also all clerks assigned locally for the office work of the

divisions. The sections are designated finance, personnel, publicity,

property and stores, mail and files, library, dispatch, purchases,

copying (detailed), information. Each section has a definite function, and it is the aim that each section shall handle all Bureau

business which properly pertains to such function. This policy is equally true of the scientific sections and the sections of the mechanical plant.

During the year the organization has been making steady progress. A systematic plan of charting functions and procedure has resulted

in greatly facilitating the handling of the Bureau's business. A

simple and novel system of office organization is being perfected, the

main features of which are as follows

Function chart, tabulating all Office functions, grouped into sections of related work.

Process chart for each Office function (about 200 in all), showing actions and

action points, diagrammatically tracing the course of action. Standard practice, describing each step in eacli function clearly and completely enough to instruct a new clerk or an alternate. Time standards showing for each function approximately the number of clerk hours required daily.

Office calendar, a schedule of all periodic functions.

Staff! assignments, a chart of 12 diagrams showing assignment of staff to office functions. Arrearage record, showing clerk hours arrearage for each function. Arrearage adjustment, reassignment of staff to duties and duties to staff upon

basis of (a) peak and valley loads of incoming work, (b) net resulting arrearage

after temporary simplification or deferment during peal\ periods.

Residual arrearage is to be met by (a) permanent reduction of routine or more

automatic methods, (h) transfer of work, or (a) estimates for extra help. Alternate system by which absentee's worli is handled by understudies, and

auring interim needed duties are handled, readjusted, or simplified.

Space.

The growth of the Bureau and the steadily increasing volume of

work being handled call for additional space. In fact, the Director's

offices, including the central administration, conference rooms, library

reference room, and stacks, and the various sections of the Office division will eventually require an administrative building, preferably of

274
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 275

the modern office type. It is hoped tliat phxns will be prepared with

a view to submitting such an estimate within a year or two. The pres- ent offices were designed to be available as laboratories and could be

so used. It would be both economical and efficient to have the administrative building equipped with the special facilities required in the

varied work of the central offices.

Staff. The readjustment of administrative salaries generally and of the

wages of skilled workers emphasized the importance of providing a

suitable scale of pay for the section chiefs in the Office sections and

in the general scale of clerical salaries. A recommendation will be

made to this effect in submitting the estimates. The equity of equal

pay for equal training and experience is becoming recognized and being applied generally, assuming an acceptable standard of quality of

work. The clerical work is essential work as important as any other,

and the salaries should be commensurate, both to develop ability from

the present personnel and to secure new appointees of ability when

required. Given mental alertness, interest, and good physique, the

necessary training can be acquirecl in the Bureau for practically all grades of work. Sue ess has been shown in cases which appeared unpromising. Conscientiousness, interest, and esprit de corps are the

strongest factors in se iiring efficient service, and it is believed that

the success of the Office work during the past j'ear has been largely

due to these qualities in the Office staff.

2. SECTIONS.

FINANCE.

(Records of appropriations and allotments; order and voucher accounts; balances; re- imbursements ; cbecking commercial, construction, and travel expense voucbers ; pay rolls

;

test fees; fiscal statistics.) Funds and Disbursements.

The regular appropriations of the Bureau, including the war

funds, amounted to $1,266,860. In addition, $179,300 was assigned

by the President to the Bureau from the national security and defense fund for special investigations on war problems and to complete laboratories under construction. At the request of several

departments of the Government the Bureau undertook special cooperative researches, for which purpose approximatelj^ $643,000 was

allotted to the Bureau. The Bureau appropriations were also di- rectly reimbursed by about $285,000. The total expenditures during

the year amounted to approximately $2,674,160.

Staff. After the signing of the armistice the accounting staff was reduced

by three, although the numerous reimbursements entailed much extra work in rendering the necessary vouchers and following the cases through to final settlement. The assignment of a clerk as '' voucher

runner" has greatly facilitated the payment of vouchers. Close

watch is kept on the location of vouchers within the Bureau to reduce

delay at all points along the line. The transfer of the audit staff to the north building temporarily i-elieved the congestion in the

quarters of the finance section.
276 KEPORT OF DIEEOTOK OF BUREAU OF STANDARDS.

Office System.

The installation of a special card system and visible index for pay

rolls resulted in a quicker and more accurate method of preparing

the rolls. The numerous Bureau funds, and allotments within the

Bureau (about 250 in all), made it essential to have some quick

method of reference. A visible index is now being used for this

purpose, and this clearly indicates at a glance the titles and amounts

of appropriations, allotments, funds from other sou.rces, etc. Appropriation Statements.

The following statement shows the amount and object of each

appropriation provided for the Bureau for the fiscal year 1919, the

disbursement during the year, the amount of imfilled and unpaid

orders at the close of the year, and the unexpended balance remaining at the close of business June 30, 1919

Appropriation. Amountappropriated.

Disburse- ments. Liability.

Salaries Equipment

Repiirs an4 alterations General expenses Orounls

Hi"h-potential investi'^ation Testin i structural materials

Testin'; michines

In 'esti ;atinn fi-e-resistin': properties In 'estimation public-utility standards

In 'esti';otion r di vay miterials Testin ; mis ellancous materials Radio roseirch Color Stan lardi^ation Investi :ation clay products

Deterrainin'; physical constants Stan lirdi'.in ; mechanical appliances In -esti ratinn'of optical srlass Stan lard miterials In .'estimation of textiles, etc Su^ar technoloccy standards Gau^e standardization Renevval of storage bitteries Military research, 1918-19 In estimation of mine scales and cars, 1918-19 In ^•estimation of public-utility companies, 1918-19. Testinm railroad s:ales, etc NATIONAL SECURITY AND DEFENSE.

Military reseirches Robert's coke "oven Thermite in •estimation Altitude laboratory PoTer plant equipment (industrial laboratory). Completinm laboratories Armiment of fortifications, Commerce transfer.. Aviation, Navy, Commerce transfer Equippinm laboratory, 1919-20 Industrial research, 1919-20

Total.

$432,360,00 75,000,00

6, 000, 00

50, 000, 00

7, 500, 00

15, 000. 00

a 222,733,04 30,000,00

25, 000, 00

6 5,5,394.84

15, 000, 00

30, 000, 00

20, 000, 00

10, 000, 00

20, 000, 00

5, 000. 00 10,000,00

c 84,388,75

4, 000, 00

10,000, 00

i 21,350,00

t 433, 000, 00

20, 000, 00

/ 566,547.68

15,000. 00

g .53,522.52

40, 000. 00

100, 000. 00

80,000.00

4,300, 00

60, 000, 00

31,.500. 00

235, 000. 00

h 131,8.50,00

5, 000. 00 100,000.00

50, 000. 00

3, 074,446.83

$342, 545. 03

54, 322. 44

5, 688. 11 18,969.55 4,672.18

11,429.08 212,166,50

26,314, 13 21,057,38 44,594.04

12,053.25

24, 706. 35 18,763.23 8,143.04

16,329,91

4, .540. 40 5,315.43 70,213.74 3,278,02

0,407,06

15,731.47 367,291.84

2, 575. 09 510,211.49

10,796.17 38,813.98

3.5,220,83

.59, 29,

3, 59,

169,

58,

4,

3,

5,

941.04

753. 46

454. 25

897. 19 3i.S6

327. 32

872.71

177.14

026. 92

195.11

$33, 690, 28

18, 020. 05

305. 58

28, 199. 64

2, 736. 40

3, 502. 26 7,633.81 3,304.88

3,485.48

5,519. 56 2,800,15

4,602,15

1,231.00

1,800.56 3,391.13

433,38

4, 620, 80 12,6^3,68

641,97

3, 129. 28 5,512.69

64, 329. 28

16,3.58.25

45, 574. 00

4, 005. OS

14,024.11

4, 102. 73

36, 712. 06 45,312.99

780. 16

31,459.75

65, 024, 68 72,875,63

821. 86 17,882.22

3S3.13

2,285,829.74 566, 863. 96

a Includes reimbursement of ,5129 000 frcm other departments.

^ Includes reimbursement of $5 3^4.S4 from other departments,

c Includes reimbursement of $64 38S.75 from other deppnments.

i Includes reimbursement of SI 350 from other departnitnts.

e Includes allotment of $283 000 from Vv'ar Department.

/ Includes reimbursement of S216 547.08 from other departments

Q Includes reimliursement of $3 522.52 from other departments.

A Includes reimbursement of $31,850 from other departments.
KEPOET OP' DIRECTOR OF BUREAU OF STANDARDS. 277

The following statement shows the condition of the appropriation

for the two preceding fiscal years at the close of business June 30,

1919:

Appropriation. Amount ap- propriated. Disburse- ments. Liability.

FISCAL YEAR 1917. Salaries Equipment

General expenses

Repairs and alterations Grounds

Hlffh-potential investiration Refrigeration constants Testing structural materials Testinc machines

Investigating fire-resisting properties

Public-utility standards Railway materials Testing miscellaneous materials Radio research Color standardization Clay products

Physical constants Standardizing mechanical appliances Testing raijoad scales, etc Equipping chemical laboratory, 1916-17. Equipping chemical laboratory, 1917-18. Radio laboratory

Total.

FISCAL YEAE 1918. Salaries Equipment

Genei al expenses Repairs and alterations Grounds

High-potential investigation Testing stnictural materials Testing machines

Investigation of fire-resistmg properties. Public-uti ity standards

Investi'-'atiori of railway materials Testing miscellaneous materials , Radio research , Color standardisation

Investi ation of clay products , Physical constants , Standardiding mechanical appliances

Investi?; ation of optical glass Testing raiiroad scales Additional land

Military research, 1917-18 Gauge standardization, 1917-18 Repairs, power plant

National security and defense. Production of optical glass. New bui ding

Metallurgical work

Production of fabrics Industrial laboratory Robert's coke o^en Thermite investigation

Total.

$311,

50, 28,

•5, 6, 15,

15, 100,

30,

25,

40,

15, 20, a 15,

10,

10,

lb;

44,

.35, 35,

90,

720. 00

000. 00

500. 00

000. 00 000.00

000. 00

000. 00

000. 00

000. 00

000. 00

000. 00

000. 00

000. 00

359. 71

000. 00

000. 00

000. 00

000. 00

750. 00

000. 00

000. 00

000. 00

$289, 777. 80

49,613.-52 28,276. 36

4, 731. .39 5,935. 67 14,874.83 14,934.19

99,014.41

29, 716. 27 24,910.75

39, 704. 87

14,856. -^O 19,901.12

14,651.73

9, 740. 45

9, 973. 39 4,471.62

9,482.81

44,,558. 89

31,790. 70 34,697.59

86, 688. 97

S386. 48

223. 64 34.85

4.40

15. 00

259. 08 29.69

20.04

92.34 2.17

100. 00

57.53

34,3. 87 52.58

209. 30

5. 26 3,277.00

916, 329. 71 885,303.85 5,113.23

348,

55, 35,

5,

6, 15, 204,

30,

25, 50,

15, 20,

10,

10, 10,

5, 10,

10,

40,

25,

c 485,

ci 226,

12,

, 900, 00

,000.00 000.00

000.00

000. 00

000. 00

773. 83

000. 00

000. 00

000. 00

000. 00

000. 00

000. 00

000. 00

000, 00

000. 00

000. 00

000. 00

000. 00

000. 00

818. 01

972. 47

000. 00

« 112, 762. 00

250, 000. 00 100,000.00

35, 000. 00

893, 500. 00

5, 000. 00

700. 00

3,051,426. 31

316,613. 53 53,670.45

33,563. 57 4,945.18

5, 801. 66 14,182.62

177, 199. 80

29,140. 89 24,849.62

49, 928, 19

14,498. 73

19, 9.51. 28

9,969.21 9,381.30

9, 994. 53 4,994.31 9,563.18

9, 789. 78 39,591.44

444,415. 32

222, 7 '6. 62

11,566. 87

108, 222. 22 249,070.44

97,606. 07 24,904.23

883, 223. 97 4,633.45

051. 60

2, 884, 670. 09

1,329. 55 599.43 46.00

47. 66 658.47

27,319.21

440. 88 33.19

71.81

212. 27 28.84

632. 88

9.65

135. 50

165.57

35, 800. 69

3,539.40

177. 70

1,473.92

877. 09

2,l--'6. 63

10, 078. 28

9, 796. 03

76. 61 4.00

95, 601. 26

a Includes reimbursement for $15,359.71.

b Includes reimbursement of $54,773.83 from other departments,

c Includes reimbursement of $235,818.01 from other departments.

d Includes reimbursement of $1,972.47 from other departments,

c Includes reimbursement of $37,762 from other departments. Summary of Tests. The Bui-eau's work includes, among other things, a large amount

of testing standards, measuring instruments, and rnaterials. Incident

thereto much testing involves primarily the investigation of the
278 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

scientific princiiDles underlying the tasts. the studying of existing

methods, and the develo]3ment of new standard tests of determinate

accuracy. For each test a reasonable fee is charged, except when

made for the National or State Governments.

During the fiscal year 1918-19 the Bureau made 124,668 tests and

inspected 5,076,961 incandescent lamps at various factories for other

departments of the Government. Of the total tests, 110,468 were

for the Government and 14,200 for the public. The testing was dis- tributed as follows, according to the nature of the tests: Length

measui'es. 9,951; mass. 2,022; capacity, 186; optical, 2,161; h3rdrometry, 3.485; time, 2,278; temperature', 19,164; electrical, .3.570; photometr,y, 3,510; chemical, 22,664 (physical and mechanical tests);

engineering material, 1,593; structural material, 44,738; paper and

textile, 8,162 ; metallurgical, 539 ; aeronautical instruments, 645. The

estimated fees amount to $677,873.64, of which $21,169.16 was col- lected on account of tests for the public. The fees noted for Government tests were included merely for comparison purposes, as no fees are charged for tests performed for the National or State Governments. NUMBEU AND VALTTi OF TESTS COMPLETED, FISCAL YeAE ENDING .TUNE 30, 1919. AT WASHINGTON.

For Government. For public. Total.

Nature of test. Number. Value. Number. Value. Number. Value.

9,482 814,477.45 469 SS98. 10 9,951 $15,075.55

1,060 26, 785. 10 962 491.30 2,022 27, 276. 40

136 1, 203. 21 50 112. 25 186 1,315. 46 1,863 4,171.50 298 1,372.46 2,161 5,543.96

1,360 1,047.35 2, 125 1,080. 75 3,485 2, 128. 10 Time 2,194 867.25 84 309.50 2,278 1,176.75 Temperature 15,892 3,379.81 3,272 3,568.95 19, 164 6, 948. 76 1,878 7, 738. 25 1,692 5, 499. 75 3,570 13, 238. 00

3,421 12,989.00 89 307. 75 3,510 13,296.75

19,264 198,461.01 3,400 6,549.35 22,664 205,010.36 Physical and mechanical

Ensineerinp material 1,538 6,492.00 55 234. 00 1,593 6,726.00 Structural material 43, 166 338, 496. 05 1,572 507.00 44, 738 339,003.05

Pittsburtrh laboratory 3,572 11,606.50 48 165. 00 3,620 11,771.50 Paper and textile 8,096 30, 253. 00 66 262.25 8,162 30,515.25 522 1,616.00 17 196.00 539 1,812.00 Aeronautical instruments 596 8, 727. 50 49 79.75 645 8,807.25

Total 114,040 668,310.98 14,248 21,334. 16 128, 288 689,645.14 AT PITTSBURGH.

Cement 2,804 S7,924.00 2,804 $7,924.00 Clay products 61 673.00 61 673.00 Miscellaneous • 122 936.00 47 S155.00 169 1,091.00 Chemical 585 2,073.50 1 10.00 586 2,083.50

oin addition the Bureau inspected 5,076,961 incandescent lamps at various factories for other depart- ments of the Government, the fees for which would amount to $12,692.40. b Of these tests 8,091, amounting to $121,365. were chemical te.sts made on structural material.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 279

PERSONNEL.

(Organization charts of divisions ; staff status, individual records of all employees, in- cluding military employees ; appointments and personnel changes ; directories ; systems of examinations ; records of leave, tardiness, delinquency, and efficiency ; passes and cre- dential cards ; injury and first-aid records and reports ; and records of employees who

liave entered the military service.) The work in the personnel section covers a wide range of functions,

all pertinent to personnel work, but involving a large volume of

clerical detail. All of such routine has been carefully standardized,

and a system of process charts was adopted. Each function shows

the steps required and the action points. These serve as a guide in

standardizing procedure and to instruct new clerks. Present Personnel.

During the year the Bureau staff comprised 341 statutory employees and about 809 engaged in research and investigations

specially authorized by Congress. The statutory positions included

201 scientific positions, 52 office assistants, 55 engaged in the operation of the plant, and 33 in the construction. In addition to the

above there were 300 employees detailed from other Government departments and organizations during the year for work in the Bureau.

The Bureau more than doubled its force cluring the war.

Effect of War and Armistice on Personnel.

The personnel at present consists of over 1,000 regular appointed

employees, as compared with approximately 500 prior to the war. The highest number of employees at any one time during the year was approximately 1,450, of which 300 included detailed employees

from the Army, Navy, or other Government establishments. On

June 30, 1919, there were 1,140 employees, of which 60 were detailed

employees. The above figures show that the force has been reduced

by approximately 310 employees since the armistice was signed.

These included 240 detailed employees and 70 regular employees.

Personnel Changes.

There were 4,300 personnel changes during the year. These in- cluded 1,505 separations from the Bureau, of which 378 were resignations, 774 promotions, and 1,909 appointments. The high labor

turnover will give some idea as to the large amount of work required

in keeping positions filled. How serious is the unusually heavy drain,

due to the demand for trained employees, is shown by the fact that

1,505 out of a total force of 1,909 regular appointed employees, or over 78 per cent, left the service during the past year. A detailed

statement of the personnel changes is given in the following table:

Personal Changes, 1918-19.

NatOTe of position. Appoint- Separa- ments. tions.

Competitive

Excepted , Unclassified Total permanent Temporary

554

1427 595

1,314

5 378

1,127

372
280 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Summary.

Appointments 1,909

Separations 1, o05 Promotions 774 Reductions 23

Otlier clianges 89

Total personnel changes 4, 30O

Personnel Records.

The personnel charts were revised during the year and placed in

book form, with a new type of visible index. This provides a neat

graphic record of the staff status instantly accessible and visible

and facilitates the entries of personnel changes. A list of all employees by grades and seniority on all funds was compiled during the

year. This record is on-a visible index file and shows at a glance all employees in each grade by seniority. Such data are so often called

for that considerable time will be saved in prejDaring lists. An

efficiency record is kept of all junior employees.

Annual and Sick Leave.

The following table shows the total and average amount of annual

and sick leave taken by the employees of the Bureau during the

calendar year 1918

Leave. Days. Average.

6,362

2,296

15.

Sick 5.4

Total, 1918 8,658 20.4 24.8

Eligibles.

A satisfactory arrangement was effected to secure prompt certifica- tion of eligibles in important cases. This saves at least 10 days in

making appointments. Owing to the variety of experts required and

the heavy demand for labor, the civil-service registers proved inadequate. It was necessary to seek temporary assistants in nearly 75

per cent of the cases, nearly all of whom subsequently qualified by

examination and were given permanent appointments.

Employees in Military Service.

Approximately 90 employees left the Bureau to enter the organized

military service during the war, 2 of these having been killed in

action, 1 dying of disease, and 1 dying by accident. Employees who

entered the military service and who have applied for reinstatement

are being restored to the Bureau rolls in their old positions. In no

case has the salary offered been less than that which the employee was receiving when he left the service. Many of the Bureau's experts were necessarily retained for scientific research in connection with

military problems.

Additional Work.

The method prescribed by law for recommending employees for

the bonus entails much extra work on the personnel section. Indi-
EEPOKT OF DIRECTOB OF BUREAU OF STANDARDS. 281

vidual recommendation is required in each case where the employee

has entered the service since June 30, 1918, or where employees have

been promoted in excess of $200 since that date. It is also necessary

to keep records of the bonus for immediate reference, it being neces- sary to verify each change in an employee's status. Detailed data

is also furnished to the Commission on Eeclassification of Salaries

as to each personnel change, and duties of old and new positions.

PUBLICATIONS.

(Editorial worlj, routing of manuscripts and proof documents ; archives ; tiandling re- quests for publications, preparing franks ; publication stock distribution ; abstracts of

publications.) Publications Issued During Year.

The publication work of the Bureau was reduced to a minimum

during the war, so that all possible service might be rendered to the

militarjf departments directly in experimental and investigational

work. However, during the fiscal year the Bureau issued 53 publications, 36 of which were new and 15 revised editions. Forty publications were reprinted without revision. The new publications comprised 12 scientific papers, 15 technologic jDapers, 6 circulars, and

3 miscellaneous publications, as listed below

:

Scientific Papers.

Wave Lengths in the Red and Infra-red Spectra of Iron, Cobalt, and Nickel

Arcs. Spectroradiometric Investigation of the Transmission of Various Substances.

Electrical Oscillations in Antennas and Inductance Coils. Measurements on the Index of Refraction of Air for Wave Lengths from

2218-A to 9000-A. Variance of Measuring Instruments and Its Relation to Accuracy and Sensitivity. Measurements of Wave Lengths in the Spectrum of Neon. The Decrease in Ultra-Violet and Total Radiation with Usage of QuartzMercury Vapor Lamps.

A Relation Connecting the Derivatives of Phj'sical Quantities.

Preliminary Determination of the Thermal Expansion of Molybdenum.

Optical Conditions Accompanying the Striae Which Appear as Imperfections

in Optical Glass. A Simplification of the Inverse-Rate Method for Thermal Analysis.

Combustible-Gas Detectors. Technologic Papers.

Determination of Permeability of Balloon Fabrics. A Portable Cubic-Foot Standard for Gas. New Baume Scale for Sugar Solutions.

Silica Refractories—Factors Affecting their Quality and Methods of Testing

the Raw Materials and Finished Ware.

Toluol Recovery.

A Critical Study of the Ledebur Method for Determining Oxygen in Iron and

Steel. The Ultra-violet and Visible Transmission of Eye-protective Glasses. Tests of Hollow Building Tiles. Strength and Other Properties of Wire Rope.

Tests of Eighteen Concrete Columns Reinforced with Cast Iron. Physical and Chemical Tests of the Commercial Marbles of the United States. Constitution of Silica Brick and Changes Involved Through Repeated Burnings at High Temperatures.

Viscosity of Gasoline. A Study of the Goutal Method for Determining Carbon Monoxide and Dioxide

in Steel. The Effect of Solar Radiation upon Balloons.
282 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Circulars.

Publications of the Bureau of Standards. Aluminum and Its Light Alloys.

The Table of Unit Displacement of Commodities.

Solders for Aluminum.

Electrical Characteristics and Testing of Dry Cells. Recommended Specification for Linseed Oil—Raw, Refined, and Boiled. Miscellaneous.

Proceedings of the Second Annual Textile Conference Held at the Bureau of Standards (1917).

Metric Manual for Soldiers. Annual Report of the Director for Fiscal Year Ended June 30, 1918. Distribution.

As provided by law documents are mainly distributed by the

Superintendent of Documents. A proper selection of suitable publications to be sent in response to many of the requests for technical

data can be made only in close contact with the technical sections

of the Bureau. The franks, therefore, are prepared at the Bureau in

the publication section.

List of Publications.

During the year the Bureau completed and published a full list of publications issued by the Bureau since its establishment. The

catalogue is descriptive and gives for each title a technical abstract

of the publication, and a comprehensiA^e index. The Bureau will

issue a quarterly supplement to include new publications published

during the quarter. This list of publications has already proved of

great value in guiding the economical and efficient distribution of

Bureau publications. The abstract gives so clearly the nature of the

subject matter that an expert can promptly decide whether the publication meets his need. The abstracts form an excellent summary'

of the entire published work.

PROPERTY AND STORES.

(Property inspection; quantity and quality checking; accession, recording; accountability, charge and release ; condemnation and disposal ; stores, stock distribution, and re- newals.) Equipment.

During the year 50,000 pieces of equipment were received, serially

numbered, and taken up on the inventory records. New engraving

and stenciling machines were procured to facilitate the placing of

Bureau accession numbers on all pieces of equipment.

Perpetual Inventory Records.

The improved system of perpetual inventory records is now fully

established. All necessary record entries are made at one wi-iting in

place of the three separate writings formerly required. This greatly

facilitates prompt local and central handling of inventory and property transfers.

Technical Supplies.

During the year technical supplies valued at $65,000 were issued

to the various technical divisions and offices. The systematic arrangement and segregation of technical supplies in the storeroom enable

the attendants to give quick service, each class of stock having a
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 283

specific and indexed location. The new card system shows at a glance

all stock on hand, amounts issued, and organization unit dra wing the same. This permits the complete accounting for all supplies issued

and charging of same to proper units. The system works well, and

the main storeroom is now supported wholly by reimbursement from

allotments to the various divisions.

Additional Space Needed.

Additional space is seriously needed to permit the stock to be kept on one floor, systematically arranged on shelves according to classeis of material. The main stock supply is now in the attic. Suitable'

quarters would reduce by two-thirds the labor in handling supplies,

and the attendants could more promptly and efficiently serve the

technical needs.

MAIL.

(Handling of incoming and outgoing correspondence of all kinds; the accession, dis- tribution, and filing of such papers.) Filing System.

Marked progress was made during the year in perfecting the central filing system. An accurate check is now available for the loca- tion of each letter. Two sets of reference slips are filed, one according to organization unit of reference and one according to date, the

file for incoming and outgoing letters being kept separate. This has

saved appreciably in time and labor, and promoted the efficient handling of correspondence.

New Equipment.

A new motor-driven letter opener saves the time of one employee

previoush' needed for the work. A new device desigiied and constructed at the Bureau is used to pliotograph all important incoming

mail,f using for the purpose a motion-picture film. The photographic

reference record of incoming letters, by means of a suitable projector,

is used to throAv the image of the letter on the screen. The original

letters, as soon as photographed, are at once available for distribution

to the divisions of the Bureau. The saving of one to two hours' delay enables the mail section to deliver the morning mail to the laboratories by 10 o' clock. Subject Filing.

The Bureau correspondence is filed by subject. In each unit subject, however, a series of monthly folders facilitates the transfer of

back correspondence. This simple device greatly simplifies the clear- ing of the current files and transfer to the permanent cases. Filing Equipment.

The new equipment obtained for properly handling the large

volume of correspondence has. included a sorting cabinet, small-letter sorters, filing units, transfer cases, and visible guides. Floor

space urgently needed for systematic storage of back correspondence

and records is now available, since the photographic shop is trans- ferred to the industrial laboratory.

Personnel.

The mailroom staff has shown cooperation to a marked degree

in excelling previous performance in the proper handling of the
284 KEPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Bureau's correspondence. The arrearage of work occasioned by the

loss of experienced clerks due to the war has been gradually over- come, and with new equipment already ordered the work can speedily

be brought up to date. LIBRARY.

(Maintenance of scientific and technical library ; bibliography ; selection of new refer- ence books ; preparing book lists for purchases ; accessioning new books ; loans and ac- countability records; assistance to technical staff; aud binding of books and periodicals.) Accessioned Volumes.

At the close of the fiscal year the technical library of the Bureau

had 17,742 accessioned volumes. Except for a few law books, these are all of scientific and technical character, chiefly in the subjects of

physics, chemistry, engineering, and special technology. During the

fiscal year 346 new volumes were accessioned.

Technical Journals.

The Bureau receives currently 442 scientific and technical periodicals. During the year steps were taken toward completing some of

the more important sets which are in great demand at the Bureau.

About one-half of the periodicals are received by exchange with the

Bureau's publications. The following is an interesting analysis of

the technical journals currently received, including a statement of

the total number of separate parts

Subscription. Exchange. Total

journals. Totalparts.

8449

1709

3

115

55

21

199

10438

fi9 32

3,889

1,645

584 1,640

284 German

29

Total 222 220 442 8,04

Circulation.

Apart from the consultation of books in the library itself and the

desk copies of important texts permanently assigned to the laboratories, there was a rnonthly average circulation of 500 books and

journals. Through the cooperative arrangement with the various

libraries in Washington, more than 500 loans were made to the

Bureau. In return, the Bureau makes loans to experts in other

institutions and tenders the Bureau's facilities and library for consultation and reference.

Additional Space.

In common with every other section of the office, additional space

is urgently needed. A new periodical rack is required and additional

stacks. The Bureau's library is increasing at a rate to demand

approximately 50 additional shelves per year. Furthermore, the

question of consolidating the overflow library now located in the

attic and transferring it to the main library should receive early

attention. This can be done when additional space and stacks are

available.
REPORT OP DIRECTOR OF BUREAU OF STANDARDS. 285

DISPATCH.

(Transportation and communication of all kinds, comprising telephone and telegraph

service, express, freight, and mail shipments, drayage, motor-cycle, and other messenger

service in and out of the Bureau.) Shipping.

The consignments handled by the dispatch section of the Bureau

during the past year far exceeded the business of any previous year. The system for recording the same has been in successful and satis- factory operation during the year. In view of the variety and the

delicate or dangerous nature of the many instruments and materials

shipped, the results are gratifying. However, with the consolidation

of the Pittsburgh laboratory and the desirability of improving the

promptness of the service, especially during peak periods, at least one experienced packer and two laborers should be added to the

shipping-room staff. Quarters.

The present temporary quarters suffice for the present. Permanent provision should be made—probably in another building—for a

well-designed shipping room, with loading platform and modern

facilities for good traffic management.

PURCHASE.

(Trade catalogues and dealers' lists ; requisition inspection ; preparation of bids, re- quests, advertising, and orders; order follow up; purchase and transportation checking.)

Requisitions and Orders.

During the year 8,800 requisitions were placed for supplies and

equipment necessitating special orders. A shortening of the routine

now permits all orders to be mailed the same day as written, saving a

full clay's time in each case. The purchase section has placed travel- authorization requests on the same basis as or^lers, and is handling

them efficienth\

Records.

An excellent sj'stem of records is in successful operation, and

needed information is obtainable promptly. The follow up established during the year proved effective in expediting the checking of

material received and jDayment of vouchers. A special clerk designated as " voucher runner " sees to it that all accounts are handled

promptlj', or adequate reason is given.

Bids.

The last approi^riation act requiring that bids be solicited of all Government departments before purchasing from outside contractors greatly increased the work of securing material and involves some

delay in securing needed equipment and supplies.

Space and Assistance.

The concentration of purchase woi'k in the purchase section has

entailed much extra work for which additional assistance should be

provided to carry it efficientlj'. Larger quarters will be needed or the

efficiency of this service will be impaired.

Catalogue Library.

The Purchase Section maintains an excellent catalogue library ar- ranged alphabetically, by firms, and indexed by classes of articles,
286 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

including- especially scientific and technical equipment and supplies.

In addition a record is kept of the location of all catalogues assigned or loaned to the staff. COPYING.

(Editing rough drafts of letters, reports, and manuscripts ; stenography ; typewriting

and mimeography.)

The purpose of the copying section can not be efficiently served

until an adequate force of typists is aA-ailable to take over all the

principal dictation and general typewriting of the office section. If

this proves feasible, the consolidation should be extended to include

most of the work of the scientific and technical sections.

The members of the copying section assisted in preparing the details of office practice and procedure charts, including organization

charts of routine, staff assignment, and functions in connection with

the general office-organization plan. The plan is novel and comprehensive. The details are described in another part of this report.

Other work of the section included the loaning of temporary assist- ance in case of illness or absence on leave, the handling of peak loads

of work in various parts of the Bureau, ininieograph work, and the

taking of miscellaneous dictation.

The plan for the development of a copying section includes the

ultimate provision for a sufficiently large room where all clerks en- gaged in copying work could work systematically together, so that

the assignment and systematic record of Avork could be facilitated. INFORMATION.

(Reference of technical correspondence ; maintenance of a progress-of-work chart and

fol'ow-up system covering all tests, sub.iects of inquiry, investigations, and researches in progress foi- the military services and to some extent for civilian agencies ; requesting,

receiving, distributing, and filing of scientific and technical information of a military

bearing.) Progress-of-Work Records.

Tlie initiation and progress of tests, investigations, and researches

is charted for military and' related work. This now includes the more important nonmilitary work. This forms an available and

full list of the more important technical activities of the Bureau.

During the year 4,209 separate military entries wei-e carried on the

progress-of-work chart, averaging 351 per month, and, in addition,

220 important industrial investigations were charted. The entries

include dates of incoming letter, receipt at the Bureau, receipt of

the materials or specimens to be tested, and of preparation of final report and its mailing, and also the subjects of incoming and out- going correspondence concerning the case. A systematic follow up

and record thereof is provided.

The novel form of chart and notation used lias attracted interest

outside and is being published by a firm publishing forms and digests of data for technical work.

Distribution of Technical Information.

The Bureau receives many technical and scientific data, to some

extent confidential in character. The sources include the Research

Information Service of the National Research Council, tlie Air

Service Information Group, the reference library of the Ordnance
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 287

DepEirtment of the Army, the Bureau of Construction and Repair

of the Navy Department, and the National Advisory Committee for

Aeronautics. Such data are referred to the proper technical di- vision to be utilized as promptly and fully as possible.

The information section also obtains upon request of any authorized member of the staff documents of this character available at any of the usual sources of such information. Six hundred and

twenty-one separate documents of this character have been secured on such requests during the past nine months.

Technical News Bulletin.

The Bureau has dispatched at frequent intervals since December,

1917, to the military and naval technical and exer-utive authorities

and other cooperating services, a confidential bulletin of brief cur- rent news of technical and scientific progress in the Bureau's laboratories,. The diffusion of up-to-date data made it possible for officers of other services concerned to arrange for needed cooperative

work and for early application of the results when exigent work

required.

Recently the confidential nature of the bulletin has been largely

eliminated, and it is now issued as the Technical News Bulletin ot

the Bui-eau of Standards, a few confidential matters of military importance being reserved for a confidential supplement sent only to a

restricted mailing list. During the past fiscal year the confidential or news bulletin has included 135 single-spaced mimeogi'aphed pages,

under a total of 426 separate subject headings. The many inquiries

for information about work in progress based upon this bulletin shows

that it has performed useful service in making technical information

available for early use. Miscellaneous Information Service.

The information section handles many inquiries by telephone and

otherwise for information regarding the Bureau's work and puts the

inquirer in touch with the proper staff expert, a matter of importance

now that the organization is so large and comprises so many and

varied activities. Compilations of information required for various

purposes are also undertaken—as, for example, at the request of the

War Department a history of the Bureau's technical participation in

the work of aircraft production—and for general use and information an analysis of the memberships of experts of the Bureau staff in committees of the various technical and scientific societies with which the

Bureau cooperates.
IV. ENGINEERING AND CONSTRUCTION.

I. POWER PLANT, BUILDINGS AND GROUNDS, AND

TRANSPORTATION.

[Power-plant operation, automobile and truck service, electrical and plumbing installation and

repair, care of buildings and grounds, engineering supplies storeroom.] Operation and Maintenance of Mechanical Plant.

The operation and maintenance of the power plant is a very important part of the work of the engineering division, in that the

entire Bureau is 'dependent thereon for the various laboratory facilities. The power plant comprises the heating, generating, and

refrigeration equipment, the compressed air, vacuum, and high-pres- sure water services, and the storage-battery equipment, both sta- tionary and portable. During the past year a number of additions were made to the several types of equipment of the plant in those

departments which were critically in need of additional facilities. Two 200-horsepower boilei's were put in operation during the past

winter and made possible adequate heating of the Bureau. At pres- ent the intallation of two 350-horsepower boilers in the basement

of the kiln building for heating the industrial and kiln buildings

is nearing completion. Additions to the electrical equipment during the year include a 300-kilowatt synchronous converter and 200

kilovolt-amperes in transformers. The converter, while not exactly

satisfactory from an operating standpoint, is, nevertheless, a great

help in insuring uninterrupted direct-current service. The trans- formers Avere added in order to accommodate several large electric furnaces installed for the metallurgical and heat and thermometry

divisions.

The stationary storage batteries were renewed during the year

and put in excellent condition, a special appropriation having been

provided for the purpose. A nnniber of new portable storage batteries were also added to the plant equipment. The rapid expansion of the Bureau in all its branches, due to its war-time activities,

has placed a severe strain on the power plant, and, while the additions above mentioned have provided means for temporarily

supplying the various laboratory facilities, the present arrangement

of the power-plant equipment is far from satisfactory both from

an operating standpoint and on account of the sizes of the units

and variety of equipment, and must, therefore, be considered as only of a temporary nature. For instance, the entire floor space

of the present engine room has been used for machinery and switchboards, and the synchronous converter necessarily placed in the

northwest building, some distance away; the boilers in the kiln

building will require separate operating crews, both of these cases being an indication of how the operation of the plant has become

decentralized. It was with difficulty that the operation of the

plant was managed during the past winter, and it was only made

possible with several labor-saving devices which were put into ef- fect in the method of coal and ash handling. The construction of

a separate heating and generating plant, including all the mechanical equipment adequate for the present and future requirements

of the Bui-eau, shonld be undertaken at once not only as essential

288
BEPOET OF DIEECTOK OF BUEEAU OF STANDAEDS. 289

To better eiRciency, but also as a necessity against serious interruptions of service, which are, indeed, quite probable with the present

plant. The plant has expanded to a point where further temporary

expansion is almost impossible, and its capacity is frequently taxed

iJmost to the limit. Transportation.

The operation and maintenance of the transportation equipment

of the Bureau is cared for by this section of the engineering division.

The equipment consists of 2 touring cars, 1 ambulance, 1 mail

truck, and freight-handling trucks of the following capacities : One

2^-ton, two f-ton, two 500-pound. Owing to the very large increase

in the work of the Bureau, due to its war activities, the importance

of maintaining adequate truck service to handle the freight, express,

etc., with dispatch is readily apparent. The maximum service possible was obtained from the various machines, and consequently hard

usage has rendered some of the trucks unfit for much more useful

service. Steps are being taken to obtain additional trucks of larger

capacity, and when put into operation they will greatly relieve the

present conditions. Additional space is urgently needed for the

garage besides the temporary building constructed during the year

to house four machines not used for freight handling. Methods of

better adapting the present equipment by changes in construction,

etc., are being considered and Avill probably be carried out during

the coming year. Construction and Repair.

Electrical.—The installation of all electrical wiring, switchboards,

and equipment for laboratory purposes and for maintenance of the

power plant is performed by this section. Owing to the character

of the research work of the Bureau the electrical work is in man}'

cases unusuall}^ complicated, requiring very skilled mechanics. Besides the installation of the equipment, this section also repairs and

extends this equipment as reqiiired. During the past year the in- stallation of equipment in the northwest and radio buildings was

Ijractically completed. There were included in these installations

several electric furnaces of large capacity, wiring of machine tools,

battery installations, and many extensive additions made to the

electrical work throitghout the entire Bureau.

Plumbing

.

—The installation of all pipe work required for v arious

laboratory facilities, including steam, gas, air, vacuum, water, and

refrigeration, is done by the plumbing section. Here, again, owing

to the nature of the equipment, which is installed for various lab- oratory purposes, Avell-trained mechanics are necessary for the pipe

work to be done. The work during the past year, besides including

completion of the equipment piping in the northwest and radio

buildings, also covered a very large number of extensions of piping

throughout the remainder of the Bureau and a very large amount of

repair and maintenance work of the plant equipment. In both the

electrical and plumbing' sections additional help is urgently needed,

and working space Avith adequate tools and facilities is a pressingnecessity. It is possible that, in the verv near future, sufficient room

for a workshop for the plumbing and electrical sections Avill be

obtainable, and such an addition should greatly inci-ease the efii- 342289—19 19
290 BEPORT OF DIRECTOR OF BUREAU OF STANDARDS.

ciency of these sections and improve the character of the woris

];)erformed.

Minor Construction.—Under this section are inchided various

small jobs of construction, such as the building of temporary structures, construction and repair of concrete roads, and repairs and

alterations to existing buildings. The personnel of this section is at present entirely inadequate owing- to the large number of small jo])s

always on hand. During the past year a temporary building was

constructed for housing four automobiles, concrete roads were re- paired, and about 200 feet of new roadway built of cinder concrete. I'aths of cinder concrete blocks aggregating 600 feet in length were

also constructed. Numerous extensions were made to the drainage

system of the Bureau grounds, and the construction of retaining

walls was begun. A number of repairs and alteratioi^s were also made to buildings, including pai'titions, skjdights, painting, etc. Buildings and Grounds.

Janitors and Laborers.—The work of this section is of more oi less routine nature and comprises the cleaning of the maiiy offices and

laboratories of the Bureau and the maintaining of sanitary conditions throughout. Owing to the shifting of the laboratories, due to expansio)!, there was a considerable amount of moving of equipment,

and in all cases where such moving was handled through this sec- tion diiring the past year the work was done most economically.

During the past year the dynamometer and industrial buildings were

practicidly completed, and the northwest and radio buildings, completed during the previous year, were full}' occupied hy laboratories.

I'liere should be a material increase in the personnel of the janitors

and laborers to care efficiently for the buildings now completed.

Guards.—-During the period of the war all of the Bureau buildings were kept under guard, and men were stationed at the entrance doors

of the buildings for this purpose, as well as at the entrance to the

Bureau grounds. Rigid inspection of all visitors was exercised, and

only such persons as could show satisfactory reasons were permitted

to enter the Bureau. Early in the year 1919 the guards were re- moved from the entrance doors of the buildings, but the inspection

and direction of visitors is continued at the entrance of the Bureau

grounds.

Offi.cer of the Day.—This office was provided for the purpose of

having at the Bureau at all hours some one authorized to represent

the Director in all circvnnstances requiring the decision of a responsible officer, when the Director was not at the Bureau. The office was

tilled by members of the Bureau staff, each of whom was on duty

for 24 hours, during which time he did not leave the Bureau. In

order that this office should not Work a hardship on any one person, no one was required to serve as officer of the day more than one day

per month. The numerous occasions upon which this office proved

to be of special advantage are conclusive evidence that the position

should be permanently' authorized and adequate compensation given

tlie incumbent, inasmuch as the members of the Bureau staff haA'e so far served as officer of the day voluntarily and without extra compensation.

Watchmev,.—The duties of the watchmen are to make inspections

of the buildings to prevent fire, theft, damage hy weather, etc.. to the
RBPOET OF DIEECJTOr. OY BUllEAL" OF STA^TDAEDS. 291

Bureau property. The additional buildings recently completed have

adcled considerably to the extent of the work required by the watchmen, and, while a small addition has been made to the number of

watchmen employed, the personnel of this section is still inadequate

and should be materially increased for eiiicient inspection of all the

laboratories.

Grounds.—The care and improvement of the grounds of the

Bureau is included in the work of this section. Owing to the ex- tensive building operations during the past year, certain portions of

the Bureau grounds could not be taken care of as well as they should

have been. It was also found quite difficult during the past year to obtain labor at such times as it could be used to the best advantage in

maintaining the proper care of the grounds.

2. PHOTOGRAPHIC LABORATORY.

[Investigation of photographic apparatus; testing of photographic materials and apparatus;

standardization of testing apparatus and conditions; general photography.]

Sensitometer,

A sensitometer has been designed and constructed for testing the

light-sensitive characteristics of plates and films. This apparatus

consists of three parts: (1) The sensitometer for making accurately

known exposures, (2) the thermostated developing bath, and (3) the

photometer for measuring the test specimens. A circular describing

this apparatus and method of testing was prepared and distributed

to those interested in this work.

More than 100 tests of stained and bathed plates Avere made with

this apparatus for the optical section. This work formed a part of

a military problem in connection with the taking of photographs

from airplanes, and will be foimcl to be treated more fully under

"Aerial Photography " in the report of the optical division.

Developer Testing.

Samples of methol substitutes and other developers were tested for

several Government departments.

Photographing the Mail.

An experimental camera for photographing the mail of the Bureau has been constructed and is found to save considerable time in

briefing and recording the incoming mail. This mail formerly was

held in the file room until the records and brief were made, and was

then delivered to the various sections of the Bureau. By the photographic method the mail is photographed on motion-picture film as soon as received and immediately delivered to the laboratories. The

photographing requires from 10 to 20 minutes for the entire mail.

The film negatives are projected to original size by means of a small

projection lantern and the brief and file cards made. The cost is very moderate ; 16 letters are copied on each foot of film. General Photography.

During the past fiscal year more than 2,200 miscellajieous photographic requisitions were completed. These requisitions called for

photographic work of all descriptions. Much of this was in con- nection with the Bureau's military problems. In addition to this,

the entire personnel of this Bureau (approximately 1,500) were

photographed for pass and identification purposes.
V. GENERAL RECOMMENDATIONS.

Salaries.

So much has been said in former reports, in the submission of esti- mates and the public press as to the inadequacy of salaries of scientific and technical experts in the Government service that it seems almost

unnecessar}' to call attention at this time to a condition so well known.

The disparity existing between the salaries of these experts in the

Government service and elsewhere is so great that the scientific work

of the GoAernnient is rapidly being affected accordingly. It is true that the conditions existing in connection with the war have necessitated many changes in the scientific personnel of the Bureau. Nevertheless the number of changes during the past year amounts practically to 100 per cent. No work can be efficient upon that basis. Such

changes are disastrous to scientific or technical work.

In submitting the estimates for the Bui-eau of Standards for the

coming year it has been assumed that the Joint Committee on Reclassification of Salaries will thoroughly investigate this question and

make recommendations accordingly. All positions, whether old or new, submitted in the estimates for 1920-21 are with the expectation

that the}' will be adjusted by Congress to a new and adequate scale. Power Plant.

The power plant of the Bureau of Standards is entirely inadequate.

It now consists of the original plant constructed for two buildings

and two temporary installations. These installations should be

brought together imder one roof in the form of a small but model

po^^ er j)lant capable of heating the various buildings now existing,

with provisions for its extension in the future. It should also provide the various electrical currents for power and experimental purposes, as well as other utilities required at the Bureau. The need

lor this poAvei plant has existed for tlie past three or four years, but

it Avas thought unAvise to begin neT\- c(mstruction during the war. A

thorough report has been made on the situation by one of the most

competent firms of consulting engineers in the country. It is esti- mated that such a power plant will cost in the neighborhood of $500,-

000. Xn estimate for preparing the plans and beginning the construction of the building for such a power plant will be submitted.

Remodeling of Building for Mechanical Plant.

The building in which are housed the instrument shops and much

other construction work was the first erected at the Bureau, and has

become entirely inadequate for the purpose designed. A remodeling

of the roof of this building will make available an entire story. Provisions for this alteration have been requested in the former esti- mates and will be resubmitted for the years 1920-21.

Additional- Land.

I would again call attention to the urgent necessity for acquiring

the plot of ground between the Bureau's site and Van Ness Street on

the north and that betAveen the Bureau's grounds and Tilden Street on

292
REPORT or DIRECTOR OF BUREAU OF STANDARDS. 293

the south. Estimates have been submitted previously, and an appropriation was made two years ago. This, however, proved to be inadequate. A careful study has been made of the situation and an esti- mate will be resubmitted. It is to be tegretted that, through misunderstandings and the great difficulty which always attends the purchase of real estate, these strips have not been secured heretofore, as it was evidently the intention of Congress when the appropriation was made that they should be acquired.

Care of Buildings and Grounds.

It has been practically impossible, as well as inadvisable, to expend

much money or labor upon the improvement of the grounds during

the war pei'iod. Nevertheless, the time has come when a sufficient sum

should be provided for the development of a simple but appropriate

plan for the grounds of the Bureau of Standards and the putting of

the same into effect. The appropriations for this purpose in the past

haA^e been such as to cover only a small amount of the most urgent

improvements in the way of roads, walks, pipes, wires, etc. An esti- mate will be submitted for the purpose. It is realized that this car

not be accomplished in a single year, but the most necessary improve

ments should be provided for at once. Test-Car Depot,

Estimates will be submitted for a small building in which to house

and care for the Bureau's test cars and master track scale. This

building should be situated at some central place. This important

service can be made more efficient by providing a small depot centrally

located. Every effort has been made to handle this from Washington,

but experience has shown that a small substation centrally located is necessary.

Respectfully,

S. W. StrattoNj Director.

To Hon. William: C. Redfield,

Secretary of Commerce.

o