ANNUAL REPORT

DIRECTOR

BUREAU OF STANDARDS

SECRETARY OF COMMERCE

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: ^^^TM FOR THE ' "

FISCAL YEAR ENDED JUNE 30, 1920

(Miscellaneous Publications—No. 44)

WASHINGTON

GOVERNMENT PRINTING OFFICE

ANNUAL REPORT

OF THE

DIRECTOR

BUREAU OF STANDARDS

TO THE

SECRETARY OF COMMERCE

FOR THE

FISCAL YEAR ENDED JUNE 30, 1920

(Miscellaneous Publications—No. 44)

WASHINGTON

GOVERNMENT PRINTING OFFICE

1920
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 specificially the form 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 publi- cation is no longer desired.
CONTENTS.

Page. Chart showing functions of Bureau facing— 17

T. Functions, organization, and location 17

1. Definition of standards 17 Standards of measurement IS Physical constants (standard values) 18 Standards of quality 19 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 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 The collection of fundamental data for the industries 22 Training of experts in various industrial fields 22

4. Relation of the Bureau's work to the Government 2:! Comparison of standards of other Government depart- ments with those of the Bureau 2:'» Performance of tests and investigations and the collec- tion 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. Organization 25

6. Location 26

II. Scientific and technical divisions ^ 27

1. Weights and Measures 27 Length 27

Investigation of apparatus and standards 27

Investigations in testing of block gauges 27

Investigation of standards and means of comparison 28 Design and construction of instruments 28 Graduation of line scales 28 Routine testing of length standards 28 Recommendations for year 1920-21 29 Publications 29

Visitors and travel 29 Mass 29 Requests for tests - 29 Prompt handling of tests 29 Standards for States and manufacturers 30 Pyroxylin plastics 30 Improvements in observation and computation forms_ 30

Personnel 30 Time 31 Testing 31 Railroad precision pocket watch specifications 31 Stop watches and chronographs 31 Publications 31 Travel 31 Future work ' 32

3
4 CONTENTS.

II. Scientific and technical divisions—Continued.

1. Weights and Measures—Continued. Page. Capacity and density 32 Routine testing 32 Capacity and density determinations 33

Visitors 33 Information 33 Recommendations 33

Investigations 33 Additional space required 34 Gas measurement 34

Orifice meter investigations 34

Portable cubic-foot standard 34 New method of measuring low gas velocities 34 Routine testing 35 Consulting work 35 Thermal expansion 35

Tests 35 Carbon steel 35

Stainless steel, monel metal, and stellite 36 Enameling materials 36

Celluloid, etc 36 Brasses 36 Molybdenum 36

Glass 36 Anthropometric instruments 37 Dental research 37 Dividing engine 37 Commercial scales 37 Railroad track scale investigation 37

Specifications for the manufacture and installation of railroad track scales 38

Specifications for scales for weighing grain 39 Master scales 39

Revision of tolerances for master scales 39

Test of locomotive scales 40 Bureau of Standards master track scale 40 Mine scale investigation 41 Cooperation with States and other interests in weights

and measures administration 41 Thirteenth annual conference on weights and

measures 42

Specifications and tolerances for liquid-measuring de- vices 42

Investigation, inspection, and test of miscellaneous weighing and measuring apparatus 43 Technical subjects 43 Additional space required 44 Gauge section • 44 Routine testing of gauges 44 Need for gauge testing 45 New type of projection lantern for gauge testing 45 Sine plate fixture 45 Standard method of measuring wires 46

Investigation of indicators 46 Grinding copper electroplates 46

Publications 46 The National Screw Thread Commission 47 Manufacture of precision gauge blocks 47

Optical projection lanterns for Ordnance Depart- ment of the Army 47 Blocks for experimental purposes 47 Experimental apparatus 47 Exhibition of gauge testing equipment 47 Travel 48 Gears . 48
CONTENTS. 5

II. Scientific and technical divisions—Continued.

1. Weights and Measures—Continued.

Gauge section—Continued. Page. Heat treatment of gauge block steel 48 Tolerances for plain gauges for general engineering

wort 49 Records 49 Weights and measures laws 49

Citations to weights and measures cases 50 Foreign weights and measures 50 Kitchen card 51

2. Electricity 51 Scope of the electrical work 51 Standards of resistance 52 Resistance standards 52 The methods of measuring heavy current resistance standards 53 Resistance of the human body 53 Inductance and capacity 53 Inductance and capacity laboratory 53 Inductance research 54

Ballistic investigations 54 New Mexico report 55 Measurements on the battleship Sao Paulo 55 Submarine mine investigations 56 Study of recent scientific developments in France and England 56

Electrical measuring instruments 56 Testing of electrical instruments 56

Electrical properties of ignition apparatus 56 Cooperation with American Institute of Electrical Engineers 57 New apparatus for electrical instrument testing 57 Magnetic measurements 57 General magnetic measurements 57 Magnetic analysis 58 Magnetic compasses 59 Photometry and illuminating engineering 59 Heterochromatic photometry • 59

Inspection and life tests of incandescent lamps 60

Interlaboratory comparison of life-test rating of incandescent lamps 61 A new reflectometer for the measurement of diffuse

reflection factors 61 Radio research and testing 62 Radio research and information 62 University research cooperation 62 Standardization of nomenclature, etc 62

Publications 62 Exhibits and nontechnical descriptions of work 63 Clearing house of radio information 63 Research program 63 Transmission experiments 63

Variations of wave intensity and direction 64 Measurement of received current and signal intensity 64

Properties of antennas 64

Electron tubes 64

Electron tube measurements 64

Electron tube generators 65 Two-electrode tubes 65 Power rectifiers , 65

Electron tube detectors 65

Amplifiers 65 Radio telephony 66

Insulating materials 67 Phenolic materials 67
6 CONTENTS.

II. Scientific and technical divisions—Continued.

2. Electricity—Continued.

Radio research and testing—Continued. ^aise. Miscellaneous materials 07 Apparatus for measurements upon insulating materials 67 Radio measurements 67 Standards 6S Oscillograph 68 Inductance coils 68 Telephone receivers 68 Miscellaneous measurements '. 68 Radio Engineering 69 Radio direction finder 69 Radio fog signaling 69

Unidirectional radio reception and transmission 69 Radio legislation 70

Electrolysis prevention 70

Electrolysis problem among public utilities 70 Economic importance of the electrolysis problem 71 Inconvenience and hazard due to electrolysis 71

Electrolysis mitigation and related problems 72 Development of apparatus for making electrolysis surveys 72 Corrosion of lead . 72

Investigation of lead cable troubles in St. Louis 73

Electrolysis field surveys . 73 Cooperation with the American Committee on

Electrolysis 74 Safety engineering and safety standards 74 National electrical safety code 74 Engineering work in connection with the safety code_ 75 National electrical safety code in practical use 75

Industrial safety standards 70 Head and eye code 77 Logging and sawmill code 77 Gas engineering 77 Standards for gas service 77

Gas-service standards 78 Gas-appliance investigations 79 National gas safety code 79

Electrical and other service standards 80 Standards for electric service 80 Standards for street-lighting service 81 Standards for heating service 81 Engineering standardization 82 Telephony 82 Studies of systems of telephony 82 Telephone circular S3 Laboratory work 83

Investigation and testing of electric battex-ies 84 New testing equipment 84 Tests of batteries 85 Dry cells 85 Storage batteries S5 Railway signal batteries 87 Storage battery nomenclature 87 Standard cells 87 Radioactivity and X-ray measurements 88 Gamma-ray measurements of radium 88 Luminous materials S8 X-rays 89

Public-utility standards 90

Public-utility investigations 90 Relation of the Bureau to municipalities and public

service commissions 90 General condition of the division 91
CONTENTS. 7

II. Scientific aod technical divisions—Continued. Page.

3. Heat and thermometry 92 Thermometry 92

Clinical thermometers 92 Standard temperature scale 92

Industrial thermometers 93 Melting points of greases ^ 93

Specifications for standard chemical thermometers 94 Testing equipment 94 High temperatures 94

Industrial pyrometry 95 Standard samples for thermometric fixed points 95 Heat treatment of glass 95

Investigations in electronics 96 Heat measurements 96 Vapor pressure of ammonia 96 Vapor pressure of carbon dioxide 97

Specific volume of liquid ammonia 97

Specific heat of sodium-chloride solutions 97 Density and thermal expansion of sodium-chloride

solutions , ^_ 97

Specific heat of gases 97

Testing of thermal insulators 98 Preparation of pure materials 98 Thermodynamics 98 Cryogenic laboratory (low temperature) , 98 Operation of plant 98 Hydrogen liquefier 99 Liquid oxygen for use by aviators 99

Pi re-resistive properties of structural materials 99 Fire tests of building columns 99 Strength of materials at high temperatures 100 Pyrometer lag 100

Fire tests of concrete columns 100

Fire-resistive properties of wall plasters 101 Temperatures attained by protected steel in floor and roof slabs under Are conditions . 102 Automotive power plants, fuels, and lubricants 103

Altitude laboratory 103 Lubrication of automotive engines 104

Cooling problems ! 104 Carburetion 105

Ignition 105 Phenomena of combustion 106 Fuels 106 Dynamometer laboratory 107 Miscellaneous 107

Information, testing, and publications 108

Information, activities in societies, etc 10S Thermometer, pyrometer, and heat tests 108

Publications 109

4. Optics 111 Spectroscopy 111 Wave-length measurements 111 Low-voltage arcs Hi

A new microphotometer 112

Spectroscopic analysis 112 False spectra from diffraction gratings 112 Spectrum tubes 112

Photosensitizing dyes 112

Aerial photography 113

Tests of photographic emulsions 113 Laboratory for special photographic investigations 113 Polarimetry 114 Developments in polarimetric work 114 The rare sugars 114
8 CONTENTS.

II. Scientific and technical divisions—Continued.

4. Optics—Continued.

Polarimetry—Continued. Page. Optical properties of oils 115

Testing of quartz control plates 115 Acidity measurements on refined sugars 116

100° point of the saccharimeter scale 117 United States customs laboratories 117 Sugar and molasses at the smaller ports 118

Definitions and specifications of commercial sugars 118 Color of sugars and sirup 118 Preparation of levulose 119

Analysis of sugar mixtures 119 Raffmose in beet-sugar products 120 Picnometer for viscous materials 120

Testing of molasses 120

Standardization of sugar manufacture 121 Molasses formation 121 Beet and cane molasses 121

Decolorizing carbons 122 Gradation of sugars by sieve analysis 122

Diffusion in beet-sugar production 122 Production of mannite 122

Society of Sugar Chemists and Technologists 123 Composition of sirup 123

Crystallization of sugar 124

Purification of sugars 124 Candy test for sugar 124

Official Baumg scale 125

Supplies for customs laboratories 125 Cooperation with customs laboratories 125 Natural rotation of quartz at high temperatures 126 Adjustment and standardization of polariscopes 126 The natural and magnetic rotations and rotation-dis- persions of sugars 127 Light filters 127 Standard samples 128

Polarimetric testing 128

Polarimetric measurement of strain in glass 128 Commercial process for manufacturing pure dextrose. 129 New cadmium vapor arc lamp for poiariscopic uses 129 Colorimetry 130 General summary of the year's work in colorimetry_ 130

Present status of the color-standards investigation " 131 Standardization of colorinietric nomenclature 132 Spectrophotometric methods 132 The application of rotatory dispersion to colorimetry.

photometry, and pyrometry 134 A new study of the leucoscope 135

Investigation of the spectral transmissivity of dyes 135 The commercial color grading of material in which

color is an important property 136

Investigation of camouflage paints 137 Standardization of three-color process inks and

filters 137

Investigation of the Lovibond color scale as used in grading vegetable oils 137 The correlation of color with its stimulus 137

Investigation of eye-protective glasses 137 The ultra-violet and visible transmission of colored

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

Refractometry and optical instruments

Range-finder investigations
CONTENTS. 9

II. Scientific and technical divisions—Continued.

4. Optics—Continued.

Refractometry and optical instruments—Continued. Fage. " Filming " in optical instruments 139 Triangulation cameras 140 Lens tables 140

Test chart for photographic lenses 140

Resolution chart with variable contrast 140

Specifications for sextants 140

Airplane mapping cameras 141 The optical constants and chemical composition of

optical glass 141 Tests for the purpose of drawing up specifications 141 Design of an oscillograph condenser system 141 Information given 141 Summary of tests 141 Racliometry 142 Glasses for protecting the eyes from injurious radiations__- 142 Constants of radiation of a uniformly heated in- closure 142 Methods of computing and intercomparing radiation data 143 Measurements of the component radiations from the sun and from a quartz mercury vapor lamp 143

Reflective properties of metals and alloys 143

Photoelectrical investigations 143 Information furnished on radiometric subjects, conferences, tests 144

Publications on radiometry 144 Photographic technology 145 Sensitometry 145

Photostat machine paper 146 Large camera and stand 146 Camera for bomb trajectory 146 Interferometry 146 Thermal expansion of glass 146

Physical properties of dental materials 146 Standardization of precision gauges r 147 Seasoning of gauge material 147

Radial- expansion of fine wires 147 Information given. Publications 147

Searchlight investigation 148 Transmission of the atmosphere 148 The diffusion of light by the atmosphere 148 The contrast sensibility of the eye 148

Tests of searchlight mirrors 148 Lacquers and enamels for searchlight mirrors 149 Photometry of the high intensity arcs 149 Testing of search lamps and accessories 149

Tests for lighthouse service 149 Information given 149

Publications and reports issued during the year 149

5. Chemistry 150

Physical chemistry 150

Refrigeration materials and problems 150

Purification of materials for special purposes 150

Atlas of hetei- ogeneous equilibria 150

Critical solution temperature work 151

Glass-to-metal joint 151

Glass-to-glass joint 151 Tubing of good quality for glass-blowing purposes 151 Minor problems 151 Electrochemistry 151 Electroplating investigations 152

Metalhirgical chemistry 153
10 CONTENTS.

II. Scientific and technical divisions—Continued.

5. Chemistry—Continued. Page. Gas chemistry 153 The thermal conductivity method for chemical analysis 153 Balloon fabrics 154 Study of laboratory gas analysis methods 154 Hydrogen alarm for use in submarines 154 Bibliography of gas literature 154 Water indicator : 154 Consulting work on the properties and production

of gases 155 New automatic method for gas analysis 155 Work for other divisions of the Bureau 155 Reagents and apparatus 155 Chemical reagents 155 ; Chemical apparatus 156 Platinum research 156 Platinum theft 157 Miscellaneous tests 157

Analytical methods and standard samples 158 Standard samples analyzed 158, Analytical methods 158

Lubricating oils, rubber, paper, textiles, ink, and glue 158 Airplane dopes 158 Rubber 159

Textiles 159 Pearl buttons 159

Fireproofing fabrics 159

Filter paper 159 Clay for paper filter 160

Printing inks 160 Writing and copying inks 160 Stamping, marking, and related inks 160 Typewriter ribbons 160 Carbon papers 160

Glue, mucilage, paste 160 Miscellaneous materials 161

Metals, cement, bituminous materials, etc 161 Chemical work on metals and alloys 161

Antifreezing solutions 162

Boiler waters 162 Bituminous materials 162 Chemical analyses of cement and lime 163 Miscellaneous tests 163

Paint, varnish, and soap 163 Cooperation with Paint Manufacturers' Association— 163 Interdepartmental Committee on Paint Specification

Standardization 163 Chemical testing and publications 164 Chemical testing 164

Publications in chemistry 164

6. Engineering physics 166 Engineering instruments and mechanical appliances 166 Water-current meter rating station 166

Calibration of instruments 166 Hub odometers 166

Tests of thermostatic heating valves 166

Investigation and tests of fire extinguishers 167 Miscellaneous tests and examination of appliances— 167 Aeronautic instruments- 167 Clearing house for instrument information 167 Study of foreign instruments 167 Additions to the instrument collection 168

Technical publications 16S Material for instruction courses 168 Salvage of aeronautic instruments 169 Routine testing 169
CONTENTS. 11

II. Scientific and technical divisions—Continued.

0. Engineering physics—Continued.

Aeronautic instruments—Continued. Page. Flight tests on aircraft instruments 169 Conferences with manufacturers 170

Altitude computation 170 Diaphragm investigation 170 Sphygmomanometers , 171 Direction indicators 171 Navigating instruments 171 Altitude effect on air-speed indicators 171 German aeronautic instruments 172 Dummy observer 172 Rate-of-climb indicator 172

Precision altimeter 172 Turn indicator for airplanes 172 Contrast between war and peace activities 173 Aerodynamical physics 173 Resistance of projectiles at high air-speeds 173 Wind tunnel measurements on projectiles 174 Head resistance and stability of aircraft bombs 174

Aerofoil and airplane model tests 17.r> Air resistance of spheres 175 Roof ventilators 176 Measurement of low air-speeds 176 Sound 176

Acoustic properties of building materials 177

Acoustic properties of assembly room 177 The triode drive of tuning fork 177

Precise measurement of small time intervals 177 Cooperation with the War Department 178

Special investigations 178

7. Structural, engineering, and miscellaneous materials 178 Metals 178

Strain-gauge measurements of 350-ton crane 170

Efficiency tests of oxy-acetylene torches for welding

and cutting 170

Fireproof airplane wings 170

Effect of acid on rope . 180

Metallic bellows 180 Cause of failure of a railroad bridge 181 Mexican woods 181 Strength of struts for flying boats 181 Experimental data for design of autofrettage guns 181 Bearing pressure on ball and roller bearings 182 Strength of metal fence posts 182 Fatigue resistance of copper and of iron tube 182

Joint committee on the investigation of sulphur and

phosphorus in steel of the American Society for Testing Materials 183 Committee on heat treatment of carbon steels of the National Research Council 183 Safety code for elevators 1S3 Methods of testing hardness of metals 183 Materials for aircraft 183 Development of remote reading and recording elec- trical strain gauges 184

Special tests 184 Summary of tests 185 Metals 185 Wood 185 Fiber rope and wire rope 185 Other material 185

Calibration of testing machines 186

Miscellaneous 186 Material tested for other divisions of the Bureau of Standards 187

Materials tested for the War Department 187
12 1 CONTENTS.

II. Scientific and technical divisions—Continued.

7. Structural, engineering, and miscellaneous materials —Coutd. Metals—Continued. Page. Materials tested for the Navy Department 187 Materials tested for other branches of the Govern- ment 187 Materials tested for commercial organizations 188

Publications 188 Cement, concrete, stone, gravel, and sand 188 Test of a concrete and hollow tile floor reinforced in two directions 189 Tests of bond resistance between concrete and steel 190 Pouring and pressure tests of concrete 190 Compressive strength of concrete in flexure 191 Volume changes in mortars and concretes 191 Fineness of cement and other materials 192 Stucco 193 Concrete tanks for oil storage 193 Automatic freezing and thawing apparatus 194 Grading of Indiana limestone 195 Freezing tests of sandstone 195 Laboratory tests in relation to durability of build- ing stones 195

Discoloration tests 195

Durability of cement drain tile and concrete in alkali

soils and waters 196 Preliminary examination of a proposed site for a cement plant 197 Measurement of the consistency of concrete mixtures. 197 Centrifugal concrete mixer 198

Accelerators 199 Service tests on concrete floors 199

Effect of storage on cement _ 200 Loss of water in molds 200 Concreting trouble in cold weather 201

Field tests of concrete 201 Wet and dry aggregates 201 Oversanded mixes 202 New experimental cement plant 202 Magnesite deposits 202

Sorel cement 203

Miscellaneous tests and investigations 203

Testing of cement for Government purposes 204 Changes in the branch laboratories 205 Conference on cement specifications 206 Foreign cement specifications 206

Publications relating to cement and concrete 206 Leather 207

Sole leather 207 Harness leather 208 Upper leather 20S Organ and piano leathers 208

Microscopic 208

Special tests 20S Shoe soles 209 Routine tests 209

Specifications ' 209

Publications 209 Miscellaneous 209 Rubber 210

Specifications for automobile tires and inner tubes— 210 Power loss in tires 210 The international standardization of tire sizes 210 Hospital rubber supplies 210. Rubber used in connection with airplane equipment— 210

Fire hose 211 Miscellaneous rubber goods 211 Rubber jar rings for canning 211
CONTENTS. 13

II. Scientific and technical divisions—Continued.

7. Structural, engineering, and miscellaneous materials—Contd. Rubber—Continued. Page. Rubber analysis i 211 Miscellaneous materials 212

Textiles 212

Definition 212 General facilities 212 Microscopy of textiles 213 Nomenclature and definitions of textiles 213 Problems of wool manufacturing 214

Aircraft fabrics 214

Balloon fabrics 214 World cotton conference 215 Waste silk fabrics 215 Abrasion of suitings 215 German substitutes for bui'lap, etc 216 Manufacture of denims at Atlanta prison 216

Specifications 216 Work for Tariff Commission 218 Flameproofing of parachute silk 218

Test specimens for tensile strength of ducks 218 Spanish moss as a mattress filler 218

Investigation of material for sandbags 219

Sail-canvas investigation 219 Shade Gloth 219

Fish-net investigation 219

Sizing compounds — 219

Cotton and woolen goods 220 Heating pads 220 Routine testing 220 Paper 220

Facilities 221 Tearing strength of paper 221 Paper for lime and cement bags 222

Substitute for sand bags 222

Sizing quality of paper 222 Samples for microscopic estimation of fiber content 223

Sulphate-pulp identification 223 Microphotographs of fibers 223 Microscopy of paper-making fibers 223 Paper from unusual fibers 224 Mimeograph paper 224

Specifications for lime for cooking rags 225 Routine testing 225

Miscellaneous information 225 Lubricating oils 226

Standardization of instruments 226

Viscosity of oil blends 226

Friction machines 226 Routine physical tests 226 Chemical investigations 226 Routine chemical testing 227 Cooperative work 227 Lime, gypsum, and sand-lime brick 227 Popping of lime plaster 227 Chemical lime 228 The use of hydrated lime in concrete 228 Measurement of plasticity 228 The bond between mortar and sand lime brick 229 Time of curing of sand lime brick 229 The acoustics of wall plasters 229

Colored plaster 230 Conference on plastering 230

Physical tests of gypsum 230 Standards for design of reinforced gypsum 230 The cracking of gypsum-block partitions 231
14 CONTEXTS.

II. Scientific and technical divisions—Continued.

7. Structural, engineering', and miscellaneous materials—Contd. Lime, gypsum, and sand-lime brick—Continued. Page.

• Cooperation with the American Society for Testing

Materials 231

Visits to lime and gypsum manufacturing plants 231

S. Metallurgy 232 Microscopy and structure 232 Relation of grain size to mechanical properties 232

Conditions affecting the hardness of carbon steels 232

Intercrystalline brittleness of metals 232 Metallographic etching reagents and methods 233

" Deep etching " as a means for metallographic study- 233

Structure of iron and steel at high temperatures 233 The role of manganese in steel 233 Zirconium and other special alloy steels 234 Flaky steel 234 Conditions of pearlite in steel 234

Effect of phosphorus in low-carbon steels 234

Electric-arc welding 234 Copper crusher plugs 23.1 Heat treatment and thermal analysis 235 New equipment 23-1 Effect of heat treatment on properties of structural

steels 23-1 Tensile properties of steels at high temperatures 230 Heat treatment of carbon steel 237 Behavior of hardened carbon and alloy steels on

heating 237 High-speed steel 237 Gauge steels 23S High-speed cutting alloys 23S Thermal analysis 238 Embrittling effects of cleaning and pickling upon

carbon steel 238 Working of metals and miscellaneous properties 238 Bearing metals 238 New foreign alloys 239

Acid-resisting alloys 230 Cushman zinc coating tester 239

Equilbria of tin rich ternary alloys 239 Metal specifications 240 New equipment 240

Precision altimeter -40

Rolling and forging of metals 24'

>

Emissivity of monel metal and constantan 240

Rolling mill investigation 241

Physical properties of pure nickel 241 Corrosion of aluminum alloys 241 Railroad materials 241

Steel rails from ordinary and sinkbead ingots 241 Cast iron for locomotive cylinder parts 242 Thermal stresses in chilled iron car wheels 242 Thermal stresses in steel car wheels 242

Graphitization of white and gray cast iron 243

Electric furnace cast-iron experiment 243 Sulphur and phosphorus in steel 243 Chemical metallurgy : 244 Iron-carbon-manganese alloys 244

Direct method for determining nitrogen 244

Nitrogen in weld metal 24.1 New design for Arsem furnace heater 24.1 Ladle test ingot research • 24.1 Aluminum ^ 24.1 Total gases in steel 24-1 Special refractories 240 Deoxidizer investigation 24G New equipment 24fi
CONTENTS. 15

IT. Scientific and technical divisions—Continued.

8. Metallurgy—Continued. Page. Foundry 246 Experimental and practical castings 240 Molding sand investigation 246 Weathering of art bronze 246

Electric melting furnaces 247 Government bronze and its substitutes 247

Military problems 247 Light armor plate 247 Machine-gun erosion 247 Copper-crusher gauges 248 Metal spraying 248 Manufacture of victory medals 248 German motor trucks 248 Research aid to manufacturers 248 Wrought monel metal parts 248

Die-casting pins 24!) Saw blades 249 Tinned plate 249 Automatic knitting machine needles 249 Manufacture of automobile crankshafts 249 General activities 250

Metallurgical tests 250

Circulars of information 251 Cooperation with technical and scientific organizations 251 Ordnance detail and visitors 251 Travel 252 Typical micrographs on exhibit 252 Correspondence 252 Conferences 253

Publications 254

9. Ceramics 256 Clay products 256 Use of American clays in the white-ware industry 256 Paper clays 256 American clays suitable for the manufacture of graphite crucibles and glass house refractories 256 ' Clays from Palestine . • 257 Study of the drying of clays 257 Study of the " water smoking " of clays 257 The effect of aluminum chloride upon clays 257 Addition of potassium ferrocyanide to clays 257

"Function of caustic soda added to clays 257

Tests of feldspar and flint 257

Effect of ground quartz upon plastic clays 258 Mechanical strength of typical clays 258

Properties of fire brick 25S Ttansverse strength of fire-clay tiles at 1,350° C 258

Structural terra cotta 258

Refractories for the glass industry 259

Porcelain 259

Solubility of frits 259 The effect of molding structure upon the rate of

vitrification of porcelains 259 Equipment 26l> Enameled metals 260 Fish scaling in enamels for sheet metal 269 The relation of composition of enamel to solubility

in acids 260 Study of opacifying agents in enamels 261 Substitutes for antimony oxide in gray coat enamels- 261 Miscellaneous investigations in enamels 261 Refractories 262 Refractory crucibles 262 The heat conductivity of metallurgical refractories— 262 Cooperation with technical organizations 262
16 CONTENTS.

II. Scientific and technical divisions—Continued.

9. Ceramics—Continued.

Refractories—Continued. Page. Cooperation with governmental departments 263 Assistance rendered individual manufacturers 263 Glass 263 Equipment 263 Colored glasses 263

Optical glass 263

Inspection 263 Large lens blanks 284 Miscellaneous work 264

III. The office 265 Accounts 265 Funds and disbursements 265

Staff 265 Appropriation statements 265 Summary of tests- 268 Personnel 268 Personnel of Bureau 269

Eligibles 269

Personnel records 269

Status of work 270

Publications 270 New publications 270 Announcements and distribution 270

Scientific papers 271 Technologic papers 272

Circulars 272 Miscellaneous 273 Mails and files 273 Tolume of mail 273 Indexing and filing 273 Loans of correspondence 273 Property and stores 273 Library 274 Purchase 274 Bids and orders 274

Organization and records 274 Information 274

Technical documents 274

Special reports 275

Distribution of documents and directing of inquiries 275 Analyses and compilations 275

Visitors 1 276

IV. Engineering and construction , 276 Power plant, buildings and grounds, and transportation 276 Operation and maintenance of mechanical plant 276 Operation of plant 276 Need of new power plant 276

Transportation 276

Construction and repair 277

Electrical 277 Plumbing ! 277 Minor construction 27S

Building and grounds 278

Janitors and laborers 278 Watchmen 27S Grounds 278

V. Recommendations 279

Salaries 279 Power plant 270

Specification, inspection and testing of materials purchased by

the Government 280 Cooperation with the industries in investigational work 2S0 Buildings and grounds 2S0 Test car depot 281

NATIONAL BUREAU OF STANDARDS

Washington, D. C.

1920

FUNCTIONS

Development, construction, custody, and maintenance

of reference and working

STANDARDS

and their intercomparison, improvement, and application

in science, engineering, industry, and commerce.

\

10613—com 1920. (To face page 17.)
REPORT

OF THE DIRECTOR, BUREAU OF STANDARDS.

Department of Commerce,

Bureau of Standards,

Washington, July 1, 19£0.

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

Bureau of Standards for the fiscal year ended June 30, 1920.

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. In order to carry out such comparisons, working standards must be prepared which are subdivisions and multiples

of the fundamental standard, and 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 pre- pared before the standard weight of the Government can become

available to the public. Before these working standards, made up of

subdivisions and multiples of the fundamental standard, can be pre- pared, questions as to the methods of comparison arise, which again

involve the solution of difficult scientific problems in connection with

the balance or the methods used. These balances range from that

10613—20—2 17
NATIONAL BUREAU OF STANDARDS

Washington, D. C.

1920

FUNCTIONS

Development, construction, custody, and maintenance

of reference and working

STANDARDS

and their intercomparison, improvement, and application

in science, engineering, industry, and commerce.

L0018 con 1020, (To (aoe page it.)

STANDARDS PURPOSE

STANDARDS OF MEASUREMENT _—

Reference 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, and volume; mass, weight, density, and pressure; heat, light, electricity, and radioactivity,

including quantity, flux, intensity, density, etc.

STANDARD CONSTANTS

Natural 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;

viscosities; 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 maximum

precision and referred to fundamental standards of measure.

To aid ACCURACY IN INDUSTRY through uniform and correct mea To ASSIST COMMERCE IN SIZE STANDARDIZATION of com****'

products;

* mers and To PROMOTE JUSTICE IN DAILY TRADE through systematic ins e and regulation; l0n To facilitate PRECISION IN SCIENCE and TECHNOLOGIC RESEARC

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 in securing 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 wherever uniformity is desirable; To AID LABORATORY RESEARCH BY REDUCING ERRORS and uncer- tainty caused by use of data of doubtful accuracy.

3 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 pertinent to the quality involved, and specific magnitude in units of measure of such significant factors as uniformity, composition, form, structure, and others.

' To 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.

4

STANDARDS OF PERFORMANCE

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

susceptible of measurement.

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

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

5 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 ranges of the pertinent factors denning quality, safety, economy, convenience, and efficiency.

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; To SECURE UNIFORMITY OF PRACTICE where such is practicable, and EFFECTIVE ALTERNATES in other cases.


REPORT

OF THE DIRECTOR, BUREAU OF STANDARDS.

Department of Commerce,

Bureau of Standards,

Washington, July 1, 1920.

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

Bureau of Standards for the fiscal year ended June 30, 1920.

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. In order to carry out such comparisons, working standards must be prepared which are subdivisions and multiples

of the fundamental standard, and 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 pre- pared before the standard weight of the Government can become

available to the public. Before these working standards, made up of

subdivisions and multiples of the fundamental standard, can be pre- pared, questions as to the methods of comparison arise, which again

involve the solution of difficult scientific problems in connection with

the balance or the methods used. These balances range from that

10613—20—2 17
18 REPORT OF DIRECTOR OP BUREAU OP STANDARDS.

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 large number of working standards, all of which must agree with the

fundamental 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, engineering structure, or commercial transaction.

Physical Constants (Standard Values).

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 those

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 phj^sics 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, a paper or a cloth is found by use to be good or poor for a definite

purpose. The questions 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
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 21

Work of the Bureau in an Advisory Capacity.

The Bureau serves in an advisory capacity for those officials of the

States and municipalities charged with the administration of the

laws governing weights and measures. Likewise its advice is freely

given concerning the use of exact standards in all lines of commercial

activity. This information is of the first importance to many of our

industries. As an example it may be stated that the success or

failure of an industrial enterprise may depend upon the securing of

correct information concerning the control of temperature, advice

which can be secured only from such an institution as the Bureau.

A great many inquiries are also received concerning the use of

the various materials of construction, and the Bureau has frequently

assisted in the preparation of specifications on which to base the

purchase of materials of this kind.

Many 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.

In the formulation of safety codes, designed to govern electrical and other construction, the Bureau has taken an active part, particularly in the collecting and study of data, upon the correct interpretation of which the success of such regulations must always depend.

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 indirectly, with the improvement of methods of production or the quality 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 Agriculture do

to the agricultural interests. Many industries are 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 A-alue of the Bureau's work in this respect

is almost entirely unknown to the general public, and yet the Bureau

receives hundreds of letters, as well as many personal visits from
22 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

manufacturers, seeking information as to standards of measurement,

how to use them, how to measure the properties of materials, or

as to the fundamental, physical, and chemical principles involved;

also, what is of even greater importance, how to initiate and carry out scientific investigations and tests on their own account in their

particular fields of work.

The importance of maintaining scientific 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 se'rvice of the trade weights and measure; 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 and measures of trade; the Physikalisch-Technische

Reichsanstalt, covering testing and investigations in connection with

scientific and technical standards other than weights and measures

;

and the Materialpriifungsamt of the Prussian Government, a large

institution devoted to the investigating and testing of structural,

engineering, and other materials.

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

countries.

The Collection of Fundamental Data for the Industries.

During the past year the Bureau's relations to the industries have

been closer than ever before. Many firms have entered upon the

manufacture of goods formerly produced only in foreign countries,

and in this work (much of which is of a pioneer nature in the

United States) hundreds of important questions concerning methods

of measurement and the properties of materials have required solution. In numerous cases the Bureau has helped to solve these

problems through special investigations conducted in its laboratories,

the results of which have been freely given to the industries, with

the result that improved processes have been adopted, resulting in a more satisfactory product and more economical method of production.

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

scientific staff has been largely depleted, and it will be a matter of some time before it can be brought back to the plane of high efficiency

which it has previously maintained. It is to be regretted that during the year covered by this report conditions were such that the

salaries paid the Bureau's experts in all lines of scientific work are

still wholly inadequate, and it is assumed that during the present

year steps will be taken to place the compensation of scientific and
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 23

technical men in the Government service on a scale more commensurate with that paid by scientific institutions and industrial laboratories. Even then the industries should cooperate in every way

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 this it is necessary 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 eveiwday life of all persons. It was in the Government service, however, that the

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

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

Manyi 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 these

branches of the Government, and the service rendered has involved

every department of physics and chemistry covered by the Bux-eau'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

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 Navy 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 importance 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 necessary to the public in

construction work, and every effort is made hy the Bureau to render

its findings available to the public generally. The demands for in- formation of this sort have come from practically all Government

bureaus and establishments, but especially in connection with the

structural work carried on by the Office of the Supervising Archi-
24 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

tect, the engineering branches of the Army, the Bureau of Construction and Eepair of the Navy, the Panama Canal, and the Eeclamation Service.

Advisory 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

are 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 de- partments 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 Govrnment 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 realiz- ing 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,

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

Canal. The General Supply Committee has called upon the Bureau
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 25

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. 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 elasses of standards. For example, the Division of Weights

and Measures has to do with all matters pertaining to standards of

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 concerned 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 Avith 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, but many of the purely scientific questions in- volved 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 investigation, testing, and preparation of
26 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

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 Physics makes investigations and

tests regarding the performance and efficiency of instruments, devices, and machinery. This work includes the testing of water and

other meters, aeronautic instruments, etc., as well as investigations

in aerodynamic physics and the study of sound.

Questions pertaining to the manufacture, specifications, testing,

and use of the metals and their alloys is so important that a separate

division, known as the Metallurgical Division, is provided to deal

with these problems.

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

and accounting, as well as those of the library and information sec- tion, form the Office Division, while those employed in the operation

of the mechanical plant, the various shops, and the care of the buildings and grounds make up the Engineering and Construction

Division.

6. LOCATION.

The laboratories and offices of the Bureau of Standards are located on a tract of about 28 acres in the northwest section of Washington,

on Pierce Mill Road, near Connecticut Avenue, and are reached by

the Chevy Chase car line. They were placed 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 a city. Furthermore, the area of

ground necessary precluded a site nearer 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 in- creased by the location of the laboratories in a section free from the

ordinary disturbances of metropolitan life.
II. SCIENTIFIC AND TECHNICAL DIVISIONS.

i. WEIGHTS AMD MEASURES.

The division of weights and measures is concerned with measurements involving the funda- mental units of length, mass, and time, and such derived or secondary units as area, volume,

density, and pressure. The activities of the division also include preparation of specifications and tolerances for use in connection with standardization of weighing and measuring apparatus; cooperation with States in the preparation, enactment, and enforcement of weights and

measures legislation; the design, improvement, and inspection of weights and measures apparatus, and the carrying out of researches designed to result in more accurate knoweldge of physical constants. LENGTH.

Investigation of Apparatus and Standards.

Considerable headway was made during the past year in the general problem of the investigation of the Bureau's apparatus and

standards in order to have them in first class condition. The

necessity for this investigation arose from the urgency of the test- ing work for the military departments during the war. This work

of readjustment and calibration was begun last year and noted in

the report for 1919.

The precision comparator box has been put into working condition, some obvious defects remedied and plans made for needed supplementary equipment to use in determining the coefficient of expansion

of a precision line standard as well as for other purposes.

Several minor changes were made in the equipment used for test- ing base-line tapes. Parts of improved equipment—cut-ofr cylinders—which were made a number of years ago, have been installed

and have greatly improved the accuracy, speed and general effi- ciency of the work. Certain improvements mentioned in a later paragraph remain to be made.

The methods of calibrating the intervals of line standards were

investigated and as a result some changes were made in the method

employed by the Bureau. This has resulted in a very considerable

saving of time and the liability for mistakes has been much lessened. Investigations in Testing of Block Gauges.

Considerable time was spent during the last half of the year on

the general subject of interference methods of testing gauge blocks.

The general conclusions reached were (a) that the standards used

in checking the blocks must be frequently intercompared ; (b) that

the character of the blocks of Johansson set 9 is not such as would

warrant any conclusions of inaccuracies which might appear from

the comparison of Hoke blocks with blocks of that set; (c) that,

when the Bureau's line standards are more thoroughly recompared

and calibrated, very good values may be given for precision .blocks,

by comparison with line standards.

27
28 REPORT OF DIRECTOR OF BUREAU OE STANDARDS.

Investigation of Standards and Means of Comparison.

The most urgent need of the section is a very fundamental one. The work of putting the precision comparator into the best working

condition should be completed, the temperature control installed,

and the work of intercomparing the Bureau's standards in a thorough and systematic manner taken up. Among the specific details

of apparatus and methods which require attention there may be

mentioned

:

(a) Microscope objectives of precision comparator.

(&) Illumination of microscope.

(c) Temperature control of comparator box.

(d) Temperature control of comparator room. Design and Construction of Instruments.

Several instruments itemized below are rather urgently needed

and the first two should be designed and constructed as soon as

possible.

(a) Comparator for calibrating the intervals of a graduated line

standard.

(b) A small, very simple comparator consisting of a bed, carriage, rack and pinion, and microscope holders for examining and

calibrating sieves microscopically, for measuring intervals on small

scales and other small apparatus. This sort of work is now done on

the dividing engine.

(c) A projection apparatus, similar to the newly developed

screw-thread projection apparatus, for testing seives, provided the

feasibility of the scheme is demonstrated by actual use on a thread

projection apparatus when one is available.

Graduation of Linear Scales.

Frequent calls are made on this section by other divisions of the

Bureau and branches of the Government for the graduation of

special scales. The accuracy and character of these graduations

range from diamond-scratched lines spaced very accurately to deep

cuts in brass of the type often done on a milling machine. The

facilities for this kind of work are entirely inadequate and should

be increased.

Routine Testing of Length Standards.

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

:

Length standards (yard and meter bars) 9 Haeinacytoineters 573 Invar tapes 14

Steel tapes 182 Reinforced cloth tapes ' 115 Spring balances for tapes 4

Sieves 47

Pieces sieve cloth (16.7 square feet) 6

Level rods 5 Polariscope tubes — 3 Miscellaneous articles tested for length 60

Articles tested for angles . 19

Articles graduated 43
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 29

Recommendations for Year 1920-21.

The work is increasing rapidly, and the manufacturers, dealers,

and users are very urgent in their requests for promptness in the

completion of tests. Even by working overtime all the tests can not

be cared for. This increase applies particularly to sieves, haemacytometers, and tapes. (There are apparently some manufacturers

who are using delays of past years as a basis for a propaganda that

material, such as sieves, can not be standardized at the Bureau for

many months, and therefore the customer should accept whatever

the manufacturer wishes to sell him.) Every effort is being made

to simplify and hasten the work, and additional assistance will be

requested for it. Publications.

Circulars 2 and 39 have been thoroughly revised during the past

year, and it is hoped that they will be published within a short time.

Visitors and Travel.

Many manufacturers and others interested in certain phases of the

work have consulted with the Bureau regarding their problems by

correspondence and through personal visits.

MASS.

Requests for Tests. During the past year there was an unprecedented increase in the

number of weights submitted—about 600 in June, with a total of

5,795 for the year as compared with 3,452 for last year, an increase

of almost TO per cent. This is not merely an increase over last year, but is about 60 per

cent more than ever received before, while the large number of

high-precision tests called for and the much larger average errors of the weights tested have increased the work to nearly, if not quite,

double that required on the tests of any previous year. Prompt Handling of Tests. Prompt handling of the test weights was greatly facilitated by the

adoption during March of the policy of making a final report or

certification on each set of weights in the condition in which it reached the Bureau. By no longer holding sets for the maker or

dealer to replace individual weights found unsatisfactory it was

possible to keep the current work well up to date. By the close of

the year all of the long-standing tests had been either completed or put in such shape that they will be completed during the next month.

Since a couple of minor assistants have been secured the work has

gradually been brought up to date. Instead of tests being in the

Bureau from three to five months one-half of the 600 weights received

during June were sent out during the same month.

Another aspect of the same change is shown in the reduction of

the number of weights on hand. On September 1 there were 2,500

weights on hand; on November 8, 2,000; on April 24, 1,300; on
80 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

For the testing of sets of analytical weights a regular routine was

established. This provides for the complete testing of a new set each day, the weights being wrapped and sealed and the certificate written and checked generally on the following day.

By dividing the work so that no person puts all his time on

simple routine processes it has been possible to make the whole work

of the laboratory somewhat more flexible, and to avoid that deadening of interest that so commonly comes from routine work. The

tests carried out during the year were received from the following

sources

:

Standards for States and Manufacturers.

Five sets of primary State standards were tested for the State

of Oklahoma. Important State standards were also tested for

Vermont, Massachusetts, and Missouri, and a set was received from

Texas just at the close of the year. The most important primary standards of two of the largest

makers of weights were tested. Some of these showed changes which

are probably responsible for excessive errors in weights submitted

by these makers to the Bureau. A set was also tested for one of the

comparatively new firms that had been haAung great difficulty with

inaccurate weights.

Pyroxylin Plastics.

As a part of a general investigation being conducted by the

Bureau on pyroxylin (celluloid and similar materials) the absorption of water has been studied for a number of samples of different

thicknesses of this material from different makers. The absorption

by pieces 15 centimeters square and from 0.15 centimeter to 1 centimeter thick was from 1 to 6 grams when the samples were changed

from air of about 35 per cent to air of about 95 per cent relative

humidity.

It takes several weeks for the samples to attain approximate

equilibrium in air when the humidity is changed, and consequently

the investigation is very long drawn out. A group of the heavier

samples has been subjected to humidities from 35 to 97 per cent and back to 52 per cent. Improvements in Observation and Computation Forms.

Further improvements were made in some of the forms used in

routine testing and two new calibration schemes were developed.

This work is of great importance as the proper arrangement of the

forms often makes considerable difference in the time required for

recording and computing the results. The scheme must also provide checks to detect any errors committed.

Personnel.

Eight new assistants have been started in the work of this section

during the year. Of these, three stayed from one to three months.

Percentage. Federal Government

State governments

Educational institutions Outside parties

24

74

65
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 31

Only one assistant has been in the section more than one year. The

training of new assistants and planning the work so as to get the

best results with their limited exiDerience and skill has consumed

much of the time of the experienced workers.

Since this work demands months of training to secure reasonable

efficiency the changes in personnel have very greatly hampered the

work.

TIME.

Testing.

This section has completed the following kind and number of

tests

:

Class A watches 25 Railroad precision watches 50

Engineers' watches (Army) 84 Ship watches 1, 771 Comparing watches 1, 435

Stop watches 7 Wrist watches 11, 372 Deck clocks 1, 491

Miscellaneous 142

Total 16,377

Railroad Precision Pocket Watch Specifications.

A series of observations on watches of various grades under new

conditions, together with information from manufacturers and rail- road inspectors, provided the basis for drawing up a new set of

specifications for testing pocket watches. This " railroad precision " watch test as compared with other tests, is unusually short ; nevertheless, it is possible to classify watches according to their quality

feorrectly by this test, as has been proven later through elaborate

investigations.

Stop Watches and Chronographs.

A number of stop watches and pocket chronographs were tested

quite carefully, using new methods. As a result of this investigation

it was shown that many of the best-made stop watches possess important errors which are directly due to manufacturing methods.

Specifications for purchasing stop watches have been prepared

and are now in use. Publications.

A new circular for jewelers' weights and measures to replace the

circular (No. 43) on the metric carat has been nearly completed.

When the tables in this circular are available, the workers in precious

metals will be able to use the metric system for all purposes.

A few additional tables were prepared for a revised edition of

Circular 47. Travel.

An official visit was made to all of the watch factories in the

United States and five of the general time inspectors of the various

railroads. The information derived from these experts was used

in preparing the specifications for railroad watches referred to
32 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

above. Also, a visit was made to New York and Waterbury, Conn.,

relative to the standardization of watch glasses. At the same time

the needs of the workers in precious metals were studied. This

resulted in the revision of Circular No. 43 referred to above.

Future Work.

About 50 per cent of the work of this section is the testing of timepieces which are being supplied on purchase orders of the Emergency

Fleet Corporation ; this will continue throughout most of the coming

fiscal year. The work of the War Department will continue for some months,

but will be likely to decrease a little from that of the past year. An investigation deemed advisable is the determination of a shorter commercial method for adjusting watches in the factory. At

present one of the largest companies takes nine months from the

time a watch is begun until it is completed. If part of this time can

be eliminated it will be a great public economy.

Also, it is proposed to investigate the practicability of the use

of some of the new metals and alloys in watch construction, including new types of construction. For this work a skilled watch mechanic

will be required.

CAPACITY AND DENSITY.

Routine Testing.

Apparatus. Number

submitted. Tested. Passed.

Burettes

Cylindrical graduates. Cone

Dilution pipettes Flasks

Pipettes, transfer

Pipettes, measuring .

.

Total. Hydrometers

Salinometers Capacity measures

Capacity measures (liquid field standards) . Density

Special apparatus: Babcock glassware

Specific gravity flasks Engler flasks Miscellaneous

982

129

3 1,210

1,572 2,558

263

584

101

3 1,189

1,259 2,198 237

38925

1 1,036 988

1,676

203

6,717 5,571 4,318

216

12018

158

181

670 1238

14929 216

6018

2 146

181

449

5917

Special. 2 Reports.

Sixty- four per cent of the volumetric glassware submitted passed

the test, while of that actually tested 78 per cent passed. This is an

increase of 13 per cent passing test over that reported one year ago. Of the hydrometers submitted, 66 per cent passed test. During the year the number of pieces of glass volumetric apparatus submitted was 57 per cent more than for last fiscal year. The

number of hydrometers submitted shows a decrease of 35 per cent,

due to decrease in the use of alcoholmeters by the Internal Revenue

Service during the fiscal year. While the number of hydrometers

submitted shows a decrease, the amount of time required to test
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 33

these instruments was increased very materially on account of the

greater variety of the hydrometers submitted.

Capacity and Density Determinations.

The number of metal capacity measures tested, certified, and sealed was 149, as compared with 48 the previous year, an increase of over

200 per cent. The density of a nmnber of samples of steel was determined for

the metallurgical division of the Bureau to show the relation in

density change due to a difference in quenching temperature.

Several samples of alcohol (both ethyl and methyl) were examined

and their densities determined in connection with some work done

by the physical chemistry section of the Bureau. Samples of sodium

chloride solutions were examined, the results of which will appear

in a joint paper by the heat division, the chemistry division, and

this section.

Visitors.

Bepresentatives from practically all of the makers and jobbers of

glass volumetric apparatus who submit such goods for test visited

the laboratory during the year in the interest of placing better ware

on the market. Several sent representatives to the Bureau for training, to inspect the methods employed by the Bureau, and to prepare

themselves for more satisfactory work. The Bureau has calibrated

; a number of the working standards used by the makers of glass

volumetric apparatus in their testing rooms.

Information.

This section was requested by the Field Medical Supply Depot of

the War Department to criticize and make suggestions for tolerances

and specifications covering all of the apparatus tested by this section. This has been completed and in practically all cases suggestions were accepted without change. Blue prints were prepared of

the flask standards used by the Bureau and sent to several firms

requesting them for use in their testing laboratories.

Recommendations.

The Bureau, through a circular letter of June 15, 1920, discussed

the advisability of discontinuing the certificate of corrections for

glass volumetric apparatus (with the exception of burettes and

measuring pipettes) . A large number of replies have been received,

and in practically all cases the parties agreed that if the precision

stamp is placed on the apparatus it will not be necessary to furnish

certificates. This proposition is recommended, and, if adopted, will

facilitate the testing of glassware fully 40 per cent. Investigations.

A request has been received from the department of standards

and tests of the National Petroleum Association to determine the

density and thermal expansion of petroleum oils beyond the density

and temperature range as reported in Technologic Paper 77 and

Circular No. 59. The samples for this work are in the laboratory,

10613—20 3
34 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

but work has not yet been started, due to the urgency of the routine

testing.

There are manjr demands for a publication giving the density and

the number of pounds per gallon of such liquids as peanut oil, coconut oil, lard oil, molasses, sirups of various kinds, etc. This

information is apparently needed by the industries of the country

and attempts will be made to prepare such data at once. Additional Space Required.

The work of this section is greatly hampered by the lack of space

to calibrate and store the large quantities of apparatus submitted

for test, and this contributes in no small extent to delay in disposing

of tests. If the work continues to increase as it has in the previous

year, which amounted to more than 57 per cent, it will not be long

before the congestion becomes so great as to completely block the

testing work. The space required for this work is not less than 50

to 100 per cent more than is now available.

GAS MEASUREMENT.

Orifice Meter Investigation.

The investigation of the characteristics of small orifices for air

and gas has been continued, and, although valuable results have been

obtained, the investigation has not been completed.

It is very desirable that the investigation be extended to the large

orifices such as are used commercially in metering enormous quantities of natural gas, air, and other gases. Neither funds nor assist- ance to pursue this very important work have been available. The

cost of this investigation would be only a small part of the annual

saving which it would make possible through the conservation of

natural gas. Portable Cubic- Foot Standard.

The portable cubic-foot standard, developed by this section and

dedicated to the public through a patent, is now being manufactured on a commercial scale by one or more firms, and the Bureau has

cooperated actively in making it available to the public. These

instruments are now being used by a number of different industries.

An investigation has been carried on to determine the applicability

of the portable cubic-foot standard developed by this section to the

calibration of the small-capacity laboratory meters or gas meters

used for testing purposes. The results of this investigation show that

the instrument is very well adapted to this work, as it is easy to quickly and accurately calibrate a test meter by the use of this

apparatus at any of the speeds at which these small meters are ordinarily used.

New Method of Measuring Low Gas Velocities.

The accurate measurement of low gas velocities such as are used

in ventilation is often a matter of great difficulty, and this is especially true when these velocities are below 3 or 4 feet per second.

This laboratory has developed a simple method of measuring such

low velocities which appears to be very promising. Briefly, the
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 35

method consists of placing a dynamic tip in the air current of

unknown velocity and another in an air current the velocity of which

can be accurately regulated and connecting the tips to a suitable

indicator. The secondary air current is then regulated until the indi- cator shows that its velocity is equal to that of the unknown air stream. In the experiments thus far made a glass T filled with

smoke has been used as the indicator. Preliminary results indicate

that velocities as low as one-half foot per second may be measured

by this method with an accuracy of about 2 per cent. Routine Testing.

The routine tests made by this laboratory on gas-measuring apparatus are shown by the following list

:

Portable cubic-foot standards •__ 8 Dry gas meters 7 Wet gas meters 1

Air-flow meters 2

Total 18 All of the gas meters and three of the portable cubic-foot standards were for the use of Government departments. The two air-flow

meters were for use by the department of terrestrial magnetism, Carnegie Institution of Washington. The other instruments were from

commercial concerns. Consulting Work.

A considerable amount of consulting work on gas-measurement

problems has been done during the present year. Those who have

taken advantage of this portion of the section's activities have in- cluded officials of the War Department, Navy Department, other

Government departments, and commercial concerns. THERMAL EXPANSION.

Tests. One hundred and thirteen specimens have been tested during the

year, including research work on steel, enamel, porcelain, celluloid,

molybdenum, brass, alloys, etc. Carbon Steel. The length changes of tempered steel have been studied over the

range 20 to 9o0° C. It is thought that heat treatment near 200° C.

will, in some measure, accelerate the dimensional changes which take

place with time. The results indicate that much of this instability

_

will be removed if the tempered specimen is held at 200 to 250° C. for a few minutes The problem requires additional work to determine the exact maximum temperature and time allowable for this

treatment without serious injury to the hardness. Stable material

is essential to makers of length standards and gauges, and it is ex- pected that the investigations in this field will indicate the best

treatment to secure material of this sort. The investigation of expansivities at the critical points is nearing

completion and will probably be published during the coming year.
36 REPORT OF DIRECTOR. OF BUREAU OE STANDARDS.

Stainless Steel, Monel Metal, and Stellite. An investigation of the expansion of the above metals was undertaken to see if they could be used in conjunction with or in place of

ordinary carbon steel. This research is practically completed and

indicates no large variation of coefficient among these three materials of dissimilar composition. The range of coefficients extends

from 10 to 15 parts in a million per degree centigrade.

Enameling Materials.

This division cooperated with the ceramics division in the study

of spalling or " fish scaling " of enameled ironware. It was found

that one of the causes of this defect is the divergence of coefficients of iron and the enameling compounds, and that by cooling the

enameled vessels slowly it is possible to prevent this rupture between

the iron and the enamel.

Large quantities of enamel ware are rendered useless by the scal- ing of the enamel from the iron body, and this has added considerably to the cost of manufacture and handling. It is hoped that this

investigation will help to remove this difficulty.

Celluloid, etc. A number of cellulose materials manufactured under various

names, such as celluloid, viscolloid, pyralin, etc., were investigated.

The expansion of these materials in all cases investigated was uniformly large and the tendency to permanent shrinkage quite noticeable when heated 30° or more above room temperature.

Brasses. A series of alloys representing all the commercial brasses has been

tested, and a circular describing the work is being prepared for

publication. Equations and curves are given which will enable one

to determine expansion coefficients from the chemical compositions

of the copper-zinc alloys. Numerous photomicrographs showing

metallurgical phases of these representative brasses have been furnished by the American Brass Co., and this firm has lent valuable

aid throughout the research.

Molybdenum.

The nonuniformity of values given for the coefficient of expansion

of this material led the Bureau to attempt an interpretation of these

values. With the cooperation of the Westinghouse Lamp Co., tests were made on slugs of molybdenum. These were later drawn and

reduced to a very small fraction of the original diameter, tests being

made after each drawing. The variations produced by these operations will account for all discrepancies in values. The fact that

mechanical treatment may modify the expansive properties is not new. The problem of the Bureau is to establish the definite rela- tions, if possible, between the factors modifying these properties.

Glass.

The anomalous expansion of glass, occurring a few degrees below

the softening point, which was discovered by the optical division, has

been definitely confirmed by this laboratory. The method of measur-
REPORT OF DIRECTOR OP BUREAU OF STANDARDS. 37

ing specimens employed eliminates all possible errors due to oxidation or chemical reaction at points of contact with specimens. Likewise the error which would occur when specimens soften and start

to collapse under their own weight does not affect the determinations.

Anthropometric Instruments.

The Bureau assisted in designing and constructing some anthropometric instruments which were required by representatives of the

Smithsonian Institution. These instruments were formerly secured

from Europe and are used in detecting certain physical characteristics of different races. Dental Research.

The tests on dental amalgams by this and the optical division have

been completed. Technologic Paper No. 157 describes instruments

and methods for the most precise work in this field. Comparative

data are included which indicate the presence, on the market, of some

materials of very questionable value.

The Bureau is pleased to note improvements and increased activities, looking toward the highest degree of perfection, by numerous

manufacturers.

The Bureau has received requests to extend this research into additional fields of dental science and it is hoped that opportunity

will be found to furnish assistance to the profession in these other

lines, where a large amount of confusion and indefinite data still exist. Dividing Engine.

For various reasons little or no progress has been made on the new dividing engine referred to in the last annual report. In order

to utilize to the best advantage the apparatus that the Bureau has on hand, the present equipment was overhauled and a slightly higher

accuracy obtained. It is hoped that during the coming year it will

be possible to devote some time to the development of an engine,

which is not only needed by the Bureau but also by American in- dustries. At the present time, it is practically impossible to obtain

linear scales of high precision in this country.

COMMERCIAL SCALES.

Railroad-Track Scale Investigation.

The work of the railroad-track scale section has been very seriously

hampered by the lack of sufficient funds to keep the testing equipments in the field at all times and also by the resignations of many

of the men trained in this work who have left the Bureau to accept- more lucrative positions with railroads, scale companies, and other

industries. This turnover of personnel is very undesirable in this

work since special experience is required, and it is difficult to procure

men with the proper education and personal qualifications at the

salaries that are available. As the result of recent resignations

several men must be procured before all equipments can be put in

operation. The congestion on the railroads also prevented prompt

movements of equipments, and in one instance, during the switchmen's strike, one equipment was tied up for nearly a month while
38 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

i lie others were more or less delayed. The combined effect ox the

above causes has been more than equal to the laying up of one of

the three equipments for the full 12 months.

During the first eight months of the year the Bureau continued its work in cooperation with the Railroad Administration and since that

time has been making its arrangements in connection with the American Railroad Association and the individual railroads in the same manner as formerly. No difficulties were encountered as a result of

the return of the lines to private control, the American Railroad

Association having shown every desire to cooperate with the Bureau

along the lines of the former agreement which has now been revived.

It is now necessary to prepare schedules much further in advance

than when the railroads were all operated by the Government, however. The work completed during the year may be summarized as follows

:

le

>f

Scales tested.

Railroad-track scales Industry-track scales Government and State track scales

Total

Number

tested

.

438

114

Correct.

560

Number. Percent.

189

44

1

234

43.2

38.6

12.5

41.8

Incorrect.

Number. Per cent

249

70

7

326

56.8

61.4

87.5

58.2

These tests were made in the following 31 States and the District

of Columbia

:

Alabama.

Colorado.

District of Columbia.

Florida. Georgia. Idaho.

Illinois. Indiana. Kansas. Kentucky.

Louisiana.

Maryland.

Michigan.

Minnesota.

Mississippi. Missouri. Montana.

Nebraska. New Jersey. New York. North Dakota.

Ohio.

Oklahoma.

Oregon.

Pennsylvania.

South Carolina. Tennessee. Texas. Utah. Washington.

West Virginia.

Wisconsin.

Among the scales tested were some of those owned by 88 different

railroad lines and by many industrial establishments. As in the

past, individual reports, including recommendations, were made on

each scale tested to the interested parties. In many instances the

Bureau is advised that its recommendations in the case of defective

and incorrect scales have been complied with and that the scales are now weighing correctly.

Specifications for the Manufacture and Installation of RailroadTrack Scales.

In the preceding annual report reference was made to the subject

of specifications for railroad-track scales. Since that time the most

sanguine expectations have been realized, sinee the specifications

have been officially adopted b}^ the American Railroad Association

;

the American Railway Engineering Association; the United States Railroad Administration ; the Scale Manufacturers Association ; the

National Scale Men's Association; the Bureau of Standards; and,
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 39

with a slight modification to adapt them to the particular use of

weighing grain, by the State of Minnesota. They have been published by the Bureau of Standards as Circular 83, " Specifications for

the Manufacture and Installation of Railroad Track Scales."

Specifications for Scales for Weighing Grain.

In the last annual report reference was made to the subject of scales for weighing grain, a matter of importance in connection with a

case before the Interstate Commerce Commission, Claims for Loss and

Damage of Grain, Docket 9009. Since that time the final hearing

has been held and the decision rendered. The specifications for

scales for weighing grain, prepared by the committee appointed for

the purpose, and on which this Bureau was representee!, were ap- proved by the commission and are indorsed by this Bureau. This

favorable action of the commission taken with respect to the specification appears to be regarded by those interested in the buying

and selling of grain, including country elevators and terminal

markets, as a distinct forward step toward securing the establishment

of proper and adequate facilities for the weighing and handling of

grain.

Master Scales.

The Bureau has continued its work of maintaining the standard of

weight on the various railroad lines by calibrating and adjusting,

when necessary, the master scales located in various parts of the

country. These are the scales which are used to standardize the

weight of test cars employed by a number of the railroads and industries to test the accuracy of their track scales. The accuracy of these

scales is a matter of extreme importance since if not correct the cars

calibrated upon them will not be correct, and the errors will be re- flected in each scale tested by such cars. In the interest of track

scale accuracy the Bureau calibrates all of these scales that are in

condition once in each year. During the last 12 months 14 such tests were made, these including three new master scales just installed.

Special investigations and tests of some of these scales have also been

conducted.

Revision of Tolerances for Master Scales.

As a result of the work of the Bureau in standardizing the railroad

master scales throughout the country, sufficient data have been ac- cumulated to give information respecting the nature of the action of

such* scales, and the accuracy which could be obtained from present

designs—information which did not previously exist. As a result of

a careful study of the data, the tolerances for use in the adjustment

of master scales have been revised ; and these revised values have been

accepted by the committee on scales of the American Railroad Association, and have been adopted by and printed in the proceedings of

the American Railway Engineering Association.

In the new tolerances explicit distinction has been made betAveen

the tolerances for adjustment and the tolerances for maintenance.

The tolerances previously applied were essentially tolerances for adjustment. In the new values for tolerance on adjustment the allowable error for the high loads is less than before, while for the lower

loads they are greater than was previously the case. This change in
40 REPOBT OF DIRECTOR OF BUREAU OF STANDARDS.

tolerance meets conditions found in practice in field work, and the

new tolerance also corresponds in character and value with the re- quirements for which the scales are furnished. The tolerances

adopted are as follows

:

Test load pounds.

Tolerance in pounds.

Test load pounds.

Tolerance in pounds.

For adjust- ment. For maintenance. For adjust- ment. For maintenance.

20,000 3.00

3.68 4.24

4.75

6. 00

7. 36 8.48

9.49

60,000 5.20

5.62

6. 00

6.37

10.40

11.22

12. 00

12.74

30,000 70,000 40,000 80,000

50,000 90,000

Test of Locomotive Scales.

During the first five weeks of the year one of the equipments was

employed in calibrating special locomotive scales used in plants

with which the United States Railroad Administration had contracts in order to assist in the proper settlement of contracts and

claims. This work, which was started in the last fiscal year at the

request of the Railroad Administration, was completed, investigations having been made in plants located in New York, Pennsylvania, New Jersey, Virginia, and Ohio.

Bureau of Standards Master Track Scale. Attention is again called to the urgent necessity of providing for

the installation and housing of the master track scale purchased

several years ago. This is urgently required for the proper operation of all of the track scale testing equipments. Test cars Nos. 3

and 4 must be reweighed every two months or more in order to maintain and assure their accuracy, and this reweighing should be

done on a scale operated and guaranteed by the Bureau. The

200,000 pounds of test weights carried on cars Nos. 1 and 2, which

are used in certifying to the accuracy of every master scale in the

United States, must be repainted and adjusted from time to time

and the equipments overhauled. The Bureau has no present facilities for doing work of this character.

In addition to the needs of the Bureau, the proposed station would

also be used for the standardization of the test cars of all railroads

entering the city in which the scale is located, the calibration of

weights carried thereon, as well as the calibration of all heavy

weights submitted for test by industries or railroads located in the

vicinity. The maintenance of a Government-owned master scale and testing depot at some central point would do more, perhaps,

than any other one thing to furnish a correct standard of weight to be transferred to railroad-owned and industrial scales, to quicken the

appreciation of accurate weights and weighing, and to reduce claims,

allay suspicions, and provide a more stable basis for all business

carried on by weight.

In the opinion of the Bureau the city of Chicago is the most

favorable location in the country for the station, as it would serve a maximum number of railroads and industries.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 41

Mine-Scale Investigation.

This work demands men of much the same qualifications as those

employed upon the railroad track scale investigation. Therefore,

what has been said concerning the hampering of the railroad scale work on account of the difficulty of holding and procuring a suit- able trained personnel applies here with equal force. Resignations

have been so numerous that it will be necessary to recruit and train

several men before this work can again be prosecuted. Strikes also had the effect of curtailing this investigation, the general strike

of the bituminous coal miners rendering necessary a complete cessa- tion of the work, which had been prosecuted vigorously up to that

time.

A total of 221 mine scales were inspected during the months in

which the investigation was carried on. Of these, 72 scales, or 32.6 per cent, were found to be within the tolerance allowed on this class of scales, while 149,' or 67.4 per cent, were in error by more than the

allowable amount.

The experience of the Bureau during the preceding year enabled it to fix as a fair tolerance on these scales 0.4 per cent. This figure is twice the tolerance allowed on railroad-track scales. However, the

conditions under which these scales are installed and operated are very unfavorable to continued accuracy and an analysis demonstrated that no injustice would be done by allowing the error mentioned.

As heretofore, the tests made were found to have a very favorable

effect on continued production of coal. Many of the tests were made

upon the request of miners or operators; in those cases where the

scales were found accurate, distrust and suspicions were allayed in

the minds of the workers and operations continued with better feel- ings on both sides ; in other cases where scales were found to be in- accurate, corrective measures were applied and both parties to controversies satisfied. This work was carried into new mining regions during the year,

tests being made in the bituminous fields of Kentucky, Tennessee,

Ohio, West Virginia, and Georgia,

COOPERATION WITH STATES AND OTHER INTERESTS IN WEIGHTS

AND MEASURES ADMINISTRATION.

This work has been carried on for some years and primarily consists in making the Bureau of Standards a general clearing house

for the dissemination of weights and measures information to the

end that the State and local officials enforcing weights and measures

laws may attain the highest possible degree of efficiency. Without

correlation, laws, rules, regulations, and methods in the various jurisdictions will fail of uniformity, with the result that progress will be

slower than would otherwise be the case and wasted effort the rule

rather than the exception. In the meantime a useless and unnecessary burden must be borne by manufacturers of all kinds of products

and commodities in their endeavors to conform with the varying

requirements of the separate States. National laws would solve many of the most pressing problems,

especially a law giving to the Federal Government the right to pass

upon the types of weighing and measuring devices manufactured for

commercial use. The very great majority of State and local officials
42 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

are in favor of such a law and one or two States have endeavored to obtain some of the benefits to be derived therefrom by State laws

recognizing the decisions of the Bureau of Standards in their jurisdictions. In the absence of Federal law, however, the Bureau is endeavoring to obtain the best conditions possible by the voluntary

cooperation outlined above. The only fund available for such work

is that granted for the inspection of railroad-track scales and other

purposes, and, as is mentioned elsewhere, this fund is inadequate even for its major purpose. While it is recognized that the benefits

of such cooperation are wholly incommensurate with the expenditures involved, it has been found impossible to prosecute it with any

degree of vigor and what little progress has been made has been

through the medium of State conferences and the national annual

conference mentioned hereafter.

Representatives of the Bureau attended State conferences of

weights and measures officials in Maine, Massachusetts, New Jersey.

Mew York, Pennsylvania, and Wisconsin, gave addresses on timely

subjects of importance, and rendered general assistance along the

lines of weights and measures administration. Also, all possible

information was furnished by correspondence where the nature of

the case made it possible to assist in this way. In the case of the

State of Maine which recently passed a law requiring manufacturers

to obtain certificates of approval on their apparatus before it could

be sold in the State, it was found necessary to advise the State authorities and the manufacturers that under present conditions the

necessary inspections and tests by the Bureau preliminary to the

issuance of such certificates could not be undertaken. Similarly,

nothing could be done to assist the State of Texas, which has passed

a permissive law along the same lines. Thirteenth Annual Conference on Weights and Measures.

The annual conference on weights and measures is a meeting of

State and local weights and measures officials who assemble at the

Bureau of Standards for the purpose of gaining information of

value to them in their various jurisdictions and to take action on

matters of importance in their work of inspection of weights and

measures and the enforcement of weights and measures laws. The

thirteenth of these conferences was held at the Bureau on May 24

to 27, 1920.

One hundred and seven official delegates attended from 28 States and the District of Columbia, 22 States, 40 cities, and 29 counties

being represented. Eighty-seven other interested persons registered

and attended the sessions, these representing manufacturers of

weighing and measuring devices, railroads and Aveighing departments, other Government departments, other associations, etc. The greatest interest was displayed in the papers presented and in

the discussions and debates. Among the subjects of especial interest brought before the meeting were sales by net weight, the standardization of loaves of bread and of commodities in package form,

proposed legislation in reference to installation and testing of gasoline pumps, etc. Specifications and Tolerances for Liquid-Measuring Devices.

Perhaps the most important single accomplishment of the confer- ence was the adoption, after very thorough consideration, of final
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 43

specifications and tolerances for liquid-measuring devices. The constantly increasing use of gasoline, oils, etc., is resulting in a very

great increase in the production and use of these machines, and the

demand has resulted in there being put upon the market a very large

number of types, some of which are objectionable on account of the

fact that accurate measurement is not obtained or because their construction is such as to facilitate the perpetration of fraud. The

various State and local departments have encountered the greatest

difficulty in adequately handling the matter, and the need of uniform specifications and tolerances is very urgent. The action of the

conference in adopting a final set of specifications and tolerances

based upon requirements tentatively adopted by the twelfth confer- ence will do much toward procuring the desired uniformity and thus

making possible the securing of accurate and reliable devices in commercial use throughout the country.

Investigation, Inspection, and Test of Miscellaneous Weighing and

Measuring Apparatus.

Investigations, inspections, and tests of scales and special machines were conducted by the Bureau for various other departments

of the Government at their request. The navy yards at Norfolk,

Washington, and Philadelphia, and the Marine Corps at Quantico,

requested the inspection and tests of various scales and weights, and

in pursuance of these requests, 189 scales and 44 weights of various

types and capacities were reported upon. Scales and testing machines were also tested for various branches of the War Department,

the Department of Agriculture, and the Customs Service of the

Treasury Department. Special investigations on scales of various

types were also conducted, to determine their suitability for various

governmental purposes, such as for grading grain in connection

with the enforcement of the grain standards act, for the Department

of Agriculture, and for parcel post use for the Post Office Department. In connection with the inspection work at the navy yards

the Bureau had occasion some time ago to inaugurate an inspection

service at the Norfolk Navy Yard and instruct employees at the

yard in proper methods of test to the end that regular routine in- spections and tests of the weights and weighing devices at the yard

might be made. During the inspections made this year this service was reorganized and strengthened, new report forms were prepared,

and the work put upon a better basis. As a result of the work done

in the Philadelphia Navy Yard this year it is probable that similar

organization work may be requested there. Various forms of large and small capacity automatic scales and

packaging machines of new and unique designs have also been in- vestigated and tested for industrial concerns. In connection with

the preparation of specifications and tolerances for liquid-measuring

devices various pumps and attachments have been inspected and

tested. Technical Subjects.

Many questions of a highly technical nature were handled during

the past year. Owing to their nature, a great many of them represent

work which is not completed, but on which studies rrmst be continued,

in some cases, for several years to come. An idea of the scope and
44 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

nature of such matters may be gained from the following list of

subjects which received attention during the past year:

The effect of temperature on the action of dashpots and other

damping devices: experimental set-up for research on dashpots;

the locking of smooth pistons in smooth cylinders, under high

pressures; viscous flow between two concentric cylinders, the inner one moving; alignment gauges for adjusting knife edges of weighing mechanisms; mathematical relations of interest in connection

with the construction of certain precision variable angle blocks ; the

effect of a change of level on the balance of flexure plate scales and

torsion balances; effect of eccentricity in a piston on the viscous

flow between the cylinder and piston; the test of scales by taking

readings by the method of vibration; a mistaken practice in adjusting grain scales; the precision test of automatic scales; determination of the formula for the error-versus-load curve, in tests made

on master scales ; the deflection of trussed levers, and the proportions

for maximum stiffness ; method for computing the error for any load

from the results of the abbreviated added load test; eccentric cir- cular cams for rectifying pendulum scales ; influence of the stiffness of the tape on the action of cams, in weighing mechanisms; weighing by substitution ; tolerances for automatic dial scales ; the errors

in the notches of scale beams.

Additional Space Required.

The division is greatly in need of a room on the ground floor of one of the Bureau's buildings in which the 10,000-pound precision

platform scale and two equal-arm capacity balances, one 3,000-pound

and one 1,000-pound, can be permanently installed. Such a room

would then be devoted to the repair and calibration of heavy weights

and in addition could be used for the overhauling of the mine-scale

trucks and equipment from time to time. In the past there has been no designated place in which work such as this could be done. The

result has been that the division has been obliged to borrow space from

time to time and frequent movements of the scales and balances has

been found necessary, an extremely inefficient method and one which

has a very detrimental effect upon the equipment. This room must

be readily accessible to automobile trucks so that weights can be

delivered and removed, and should be equipped with an electric crane to facilitate the handling of the large weights.

GAUGE SECTION.

Routine Testing of Gauges.

The number of lots and the number of gauges submitted month

by month during the year are shown in the following table

:

Month.

July August

September.

October Novemher.

.

December .

1919.

Lots, ; Gauges.

35 ; 8

in I 19

18

19

56928

56 473

1.600

159

Month.

January .

.

February. March

April May

June

1920.

Lots. Gauges.

Total.

1912

2129

1610

216

195

4754

291

281

158

3,911
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 45

Of the above gauges, 76 per cent were submitted by Government

departments other than the Bureau of Standards; 7.3 per cent by

the Bureau of Standards; and 16.7 per cent by private concerns. During the year preceding 98.5 per cent of the gauges submitted were

submitted by the various departments of the Government and only

1.5 per cent by private concerns. The total number of gauges submitted during the year previous was 40,630.

The very great decrease in the number of gauges submitted is significant of the tendency for manufacturers to revert to their old

methods of manufacture without adequate inspection as soon as Government supervision is removed.

Need for Gauge Testing.

The need for gauges and gauge inspection did not cease with the

ending of the war. Wherever interchangeable manufacture is car- ried on limit gauges are needed, and the adequacy of the gauging

system employed may be taken as a fair measure of the success at- tained in interchangeable manufacture.

One of the principal reasons why the United States leads the

world in the manufacture of automobiles, typewriters, machine tools,

and other machine products is that manufacturers in this country

have more nearly grasped the importance of gauging in interchangeable manufacture. It has been said that the wonderful production

records made by our manufacturers during the war were due in a large measure to the fact that the United States Government insisted

upon the proper use of gauges. The use of gauges is no less important in peace than in war and should be encouraged and fostered

in every way possible. Manufacturers should not permit themselves

to lapse into their old prewar methods with the resulting decreased

production and increased cost. New Type of Projection Lantern for Gauge Testing.

A projection lantern has been designed and developed of the type

giving a straight projection on a vertical screen. This lantern has a greater magnification than has hitherto been employed for strictty

gauge work and permits the operator at the lantern to see all the

details of the projected image at a screen distance of only 3 or 4 feet. The reflecting prism and mirror of the vertical type of lantern are thus done away with. Furthermore, an arrangement for measuringangles is incorporated in the optical system of the lantern so that the

protractor used with the vertical lantern is not necessary. The

magnification of the lantern is sufficiently high to warrant its use

in the measurement of the lead of thread gauges and the gauge

holder is provided with an arrangement to permit the measurement

of lead by means of gauge blocks and a micrometer screw. Also the

lantern can be readily adapted to use for the optical gauging of

machine products, especially threaded work.

Sine Plate Fixture.

A device based on the sine bar principle has been made, to facili- tate the determination of the angles on profile gauges and templates.

The device consists of two plates fastened to the opposite ends of a cylinder rotating in a V block. One plate is square and has four
46 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

one-half-inch buttons at its corners, the diagonal distance between

centers of buttons being 5 inches. This plate and four buttons are

essentially two 5-inch sine bars at right angles to each other. All

the angles of a template or profile clamped to the other plate can be

determined with one set-up, which is a great advantage over the

ordinary sine bar. Due to the fact that the increment per minute

for the natural sine of an angle is much smaller for angles of over

45 degrees than for angles under 45 degrees, angles greatly exceeding 45 degrees can advantageously be determined by shifting from

one set of buttons to the other and greater accuracy can be obtained

than with a simple sine bar of the same length.

Standard Method of Measuring Wires.

Considerable work has been done in standardizing methods of

measuring the wires used in the 3-wire method of measuring pitch

diameter of thread gauges. It is necessary to know the diameter

and the variation in diameter of these wires to 0.00001 inch. To

obtain this accuracy it is necessary to standardize both pressure and

form and size of the contacts used. One of the Bureau's Anderson

micrometers had been modified to give the desired pressure and contact conditions to measure these wires.

Investigation of Indicators.

An investigation of commercial indicators was started during the

year. Measurements have been made on a few types of indicators

and the hystersis loops plotted. It is to be regretted that no one is available at the present time to devote a large amount of time to

this investigation and work of a similar nature. Grinding Copper Eletroplates,

An investigation of the possibility of grinding copper electroplates was carried on in cooperation with the electro-chemistry section of

the chemistry division. It was found that by the use of a surface

grinder equipped with a suitable wheel and operated at the proper

speed, copper electroplates could be ground to the desired thickness

and planeness for use in a new process of plate making and that the

method was sufficiently rapid to make it commercially feasible. On

the basis of the work done at the Bureau, a plant was installed at the Bureau of Engraving and Printing, duplicating the grinding

equipment used at the Bureau.

Publications.

The following communications have been prepared and issued

during the year

:

B522. Measurement of taper gauges. B523. Thread measuring formulae and the measurement of pitch diameter. B46G and B513 have been revised and a circular has been prepared

for publication giving the results of an investigation and questionnaire on the subject of practical tolerances for plain gauges. The

report of the National Screw Thread Commission has also been

revised and several hundred mimeographed copies prepared and
REPORT OF DIRECTOR OE BUREAU OF STANDARDS. 47

distributed. The various communications of the gauge section deal- ing with the practical problems of gauges and gauging methods

have been in great demand and many hundred copies of these communications have been distributed.

The National Screw Thread Commission.

The National Screw Thread Commission, appointed in accordance

with an act of Congress (H. R. 10852), with the Director of the

Bureau of Standards as chairman and with headquarters at the

Bureau, has completed its principal work, namely the establishment

of standards for screw threads for use in the United States, and

has prepared for publication a very complete report setting forth

the- standards adopted. These represent the best American screw thread practice and involve no important changes except the elimination of unnecessary sizes. The report when issued will be an important contribution to American engineering.

Manufacture of Precision Gauge Blocks.

Twenty-five 81-block sets of precision gauge blocks have been made

during the year and 19 sets delivered to the Navy Department; 15

sets to the Washington Navy Yard and 4 sets to the New York Navy

Yard. The price of these blocks alone, if purchased at the price of

foreign-made blocks of equal quality, would exceed by several thousand dollars the cost of operating the Bureau's shop for the entire year. Optical Projection Lanterns for Ordnance Department of the Army.

An optical projection lantern of the new type already described was built for experimental purposes, and following that an order

for six of these was received from the gauge section, Ordnance Department, U. S. A., of which one was completed prior to July 1 and

the remaining five are now well under way.

Blocks for Experimental Purposes.

About 400 gauge blocks were made for the metallurgical division

for use in an investigation carried out by that division in connection

with heat treatment of steels. Blocks have also been made for the

optical division for an investigation of the effect of various drawingtemperatures on the hardness and permanency of length of hardened

steel. Experimental Apparatus.

The shop has also built other experimental apparatus for use in the laboratory ; for example, the sine-plate fixture, the electrical-contact device for the Anderson micrometer, the magnetic faceplate

for the lead tester, and miscellaneous odd jobs which were needed

from time to time.

Exhibition of Gauge-Testing Equipment.

During the winter and spring of 1920 the Bureau participated

in two exhibits of gauge-testing equipment. The first was held

in New York, February 3 to 6, and the second in Detroit, April

1-1 to 16. At each exhibit manufacturers of gauges and gauging
48 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

equipment were well represented and an excellent opportunity was

afforded for the Bureau to become better acquainted with the men

and organizations most interested in gauging and for them in turn

to become acquainted with the Bureau and its work. Both exhibits were well attended and successful in every way.

Travel.

In July and August, 1919, a member of the gauge section traveled

in France and England in connection with the work of the National

Screw Thread Commission and while there visited the International

Bureau of Weights and Measures; the National Physical Laboratory; the London Board of Trade (standards office) ; and the Woolwich Arsenal. Several manufacturing plants in England were also

visited. The experience gained is of very great value to the Bureau.

In September a trip was taken to New Haven, Conn., at the request

of the Winchester Kepeating Arms Co., to give a talk before their

Engineers Club on the work of the gauge section. Opportunitj7 was also afforded to study the gauging methods employed by that

company.

In the latter part of June two members of the section visited

Detroit, Mich.; Cleveland, Ohio; Flint, Mich.; .and other manufacturing centers for the purpose of becoming more familiar with

the problems encountered by the manufacturers of interchangeable

products and with the methods employed by them in their solution.

Opportunity was also afforded for the manufacturers visited to learn something of the Bureau and its work.

Several other trips were made during the year for the purpose of

installing gauging apparatus furnished by the Bureau for the use

of Government arsenals. Gears.

One of the most important and most difficult problems confronting builders of machine tools and other machinery is that relating

to the design, construction, test, and operation of gears. Comparatively little has been done on the subject, and the solution of some

of the problems involved is of very great importance. It is hoped

that a part of this work, especially that relating to the inspection and

test of gears, may be taken up by the gauge section.

Heat Treatment of Gauge-Block Steel. It has been found at the Bureau and elsewhere that precision

gauge blocks of the accuracy necessary for the most exacting requirements can be made commercially by the process developed at the

Bureau, but that blocks so made do not always retain their accuracy even when properly used or when not used at all. Certain blocks

show a progressive shortening with time. These changes of length,

though of small magnitude, are sufficient to cause uncertainty where

the highest precision and constancy are demanded. An investigation is now under way, in cooperation with the optical division, to determine the proper temperatures for quenching and drawing the

blocks in order that the desired hardness and permanency of length

may be obtained.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 49

Tolerances for Plain Gauges for General Engineering Work.

A subcommittee of the American Society of Mechanical Engineers

has been appointed to study the above subject thoroughly and make

recommendations to the American Engineering Standards Committee

concerning tolerances for plain gauges for general engineering work.

The gauge section is represented on this committee, and it is expected

that the Bureau will have an opportunity to assist in the collection

and classification of data and in the selection of tolerances to be

recommended for adoption.

RECORDS.

The official records of the division, numbering of laboratory record

books, and the assigning of computation number have recently been

placed in charge of this section. A more complete and permanent

method of keeping some of these records has been adopted and

appears to be a very satisfactory one and a great improvement over

the previous record.

The advisability of keeping a more complete record of the standards of the various States is suggested. This would have to be done

in conjunction with the sections which test the standards. A file was made some years ago of the condition of the State standards

from the reports of investigations, made by Bureau representatives,

of weights and measures conditions throughout the States in 1909

to 1911. This record should be supplemented by reports from time

to time from the State officials in charge of the standards and by

adding to the record a report of the State standards tested and their

condition, etc., at the time of test. This section has cooperated closely with the laboratories in shortening their clerical and record work as much as possible by the

use of proper forms and by lending assistance whenever it was possible to do so. Besides supplying stencil copies of numerous forms

which have been in use for some time, assistance has been given in

devising new forms. All of these forms facilitate the work of the

laboratories and in many cases the time previously consumed on

records in the laboratory has been reduced more than half by the use of stencil forms. The amount of time taken to prepare the

stencil eopies is a mere trifle compared with the saving effected in

the laboratories by their use. It has. also been found possible in a number of instances to prepare certificates and reports directly from

the laboratory records, thus saving a large amount of time which was formerly taken to transcribe by hand the necessary data to the

certificate and report forms, these in turn being merely copied by

the office section. Some idea of the saving thus effected will be had

from the statement that as many as 100 to 200 certificates or reports

are prepared at one time directly from the laboratory records.

Weights and Measures Laws.

Eight years have passed since the last compilation of weights and

measures laws of the various States and of the United States was

issued. During this time very extensive changes have been made in

the State laws; old legislation has been amended to meet present

10613—20 4
50 REPORT OF DIRECTOR 01' BUREAU OF STANDARDS.

conditions and the demand for greater protection and accuracy, and

a number of States which had little weights and measures legislation

at the time the last compilation was made have enacted laws upon

broad lines for the protection of the consumer. These changes have

made necessary a complete revision of the last edition. While considerable work had been done from time to time to keep abreast of new legislation, it was not deemed expedient to devote time to the

preparation of a new edition during the war. However, opportunity was not found until last summer to devote much time to the revision

of this work. It was taken up at that time and pushed during the fall and winter with as much vigor as the other work of the section would

permit until the early spring, when matters relating to^the annual

conference on weights and measures had to be taken up. The revision

is now nearly completed and will make a volume considerably larger

than the former edition issued in 1912.

The weights and measures laws upon particular subjects should be

compiled or abstracted, as may seem best in particular cases, so that

a survey of such legislation in the various States can be had at a glance. Information of this kind will be of particular value when a State or a city is considering the drafting of legislation upon these

topics and when enforcing laws relating to commodities which enter

into interstate commerce. Such information has been compiled in a few cases, for instance, in regard to the sale of bread by weight and

laws relating to the marking of the net weight of commodities in

packages. As opportunity affords this work will be pushed.

Citations to Weights and Measures Cases.

Not infrequently requests are received by the Bureau from weights

and measures officials and from other sources for references to court

decisions on weights and measures cases. Opportunities are thus

presented for the Bureau to give assistance to local sealers in a matter in which they are not well versed and in many instances have no

other source from which to obtain the information desired.

Such information is usually required promptly and there is no

time to search the records. As the particular subjects with which

the local sealers are concerned can be anticipated to a large extent

it is desirable that information on such subjects be compiled as early

and as completely as practicable and be added to and revised from

time to time. A beginning has been made in this work, but the

field is a large one and a great deal of work will be required to collate a satisfactory file. The cases are being arranged for easy reference

in three ways, namely, by States, by names of cases, and by subjects.

Foreign Weights and Measures.

The demand for complete and authentic information in regard to foreign weights and measures is constantly increasing; the Nation's

expanding foreign trade has brought this subject more and more

into prominence. The amount of reliable and up-to-date information published on this subject from private sources is not in keeping

with its importance, and there is no government publication available. The subject is an intricate one, requiring careful study, research,

and, in some cases, investigation. A great deal of reliable data can
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 51

be gathered from reports and publications and by correspondence.

It is evident, however, that it would be necessary in some instances

in order to obtain the most reliable data and to ascertain the true

situation, to make an investigation, since different units are used iff different parts of the same country and units of the same name have

varying values in different localities. The Bureau has compiled considerable information from various

sources during the past year, and has endeavored to render as much

assistance as possible in response to inquiries from commercial and

manufacturing concerns and from individuals. This work is a very

important one and will be prosecuted as much as possible, but with

a decreased force and lack of funds for this purpose it will be impossible to give it the attention that its importance and economic

value to the Nation demands.

Kitchen Card.

A second edition of the Kitchen Card, Miscellaneous Publication No. 39, has been issued. This card has met with the hearty

approval of chambers of commerce, home economics departments

of schools and colleges, agricultural societies, weights and measures

officials, etc. Nearly half a million of these cards have been re- quested, but due to lack of funds the Bureau has not been able to supply 10 per cent of this number, although the cost is very low,

about 1 cent each.

2. ELECTRICITY.

The work of this division covers electrical units, standards, measuring instruments, and methods of measurement, including electromotive force, resistance, current, inductance, capacity, conductivity, insulation, magnetic measurements and properties, radioactivity, radiocommunication, and properties, and performance of electrical equipment, such as lamps and batteries. As a result of cooperation with technical societies, testing laboratories, electrical industries, public-service companies, public-utility commissions, municipalities, and engineers in problems

of standardization, including standards of adequacy and safety of service, some of the work

has been extended to cover more than strictly electrical 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 measure- ments are based, including cooperation with similar institutions in

other countries so as to secure international uniformity. This in- cludes 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 institutions that the measurements made in practice are re- ferred back to the standards of the Bureau. Second, a limited
52 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

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 specifications.

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 investigational 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 study of in- sulating materials 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 haA7 e been and are being

developed, methods of measurement are being improved, and 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.

STANDARDS OF RESISTANCE.

Resistance Standards.

The need for better resistance standards is becoming more and more

urgent as the range of electrical measurement is extended and applied in various fields. Especially is there a need for better low

resistance standards capable of carrying large alternating currents and of high resistance standards suitable for use with alternating

currents. Investigations are under way having for their object improvements in resistance standards for both of these purposes.

A new form of construction for .wire resistance standards has been

devised. This involves the use of a new type of noninductive winding on an insulating support and hermetically sealing the coil thus

formed in an insulating case. It has been found that by the use of forced air circulation the heat

dissipated from a given surface at a given difference in temperature

from the surroundings is very much larger than with natural convection. It has been found possible to make noninductive low resistance

standards capable of carrying alternating currents without oil immersion and without making them larger than the oil immersed

standards now in use. The elimination of the oil is not only a great

convenience, but it eliminates the uncertainty incident to its use be- cause of its tendency to develop acids which corrode the resistance

material and thus change the resistance.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 53

The investigation also showed that it was possible to change the

electrical properties of small resistance wire by surface treatment. In many cases this will make it possible to improve the quality of a particular wire which is to be used in the construction of resistance

standards.

Methods of Measuring Heavy Current Resistance Standards.

The problem of measuring the resistance of heavy current standards, using an alternating test current, has been investigated and a method of procedure outlined- A preliminary design of the necessary

equipment for this work has been finished. It is expected that the new equipment for this class of work, when completed, will greatly

expedite the testing of heavy current standards and will facilitate further investigation of means for improving the design of such

standard resistors. Resistance of the Human Body.

Most if not all measurements of the resistance of the human body

previously made have included the resistance and often the apparent

resistance of the skin, where the electrical connections were made.

The values obtained have depended to such an extent upon the condition of the skin, area of connections, and other factors thai no

conclusions could be drawn from them concerning the resistance of

any particular part of the body other than the skin.

By using four connections to the body, and suitable methods of

measurement, resistances have been determined which do not include

the resistance of any of these connections. The values found, using

a test current of low frequency and of only a few milliamperes. have

been definite and independent of the frequency and magnitude of the

test current and other conditions of measurement. Using a hand

and a foot as current terminals and the other hand and foot as potential terminals the resistance found, which is the resistance of

the trunk of the body, for most individuals is between 20 and 30

ohms.

It seems probable that the resistance depends upon pathological

conditions, and if so measurements of the resistance should furnish

a convenient means for indicating changes in those conditions.

The resistance from hand to hand, using some of the fingers of each

hand as current terminals and the others as potential terminals, has

also been measured and it is entirely practicable to measure the

resistance of other parts of the body. The resistances through portions of the skin are not included and consequently the resistance

measured in this way is very nearly the same as that which determines the current in case of accidental connections between the body

and high-voltage circuits, since then the skin is usually severely

burned, so that it no longer has a high resistance.

INDUCTANCE AND CAPACITY.

Inductance and Capacity Laboratory.

The routine testing which is required of this section is increasing

very rapidly. The amount of testing this year is 60 per cent greater

than the amount last year, and considerably more than double that
54 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

of any preceding year. A great majority of the tests can not be

made in any other laboratory in this country. Hence it is important

that the laboratory shall be allowed to expand, so that these tests can be properly handled. At the present time it is frequently neces- sary for a test to wait one or two months because of the large number

of tests which have been requested in advance of it. Inductance Research.

Since most of the time of the personnel of the inductance and

capacity laboratory has been taken up with routine testing work

comparatively little research has been accomplished during this year. A paper entitled "An Integration Method of Deriving Alternating Current Besistance and Inductance of Conductors" has been

published and work has been started on measurements for checking

accurately the formulas given in this paper. Moreover, the for- mulas derived are rather complicated and difficult of computation,

and an attempt is being made to construct a table which will very

greatly facilitate this work.

Ballistic Investigations.

The ballistic investigations which the section has been carrying on

for the Bureau of Ordnance. Navy Department, have been continued

throughout the year. These investigations were carried on at the

Bureau of Standards because of the precision measurements involved,

particularly those of time and pressure. The Navy Department has

provided the necessary facilities for conducting the experimental

work, both at the proving ground and on battleships. The main

problems investigated during the }

T ear have been as follows

:

Study of the Variation of Gun Pressures with Time.—The experimental gauge which was designed last year has been thoroughly tested

in a bomb and has been given a preliminary test in a 5-inch gun.

Curves showing the results obtained have been plotted, and a report

is being prepared for the Navy Department. This work is of the

highest importance and will be pushed vigorously.

Primer Explosion 1'hnes.—The Bureau of Ordnance has furnished

a large number of primers of different ages to be fired. The greater

number of these have been fired in the laboratory, and data have been

taken to determine their deterioration with age. The report on this

subject will be delayed until after more urgent work is completed.

Ejection Velocities.—A method suitable for use on battleships

lias been devised which gives the velocity of the projectile on leav- ing the gun with an accuracy of approximately 1 per cent. It is believed that certain improvements which are now under consideration will give an accuracy of at least one-half of 1 per cent. It is, expected that there will soon be an opportunity for testing this

method in comparison with other methods.

study of Recoil.—New recoil meters have been built which are much superior to those used in the early experimental work. A

very large amount of data is now awaiting computation.

The Acceleration of Recoil.—By two differentiations of the curves obtained by the recoil meter, it is possible to obtain the acceleration

of the gun in recoil. A study of these curves as obtained in the

New Mexico firing shows such considerable variation in acceleration
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 55

that it seemed advisable to stud}' the acceleration more directly.

Hence for the Sao Paulo firing a special accelerometer was constructed. This instrument apparently functioned very satisfactorily,

but as yet the Bureau has not had an opportunity for plotting curves and comparing them with the acceleration obtained from ' the recoil-meter curves. Firing Time Intervals.—The study of the physical firing time

intervals has been continued throughout the year, both on board

and at Indianhead, Md. This has shown how to divide the process

which takes place in the firing of the gun into certain subintervals

to which study can be devoted.

Jump and Whip of Guns.—This work has been continued throughout the 3

rear. New kinemeters have been constructed which gave

better results than those previously used in connection with the ex- periments on the /Sao Paulo these measurements were of special in- terest on account of the very large whip of the turrets. Velocity of the Projectile Inside the Bore of the Gun.—The Coast. Artillery has cooperated in the design of a camera for determining

the velocity of the projectile inside the bore of the gun. The camera

is placed inside a shell and photographs a spot of light as the shell passes down the bore of the gun. In the first trials the lens of

the camera was shattered because of the extremely rapid acceleration

of the shell. New apparatus has been completed which will be

tried in the near future.

This section has been designing apparatus for determining the

velocity of the projectile from observations of the expansion of the

gun. This was tried on the Sao Paulo firing with partial success. However, the apparatus has been considerably improved and it is hoped to be able to try it in the near future under more favorable

conditions. • Blast Investigations —This work appears to be of much less importance now than it did a year ago. It was then believed that

the blast from one gun might influence the movement of the

projectile from the adjacent gun. However, the data which have

been obtained of other phenomena seem to indicate that this seldom,

if over, occurs. Photography of Projectiles in Flight.—A camera has been

designed and built for obtaining pictures of projectiles in flight. It was recently tried out at Indianhead. and gave very excellent photographs of the projectiles. This camera opens very important fields for investigation.

New Mexico Report.

The scientific data obtained for the Navy on the battleship New

Mexico in October, 1918, and July, 1919, have been carefully compiled and a report of nearly 200 pages prepared. The distribution

of this report is in the hands of the Bureau of Ordnance. Navy

Department.

Measurements on the Battleship " Sao Paulo."

The Bureau of Ordnance of the Navy Department requested that

measurements similar to those made at the time of the experimental

firing of the IT. 8. S. New Mexico be made on the Brazilian battle-
56 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

ship Sao Paulo. A party of seven from the Bureau of Standards

went aboard the Sao Paulo in New York on January 16, 1920, and

left her at Guantanamo, Cuba, February 21. The firing took place

, at Guacanayaba Bay, where conditions are extremely favorable for

such work. Every facility was offered to the Bureau's representatives by the officers of the ship, and a large amount of valuable data was obtained. Some of the data have already been compiled but a large part of it has not }

ret received attention.

Submarine-Mine Investigations.

Improvement in Mine Detonators.—At the request of the Bureau

of Ordnance, Navy Department, this section undertook the study of

the improvement of a special type of mine detonator. While this

work is confidential, yet it may be said that a mathematical solution

has been obtained which will be of very considerable importance in

the design of such an apparatus.

Study of Soluble Washers.—The Bureau of Ordnance of the Navy

Department has requested that a study be made of delay devices

suitable for use in submarine mines. They ask that special atten- tion be given to soluble washers. Apparatus has been designed and

experimental work started on certain phases of this investigation.

Study of Recent Scientific Developments in France and England.

The chief of the section returned from France and England July

5, 1919, and immediately prepared a report covering his observations.

This report was blue printed by the Navy Department and quite

widely distributed for the information of their officers. ELECTRICAL MEASURING INSTRUMENTS.

Testing of Electrical Instruments.

The volume of testing for the public was much larger than for

the preceding year, and that for the Government was considerably

less. It was necessary to spend a considerable amount of time in

putting the Bureau's standard apparatus in condition after a cer- tain amount of unavoidable neglect during the war. The testing of instrument transformers has been continued during

the year, and a detailed study of the standard transformers in use by this section is being made to enable the range of testing to be

extended fourfold (up to 100,000 volts) by the use of series connections. This increase in range is very necessary in view of the

high voltages at which large amounts of power are now being trans- mitted.

Electrical Properties of Ignition Apparatus.

A considerable variety of spark plugs have been investigated and

the porcelains used in their construction have been tested as to their

insulating properties, for various branches of the Government, as well as a number of commercial concerns which desired to undertake

the manufacture of spark-plug insulators.

An intelligent study of the performance of ignition apparatus

under various adverse conditions requires a fairly definite knowledge

of the processes going on within the apparatus. Our knowledge of

these processes has in the past been rather scanty, and expressible
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 57

only in extremely complex mathematical formulas. During the past

.year a somewhat simplified mathematical theory has been developed

and found to give results in satisfactory agreement with experiment.

At the request of the Motor Transport Corps of the Army specifications were prepared for the testing of spark plugs, and these have

been adopted by all branches of the War Department. A similar set of specifications for magnetos is in preparation.

Cooperation with American Institute of Electrical Engineers.

At the request of the instruments and measurements committee of

the American Institute of Electrical Engineers, an exhaustive paper was prepared on the subject of the accurac}7 of commercial electrical measurements. This paper treats of the means by which accuracy

may be obtained, such as b}r proper choice of instruments for a given

service and by protection against adverse conditions likely to be

encountered. A number of features of design are treated in their re- lation to the accuracy obtainable. This paper was read and dis- cussed at the February convention of the institute, and copies have

been sent to instrument specialists here and abroad in order to secure

criticisms and additional information which will be used in preparing a revised and enlarged Aversion to be issued as a Bureau publication. The adoption of a standard definition of power factor in polyphase systems is of considerable commercial importance because of

the increasing development of railway and arc furnace loads. At

present different power companies base their charges for power on

different definitions for this quantity, and consequently much con- fusion and injustice has arisen. The Bureau has cooperated with a joint committee of the American Institute of Electrical Engineers

and the Xational Electric Light Association, and a detailed analysis

has been made of the various possible definitions of power factor

and of the related quantity " balance factor." The- results of this

study are incorporated in a paper to be presented at the summer

convention of the American Institute of Electrical Engineers, and

it is hoped that they will satisfactorily reconcile the somewhat conflicting requirements of the conunercial and engineering users of

this term. New Apparatus for Electrical Instrument Testing.

Two commercial electrical instruments having promising features

of construction were studied to determine their suitability as a basis

of design for sensitive pivoted galvanometers. One of these was

selected, and several galvanometers were computed from it. It is expected that the production of these galvanometers will make possible a considerable simplification and reduction in size and cost of the deflection potentiometers now being made from the original

designs prepared by the Bureau.

MAGNETIC MEASUREMENTS.

General Magnetic Measurements.

In addition to the usual routine testing, a method has been developed and apparatus constructed for the measurement of normal

induction and hysteresis at very high A^alues of magnetizing force.
58 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Measurements can be made with this apparatus up to a magnetizing

force of 3,000 gausses. This work has been described in two scientific papers under the titles " Magnetic Testing of Straight Rods in Intense Fields," and " Measurement of Hysteresis Values from High

Magnetizing Forces." A study has also been made of the variation of residual induction

and coercive force with the maximum magnetizing force. It was

found that there are straight-line relationships between £he maximum magnetizing force and the quotients of residual induction and

coercive force by the maximum magnetizing force. These results were presented in a scientific paper entitled " The Variation of

Residual Induction and Coercive Force with Magnetizing Force,"

which is now in press. Magnetic Analysis.

The value of magnetic analysis both in the realm of pure research

and in commercial testing is becoming more and more apparent as the

development of the subject progresses. The need for such methods

in the field of testing is evidenced by the growing interest on the

part of manufacturers and users of steel, and the results of investigations alreadjr completed and now in progress indicate that we may confidently expect great savings, both in life and in money,

when the relationships between the magnetic and mechanical properties of steel are sufficiently well understood to permit of their utili- zation to the fullest extent. The work in magnetic analysis can best be described under four

heads—correlation of properties, thermomagnetic analysis, testing

of steel products, and detection of flaws and inhomogeneities.

Correlation of Properties.—The correlation of the magnetic properties with the structure and mechanical properties of steel is fundamental and underlies all practical applications of magnetic analysis. During the past year considerable progress has

been made in the study of a simple carbon steel of eutectoid composition (0.85 per cent C). Special attention has been given, to the development of the " reluctivity relation " as indicative of the

microstructure. A paper is in preparation presenting the results thus far attained.

The section has been fortunate in obtaining from the metallurgical division samples of a series of pure alloys of iron, carbon, and

manganese. These samples are nearly all prepared for testing.

They will be tested after various heat treatments in order to correlate

the magnetic properties with the various structures resulting from

heat treatment. Thermomagnetic Analysis.—Not only can the magnetic properties

of steel be used as criteria of the structure and properties of steel, but

they can also be utilized to detect structural transformations in steei on heating and cooling. By making simultaneous magnetic and

temperature observations it is possible to determine the temperatures

at which these transformations take place. It is also possible that

information may be gained as to the nature of these transformations.

Apparatus is now being constructed for making such observations

and it is hoped soon to have some preliminary results. Testing of Steel Products.—Although no definite practical applications have been established in the testing of manufactured prod-
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 59

acts, a considerable amount of data has been obtained on the possibility of making useful tests of articles such as razor blades, armorpiercing bullet cores, and the like. The work on bullet cores was

done in cooperation with the Ordnance Department of the Army, and

it has been found possible to differentiate by means of a magnetic

test between bullet cores having different structures and mechanical

properties. The further development of this method for the testing

of steel bullet cores has been requested by the Ordnance Department.

Detection of Flaws arid In homogeneities.—The method for determining the degree of magnetic uniformity along the length of a steel bar which was developed some time ago has been modified and improved and has recently yielded some interesting and valuable results. A series of carbon steel bars was examined Avhich was intended to be used in an investigation on the effect of heat treatment on the

mechanical properties. Certain portions of the material were located

which showed variations in magnetic properties compared with the

rest, and these were cut out so as not to introduce an extra variable

in the experiments.

This method' has also successfully located " soft centers " and seg- regations in bars of high-speed steel, and it is to be given a practical

test at the plant of a steel company which has offered its facilities in

cooperation with the Bureau.

A cooperative investigation with the Navy Department has also

been undertaken for the purpose of adapting the method to the

inspection of stream-line wire for airplanes, and promising preliminary results have already been obtained.

Magnetic Compasses.

A paper is in press on the testing of magnetic compasses. A small

amount of work was done on compasses during the year, mainly in

response to requests from the military branches for specific information regarding materials or design.

PHOTOMETRY AND ILLUMINATING ENGINEERING.

Heterochromatic Photometry.

Probably the greatest difficulties of precision photometry are en- countered in the measurement of lights of different colors. These

difficulties arise from the different estimates of equal brightness,

minimum flicker, or other criteria of balance on the part of individuals of different color perception. The subject of heterochromatic

photometry has assumed increasing importance with the advent of

the highly efficient illuminants of the present time and much work

has been done by many investigators throughout the world, with the

end in view of establishing a satisfactory method of procedure for

these measurements. In order to assemble the results of these ex- periments in such form as to provide easy reference to all articles of

value on this and directly related subjects, a search was made of all available periodicals and textbooks, and a complete index of the

subject was prepared with abstracts of all important articles and a convenient system of cross reference.

There is thus available a resume of what has been accomplished

and- a ready means of deciding upon the- course of future experi- ments. Pursuant to these activities a new series of experiments has
60 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

been begun, continuing work along the line carried out in the re- search made several years ago at the suggestion of the Illuminating

Engineering Society. This research included measurements involving color differences on a flicker photometer and a contract photometer. The present study has been begun by the calibration of a

series of blue glasses of graded densities at several illumination

levels. Eventually these glasses will probably be sent to other laboratories for similar tests, and from these comparisons additional data

of value regarding reproducibility, precision, and correspondence of

results by the two methods of photometry should be obtained.

Inspection and Life Tests of Incandescent Lamps.

Departments of the Government placed orders for about 1,500,000

lamps during the year. This reduced quantity, which is considerably

below the prewar normal of over 2,000.000* may no doubt be ac- counted for by accumulation of stocks of lamps carried over from the

high averages of war-time production and the overflow of lamps

already ordered and manufactured just previous to the armistice.

Quantity figures, however, are of a different significance than for- merly, because of the increasing use of the larger and more efficient units. For example, the average gas-filled lamp on these orders

gives as much light as six vacuum tungsten lamps of the common

40-Avatt size, and, by a similar comparison, a single 1,000-watt gasfilled lamp is equivalent to 50 of the 40-watt lamps. Consequently,

although in point of numbers orders for gas-filled lamps have

reached only 16.5 per cent of the total for large tungsten lamps, the

corresponding money value is about 45 per cent. As large tungsten

lamps comprise somewhat oyer 80 per cent of the grand total of all classes, it is estimated that at least half of the total illumination

realized from lamps on these orders is furnished by gas-filled lamps.

In view of the unusual requirements of lamp service in some departments, this is a creditable showing. Orders for carbon lamps and

for those of the miniature class made up the remaining 20 per cent

in the proportion of about three to two. Inspections to a total of about 1,200,000 were handled by the

Bureau inspector at the factories of the contractors. The one in- spector has been able to give prompt attention to all lamps on which

inspection was required, but any considerable increase in the quantities ordered will necessitate the help of an assistant inspector in

the field for at least a part of the year. About 2,070 lamps were completed on the life test. This total in- cludes 292 miniature lamps operated on the new racks and 163 of

the same class, but rated at 80 to 130 volts, which were tested in

adapters on the regular lamp racks. Of the remainder, 1,165 were vacuum tungsten, 225 gas-filled tungsten, and 325 carbon lamps.

The new life-testing equipment for miniature lamps is so arranged

that tests may be made at any voltage from to 24 and on either

direct or alternating current. The primary winding of a 1 kilovoltampere induction feeder regulator is connected to the 120 volt mains,

and it in turn controls the primary of a 10 to 1 step-down trans- former. Three of these regulators are in operation. There are also three transformers of 1,600 watts, 50 cycles, two of which step down

from 120 to 4 volts and the third from 120 to 2 volts. By control of
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 61

the primary voltage of these transformers the fractional voltages for

life tests of flashlight lamps may be obtained.

For the direct current tests a number of Edison storage batteries

rated at 6.5 volts, 30 amperes, 150 ampere-hours are available. The

alternating current equipment is most convenient and economical for use during the regular testing season when the 120-volt alternator is in operation for tests of other lamps. The direct-current equipment

is well adapted to operation during the summer months when the

relatively small load of miniature lamps makes it inadvisable to supply current from the alternator.

Besides the regular inspections and tests, data upon the quality of

lamps supplied by two prospective bidders on Government contracts were obtained and reported to the General Supply Committee. These

results were given due consideration by the committee in making

awards.

Interlaboratory Comparison of Life-Test Rating of Incandescent

Lamps.

During the year the Bureau participated in two interlaboratory

comparisons of ratings of lamps for life-testing purposes. Before

the lamps are put on the racks for the burning tests they must be

very carefully tested for candlepower and efficiency, since the life of

a lamp depends on the efficiency at which it is burned. Life tests are usually made at efficiencies higher than normal in order to get

results quickly, and since an error in the intial rating of the lamp

makes an error several times as great in the corrected life, it is evi- dently very important to have the initial rating correct. There are

a number of laboratories in this country doing work of this nature,

and these tests were initiated to compare the ratings assigned to lamps

by various laboratories. A number of lamps were measured in several of the laboratories, and the results were then compared. Later

a much larger group, consisting of about 120 lamps, was submitted

to the Bureau for similar tests. They were given a precision standardization, and were then measured in the same manner as ordinary

life test lamps. They are now being measured in the other laboratories, and will later be returned to the Bureau for rechecking. It is hoped that by such tests the various laboratories may be brought into

closer agreement.

A New Reflectometer for the Measurement of Diffuse Reflection

Factors. The measurement of the light reflecting value of walls and ceil- ings is of great practical importance in the design of lighting

installations. The measurement of reflection factors of other surfaces is also desired at times. In the past there has been no simple

and accurate instrument for this purpose, and all such measurements

had to be carried out in the laboratory. Even then they were often

incorrect. Several years ago the theory of an absolute reflectometer

using the principle of the integrating sphere was worked out and

an experimental instrument was constructed. During the past year

this reflectometer has been very thoroughly tested and found to give

accurate results. The instrument can be adapted for use with a portable photometer and can then be used anywhere for the measure-
62 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

ment of the reflection factor of any accessible surface. For ex- ample, accurate measurements can readily be made on the walls

of a room, so that it is not necessary to prepare special samples of

the wall finish for laboratory measurements. A scientific paper

describing the instrument is now in the press and will be issued

shortly.

RADIO RESEARCH AND TESTING.

Radio Research and Information.

The special research work undertaken for the Signal Corps in

1919 was completed. This included the following problems: Harmonics in electron tube generators, critical study of Signal Corps

testing sets for electron tubes, input impedance of tubes used in

amplifiers, detector action of receiving tubes, variation of direction

of radio waves with time and the surroundings of the receiving

aerial, properties and design of coil aerials. Reports were made to the Signal Corps, including 30 technical reports.

Since the completion of the Signal Corps work a wide range of

research work has been carried on upon radio wave phenomena,

antennas, electron tubes, amplifiers, radio telephony, insulating materials, and numerous radio instruments and measurements.

University Research Cooperation.

Assistance was rendered a number of universities in connection

with research on radio problems. Transmission experiments on

properties of radio waves were carried on with one institution.

Research problems were suggested to a considerable number of

university workers upon such subjects as electron tube detectors,

electron emission, circuit design for radio telephony, electron tube

measurements, and wave radiation. Information was given on

laboratory equipment. Technical reports and miscellaneous information were supplied to a number of inquirers. Criticisms were

prepared on a few scientific papers and books which were submitted.

Advice was given on radio textbooks. " The Principles Underlying

Radio Communication," which was prepared at the Bureau last year,

is coming into wide use as a textbook both for elementary elec- tricity and radio.

Standardization of Nomenclature, etc. Studies were made of current practices in radio terminology, abbreviations, symbols, and notation. Information on this subject was

furnished to a number of inquirers, and a standard terminology was

adopted for use in the laboratory. The general adoption of standards of this sort was furthered by cooperation with the Standardization Committee of the Institute of Radio Engineers.

Publications.

A list of the radio publications of the Bureau was prepared. Lists were prepared of the technical reports of the laboratory; these re- ports, describing much of the research work that has been done, are

available in limited number and have been sent upon application to

specialists who are engaged upon the subjects treated. Publications

have been issued or are in preparation on the various researches
REPORT OF DIRECTOR OF Bl'REAU.OF STANDARDS. 63

described below. Second editions are in preparation of the two

principal publications of the laboratory, Circular 74, "Radio In- struments and Measurements," and the textbook, "The Principles

Underlying Radio Communication."

Exhibits and Nontechnical Descriptions of Work.

Many persons have visited the radio laboratory. The laboratory

and certain exhibits have been specially equipped for the information

of visitors, and have thus been of considerable educational value.

Three lectures of popular grade were given on the principles of

radio telegraphy and telephony. Thirty-seven nontechnical reports on the radio work were prepared, and a general description entitled

" Bureau of Standards' Radio Work " was published.

Clearing House of Radio Information.

In prosecuting its research work, the radio laboratory has accumulated a large amount of technical information which has been care- fully filed and has been found to be valuable for the use of the public.

A file of references to radio articles and periodical literature is maintained and contains 7,500 references. Weekly reference lists are pre- pared. A subject classification for the whole radio field has been

devised and discussed with various specialists. It has been used to index correspondence, reports, references, and data of many kinds.

A number of bibliographies on special subjects have been prepared,

particularly extensive ones on insulating materials and electron tubes.

Copies of about 1,000 patent specifications have been secured and

filed and comprehensive lists of these prepared on specific subjects.

A considerable part of the work is consulting service and the

preparation of technical letters. The information furnished by letter and to visitors has been on such subjects as insulating materials,

crystal detectors, cathode-ray oscillograph, electron tubes for particular purposes, amplifiers, radio telephony, testing .methods, highvoltage direct current generators, mica condensers, measurement of

capacity, theory of radiation of electric waves, and general information and photographs and other material on the radio work of the

Bureau.

Research Program.

Definite programs of work have been prepared covering an extensive field of research, which is necessary for the advancement of

radio and the general field of electrical communication. Statistics

show that the growth of radio industrjr and operation has been very

rapid in comparison with the accomplishment of necessary research.

The Bureau is finding it difficult to do its share of this research work

because of serious losses of personnel. " One of the principal needs at present is the publishing of the large amount of technical and scientific data which is available.

Transmission Experiments.

Transmission experiments were carried on, the current in both

transmitting and receiving sets being measured. A special type of

electron-tube transmitting set designed at the Bureau was used in

these tests as well as a spark set. The same transmitting equipment was used in experiments to assist the Aerial Mail Service of the
64 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Post Office Department in developing airplane radio apparatus.

Studies were made of the nature and amount of radiation of waves from various types of antennas. A scientific paper describing this

work and giving definite transmission formulas was issued, and two

lectures were given before scientific societies on the same subject.

Variations of Wave Intensity and Direction.

A series of tests was begun, with the cooperation of the American

Eadio Eelay league, to obtain data on the rapid variations of signal

intensity in short-wave transmission. The woi^k has been carried on

since June 1, 1920, the wave length used being 250 meters. Nightly

records of the intensity of signals received from six transmitting

stations are taken by 50 receiving stations. The stations are nearly

all those of radio amateurs and are located all the way from St. Louis

to Boston. Valuable data are being obtained on atmospheric dis- turbances as well as on signal intensity.

Eeports were prepared upon experiments on the variation of direction of waves as observed by a coil direction finder. These included

work on the variation of direction with time and effect of surroundings upon the observed direction of radio waves. Measurement of Received Current and Signal Intensity.

A study was made of the various methods of measuring signal

intensit}' and received current and voltage. Experiments were made

upon the comparative signal intensity from various types of trans- mitting sets which give different signal wave forms, such as sine

wave, damped wave, and interrupted wave of constant intensity.

Properties of Antennas.

Formulas were worked out by which antenna capacity can be cal- culated from measured dimensions. Measurements were made upon

antenna ground resistance. Studies were made of such special types

of antennas as the ground antenna, condenser antenna, and coil aerial. Eeports upon an extensive research on the properties of coil aerials were prepared.

Electron Tubes.

The electron tube is a device deA'eloped within the past few years, which has revolutionized and greatly simplified radio communication. It is used for such diverse purposes as the production and

reception of radio signals, amplifiers for magnifying electric cur- rents and reproducing speech or other sound at great distances, tele- phone relays and repeaters for long-distance telephony, multiplex

telephon}', improvement of railway block-signal devices, the reduction of interference in radio communication, and radio telephony.

Electron-Tube Measurements.

The characteristic properties of typical tubes of various manufacturers have been measured. Permanent circuits have been designed and installed for measuring the important coefficients of

tubes. Progress has been made upon the calculation of the coeffi- cients of tubes from their dimensions. A comprehensive file of in- formation on electron tubes, has been built up. A treatise on
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 65

electron tubes has been outlined in detail and the preparation begun.

This is to give general information on the properties and uses of

electron tubes, including much material hitherto unpublished. Its preparation has involved a special study of the physical phenomena

in electron tubes. Electron-Tube Generators.

One of the principal applications of the electron tube is as a generator of alternating current, particularly for radio frequencies. Advances in knowledge and control of their operation have been made.

The reduction of harmonics is one problem which has been in considerable part solved. The characteristics of a number of French,

British, and American tubes as power generators have been measured. A transmitting set employing electron tubes with alternating- current power supply was designed and constructed; it was used in

experiments on fog signaling and other work. "Two publications

have been issued on this subject.

Two-Electron Tubes.

At the request of the Department of Justice a test Avas made of 50

tubes of the two-electrode type, to determine whether they could act

as generators of alternating current. This question is of vital importance to users of electron tubes, the question being whether the

older two-electrode tube can perform one of the important functions

I of the more recently invented three-electrode tube.

Power Rectifiers.

A great practical problem of radio telephony is the necessity for

a power supply of relatively high direct voltage. One of the meth-

: ods of securing such supply is the use of large rectifier tubes. A

study of such tubes was made, including also the two accessory devices, the transformer system and the smoothing-out system. Ways

were devised to increase the output by using three-electrode instead of

two-electrode tubes as power rectifiers. Electron-Tube Detectors. A practical theory of detector action was worked out leading to the definition of detector coefficients. Methods of measuring the

significant coefficients for any detector tube were worked out. Apparatus was designed and installed for measuring the input resist- ance and other important coefficients of detector tubes. Publications were prepared on the operation of an electron tube as an amplifving rectifier and on the measurement of detection coefficients.

Amplifiers.

Experimental amplifiers of novel types were constructed and meas-' urements made upon them. Assistance was given other Government

agencies in the choice and construction of amplifiers, and both laboratory and field tests were made. Experiments were made on the use

of a small electron tube as a relay in a block signal device for safety

of railroad trains at the request of the Bureau of Safety of the

Interstate Commerce Commission. A scientific paper was issued on

the dependence of the input impedance of a tube upon the load in

10613—20 5
66 REPORT OF DIRECTOR OP BUREAU OF STANDARDS.

the plate circuit. Methods were developed for measuring the important properties of amplifiers as well as their parts, such as trans- formers, telephone receivers, and tubes. Permanent testing circuits were installed for measurements on audio-frequency amplifiers.

Data were accumulated on typical amplifiers.

Radiotelephony.

The principles of radio telephony have been studied in the laboratory and a number of contributions of specialized character have been

made to the improvement of this method of communication. A

modern radio telephone transmitting set utilizes electron tubes, which

perform the double duty of producing continuous waves at ultraaudible frequencies and also altering or modulating the intensity of

these waves in accordance with the wave form of the sound. A

theoretical and experimental study was made of modulation, using

the oscillograph. This work has important applications to highfrequency wire telephony as well as radio telephony. The conditions were determined which limit the permissible values of the ratio

of the carrier to modulating frequencies and thus the number of

conversations that can be carried on. simultaneously over a single

system. A report was issued on the fundamental principles of radio

telephony with electron tubes.

A proposed secret system of radio telephony was investigated.

The experiments furnish a definite rejection of the proposed method

but suggested other possible ways of attaining the desired end. No

opportunity has been afforded, however, of pursuing this work

further.

The theory of resonance circuits was worked out, particularly for

electron tube generating sjTstems. The principles of resonance filters for eliminating ripples and output current were developed. A brief

studjT was made of three-phase power supply to eliminate the need

of rectifiers for high-power telephone sets, with particular attention

to circuits for smoothing out pulsations of the output current. Circuits were designed for eliminating the harmonics of high-frequency

current. Contributions were made to the principles of design of

audio-frequency choke coils and efficienc}' of other parts of the modulating circuits of radio telephone transmitting sets. A research was completed on the principles and uses of large

electron tubes, with only alternating current as the power supply.

This involved building a radio telephone set, using four large power

tubes, two as power amplifiers and two as rectifiers. Eeports were

sent to the Navy Department, for whom the work was done. Assistance was given a Navy experimenter in the design of a simple

radio telephone set using 60-cycle power supply. A 100-watt tele- phone set was designed and built for laboratory, experimental,

demonstration, and transmission work. A report was prepared upon

this set. A number of demonstrations of the radio telephone were given

at the Bureau. In connection with this some important experiments

in the wireless transmitting of music were made. With one form

of apparatus the music is not heard at all at the transmitting station,

but becomes audible at any other place within several hundred miles

by the use of a radio-receiving set. Information was furnished a
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 67

large number of inquirers, including various manufacturers, electric- power companies, and the Forest Service, on radio telephone circuits,

calculations, and methods.

Insulating Materials.

The work on the properties of insulating materials has as its objects improving the design of electrical apparatus, particularly for

radio uses; reduction of power loss of electrical instruments; improvement of condensers for telephone and power uses ; specifications

for insulating materials for electrical purposes and applications to various mechanical and industrial uses; and improvement of commercial insulating materials.

Phenolic Materials.

Measurements were made of the mechanical and electrical properties of a large number of samples of phenolic insulating materials

in the pure, laminated, and molded forms. This material has as its base a varnish which is either bakelite. redmanol, or condensite.

Comprehensive tests were made on the machining qualities of the

materials. A research has been in progress on the effects of moisture,

weather, and time. Bimonthly measurements on certain samples have

shown changes as great as 40 per cent in electrical properties. It has

been found that considerable variations in the material occur as furnished at different times by some of the manufacturers. One

result of the work has been that some improvements have been made

in the material by manufacturers.

Miscellaneous Materials.

Measurements of the power loss at radio frequencies and other

properties were made on glass, mica, micanite, asbestos, electrose,

celluloid, wood, marble, hard rubber, fiber, paper, electrasote, resins,

halowax, and paraffin. Data furnished by various, manufacturers were compiled. A comprehensive comparative table of the properties

of hard rubber, fiber, and phenolic materials was prepared. Among

the interesting results of experiment were variations of the power

loss with frequency ; this furnishes data of value in research upon

the theory of dielectrics. Apparatus for Measurements Upon Insulating Materials.

Improvements were made in the apparatus used for measuring

radio properties of insulating materials. These included improvement of the high-voltage storage battery used in generating circuits,

additions to the high-frequency resistance standards, additional

capacity screening and shielding, the extension of the frequency

range, and the extension of the range of resistance or power loss measurable by using a perfect condenser in parallel with the test sample. Descriptions were prepared of the methods of measuring

all the important electrical and mechanical properties.

Radio Measurements.

Instruments were standardized for manufacturers, industrial re- search laboratories, universities, engineers, and amateurs including

wavemeters and decremeters, condensers and coils, electron tubes.
68 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

and ammeters. The radio measurements work included also research on methods of measurements and the improvement of radio apparatus, development and improvement of laboratory standards, and

the giving of information on many kinds of radio measurements and

instruments.

Standards.

The basis of capacity measurement has been more accurately es- tablished by measurements upon 10 condensers by the low-frequency

absolute method, with extensive intercomparisons at both high and

low frequencies. A new design of standard condenser has been completed which makes a great advance in the reduction of resistance,

the great effects of A ery small pieces of solid dielectric having been

eliminated. The basis of wave-length measurement has been improved, the laboratory circuits being intercomparecl and wave-length

values established by stepping up to radio from audible frequencies

by means of electron-tube harmonies. Measurements have been

made on a remarkable new type of wavemeter consisting essentially

of a quartz crystal.

Oscillograph.

Improvements were made in the cathode-ray oscillograph ; hot

and cold cathode types of tubes were compared. The principles

of design were worked out and a publication issued. The device was applied to measurements upon quenehed-spark transmitting

sets, electron-tube transmitting sets, and the study of harmonics in

electron-tube generators. Low-frequency oscillographs were used

for radio telephone research, study of telephone receivers, and comparative wave form of signals.

Inductance Coils.

Methods of measurement were developed, formulas for coil calculation and design, and graphical methods of computation worked

out. Theoretical formulas for capacity of coils were developed.

Measurements were made on inductance, capacity, and resistance

of inductance coils, in particular some coils of a new design with

Ioav -capacity. A report was prepared on the extensive measure- ments that have been made on the inductance, capacity, and re- sistance of inductance coils. Telephone Receivers.

Measurements were made to establish a standard audible signal

for the testing of telephone receivers for radio use. Measurements

of just audible current were made by a number of observers. The

condenser transmitter was developed as an artificial ear, and the

thermophone as a standard source of sound. Measurements were made of the sensitivity of telephone receivers for frequencies from

300 to 1,500. Measurements of the impedance at audio and radio

frequencies were begun.

Miscellaneous Measurements.

The measurement of very small alternating currents by the use

of a current transformer was investigated and a report prepared.

Improved thermoelements for measuring small radio currents were
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 69

constructed. Measurements were made on the effect of type of

modulation on continuous-wave currents, for the current not modulated, and for the current with sine-wave modulation and with

rectangular-wave modulation. Contributions were made to the

theory of parallel resonance of coupled circuits. Improvements

were made in methods of shielding radio circuits. It is now j)os- sible to protect a measuring circuit from spurious effects regardless

of the position of the observer or conditions in the generating

apparatus.

RADIO ENGINEERING.

Radio Direction Finder.

Although the development of the radio direction finder or radio

compass, as it is sometimes called, was undertaken by the Bureau

before the war, its use for purposes other than military was delayed

until after the cessation of hostilities. As a result of the Bureau's

early work in this field, the Navy Department has established a large

number of radio compass stations along the Atlantic and Pacific

coasts. These stations are arranged in groups of three or more near

the entrances of important harbors, and bearings are given, upon

request, to approaching ships.

Recent experiments conducted by the Bureau in cooperation with

the Bureau of Lighthouses show that the direction finder may be

used effectively on shipboard. Badio bearings may be taken on radio

stations on shore or on board ship and observations made directly by

the navigator. A complete direction finder equipment has been in- stalled on the lighthouse tender Tulip, which will serve to thoroughly

test the practicability of the device as used on shipboard.

One of the most important applications of radio lies in its use in

the navigation of ships and aircraft. The further development of

the direction finder will materially aid in the solution of the important problems Avhich are already well in hand.

Radio Fog Signaling.

The establishment and maintenance of aids to navigation are important functions of the Department of Commerce. In cooperation

with the Bureau of Lighthouses, the Bureau of Standards has developed and made practical tests of a radio fog signaling system which

promises to be of great assistance to navigation in time of fog or thick weather when light beacons no longer serve their purpose.

The results of a series of experiments conducted under practical

conditions have led to the establishment of three permanent radio

fog signaling stations or radio beacons, one on the Fire Island Lightship, another on the Ambrose Channel Lightship, and the third at the Sea Girt Lighthouse. These stations automatically transmit

characteristic signal letters at frequent intervals during fog, and

ships equipped with direction finders, or so-called radio compasses, can at any time take radio bearings on these stations, the locations

of which are accurately known.

Unidirectional Radio Reception and Transmission.

The increasing use of radio communication for commercial, navigational, and military purposes, and the fact that the available channels of communication in the ether are limited, make necessary the
70 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

development of every possible means of utilizing these channels to the best advantage and with the minimum amount of interference.

A considerable part of the radio engineering work of the Bureau

during the past year has been taken up in the study of this general

problem, and particular attention has been given to the development of simple means of unidirectional reception and transmission.

The method of unidirectional reception has been applied to direction

finding with the result that the sense as well as the line of direction

is obtained in a simple manner. Radio Legislation.

The United States laws governing radio communication are en

forced by the Department of Commerce through the Bureau of

Navigation. The radio laboratory of the Bureau is called upon

from time to time to cooperate with the Bureau of Navigation in

many technical matters which arise in connection with this work.

On account of the rapid development of radio communication

during the Avar, the present international and national laws which

govern radio communication are inadequate and out of date. The

Bureau of Standards, together with the Bureau of Navigation, has

made a general study of the technical requirements of future legislation, and through a committee appointed by the Secretary of Commerce and representing all radio interests of this country, a comprehensive report has been prepared which forms an excellent basis for

future legislation.

ELECTROLYSIS PREVENTION.

ted

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 electricity 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 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
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 71

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 railway 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 S37stems which are not more or less subject at some points to electrolytic 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 dollars, 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 clue 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 inconvenience to consumers of water, gas, and telephone service due to the interruption 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 possibility of electric arcs being formed when

pipes are disconnected or when different pipe sj'stems make momentary contact. Accidents of this kind are rare, but they have sometimes occurred, resulting in the loss 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
72 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

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 them are due to this cause. A water-pipe line weakened by electrolytic 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 during bad fires to increase temporarily the water

pressure in the district adjacent to the fire. It is very obvious that

a badly corroded water main might be capable of withstanding the

normal pressure on the system and thus give no warning of the weakened 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

progress 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

recognizee!.

Electrolysis Mitigation and Related Problems.

In the field of electrolysis mitigation the Bureau's work has been

considerably curtailed for a number of years. During the war it was practically suspended, and since that time funds have not been

sufficient to put it on a normal basis. However, a number of important investigations have been carried on during the past year. Development of Apparatus for Making Electrolysis Surveys.

Throughout the first half of the year the time of one man of the

section was devoted largely to development work on. improved

methods and apparatus for electrolysis testing. Several modified

forms of apparatus for measuring current flow in pipes and leakage

current from pipes were developed and experimented with in a pre- liminary way in the laboratory and some were used in actual field work. The apparatus for making rapid surveys of current flow in

pipes from measurements made on the surface was completed and

made ready for field use. The other apparatus was not completed

because of the pressure of other work, and it is hoped to take them

up and complete them some time during the coming year. Corrosion of Lead.

A considerable amount of work was done on the electrolytic cor- rosion of lead. This work was rendered necessary by the fact that

the previously published work of the Bureau on this subject had

been called seriously into question by engineers representing the

principal cable interests, so that further work was necessary in order

to resolve questions in dispute. The earlier work of the Bureau had

indicated first that the coefficient of corrosion of lead with ordinary

direct current was considerably less than unity, the actual corrosion

being in general only about 25 to 30 per cent of the theoretical

amount, and, second, that under periodically reversed currents of a period not exceeding 10 or 15 minutes the corrosion of lead was

substantially negligible.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 73.

Extensive investigations of both subjects were carried out in close cooperation with engineers of the cable interests who had taken ex- ception to the previously published reports. The result of the investigation was to establish to the satisfaction of the interests con- cerned the correctness of the results previously obtained and published by the Bureau. Some additional important information was

obtained with reference to the effect of moisture on the coefficient of corrosion of lead with direct currents. The investigation revealed

the fact that in the case of lead, as had previously been shown to be

true in the case of iron, the coefficient of corrosion is largely in- fluenced by the moisture content of the soil in which corrosion takes

place, the drier the soil the lower being the coefficient of corrosion.

This inAr estigation has placed on a definite basis the electrolytic cor- rosion of lead under known conditions.

Investigation of Lead Cable Troubles in St. Louis.

Early in the year there was brought to the attention of the Bureau

for the second time what appeared to be a very unusual case of lead

cable failure on the high tension underground mains of the Union

Electric Co. in St. Louis, and the Bureau was urged to investigate

the trouble. In view of the fact that it appeared not improbable that

eleetrotysis might be an important factor in the trouble, the investigation Avas undertaken by the electrolysis section. This investigation was pursued as opportunity afforded, and during the winter a detailed report was submitted to the Union Electric Co. and other

interested companies in St. Louis, in which the various causes of the

failure were fully discussed. The results of the Bureau's investigations have been accepted by the Union Electric Co., but in view

of the fact that the conclusion was reached that one of the principal

causes of the corrosion was the very bad electrolysis condition which

existed for some time after the cable system was installed in 1913,

thereby placing a large amount of responsibility on the railway company, the railway company has not as yet indicated its willingness

to accept the conclusions without question. The railway company is endeavoring to show that the use of fiber conduit was a more important factor than the investigations of the Bureau indicated. In

order to answer this objection more completely, the Bureau is at present gathering information as to the experience of other companies that have been extensive users of fiber conduit for a period of

years. It is expected that this additional information will be at hand

within the next two months, after which a final report can be pre- pared bringing this investigation to a close. Electrolysis Field Surveys.

Two important field surveys have been made by the Bureau during

the period in question, one in Des Moines, Iowa, and the other in

Springfield, Mass. The investigation in Springfield, Mass., was the

resumption of the work done there several years ago and had for its object to determine whether the railway company should continue

operating with the three-wire system or should revert to a two-wire

system Avith suitable substations and insulated return feeders. The

investigation indicated the latter to be the better solution of the elec- trolysis problem. A report has been submitted to the interests concerned, definitely recommending two-wire operation for Springfield.
< 4 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

The second investigation was conducted in Des Moines, Iowa, and

had for its object to determine the effectiveness of the automatic

substation in mitigating electrolysis. In a certain sense this investigation was a cooperative one with the research subcommittee of the

American Committee on Electrolysis, but it was planned and executed

by the Bureau in a manner very similar to previous electrolvsis

surveys made in other cities. Cooperation with the American Committee on Electrolysis.

Early in the year definite arrangements were made with the

American Committee on Electrolysis, which represents all of th

great national associations of utility companies, for cooperative wor

between that committee and the Bureau in conducting an extensive

research in the field of electrolysis mitigation. After this arrangement had been made the committee asked the Bureau to outline a program of research work to be carried out jointly, and such a program was formulated by the Bureau and approved by the committee.

During the last four months a number of "somewhat" extended investigations have been carried out in cooperation with this committee

in a number of cities in the Middle West. This work has been confined almost exclusively to the effect of pipe drainage on underground systems, especial attention being given to the possibility

of joint electrolysis on high-resistance joints and interchange of current between drained stystems. Some attention has also been

given to the three-wire systems of power distribution and also to automatic substation installations as a means of electrolysis mitigation. This joint investigation is an extremely important one, and it is hoped that means will be found for continuing it during the coming year, although it now seems necessary to curtail the work for a time on account of lack of funds.

SAFETY ENGINEERING AND SAFETY STANDARDS.

National Electrical Safety Code.

The Bureau has been engaged for seven 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

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 generally realized, and

also 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. 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. Rules for the construction and maintenance of overhead and

underground lines for the transmission and distribution of electrical

energy and intelligence.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 75

3. Rides fcr the installation and maintenance of electrical ap- paratus and wiring in factories, residences, and wherever electricity

is utilized for light, heat, or power.

4. . Rules to be observed by operators in working on or near elec- trical machines or lines. 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. The varying conditions in different geographical sec- tions 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 re- vised after a general conference of all interests in Chicago in the

spring of 1916. were combined in a single volume. Circular No. 54,

which was published in November. 1916, 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

industry. shows revision and amplification to be to the public advantage.

The last edition has now been revised and copy is ready for re- printing. It is proposed to issue the new edition in pocketbook size and to segregate the discussion under a separate cover from the text of the rules. A pictorial edition of the rules, showing their application by illustrations, and a volume of engineering data, are also planned and have been partially prepared.

Engineering 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

temperatures other than those used in the original published tables,

and steel wires and cables have also been included.

National Electrical Safety Code in Practical Use.

The code has noAv 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
76 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

recommending 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 as a basis

for a merit-rating schedule by casualty insurance interests. Such

schedule rating 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 OAvn practice. It is becoming generally understood that the stability in electrical practice provided by such a national standard conduces greatly to general econ- omy and safety.

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 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.

On December 8, 1919, another conference on industrial safety

codes was held at the Bureau and was attended by representatives

of all interests from many parts of the country. The conference

voted in favor of having safety codes prepared under the auspices

of the American Engineering Standards Committee. It also provided for the formation of a joint safety code committee to prepare

a list of codes already in existence or urgently needed, and to rec- ommend sponsors for preparing and revising these codes.^ Such a committee was organized by the National Safety Council, the Inter- national Association of Industrial Accident Boards and Commissions and the Bureau of Standards. This committee is now known

as the National Safety Code Committee. It has held three meetings and has reported to the American Engineering Standards Committee a list of codes and recommended sponsors. Most of the

recommendations have been approved by the American Engineering

Standards Committee. The codes recommended for sponsorship by

the Bureau of Standards are the following

:

National Electrical Safety Code. National Gas Safety Code (joint sponsorship with the American Gas

Association )

.

National Safety Code for the Protection of Head and Eyes of Industrial Workers.

Combined Electrical Fire and Safety Code (joint sponsorship with the National Fire Protection Association).

National Safety ('ode for Protection against Lightning (joint sponsorship with the American Institute of Electrical Engineers).

National Safety Code for Logging and Sawmill Operations.

National Safety Code for Aeronautics. All of these but the latter have been approved by the American

Engineering Standards Committee.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 77

Heads and Eyes Code.

Two successive drafts of the Safety Code for Heads and Eyes Protection were prepared during the year and circulated for comment.

On March 12 a meeting was held in Philadelphia by the advisory

committee which had been organized for this code and most of the

questionable points were settled. The remaining points have since

been disposed of and a final draft of the code prepared for printing.

A discussion to accompany this code has also been prepared.

Logging and Sawmill Code.

A rough draft of this safety code was prepared from a stud}7 of

existing requirements and our general knowledge of such operations.

Field inspections were made by members of the staff' in the Virginia

woods and later in the South as far as Louisiana, and in Xew York

State and Xew England. As a result of these field inspections and

comments by the Bureau's staff a revised draft of this code will be

circulated for wider comment.

GAS ENGINEERING.

Standards for Gas Service.

The increasing difficulty of obtaining oil and other gas-making

materials, and of financing improvements and replacements of gas

plants, has given rise to a critical situation in the gas industry.

During the year the Bureau has received an unusual number of

requests for assistance from cities which were dissatisfied with their

gas service, and advice has been sought in other cases where, as a means of reducing costs of manufacture, gas companies have appealed for a reduction from the high standards of quality which

have hitherto prevailed in this country. Such readjustments of

standards to meet changed conditions are economically desirable

and in this case practically inevitable, but the effects of such changes

are manifold, and some of them are difficult to foretell. For example,

it is as yet uncertain to what extent the amount of gas used by the

average customer would be affected by a uiven reduction in the heating value of the gas supplied. It is certain that many of the arguments advanced regarding the relative usefulness of gases of different

quality have been based on exceedingly meager engineering or ex- perimental data. It is also certain that the usefulness of any gas

must depend on the proper design and adjustment of the appliances

m which it is burned. Consequently such experimental work on

gases as the Bureau has been able to do during the past few years

has been directed to these two ends: that is. to furnish a better

foundation of definite knowledge regarding the usefulness of dif- ferent gases, on which a fair readjustment of standards may be

based, and to improve the design and promote the proper ad justment

and maintenance of gas appliances in common use. In such unsettled conditions as now exist in the gas industry, when

both operating companies and regulatory authorities have to meet new problems and make decisions based at best on a very limited

fund of experience, the services of the Bureau as a clearing house

of information are especially valuable. Its contact with interests of

every kind in all parts of the country enables it to apply to any

particular local problem the results of experience in other places,
78 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

and thus to save much duplication of effort and of costly experimentation by local authorities "who otherwise would have no means

of knowing current developments elsewhere. Moreover, the Bureau's

established position as an impartial agency has frequently made it possible to improve the relations between the companies, the authorities, and the public, thus opening the way for cooperative effort in meeting the difficulties which have arisen.

In order to strengthen its connections with all interests concerned,

and to make its services of the greatest possible value to all, the

Bureau has formed during the year a consulting committee of gas

engineers, including representatives of State commissions and of

gas companies, as well as independent consulting engineers. In the

revision of Circular 32, " Standards for Gas Service," which b is been

under way during the year, the Bureau has profited greath by the

hearty cooperation of this committee. The tentative manuscript of

the new (fourth) edition was mimeographed and sent out for study

and criticism : after a preliminary revision based on written com- ments was made, the committee met at the Bureau on January 13

and 14. 1920. and discussed fully the outstanding points on which

there were differences of opinion. Although this procedure can not

be expected to bring about complete unanimity, it will give this cir- cular an authority even greater than that which it has previously

had. and is a long step toward the solution of public-service problems on the basis of reasonable economic and engineering considerations rather than by bitter political or legal fights.

The new edition of Circular 32 is now in press, and a separate cir- cular, giving a revised collection of current rules and laws governing gas service, will be ready for the printer as soon as copies of some

very recent State rules are received.

Gas-Service Inspections.

While advice and information have been given by correspondence

to authorities in all parts of the country, the limited amount of field inspection work which could be done has been confined almost entirely to the southeastern section. The Bureau has had frequent

calls, especially from the State commissions of Maryland, Virginia,

North Carolina. Georgia, and Alabama. More or less complete in- spections have been made of the gas plants, and the service furnished

in Annapolis. Cambridge. Crisfield, Cumberland, Easton, Elkton,

Frederick. Salisbury, and "Westminster. Md. ; Anniston, Birmingham,

Decatur". Gadsden. Huntsville, Mobile, Montgomery, and Selma, Ala.

;

Athens, Ga. ; and Durham, X. C. Reports on these inspections have

in general been made to the respective State commissions. In some

of these places the Bureau has been able to show how conditions

might readily be improved to the advantage of all concerned: in

others it could only corroborate the claims of the gas companies that

they were doing ail that could reasonably be expected under the difficult circumstances then existing. Even this assurance from a dis- interested party has. however, some A'alue in such cases in that it helps to create a better feeling and to facilitate arrangements which

may be necessary in order to improve the service. In all this work

care has been exercised not to encroach on the proper field of activity

of private consulting engineers, and in cases where rebuilding or

alterations of plant appeared to be desirable the Bureau has given
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 7ft

only general advice, referring the companies to reputable engineers

for detailed studies and estimates.

Gas-Appliance Investigations.

The investigation of gas-burner design and operation, begun last year in cooperation with the industrial fuel committee of the American Gas Association, has been continued actively throughout the year. This work is an essential preliminary of the investigations which

have been in mind for several years, looking toward improvement

in the efficiency of use of gas. The proper design of air shutter, gas

orifice and burner throat to give the maximum injection of air under

the ordinary conditions of use of gas was the part of the problem particularly assigned to the Bureau. Some months were spent in designing and developing suitable apparatus for making the necessary

measurements of the air and gas, but the equipment developed has

proved so satisfactory that results have been obtained rapidly on

experimental burners representing a wide variation in the dimensions which have to be considered in the design of burners. An ex- tended report of the results so far obtained was presented to the

industrial fuel committee in June.

The work covered in this report was done primarily with refer- ence to industrial burners, but the urgent need for conservation of

natural gas and for improvement in natural gas service as supplied

to households suggested the desirability of extending this investigation to the types of domestic burners used with that gas. Since

transportation of sufficient quantities of gas to Washington was not

practicable, the Bureau of Mines provided space in its Pittsburgh

experiment station, and late in the year experiments were begun there

to find what range of efficiency is actually obtained in the use of

natural gas and what degree of improvement is practicable. This

work has already progressed far enough to show that many appli- ances as used are very low in efficiency and that great improvement

in this respect can readily be made. Specific tests, for example, have

shown that equipment which now makes use of only 10 to 30 per

cent of the heat of the gas can be made to use 30 to 50 per cent. Such increases in efficiency, if generally obtained, would be equivalent to doubling the supply of gas available.

Results of great importance have also been obtained in the design

of natural gas burners to operate on low pressures. It is a common

experience that in very cold weather the gas pressure falls for vari- ous reasons so that the usual gas appliances become practically useless. This investigation has shown that burners can be so designed

as to operate well on natural gas at low pressures such as are used

with manufactured gas; and it is possible that an improvement in

service might be made by installing regulators which would supply

gas at a low and uniform pressure. The adoption of this plan, however, would require considerable changes in gas distribution systems

valued at many millions of dollars, and before it could be definitely

recommended extensive engineering studies would be required.

National Gas Safety Code.

As indicated in last year's report, work on the Gas Safety Code

has been necessarily deferred because of lack of adequate support

for the gas-engineering work. Some progress has, nevertheless, been
80 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

made during the year. Technologic Paper Xo. 133, " Tests of Flexible Gas Tubing." prepared last year, was issued in October. Part

3 of the code, on gas fitting, has been practically completed, and the

Committee on Gases of the Xational Fire Protection Association has

already adopted it with very few changes as the association's rules

for house piping. Part 2 on distribution, is ready for discussion

and has been submitted to the American Gas Association for criti- cism. The first draft of Part 1, on manufacture, has been completed,

and will be prepared as soon as possible for submission to outside

engineers.

In initiating this work the desire of the Bureau was to serve as a coordinating agency in order that the resulting code might be adequate for the protection of gas-company employees and customers

and of casualty and fire-insurance interests, and at the same time be

acceptable to the gas companies and the gas-appliance manufacturing

and selling interests. Since the work was undertaken systematicprovision for such cooperative work has been made through the

reorganization and enlargement of the American Engineering Standards Committee, which has assigned the sponsorship of the Gas

Safety Code jointly to the Bureau and the American Gas Association.

Avoidable accidents, due to ignorance, or carelessness in the use of gas or to faulty installation, result in hundreds of deaths and

the loss of large amounts of property every year. If the code could

be completed and adopted throughout the country an important

reduction in these losses could reasonably be expected, 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 encourage uniformity of

practice in gas installations and gas-company operation throughout

the country and such uniformity would contribute to efficiency and

economy in construction, operation, and maintenance. It is therefore desirable from every point of view that the code be completed

and issued as soon as is practicable, and the Bureau regrets exceedingly that there is no prospect of its being able to supply an adequate

staff for the work during the coming year. ELECTRICAL AND OTHER SERVICE STANDARDS.

Standards for Electric Service.

For several years the Bureau has been studying the question 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 Xo. 56. " Standards for Electric Service." and is now out of

print.

In addition to proposed State rules and specifications for accept- ance of types of meters, the circular contains three regulatory ordi- nances, suggested for cities of various sizes, descriptions oi 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 citv ordinances in manv instances.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 81

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 at least six new commissions

have been established, the functions of several old commissions have

been radically 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. The

material has been rearranged and much new matter is included. The

new edition will be an exhaustive summary of present-day electric- service regulation.

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 more than a year before the war 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 conferences held with managers and illuminating engineers.

The Bureau was receiving the hearty cooperation of municipalities

and lighting companies, but the war necessitated discontinuance of

the work.

During the year the work was again taken up in order to keep in

touch with street-lighting developments. New contracts have been

added to our files and the analysis of contracts continued. The manuscript for a circular on " Standards for Street-Lighting Service " is partly completed.

As in the case of Standards for Electric Service, the Bureau seeks,

while representing the public, to get the utilities' point of view as well ; the study of street lighting is being continued, but the result will not be published until full discussion and cooperation can be

again secured from public-utility corporations, technical societies,

municipalities and city managers and other interested parties.

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 in 1918. Field investigations were made in Ohio, Indiana,

and Illinois, heating plants visited, and conferences held with operating engineers. The cordial cooperation of the educational committee of the National District Heating Association has been of

much value.

A proposed set of rules for the regulation of central hot-water

heating plants was formulated and submitted to the Indiana commission and, after public hearing and criticism, was made the basis

for the rules formally adopted by that commission. The Bureau

has now nearly completed the manuscript of a circular on centralstation heating. This contains summaries of regulations, so far

10613—20 6
82 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

adopted by States, for both steam and hot-water systems, and proposed rules and regulations for commission adoption. Methods for

calculating " radiation," that is, customers' heating requirements,

engineering phases of contracts with customers, and brief suggested

contracts, are included in the study. It is hoped to complete this

circular during the next fiscal year with the cooperation of the

special committee of the National District Heating Association and

other associations and engineers interested in central-station heatingproblems.

Engineering Standardization.

The Department of Commerce is a member body in the American

Engineering Standards Committee, three representatives of the Bureau of Standards being members of the committee. At the re- quest of the standards committee the Bureau has prepared a complete list of engineering and technical organizations engaged in or

interested in engineering standardization. More than 150 societies

and organizations have cooperated in the preparation of this list, and many requests for copies have already been received from Government departments and engineering organizations. It will be

published early in the next fiscal year. TELEPHONY.

Studies of Systems of Telephony.

Considerable progress has been made in the detail study of tele- phone systems, work on which was begun two years ago as a neces- sary preliminary to an intelligent study of the broader subject of

telephone service. Particular attention has been given to the newer

types of cord circuits of the Kellogg Switchboard & Supply Co. and

the Stromberg-Carlson Electric Co. and to the machine-switching

systems of the Automatic Electric Co. To these might be added the

machine-switching system of the Western Electric Co., a preliminary

study of which was only begun in June. The need of labor-saving

equipment, never so apparent as at present, has focused attention on the above systems, all of which are designed, among other things,

to reduce operating labor.

In connection with our studies of circuit operation a departure

from the conventional type of schematic diagram has been made.

The new diagrams differ from the old in that associated contact

springs, though properly identified, are shown separated from their

actuating relay or magnet and are so placed as to emphasize their

operative relation to the circuits which they control or operate.

The component circuit elements are arranged so as to bring out as clearly as possible the mode and sequence of operation.

Circuit diagrams when so drawn may be considered as describing

in a particular type of shorthand full detail of circuit operation.

On this account it has been suggested that they be called " functionalizecl circuit diagrams."

Many circuits of manual, automatic, and semiautomatic switching

equipment of all the leading types and makes have been redrawn in

the manner described, thus making it possible to trace the circuit operation readily without the need of the peculiar type of memory re-
REPORT OF DIRECTOR OE BUREAU OF STANDARDS. 83

quired for equal familiarity with the corresponding conventional

schematics.

The diagrams have also proved of great value, in the preparation

of descriptions of circuit operations, which necessarily requires a clear

understanding of each successive step. They will also be of value in

connection with the diagnosis of " off-normal " and trouble conditions. Additional advantages of the " functionalizecl circuit diagrams " are found in connection with circuit analysis and with comparative studies of circuits of the same general type or of circuits

differing in minor details. Such diagrams should serve a very valuable purpose in connection

with the training of the many telephone employees required to carry

out the extensive automatic program announced by one of the largest

operating organizations.

Telephone Circular.

The tentative draft of a proposed publication on " Telephone service," to appear as a Bureau circular, was completed late in the fiscal year. As suggested by the title, emphasis has been put on the subject

of service, although a considerable part of the text has to do with

practice.

The object of the publication is to describe telephone service in

such a manner as to give the reader a fairly comprehensive understanding of what is involved in rendering telephone service and what

the elements of the service are which determine its grade. Its scope

is limited to a general introductory treatment of the subject suitable

for those who desire only a brief discussion. A more detailed and more technical presentation is reserved for subsequent publications.

In order that the circular may be as accurate as possible and hence

of maximum use when issued, mimeographed copies have been sent

to representatives of the Bell and larger independent telephone companies, to most State commissions, and to a number of- individuals for

comment and criticism before final revision for the printer.

Another proposed telephone circular, the rough draft of which is nearing completion, has to do with telephone transmission. This

paper, largely mathematical in character, takes up in order the subjects of the uniform line, composite lines, equivalent circuits, receiving-end impedance, fitting problems, artificial lines, and loading.

Laboratory Work.

Work in the telephone laboratory during the year was limited

almost wholly to testing. The recent addition of an oscillograph and

other apparatus, however, will permit the undertaking of additional

tests as well as certain research work planned some time ago. Tests made and under way include transmission and efficiency tests in connection with inquiries relating to repeating coils ; tests of the

loss in the efficiency of telephone receivers resulting from the use of

spool heads of conducting materials ; determinations of the electrical

and mechanical characteristics of radio receivers of various manufacturers, and the testing of dry cells for use in local battery tele- phone systems. The latter test, just begun, will of necessity extend

over the greater part of a year, since the test involves the determination of the variation with time of the resistance and electromotive

force of the cells under conditions simulating those met with in

service.
84 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

INVESTIGATION AND TESTING OF ELECTRIC BATTERIES.

New Testing Equipment.

Much new testing equipment has been put in operation during

the past year for the purpose of increasing the accuracy of the tests, the range of temperatures at which tests can be made, and to reduce

the labor involved in making the tests. The automatic control apparatus for dry-cell testing has been

completed. This apparatus carries on a number of different tests, as required by the different types of cells, simultaneously. It measures the periods of discharge and recuperation with great exactness. Only one man is now required to attend to this branch of the work,

where formerly two or three men were necessary for the same number of batteries under test. A brief description of this apparatus

has been prepared and is being published as Technologic Paper

No. 171. Apparatus has been installed for the testing of batteries at freez- ing temperatures and below. The capacity of all kinds of batteries

is reduced at low temperatures and it is important to determine the

operating characteristics of the different types of cells at low temperatures. Railroad signal cells for example are exposed to ex- tremely low temperatures in certain States during the winter; stor- age batteries used on industrial tractors are often exposed to low

temperatures; other types of storage batteries and dry cells are fre- quently subjected to low temperatures in airplanes. The equipment

which has been installed consists of a refrigerated room cooled by

a 2-horse power compressor that is automatically controlled by a thermostat in the room. The compressor runs intermittently and

maintains a constant temperature within the room. The room was

also designed for making the low temperature tests of caustic soda

batteries specified by the signal division of the American Railway

Association.

A Freas water thermostat has been installed for the determination of temperature coefficients of the various types of cells. This

is intended for use at temperatures slightly above and below room

temperature and it can be controlled to within 0.005° C. It is also used for fundamental measurements of electrochemistry.

A constant current discharge apparatus has been designed and in- stalled to maintain the discharge current of railway signal batteries when on test at a fixed value day and night without requiring

the attendance of the observer. This apparatus will maintain the current constant to within 1 per cent. A new test rack for storage batteries of the starting and lighting

type has been constructed. It is divided into six panels, each accommodating four batteries. Suitable resistances and switches have been provided for the charge or discharge of the batteries on test without

requiring the batteries to be moved or the connections changed. In

this wa}' the labor of making such a test has been greatly reduced.

A vibration board for testing storage batteries has been constructed. The object is to test the mechanical construction of the

batteries when subjected to severe vibration. A comparison of dif- ferent makes of batteries indicates that some are much better fitted for hard service conditions than other.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 85

Tests of Batteries.

Forty tests have been made for various Government departments on 217 batteries and three commercial tests on IT batteries. These

tests have been made for the Panama Canal, the Motor Transport

Corps, the Signal Corps, and the Ordnance Department of the War

Department. The batteries submitted for test have consisted of

various sizes and kinds of dry cells, flashlight batteries, storage batteries, and railway signal batteries. In addition to these tests a large

number of other tests of the performance of dry cells and storage

batteries have been made to obtain information required in writingspecifications and the preparation of circulars of information.

Dry Cells. Measurements of the conductivity of powdered manganese ore and

carbon have been continued and the study of the corrosion of zinc

by solutions used in dry cells has been extended to include the effect of many impurities which are likely to be present in manganese ore. The study of the effect of hydrogen ion concentration on the

potential of the manganese dioxide electrode was continued, and

Scientific Paper No. 364 on " The Eelation of the Voltage of Dry

Cells to the Hydrogen Ion Concentration " was published. This

paper shows the effect of acids and alkalis in dry cells and the reasons

that cells made of the same materials may differ in voltage.

An extended test has been made in various brands of dry cells to determine which are made with the artificial oxides and which with

the manganese ore. Cells made with the artificial oxide may give a large output when they are new but deteriorate rapidly. It is therefore important to determine the material from which the cells are made.

A chemical investigation of the best methods for determining the

presence of impurities in manganese ores has been carried out and the

results summarized in the form of a manual for laboratory use. Storage Batteries.

a. careful series of measurements on the structure of vehicle type

storage batteries of different manufacturers has been made. These

measurements include the weights and dimensions of all parts, and

the electrical breakdown, tensile strength, and elongation of the jar

material. These measurements yielded much valuable information

for the preparation of specifications.

The investigation of the cadium electrode mentioned in the pre- vious report was completed and published as Technologic Paper No.

146, entitled " The Cadmium Jilectrode for Storage Battery Testing."

The investigation of nitrates and nitrites in storage battery electro- lyte was completed and published as Technologic Paper No. 149,

" The Estimation of Nitrates and Nitrites in Battery Acid."

A large number of measurements have been made on the effect of

temperature on the capacity of storage batteries, including both the

acid and alikaline types. It is desirable that accurate information

as to the temperature corrections for the different types of batteries and at different rates of. discharge should be available to increase the accuracy of tests and decrease the time required to make them. A part of this work has been completed, but additional
86 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

investigations will be made in the low temperature room mentioned

above.

A circular, No. 92, on vehicle type batteries has been completed.

It is entitled " Care and Operation of Vehicle Type Batteries."

This circular was prepared at the request of the Construction Division of the War Department as a guide for the use of batteries of

this type in military depots. It is also intended to furnish information in answer to the questions contained in the manual of storage batteries issued by the committee on education and special training of

the War Department. It includes a discussion of the fundamental

principles of acid and alkaline storage batteries and gives typical

performance curves for each under varying conditions; it discusses

the capacity, the voltage, the resistance and the reactions of storage

batteries; it describes the methods of charging and of testing; and

it gives directions for the treatment of batteries in bad condition, for

the dismantling and repair of acid batteries, and for storage batteries not in use. The appendixes contain the War Department specifications for batteries of this type and for battery charging equipment.

Other appendixes give sample record forms for the proper operation

of batteries and an outline of the method for computing costs of

operation. The last appendix contains a glossary of more than 300

terms used in connection with storage batteries.

Specifications for starting and lighting batteries have been pre- pared, at the request of the Motor Transport Corps. The necessity

for these arises from the magnitude of the industry and the fact

that many batteries of inferior quality are now on the market. A

conference of representatives of the ' Motor Transport Corps, the .Bureau of Steam Engineering, Navy Department, the Society of

Automotive Engineers, the manufacturers, and the Bureau of Standardswas held at the Bureau to discuss them.

A'series of experiments on the loss of capacity of acid and alkaline

cells has been carried out, The object was to determine the rapidity

with which cells of different types lose their charge when standing

idle at a constant temperature. Another set of experiments has been

made to determine the efficiency of storage batteries, particularly

with reference to the rate at which the batteries are charged and

discharged.

The preparation of a circular on starting and lighting batteries

has been begun. This circular is intended to be brief, containing

only the information of greatest use to the owners and operators of

automobiles. It is to include a survey of the many sizes and kinds

of batteries now on the market, the specifications as prepared for the

Motor Transport Corps, and such data on the starting equipment as may be necessary for a proper understanding of the work the battery has to do. The number of different sizes and kinds of storage

batteries for this purpose at present on the market is unnecessarily

large, and the cost of production of these batteries could be considerably reduced by a proper standardization of the sizes with the elimination of a very large number which are little used.

The value of testing these batteries was emphasized by a recent

test of samples for a large order. Tests showed them deficient elec- trically and mechanically. They were found to contain second-hand

material.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 87

Railway Signal Batteries.

These batteries are of the copper-oxide-zinc type with an elec- trolyte of sodium hydroxide. They are used for operating signals

and similar equipment on many railway lines. During winter they

are often subjected to very low temperatures which impair their

performance. The Bureau has been called into consultation on this

subject by both the manufacturers and the signal division of the

American Railway Association. At the request of the latter, the

Bureau has sent a representative to the meetings of the signal di- vision and the battery committee. The Bureau has advised as to

specifications and tests for this type of battery. The performance of

these batteries in various typical installations of signals, crossing

bells, track switches, and interlocking^ has been studied. It is planned to make a very thorough investigation of these batteries

during the coming year, with the low-temperature apparatus described above.

Storage-Battery Nomenclature.

A representative of the Bureau was appointed a member of the

committee on storage batteries of the American Institute of Electrical Engineers. At their request, the Bureau has prepared the

definitions and nomenclature dealing with storage batteries. This

has been adopted by the standards committee, with slight modifications, and is to be included in the new standardization rules. Up to the present time the definitions of capacity, final voltage, and

standard temperature, etc., have differed widely among the various

manufacturers. It is important, therefore, that these rules should

set a standard with which the product of the various manufacturers

may be accurately compared and tested. Standard Cells. On January 1, 1911, the Clark standard cell was officially superseded by the Weston normal cell as the international standard of

electromotive force notwithstanding the fact that a number of investigators had held that the Clark cell was the more constant with

time. One of the chief reasons for this action was the frequent

failure of Clark cells through cracking of the amalgam limb about

the sealed-in terminal wire, and through the formation of gas in

the amalgam limb. The seriousness of these defects is shown by

the fact that 90 per cent of the Clark cells set up at the Bureau

in 1906 are tO-day useless because of one or both of these faults. Other investigators had similar experiences.

Experimental work has shown that cracking of the Clark cell can be prevented by employing as the negative or amalgam terminal

platinum wire subjected to the action of zinc amalgam before seal- ing it through the cell wall ; also that the effects of gas formation can be minimized through the use of only enough c^stals to insure

saturation at the highest temperature at which the cell is likety to be used. A more detailed account of this investigation will shortly

appear as Scientific Paper No. 390. In order that we might obtain a reliable intercomparison of the

standards of electromotive force of England, Japan, and the United

States, four selected Weston normal cells were sent to the National
88 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Physical Laboratory in England and a like number to the Electrotechnical Laboratory in Japan for comparison with the reference

cells of those countries. The cells were selected because of their

relative constancy over a long period and it is hoped that measure- ments to be made on their return to Washington will show them to have changed but little during their absence.

RADIOACTIVITY AND X.RAY MEASUREMENTS.

Gamma-Ray Measurements of Radium.

The amount of gamma-ray testing has increased so greatly and

so rapidly that all other work of the section has had to give way

to it. All investigations have been practically discontinued, requests

for X-ray and luminous material tests have not been encouraged,

and the feAY of these tests that were made have had to wait, often

for months, until a lull occurred in the gamma-ray work. During

the year over grams of radium and mesothorium were received

for test, while during the entire proceeding 5-J- years a little less than

32J grams were received. All indications point to a further in- crease in the demand for this Avork. The increase during the six and one-half years since routine testing

of radium was begun is shown in the following table

:

Year. Number

of tests. Milligrams

of radium. Year. Number

of tests. Milligrams

of radium.

1914 (half year) 2898

177 292

486 2,097

4.531 6,63S

1917-18 1,248

1,068 1,413

5,376

13,367

25, 278

1914-15 1918-19

1915-16 1919-20

1916-17

During the past year 1,240 gamma-ray measurements and 173

other tests have been performed; 23,259 milligrams of radium and

2,019 milligrams of mesothorium were submitted for test. This

material has a market value of over $2,600,000.

Seventy-nine preparations containing a total of 1,390 milligrams

of radium were certified for export; it was distributed as -shown in

the table below.

Country. Number of preparations.

Radium

milli- grams.Country. Number of preparations.

Radium

milli- grams.

Japan 22

119

6

62

7

4

517.

3

344.6 93.0

92.3

72.5

49.8 49.6

32.1

India 2

2

12

1

13

29.9

29.0

25.0

22.6

16.0 9.9

6.2

Philippines Spain

Brazil Panama

Cuba Porto Rico Canada South Africa Columbia Peru

Italy Holland

Australia

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
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 89

for the illumination of airplane dials of all kinds, of bomb sights,

compasses, gun sights, round 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 nothirig had been published concerning their

properties. In particular nothing was known regarding the effective

life of the material and but little information 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 Avar with Germanj-. 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

departments has largely supplanted the more orderly investigations

of the initial problems. Material bearing upon the latter has, however, been accumulated throughout this time and will be collated

with the earlier observations as soon as a sufficient staff can be provided to carry the routine testing and have some time free for more

constructive work.

During the past year even the tests of luminous materials have

been almost entirely crowded out by the large amount of work

required in the gamma-ray tests of radium. However, during the

first half of the year the Bureau cooperated with the Ordnance Department of the Army in the study of luminous targets and of

radium lamps for reading scales. Measurements were also made on

the brightness of a number of luminous gun sights both before and

after field use. Cordial relations with the manufacturers and civilian users of

these materials have been maintained. Many requests have been re- ceived from the latter for information and advice. These requests

have been complied with to the extent of our ability, but many

pertinent and important questions concerning these materials are

still unanswered, and can be answered only 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. X Rays.

As indicated above, the Bureau's X-ray investigations have for

the present been practically discontinued. During the year a few

tests of protective materials have been made, and for other sections

of the Bureau some radiographs of samples of metal and of wood

have been taken.

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 Bm-eau

began its study of these protective materials it was found that some

materials offered for protection were entirely Avorthless and few of
90 REPORT 0!F DIRECTOR OF BUREAU OF STANDARDS.

thern were as efficient as desired. The Bureau has been markedly

successful in securing an improvement in the quality of these materials, but the continuation of this improvement is dependent upon

the provision of additional support for the work.

Roentgenologists are thoroughly awake to the need for the study

and testing of all types of X-ray apparatus and materials and desire

the Bureau to take a commanding position in this work. The many

demands made upon the Bureau have, however, prevented it from

giving to the X-ray work the support that it . deserves and requires.

PUBLIC-UTILITY STANDARDS.

Public-Utility Investigations.

A large and important field of work, including more of engineering and field work than most of the electrical work so far described, is concerned with the various public utilities, particularly

electric light and power, gas, street railwa}T

, 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) safety 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 corre- spondence.

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 telephone 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 information on these questions and has been able to contribute materially

to the establishment of standards of quality in several of these services. Furthermore, it has promoted with marked success the practice

of settling disputed questions in this field on the basis of sound engineering and economic principles and of cooperation between interests rather than by legal controversy, and in so doing the Bureau has

attained an enviable position as an impartial mediator in such questions. Consequently, during the past three years, when abnormal conditions have given rise to man3T 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 the 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
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 91

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

where 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 engi- neers and inspectors large enough to enable them to take the initia- tive in every case and relieve the municipalities of all the responsibility. On the contrary, if the municipalities are active and enter- prising in their own behalf, and if the larger ones have well-equipped

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 municipalities will enjo}^

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 Avill conduce to fairness and a good understanding to have the subject studied further and to have specifications as definite and complete as possible made available for all branches

of public-utility service. Obviously, it will never be practicable for any State commission

or, city to handle these questions alone. Though they possess large

and able engineering staffs or employ specialists for each separate

problem, the question of what is good service or whether the service

in any given case is adequate, safe, and satisfactory can be settled only by reference to what is done under similar circumstances else- where 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,

it has clone enough to demonstrate the practicability and acceptability

of the method. The success and approval which the work has met

so far fully justify its greater development.

GENERAL CONDITION OF THE DIVISION.

During the war the demands for testing and research for the military departments were so numerous that the resources of the electrical

division, as of other parts of the Bureau, were largely devoted to such

service, and its experienced staff trained in experimental work was

an invaluable asset. Since the cessation of hostilities, however, the

situation of the division has grown increasingly difficult. The calls for service from the Government and from the industries have in- creased greatly, while the staff has become less capable of meeting

them, not merely because of the decrease in numbers made necessary

by the reduction of funds, but even more because of the continual loss of experienced and capable experts who have had to be replaced by
92 REPORT OF DIRECTOR OP BUREAU OF STANDARDS.

untrained ones. Of the 118 persons attached to the division on July 1,

1920, 90 had been here less than two years and 46 less than one year. Moreover, 24 were either serving temporarily or were known to have

plans for leaving in the near future. This situation has already

seriously affected the productivity of the division, especially in fundamental electrical investigation. Unless more adequate support can

be obtained, and a salary scale established which will enable the

Bureau to obtain capable scientific assistants and to retain them for

a reasonable time, it can not hope to maintain the high standing in

this field which has been won by years of labor. A staff of trained

investigators can not be built up in a month or a year, and if the

present situation is not remedied soon the damage to the Bureau

through loss of its experienced men will be well-nigh irreparable.

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 requirements; standardization of

calorimeters; production and distribution of standard beat and temperature samples;

industrial applications of heat and temperature measurements ; determination of funda- mental engineering data involving thermal constants; determination of the fire-resistive properties of structural materials; investigations relating to automotive power plants,

fuels, and lubricants. THERMOMETRY.

This section is concerned with researches on the standard scale of

temperature and thermometric fixed points from the lowest attainable temperature up to about 500° C. : maintenance of working standards within the above range ; methods of standardizing temperaturemeasuring instruments, such as liquid in glass thermometers, vaporpressure thermometers, resistance thermometers, thermocouples; the

testing and certification of temperature measuring instruments; and

methods of measuring temperatures.

Clinical Thermometers.

Inasmuch as a large proportion' of the clinical thermometers sold to the public were believed to be unreliable, a conference representing

the several governmental agencies concerned and a number of the

manufacturers was held at the Bureau to consider means for improving existing conditions. There was little difficulty in arriving at a

decision as to the accuracy and reliability requirements necessary to protect the public and which at the same time would present no unreasonable manufacturing difficulties. With a view to obtaining more reliable information as to the conditions existing in the trade, the Bureau, at the request of the manufacturers, undertook to secure representative samples of clinical ther- mometers on sale or in use in hospitals. A considerable number of

thermometers were obtained for this test, the results of which will be

available during the early months of the next fiscal year. Standard Temperature Scale.

The standard scale of temperature adopted by the Bureau as its working standard scale in the interval —40° to -4-450° C. is that

defined by the resistance thermometer of pure platinum standardized

at the temperature of melting ice (0°) , of steam condensing at normal
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 93

atmospheric pressure (100°), and at the temperature of the vapor of

sulphur boiling at normal atmospheric pressure (414.6°). The

working scale previously used in the interval to 100° C. was the in- ternational hydrogen scale as distributed by the International Bureau

of Weights and Measures through the intermediary of mercury in

glass (verre dur) thermometers. To ascertain the order of agree- ment of these two scales, a series of comparisons was made between a number of verre dur standard thermometers and several platinum

resistance thermometers. The agreement between the mean hydrogen

scale defined by all the verre dur thermometers included in these in- tercomparisons and the scale defined by the platinum resistance thermometers Avas found to be practically within the limits of accuracy

with which the former can be used (about 0.005°). The only indication of a systematic difference between the two scales was found in

the interval to 30°, where the indications of the resistance thermometers Avere uniformlv higher, attaining an average difference of

0.005° from 10 to 25°. Industrial Thermometers.

An investigation of industrial thermometers under various conditions of use was undei'taken for the purpose of obtaining data

which would be useful in specifying the methods for testing and

calibrating these instruments. A number of representative types of

industrial thermometers were loaned by the manufacturers for this

investigation. The results so far obtained may be summarized in

the statement that for most of the types in common use, the indications, for a given temperature of the medium the temperature of

Avhich is to be measured with the thermometer, are very largely in- fluenced by the character of the medium, its rate of circulation, and

the character of the mounting of the thermometer. Thus the indications of a certain thermometer were found to differ by over 100° F. when it was used in rapidly circulating oil and air, respectively, both at the same temperature. Therefore many types of industrial thermometers can not be used to measure true temperatures unless calibrated

under conditions of use. although they may still be useful as indicating instruments showing changes in temperature or for reproducing

identical temperature conditions from day to day. Obviously, if one thermometer is replaced by another of different type, its indications

may be different for the same true temperature. When opportunity

affords, the tests will be extended to the measurement of the temperatures in saturated and superheated steam. Although superficially the

two cases are A*ery similar, it seems probable that differences Avill be found quite as great as between measurements in circulating oil and air, respectively. This is due to the fact that saturated steam

supplies heat very rapidly to colder objects by condensing upon them,

while superheated steam has in this respect the properties of a gas. The results so far obtained will be included in a report which will

be submitted to manufacturers and others interested.

Melting Points of Greases.

This section was requested by the oil committee of the Bureau

to investigate various methods used in determining the melting points

of lubricating greases and to select a standard method for making

the determination.
94 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Methods recommended in the literature on this subject and those- used by commercial firms were investigated. A method differing in

slight details only from that known as " Pohl's " was finally adopted

after careful consideration of the others investigated. This method

may be briefly described as follows: A thin coating of grease is applied to the bulb of a thermometer, the general construction of

which is specified. This thermometer is then suspended in a test tube immersed in a water bath, or for higher temperatures in an oil bath. The temperature at which the first drop of grease flows from

the bulb is called the melting point of the grease. The method was

applied to a large number of greases and the results indicated that an accuracy of from 1° to 2° C. could be obtained.

Specifications for Standard Chemical Thermometers.

At the request of a committee from the American Chemical Society, specifications were drawn up for three proposed standard

types of chemical thermometers. The intention of the committee

is to provide a small number of chemical thermometers of standard

design which can be used for a very large number of measurements.

The specifications for these thermometers when approved by the

committee will be submitted to the manufacturers of thermometers.

It is thus hoped that a uniform type of thermometer can be secured

at a reasonable price, and that the agreements of results obtained in

different laboratories will be much more satisfactory if one type of

thermometer is used for a given measurement.

Testing Equipment.

The greater part of the testing equipment of the thermometric

laboratories was designed primarily for work of high precision. The

increase in the amount of testing of thermometers of ordinary grade

has made it necessary to supplement this equipment with comparators designed to permit more rapid testing while insuring the re- quired accuracy. With this end in view, an electrically heated water- bath comparator for testing in the interval 10 to 90° C. and an

electrically heated oil-bath comparator for testing in the interval

100 to 325° C. were designed and the construction nearly completed.

The comparators will accommodate as many as 24 thermometers.

A portable electrically heated steam point apparatus was also designed and constructed for use in the thermometric laboratories.

HIGH TEMPERATURES.

This work includes researches on the standard scale of temperature

and thermometric 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
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 95

radiation in gases and vapors, etc. ; industrial pyrometry and the

measurement of the temperatures in industrial processes; and the

annealing of glass.

Industrial Pyrometry.

At the symposium on pyrometry held at Chicago in .September

under the auspices of the pyrometer committee of the National Research Council nine papers were presented by members of this section. Some of the work in industrial pyrometry was reported upon

at this time. The papers which have been published this year embrace treatises on thermoelectric pyrometry, optical and radiation

pyrometry, recording pyrometry, high-temperature control, standard scale of temperature, melting points of refractory materials,

and pyrometry in rotary Portland cement kilns. A book of about 350 pages, 160 illustrations, tables, etc., on the

methods of pyrometric practice has been prepared and will appear

as a technologic paper of this Bureau. All the methods of pyrometry

in present-day use are described. Methods found desirable for the

calibration of all types of pyrometers are presented in detail. The

use and care of instruments are considered, and attention is given

to the modern extensive installations of pyrometric equipment, wiring

diagrams, etc., suitable for large plants. One section of the book is devoted to pyrometric methods and installations for specific industrial processes. Standard Samples for Thermometric Fixed Points.

The Bureau issues samples of various materials, the melting or

freezing points of which have been determined Avith high precision.

By this means the standard temperature scale of the Bureau may

be distributed to the various technical laboratories. The supply

of several metals was exhausted last year but has now been re- plenished by 1 ton of lead, 1 ton of copper, and several hundred

pounds of zinc and tin. The melting points of these metals have

been determined during the present year and the material has been

divided into about 3,000 standard samples.

Heat Treatment of Glass.

The investigation of suitable methods for the annealing of glass

has been continued. Glass for use in optical instruments as lenses,

etc., must be so annealed as to remove all stresses producing warping of the surfaces and optical inhomogeneity. The strain tending

to cause changes in the volume of thermometer glass must be re- moved and the annealing of ordinary glassware should be so carried out as to reduce to a minimum all strains tending to cause breakage.

The annealing temperature and process of cooling various glasses

have been investigated in detail. Two papers have been published

and others are in preparation.

A number of manufacturers have submitted different kinds of

glass for test in order to obtain directions for annealing. Several

extensive reports of a confidential character have been prepared for

various Government bureaus and manufacturers.

Considerable work has been completed on the " tempering " of

glass. In certain processes of heat treatment whereby strain of a.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

definite character is introduced a fairly nonbreakable glass may be

produced. Such glass has been employed for goggles, etc. Investigations in Electronics.

When electrons having velocities in general less than 300,000,000

centimeters per second (about 1,900 miles per second—a small

velocity for electrons) collide with molecules of gas or vapor the

collision is usually nearly elastic. That is, the electron after the

impact has the same velocity as before the impact. There are cer- tain critical velocities in this range, however, for which the collision

is inelastic and the molecule absorbs a definite amount of the

kinetic energy of the electron. One general type of inelastic col- lision results in a rearrangement of the electrons forming the molecule. Another type causes the ejection of an electron from the

molecule, leaving the molecule positively charged. Still other types

of collision result in a dissociation of the molecule into charged

atoms. One result of such collisions is the production of light.

Hence a study of the types of collision occurring in various gases

and vapors is of importance from the standpoint of illumination

and may lead to a more efficient form of electric light. Eesearch

of the above character has already found many commercial applications in technical fields, for example rectifiers and arc lamps.

Such investigations are now being carried on in many laboratories

in this country and abroad in order to advance our knowledge of

the ultimate structure of matter. The work on metallic vapors reported last year has been con- tinued and extended to nonmetallic vapors and gases, including the

vapors of several compounds. Four papers have been published

during the year and two others are now in press. These include

measurements of the ionization and resonance potentials of lead,

calcium, nitrogen, oxygen, hydrogen, phosphorus, sulphur, and

iodine, a critical investigation of the theory and operation of arcs

in caesium vapor, determination of several fundamental physical

constants, and a description of a new method of measuring photographic density of spectral lines. HEAT MEASUREMENTS.

Measurements are made in this section over a wide range of tern- peratures 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. Work is also done on the development of calorimetric apparatus and methods ; and on methods for temperature control, pressure ! measurements, measurement of heat transmission, etc. Practically all of the research work of this section during the

year has been devoted to the determination of those fundamental

physical constants of materials which find application in refrigeration

engineering.

Vapor Pressure of Ammonia.

The results of the numerous measurements of the vapor pressure

of ammonia referred to in the previous report have been completed
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 97

and prepared for publication and have been published. (See list of

publications.)

Vapor Pressure of Carbon Dioxide.

Numerous measurements have been made during the year of the

vapor pressure of liquid carbon dioxide in the range between the

triple point and the critical temperature, using methods and equipment similar to those used in the work on ammonia. The completion

of this research has been delayed by unexpected phenomena requiring

further careful investigation.

Specific Volume of Liquid Ammonia.

Measurements have been made at various times during the past

few years of the density of samples of liquid ammonia of high

purity, prepared by several methods, using calibrated glass pic- nometers. Determinations were made throughout the temperature

interval —78 to -f-100° C, and the accuracy obtained was of the

order of a few parts in 10,000. During the present year the experimental work was completed, the computation finished, and the re- sults were prepared for publication.

Specific Heat of Sodium Chloride Solutions.

This work, which was completed several years ago, was not published due to the fact that the author left the service of the Bureau before the material had been prepared for publication. The results of

this investigation have now been worked up and made ready for printing. The work includes determinations of the specific heats of a number of solutions of various densities, at temperatures between their

freezing points and +20° C. The data furnished by this investigation, taken in connection with those described in the following paragraph will be used in the preparation of tables of the properties of

brine, for the use of refrigerating engineers.

Density and Thermal Expansion of Sodium Chloride Solutions.

The experimental work relating to the density and thermal ex- pansion of sodium chloride solutions in the temperature interval

between their freezing points and -f~50° C. has been completed and

the results prepared for publication in cooperation with the divisons

of chemistry and of weights and measures.

Specific Heat of Gases.

Development of a flow calorimeter to measure specific heat of

gases has been actively pursued.

The chief progress has been in the direction of perfecting technique

of construction such as to permit refinement of the design at points

where the preliminary experiments have shown the need for improvement. The aim is to produce an instrument which will permit accurate measurements of the heat capacity of a gas at temperatures from —80 to -(-150° C. at any pressure up to 1,500 pounds per square inch.

Because this heat capacity is small for a given volume of gas, it is essential that the construction be at the same time delicate and ro- bust—delicate in the sense of small mass of material used so that

the physical magnitude observed be not overburdened by bulk of

10613—20——

7
98 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

apparatus, and robust in the ability to withstand the stress due to the pressure. The construction has progressed to the point of the final assembling

of the instrument. The next step is to put it in operation and to construct and set up numerous accessories, such as thermo-regulated

baths, evaporators, condensors, pressure regulator, flow gauges, pres- sure gauges, and various electrical measuring equipment.

Testing of Thermal Insulators.

Testing of thermal insulators has been carried on at the Bureau

for a number of years, and results of tests of a large number of materials used for insulation have been published. There has been a demand from refrigerating engineers for the standardization of

tests of insulating materials along the lines which have been developed by the Bureau in order to eliminate the confusion resulting

from the use of widely different methods of testing. Specifications

for a standardized equipment have been prepared and submitted to the American Society of Refrigerating Engineers.

Preparation of Pure Materials.

In cooperation with the chemistry division supplies of pure ammonia, ethyl chloride, and carbon dioxide were prepared. The am- monia and carbon dioxide after drying were further purified by

fractional distillations. The ethyl chloride was prepared and further

purified by fractional distillations. These materials were intended

for work on the determination of those physical properties which are of importance in refrigeration engineering.

THERMODYNAMICS.

With the reorganization of the division of engineering physics some of the functions (including work in pure and applied thermodynamics) previously cared for by this section were transferred

to that division. The physicist formerly in charge of this section was transferred at the time of reorganization. When circumstances

permit, the work will be resumed.

CRYOGENIC LABORATORY (LOW TEMPERATURES).

This work is concerned with the production of low temperatures

down to those of liquid hydrogen (ultimately liquid helium), preparation and storage of pure gases, development of methods of producing and maintaining low temperatures, liquefaction and separation of gases at low temperature, and special tests requiring the

facilities of the low-temperature plant.

Operation of Plant.

The liquid-air plant has been operated about once 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 number of other institutions in Washington and the vicinity.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 99

The carbon-dioxide, low-temperature system was operated almost

daily to provide cooling for thermometer comparators, the investigation of refrigeration constants, the testing of aviation instruments,

and other purposes.

Generators for acetylene, hydrogen, and oxygen were maintained

in operation, and these gases were supplied to other laboratories.

Hydrogen Liquefier.

A hydrogen liquefier designed se'veral years ago was completed

and installed during the year. It is believed that this equipment

will be capable of producing sufficient quantities of liquid hydrogen

for present needs, and its operation will provide a basis for the

design of permanent equipment for the production of liquid hydrogen in considerable quantity.

Liquid Oxygen for Use by Aviators.

Work is under way on a container for liquid oxygen to be used in

high altitude airplane flights to supply oxygen for respiration.

FIRE-RESISTIVE PROPERTIES OF STRUCTURAL MATERIALS.

In this section the standardization of fire tests is investigated ; fire tests of structural materials and structures are carried on, as well

as investigations to develop engineering data relative to the fire- resistive features of building construction; tests of fire-retarding

devices ; and investigations of building codes and fire codes. 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

and safety of various types of building material and construction

when exposed to different conditions met with in fires. Fire Tests of Building Columns.

The results of the series of fire tests of building columns jointly

conducted by the Associated Factory Mutual Fire Insurance Cos.,

the National Board of Fire Underwriters, and the Bureau of Standards have been prepared for publication and will be issued as a

joint report by the cooperating organizations, and also as a number

in the Bureau's technologic series, both of which will probably be

available in printed form at an early date. The investigation comprises fire tests of 106 building columns representative of current building practice in material, design, and methods of protection.

General notes on the purpose, scope, and methods of testing employed have been given in previous reports, with summary of some

important test results. The reduction of the large mass of experimental data into forms suitable for publication was accomplished

during the progress of the tests and in the period immediately fol- lowing their completion. General comparative diagrams and tabulations were subsequently prepared and bases of interpretation established to give the test results the nearest possible approach to direct

practical application. The forthcoming publication will be of about

400 pages, nearly one-half of which consists of illustrations, dia-
100 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

grams, and general tabulations, an effort having been made to secur

as much brevity as was consistent with adequate presentation.

Strength of Materials at High Temperatures.

Brief description of an apparatus for determining the compressive

strength and elastic properties of materials as affected by heat, and

notes on results obtained in a preliminary series on structural steel, have been given in previous reports. During the year further tests of steel have been made and some preliminary work done on concrete and timber. The tests of concrete indicate that at temperatures

resulting from fire exposure of structural members the expansion

of concrete under load is much lower than at normal temperature,

a fact that has a decided influence on the physical behavior of composite members of concrete and steel or cast iron when exposed to fire. The tests of timber, which have as yet been made on only one

species, show large reductions in strength at temperatures near 100°

C, although not such as to cause failure under working loads. Beyond 150° C. further decrease in strength was marked, failure underworking loads being imminent before 200° C. was reached. On cool- ing the timber regained a large proportion of its original strength.

Pyrometer Lag.

The importance of determining the characteristics of indication of

pyrometers when used for measuring rapidly rising and falling temperatures, as is incident with fire tests of structural members, led to an investigation which has been completed as far as it concerns the

pyrometer type, used in the jointly conducted fire tests of building

columns. Statement of essential results attained is given in the

report of the column investigation noted above. The effects due to the heat insulating and absorbing properties of the mounting and

couple wires were found to be very large near the beginning of the

test, and caused the pyrometer indications to be too low by several

hundred degrees centigrade. The differences became rapidly smaller

and after one-half hour immersion in the furnace chamber the error due to this cause was quite small.

Another source of error investigated was that clue to radiant heat

interchange between the pyrometer and the inclosing walls, which

latter, in a furnace where the source of heat is combustion within

the chamber, are at lower temperature than the furnace gases. For

the type of furnace and size of pyrometer used the error was found to be about 150° C. near the beginning of the test, with gradual decrease

to less than 50° C. at the end of an eight-hour run. The investigation discloses the difficulties involved in temperature

measurements under the given conditions and the need of standard

methods if comparable results are to be obtained with different fur- naces and pyrometer equipments.

Fire Tests of Concrete Columns.

The experimental work relating to the fire-resistive properties of concrete columns, which has been under way for several years at the

Pittsburgh laboratories of the Bureau, was completed during the

year.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 101

A brief summary of the nature of these tests and some of the more

general conclusions have been given in previous reports.

The investigation included a comparison of the fire resistance of

four types of columns made from the same aggregate, a comparison

of the fire resistance of similar columns made from seven types of

aggregates, and a comparison of the effectiA- eness of several methods

of providing special protection for columns which without such protection did not give favorable results in the fire test. In the entire investigation 90 column tests have been made, of

which 62 were fire tests, 16 were compression tests of columns which

had not been fire tested, and 12 were compression tests of columns

which had been fire tested, but which after four hours of fire test did not fail, while hot, under the maximum load obtainable with

the furnace-loading equipment. Of these 90 tests 28 have been

made since June 30, 1919. The results obtained indicate that concretes may be divided, with

respect to their fire-resistive properties, into two general classes,

those which show a tendency to spall vrhen exposed to fire and those

which do not. The tendency to spall was observed in concrete made

from aggregates consisting largely of quartz or granite, and such

concretes made the poorer showing in the fire tests. Full details of

results relating to the behavior of the different types of columns,

aggregates, and protective devices which have been tested were given

in progress reports made to the American Concrete Institute and

published in its proceedings for 1918, 1919, and 1920. A complete

report of the investigation is to be published as a technologic paper

by the Bureau.

Fire-Resistive Properties of Wall Plasters.

In most dwelling houses and in a very large proportion of the

buildings of other types tlie interior surfaces are covered with

plaster of one kind or another. Many exterior walls are covered with

plaster, under the name of stucco. The materials used in plastering

being, for the most part incombustible, wall plasters, both interior

and exterior, afford some protection against fire and because of the

extent of their use it is of importance to have definite information

as to the amount or degree of fire protection afforded, in different

kinds of strictures by various plasters. A considerable amount of

information- of this character has been gained by a series of fire tests of specimens made from plasters of many compositions.

Plaster specimens were made 26 inches square and either 1 or 2

inches thick, with metal lath embedded next to one surface. A small

gas furnace was built, capable of accommodating four test speci- mens. The furnace was heated in accordance with the standard timetemperature curve for fire tests, and measurements were made of the

heat transmitted through and of the deformation of the plasters.

The materials tested included a large number of mixtures, not only

those in common use but other combinations of materials which

appeared to be worthy of consideration, particularly in view of the

possibility of usefulness for the protection of steel and of loadbearing concrete in fire-resistive construction. This usefulness depends on a number of properties, including heat insulating efficiency
102 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

and ability to remain in place when exposed to heat. Both of the

above tests were designed to give information bearing on these properties. In addition to the materials ordinarily used in commercial plastering, mixtures containing asbestos and others containing kieselguhr were included.

It was found that differences in rate of heat transmission through

different plastering mixtures containing large proportions of sand

are not great enough to be of importance in the fire resistance of

the plasters. Gypsum wood fibered plaster, plaster containing as- bestos and mixtures containing kieselguhr showed superior insulating properties.

All highly sanded mixtures such as are in common use in building

operations showed rapid expansion when exposed to fire. Specimens

made from mixtures of gypsum plaster and sand or of gypsum, lime,

and sand, in which the sand content was low, showed initial expansion followed by shrinkage. No combination of these materials was

found which would bear exposure to heat, under the fire-test conditions, without deformation. One of the most promising mixtures,

in point of deformation, and one which also showed fair heatinsulating properties was a mixture of Portland cement and crushed

cinders, the latter being used to take the place of sand. Specimens

made from this mixture showed a small initial expansion followed by

a slight shrinkage. The performance of this mixture indicates that

it would be greatly superior to mixtures of Portland cement and

sand as far as staying in place under fire conditions is concerned. It

is probable that it would also resist a hose stream after exposure to

fire.This investigation is to be continued to include tests on large speci- mens in the Bureau's panel-testing furnace, which has been described

in previous reports.

Temperatures Attained by Protected Steel in Floor and Roof Slabs

Under Fire Conditions.

The small furnace used in fire tests of plasters was also used in

tests made to determine the temperatures attained by the steel in

gypsum roof slabs in which the steel was protected by three- fourths

inch of the material, and also in similar slabs with an additional

protection of three-fourths inch of wood-fibered plaster. Similar

tests were made with sections of concrete floor slabs with the steel reinforcing rods located at depths of f, 1, and 1| inches from the

surface representing the bottom of the floor slab which was to be

exposed to the heat in the fire test. The aggregates used included

blast-furnace slag, gravel, bituminous cinder, and limestone. The

standard time-temperature curve for the fire test was followed, the

tests being of four hours' duration. Temperatures were measured

by means of thermocouples attached to the steel. As was shown by tests reported last year, structural steel may be

expected to fail, under its working load, at temperatures below

575° C. Steel in the gypsum roof slabs protected by three-fourths

inch of material attained this temperature in approximately 1 hour

50 minutes. In roof slabs which had the additional protection of

three-fourths inch of wood-fiberecl plaster, making 1| inches in all
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 103

protecting the steel, the temperature of 575° C. had not been reached

at the end of the four-hour fire test. In the fire tests of concrete floor slab sections, the rate of heat

transmission to the steel did not vary greatly with the different kinds

of aggregates, though there was a persistent difference in favor of

the limestone aggregate in this respect.

In general, it may be said that steel at a depth of one-half inch

reached the 575° C. point in less than one and one-half hours; at a depth of 1 inch this temperature was reached in less than two and

one-half hours, except in limestone concrete specimens ; at a depth of

1-J- inches the same temperature was reached within three and onehalf hours in most cases. These results show that the thickness of concrete protection ordinarily provided for steel in floor slabs, beams, and girders is inadequate for its proper protection during severe fires of long duration, even assuming that the protective concrete were to remain in place

throughout the fire. A technologic paper will be published covering

this series of tests. AUTOMOTIVE POWER PLANTS, FUELS, AND LUBRICANTS.

Investigation of the fundamental, scientific, and technical problems

related to the design and operation of internal-combustion engines

and accessories, and the qualities and characteristics of fuels, lubricants, etc., for use in such engines are conducted by this section.

An increasing demand on the part of the automotive industry

for research in fundamental problems of this industry has developed,

as anticipated, during the year, but a looked-for decrease in the

demands on the section for researches in the field of aeronautics has

not developed. In fact, the demands along some of these lines have

increased. As a result, the section has been called. upon to cover

a rather wide field of activities, including all classes of automotive

power plants.

Altitude Laboratory.

When an aircraft engine is flown at high altitudes the power of the

engine is very much less than at ground level. Other features, such

as air temperatures, oil temperatures, load, etc., differ radically from

ground-level conditions.

The Altitude Laboratory, built especially for the study of- these

problems, has been used for studying the performance of the Liberty

" 12 " engine and the Hispano-Suiza 300-horsepower engine for the

Air Service. Engineering Division, Dayton. Reports describing

this work have been prepared for publication. A comprehensive

research covering all features of performance of the Hispano-Suiza

180-horsepower engine, with special reference to means for increasing

the power and fuel economy at high altitudes, was also undertaken.

Two general methods are aA^ailable for improving the power and

fuel economy of aircraft engines at high altitudes; these are by

supercharging and by supercompression. The former involves the

addition of some type of blower or compressor to increase the

pressure of the air taken into the cylinder, while the latter makes

necessary an increase in the compression ratio, i. e., the extent to
104 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

which the combustible charge is compressed before firing. Its application requires an accurate knowledge of the effect of changes in

compression on power and economy. This information is made

available b}' the investigation referred to above.

Minor problems completed include, (a) tests of exhaust valves

of special alloys; (b) a comprehensive general analysis of the vari- ous factors in engine performance at high altitudes.

Lubrication of Automotive Engines.

The development of a lubrication laboratory with special refer- ence to study of lubrication problems in automotive engines was

begun in 1918, hence much of the time has been devoted so far to the development of apparatus and methods.

A series of tests were run in a typical aeronautic engine to determine, if possible, any difference in lubricating value of oils from

different classes of crudes. The results showed no significant differ- ences between property refined oils from different sources, provided

the oils are chosen with equal care to meet the conditions of

operation.

A series of routine laboratory tests was run on samples of all trade-marked oils sold on the market and which could be secured

by the Bureau. The results will serve as a guide to purchasers of

oil and it is hoped will be of much value when published in the near

future.

A new method of distillation has been perfected for the analysis

of lubrication oils, which has proved to be of great value. By the

use of superheated steam at very low pressures, in a special still, it is possible to fractionate ordinary lubricating oils and determine their

composition with, in most cases, a negligible amount of decomposition. This process gives promise of important applications in the

refining of oils. Other problems which have been undertaken are (a) the relative

effects on different classes of oils of dilution by fuels escaping into

the crank cases of engines, (b) the extent to which fuel vapors are

dissolved in different classes of oils. No significant differences betwen oils in these respects were found.

The tendency of oils to form so-called carbon deposits in engine

cylinders has been investigated to some extent during the year. Further investigation of the oxidation test and the demulsibility

test developed by the Bureau has been made in this connection. Tests of 25 commercial brands of automobile oils were carried out

in cooperation with one of the large automobile manufacturers. A

number of special types of automobile oils were also tested for the

inventions section of the War Department.

Cooling Problems.

The general features of a very comprehensive investigation of

the problems involved in the cooling of circulating water for air- craft engines by means of so-called radiators were completed last year. This work has been followed during the current year by (a)

tests of a considerable number of new radiator designs for the Air

Service of the Army; (b) detailed investigations of the conditions

of pressure, temperature, and velocity occuring within the air spaces

of typical radiators and of experimental air tubes; (c) mathematical
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 105

and limited experimental application of the results previously obtained to the cooling of " air-cooled " engine cylinders.

A study has been made of the radiator requirements of an engine

when operating at altitudes with a supercharger as mentioned under

"Altitude laboratory."

A series of experiments were run for the Navy Department to determine the practicability of a method for recovering water,from

the exhaust gases of engines used in airships. A number of experiments were carried out to determine the pressure drop and heat transfer in a special exhaust pipe section made up for this investigation.

The recovery of water is required for helium airships as otherwise

the reduction in total weight by consumption of fuel would require

the loss of gas. Helium is too expensive and the available supply too small to permit its general use without some such device for its conservation.

The results of the investigation of cooling problems have been of

special service to the Engineering Division, Air Service, in the design of cooling systems for new types of airplanes. The latest cool- ing devices promise important improvements in efficiency.

Five reports covering work during the current year on cooling

problems have been completed and will be published in the Fifth

Annual Report of the National Advisory Committee for Aeronautics,

as noted under the heading " Publications."

Two papers dealing with cooling problems were published in technical journals.

Carburetion.

The laboratory for research on carbureter problems has been used

for tests of a number of carbureters, including the following : White

Co., Browne, Mitler, German Zenith (from German motor truck)

U. & J. A mathematical analysis of the laws of flow involved in one method

of compensating for the effects of change in air density at altitude has

been completed. Similar analyses of other methods are required.

The fuel economy and power of an internal combustion engine depend upon the condition of the mixture as regards temperature,

vaporization of fuel, degree of mixing, etc. An investigation of this

problem has been in progress. Essential to this investigation is a knowledge of the vapor pres- sures and vapor volumes of the customary fuels. Apparatus for

measuring these quantities has been in use for some time and results have been obtained on a number of fuels. The carburetion research has been undertaken mainly at the in- stance of the Air Service and of the National Advisory Committee

for Aeronautics, but some features of it are of equal interest to the

manufacturers and users of all types of automotive appliances.

Ignition.

Ignition problems have been handled jointly by this and the elec- trical division of the Bureau and a portion of the work is described on page 56 of this report. A number of magnetos and one battery

ignition system have been tested as to their characteristics and per- formance.
106 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

The effects of various factors on the voltage required to produce

a spark at the terminals of various types of spark plugs under operating conditions have been determined. The results of this work are of special importance in providing for reliable ignition on engines

operating at high altitudes with a supercharger.

A special research was undertaken to determine definitely the cause of occasional failures of ignition in aircraft engines apparently due

to faulty spark plugs. The results were to demonstrate conclusively

that early ignition of the cylinder charge due to overheated spark

plug terminal was the cause. Types of construction which tend to aggravate or to prevent this effect were determined. The cylinder

pressures resulting from such preignition were also shown to be some three times normal pressures and to constitute an enormous

accidental overload on the engine parts.

Phenomena of Combustion.

A knowledge of the phenomena which accompany the burning of

fuel in engine cylinders is of importance in the design and improvement of such engines. A study of some features of the problem

has been in progress for several years. A method previously devised of measuring the rate of progress

of the explosion flame in an engine cylinder has been applied to a determination of the effects of spark timing, fuel-air ratio, and turbulence on the flame speed. Direct visual observation of the flame in a cylinder has been made possible by a special type of sight plug or widow which will withstand explosion pressures. Rates of combustion in mixtures of air and gas at ordinary pres- sures have been measured by direct observation and photographic

records of the shape of free gas flames under definite conditions. The

results obtained by this method supplement those by direct observation.

A paper entitled "A Study of the Velocity of Flame Propagation

in the Cylinders of Aircraft Engines " was prepared for publication

in the technical press. Fuels.

The situation of the country as regards motor fuels is such as to demand greater efficiency and economy in their use. To meet this

situation a comprehensive program of research has been laid out

in cooperation with the Bureau of Mines and the Society of Automotive Engineers to make available to designers, manufacturers, and

users of automotive apparatus such information as will lead to better

utilization of motor fuels. As a part of this program a special research was undertaken to determine the effect of intake manifold temperature and mode of

heating on fuel economy and acceleration of typical automobile en- gines burning commercial gasoline. Eesults of this research have

been communicated to the Society of Automotive Engineers.

A considerable number of special motor fuels have been tested in

engine operation for other departments of the Government and for

general information.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 107

Dynamometer Laboratory.

A laboratory building for the use of the automotive power plants

section was finished last year, and the equipping of this building has now been substantially completed.

The general equipment consists of two vacuum chambers for the

testing of aircraft engines under altitude conditions, with their ac- companying dynamometers, pumps, refrigerating machines, etc. ; one

extra 300-horsepower dynamometer for use with aircraft and other

large engines ; three smaller dynamometers, one 150, one 125, and

one 75 horsepower, with their accessories for general engine research

;

a drum dynamometer (not yet completed) for performance tests of

automobiles and trucks; as well as an adequate supply of minor

equipment, instruments, tools, etc., for the class of work to be undertaken.

Special equipment for work in cooperation with the Motor Transport Corps and the .Society of Automotive Engineers has been completed. This consists of the following units

:

1. Equipment for tests of the different designs of power trans- mitting systems in rear axles for trucks.

2. Equipment for tests of brake-lining materials with a view to standardizing such tests.

3. Equipment for tests of radiator fan belts. Miscellaneous.

Several special measuring instruments have been designed and

constructed for the use of the laboratory. These include (a) a cylinder pressure indicator which has been under development for some

time and has proved to be an unexpectedly accurate and convenient

instrument, and is now in demand by the automotive industry; (b) a relief valve type of maximum pressure indicator which has proved

successful; (<?) an instrument for conveniently measuring the clear- ance space in engine cylinders. This instrument has proved of in- terest to other industries, such as the building of refrigeration machinery, air compressor's, etc., and is likely to piwe of considerable

value.

A large number of miscellaneous tests have been made during the

year for various departments of the Government, including the

Inventions Board of the General Staff of the Army, the Motor Transport Corps, Signal Corps, Navy Department, etc. Several different types of small gasoline engine, such as are used

for electric generator sets, were tested for performance and reliabil- ity for the Signal Corps.

The following tests of a general nature were carried out during the current year : Compression test of Motor No. 102 for the Willys Corporation, test of a Turner-Long automatic observer for the Air Service, test of a Hoag manifold superheater, and test of a Dempsey valve

cycle.

A number of investigations were carried out in cooperation with

other Government departments, including tests of a Yarian generator set for the Signal Corps, test of a National Geselschaft engine

for the Motor Transport Corps, and investigation of the characteristics of a number of German motor trucks delivered to this country

under the terms of the armistice.
108 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

INFORMATION, TESTING, AND PUBLICATIONS.

Information, Activities in Societies, etc. An important part of the division's activities has consisted in

furnishing information on scientific and technical subjects related

to its work, by extensive correspondence, reports, or directly to technical men visiting its several laboratories. Special reports have been

prepared for the military departments on important problems con- nected with airships. Assistance has been given commercial concerns in suggesting designs for a reinforced concrete cap for timber

columns to prolong the fire-protection period for such columns; to a testing laboratory in the design of equipment for fire tests: and

to various organizations in the choice of materials for fire-resistive construction.

Members of the division have cooperated in the activities of various

scientific and technical societies, including the Society of Automotive

Engineers, the American Concrete Institute. American Society for

Testing Materials, National Fire Protection Association, the American Physical Society, the Optical Society of America, the American

Society of Refrigerating Engineers. Over 30 papers relating to the

work of the division have been presented before scientific and technical societies. 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 thermometers, submitted for test was 3,267, of which £,818 were certified and 1,166 received reports, the failure to receive certificates being due either to defects or to the fact that the errors ex- ceeded the established tolerances. Of the remaining thermometers.

141 were broken either when received or in test, and 142 were rejected. Among those submitted were 407 Parr calorimetric thermometers, 120 high-precision calorimetric thermometers, 195 Beekman thermometers, 101 clinical standards, and the remainder laboratory and special thermometers of various types, ranging from below

up to 500° C. Of the 25,658 clinical thermometers submitted,

21,946, or 85.5 per cent, were certified. The greatly increased number

of rejected thermometers as compared with previous years was due

principally to an excessive proportion of defective thermometers in

several large lots submitted by the Bureau of Animal Industry. In

addition to the above, there were tested 20 resistance thermometers

and 20 thermocouples, while freezing-point determinations were made on 20 samples of materials.

Among the miscellaneous tests may be mentioned service tests of

locomotive superheater thermometers; comparative tests of various

psychrometers ; performance tests of deep-sea thermometers of American manufacture, one of which proved fully as satisfactory as any of

foreign make, which had before been used exclusively ; investigative

tests of one type of recording thermometer; and determination of

boiling points of eight alcohols in cooperation with Px-of. Brunei, of

Bryn Mawr College.
REPORT OF DIRECTOR OE BUREAU OE STANDARDS. 109

The amount of work completed in this section during the year is about 20 per cent in excess of that done in the preceding year and

nearly 100 per cent in excess of that done in the fiscal year 1918.

This increased work was accomplished with practically the same per- sonnel through modifications in testing methods.

In the high-temperature laboratories, tests of the following instruments were made : Xinety-nine thermocouples, 8 indicating instruments for thermocouples, 9 homogeneity tests of thermocouples, 10

optical pyrometers, and 10 optical pyrometer lamps, 55 melting

points, including metals, alloys, and refractories, were determined

and 6 special tests were completed. One hundred and thirty-five

samples of metals with certified melting points were distributed.

The heat measurements laboratory distributed 443 standard-combustion samples. Several miscellaneous heat tests were made.

Of the routine testing summarized above, about half was done for

the Government and half for the public.

In the section dealing with the fire-resistive properties of struc- tural materials numerous investigative tests were made in connection

with the researches in progress in that section. Tests were also made for the Navy Department of the probability

of spontaneous combustion in certain sound-proofing materials.

A considerable amount of testing done by the section on automotive-power plants, fuels, and lubricants, being of an investigative

character, is summarized under the work of that section.

Publications.

The following papers relating to the work of the division have been

published during the year : Optical and Radiation Pyrometry (Paul D. Foote and C. O. Fairehild) : Bull. Am. Inst. Min. and Metal. Eng's. No. 152, p. 13S9. August, 1919. Metals for Pyrometer Standardization (C. W. Waidner and G. K. Burgess),

ibid., p. 1511. Melting Points of Refractory Materials (Leo I. Dana), -ibid., No. 153, p. 1571, September, 1919. Recording Pyrometry (C. O. Fairehild and Paul D. Foote), ibid., p. 1627. Pyrometry in Rotary Portland Cement Kilns (Leo I. Dana and C. O. Fairchild ) . ibid., p. 1661. High Temperature Thermometers (R. M. Wilhelm), ibid., p. 1687. High Temperature Control (C. O. Fairehild and Paul D. Foote), ibid., p. 1701. Annealing of Glass (A. Q. Tool and J. Valasek), ibid., p. 1945. Standard Scale of Temperature (C. W. Waidner, E. F. Mueller, and Paul D.

Foote). ibid., p. 2051. Thermoelectric Pyrometry (Paul D. Foote. T. R. Harrison, and C. O. Fairchild), ibid., p. 2631. [The above papers are also included in the volume " Pyrometry " published by the American Institute of Mining and Metallurgical Engineers.]

A New Galvanometric Method for Measuring Thermoelectric Emf's. (T. R. Harrison and Paul D. Foote) : Jour. Am. Inst. Elec. Eng's, 39, p. 165, 1920. Melting Point Methods at High Temperatures (L. D. Dana and Paul D. Foote) : Chem. and Met. Eng.. 22, p. 23, 1920, ibid., p. 63. Ionization and Resonance Potentials for Electrons In Vapors of Lead and

Calcium (F. L. Mohler. Paul D. Foote. and H. F. Stimson) : Sci. Papers, Bur.

Stds., 15, p. 724, 1920 (No. 368).

Concerning the Annealing and Characteristics of Glass (A. Q. Tool and J. Valasek) : Sci. Papers Bur. Stds. 15, p. 537, 1920 (No. 358).

A New Micophotometer for Photographic Densities (W. F. Meggers and

Paul D. Foote) : Jour. Opt. Soc. Am. 4, p. 24, 1920.
110 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Determination of Plancks Constant h by electronic atomic impact (Paul D. Foote and F. L. Mohler ) : Jour. Opt. Soc. Am. 3, p. 96, 1919. The Ionization and Resonance Potentials of Nitrogen, Oxygen, and Hvdrogen

(F. L. Mohler and Paul D. Foote) : Jour. Opt. Soc. Am. 4, p. 49, 1920. The Vapor Pressure of Ammonia (C. S. Cragoe, C. H. Meyers, and C. S. Taylor) : Jour. Am. Chem. Soc. 42. p. 206. 1920. Sci. Papers Bur. Stds. 16. p. 1, 1920 (No. 369).

A Comparison of the Heat Insulating Properties of Some of the Materials

used in Fire Resistive Construction (Walter A. Hull) : Tech. Papers Bur. Sds. No. 130. Fire Tests of Concrete Columns (W. A. Hull) : Proc. Am. Concrete Inst. 16.

p. 1, 1920. Dilution of Lubricants in ('rank Cases of Internal Combustion Engines (G.

A. Kramer) : Jour. Soc. Autom. Engs., February. 1920, p. 123. Preignition and Spark Plugs ( S. W. Sparrow : Ibid. February, 1920, p. 62. Flying an Airplane Engine on the Ground (S. W. Sparrow) : Ibid. April,

1920, p. 239. A Study of the Velocity of Flame Propagation in the Cylinders of Aircraft Engines ( R. K. Honaman and D. Mackenzie : Ibid, February, 1920, p. 119. Design Factors for Airplane Radiators (S. R. Parsons) : Ibid, June, 1920,

p. 437. Some Factors of Engine Performance (V. R. Gage) : Ibid, June, 1920, p. 402. The Design of Cooling: Surfaces for Air Cooled Engines (W. B. Brown) : Autom. Ind., June 10, 1920, p. 1352. Mouel Metal for Engine Valves (S. W. Sparrow) : Ibid, April 15, 1920, p. 904. The following papers are in press

:

Pyronietry and Applications to Glass Manufacture (Paul D. Foote and L. I. Dana ) : To appear in Glass Manufacture.

Atomic Theory and Low Voltage Arcs in Caesium Vapor (Paul D. Foote and

AV. F. Meggers) : To appear as Bur. Stds. Sci. Paper and in London Phil. Mag.

Pyrometrie Practice (Paul D. Foote, C. O. Fairchild, and T. R. Harrison) : To appear as Bur. Stds. Tech. Paper.

Ionization and Resonance Potentials of Gases and Vapors (F. L. Mohler and

Paul D. Foote) : To appear as Bur. Stds. Sci. Paper.

Pyronietry (G. K. Burgess and Paul D. Foote) : To appear in Standard Handbook for Electrical Engineers, revised.

Specific Heats of Sodium Chloride Solutions, to appear in Jour. Am. Soc. Ref. Engs. and a Bur. Stds. Sci. Paper.

Gravitation and Relativity (C. AV. Kanolt) : Lectures given before the Physics Club of" the Bureau of Standards, to appear in Jour. Franklin Inst. Fire Tests of Building Columns (AA\ C. Robinson. R. E. AA'ilson, S. H. Ingberg,

and H. K. Griffin) : To be published as a joint report of the Associated Factory

Mutual Fire Insurance Companies, the National Board of Fire Underwriters,

and the Bureau of Standards ; also as Bur. Stds. Tech. Paper.

A series of 21 papers listed in the previous annual report have

been issued as part of the Fourth Annual Report of the National

Advisory Committee for Aeronautics.

The following papers will be published in the Fifth Annual Report of the National Advisor}7 Committee for Aeronautics

:

The Properties of Fiat Plate Radiators ( S. R. Parsons).

Properties of Fin and Tube Radiators ( S. R. Parsons).

Properties of AA'histling Radiators ( S. R. Parsons).

Effect of Yaw on Radiators ( S. R. Parsons). Pressure Drop in Air Tubes of a Radiator (S. R. Parsons).

Comparison of Hector Fuel with Export Aviation Gasoline (H. C. Dickenson,

A". R. Gage, and S. AV. Sparrow).

Comparison of Alcogas Aviation Fuel with Export Aviation Fuel (A*. R. Gage,

S. W. Sparrow, and D. R. Harper).
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 1J 1

4. OPTICS.

The work of the optical division includes the following principal lines of activity: Spectroscopy, devoted to radiation and absorption spectra, along with certain phases of qualitative and quantitative chemical analysis for which these are specially applicable, and the develop- ment of infra-red photography for astronomical observations and aviation purposes; polar- imetry, devoted to investigations and tests involving measurements of polarized light and its application, especially in the testing, sandardization, and technology of sugar, including the

supervision of the sugar laboratories of the Customs Service; colorimetry, concerned with the measurement of the factors which determine color, the optical transmissive and reflective properties of materials, and the color grading of light sources and materials; refractometry and optical instruments, interested chiefly in the performance and development of optical in- struments and materials, including refractive indices and dispersion measurements; radiometry, which covers the more general field of radiation, determination of the fundamental constants

of radiation, the development of radiometric methods and instruments, and the determination

of the emissive, reflective, and absorptive properties of materials for thermal radiation; photographic technology, concerned with the investigation of photographic apparatus, testing of photographic materials and devices, standardization of testing methods, and general photo- graphic investigations; interferometry, which makes use of the light wave as a standard

unit for high precision length measurements and develops the application of interference methods. It includes also the optical investigation and measuring of the physical properties of dispersoids, such as smoke, water supplies, etc., and investigations in cooperation with the Engineer Corps of the Army on the conditions governing searchlight illumination, with especial reference to the testing and improving of searchlight mirrors and search- lamp performance.

SPECTROSCOPY.

Wave-Length Measurements.

Although emission spectra of the chemical elements have been the

object of extensive and intensive study for over a century, practically none of them have as yet been completely described and their importance, both theoretical and practical, increases more rapidly than

the knowledge of them is advanced. The significance of spectral

series is beginning to be realized in connection with atomic models

and radiation theorjr, and the actual possibilities in practical spectral

analysis can be fully realized only after much more spectroscopic

investigation.

Spectroscopic data are especially scarce and inaccurate for the

yellow, red, and infra-red light waves to which the ordinary photographic materials are insensitive. With the use of photographic

plates stained with photo-sensitizing dyes the Bureau has devoted

itself to the longer wave portion of spectra for several years and has

studied the arc spectra of most chemical elements to the limit set by

our photographic methods and apparatus. During the past year it has issued Scientific Paper No. 372, containing measurements of wave

lengths longer than 5,500 A in the arc spectra of seven elements

titanium, vanadium, chromium, manganese, tungsten, molybdenum,

and uranium. Wave-length measurements in the yellow, red, and

infra-red spectra of gold, silver, lead, zinc, tin, aluminum, cadmium,

mercury, bismuth, and antimony were completed and collected for

publication. Similar measurements have been made in the arc

spectra of rare earths and uncommon elements like cerium, lanthanum, yttrium, erbium, holmium, neoclymium, samarium, zirconium,

columbium, gadolinium, europium, dysprosium, etc. These spectra

are very complex and involve a large amount of labor to complete

their description. All the wave-length measurements are made in

International Angstrom units with the aid of working standards

measured in the iron arc spectrum by interference methods. (See

Sci. Paper 274.)

Low-Voltage Arcs. Spectroscope work on low-voltage arcs as sources of light waves

gives interesting information on the mechanism of radiation when
112 REPOBT OF DIRECTOR OF BUREAU OF STANDARDS.

. . . . considered m connection with the resonance and ionizing potentials,

which may be regarded as electronic energies required respectively

to agitate and disrupt the atom. Scientific Paper No. 386, on " Atomic

Theory and Low-Voltage Arcs in Caesium Vapor," proves for the

first time the existence of a single line spectrum under conditions

where the atom is agitated but not ionized.

A New Microphotometer.

In connection with the investigation of spectra from low-voltage

arcs, a mieropyrometer was adapted for use as a microphotometer

to measure the densities of spectral lines. This instrument has been

described in Scientific Paper No. 385. Spectroscopic Analysis.

Spectroscopic analyses of more than a hundred samples of materials were made in this laboratory during the past year. Some of

these examinations were to test new analytical methods of chemistry

and methods of purification. A large variety of materials were ex- amined, among them being platinum, palladium, iridium, gold, sil- ver, aluminum, calcium salts, welding wires, bronzes, tool steels, etc. At the request of the United States Treasury spectroscopic analyses of

mint gold were made and spectroscopic methods of obtaining quantitative determinations of impurities in gold have received attention.

Standard samples of pure gold alloyed with known amounts of sil- ver, iron, and copper, which are the common impurities, have been

made. Study of the spark spectra of such standard samples permits

the interpretation of similar spectra of other samples, and yields a method of quantitative analysis which is rapid, especially sensitive to small amounts of impurities, and within certain limits satisfactorily reliable and accurate. False Spectra From Diffraction Gratings.

The long photographic exposures required to extend observations

of spectra in the infra-red revealed some new types of false spectra

given by diffraction gratings. Gratings must be studied very care- fully to separate the false lines from the real. Such a study was made of eight large concave diffraction grat ings, all of which showed

false spectra, which indicate periodic ruling errors of one or more

types. A discussion of the results is to be published in the near

future.

Spectrum Tubes.

Nearly 100 spectrum tubes filled with hydrogen, helium, neon, argon, oxygen, and mercury were made to serve as sources of monochromatic light for optical testing or wave-length measurement.

Most of these tubes were distributed among astronomical observatories, universities, and industrial research laboratories, this Bureau

being during the war period the chief source in this country of such

apparatus.

Photosensitizing Dyes.

The importance of establishing a dye industry in this country

has brought about a large amount of research on methods of making

dyes of many kinds. Some of the dyes used in photography to
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 113

make emulsions sensitive to the longer waves of the spectrum were

produced in this country soon after their importation from abroad was cut off by the war, and research work on these photosensitizing

dyes is still in progress. Forty-three samples of dyes made by the

Bureau of Chemistry of the Department of Agriculture were tested

by the Bureau of Standards for their photosensitizing action.

These samples include pinaverdols, which sensitize for green and

yellow light; pinacyanols, sensitizing for orange and red; krj^ptocyanin for deep reel; and dicyanin, which makes the photographic

emulsion sensitive to red and infra-red light. Methods of using

these dyes and the advantages derived from their use were described

in a circular on " Color Sensitive Photographic Plates " and in a paper on " Dyes for Photographic Sensitizing " appearing in the

Journal of the American Optical Society, May, 1920, and which

will be published later in more complete form by the Bureau.

Aerial Photography.

Experiments in the use of color sensitive photographic plates for

aerial photography have continued along the lines presented in

detail in the annual report of 1919, pages 115 to 119. A series of

interesting tests were made with a multiple lens camera loaned by

the Army Air Service. This camera was fitted with four lenses

containing ray filters and permitted the simultaneous exposure of

four different kinds of plates for purposes of comparison. The

penetration of haze by means of photography with red light was

strikingly demonstrated by these experiments and the increase in

speed of commercial panchromatic plates by treatment with ammonia

was shown.

More recently some experiments have been made to discover just

what part of the " characteristic curve " (relationship of developed

density or blackness to the corresponding exposure) of a photographic plate is generally used in aerial photography. Various

types of plates are exposed from airplanes in a calibrated camera and these plates are subsequently developed together with strips

of similar plates exposed in a sensitometer. The comparison of

densities in the aerial negative with densities in the sensitometer

strips indicate some of the characteristics desirable in plates suitable

for aerial photography. A report on these experiments is beingprepared.

Tests of Photographic Emulsions.

In cooperation with the photographic laboratory of the Bureau

the important characteristics (speed, development factor, contrast,

fog, resolving power, color sensitivity, filter factor) of all photographic plates and films made in America have been investigated.

These data are being collected in preparation of an atlas of photographic emulsions. This work is described in greater detail under

" sensitometry " in the report on " Photographic Technology."

Laboratory for Special Photographic Investigations.

Plans and some preparations have been completed for the equipment of a special laboratory for investigations of photographic

problems of scientific interest. 10613—20 8
114 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

POLARIMETRY.

Developments in Polarimetric Work.

General recognition by the sugar industry of the value of the

Bureau of Standards' contributions in polarimetry has resulted in a considerable broadening of the work in this field. The constantly

increasing demand for the standardization of methods of analysis

the standardization of technological processes and for accurate data on the fundamental constants of the sugars and their associate products has been met inadequately, but yet as fully as possible under

existing conditions, by the setting asicle of space and equipment and

the securing of suitable experts to carry on the work. Necessarily,

the process of accomplishing this is a slow one. and has consumed

much time during the year. The Rare Sugars.

The sugar group includes a relatively large number of substances

each of which, in a physical and chemical sense, is a true sugar. It

is only by means of the systematic study of the whole group that

progress has been made in determining the true chemical composition of the common sugars. Even at present the exact chemical

formula of cane sugar is in a state of some uncertainty.

Many members of this group have a very limited distribution in

nature : many occur only as constituents of more complex chemical

individuals, and many are of common occurrence, but are difficult to

isolate and purify.

The chemistry of each one of these sugars contributes by analogy,

or direct deduction, to the chemistry of the whole group. In a pure

state, they have a variety of uses, the most important of which is at present the differentiation of pathogenic bacteria. For this purpose

the sugar must must be in a state of high purity. In order to ascer- tain the degree of purity, it is necessary to know accurately the

properties of the pure substance. With this end in view, the Bureau

has undertaken to determine the optical rotation (polariscopic

effect), reducing power, and such other properties as are required

to form complete specifications for a pure product.

The demand for the rare sugars and their associated compounds

for use in various scientific fields and in medicine has greatly in- creased during the past year. The complexity of modern civilized

life is such that a substance of scientific interest only to-day fre- quently becomes of commercial importance to-morrow. This fact

has been exemplified in a number of instances in the rare-sugar in- dustry. There are now a number of large concerns producing these

substances. Their product is often necessarily impure, but it is the best that can be done with the available scientific data. Formerly, the only available source of supply for these materials was

the German-made product. As a result of the development of the

industry in the United States, importation has not only practically

ceased, but a A'ery considerable export business has developed, particularly with the South American countries. The Bureau has as- sisted the American manufacturer in every way -possible. The

necessity of obtaining these materials in pure form for the War De-
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 115

partment and for the medical profession has necessitated the hurried

preparation of indispensable scientific data on certain of the sugars. At the same time, plans have been completed for a section devoted

to the development of the necessary scientific constants and other data

needed in this field. The results obtained have been most encouraging.

During the year, a number of these rare sugars have been submitted by the War Department for test. This test necessitated a

purification and determination of the properties of each substance,

since no reliable data exist. The tests showed that but few of the

sugars were highly purified. Many were so impure that they were

rather of the nature of crude substances. Inasmuch as the Medical

Department of the Army had already completed important bacteriological work on these sugars, the urgenc}^ of obtaining complete

specifications is apparent.

Among the sugars studied are arabinose, raffinose, xylose, rhamnose, melibiose, dulcite, and mannite.

Optical Properties of Oils.

Oils, whether mineral, fattj% or essential, are extremely complicated mixtures, and as such are very liable to adulteration. It has

been found that certain optical tests, among which the polarimetric

tests are important, are very useful in determining the composition

and purity of these substances. Many oils are naturally active;

that is, they produce a rotation of plane polarized light, to a more

or less extent, while all become active to varying degrees in a magnetic field, and are double refracting in an electric field. Complete data on these optical effects for different colors of light should

lead to the formulation of an adequate theory which would be of

great aid in determining the composition and molecular structure of

oils. These results, taken in conjunction with other physical and

chemical data, should also be very valuable in determining the suitability of any of the oils for commercial purposes, such as foods,

fuels, paints, lubricants, etc. The polarimetric study of oils is a new field which the Bureau

has entered, owing to the continued demand for scientific data. Alreadjr several of the large oil consuming companies are using these

physical tests, owing to the fact that, even in their present crude

form, they are the only means available for grading crude oils for

certain purposes. Considerable work has been done on preliminary

investigations and in collecting and coordinating the data at pres- ent available on this subject, as well as in devising methods and

preparing apparatus for the testing and further investigation of all commercial oils. Testing of Quartz Control Plates.

A plate of crystalline quartz, cut perpendicular to the axis of the

crystal, has the same influence on the direction of the plane of vibration of a light wave as a sugar solution. Science has taken advantage of this fortunate circumstance to provide a positive and un- changeable device in the form of the quartz control plate

for checking the accuracy of saccharimeters. The complicated
ne REPORT 01" DIRECTOR OE BUREAU OF STANDARDS.

saccharimeter may easily get out of adjustment, thereby rendering

uncertain the test of a sugar. Any inaccuracies clue to this condition are wholly avoided by placing a quartz control plate in the

instrument and comparing the reading with the accepted value of

the plate. These plates are thus of fundamental importance

throughout the sugar industry and in all scientific laboratories. During the year, 29 were tested, 10 of which were for European concerns; the others for various sugar companies. Two were rejected as being totally unfit for saceharimetric use. Several were improperly mounted in wax. These were removed from their original

mounts and remounted in loose metal holders so as to comply with

the Bureau's specifications.

On account of the difficulty of obtaining control plates, and with

the idea of being of the greatest possible assistance to the sugar

industry, the Bureau has. whenever feasible, undertaken the re- mounting and testing of improperly mounted plates. This procedure

serves to make reliable many plates which would otherwise be

unfit for accurate work. On account of the fact that many of the

plates now being received are. of unknown origin, it is more than

ever important that they be critically examined for defects. As an

aid in accomplishing this, apparatus has been set up for testing the

planeness and parallelism of the plates and measuring the " axis

error." i. e., the angle between the crystallographic or optic axis of

the plate and the normal to the plate. These tests are made in addition to the usual tests for homogeneity and sensitivity in the polariscope. Advantage has been taken of the Bureau's wide experience to draw

up a set of preliminary specifications as a guide to manufacturers

in producing first-quality control plates.

An important service is thereby being rendered the entire sugar

industry, as it will render available a supply of uniformly good

plates of American manufacture.

Acidity Measurements on Refined Sugars.

A complete description of the properties of a sugar product should

include a measurement of its " reaction." By " reaction " is meant

the degree of acidity or alkalinity of the sugar when dissolved in

pure neutral water. An accurate method of determining this property of refined sugars has never been available. This condition has

persisted in defiance of the generally recognized fact that the acidity was probably affecting the usefulness of the sugar for many purposes to a profound degree. Measurements were made on about 150

samples of commercial white sugars. A cqlorimetric method which

has been extensively developed elsewhere has been adapted to this

purpose. A number of indicators (organic substances whose colors are extremely sensitive to the reaction of a liquid) haATe been developed and their colors related exactly to the reaction in question. Of

these indicators, seven or eight of which have been found to cover about the whole range of reaction of naturally occurring substances,

two were found sufficient to indicate the reactions of white sugars. Some sugars were found to be acid, the greater number approximately

neutral, and some alkaline.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 117

Those which were found to be acid or alkaline were reduced (ti- trated) to exact neutrality, and the quantity of reagent necessary

to produce neutralization carefully measured. Striking differences were observed. Many substances, having the same acidity, required

very different quantities of reagent to produce neutrality. This fact

indicates variations in the nature of the impurities and suggests the

presence of " buffer " substances, i. e., substances which resist a change in reaction.

While the actual magnitude of the alkaline or acid substances

amount to but a few ten-thousandths of 1 per cent, the variations in

their quantities exert fundamental effects on sugars when used for

certain manufacturing processes. While it is too early to predict the

results of this study, it is possible that an intimate relation exists between the reaction and the "strength " of the sugar. " Strength " is a term used by candy manufacturers to designate the behavior of

sugar when boiled at a high temperature. The exact definition of this

term and its correlation with other properties must aAvait further

study.

ioo° Point of the Saccharimeter Scale.

In the previous report attention was directed to the fact that the

Bureau had inaugurated the policy of standardizing all saccharimeters and quartz control plates on the new value of the 100° point.

The investigation covering the determination of this fundamental

constant, on the value of which all sugar throughout the world is bought and sold, has been discussed in previous reports. Owing to the fact that the error discovered in this constant was a relatively

large one, the Bureau delayed putting the new value into effect in the

hope that international agreement might be secured. When it seemed

impossible to bring this about, the new value was put into effect by the Customs Service. The wisdom of this procedure has been

amply proven by the fact that the developments in international

scientific relations have tended to postpone indefinitely any agreement on this important matter. Vigorous efforts were made during

the past year by many interested parties to bring about a session of

the International Sugar Commission to discuss the matter, but without result. United States Customs Laboratories.

The modern chemical laboratory which the Bureau designed for

the Customs Service at Boston and which contains a number of in- novations has noAv been in operation for over a year with most satis- factory results. It has not been found necessary to modify either the

design or the equipment, and it is being used as a model laboratory

throughout the service. An opportunity similar to that at Boston was developed by the

remodeling of the United States customhouse at New Orleans.

Advantage was taken of this opportunity to provide suitable quarters

at that port for the installation of a modern customs laboratory similar to the Boston laboratory. Detailed specifications and plans drawn

up by the Bureau have resulted in giving the port of New Orleans a laboratory replete with all modern facilities. The importance of
118 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

these laboratories to the Treasury Department is shown by the faci that over 60 per cent of all the revenue from customs is collectec either directly or indirectly through the customs laboratories.

Sugar and Molasses at the Smaller Ports. Large as have been the importations of sugar and molasses through

the small southern ports in recent years, a still further volume was

handled during the past 12 months. Owing to the fact that it is impracticable for the Customs Service to maintain the necessary equipment and testing facilities at any except the large ports of entry, it was found necessary to devise methods of transmitting samples from

small ports to the larger ones for testing. These methods devised by

the Bureau of Standards for this work have proven satisfactory and

will be continued indefinitely.

Definitions and Specifications of Commercial Sugars.

Work on the problem of preparing standard definitions and specifications for refined sugars has been continued uninterrupted. The

investigation has developed into a more extensive one than was anticipated. Over 250 samples have been sj^stematically studied by means

of chemical analysis, size of crystals, moisture content, color, and

other chemical and physical properties. The results so far obtained

have proven interesting and valuable. The data are so extensive that

it is planned to publish them as a separate circular, and it is hoped

will permit of accurately preparing a scientific definition of each of

the necessary grades of commercial sugars. At the present time, there are about 40 varieties of sugar on the

American market that are suitable for direct consumption. The

trade names give little or no indication of the character of the sugar.

It is believed that the accurate classification, for which the Bureau

is striving, will be of great benefit to both the consuming public and

the manufacturer.

Color of Sugars and Sirup.

An important factor in the grading and standardization of sugars

and sirups is a definite statement of the color. The value of these

commodities depends in no inconsiderable degree upon this factor. Unfortunately, a great deal of confusion has always existed, and no

strictly accurate and scientific method has been made sufficiently

simple to be practical for routine industrial use. During the year

the polarimetry and colorimetry sections of the Bureau have developed a simplified method which gives accurate data on a scientific basis and a colorimeter has been constructed. It is applicable to the

grading of raw sugars and sirups and many other materials which

are normally in a liquid state or can be feasibly examined in this

state by fusing or dissolving.

This method is not satisfactory for the examination of white granulated sugars, both because other factors beside the color enter into the

appearance of the crystals, and because making a solution of the

sugar is too tedious. For this purpose no method has yet been made

to equal in sensitiveness and accuracy the viewing of the sample to be

graded under standard illumination beside a series of arbitrarily
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 119

graded samples covering the range desired. The Bureau is now

working on a method for the direct examination of white sugar, which

will indicate the color-grade on a rational scale of reference.

Preparation of Levulose.

Levulose is one of the most abundant of the sugars; the great

difficulty of isolating and purifying it make it one of the most costly

sugars on the market. Owing to the fact that it is the sweetest of all sugars, that it is easily digestible, that it is abundant, and that it has

many uses in bacteriological and chemical laboratories, its production

in quantity would make it an important commercial and scientific commodity.

The Bureau has experimented with the method of separation of

levulose from invert sugar of which it is a constituent. This separation, which is accomplished by means of lime at low temperatures,

has been studied with the purpose of finding the optimum conditions

of concentration of sugar and lime. Under favorable conditions, a

yield of 85 per cent has been obtained in small-scale experiments.

The influence of the other constituent of invert sugar, namely, dextrose, has been ascertained. About 10 pounds of levulose has been

prepared for furtner investigation.

Work is now in progress on its preparation from other sources of

supply. The combined results so far obtained in this important sci- entific and commercial problem indicate the early development of a method of production which will make levulose available in quantities

for all purposes anci at a materially reduced cost. Analysis of Sugar Mixtures.

The investigation in this subject, including the redetermination of

the Clerget constant, has been completed. Impure sugar products

always contain optically active substances which influence the reading of the polariscope in much the same manner -as sugar itself. Therefore, a single reading of the polariscope is merely the resultant

effect of all the substances present, and consequently does not indicate

the true percentage of sugar. In order to effect the analysis of sucrose, it is necessary to supplement the first reading of the polariscope or direct polarization by a second observation in which the rota- tion (i. e., polariscopic effect) of the impurities is maintained unaltered, but in which all of the sucrose has been changed by the action

of acids to invert sugar. The latter is a mixture of two simpler sugars

which has a rotation in the opposite direction from that of sucrose. The total change in rotation of pure sucrose is 133.25° at 20° C. This

value is known as the Clerget constant and is of fundamental importance in sugar analysis. The previously used value of 132.66° was

thus found to be in error by nearly 0.6°. In using this method of analysis, certain precautions must be taken

to guard against an error arising from the lack of constancy of the

rotation of impurities. Thus the investigation has shown that if in- vert sugar is present in the original sample taken for analysis, a weight of salt equal in weight to the acid used for inverting the sugar

must be added to prevent a change in the rotation of the original

invert sugar. This, however, changes the value of the Clerget constant by an amount that was accurately determined. Similarly the
120 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

presence of other classes of impurities has necessitated minor modifications in the analytical procedure, each of which has required an

accurate determination of the value of the (Jlerget constant. The investigation has made it possible to express by a simple

formula the value of the constant under a wide range of conditions

and thus to select from current literature those determinations which

are accurate. In this manner a number of recent determinations of

the Clerget constant, made under widely varying conditions, were

correlated within the limits of accuracy of the measurement. Previous to the establishment of this formula these values were isolated

empirical quantities, having little apparent relation to each other.

Raffinose in Beet-Sugar Products.

In continuation of the work on the analysis of sugar mixtures,

satisfactory progress has been made in extending the methods developed to the determination of sucrose in the presence of other disturbing impurities. The most urgent need is that of the estimation of

sucrose in beet products which contain " raffinose." " Raffinose " in

beet products, as determined at present, includes a number of substances to which is assigned a rotaiw power equal to that of pure raffi- nose, a pure sugar occurring in beet juices. It is well known that

but a portion of these substances are truly raffinose, but no method

of distinguishing them is as yet known. Consequently, the Clerget

analysis of beet products does not represent correctly either the true sucrose or the true raffinose content. Picnometer for Viscous Materials.

Accurate determination of the density of a viscous liquid has longbeen a difficult problem. The major difficulty lies in the large quantities of air or other gases, which, owing to the high viscosity of the

liquid, can not be liberated except by heating. For many substances,

such as molasses, this procedure is not permissible. The Bureau has

brought about during the past year an improvement in existing conditions for density determinations by designing and perfecting a picnometer, through the use of which errors clue to included air and

evaporation are to a very great extent eliminated. Increased accu- racy in this work, which is important both for scientific and commercial purposes, has been attained. The results of the investigation including a description of the device were published.

Testing of Molasses.

The Bureau continued to act as referee between buyers and sellers in the polariscopic analysis of molasses. Practically all molasses for

manufacturing purposes is bought on the basis of sugar content and

density. A number of manufacturers specify in their contracts that

the Bureau shall act as referee in the event that a controversy arise. During the year, the Bureau acted as referee in 11 cases where large sums of money were involved. By using the Bureau's corrected value

of the Clerget divisor it has been found possible to attain a higher

accuracy in the estimation of the sucrose content of molasses. The

methods available for the determination of density are still under

investigation. One applicable to commercial analysis has been devised which gives satisfactory agreement with the method using the

picnometer, previously described.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 121

Standardization of Sugar Manufacture.

Although the manufacture of sugar from the juices of the beet

and cane has been carried out for a great many years, and very few

changes have recently been made in the general methods of the manufacture of either of these kinds of sugar, yet there is great diversity

of opinion and practice as to the details of almost every process in- volved. This uncertainty is due, first, to a lack of definite scientific data, especially that pertaining to the physical chemistry involved;

and, second, to the fact that there has been no central bureau with

facilities for the study and adequate coordination of the information

already acquired in various ways by manufacturers and others. In

recent years, corn sugar or dextrose, and still more recently, malt

sugar or maltose, are appearing in large tonnages.

The need for standardization is now being felt by the whole sugar

industry. The great corporations operating chains of factories or

plantations have done much to standardize methods within their

own organizations, and some even have their own well-organized

research departments. They are, however, as insistent as the small

manufacturer in their demands on the Bureau for research and

standardization, because there is still left a vast field which only a

central, unbiased, well-equipped agency, such as the Bureau, can

cover satisfactorily.

Molasses Formation.

The juices and sirups, from which all kinds of commercial sugars

are made, consist, in each ease, of a complex solution containing the

sugar in question and a large number of impurities. Some of the

sugar is removed by crystallization, leaving most of the impurities

still in solution. This process may be repeated several times, but

before all the sugar is removed a point will be reached where sugar

will no longer crystallize, because it is held in solution by the impurities. This residue is molasses. Some impurities decrease the

quantity of sugar retained in the molasses, but most of them increase

it. Small differences in the details of some of the processes used in

the manufacture are known to influence greatly, on the one hand,

the amount of impurities introduced from outside sources as well

as those extracted with the juice; and, on the other, the amount of

impurities removed in the various purifying treatments before crystallization is begun. The solubility curves of several sugar-salt sys- tems have already been worked out. This investigation covers a wide field and is of economic importance. Several parts of the work

are already outlined and under way.

Beet and Cane Molasses.

In most beet-sugar factories the residual molasses from the crystallization processes is treated chemically to separate the sugar from

the accompanying impurities which keep the sugar in solution. In

factories located in the Middle West and northern portions of the- United States the process in use results in the accumulation of a substance which is optically active and forms solutions of great viscosity, thus interfering with chemical control of the processes on

the one hand, and with the actual process of crystallization on the

other. The Bureau is carrying out work on this substance with
122 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

three principal objects in view: To develop, first, a method of analysis which will avoid or eliminate the interference of this substance

in the polarization of sugar; second, a method of minimizing its deleterious effect on the crystallization of sugar, and, third, a possible method of minimizing or avoiding its formation and accumulation. Considerable progress has already been made.

Decolorizing Carbons.

One of the most important recent developments in the cane-sugar

industry is the general movement for the production of " directconsumption " sugars ; that is, sugars which are fit for consumption

without further refining. A most important factor in this development promises to be the use of the new decolorizing carbons, of

which a number have appeared upon the market, and for which patents for many more have been granted. A detailed study for the

standardization of these substances is well under way. The research

will include other clarifying agents, and promises to be of value also in the production of new types of beet sugar and in the manufacture of corn and malt sugars. Gradation of Sugars by Sieve Analysis.

The Bureau has at its disposal over 225 samples of the various

sugars submitted by the principal producers in the United States. A careful comparative examination of these sugars shows the lack

of a systematic method of grading by the size of the crystal. For

the elimination of confusion, such as occurs between the producer

and the consumer, the Bureau has undertaken a systematic study of

the gradation of sugars by screen analysis. As a result of the data

already obtained, specifications will be submitted which will materially help to define the sugars now sold on the American market,

and also help in the advancement of the standardization of the

sugar industry.

Diffusion in Beet-Sugar Production.

In beet-sugar factories it is possible for the quantity of impurities

removed from the beets along with the sugar to vary greatly with

the method of diffusion. The effects of the various factors involved

are not well understood, and certain lines of work are now under way

to elucidate the principles underlying each effect, and thus establish a standard practice which can be applied to all conditions. This

work is of fundamental importance to the beet-sugar industry, and

it is expected to prove of considerable value in cane-sugar practice

as well. Production of Mannite.

The production of d-mannite of high purity from crude manna

has been continued, with the twofold object of obtaining needed

scientific data on this important sugar and of creating a sufficient supply to meet the needs of the medical service of the Army. Both

objects have been attained. Extensive experiments have been con- ducted on the purification of mannite. using a new commercial vegetable carbon as the decolorizing agent. Solutions of high purity were obtained from which excellent yields of white mannite were

taken. In addition, other methods of decolorizing and purifying the
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 123

crude liquors have been studied. An experimental plant has also

been designed which will be suitable for the purification of mannite

and other materials.

A study of the optical rotation of mannite is being made with the

view of defining specifications of purity for this material.

Society of Sugar Chemists and Technologists.

Owing to the fact that the sugar industry of the United States is the most diverse of any nation, the necessity for some organization

which would bring together the large numbers of scientific and technical men in its various phases has long been especially acute. Under

such circumstances the interchange of ideas resulting from such an

association benefits to an unusual degree not only the individual

members but also the industry as a whole. Because of this situation,

and by request, the Bureau has for some time been rendering its assistance in every way possible to the formation of a society of

American sugar chemists and technologists. In view of the fact

that many persons desired to attend the meetings of the American

Chemical Society and for other reasons, it was finally decided that

the proposed society should organize as a section of the American

Chemical Society. > The initial meeting was held at St. Louis. Over

60 sugar chemists and technologists were present. The members

represented every part of the United States geographically and

every phase of the sugar industry, including the manufacturers of

the rare sugars, glucose, and the various materials used in the production of sugar. The regular program of the meeting included,

among other things, 15 scientific and technological papers. Previous

experience has demonstrated that where it is possible for such an

organization as this to be perfected, it invariably opens up new

channels which make it easier for the Bureau to extend its usefulness

and cooperation with the industry.

Composition of Sirup.

A considerable portion of the cane sugar produced in this country

is distributed in the form of sirup for direct consumption. The

problem of producing a stable sirup has long been a fundamental

one in the .sirup industry. A saturated solution of pure sugar contains about 67 per cent of sugar. Such a solution is too dilute for a

useful product and moreover is capable of fermentation, and therefore likely to spoil. If more concentrated, it eventually deposits

sugar crystals in the container. This investigation has shown that

if the sugar is partially inverted, the sirup may contain as much as 79 per cent of total sugars, and still remain undersaturated. Such a

sirup, in addition to remaining indefinitely in a state of solution,

resists the action of fermenting microorganisms. By means of extensive solubility determinations, the exact composition of the mixture

which shall have the maximum content of dissolved substance has

been determined.

There are in existence a number of methods of producing partial

inversion. The Bureau has discovered that it may be cheaply and

efficiently accomplished by adding a relatively minute quantity of

hydrochloric acid. The exact conditions of time and temperature

are described in a publication now in preparation. A number of

important by-products have been obtained in carrjdng out this work.
124 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Among them may be mentioned an accurate measurement of the

density of invert sugar solutions, the volume of the contraction and

the change of viscosity which result from the inversion of sugar. The facts developed in this investigation haA'e been recognized as being of importance to the sirup industry and the Bureau has made

one application on a factory scale at the request of the manufacturer.

Crystallization of Sugar.

Most high-grade chemicals are purified by a process of fractional

crystallization. White granulated cane or beet sugar, as it ordinarily

appears on the market, is of a purity equal to that of most of the

" chemically pure " reagents used by the chemist. It, too, is prepared

by a process of fractional crystallization in quantities several times

greater than any other chemically pure commodity. This process is therefore probably used more extensively in the preparation of sugar

than in any other manufacturing business. Nevertheless, a great deal

remains to be learned about crystallization, and particularly about

fractional crystallization, under the various conditions which are encountered in sugar-making. A thorough investigation of this subject has been undertaken by the Bureau, and when it is finished it should be of economic value to the country.

Purification of Sugars.

During the year an important research on the speed of falling of

solid particles through fluids has been completed. It has applications in many processes of clarification and filtration which are used, or have been proposed for use, in the several branches of the sugar

industry- Tavo specific illustrations are the processes of thickening

by settling and centrifligation, and of clarification of juices (including fruit juices) by centrifligation. The results obtained in this

investigation promise to be of importance in the study of ballistics,

quite outside the sugar industry. This work is now being extended

to cover certain colloidal phenomena.

A study of the principles involved in the ordinary processes of

filtration has been outlined and this will be applied to the newer

types of apparatus as well as to the older ones, with the object of

standardizing certain types to fit particular purposes and conditions

of service. Various manufacturers have offered to make up and lend

apparatus for these tests. One phase of this work includes a study

of filter fabrics and their application to the various types of filters. Candy Test for Sugar.

One of the most obscure phenomena exhibited by sugars has been

the wide range of variability of their suitableness for candy-making

purposes. Certain sugars will give excellent results, whereas the

use of similar sugars will often give a product that is not satisfactory.

A reliable method of differentiation of sugars for manufacturing

purposes is urgently needed. The problem has been studied in con- nection with the preparation of definitions and specifications for

commercial sugars. The most definite result has been in the partial

development of a candy test which has already attained a considerable degree of precision, indicating the presence of minute quantities of certain impurities in sugar which enhance or decrease its value for candy making. This test is being further developed to

:
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 125

Increase its intrinsic value and for the purpose of correlating with

it shorter and simpler tests which may possibly be substituted to a considerable extent.

Official Baume Scale.

At the annual meeting of the Association of Official Agricultural

Chemists, representing each State in the Union, the Baume scale proposed by the Bureau was recommended for adoption and action was taken to discard all other Baume scales in the official publication

of methods of analysis. The importance of this step arises from the

fact that there are about 20 scales now in use and that the Baume

density is capable of a varied interpretation. With the single

national definition of Baume density at the standard temperature

of 20° C, these differences should disappear.

Supplies for Customs Laboratories.

The difficulties incidental to obtaining sufficient supplies for scientific laboratories during the Avar have continued throughout the year. This condition has notably affected the operation of the United

States Customs laboratories. Xecessarily, many of their supplies,

as well as equipment, must be purchased under rigid specifications

in order to insure the accuracy necessary in precision work. The

lack of suitable supplies has been further aggravated by the uncertain volume of importations. In order to overcome this condition,

the Bureau has succeeded, through cooperation with the Treasury

Department, in securing a reserve stock of all supplies requiring a Bureau test for acceptance and has set aside a storeroom in which

these supplies can- be held. A sudden shortage at any port can

therefore be relieved by immediate shipment, and delay incidental

to appraisement of imported merchandise thereby prevented. Supplies thus far accumulated include volumetric flasks, polariscopes,

polariscope tubes, polariscope tube cover glasses, bichromate absorption cells, etc. It is planned to gradually extend this procedure to cover many other needed precision supplies. Through the efforts of the Bureau a large supply of polariscope tubes have been obtained

and tested. All tubes in use at the various ports have been re- placed with new ones and the old tubes returned to the Bureau for

test. The previous practice has been when a test tube was placed

in the Customs Service, after it had been standardized at the Bureau,

to permit it to remain there until discarded. The wisdom of return- ing the tubes annually to the Bureau to be tested was shown by the numerous inaccuracies found in the tubes which had been in the

service but a little over a year. It has also been found possible to have the manufacturer renew many of these tubes, thereby saving a considerable sum annually to the Government. The procedure of

the Bureau in this matter is an excellent illustration of what can be

accomplished by cooperative operation between different depart- ments.

Cooperation, with Customs Laboratories.

The work incidental to assisting the Treasury Department in the

maintenance and operation of its customs laboratories has been con- tinued with excellent results. The abnormal situation which has
126 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

prevailed for some months throughout the sugar industry has re- sulted in the heaviest importations of raw sugars the United States has ever known. This is attributable not only to an increased domestic consumption, but also to the fact that large quantities of raw

sugars have been refined in this country for European consumption.

This situation has necessarily created much additional work for the

Bureau. Throughout this abnormal situation the high percentage

of accuracy of the quantities of sugar tests has been successfully

maintained. In this work 1,521 exchange samples of raw sugar for

controlling the work of the sugar laboratories at the customs ports were tested. Approximately 50 per cent were direct polariscopic

determinations for the quantity of sucrose present, and the remainder were tested for the percentage of moisture in addition to sucrose

content. Natural Rotation of Quartz at High Temperatures.

The investigation of the natural rotation of light by crystalline

quartz at high temperatures has been continued. As the temperature

of a quartz crystal rises, the magnitude of the angular rotation of

the plane of polarization of light passing through the crystal in- creases rapidly as the temperature approaches the recrystallization

point at 573.3° C. As this point is approached there occurs a most

profound change in all the physical properties of the crystal. Just

below the inversion point a slight change in temperature causes a very large change in the rotation. The curve expressing the change

of rotation with temperature has been found to be practically a straight line, almost parallel to the temperature axis from the in- version point at 573.3° C. to about 1,500° C. A molybdenum-wound

furnace has been constructed with which it is hoped to push the

observations well above 1,500° C, perhaps to the melting point of

the quartz crystal.

Below the inversion point the law has been developed that the

relative change in the rotation with change of temperature is practically the same, no matter what may be the color of the light passed

through the crystal. The so-called rotation dispersion has therefore been proven to be the same for all wave lengths at all temperatures up to the inversion point.

From the data obtained an equation has been determined which

fits the observation for temperatures up to the inversion point. This

equation can be made to express the change in rotation with temperature for any wave length by multiplying it by an appropriate

constant, i. e., the initial rotation of the quartz for that particular wave length. There is, however, a slight deviation (of the order of a few hundredths of a degree) of some of the observed values near the

inversion point from those calculated from the equation. Subsequent experiments will show whether this is due to inherent experimental error or is a true deviation from the law of constant dis- persion at all temperatures. As stated in last year's report, the

Bureau's polarimetric measurements are the first precision measure- ments ever made at high temperatures.

Adjustment and Standardization of Polariscopes.

The work of adjusting and standardizing polariscopes and sac- charimeters has been continued. The Bureau's facilities have been
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 127

taxed to the utmost to handle all the instruments submitted. The

sugar industry, as well as educational and research institutions, have

been unable for some years to obtain an adequate supply of new

polariscopes. Until recently no new instruments could be obtained.

Owing to the sudden expansion of the sugar industry and the impossibility of obtaining additional instruments, it became necessary to

resort to the use of instruments which had been discarded. Many

of these have a different basis of calibration from those of newer

types. The Bureau has constantly been consulted in regard to the

use of these instruments and has been able to render important

services. Another class of discarded instruments are modern types of

excellent design for manufacturers' and refiners' use, which, however, have been rendered useless through wear or because the optical

parts are out of adjustment.

In connection with the work of rendering these instruments serviceable, a number of related problems have come up and been solved.

As a result of this work, the Bureau has been able to render an

important service to the sugar industry and the public. Many let- ters of commendation have been received. During the year 55 instruments were standardized. After adjustment the scales of all polariscopes submitted were carefully compared with the official standards

of the Bureau and certificates issued showing the corrections neces- sary to be added to the scale readings to give the true rotation in

sugar degrees, based on the widely accepted Bureau of Standards

determination of the international sugar scale. The Natural and Magnetic Rotations and Rotation-Dispersions of

Sugars.

One of the fundamental properties of matter is its power when

placed in a strong magnetic field to so modify the vibrations which

constitute light that if a beam of plane polarized light is passed

through the substance in a direction parallel to the. magnetic field a rotation of the plane of polarization will take place. The rotation

is constant for each substance and is different for different substances,

so that the magnetic rotation of a substance constitutes one of its characteristic physical properties. Measurements have been undertaken on the natural and magnetic rotations of various sugar solutions, more

especially sucrose, dextrose, and levulose, for various wave lengths

of light. The purpose of this investigation is twofold—first, to ac- curately measure and record this additional characteristic physical

property so that it will be available for general use, and, secondly,

to coordinate the data obtained with other known chemical and

physical properties in an effort to solve a number of problems for

which a solution has long been demanded.

Light Filters. The standard light filter for saccharimeters as adopted by the

International Sugar Commission is a layer 1.5 centimeters thick of a

6 per cent potassium bichromate solution. This filter has the disadvantages inherent in a solution. It is awkward to handle, the cells are not permanent, and if inclosed in the instrument the leakage may

damage the optical parts. The solution in time becomes dirty and

has to be renewed. It would be a decided improvement if a perma-
128 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

nent filter, such as a colored glass, could be used in place of the solution. A glass for this purpose should have the same or approximately the same spectral transmission as the bichromate solution, so as not to introduce any error in the saccharimetric readings. With

the object of finding such a glass, several samples have been examined

and an endeavor is being made to obtain specimens from as many

sources as possible.

The question of a light filter for saecharimeters is an important

one, and before making any change from the bichromate filter, as prescribed by the International Sugar Commission, the Bureau must

have conclusive experimental evidence that the change will not affect the saccharimetric readings.

Standard Samples.

During the past year 138 samples of sucrose and 31 samples of

dextrose were distributed. These materials are used principally for

industrial and scientific purposes. There is a steady increase in the

demand upon the Bureau for standard samples of the sugars. Polarimetric Testing.

Large numbers of cover glasses for polariscope tubes were tested

for optical homogeneity and for absence of optical activity. All

glasses tested for the Customs Service were of American manufacture. In addition considerable numbers were tested for private

concerns. Polarimetric Measurement of Strain in Glass.

Practically all glasses, unless carefully annealed, are under great

strain, due to certain parts cooling in advance of other parts. These

strains, incorporated in the glasses during their manufacture, are most easily detected by a light phenomenon which they exhibit, technically known as double refraction. The character of the annealing

which optical glass has received is of great importance in the manufacture of optical instruments. The only practical method of testing

glass for the sufficiency of its annealing for optical and other purposes is to subject it to a polarimetric test, which determines its double refraction. In collaboration with the pyrometry section,

methods of testing glass very accurately for this phenomenon have

been adopted, and tests are being made of the relative degree of

annealing obtained by various methods of treatment. A study of

the stress distribution in glass pieces differently treated and having

different geometrical shapes is also being carried on in order to compare the experimental results with the distribution to be expected

from certain theoretical considerations. It was also undertaken to determine any relation which may exist between the stress distribution and the fitness of the glass for optical purposes.

The object of another investigation on which some preliminary

work has been done is to increase the knowledge of the relationship

existing between the stresses in glass and the double refraction produced by them. The ultimate purpose of these various investigations,

when sufficient data have been obtained, is to establish a more uniform

standardization for the degree of annealing of glass, especially that

intended for optical purposes, which shall take the place of the

arbitrary standards now in use. Several manuscripts covering the

results obtained in this investigation have been prepared.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 129

Commercial Process for Manufacturing Pure Dextrose.

Dextrose or glucose is the sugar which results from a chemical

treatment of cornstarch. It exists on the market as a sirup (corn

sirup) or as a light broAvn aggregate of round solid grains having a purity of about 94 per cent. The Bureau has shown that a pure

white dextrose may be obtained by crystallization from a water solution and may easily be separated from the mother liquor by using a centrifugal machine. Previous methods for the preparation of the

pure substance have demanded the use of alcoholic solvents. The

improved laboratory process obviously would permit of operation on

a large scale and at reduced cost. A member of the Bureau's staff was accordingly sent to a large glucose manufacturing company to apply the process on a commercial .scale of operation. Two processes were investigated. In the one which met with almost immediate

success, the " converted " starch liquor was boiled in a vacuum until

concentrated to 42° Baume and was then dropped into a crystallizer. It was then innoculated with crystals of pure dextrose and agitated

until the crystallization was complete. The Bureau has found that

at a temperature in the neighborhood of 35° C. the crystalline form

of dextrose changes. Below that temperature the substance contains

water of crystallization; above, it is anhydrous. Consequently, it was found necessary to keep the crystal mass above 35° C. in order

to preA^ent the formation of crystals of irregular sizes which prevent

efficient work with the centrifugal machines.

When the growth was finished, the crystal mass was easily sepa- rated from the mother liquor and a satisfactory yield of pure crystalline dextrose was obtained, having the whiteness and purity of

commercial cane sugar. The second and more difficult process was that of accomplishing the

crystal formation directly in the vacuum pan. While this was not

brought to the same stage as the first process, enough was accomplished to show that the process was a feasible one. In carrying this investigation to a successful conclusion, the

Bureau has virtually created a new industry of great magnitude.

There are innumerable uses for glucose, or, as it is more commonly

called, corn sugar. The fact that this material has never been available in pure form at a reasonable cost has prevented its use on a large

scale. The process developed is A

T ery similar to that used in the

production of the best grades of granulated sugar, and the glucose

secured by the new process is a beautiful, fine Avhite crystal. The

cost of production is actually less than the cost of producing the

round, solid, brown material Avhich was formerly produced. The

magnitude of the commercial possibilities of the new sugar is shoAvn

by the fact that one of the largest corporations in the country re- quested the Bureau to design a large scale experimental plant, cost- ing approximately one-half million dollars. This has been done and

the plant is now practically completed.

New Cadmium Vapor Arc Lamp for Polariscopic Uses. For some years numerous experiments haA-e been carried out by

a number of investigators with the object of obtaining a cadmium

vapor lamp similar to the mercury vapor lamp. This has been done

because of the necessity of securing a stable monochromatic red light

10613—20 9
130 BEPOET OF DIEECTOE OF BUREAU OF STANDARDS.

the

uch

source of high intensity. When pure cadmium is distilled into the

quartz lamp and freezes the metal adheres to the silica with such

tenacity as to either crack the lamp or peel strips of the silica from

the walls. If such a lamp be filled with a cadmium mercury alloy,

the cadmium spectrum appears but faintly, and the position of its principal lines in the spectrum with respect to the mercury lines is such that spectrum filtration with a wide slit is impracticable. The

lack of intensity in the cadmium spectrum is due to the fact that its vapor pressure is relatively low compared with that of mercury.

Upon investigating this problem, the Bureau discovered that the

metal gallium would readily alloy with cadmium, and that a very

small quantity, less than 1 per cent, was sufficient to radically change

the character of the cadmium and greatly reduce its tensile strength.

All breakage of the lamp was eliminated. In using this alloy in a quartz lamp the cadmium spectrum is obtained with great brilliancy

and purity. Although gallium melts at approximately 30° C, its boiling point is above 1,600° C, and its vapor pressure is so low that

the spectrum of gallium is practically absent, the cadmium vapor

acting as the carrier of the electric energy. A lamp of this type,

using lead seals to render the electrodes proof against leakage, can

be operated continuously with no variation in the high intensity of

the cadmium lines and appears to have an indefinite life. COLORIM ETRY.

This section is concerned with the measurement of the physical

properties which serve to specify the sensation called " color." As

the ordinary stimulus of color sensation is light, colorimetry deals

with measurements relating to light, and defines the color of a sub- stance as the color produced by the light transmitted or reflected by

the substance under prescribed conditions. The color of light is determined by its frequencies or wave lengths, the relative intensities of the component frequencies and their total intensity.

The investigations of the colorimetry section are closely related

to those of other sections of the Bureau, such as photometry, radiometry, and photography, and its methods find practical application in

chemistry, ceramics, pyrometry, and in the testing of textiles, paper,

paints, dyes, oils, and other materials, and in the specifications and

regulations governing the use of railway and other signals and eye- protective glasses.

General Summary of the Year's Progress in Colorimetry.

Material progress of a satisfactory nature has been made in three

major or general problems in colorimetry and the measurement of

transmission and reflection of radiant power, namely : The standardization of the nomenclature of chromatics and colorimetry ; improvement of methods and standardization of routine practice in spec- trophotometry and in ultra-violet and short wave-length infra-red

radiometry; and in the application of rotatory dispersion to photometry, colorimetry, and pyrometry.

Many special investigations have been conducted during the year

and as a result a great deal of valuable data has been secured. In

other cases a small amount of progress only has been possible, due
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. Icl

to the large amount of work on hand and for other reasons. Numerous publications have been issued from the section and will be found

listed at the end of the colorimetry report.

The various investigations conducted during the year are described in greater detail in the following paragraphs

:

Present Status of the Color-Standards Investigation.

The essential feature of the present status of the color-standards

investigation may be described as follows : Apparatus for the determination of spectral transmissive and

reflective properties of materials by visual, photographic, photoelectric and thermoelectric methods is installed and in active use in

various researches and tests. Such measurements constitute the

essential physical basis of color specification. Care has been taken

to design apparatus and formulate methods of observation and computation so as to convenience and expedite the conduct of this work;

and every effort is made to keep these permanent installations always

in condition to make measurements on short notice. The work of

the past year has shown a very gratifying degree of agreement between determinations by different methods.

Notwithstanding the improvements that have been made, the

methods just mentioned leave much to be desired from the point

of view of rapidity of work; and a great deal of attention is now

being given to the development of improvements to economize time

of observation and eliminate tedious computations.

Considering the magnitude and complexity of the task, the progress on development and establishment of standard nomenclature

is satisfactory and gratifying. From the very nature of the case, this is a subject which can not be brought to a definite conclusion

for a number of years. It must go hand-in-hand with new experimental work and the crystallization of ideas on the subject among

all interested in it. The development and practical establishment of rotatory dis- persion methods is in the active formative stage. Enough has been

done to show the utility and value of the method but a vast amount

of work remains to be done.

The practical and prompt handling of the technologic problems

of color grading materials proposed to the Bureau by the industries

is at present a most difficult matter because of the lack of fundamental data and standards. More effort should be directed to the

solution of general fundamental problems even if it involve the

apparent neglect of specific problems, because the solution of particular problems will follow easily when the fundamental knowledge

is at hand.

Without attempting to outline the research which should be undertaken to extend over a term of years, it may be stated that the most

pressing fundamental problems are:

1. The determination, definition, and establishment of recognized

standards of average daylight and " normal gray light."

2. The quantitative correlation of color (sensation) and the spectral distribution of radiant power (stimulus). These should be re- garded as the major problems of the coming year.
132 REPORT OF DIRECTOR OE BUREAU OE STANDARDS.

The impossibility of obtaining suitable optical instruments continues to be a most serious handicap to the general practice of colorimetry outside of the Bureau. It is useless to prescribe measurements

without the instruments necessary to make them. The manufacture

and supply of instruments now well standardized as well as the

design of new ones is a most urgent need.

The education of the public interested in colorimetry from a practical point of view is an urgent need which is being partially

met by occasional lectures, much correspondence, and by publications; but it is impossible to undertake this work as rapidly or ex- tensively as is desirable.

Specific subjects which have made considerable progress during

the year are reported upon in detail in the following paragraphs

:

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. The formulation and standardization of

these matters has been carried on by the colorimetric section for

the last two years, but it is necessary that general agreement be

reached with all concerned. Action toward this end was taken by

the Optical Society of America in January, 1919, a committee being

formed with the chief of the Bureau's colorimetric section as chair- man.A comprehensive preliminary draft of a report on nomenclature

and standards of colorimetry has been prepared and submitted to the Optical Society of America. This draft comprises about 50

typewritten pages and 6 tables. The report presents for the critical consideration of other experts

the system of nomenclature in course of development and in cur- rent use in colorimetric work at the Bureau of Standards. Particular detailed attention is given to names and symbols involved in

spectral transmission and quantities related to it. It is not considered advisable to print this report at the present

time, but complete copies are being supplied to experts on this subject with requests for criticism and suggestions for revision. Two

complete record copies have been deposited in the Bureau of Standards' library and may be consulted there or borrowed by mail.

Spectrophotometric Methods.

As has been repeatedly emphasized in previous reports, the physical basis of colorimetry is spectrophotometry. The visual, photoelectric, and photographic methods, mentioned in last year's report,

page 128, have been used continually throughout the year, and have

proved very satisfactory.

Certain changes and improvements in the visual and photographic

apparatus are described very briefly in Bureau of Standards Technologic Paper No. 148 on the transmission of colored glasses. Still further improA^ements in these methods are contemplated. When

they have been finished and thoroughly tested papers will be issued

completely describing these methods.

A detailed description of the photoelectric method has been published as Bureau of Standards Scientific Paper Xo. 319. The null
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 133

method used has made it possible to eliminate many errors common

to photoelectric deflection methods. The only variable in the process

of making a determination of the transmission at any wave length

is the accurately measurable distance of a small light source from

the slit of the spectrometer. Measurements of spectral transmission can be made from 380 millimicrons in the extreme violet to at least 650 millimicrons in the red. A modification of the method has also enabled measurements of

diffuse spectral reflection, relative to a standard like magnesium

carbonate, to be made over nearly the same range of wave lengths,

but with somewhat less accuracy. Measurements of relative specular

reflection have also been made. In addition, the method is applicable to the measurement of the relative radiant power of two sources and to the measurement of fluorescence, and could be extended into

the ultra-violet if quartz parts were used instead of glass.

A thermopile and galvanometer have been installed with the photoelectric apparatus in such a way that spectral transmissions may

now be measured either photoelectrically (null method, two photoelectric cells and electrometer) or thermoelectrically (deflection

method, themopile, and galvanometer). The change from one method to the other can be made in a moment's time.

The large Hilger constant-deviation spectrometer glass prisms

makes this thermoelectric method very suitable for the work of the

colorimetry section. The method agrees well with the visual method

from 600 to 700 millimicrons, and it not only extends the trans- mission measurements from TOO to 800 millimicrons, a region of

considerable importance in certain colorimetric work and very difficult of accurate measurement, but it makes possible the trans- mission -measurements to about 1,400 millimicrons, where 1 centimeter of water becomes practically opaque. Thus it is very suitable

for the testing of dyes in solution. The special value over the range

from GOO to 1,400 millimicrons is due to the fact that a much nar- rower slit, and therefore, a much purer spectrum, can be used than

is obtained over this range with the usual infra-red spectrometer,

which is intended primarily for the work at wave lengths longer

than 1,000 millimicrons.

Measurements are being made of spectral transmission of high

precision over the complete range from 220 to 1,400 millimicrons.

The approximate range of the photographic method is from 220

to 500 millimicrons; the photoelectric, 380 to 650; the visual, 436 to 720; the thermoelectric, 600 to 1,400 millimicrons. This overlapping

has enabled a more thorough comparison of methods to be made

than has probably ever been, done before, and has resulted in the

detection and elimination of various errors which would otherwise

have escaped notice. The excellent agreements between these dif- ferent methods, as used during the past years, will be extensively

illustrated in a forthcoming paper on the spectral transmissivity

of dyes in solution.

The visual method is the only one at present available which

measures spectral reflection in the proper way, i. e., the specimens

are diffusely illuminated and the reflection measured at right angles

to the surfaces. At present magnesium carbonate or oxide is taken

for standard white as a comparison surface. The range and ac-
curacy for this method are precisely- the same as in measuring

spectral transmission. The photoelectric method as so far used is reliable only for perfectly diffusing surfaces. The agreement obtained between the visual and photoelectric methods for surfaces

approximating to this condition is very good. Such agreements are extensively illustrated in a Bureau of Standards Technologic Paper

(now in press) on the Munsell color system. A few measurements

of reflection have been made with the photographic apparatus using

the intense light from the quartz-mercury arc. These were only

approximate, however, because of the discontinuous spectrum of

this source. Nevertheless, the agreement with the photoelectric

method was good. Plans are now being made for obtaining diffuse

illumination from the underwater spark which gives the continu- ous ultra-violet spectrum used in transmission measurements and

is in a manner analogous to that now used for visual work. The

thermoelectric method method has not so far been adapted to re- flection measurements over the range 600 to 1,400 millimicrons. This

would be possible only with special apparatus of the highest sensibility.

The new illumination apparatus mentioned in last year's report

has been thoroughly tested in respect to the conformity of trans- mission measurements with Lambert's experimental law for dif- ferent thicknesses of liquids. These measurements were found to be

in accord with the law for thicknesses from 1 to 100 millimeters.

Improvements in the cooling and ventilation of this apparatus have

been installed, and the thermostats mentioned in last year's report were placed in service about August, 1919.

A direct-reading instrument based on the principle of variation

of thickness, mentioned as in course of design in the previous report,

has been constructed in the Bureau's instrument shop and has satis- factorily passed its preliminary laboratory tests. It was exhibited

and demonstrated at the convention of the American Oil Chemists'

Society, New Orleans, May 11, 1920. The specification of the

essential features of its design is being published in the chemists'

section of the Cotton Oil Press (July or August, 1920). It is expected that a detailed illustrated description will be published by

the Bureau during the coming year. The Application of Rotatory Dispersion to Colorimetry, Photometry,

and Pyrometry.

For about eight years studies in the application of rotatory-dispersion methods to colorimity and related subjects have been in progress

at the Bureau. The method proves to be of fundamental practical

importance. In order that it may be more generally understood and

put to practical use a series of papers relating to it are being pre- pared for publication. A general paper outlining the subject and

giving a resume of past work was presented to the Optical Society

of America, New York, February 27, 1920, and will be published in

the journal of that society.

Extensive tables and graphs for computation to facilitate the

application of this method are being prepared. Some of these are now in use at the Bureau, and it is hoped to publish them later for

the use of others.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 135

A New Study of the Leuccscope.

The leucoscope is an instrument developed and used by Helmholtz

and his pupils between 1878 and 1888 primarily for the study of

vision. Since that time practically nothing- has been done 'with it. Recent experiments at the Bureau have shown the applicability of

the instrument to pyrometry, and new laws of the instrument have

been discovered relating its readings to temperature and spectral

energy distribution in a light source or furnace. These data were communicated to the Optical Society of America. New York, Feb- . ruary 27, 1920, and will be published in the journal of that society.

As the year closes the reduction of the data from these experiments

promises to yield important information on the correlation of color

(sensation) with the spectral distribution of energy (stimulus).

Investigation of the Spectral Transmissivity of Dyes.

The present pronounced interest in the development of the dyestuff industry has emphasized the need of accurate and reliable data on the properties of the dyes. Dyes are characterized by their re- markable selective absorption for light of different frequencies

(color), i. e., light of certain colors is freely transmitted by the dye,

while that of other colors is strongly absorbed. Also radiant energy

in the infra-red and ultra-violet is affected in the same selective way.

For purposes of identification and analysis of elves reliable and

accurate data on the transmissivity for a wide range of frequencies

is of recognized importance, but little such data are available. During several years past the Bureau has been making extensive and

elaborate preparation for a systematic investigation to obtain such

data. This preliminary work is now finished and the investigation

proper in cooperation with the Bureau of Chemistry of the Agricultural Department has been in progress for the past year. The

Bureau of Chemistry is providing known analyzed samples and the

Bureau of Standards is determining spectral transmissivities at various temperatures and concentrations throughout the visible and

into the ultra-violet and infra-red. The dyes just at present in course of investigation are the " permitted food colors." Others will

be taken up as rapidly as the work can be done. It is expected that

the whole investigation will extend over a period of years more or

less continuously, but partial reports will be issued from time to time as the data are obtained. These data will be in the form of

tables and curves giving the specific transmissivities over a wide

range of frequencies in a form convenient for the practical purposes

of the dye anatyst as well as for theoretical discussion of the nature

of absorption and its relation to constitution. A paper is now in

preparation which will describe in detail the methods and apparatus

used and present the data on the seven food colors in tabular graphical form.

No provision has been made for continuing this investigation on a

scale at all commensurate with its magnitude and importance. Until

such provisionals made, it will be necessary to suspend this work.

The large amount of work which has been done was carried on at the expense of neglecting other investigations which, on account of

their more fundamental and general nature, should be given precedence, and which must be actively resumed.
136 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

The Commercial Color Grading of Material in Which Color is an

Important Property.

.b rom 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 ; it is of the most vital importance

in many industries. 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 are, therefore, divided between fundamental research and its application.

The materials which it is desired to grade by color in commerce

are almost innumerable, including 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 practically dealing with

these problems general principles nearfy always have to be specialized, and each problem requires individual treatment. Up to the

present, the Bui'eau has been able to give very few of these problems

adequate attention. Problems of this kind on which material progress has been made are noted in the following paragraphs.

Vegetable Oils.—The original investigation of the color of cot- ton-seed oil has been extended to other similar vegetable oils (peanut,

soya bean, sesame, and coconut.) During the year a vast amount of

experimental data on the spectral transmissivity and color of these

oils has been obtained. Important relations between the spectral

transmissivity and the color on the Lovibond scale have been dis- covered. The Bureau's recommendation that these oils be graded in

terms of their transmissivity for .definite wave lengths is still adhered to, but it has been found desirable to modify the recommendation in regard to the particular wave lengths selected for this purpose. A report on this subject was presented to the American Oil Chemists' Society (formerly Society of Cotton Products Analysts) Convention, New Orleans, May 11, 1920. An abstract of this report is being published in the chemists' section of the Cotton Oil Press (July

or August, 1920). A Bureau of Standards Technologic Paper is in course of preparation.

Paints, Pigments, and Inks.—A great deal of data on the spectral

reflection of paints, pigments, and inks has been obtained. The

spectral reflections of pigments submitted for test by DuPont de

Xemours & Co. have been determined, and a report is being made

to them. (See also reports on "Camouflage Paints" and "ThreeColor Process Inks" below.)

Dyed Silks.—The spectral reflections of a number of dyed silks have been determined for Cheney Bros. Sugar Solutions.—With the cooperation of the polarimetry section,

the transmissivities of a large amount of sugar for particular wave

lengths have been determined, and it appears that this method will

be satisfactory for the routine grading of sugar solutions.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 137'

Investigation of Camouflage Paints.

The Bureau has determined the spectral reflections of paints used

in camouflage pictures. A report has been prepared and it is ex- pected to publish it later. Standardization of Three-Color Process Inks and Filters. At the request of the American Institute of Graphic Arts, the' spectral reflection of 40 different samples of three-color process printing inks, red, yellow, and blue, each on coated and dull finished paper,, has been measured and a report issued. In this report were in- cluded actual samples of all the inks as well as the spectral reflection curves. In the report were also given the spectral transmission, curves of the red, green, and blue filters used in this kind of printing.

By invitation the chief of the Bureau's colorimetry section lectured on this subject before the American Institute of Graphic Arts, New

fork, February, 1920. Investigation of the Lovibond Color Scale as Used in Grading Vegetable Oils.

A very thorough investigation of the Lovibond glasses used in

color grading A~e getable oils is in course and nearly completed. This

work comprises : (a) The determination of the spectral transmission

of the combinations of yellow and red glasses; (b) calibration of

the glasses by rotatory dispersion colorimetry (Arons chromoscope ) ; (c) calibration of the glasses by " leucoscope " readings;

(d) reduction of the spectral transmission data to luminosity and

its correlation with the Lovibond grade and the above calibrations.

The investigation confirms the previously observed irregularities

in the Lovibond scale. A partial report was made to the American Oil Chemists' Society,

May 11, 1920, and a Bureau of Standards Technologic Paper on this, subject is in course of preparation.

The Correlation of Color with Its Stimulus.

The general formulation of the conditions which must be satisfied by two different spectral distributions of energy (stimulus) in order

that they ma}7 excite the same color (sensation) is a problem of

fundamental importance in colorimetry.' Some progress has been

made in its solution. We find in all cases so far tested, including a wide variety of energy distributions : // two different spectral dis- tributions of energy excite the same color, the wave lengths of the

centers of gravity of their luminosity curves are coincident. Other

conditions are in course of formulation as the year closes. Investigation of Eye-Protective Glasses.

Work of this nature, during the past year, has been mainly routine

testing performed at the request of various commercial concerns or

of other Government departments. These tests have consisted either

in the measurement of spectral transmission of miscellaneous glasses

in the visible or ultra-violet, as was done in Bureau of Standards

Technologic Paper No. 119 (abstract given in last year's report, p. 133), or in the measurement of various types of welding lenses to

see if they meet the specifications for such lenses given in the Tenta-
138 REPORT OF DIRECTOR OE BUREAU OE STANDARDS.

th'e National Safety Code for the Protection of the Head and Eyes

of Industrial Workers, issued at the Bureau of Standards.

As shown by some of these tests, it is now possible to obtain welding lenses, suitable for the different types of work, which absorb or

reflect all the harmful ultra-violet rays and all but a very small per

cent of the infra-red or heat rays. The Bureau does not attempt to specify what is the proper amount of total light transmission for the

various welding processes, as such information can be obtained only

in actual trial by welding experts.

The Ultra-Violet and Visible Transmission of Colored Glasses.

The transmissions for the visible and ultra-violet of over 50 dif- ferent kinds of colored glass, not classed especially as eye-protective,

have been published (Bureau of Standards Technologic Paper No.

148). An abstract of this paper Avas given in last year's report,

page 132. 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, selective ray filters, and monochromatic light filters for use with the mercury, helium, and hydrogen lamps.

Colorimetric and Related Tests. Formal test reports were made on spectral transmission of various

glasses, inorganic salt solutions, vegetable oils, photosensitizing dyes,

and colored gelatine filters; tests were also made on the color and

spectral reflection of standard color cards, paints, and silks, on the

relative radiant powers of various lamps, and on the transparency

of 17 envelope windows. Thirty-one tests were reported from this

section during the year. About 200 separate specimens or samples were included in these tests. The applicants for these tests included the following: Navy Department (various bureaus), Post Office Department, Pennsylvania

Railroad Co., Cheney Bros, (silk dyers), Philip Euxton (Inc.) (ink

makers), various dealers in eyeprotective glasses, and various oil refiners and chemists.

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 by personal conference with visitors. About 140 letters of information were sent and about 50 such visitors were given oral

information.

REFRACTOMETRY AND OPTICAL INSTRUMENTS.

In addition to the more or less routine tests of refractive indices

of optical materials and on the performance of optical instruments,

special attention has been given during the past year to a combined

laboratory and field test of short base range finders; to an investigation of the cause of the formation of films on the optical parts of

observing instruments and the remedy; to an investigation of the

effect of variable contrast in the charts used for testing the resolving

power of optical instruments ; and to the standardization of design

of the optical parts of laboratory telescopes.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 139

^Range-Finder Investigations.

In cooperation with the Ordnance Department, U. S. Army, the

Bureau conducted a series of tests in its own laboratories and field tests at the Artillery School of Fire, Fort Sill, Okla., on 20 shortbase, self-contained, optical range finders of various types. The

main objects of this investigation were to determine (1) the true

value of the range finder as a fire-control instrument, by testing

its accuracy on different types of targets under different conditions

of service; (2) an adequate acceptance test at the factory; (3) the

relation between the accuracy of the instrument and its optical and

mechanical design, with a viev\T to improving the performance of

instruments of this class. The data obtained furnish knowledge as to the manner in which

the probable eiTor may be expected to vary with range when the

infinity adjustment is correct and also when it is incorrect, for each

instrument, and with the different types of targets. This gives the

probable error due to accidental causes, including the limitation

of the observer's eye. Up to the present there has been little information regarding this outside the statement of the manufacturer

as to the least error to be expected under the most favorable conditions, and the assertion that under usual conditions the error may

he assumed to be twice the most favorable value. The desirability of a scientific determination of the errors actually occurring in practice

with targets of different types is obvious.

By properly interpreting the data the part of the actual error which is ascribable to a faulty infinity adjustment is determined.

This is of special importance, as no other field tests appear to have

been made in which these errors are separated from the others, al- though they arise from entirely different causes and must be separately remedied.

A preliminary survey of the data gathered indicates that under

usual service conditions an incorrect infinity adjustment, introducing an error amounting to as much as 10 to 20 per cent of the range,

may result from the use of adjustment laths which have not been

properly fitted to that particular instrument. It has furthermore

been concluded that the range finder is so easily thrown out of adjustment by shocks, unequal heating, etc., that the common practice in

the Field Artillery, of allowing range finders to be trucked around

and used in ranging for days without testing the adjustment,

should be suppressed.

From the records of these tests interesting and valuable information will be gleaned on such questions as the improvement in the

ability of the operator with practice, the effect of decreasing the

brightness of the image in either one or both parts of the field, the

accuracy of certain types of internal adjusters, the effect of temperature changes, the change in coincidence arising from the in- troduction of light filters, and the variations in the instrument from

day to day.

" Filming " in Optical Instruments.

Many optical instruments are rendered unserviceable by the formation of deposits upon the reticles and other optical surfaces. At

the request of the Ordnance Department of the Army an investigation
140 . REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

of the cause of these deposits ancl means of avoiding- them was undertaken. The evaporation of the lubricant was found to be contributory

to at least part of the filming, so a suitable lubricant was sought.

The following information was gained from the tests: (1) Vaseline

which has been boiled a long time is the best available lubricant for

optical instruments; (2) Where more body is desired, a solution of

pure rubber in vaseline ma}7 be used; (3) The presence of water is necessary in the formation of films, therefore absolute dryness is desirable. If this be impossible, good ventilation through dust filters of screens or cotton pads should be provided.

Triangulation Cameras.

A set of triangulation cameras for use in checking the fire of big

guns on board battleships was redesigned and constructed in the

Bureau's shops for the IT. S. Navy. These were designed to expose

the film, wind it, and set the shutter for the next exposure automatically on pressing a button.

Lens Tables.

Tables giving the dimensions of the lens blanks along with the

constants arid tolerances of the glass for various types and sizes of

lenses are in process of formulation, of which the following have

been completed:

For 26 sizes ordinary f/5 achromatic lenses, with data for their component elements. For 31 ditto for telescope objectives. For 25 sizes f/5 simple positive lenses. For 25 sizes " spectacle " lenses. For 21 sizes condenser lenses. Test Chart for Photographic Lenses.

A method for testing a photographic lens by photographing a

special chart has been developed, and a specially mounted camera

constructed for this purpose. One of the advantages is the saving

in wall space, a single line of charts 5 feet from the floor, together

with a device for rotating the camera about its optical axis, serving

to give a full test field. Resolution Chart with Variable Contrast.

For testing the resolving power of telescopes a resolution chart

with a series of illuminated lines against a dark background is commonly used. While this gives a fair comparison for different in- struments, it does not necessarily indicate what the resolving power

would be in actual use, because this is known to vary with the amount

of contrast between the lines resolved and the surrounding field. A chart with variable contrast has been devised with the object of

studying the variation in resolving power with contrast, with the

special application in view of obtaining a more sensitive test than

is available at present, for the effect of striae in optical glass.

Specifications for Sextants,

After extensive conferences with both makers ancl users of navigation instruments, specifications incorporating standard practice in

design and performance of sextants have been prepared. Certifi- cates issued for marine sextants will be based on these specifications.
'REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 141

Airplane Mapping Cameras.

Preliminary to the mapping of Santo Domingo and Haiti by the

United States Geological Survey their camera was given a thorough

optical investigation and its various mechanical devices tested. For the Navy Air Service a dozen air-mapping cameras were given

the customary optical tests, and fitted with attachments for locating

the optical center of the photographs.

The Optical Constants and Chemical Composition of Optical Glass.

Collaboration with the optical glass section in determining the

various optical constants of the glass produced by that section was

continued during the past year. In the production of new types of optical glass it is not sufficient to know the composition of the batch from which the glass is melted,

but the chemical composition of the finished product must also be

known. In cooperation with the chemistry division a preliminary

investigation of the composition of several kinds of optical glass was

undertaken. This work, which gave promise of success, has of necessity been postponed for the present.

Tests for the Purpose of Drawing Up Specifications.

At the request of the Army and Navy Bureaus of Ordnance complete measurements of the optical systems of various instruments were made for the purpose of writing specifications for them. Among

these instruments may be mentioned panoramic sights, telescope

sights for heavy artillery, tank sights, and officer of the deck spyglasses.

Design of an Oscillograph Condenser System.

A condenser sj^stem, free from spherical aberration, for illuminating an oscillograph was computed for the electrical division.

Information Given.

Many requests from inventors were received for tests, calculations

and suggestions in connection with various devices and schemes of an optical nature. Among those examined were a sextant for aerial

observation, designed to measure the horizontal angle between objects at different elevations; a 6-inch base range finder; a stereoscopic

gun sight ; a machine-gun sight for night firing ; an airplane position

finder ; a moving prism motion-picture camera ; and a revolving mirror camera for photographing 1,000 pictures a second.

Information in letters, circulars, and drawings was sent out on re- quest to Government agencies, manufacturers, and private individuals on such subjects as the silvering of mirrors, formulas for lenses and

mirrors of special form, frosting of glass, index of refraction of vari- ous substances, the operation of motion-picture machines, the manufacture and testing of optical glass, the cementing of lenses, and the

testing of photographic lenses. Summary of Tests. During the year 239 binoculars, 100 photographic lenses, 19 tele- scopes, 10 refractometers, and 54 samples of optical glass were given

the customary tests, and tests of a miscellaneous nature ran the total

up to 513.
142 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

RADIO METRY.

In the general subject of radiometry some attention was given to the transmissive and reflective properties of materials. In response

to inquiries an examination was made of the infra-red transmission

of nitrocellulose submitted under the trade names of " celluloid." " pyralin," and " viscoloid," which substances were found to have

the same transmissive properties.

The reflective properties of metal on glass mirrors was investigated. An examination was made also of the transmissive properties

of new eye-protective glasses.

The general investigation of the effect of thermal radiation upon

the electrical conductivity of materials was practically completed

during the year, though several subsidiary questions remain for

further inquiry.

Glasses for Protecting the Eyes from Injurious Radiations.

In view of the fact that apprehension was expressed that in the

proposed safety code for eye protection, the specifications were so stringent that it might give one manufacturer a monopoly on the

prochiction of glass for protecting the eyes from injurious radiations, a series of experiments was made showing that colored glass

easily obtained in commerce and used in the combination (1) red and

green; (2) reel and cobalt blue; or (3) brown and cobalt blue will

meet the requirements for protection against ultra-violet and infrared rays. Constants of Radiation of a Uniformly Heated Inclosure.

The determination of the constants of radiation is beset with many

difficulties owing to the fact that many of the subsidiar}*- constants entering this determination are undergoing revision. Among these

factors are the temperature scale, the refractive indices of the materials composing the prisms used, and new determinations of the

effect of atmospheric absorption. As a result of these changes in the

contributory data most of the old determinations of the radiation constants are subject to repeated revision.

During the past year therefore further consideration was given to

the Bureau's determination of the constant of total radiation mentioned in the annual report of 1916. The conclusion arrived at is that the value of <y=5.75XlO"12 watt-cm-2

, cleg-4 previously published, remains unchanged. After making corrections for atmospheric absorption, etc., it is found that the average of all the

reliable determinations by other observers is a=5.73 to 5.74X10-12. Further attention was also given to this Bureau's determination

of the constant of spectral radiation mentioned in the previous

report. It was found that the temperature coefficient had not been

applied to the refractive index of the fluorite prism for the yellow

helium line, although it had been applied to the infra-red refractive

indices. Making this correction reduces the previously published

value (c2 =14,369) of the constant of spectral radiation by 0.3 to 0.4 per cent, giving an average value of c2 =14,318. Furthermore, after

correcting the data of some of the other experimenters the average

value of all observers is c2 =14,320 micron degrees.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 143

Methods of Computing and Intercomparing Radiation Data. Under this title a paper was published giving quick methods for

computing spectral energy curves, using the Planck formula. In

this a chart serves the purpose of intercomparison of thermal radiation constants with similar data obtained indirectly from ionization

potential, photoelectric, and X-ray measurements. From an intercomparison of the data obtained by these methods, it appears that

the value of Planck's constant h, computed from radiometric data,

•agrees very closely with that obtained by more direct measurement.

From this intercomparison it further appears that to a close degree

of approximation we have

c2 =ll,320 micron cleg., cr=5.72XlO~5 erg. cm-2, deg~4

., and A=6.55X

10~27 erg. Measurements of the Compotent Radiations from the Sun and from

a Quartz Mercury Vapor Lamp.

This investigation involved the construction of a spectropj'rheliometer consisting of a quartz lens and prism spectroradiometer on a simple equatorial mounting. An important part of the

apparatus is a cylindrical quartz lens which enables the solar image

to be focused on the spectrometer slit and the device to be operated

by hand. The results obtained with this instrument show that there

is no marked difference in the total amount of ultra violet radiation

from these two sources. However, the spectral quality of the ultra

violet radiation is very different, the ultra violet spectrum of the sun terminating at a wave length of 0.3(1, ([a=0.0Q1 mm.), Avhile that of the quartz lamp has 20 per cent of its ultra violet component

radiation at wave lengths less than 0.3(1.. Reflective Properties of Metals and Alloys.

In collaboration with the Metallurgical Division of this Bureau

alloys of aluminum with magnesium and with zinc were prepared

and their reflecting power determined. Contrary to the reports of

previous investigators, these alloys were found to tarnish and hence

are unsuitable where permanency is of prime importance.

In response to inquiries for data thereon an examination was made

of the reflective properties of monel metal ; also of stellite and zinc.

The latter is unique in having a deep minimum of reflectivity at followed by an unusual high reflectivity beyond 2(i,. The reflec- tivity curve of monel metal differs but little from that of pure nickel.

Photo-electrical Investigations.

An examination was made of the spectrophoto-electrical sensitivity

of Case's thalofide cell, which is a laboratory preparation of thalliumoxy-sulfid. This substance has a wide, complex band of photo-electrical sensitivity extending from the visible spectrum to 1.2jjt, in the

infra-red. There is a complex maximum at l[i. A comparison was made of the light sensitivity of the eye and of

photo-electric cells, and the conclusion was drawn that there is nothing to indicate a similarity in the response of these two types of lightsensitive media.

From the results of various photoelectrical investigations, made

principally at this Bureau, it is possible to formulate a few general
characteristics of spectrophotoelectrical sensitivity in solids. Among

other things it appears that the photoelectrical response, to an equal

energy spectrum, is fairly uniform throughout the visible spectrum

terminating in a band or bands of high sensitivity in the near

infra-red. Increasing the intensity of the radiation stimulus shifts

the maximum of the photoelectric sensitivity curve toward the

longer wave lengths. Decreasing the temperature of the substance

greatly increases the intrinsic photoelectrical sensitivity throughout

the whole spectrum and shifts the maximum of the sensitivity curve

"toward the shorter wave lengths.

A sample of molybdenite was found which has a region of photoelectrical sensitivity, the reaction of which is unique in being positive or negative depending upon the wave length of the radiation

stimulus as well as upon the magnitude and direction of the current through the crystal. This discovery necessitated an investigation

of the photoelectrical reaction as affected by the temperature, the

intensity and wave length of the radiation stimulus, etc., and a

correlation of these data with the meager data previously published on negative photoelectrical reactions in other substances.

Information Furnished on Radiometric Subjects, Conferences, Tests. In reply to specific requests therefor, information was given on

various radiometric questions such as for example the measurement

of radiation in absolute value; transmissive and reflective properties of materials to be used for specific purposes, also methods of

measurement of the same; source of ultra-violet light, methods of

measurement and usefulness in sterilization; the radiation laws and

their correctness; energy lost from fine wires; radiometers and

methods of measurement of the emissivity of material such as molten glass; eye protective glasses, and substitutes for special

glasses.

In addition to tests and replies to inquiries personal instruction was given to a party who was preparing to study the effect of radiation upon plant growth; also a representative of a manufacturing

establishment was instructed in the minute details of construction

of radiometric instruments.

Publications on Radiometry.

The following publications were issued during the past fiscal year

:

Scientific Papers, No. 338, Some Optical and Photoelectrical Properties of Molybdenite; No. 342, Reflecting Power of Stellite and

Dacquered Silver; No. 344, Spectral Photoelectric Sensitivity of

Silver Sulphide and Several Other Substances; No. 357, Constants

of Radiation of a Uniformly Pleated Inclosure ; No. 360, Methods

for Computing and Intercomparing Eadiation Data; No. 362, Distribution of Energy in the Spectrum of an Acetylene Flame; No.

363, Preparation and Reflective Properties of Some Alloys of Aluminum with Magnesium and with Zinc; No. 378, A New Spectropyrheliometer and Measurements of the Component Radiations from

the Sun and from a Quartz Mercury Vapor Lamp ; No. 379, Reflect- ing Power of Monel Metal, Stellite, and Zinc ; No. 380, Spectrophotoelectrical Sensitivity of Thaloficle.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 145

PHOTOGRAPHIC TECHNOLOGY.

Sensitometry.

A new instrument for measuring the filter factors of color sensi- tive materials has been designed and constructed. This instrument

is constructed on the principle of a photometer, using a single source

of light. Two beams of light, one from each side of the lamp, are

reflected in such a manner that both of them are brought side by

side to the plate to be tested. Just in front of the plate, and placed

so that both beams pass through it, is the compensating filter which

is used to reduce the spectral distribution of energy to that of average noon sunlight. These lamps and filter combinations when used under

certain particular conditions have been adopted by this Bureau as a standard source of energy for sensitometry.

In the path of one of the beams is placed the filter to be tested

with the plate. The lamp is moved from zero to various positions

and an exposure given at each setting. ^Yhen the lamp is moved one

of the beams is lengthened and the other shortened by an equal

amount. After these plates have been developed the difference in

densities are measured by means of a polarization photometer.

These density differences are plotted against the scale distances or

settings of the lamp. Some of the densities will be larger on the side

of the instrument without the filter (marked -j-) and the others will

be larger on the side with the filter (marked — ). Those having the

density larger on the filter side are plotted above the scale and the

others are plotted below the scale (scale=0). A line is drawn

through the points, and where it intersects the scale is the place where

the two beams are of equal photographic intensity for that particular

plate and filter. From the scale distance, which is the amount by

which one of the beams of light is lengthened and the other shortened, to obtain this match or photographic equality, and knowing

the total path of both beams, is calculated the filter factor, using the

inverse-square law.

During the past year the characteristics of 86 brands of Americanmade plates and films have been investigated. These light-sensitive

materials were tested with the specially designed sensitometer mentioned in the last annual report. In most cases nine samples were

cut from the plates and films and exposed in the sensitometer. _ These

nine test pieces were exposed in groups of three, making a total of

three complete tests on each brand of material. In each test the three

exposed samples were developed for different lengths of time, so that

the development velocity or the growth of contrast could be determined. In all cases the test specimens were developed in a thermostated developing bath. These tests gave the following characteristics in numerical values : Speed, contrast, and scale or range of

light intensities that the material will record. These tests, including

a number of special ones, required more than 8,000 density measurements.

The color-sensitive qualities were also determined by two methods

:

First, the plates and films were exposed in a specially designed

spectrograph. This instrument gives in graphical form the relative

sensitivity to the various colors of the spectrum. Second, the filter factors were obtained with the instrument mentioned above. Filter

10613—20 10
146 REPORT OF DIRECTOR OE BUREAU OF STANDARDS.

factors are the numbers by which an exposure without a filter must

be multiplied to obtain the same photographic effect when using that

particular filter. Light filters used in photography are of all colors

and of various intensities of color, and the filter factors not only

vary considerably with the color filter used, but also with the brand

of plate or film with which they are used.

In addition, a test of the resolving power of the plates and films is being conducted.

All of these data are being collected to form an atlas of negative

emulsions, but at the present time it is available only to the Government departments.

Photostat Machine Paper.

Samples of several brands of photographic paper for use in the

photostat machine were tested for the War Department. These tests showed the comparative speed, contrast, color sensitivity, and the

filter factors. The developers for use with the above papers were

tested for velocity of development.

Large Camera and Stand.

A 30 by 30 inch special process camera and stand, including copy

holder, was designed for the Coast and Geodetic Survey. This equipment is now being constructed.

Camera for Bomb Trajectory.

Assistance was given the aircraft armament section of the War

Department in solving a photographic problem in connection with

airplane bomb trajectory.

INTERFEROMETRY.

In addition to the testing of several thousand precision end gauges,

the principle of interference of light waves has been applied in

measuring the thermal expansion of glasses with special reference to

their annealing temperatures; the change in dimensions of dental

materials on setting, under pressure, with temperature, etc. ; the

change in length of gauge materials with time and treatment, in ordej* to obtain invariable gauges ; and the change in diameter with temperature of " sealing in " wires.

Thermal Expansion of Glass.

This imr estigation Avas undertaken in connection with the Bureau's

production of optical glass. A large number of optical glasses, plate

glass, chemical glass, and commercial tubing were investigated.

Length measurements were made in the temperature range between

20° and 650° C. All the glasses passed through a critical expansion

region in which the expansion rate was two to seven times the normal

value. This critical region, which for any one glass does not exceed

40°, was found for some kinds as low as 400° and with others as high as 575°. About 75° above the critical region the glass softens

and contracts. Physical Properties of Dental Materials.

This investigation was undertaken by the weights and measures and the optics divisions in collaboration, at a request from the
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 147

Surgeon General's Office of the War Department. The combined

object of the investigation was to draw up specifications for filling

materials and to develop methods for testing their different physical

properties. Interference methods were used for measuring all di- mensional changes.

Standardization of Precision Gauges.

End standards or precision gauges are blocks of metal, usually

steel, having two opposite faces plane, parallel and a. specified dis- tance apart. These gauges are used to check micrometers and other

measuring instruments, and also to serve as distance pieces for precise

mechanical work. They are made so nearly perfect that interference

j methods are necessary in calibrating them. The method used requires

standard gauges having the designated length of the one to be tested. Several sets of these standards were calibrated by direct comparison

with the standard light waves. Using these the length of the gauge

submitted for test is quickly determined with an accuracy of a few

millionths of an inch. Over 20,000 of these gauges have been tested

for manufacturers and users during the past year. A description

of the methods will appear shortly in the American Machinist.

Seasoning of Gauge Material.

Foi* the purpose of determining the permanency of gauge materials, during the past two years sample gauges have been selected

from the products of different precision gauge manufacturers and

these measured at given intervals of time. It is found that some

gauges retain their original dimension remarkably well while others

show changes varying from two to fifteen hundred thousandths of an

inch. To find if possible the cause, and to eliminate these changes in

steel, test specimens were made up and subjected to different heat

treatments. A determination of the change in length of these speci- mens with temperature showed that hardened steel shows like glass

a critical region in which its thermal expansivity differs from the

normal value. The first hardening gave a critical region between

260° and 390° C. ; rehardening introduced another critical region near

150° C. These variations in the expansion were removed and a permanent change in length produced by heating the sample above

390°.

Radial Expansion of Fine Wires.

"Wires sealed in glass bulbs which are to be evacuated must have a thermal expansion very close to that of the glass, else the junction will

leak around the wire if the expansion of the wire is too low, or

the glass be cracked if the expansion is too high. The expansion

of such wires was measured between 20° and 375° C, the wires varying from three-tenths to 1 millimeter in diameter and determined with an accuracy of 0.03 microns (1 micron=l/1000 mm.).

Information Given—Publications.

Several representatives of manufacturers of precision gauges were given instruction in the Bureau's methods testing precision

end gauges. The following articles were prepared for publication

:

Physical Properties of Dental Materials in collaboration with the
148 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

thermal expansivity section of this Bureau; Bureau of Standards

Technical Paper, No. 157 ; also in Dental Cosmos, March, 1920

;

Thermal Dilatation of Glass at High Temperatures, Journal Optical

Society of America, May, 1920; and forthcoming Bureau of

Standards Scientific Taper; Calibration and Dimensional Changes

of Precision Gauges in forthcoming number of American Machinist.

SEARCHLIGHT INVESTIGATION.

The searchlight investigation section was organized as such in

September, 1919, to take over the work in this line started by the

colorimetry section. Much of the Avork reported here was started

in that section and part of it entirely completed there. While the ' primary functions of the searchlight section are to carry out, in co- operation Avith the Engineers of the War Department, certain investigations in connection with searchlight illumination, and to per-t form necessary tests on search lamps and search lamp accessories, the* investigation of the power possessed by different light for penetrating the atmosphere under different Aveather conditions, and the

limiting conditions of vision under faint light illumination are of

importance secondary only to that of the performance of the search

lamps themseh^es.

Transmission of the Atmosphere.

A method has been developed and put into operation for obtaining

the relative spectral transmission of the atmosphere under different,

weather conditions. Keports haATe been made to the War and Navy

Departments and a preliminary report is in press. The Diffusion of Light by the Atmosphere.

The loss of light in a beam penetrating large extents of atmosphere is principally from diffusion. This diffused light acts like a

A

Teil between the obserAT ed and the target. A report on this effect has been made to the War and Navy Departments, and an article

is noAv being prepared for publication.

The Contrast Sensibility of the Eye.

The ease with which a target can be seen, when illuminated by a

searchlight, depends upon the contrast in brightness and color between the target and the surrounding atmosphere. It is important

to know the smallest target Adsible under giA'en contrast illumination. Data obtained under simulated Army conditions were compiled and incorporated in (1) a report to the Engineer Corps of the

Army and (2) Bureau of Standards Scientific Paper No. 366. Tests of Searchlight Mirrors.

The most exacting demands of searchlight mirrors are perfection

of form of the reflecting surface, high reflecting power, and durability of both under severe working conditions. The mirrors com- monly used are parabolic glass reflectors silvered on the back surface. Less expensive and more permanent as to fracture are metal mirrors with front surface silvering. They are, however, less durable as to reflecting poAver, hence not so commonly used.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 140

For a general test of the form of the reflecting surface an equipment for the so-called " line test " has been set up and satisfactorily

operated. This test consists in photographing the image formed

by the mirror of a white wall ruled with black cross lines. For exploring the form of the mirror a method has been set up and

satisfactorily operated of photographing after reflection the intersection of several narrow beams incident upon the mirror parallel to

its axis. Certain modifications of this method are being made which

are expected to facilitate the tests. A special reflectometer has been designed for measuring the re- flecting power of a mirror, and some attention given to the development of methods for detecting the existence of mechanical strains in

the glass composing the mirror.

Lacquers and Enamels for Searchlight Mirrors.

The usefulness of metal mirrors depends on the production of a durable protective coating for the front surface silvering, which at the same time does not reduce its reflecting power to an undesirable

extent. In cooperation with the ceramics division, some experiments

have been made on the use of an inorganic enamel for the purpose.

Investigation of this problem in cooperation also with the Army

engineers will be continued.

Photometry of the High Intensity Arcs. Because of flickering and color fluctuations ordinary photometric

measurements on searchlight arcs are very tedious. On the other

hand, because of their high power, direct-energy measurements of

their radiant power are quite feasible. A physical photometer has

been under development for this purpose.

Testing of Search Lamps and Accessories.

Two search lamps with distant electric control and position indicators, one of high power and the other medium, have been received

for test from the Engineer Corps of the Army.

Tests for Lighthouse Service.

The comparative light transmission of plain and reinforced plate

glass for use in the towers was determined for the Bureau of Lighthouses.

Information Given.

This included the uses of high-intensitjr arcs in peace time, general

information on search lamps and searchlight illumination to manufacturers and representatives of foreign countries, and, through the

National Research Council, to a foreign country, information on the

absorption of light by the front-glass windows of search lamps.

Publications and Reports Issued During the Year.

Report on Military Search Lamps and Searchlight Illumination. Report on the Efficiency of Search Lamps.

Report on the Distribution of Light Flux in Searchlight Beam and Some

Considerations on an Ideal Searchlight Beam.

Report on the Relative Spectral Transmission of the Atmosphere ; also issued

as scientific paper (in press).
150 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Report on the Contrast Sensibility of the Eve ; also issued as Scientific- Paper No. 366. Report on the Diffusion of Light in a Searchlight Beam. (This will appear

in a scientific paper in preparation.)

5. CHEMISTRY.

Chemical composition and purity of material; chemical properties and constants, including researches upon methods of analysis, specifications for technical materials, and preparation of pure materials for standardization work for the Government and for industrial and scientific laboratories. PHYSICAL CHEMISTRY.

This section is concerned with the preparation and purification of

materials required in physical measurements of precision—for example, refrigeration materials, calorimetric- samples, materials for

standard cells and for density determinations ; determination of cer- tain physical constants and development of methods for their exact determination.

Through a lamentable accident the chief of the section of physical

chemistry, E. C. McKelvy, met his death in Xovember, 1919. By

reason of his loss and the subsequent resignations of several of those

who served under him, the work of the section was very much delayed,

and during the second half of the fiscal year was restricted essentially to completing as much as possible of the work in hand and

getting the remainder in such shape that it could be looked after by

the one remaining member of the section or held over until additional

men become available.

Refrigeration Materials and Problems.

In continuation of past work involving the determination of important physical constants of refrigerants, the triple point of pure

ammonia, or the temperature at which the solid, liquid, and vapor

are in equilibrium, has been determined. As calculated by a member

of the heat division, this temperature is —77.701: C. with an error not exceeding 0.01°. Besides pure liquid ammonia, carbon dioxide and ethyl chloride were prepared and purified in considerable amounts, enough to meet the needs of the heat division for a year or two in determining the physical constants needed in refrigeration.

Purification of Materials for Special Purposes.

Naphthalene.—Enough naphthalene was prepared for use as a standard for calorimetiw^ to last several years at the present rate of distribution.

After several years of inability to obtain benzoic acid that would

yield a refined product sufficiently free from chlorine to be an irre- proachable standard for calorimetry, a satisfactory article was

finally found and is now being purified and issued.

Methyl Alcohol.—Last year's work on the preparation and purification of methyl alcohol was continued, and the new product will be

tested for density by the division of weights and measures. Atlas of Heterogeneous Equilibria.

The death of the chief of this section terminated all work on the

Atlas of Heterogeneous Equilibria. The large amount of material
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 151

now on file is in such shape that it is readily available for reference

work. It is very desirable that provision be made for the continuation and eventual completion of this work.

Critical Solution Temperature Work.

The study of the critical solution temperatures of carbon disulphide-ethyl alcohol and carbon disulphide-methyl alcohol, discussed

at some length in last year's report, has been completed throughout

the entire range of concentrations.

Glass-to-Metal Joint.

The work referred to a year ago on a glass-to-metal joint was completed. The best joint developed consists of glass platinized and

joined to tinned metal tubes. Such a joint will stand a pressure of

6,000 pounds per square inch.

Glass-to-Glass Joint.

It is often necessary to join together glasses of different kinds.

Direct joining is impossible if the glasses have very different coefficients of expansion. The difficulty is usually overcome by interposing a glass oi' glasses of intermediate character. It has been

possible thus to join two glasses of widely differing character—pyrex

and soft glass—by means of a series of eight glass mixtures consisting of various proportions of pyrex and soft glass. Such joints

have proven to be satisfactory in service, but unfortunately attempts

to make the intermediate glasses on a somewhat larger scale proved

abortive because of the high temperature necessary to obtain uniform

mixtures.

Tubing of Good Quality for Glass-Blowing Purposes.

On account of the poor quality of soft glass tubing suitable for

glass-blowing use that is available on the American market, an

attempt was made to improve the situation. A sample batch of glass

made by the glass section at the Bureau was tested in that laboratory

and also sent for test to over 20 different authorities throughout

the country. So favorable were the comments received that an

effort is being made to interest certain manufacturers of glass in its production or in some modification that shall be equal to the best

German product of prewar days. • Minor Problems.

During the year many minor problems were presented to the

section, among them the following

:

(1) Preparation of universal wax for the use of the Bureau.

(2) Testing of explosibility of ammonia-air mixtures.

(3) Testing of ozonator for the production of ozone. ELECTROCHEMISTRY.

Included in this work are studies of electrodeposition used in electrotyping and electroplating, the latter being made up of in- vestigations of zinc, lead, nickel, copper, silver plating, etc.
152 REPORT OF DIRECTOR OE BUREAU OF STANDARDS.

Electroplating Investigations.

During the first part of the fiscal year the work upon the effect of

pickling on the physical properties of steels was completed and the

results were published. It was impossible, however, to complete

the work which was planned upon the effect of plating operations on the physical properties of steel. As opportunity offers it is hoped to continue this investigation.

Some time was also devoted to the study of zinc-plating solutions,

but it was impossible to carry these experiments to completion.

There is a great need for study of this subject, and such work should

be carried on as soon as possible.

Most of the time of this section during the year has been devoted

to cooperation with the Bureau of Engraving and Printing in

connection with the installation of a new plant for the electrolytic

production of printing plates. The preliminary studies were car- ried out at the Bureau of Standards, and the plant was designed and

installed under its supervision. The Bureau has also cooperated in

working out the manufacturing details of the process. This plant

is now in operation and is producing plates which have yielded very

satisfactory service. It is hoped that by addtional research and control work further improvements may be made which will permit

greater production and service.

Since this work for the Bureau of Engraving and Printing re- quired practically all the services of the section, it was not possible

to carry on any extended or fundamental investigations of plating.

The knowledge and experience gained, however, in connection with

the operation of copper and nickel solutions will, it is believed, be

of value both to electrotypers and electroplaters. So far as possible,

the information gained in this connection will be made public for

the benefit of the above industries.

Illustrated lectures upon the structure of electrodeposited metals were given to branches of the American Electroplaters' Society

located in a number of the principal cities. Through such lectures

and through the resulting discussions and correspondence, it is believed that the work carried on in this field can be made immediately

useful to the electroplaters, chemists, and manufacturers, and the

value and possibilities of such research work can be emphasized.

The American Electroplaters' Society, which is an educational and

scientific organization, has been of great assistance in promoting an

interest in an application of the results of scientific work in the

field of electroplating.

As a result of increased interest on the part of both electroplaters

and manufacturers, the field and need for reliable information upon

electroplating is increasing. Since the electroplating industry is usually carried out incidentally to other manufacturing operations,

its importance and magnitude are frequently OA'erlooked. When it

is realized, however, that it finds application in the manufacture

of practically all articles made of metal and that it determines

largely the attractiveness and service of the finished articles, its importance to the public can be readily appreciated. In the silverware

industry alone the value added by electroplating is sufficient to justify the expenditure of considerable amounts for research work to improve the quality of the products. The electrotyping industry is
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 153

fundamental to the whole printing industry and presents a field in

which there is as much possibility of improvement through research

as in electroplating. Many problems, such as nickel deposition, can

be studied to advantage with a view toward their application to both electroplating and electrotyping.

METALLURGICAL CHEMISTRY.

The preparation of metals and alloys required in connection with

meallurgical investigations and special methods of analysis for such

products are handled by this section.

The work done by the chemist^ division in connection with

metallurgy, however, is reported under "Metallurgy" (p. 244).

GAS CHEMISTRY.

Methods of preparation, purification, analysis, and testing of

gases, including fuel and illuminating gas, and special gases, such as hydrogen, oxygen, nitrogen, and argon, form the work of this section.

The Thermal Conductivity Method for Gas Analysis.

Probably not far from half of the time and energy of the section

has been devoted to the development of recording gas analysis apparatus depending upon thermal conductivity, and to the construction

of such apparatus for i*se in various Government establishments.

Ihe features of this apparatus which give promise of the most ex- tended usefulness in industry were invented and have been developed

to the point of successful commercial use within this section. The

first plant installation was a single-point recorder placed, just a

little more than a year ago, in the experimental helium plant of the

Bureau of Mines, at Petrolia, Tex. This apparatus was an immediate success and led to the demand for, and the construction of, another single-point recorder, two 6-point recorders, and one 16-point

recorder for use in connection with the various helium projects, one

4-point recorder for use in analyzing water gas at Langley Field,

and one hydrogen purity recorder for use at the same field. All of

this apparatus has been constructed and all but the 16-point apparatus has been installed. The two 6-point recorders, which determine helium, methane, ethane, and nitrogen in various mixtures are

reported to be giving particularly good satisfaction. The Bureau

has been requested to construct a 4-point recorder for determiningsulphur dioxide in the naval powder factory at Indianhead, Md.,

and another 6-point recorder for the Bureau of mines. Apparatus

was also constructed for the Fixed Nitrogen Besearch Laboratory at American University for the determination of ammonia, and the

Bureau was recently informed that when the large nitrate plant at Mussel Shoals is reopened it will be asked to supply the recording

equipment for that plant. Apparatus of this character is under construction elsewhere for at least five manufacturing concerns ; and one

university laboratory is known to have employed the method in ex- perimental work. The time required in constructing and empirically

calibrating this apparatus has prevented the important study of

fundamentals upon which further progress in its development must

be based.
154 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Balloon Fabrics.

The testing of balloon fabrics has continued along the lines established in previous years. A total of 1,449 individual tests were made

upon 349 samples. Most of this work has been clone in connection

with the efforts of the Army and Navy to develop a much less per- meable fabric of light weight and continuous gas film. During

the year the Bureau has developed and used methods for testing the

:strength and slippage of balloon seams at elevated temperatures.

Some fundamental work has also been done upon the permeability

of rubber to nitrogen and to water vapor. An exhaustive paper

upon " The Permeability of Rubber to Gases " has been prepared'

for publication.

Study of Laboratory Gas Analysis Methods.

The section has recently been able to begin the extensive program

of investigation of gas analysis methods outlined several years ago. A considerable amount of work has been done upon the development

of improved apparatus, and a theoretical and experimental study

of the absorption of gases by liquid reagents has commenced. The

preliminary results obtained in this study are of great interest, but

nothing is yet ready for publication.

Hydrogen Alarm for Use in Submarines.

The section has developed several dilfei^nt instruments for the

purpose of detecting the presence of hydrogen in submarines, and

has tested 10 or 12 instruments devised by others for the same purpose. On account of the extremely severe conditions to be met in

submarine service, none of these has proven satisfactory. Last sum- mer a new instrument was devised for the definite purpose of trying

to meet all the conditions which were responsible for the failure of

the earlier instruments, although to do this it was necessary to

sacrifice many of their advantages. The new instrument has been

tried out at the M ew York IS1 avy Yard with favorable results and has

been tentatively adopted for use by the Navy Department.

Bibliography of Gas Literature.

An extensive bibliography of the scientific literature relating to the physical and chemical, properties of gases, and including many

related subjects, is being prepared. About 11,000 references are now

included, and all have been very carefully arranged and indexed.

This bibliography is already proving of the greatest value, although

probably less than half completed.

Water Indicator.

Some time has been devoted to an effort to develop a satisfactory

indicator and alarm for the presence of minute traces of water vapor

in a gas. Such a device was urgently needed for use in connection

with the synthetic ammonia process employing sodium amide as a

catalyst. The apparatus developed, which depended upon the elec- trical conductivity of a film of some very hygroscopic substance,

such as phosphorus pentoxicle, was only moderately successful, and

work upon it was abandoned when it became apparent that the Fixed

]\ ltrogen Research Laboratory was no longer interested in the matter

since it had found a superior catalyst unaffected by water.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 155

Consulting Work on the Properties and Production of Gases.

The section is constantly receiving inquiries from many sources, but particularly from other Government departments, for information of all sorts relating to the production, handling, properties, and

analysis of gases. Such inquiries require a great deal of time in the

aggregate, and frequently lead to rather extensive investigations.

One such investigation involving some weeks of laboratory work was made to determine the practicability of a proposed process of making

acetone from carbon dioxide and methane. Another was concerned

with the desirability of trying to reduce the danger of balloon fires and to save hydrogen by burning the oxygen out of the balloon by means of electrically heated wires. At the present time the section

is working upon the important problem of improving the " Messerschmidt " process used by the Air Service at Langley Field and by

the Nav}' at Pensacola and Hampton Roads for the generation of

hydrogen.

New Automatic Method for Gas Analysis.

Preliminary work has been done upon an automatic method of

gas analysis depending upon the velocity of sound in the gas. This

method is believed to offer exceptional opportunities for the development of a very cheap and quick-acting apparatus for plant-control

work, especially for boiler firing.

Work for Other Divisions of the Bureau.

This section is frequently called upon to assist other divisions and

sections, usually by making gas analyses in connection with their

problems. An unusually heavy demand of this kind has recently

been made in connection with the oxy- acetylene welding tests con- ducted by division 7. A rather elaborate interferometer set-up was made for this purpose, and nearly 550 samples of oxygen were

analyzed.

REAGENTS AND APPARATUS.

In this work may be mentioned the study of methods of testing

reagents and apparatus to be used in chemical analysis, including

study of chemical glassware, poreclain, platinum, and platinum substitutes. Chemical Reagents.

OAving to reductions in the staff and lack of funds the systematic

study of the so-called " analyzed reagents " has been held in abeyance.

A limited amount of work has been done on the testing of reagents

purchased for the use of the laboratories of this Bureau. The results obtained indicate that there is room for improvement in many of the

reagents on the market. As the study of chemical reagents involves

standards of quality and standardization of methods of test it is of

direct interest to all scientific and industrial laboratories and indirectly affects all users of the products of the industries. For this reason means should be provided for prosecuting this work in a systematic way.

This study will be undertaken in cooperation with the American

Chemical Society and with the manufacturers of reagents. One- of
156 REPORT OF DIRECTOR OF BUREAU OE STANDARDS.

the sectional staff is a member of the American Chemical Societycommittee on " Guaranteed Reagents and Standard Apparatus,"

and has attended several meetings of this committee. The report of

this committee for the past year is published in the Journal of Industrial and Engineering Chemistry, volume 12, page 439 (May, 1920).

Chemical Apparatus.

The second annual meeting of the Association of Scientific Apparatus Makers of the United States, held at Washington, D. C, on

April 22 and 23, 1920, was addressed by the Director of this Bureau,,

and on invitation of the Director the members inspected the various

departments of the Bureau. This association is working in conjunction with the National Research Council, American Chemical Society,

Bureau of Standards, and various other scientific bureaus of the

National Government with a view to standardizing and thus cheapening the commoner and most used forms of apparatus.

Platinum Research.

The research upon the chemical and physical properties of the

platinum metals has been continued. This has consisted mainly in

the refining and preparation of the pure metals from the various lots of the impure metals loaned to the Bureau by the United States Assay

Office, and by the Nitrate Division of the Ordnance Department,

United States Army. About 600 grams of pure platinum, 100 grams

of pure palladium, and 75 grams of pure iridium have been prepared.

In this work a comparative study was made of certain methods of

purification of platinum and iridium. The knowledge gained in the

purification of these preliminary quantities will greatly expedite the

work of purifying the material on hand. Some experimental work

was done on the analysis of gold-palladium and gold-platinum alloys.

A series of platinum-iridiiun alloys, ranging from 0.01 to 1 per cent

iridium, Avere prepared for the spectroscopic section. Owing to the

press of other work and the reduced personnel, practically no progress

has been made in the study of the physical properties of the pure

metals and their alloys. However, a program for this investigation

has been formulated in cooperation with other divisions of the Bureau.

A representative of the Bureau visited and conferred with the various

platinum refiners and the technical staff of the United States Assay

Office. Analyses were made of various samples of platinum and

platinum-iridium wire for the War and Navy Departments. Special

check or referee analyses of nine samples of platinum sludge, representing 9,000 pounds of this material from a contact sulphuric acid

plant, were made for the Bureau of Supplies and Accounts, Navy

Department. This work involved a study of analytical methods and

the results were of value to the Navy Department in fixing the selling

price of this material.

A special fund having been appropriated by Congress for "the

purchase of platinum and other rare metals," the following have been

purchased to be used in the platinum metals research

:

Five troy ounces of osmium, 90 per cent pure. About 16 troy ounces of rhodium, about 95 per cent pure. About 7 troy ounces of ruthenium,- about 95 per cent pure.

Thirty-five troy ounces of Colombian platinum ore. About 22.5 troy ounces of pure platinum.

Fifty troy ounces of pure gold.

About 20 troy ounces of silver.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 157

Platinum Theft.

Between 4.30 p. m., March 17 and 9 a. m., March 18, 1920, about

70 ounces of platinum laboratory ware (mainly crucibles, covers, and

dishes), valued at about $10,900, were stolen from the Chemistry

Building. This ware was stolen from locked drawers. No platinum

in use, or not locked up, was disturbed. No clue has been obtained

in this case, although the matter was reported on March 18 to the

police authorities. However, on April 2 two men were arrested in

New York City trying to sell about 284 ounces of platinum sponge.

This platinum was claimed by a New Jersey firm that had been

robbed late in December. 1919. As the platinum stolen from this

Bureau might have been in this lot, the Bureau of Investigation of

the Department of Justice, at the request of the Bureau of Standards

had their agents look into the matter. A member of the Bureau's

staff was sent to New York to assist in this investigation. The pris- oners claimed that the platinum was obtained by placer mining in

Ontario, but this statement was proven false. A sample of the material was brought to this Bureau and a careful analysis made, showing platinum of higher purity than the usual metal of commerce and

of totally different composition from that lost by the New Jersey

firm. The Bureau of Chemistry, U. S. Department of Agriculture,

assisted this Bureau by making a microscopic examination of the

physical structure of the sponge. The results of the analysis indicated that the sponge was probably obtained from platinum chloride

solution of a purity attained by the U. S. Assay Office in the refining

of platinum for use in war-time powder plants. TJie chloride solution is used to impregnate the " contact mass " used in the manufacture of sulphuric acid. Deductions drawn from certain apparently

irrelevant statements made by one of the prisoners, and suggestions

by a member of the staff of the U. S. Assay Office, led to the conclusion that the material was stolen from a Government munitions

plant, either at Nitro, W. Va., or at Jacksonville, Tenn. Although

the officials of the Ordnance Department reported that their platinum stocks had been checked up and found intact, the investigation was continued. A visit was made to Wilmington, Del., to inspect

certain photographs of former employees, and then to Nitro, W. Va.,

without any results. Finally, the Old Hickory Powder Plant, near

Nashville. Tenn., was visited, and an inspection of the employment

records of former employees led to the identification of one of the

men under arrest in New York. Further inspection at this plant

showed that at least 2,250 ounces of platinum sponge, prepared from

platinum chloride solution by their chief chemist, were missing. As

the result of these disclosures, the man in custody in New York confessed to complicity in the theft of the platinum from the Old

Hickory plant, involving the chief chemist as the principal in the

matter. The latter was placed under arrest and at present writing

the two men are awaiting trial. Miscellaneous Tests. Comparative tests of laboratory glassware were, made for the

Medical and Hospital Supplies Division of the War Department.

Tests of ampules were also made and assistance rendered in the

preparation of specifications for ampules, medicine bottles, test tubes,

and various chemicals. In cooperation with the manufacturers, tests
158 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

were made of American-made filter paper. The results indicated

that this paper is superior to most of the papers on the market and

practically equal to the best foreign-made paper.

ANALYTICAL METHODS AND STANDARD SAMPLES.

These investigations cover 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 samples called for during the fiscal year 1919-20 was 5,676, as against 4,944 in the year 1918-19, a gain of 732. The

distribution was as follows: Irons and steels, 3,9 73; brass, 104; ores, 346; sodium oxalate, 409; naphthalene, 163; benzoic acid, 298;

sucrose, 138 ; dextrose, 33 ; metals for melting points, 135 ; cement for

testing sieves, 77. The popularity of the samples is again attested by the largely in- creased demand and is the strongest possible argument for a restora- tion of the special fund which was stricken out of the appropriation

bill for the year 1920-21. In order that the needs of the industries

and of educational establishments may be adequately met, the special

fund formerly provided for this purpose should be restored, and

increased to $15,000. With this amount annually assured it would

be possible to place the whole Avork upon a self-supporting basis. Certainly only a lack of understanding of the situation could have

led Congress to fail to provide this appropriation of $5,000 for work

which brought to the Federal Treasury more money in fees than the

sum appropriated. The fee value of the samples issued in the past

fiscal year was over $11,000.

Two new samples were added to the list during the year—No. 49,

melting-point lead, and No. 50, chrome-tungsten-vanadium steel, and

two others (No. 51, a high-carbon steel, and No. 52, a cast bronze)

will soon be added. Seven samples were renewed and six other re- newals are in various stages of mechanical treatment. Analytical Methods.

Apart from the preparation and distribution of standard samples,

the work of the section has consisted in research on analytical

methods and in analytical work on materials which did not properly

fall to any of the routine laboratories.

LUBRICATING OILS, RUBBER, PAPER, TEXTILES, INK, AND GLUE.

This section is concerned with chemical analysis and investigations

of oils, rubber, paper, textiles, ink, glue, airplane dopes, etc., with

special reference to meeting particular requirements.

Airplane Dopes.

Before the end of the preceding fiscal year there was a marked

falling off in the work on these materials. At present only an oc- casional sample is received for test. The subject has been so well

worked out and dopes of such excellent quality are now being made
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 159

that it is necessary only to test delivery samples. Unless some new

basic material supplants cellulose acetate, it is not likely that there

will be any great improvement over what is now used.

Rubber.

Full details of the Bureau's work on rubber, including that of the

chemistry division, are given in the report on rubber (p. 210)

.

Textiles.

Various dyed fabrics were tested for fastness of color. Samples

of woolen and silk goods were analyzed to determine their composition. A considerable part of the work was the determination of the oil content of numerous samples of rope and the examination of flax packings.

At the request of the National Safety Council, tests were made of

ropes which had been specially treated to make them resistant to the

action of acids. Various bituminous and other mixtures were pre- pared and used. A more complete account of this work will be

found under division 7, page 180. In cooperation with the War Department the bleaching and dyeing

of stained cotton was studied. This cotton became discolored while

still in the boll, and varied from yellow to bluish. It was found that

it could be bleached without serious difficulty and eoidd then be dyed

any desired color. The bleaching was not neeessarjr when the cotton, was to be dyed in shades of brown or olive drab.

Pearl Buttons.

A great deal of time was spent in attempts to bleach bixttons made

from the shells of the fresh-water clams of the Mississippi and its tributaries. The white buttons are the most valuable, but they can be

made from only a small percentage of the shells. Most of the shells are colored pink, yellow, broAvn, or gray shades that may be almost

black. Some of these colors are due to organic compounds produced

by the clam, while others are the result of the deposition of fine silt upon the shell when the water is muddy. The iron compounds in the silt can not be removed without dissolving also the calcium car- bonate of the shell. The organic colors can be bleached by treatment

with hydrogen peroxide, at least to some extent. Ultraviolet light

also removes these colors, but this process is slow and expensive.

Fireproofing Fabrics.

The aerial mail service of the Post Office Department was very

anxious to have the mail bags fireproofed so that in the event of an

accident the mail would be in a measure protected. Tests were made

of a number of samples submitted, and fabrics were treated by dif- ferent processes before the problem was solved to the satisfaction of

the service.

Filter Paper.

Because of the fact that it is desired to produce filter paper in this

country which will prove as satisfactory as that formerly made

abroad numerous samples of paper pulp and paper were investigated.
160 REPORT OF DIEECTOR OE BUREAU OE STANDARDS.

in cooperation with the paper section. These samples were treated

with acid in order to learn how much ox the mineral matter could be

removed in the manufacture of ; ' ashless " filter paper. Various

papers were tested for speed of filtration and for retention of fine precipitates.

Clay for Paper Filler. A considerable number of clays, mostly from American sources, were analyzed for the paper section to determine their suitability for

paper making.

Printing Inks.

There was practically no routine testing and analysis of these materials, but considerable time was spent in developing a method for

the quantitative measurement of certain of their physical properties

upon which their behavior in the press depend. The method can be

applied as well to other materials of the same nature, as paint pigments in oil, tars, etc. Writing and Copying Inks.

A great many writing and copying inks were tested to assist the

General Supply Committee and the Post Office Department in awarding contracts, and also to check deliveries made on purchases.

The use of ink powders and tablets and of concentrated ink seems

to be on the increase. As stated in last year's report, these can not

be recommended for use in connection with permanent records if only dyes are employed in their manufacture. However, several

brands of powders and tablets now on the market contain the in- gredients of iron gallotannate ink of good quality. Properly made

concentrated ink should also be entirely satisfactory if it is not too strongly diluted. These remarks apply only to' black inks. Red

and other colored inks are always made from dyes, and there can

be no objection to their being put on the market in dry form.

Stamping, Marking, and Related Inks.

Among the other kinds of ink tested were stamping, duplicating,

stenciling, and similar inks. These were given tests designed to show whether or not they were suitable for the purposes for which

they were intended.

Typewriter Ribbons.

Many ribbons for use on typewriters, adding machines, etc.. were

tested. The quality of the fabric, the amount of ink, and the per- manence of the writing were all given consideration.

Carbon Papers.

The nature and amount of the coating were determined. The

number of copies obtainable and their freedom from smudging are important considerations.

Glue, Mucilage, Paste. Xumerous samples were tested during the year for different

"branches of the Government.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 161

An interesting piece of work was the preparation of glue from

salted fur-seal flippers, at the request of the Bureau of Fisheries.

The dried and salted nippers were first cut up and soaked, after

which they were boiled to obtain the glue. A comparatively large

yield of good glue was obtained. It had the disadvantage of a

rather strong fishy odor.

Miscellaneous Materials.

Among the miscellaneous materials tested or analyzed were the

following: Chestnut bark extract for making black writing ink,

leather softeners, vulcanized fiber, celluloid, laboratory porcelain

and grinding waste from the manufacture of saws.

METALS, CEMENT, BITUMINOUS MATERIALS, ETC.

The field covered by this section includes the chemical analysis of

metals, among which may be mentioned 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,

and bituminous materials, including tars, asphalt roofing papers,

roofing felt, etc. Chemical Work on Metals and Alloys.

Because of depleted personnel very little except routine testingcould be done in connection with metals and alloys. Mention is made

in the following paragraphs of a few of the special problems pre- sented for investigation.

Analyses were made of a number of German motor parts of vari- ous makes, which showed that chrome and chrome-nickel steels were

used to a considerable extent. In the absence of these alloying ele- ments high carbon and high manganese steels were used.

A sample of nichrome wire was received for examination from the

Inventions Section, General Staff, United States Army, which had

been in constant use at red heat for four years. The iron content was very low, and the general composition was similar to the alloy

chromel. Such wire may prove to be suitable for a variety of uses. An interesting alloy, " aterite," haA'ing a very high coefficient of

expansion, resistant to corrosion, and not softening below 1,000° C. was found to have the following composition : Copper, 52.4 per cent

;

zinc, 9 per cent; nickel, 30.7 per cent; lead, 1.9 per cent; tin, 0.8 per

cent ; iron, 4.5 per cent ; manganese, 0.3 per cent ; carbon, 0.14 per

cent. At the request of the Navy Department, the effect was studied of

approximate marine conditions upon " stainless, " steel for use in

periscope tubing. The cooperative study included preparation, heat

treatment, microscopic examination and salt spray tests of 14 samples of steel. The results indicate that this type of steel is of advantage for the use proposed.

Tests to determine the effect of water saturated atmosphere upon

electrical contact springs having various depths of gold plating over

steel finish, electroplated zinc, and sherardized zinc, were made. The

tests indicated that the gold-plated sherardized coatings were mark10613—20 11
162 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

edly superior in their resistance to corrosion by the moisture-laden

atmosphere.

In preparation for tests to be made in cooperation Avith the American Society for Testing Materials to determine the effect of immersion in running water upon sheet metal, 882 samples of 16 and 22

gauge metal were prepared, of which 294 will be tested at the Bureau.

Antifreezing Solutions.

During the year numerous requests have been received for copies

of our preliminary report on antifreezing solutions for automobile

radiators. Press of other work has prevented extension of the work

to a degree that would justify a subsequent report. Of the materials

submitted for use as antifreezing agents there is none which warrants

the recommendation of solutions other than of alcohol and water. Boiler Waters.

Numerous inquiries for information concerning the problems in- volved in handling steam boilers indicate widespread interest and

the need for more investigational avoi'K. Bituminous Materials.

* Prepared Roofing.—The war-time specification for prepared roofing has been revised. The statement that the roofing obtained under

that specification was inferior was investigated by inspection of many

buildings in several of the Atlantic States and analysis of the material used. Failure was, in most cases, due to improper or careless

methods of laying or because the samples were originally not truly

representative. Also, as the specification was prepared under wartime conditions, concessions had to made of which some are not now

necessary, so the revised specification has been designed to insure a product of higher grade. Only a very limited amount of prepared

roofing is now used by the Army, but the specification is used by the

Panama Canal and is available for general use. An investigation was also undertaken to determine if tensile or bursting strength of the roofing as received and after exposure was

a measure of quality. The results were negative, for Avhile the

strengtn was increased by exposure because of hardening of the

felt, as was to be expected, no relation was observed that could be in- terpreted as a measure of quality.

Built-up Roofing—Few specifications other tnan those of manufacturers have been available for built-up roofing, in spite of its importance in the more permanent class of construction, where it is being used to an increasing extent by the Office of the Supervising

Architect of the Treasury and by the Navy Department. These offices have asked the Bureau for assistance in formulating more definite

specifications.

Coatings for Concrete Ships.—The original specification for a bituminous coating for concrete ships called for a fairly hard coat- ing, so as to prevent flow from water pressure. The importance of

this point was apparently overestimated, and it is now felt that a

softer coating to bridge cracks is desired. The specification has been

modified accordingly. The information is applicable to other needs

than concrete ships and is being so utilized.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 163

Chemical Analysis of Cement and Lime.

The routine and chemical testing of cement declined markedly

during the year. Full details of the Bureau's work on cement are given in the report on cement, page 188. In cooperation with the interdepartmental lime committee and at the request of the lime section of the Bureau an investigation was made of the various methods for " available lime " in such materials

as quicklime and hydrated lime with variable magnesia content. Of the seven short-cut methods tried only the Scaife method seemed

to have any apparent value. Further work is now being carried out

to see if this method can be modified to give better results. Miscellaneous Tests. About 90 samples of alkali soils and waters were analyzed to obtain

data for various investigations of the cement section, which is con- ducting a study of the effect of alkali waters on cement drain tile. In response to many inquiries for a method of rendering concrete

resistant to acids a bituminous coating has been tentatively recom- mended for the purpose.

In analyzing asphalt varnishes a method was needed for determining the fatty oils. Such a method has been developed which

depends on solubility of the fatty acids in ether and later ethyl

alcohol, in which the bitumens are insoluble.

PAINT, VARNISH, AND SOAP.

This section is concerned with the chemical analysis, testing, and

exposure tests of paint and varnish, as well as the chemical analysis

of and specifications for soap. Cooperation with Paint Manufacturers' Association.

Arrangements have been made with the educational bureau, Paint

Manufacturers' Association of the United States, and National Varnish Manufacturers' Association for cooperative work on problems

of interest to the paint and varnish industries. This association was

given the use of the Bureau's facilities from November 18, 1919, jto May 15, 1920, during which time the specific gravities and "bulking

figures" of most of the pigments on the American market at this

time Avere determined. The results, which will be published by the

Paint Manufacturers' Association with proper credit to the Bureau,

should prove of considerable value to the paint industry, since the

data are necessary for accurate calculations of yield and hence cost per gallon of manufactured paints.

Interdepartmental Committee on Paint Specification Standardization.

This committee has been very active and has made good progress. While the greater part of the labor and responsibility of preparing

the specifications issued has been borne by this Bureau, the other

members of the committee have rendered invaluable service. The

specifications so far issued will probably cover more than half the

materials necessary for general protective painting; and while the

work of the committee will never end, it is believed that the most

difficult of the really important phases of its work have been covered.
164 REPORT OF DIRECTOR OE BUREAU OF STANDARDS.

CHEMICAL TESTING AND PUBLICATIONS.

Chemical Testing.

The number of chemical tests made in the chemical laboratories

during the fiscal year was 9,317. This number is hardly more than

half that of the preceding year, but the decrease is natural, being a direct result of the lessened activities of the military branches of

the Government since the close of the Avar. Distributed by types of

materials, the tests were as follows : Ferrous metals (irons and steels)

,

757 ; nonferrous metals, alloys and coated metals, 867 ; cement and

cement materials, 1,746; bituminous products (including creosotes,

etc.), 47CK; varnish materials (including shellacs), 651; paint materials, 1,258; lubricants, 1,025; soaps, nondrying oils and metal polishes, 643 ; inks and related office supplies, 442 ; balloon fabrics, 391

;

rubber, 498 ; leather, 25 ; textiles, 242 ; miscellaneous, 302. The tests were made for very many Government bureaus and establishments and for States, municipalities, and private parties among

which may be mentioned the following: Agriculture, 24; Commerce,

4,170 (this includes samples received from other divisions of the Bureau for chemical tests) : Interior, 14; Labor, 2; Navy, 444; Post

Office, 609 ; Treasury, 848 ; War, 1,510 ; Panama Canal, 932 ; General

Supply Committee of the District of Columbia, 436; United States

Shipping Board, 160 ; other Federal institutions, commissions, and

committees, 54; State, municipal, and other institutions, 40; private

parties, 29 ; foreign and allied commissions, 1. Publications in Chemistry.

The following papers emanating wholly or in part from the

chemistiy division were published during the year

:

Scientific Paper No. 369, The Vapor Pressure of Ammonia. Published also in Journal American Chemical Society, volume 42, page 206, 1920. Glass to Metal Joints, published in Journal American Chemical Society,

volume 42, page 1364, 1920. Factors Governing the Structure of Electrodeposited Metals, published in Transactions American Electrochemical Society, volume 36, page 57, 1919. Lead Plating from Fluoborate Solutions, published in Transactions American

Electrochemical Society, volume 36, page 101, 1919. Notes on Black Nickel Plating Solutions, published in Monthly Review Ameri- can Electroplaters' Society, volume 6, page 14, 1919. Operation of Fluoborate Lead-Plating Baths, published in Monthly Review

American Electropftxters' Society, volume 6, September, 1919. Embrittling Effects of Cleaning and Pickling upon Carbon Steels, published

iu Transactions American Electrochemical Society, volume 37, page 305, 1919. Technologic Paper No. 158, A Peculiar Type of Intercrystalline Brittleness of Copper.

Determining Gases in Steel, and the Deoxidation of Steel, published in Bulletin No. 152, American Institute of Mining and Metallurgical Engineers, August,

1919. Technologic Paper Xo. 141, Electrolytic Resistance Method for Determining

-Carbon in Steel. Automatic Methods of Gas Analysis Depending upon Thermal Conductivity,

published in Journal Industrial and Engineering Chemistry, volume 12, page

359. 1920. New Forms of Combustion Apparatus for Use in Gas Analysis, published in Journal Industrial and Engineering Chemistry, volume 12, page 368, 1920. A Weight Burette for Gas Analysis, published in Journal American Chemical

Society, volume 42, page 1177, 1920. The Testing of Balloon Fabrics, published in Report No. 39 in Fourth Annual

Report, National Advisory Committee for Aeronautics.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 165

The Ferrosilicon Process for the Generation of Hydrogen, published in Report

No. 40 in Fourth Annual Report, National Advisory Committee for Aeronautics. Testing of Balloon Gas. published in Report No. 41 in Fourth Annual Report,

National Advisory Committee for Aeronautics.

Scientific Paper No. 387, The Permeability of Rubber to Gases, appeared in Chemical and Metallurgical Engineering, volume 23, 1920.

Scientific Paper No. 359, Efflux of Gases Through Small Orifices. Preparation and Testing of Hydrogen of High Purity, published in Journal

Industrial and Engineering Chemistry, volume 11, page 961, 1919. A Method of Determining the Permeability of Balloon Fabrics, published in Journal Industrial and Engineering Chemistry, volume 11, page 966, 1919. Generation of Hydrogen by the Reaction Between Ferrosilicon and Sodium

Hvdroxide. published in Journal Industrial and Engineering Chemistry, volume

12, page 232, 1920. Determination of Zirconium by the Phosphate Method, published in Journal

American Chemical Society, volume 41. page 801, 1919. Determination of Zirconium in Steel, published in Journal Industrial and

Engineering Chemistry, volume 12, page 562, 1920. Determination of Zirconium and Titanium in Zirconium Ores, published in Journal American Chemical Society, volume 42. page 1439, 1920.. The Use of Cupferron in Quantitative Analysis, published in Journal Industrial and Engineering Chemistry, volume 12. page 344, 1920. The Detection and Determination of Glue in Rubber Goods, published in The

Rubber Age, volume 0, page 109, 1920; India Rubber World, volume 6, page

216, 1920. A New Method for the Determination of Sulphur in Oils, published in Journal Industrial and Engineering Chemistry, volume 12, page 482, 1920. Circular No. 95. Composition. Manufacture, and Methods of Testing Inks. Technologic Paper No. 354, The Determination of Cellulose in Rubber Goods.

Also appeared in Rubber Age, volume 6, page 299, 1920. Technologic Paper No. 162, The Extraction of Rubber Goods. Also appeared

in Rubber Age. volume 6, page 445, 1920. A New Hexabromide Test for Linseed Oil, published in Journal Industrial and Engineering Chemistry, volume 12, page 52, 1920. Circular No. 84. Recommended Specification for Basic Carbonate White Lead,

Dry and Paste. Circular No. 85, Reeohimended Specification for Basic Sulphate White Lead,

Dry and Paste. Circular No. 86. Recommended Specification for Turpentine:

Circular No. 87, Recommended Specification for Zinc Oxide, Dry and Paste. Circular No. 88, Recommended Specifications for Leaded Zinc Oxide, Dry/

and Paste. Circular No. 89, Recommended Specifications for White Paint and Tinted

Paints Made on a White Base, Semipaste and Ready Mixed.

Circular No. 90. Recommended Specifications for Red Lead. Dry and Paste. Circular No. 91, Recommended Specification for Ocher, Dry and Paste. Circular No. 93, Recommended Specification for Iron Oxide and Iron Hydroxide Paints. Circular No. 94, Recommended Specifications for Black Paint. Semipaste and

Ready Mixed.

The following are in preparation or in press

:

Notes on the Use of Hydrofluoric Acid in Nickle-plating Solutions.

Specific 'Volume of Saturated Ammonia Vapor.

Preparation of Pure Ammonia.

Vapor Pressure of Carbon Dioxide. Density and Expansivity of Sodium Chloride Solutions. Formation and Prevention of Noncondensable Gases in Ammonia-absorption:

Refrigeration Machines.

Equilibria in the System Carbon Disulphide—Methyl Alcohol and Carbon; Disulphide—Ethyl Alcohol. Investigation of New Deoxidizers for Steel. The Application of the Thermal Conductivity Method to the Automatic Analysis of Complex Mixtures of Gases. A Thermal Conductivity Method for Gas Analysis. Thesis. University of Southern California.
166 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Recording Gas-Analysis Apparatus in the Helium Plant at Petrolia, Tex. The Inflammability of Jets of Hydrogen and Inert Gas. The Determination of Aluminum as Aluminum Phosphate.

The Quantitative Precipitation by Ammonia of Phosphorus Pentoxide in Company with Alumina.

The Determination of Molybdenum in Steel. The Volatilization Losses of Phosphorus Pentoxide During Operations Involv- ing Fuming with Sulphuric Acid or Fusion with Pyrosulphate.

Sulphur in Petroleum Oils. Comparative Tests of Porcelain Laboratory Ware. The Carbonization of Oils. Circular Xo. 3S (Revised Edition), Rubber Goods. Slushing Oils. Recommended Specification for Green Paint. Semipaste and Ready Mixed.

6. ENGINEERING PHYSICS.

Investigations relating to mechanics, sound, and properties of matter; testing and develop- ment of engineering instruments; performance standards of mechanical appliances; sound

ranging: investigation of soundproofing properties of building materials; analysis and correc- tion of acoustical defects of assembly rooms; elastic properties of diaphragms and springs;

investigation, testing, and experimental development of aircraft instruments; aerodynamical

testing and research. ENGINEERING INSTRUMENTS AND MECHANICAL APPLIANCES.

Water-Current Meter Rating Station.

An important engineering service rendered by the Bureau is the

furnishing of accurate calibrations of water-current meters. These

instruments are used for the measurement of the velocity of the water

in rivers, irrigation canals, and other open channels to determine the

quantity of water discharged. Such data are essential in waterpower development, irrigation, flood prevention and similar

projects, but involve the use of a large body of still water, means for

moving the instruments through the water at. uniform speeds, and

apparatus for recording the observations; an installation too extensive and costly to be undertaken by private enterprise. The Bureau

rating station furnishes exceptional facilities for the study and cali- bration of instruments of this class. The station flume is entirely

housed in and is operated throughout the year. During the past

fiscal year 251 current meter ratings were made for different engineering branches of the Government, private engineers and water

companies and for instrument manufacturers.

Calibration of Instruments.

During the past fiscal year a total of 175 instruments, in addition to current meters referred to above, were calibrated, including

pressure gauges of various descriptions, anemometers, water meters,

odometers, engine indicators and the like. Hub Odometers.

At the request of the War Department, work is in progress to secure data on which to base standard performance specifications for

odometers for Army motor trucks.

Tests of Thermostatic Heating Valves.

An investigation, previously undertaken at the request of the

Supervising Architect of the Treasury Department to establish per- formance standards for thermostatic valves used on radiator outlets
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 167

in vacuum-heating systems, was continued to include tests of devices

recently developed. Twelve valves of a new type or design were

tested under working conditions during the past year. Investigation and Tests of Fire Extinguishers,

At the request of the Steamboat-Inspection Service the investigation and testing of hand chemical fire extinguishers and similar ap- paratus submitted to that Bureau for its approval for use on vessels under its jurisdiction was continued. Sixteen devices of this character were tested for compliance with standards previously determined as a result of this work, or independently investigated

when new types or principles of operation were involved.

Miscellaneous Tests and Examination of Appliances.

A variety of miscellaneous tests of mechanical appliances were made, among which may be mentioned physical tests of 16 samples

of air-tight caskets under consideration by the War Department for overseas use; performance tests of acetylene-regulating valves; tests of air pumps, pressure-relief valves, automatic gas shut-off valves,

gauge glasses, and similar appliances.

On several occasions inventions were studied and an opinion of

their feasibility and value rendered at the request of the Inventions

Section of the Army General Staff. AERONAUTIC INSTRUMENTS.

The work of the aeronautic instruments section includes the in- vestigation, testing, and experimental development of all types of

aircraft instruments, such as altitude-measuring instruments, rate-of- climb indicators, engine speed and air speed indicators, navigating

instruments and accessories, airplane and balloon pressure gauges,

gasoline-supply gauges, inclinometers, banking indicators, turn in- dicators, bomb sights, and oxygen-control apparatus; also mercurial

barometers, weather and surveying aneroids, and sphygmomanometers. There are also included the development of methods of

testing, improvement in design, fundamental researches on the physical principles of such instruments, the study of their operation in

actual service, and the determination of the corrections required for

aircraft-performance tests. Clearing House for Instrument Information.

During the past year there has been an increasing demand for

scientific information relating to every aspect of instrument work.

The aeronautic instruments section has served as a central agency

for the coordination of such information which has been applied

for by manufacturers and by representatives of the military, naval,

and post-office aviation services, and not infrequently by delegations

from foreign countries.

Study of Foreign Instruments.

A member of the section has been detailed to represent the Bureau

abroad during the past year. He has established additional official contacts and pleasant cooperative relations with the aviation and

scientific authorities in England, France, Italy, Belgium, and Hoi-
168 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

land, and has collected, for official use by the Bureau, the latest European instruments and technical information. In return he has

been able to place at the immediate disposal of the proper authorities

abroad the current results of the Bureau's investigations. This ex- change of technical data has been very much facilitated through the

courtesy of the commercial attache service of the Department of

Commerce. The results of this work have been of considerable value

and interest in this country in view of the relatively greater activity

of aeronautic research and development in Europe.

Additions to the Instrument Collection.

Extensive additions have been made during the year to the Government collection of aeronautic instruments which is maintained

by the Bureau of Standards. Among these may be mentioned a variety of German instruments for both airplane and balloon navigation and some of the latest instruments of British manufacture,

including a gasoline-flow meter of novel design, a turn indicator,

and a density meter for correcting air-speed readings.

Technical Publications.

A group of manuscripts with very full illustrative material has

been nearly completed for publication through the National Advisory Committee for Aeronautics under the title " General Beport on Aeronautic Instruments." In the preparation of this report the

entire staff of the aeronautic instruments section and several experts

from other divisions of the Bureau have cooperated. This report

will form a fundamental contribution to the literature on aero- nautic instruments and show quite completely the state of the art

at the end of the war. A paper which will serve as a preliminaiy

introduction to the foregoing material has been presented before the

American Society of Mechanical Engineers and will be published

in the transactions of the society for 1920. This paper deals with

the general principles of construction, testing, and use of aeronautic

instruments. The various types of instruments are systematically

classified and briefly described. The principles involved in the different methods of testing are discussed and suggestions are given

for securing the best results from instruments in. practical use. The following additions have also been made during the year to the

series of Aeronautic Instruments Circulars which are distributed

in mimeographed form, with blue prints and photographs, for

temporary use by the Government and authorized investigators : Pressure-Altitude Tables (fourth edition, revised and extended) ; Airplane Compasses; Investigation of Master Tachometers; Description and Theory of Rate-of-Climb Indicators; Average Besults

of Performance Tests on Airplane Tachometers ; Design for Dummy

Observer; Bureau of Standards Rate-of-Climb Indicator, Model No.

3. A -French translation of the Descriptive List of Aeronautic In- struments Circulars was prepared and found useful by the Bureau's

representative in his conferences abroad.

Material for Instruction Courses.

Photographic and descriptive material for use in courses of instruction on the subject of aeronautic instruments have been supplied at
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 169

the request of the Massachusetts Institute of Technology, the United

States Army Air Service, and. the Bureau of Navigation of the Navy

Department.

Salvage of Aeronautic Instruments.

A statistical study is being made of the actual causes of failure in

aeronautic instruments. Such facts are really the foundation for

intelligent improvement of design in the future as regards the ordinary standardized service instruments with which all planes are equipped. During the past year the aeronautic instruments section

of the Bureau has salvaged for the air mail service a collection of

tachometers, magnetic compasses, radiator thermometers, air-speed

indicators, and airplane pressure gauges. A quantity of barographs

were submitted for salvaging by the air service of the Army, and a number of these instruments have been reconstructed so as to function over a higher range of altitude. The salvage problem consists

of dismantling a certain number of damaged or defective instruments and putting them together, so as to form a smaller number of

good instruments accurately readjusted and compensated for temperature. Routine Testing.

The amount of testing done by the aeronautic instruments section

during the past 12 months,for outside agencies may be classified as follows

:

5 mercurial barometers.

13 ordinary aneroid barometers.

38 altimeters. 57 barographs and altigraphs. 16 air-speed indicators. 20 tachometers or speedometers.

18 miscellaneous instruments, including airplane pressure gauges, ther- mometers, sensitive manometers, inclinometers, rate-of-climb indi- cators, and aii ship computing devices. The testing done in connection with the Bureau either on developmental projects or the instrument collection has not been included in

the foregoing summarj'.

Flight Tests on Aircraft Instruments.

In cooperation with the Army and Navy, the section has continued

to make occasional flight tests on aeronautic instruments. Information often comes from the comparison of flight test results with laboratory results on the same instrument, which would not be readily apparent from either type of test taken b}^ itself. Among the most in- teresting flights made by the members of the section during the 12

months just closed, may be cited a trip in the French dirigible at Langley field, the Zodiac, in which observations were made on the

performance of a new type of air damped compass; a series of air- plane observations, flying level at different altitudes and speeds, for

the purpose of securing a practical check on the results of the laboratory experiments on air-speed indicators at reduced pressure ; a series of flights for the intercomparison of different types of rate-of-climb

indicators; and a flight for the practical demonstration of the

" dummy observer," which was recently developed by the Bureau.
170 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Conferences with Manufacturers.

Since it is the function of the Bureau of Standards to assist in building- up American industries, including the instrument in- dustry, the section has continued to confer with manufacturers from

time to time during the ye&v, although there has been no demand at

this time for large-scale production. Some of the more important

subjects which have been taken up during the j

T ear with the respective manufacturers are

:

Diaphragm construction. Improvement of thermographs.

Oxygen apparatus.

Special inks to withstand low temperatures.

Sphygmomanometers.

Aneroid barometers. In this way the Bureau has cooperated with the manufacturers

in regard to keeping up the quality of their product and has had

available for the use of the aviation branches of the Government at

all times an up-to-date survey of manufacturing resources in the in- strument field. Altitude Computation.

The past year has witnessed great popular interest in world's

record altitude competition. The Bureau has cooperated with the

Air Service of the Army and the Aero Club of America and all persons interested in formulating as definitely as possible the best

procedure for determining the most probable altitude reached. The

Bureau has also assisted in the selection and testing of the in

struments themselves,, which have to be of exceptional quality to afford reliable results in high-altitude flying on account of th

mechanical strain and low temperature experienced.

L- (

Diaphragm Investigation.

This problem of research was mentioned in last year's report and

has been continued. It was undertaken at the request of the National Advisory Committee for Aeronautics and is evidently one

of the most important lines of investigation in progress in the sec- tion, because of the variety of different instruments for which thin,

flexible diaphragms are necessary. Results have already been

secured along five principal lines, namely

:

1. The mathematical theory of irreversible effects which cause

the lag in diaphragm instruments has been systematically formu

lated.

'

2. Charts have been prepared showing the relation between force

and deflection for diaphragms of different sizes, thicknesses, and

materials, and these results have been generalized by the method

of dimensions so as to throw them into a useful form for practical

design.

3. Further experience has been gained and information compiled

regarding practical methods for spinning or forming diaphragms

and building up diaphragm boxes.

4. Preliminary conclusions have been reached regarding the pos

sibilities of mechanical seasoning by repeated stress.
REPORT OF DIRECTOR OE BUREAU OF STANDARDS. 171

5. A series of experiments has been completed in cooperation

with the Geological Survey, using delicate optical methods for determining the experimental laws governing the departure from perfect elasticity of specimens of very thin sheet metal used for

diaphragms. Five different alloys have been investigated, and these

experiments should be continued.

Sphygmomanometers.

At the request of the medical department of the Army and of

several manufacturers a s}T stematic comparative investigation has

been made of commercial sphygmomanometers, which are used in

blood pressure cleterminattion in examining the physical fitness of

a visitors and for general physical examinations by the medical profession. The results of this work will provide a reasonable basis

for specifications and have revealed the principal defects which ought

to be improved in future development. Both diaphragm and mercurial types have been examined, and to facilitate the tests a precision mercurial standard has been constructed, which was designed

with special reference to the needs of this class of work.

Direction Indicators.

A study has been made of the characteristic sources of jerror in

the different types of instruments which are used for determining

the direction of an aircraft, including gyroscopic and liquid incli- nometers and banking indicators, gyroscopic and magnetic compasses,

and turn indicators.

Navigating Instruments.

At the request of the National Advisory Committee for Aeronautics

and also of the Air Mail Service of the Post Office Department, the

Aeronautic instruments section has been compiling information re- garding instruments available for aerial navigation in cloudy

weather or at night, and over long distances. At the request of and

in cooperation with the navigation branch of the Army Air Service

this work will be actively continued and the development of new

instruments taken up. Altitude Effect on Air-Speed Indicators.

Experiments have been completed which will shortly be prepared

for publication, through the National Advisory Committee for

Aeronautics, on the change in the performance of Venturi tube air- speed indicators due to change in atmospheric conditions. The re- sults show that certain instruments in common use are subject to a correction for the viscosity of the air which has not hitherto been

taken into account. This result is of interest especially where the

air speeds are comparatively low, as in dirigible work, or where ex- ceptional precision is called for, as in performance testing of air- craft. A miniature wind tunnel has been used for this work which was so arranged that reduced pressures could be maintained cor- responding to conditions at high altitudes. It is planned to continue the investigation next year so as to include the examination

of additional types of instruments. The construction of new equipment for this purpose has begun.
172 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

German Aeronautic Instruments.

A report is in preparation summarizing the results of an investigation of the various types of German instruments which have been

collected by the section, including the combination gyroscopic turn

indicator and banking indicator, electric-resistance thermometer for

dirigible balloons, and a remote indicating compass.

Dummy Observer.

The application of the moving-picture film for recording instrument readings during the flight of an airplane, referred to in the

previous report, has been completed during the year and turned over

to the Air Service. It consists of a group of especially selected performance test instruments suitably illuminated and arranged in a box

with automatic timing control for the camera. It takes the place of an additional human observer on the airplane and affords records

which are more accurate than those which could be obtained by the

ordinary recording instruments.

Rate-of-Climb Indicator.

The Bureau of Standards rate-of-climb indicator, model No. 3, has

been completed and successfully tested. This instrument reads

directly the rate of climb in hundreds of feet per minute ; its operation depends upon a capillary tube and an exceptionally sensitive

diaphragm, dispensing entirely with the use of liquid. Specifications were prepared for the Balloon and Airship Division of the Army, on

the basis of which a contract was placed for manufacturing a number

of the instruments.

Precision Altimeter.

The large precision altimeter developed by the Bureau has passed

its tests successfully, showing almost complete freedom from elastic

lag. This design was based on the principle of making the diaphragm so very flexible in comparison with the spring that the

quality of the diaphragm metal could not appreciably influence the

result. A steel spring superior to the commercial grade was then

prepared by the metallurgical division of the Bureau. A second

model has recently been designed in which additional improvements

are introduced. Such an instrument has been very much needed for

performance testing of aircraft.

Turn Indicator for Airplanes.

A new type of turn indicator for aircraft has been developed by

the gas-measurement section of the division of weights and measures. Turn indicators are extremely useful to aircraft flying in fogs, in

clouds, and at night to enable the pilot to fly his craft in so nearly

a straight line that his compass will function properly and to pre- vent him from unknowingly flying in a circle of such small radius

that his machine will get out of his control. The particular type of

turn indicator which has been developed depends upon the principle

that, due to inertia, a jet of air issuing from a short tube fastened

to the airplane frame will not change its direction relative to the

earth at the. same instant that the airplane does. Hence, by placing

a suitable indicator in the path of the jet it should be possible to
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 173

detect instantly any deviation of the aircraft from a straight line. While this principle has not been made use of before in such instruments, trial tests have indicated that it is practical. It is very simple

mechanically and will probably be quite inexpensive to manufacture.

It is planned to publish a detailed description of this instrument in the near future.

Contrast Between War and Peace Activities.

The work of the aeronautic-instruments section during the war

was directed mainly toward problems of quantity production and

testing. The total volume of work called for is to-day fully as great

as it Avas in the summer of 1918, but the character of the work has

changed. The main activities now are along the three following

lines : First, systematic investigations which will form the basis for

scientific construction and performance specification in the future;

second, gradual development of improvements in the standard service

instruments by the scientific solution of fundamental difficulties,

notably in the case of centrifugal tachometers; third, design and

development of special instruments for aerial navigation and per- formance testing of aircraft. In all of this recent work, also, there

has been a relatively greater emphasis placed upon instrument problems relating to dirigible balloons than was the case during the war. AERODYNAMICAL PHYSICS.

Resistance of Projectiles at High Air Speeds.

Kesistance measurements of projectiles have in the past been made

through actual firing tests, in which the deceleration of the projectile was determined hj measuring the successive time-intervals

involved in the passage of the projectile through a series of screens. This method necessitates the measurement of short time intervals

with great accuracy since the rate of change of the Velocity is re- quired in order to determine the deceleration. During the past year

a series of direet measurements of the resistance of projectiles of

various types has been carried out in cooperation with the Ordnance

Department of the Army. The investigation has been conducted at the works of the General Electric Co. at Lynn, Mass., with the aid

of powerful centrifugal air compressors manufactured by that company. The compressor delivered air under pressure to a large

vertical standpipe 3 feet in diameter, fitted at its upper end with

a suitably designed orifice 12 inches in diameter, through which the

air expanded adiabatically. The resistance measurements were made

in the air stream as it issued from the orifice. The projectile to be measured was rigidly attached by its base to the lower end of a vertical spindle, which in turn was supported

from a vertical piston in an accurately ground cylinder. The whole

apparatus was supported on a horizontal stream-lined arm, so ar- ranged that the projectile and its mounting could be swung into the

air stream Avith the projectile pointing directly at the issuing jet.

By varying the pressure in the cylinder the projectile could be made

to float in the air stream. The observed differential pressure at this

moment and the constants of the apparatus provided the necessary

data for determining the resistance. A similar measurement with
174 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

the projectile in position below the spindle but supported, from an

independent mounting gave the correction for the resistance of the

spindle.

With the equipment as described it has been possible to obtain

resistance measurements at any desired air speed up to or slightly

exceeding the speed of sound in air. Shadow graphs have also been

obtained showing stationary sound waves in front and at the rear of

projectiles held in the air stream, when the latter was moving past

the projectile at a speed of 1,250 feet per second. The measurements

made so far give promise of being of great value in the study of

external ballistics and the work will be continued.

Wind Tunnel Measurements on Projectiles.

Supplementing the work described above, a series of measure- ments on the resistance of projectiles has also been conducted in the

high-speed Avind tunnel at the Bureau, in Avhich a maximum wind

speed of 250 feet per second can be attained. This work has included

the direct measurement of the head resistance of the projectile both

by direct and indirect methods. In the direct measurements, the

projectile was suspended from wires and its deflection downstream

at various wind speeds was determined. Suitable correction for the

supporting wires was, of course, applied. In the indirect measurements, the pressure was determined at various points over the sur- face of the projectile, and especially across its base, and the resist- ance calculated by integrating the axial component of pressure over

the entire surface of the projectile.

Head Resistance and Stability of Aircraft Bombs.

In cooperation with the Ordnance Department of the Army the

aerodynamical characteristics of a series of wooden models of bombs,

geometrically similar to, or modifications of the Mark II highcapacity drop-bomb, have been determined in the 54-inch wind tunnel during the past year. A few of these determinations were checked

in the 36-inch wind tunnel of the Bureau, and in the 8-foot tunnel

at the Washington Navy Yard. While the relative magnitudes of

the air forces and moments on different bombs as determined in the

wind tunnel are of value in ballistic problems, it is not justifiable to extrapolate the head resistance to high speeds in order to obtain

the terminal velocity of a bomb which approaches the velocity of

sound. The terminal velocity computed from the head resistance as determined in the wind tunnel has been found to be about 30 per

cent greater than that measured in the vertical fall of a bomb from

a balloon. The oscillations of the bomb, starting with an initial amplitude of 10°, lead to a sufficient increase of the average head re- sistance to account for a large part of this difference.

A stream-line bomb model often has a knver head resistance than

the mounting supporting it. Even when all corrections are made

for the effect of mounting, the head resistance as determined by the

bifilar suspension method is at least 10 per cent greater than that de- termined by balance measurements.. The measurement of the head

resistance of the Mark III model on the Bureau's aerodynamical

balance checked within 4 per cent with balance measurements in the

navy-yard 8-foot tunnel, notwithstanding the fact that the Mark
REPORT OF DIRECTOR OF BUREAU OF STAXDAEDS. 175

111 model is the largest model that is permissible in the 51-inch

tunnel.

The Mark II model was cut in two at its maximum cross-section

and cylinders varying in length from one to four times the diameter

of the bomb were inserted. The bomb with an insert two diameters

long has a smaller head resistance than the same bomb with an insert one diameter long. Check runs in the 36-inch wind tunnel with

bifilar suspension yielded the same relative results. Logarithmic decrements of the oscillations of the Mark II model

were determined in the 51-inch tunnel for several wind speeds. For

drops from elevations up to 2.000 feet, for which data on oscillations

in free fall were available, this linear damping effect is small. The

greater part of the damping is due to the increased restoring torque

of the fins with increase of speed. The calculation of the period of

oscillation, even from incomplete equations of motion, check the

results obtained from dropping tests to about 30 per cent. Aerofoil and Airplane Model Tests. The aerodynamical characteristics of a series of biplanes of varying

stagger and decalage have been determined in the 51-inch tunnel.

One wing of the combination was B. A. F. 15, and the other the sjmmetrical form of H. F. Parker's variable camber wing. These biplane

combinations, in general, show less biplane interference than where

both wings are of the ordinary type. The report on these tests has

been submitted to the Xational Advisory Committee for Aeronautics,

with whom the Bureau cooperated in the work, for publication.

Longitudinal stability tests were carried out on two models of

the Johns multiplane (seven wings) of the American Multiplane Co.

The determination of the tail plane characteristics gave significant

results and showed the' great desirability of further model experimentation on this type of design.

Longitudinal stability tests were made on the biplane model submitted by Ensign G. B. Linderman, both with ground landing gear

and seaplane floats. The forces on the stabilizer-elevator group were

determined, and an estimation of the performance of the full scale machine made, using the land-type landing gear. In a later series of tests a complete longitudinal and lateral static stability determination was made.

Complete static stability tests were carried out on a model of the

internally-braced monoplane of the American Aircraft Co. Deter- minations were made of the force and moment components referred

to three axes fixed in the model at four angles of pitch and at varying

angles of yaw up to 20°. Air Resistance of Spheres.-

The sphere is a difficult body to investigate aerodynamically on

account of the turbulence it produces, but its geometrical form is such as to make the determination of its resistance by several different

methods possible. The investigation has included a measurement of

the resistance (1) by a balance method, in which the sphere was supported on a spindle: (2) by a deflection method, in which the sphere was suspended from wires; (3) by a dropping method, in which the

deflection of the sphere when falling freely across a wind stream was
176 REPORT OF DIRECTOR OE BUREAU OF STANDARDS.

determined. This last method involves no correction for supports,

while in the other two methods the resistance of the spindle and supporting Avires must be determined.

The influence of wind-tunnel conditions on air-resistance measure- ments has also been investigated by the application of the principle

of dynamical similarity to observations on spheres of different di- ameters.

Interesting results have been obtained relative to the effect of the

roughness of the surface of a sphere on its resistance. It has been

found that roughening the surface lowers the so-called critical speed,

at which point a marked change occurs in the character of the flow

about the- sphere, accompanied by a large reduction in the resist- ance coefficient. The result is that at certain wind speeds a sphere

with a smooth and highly polished surface offers a greater resist- ance to the wind than a sphere of the same diameter with its sur- face roughened or "brambled" like a golf ball. Roof Ventilators.

At the request of the War Department and the industry a test was made in 1918 to determine the relative efficiency of various types

of roof ventilators, which are supposed to produce a suction in the

pipe to which the ventilator is attached when the Avind blows across the ventilator head. At the suggestion of representatives of the

American Society of Heating and Ventilating Engineers, these tests are now being extended to include the efficiency of ventilators at lower air speeds than were used in the earlier tests. A study has

also been made of the character of the flow around ventilators of

various types, with a view to improving their efficiency. The resist- ance offered by different tvpes of ventilating heads when the flue is functioning simply a? a chimney has also been determined. A re- port on the subject is in preparation.

Measurement of Low Air Speeds.

The work described above necessitated the measurement of air

speeds below 5 feet per second in a pipe 16 inches in diameter. A

simple device was developed in the laboratoiy which met this re- quirement satisfactorily. It consisted of a very small, straight wire

12 inches long, hanging freely in a horizontal pipe and fastened at

its upper end to a small horizontal staff supported on jeweled bearings. The bearing block was supported from the top of the horizontal pipe, the staff being normal to the wind direction. The deflection of the wire by the wind stream was observed through a window in the side of the pipe. The apparatus was calibrated

directly by means of an orifice 2 inches in diameter temporarily in- troduced into the pipe, the wind speed being determined by the drop

in pressure through the orifice. The equipment has proven very

useful for measuring low air speeds in horizontal pipes.

SOUND.

During the year the sound laboratory has made very satisfactory

progress in developing equipment for its peculiar kind of work.

This type of equipment is in general not commerciaDy available, and

must be designated and constructed in the laboratory in which it is to be used.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 177

Acoustic Properties of Building Materials.

In response to an increasingly insistent demand for information

on the sound transmission and absorption properties of building

materials, an investigation having for' its object the collection of

data covering the most common materials was begun. In connection

with the construction of hospitals and hotels the Bureau has been

asked to state what materials would permit the use of Avails of

minimum thickness consistent with adequate acoustical insulation.

Questions of this kind are confronting the architect almost daily,

and it is the aim of the Bureau to continue the investigation so that

reliable information regarding the acoustical properties of presentday building materials may be available.

Acoustic Properties of Assembly Rooms.

Considerable difficulty has been experienced in various Federal

court rooms and other assembly rooms of the Government departments, owing to inability of auditors to hear comfortably. This dif- ficulty is largely due to reverberation ; that is, the continuation of

the sound after the source has ceased to emit. In some cases it was

found that the sound heard at any instant included from 10 to 20

preceding syllables, leading to annoying confusion. The Bureau has

cooperated with the Supervising Architect of the Treasury Department in correcting the difficulties in existing structures and in pre- venting them in other instances through suitable design in advance

of construction. Four cases of the former kind and two of the latter were handled in the course of the year for the Treasury Department

alone.

The Triode Drive of Tuning Fork.

The electrically driven tuning fork has, in recent years, come into more frequent use as a small-scale time standard. The contact method of drive has been a frequent source of trouble, particularly

when the frequency of the fork is 500 cycles or higher. A vacuum

tube method of drive has been developed at the Bureau, which insures

the continuous operation of the fork with a relatively large amplitude and with a remarkable uniformity of period.

Precise Measurement of Small Time Intervals.

The success attained in driving a tuning fork continuously at a very constant rate opened the way for making measurements of time

intervals with a high degree of accuracy. Using a 500 cycle fork,

timing indices one-thousandth of a second apart were obtained on a moving film, successive indices being spaced several centimeters

apart. This combination constitutes a chronograph which permits

measurements to at least hundred-thousandths seconds for approximately lj seconds, or to ten-thousandths seconds for 25 to 30 seconds.

This chronograph has been used to make the following measurements, which illustrate its range of availability : (1) Measurement of

projectile speeds up to 2,800 feet per second over distances of 10 to 20 feet; (2) determination of the acceleration characteristic of a

linall turbine attaining a speed of 6,700 r. p. m. in 3 seconds from

rest; (3) measurement of the time-lag between a control clock and

the controlled radio time signal, the lag being of the order of seven- 10613—20 12
178 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

hundredths of a second: (I) measurement of the operation time of

photographic shutter.

Cooperation with the War Department.

Technical data on the parabolic sound reflector used for locating

aircraft were obtained for the Engineer Corps of the United States Army. The aim of this work, which is still in progress, is to obtain

fundamental data upon whicb efficient design of such an instrument can be based.

Substantial assistance was given the Technical Staff of the Ordnance Department in a program of work on air resistance of projectiles.

SPECIAL INVESTIGATIONS.

An investigation of the possible fuel economy of jet propulsion for

aircraft was undertaken for the Army Air Service and gave un- expectedly interesting results. At flying speeds corresponding to those obtainable at the present time, jet propulsion would require a much greater fuel expenditure than a motor-driven air screw. On

the other hand, the relative efficiency of jet propulsion increases with

the flying speed and this novel method of propelling an airplane

may have important military applications in short flights where fuel

economy is of secondary importance.

A study was made of the conditions that must be fulfilled in

order that model experiments on the resistance of ships to submarine

explosions may give reliable results for designing purposes. This was undertaken in consequence of a communication on the same subject from the Italian Government. A paper on the subject will soon be ready for publication.

A paper dealing with some of the obscure points in the theory of

dimensions has been completed and a book on this subject is in course of preparation. The theory of dimensions provides an effec- tive means of attacking many physical problems and is indispensable

in experiments involving models. Xo general treatise on the subject

is at present available.

7. STRUCTURAL. ENGINEERING, AND MISCELLANEOUS

MATERIALS.

Nearly all the materials ordinarily used in industrial work are investigated and tested by

this division. These include metals of all kinds, when made up into structures or parts of structures, wood, cement, concrete, stone and sand, leather, rubber and composition materials used in place of these, textiles, paper, lubricating- oils, lime, gypsum and sand-lime

brick. The work of this division is of such a nature that very often the investigation of a

structural material requires the study of the manufacturing process by which it is pro- duced, and for this reason the equipment includes, besides a complete assortment of test- ing machines, an experimental rubber mill, textile plant, paper machine, cement plant, etc. METALS.

In these laboratories measurements are made of the resistance of

engineering materials, particularly of metals and wood, under tensile,

compressive, and torsional stresses. The fatigue and impact re- sistance of materials, as well as their hardness are subjects of

careful study. Especially is attention given to the design of test- ing apparatus and to testing methods in general in order that these
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 179

may be improved. The properties of new materials are determined

so that they may be used successfully by the other Government

departments, the industries, and the public. Attention is given to the alloys of aluminum having low weight, because of their importance in the construction of aircraft. Engineering structures

are designed and tested to determine the construction most suitable

for a given purpose. Many of these are tested under load to observe the behavior of their parts. Among these tests may be in- cluded ones upon machine and airplane parts, buildings, and cranes.

Strain Gauge PAeasurements of 350-Ton Crane.

The Navy Department has recently built at Philadelphia a. 350-

ton fitting out crane for placing heavy objects, such as turrets, in

position on board ships. This crane, one of the largest in the

world, attracted a great deal of attention from engineers and the

general public during the latter part of 1919. This structure is statically indeterminate, and therefore stresses in the members can

not be calculated. At the request of the Bureau of Yards and Docks

of the Navy Department, a study was made of several compression

members of this crane, using a strain gauge to measure the change

in length of these members under load. From these readings the

change in stress was calculated. The work was carried out during a very severe winter. It was necessary to erect platforms near the

top of the structure, exposed to high winds, rain, and sleet. In spite

of these difficulties the results were satisfactorily consistent.

Efficiency Tests of Oxyacetylene Torches for Welding and Cutting.

During the recent war the War Department found that it was unable to prepare specifications for the purchase of oxyacetylene torches,

due to the lack of sufficient data concerning apparatus of this kind.

On account of the need for securing the best kind of cutting and

welding equipment, this Bureau was requested to make efficiency

tests of the commercial torches, about fifteen in number. The tests were made to determine the amount of gas used in welding one-half

and three-fourths inch steel plate and in cutting one-half inch, 2

inch, 6 inch, and 10 inch steel. Data were secured upon the ratio of

the gases used, the conditions under which flash-back occured, and

the general suitability of the apparatus as to safety, strength, etc. It was necessary to spend several months in preparing the apparatus

as the amount of gas was determined by weight and also by a care- fully calibrated orifice flow meter. Manometers were used to measure the pressures. Recording pressure gauges were also used to se- cure a continuous record. The report upon the results is now in

preparation and will be furnished to the Army for their use with

suggestions on purchase specifications of these torches.

Fireproof Airplane Wings.

The fact that airplane wings and fuselage constructed of wood

and covered with doped fabric are highly inflammable has been the cause of many deaths when accidents occurred in flight. The possibility of death from this cause is believed to greatly lower the

morale of the Air Service. Metal has now been proven suitable as
180 REPORT OF DIRECTOR OP BUREAU OP STANDARDS.

a substitute for wood in an airplane structure. In order to produce a completely fire-proof airplane, it will be necessary to secure a fire- proof covering for the wings in place of the fabric at present in use. A study of the materials which can be used sIioavs that corrugated

metal such as used in the Junker airplane is satisfactory. Its weight, however, is several times that of the present fabric.

Thin sheet metal stretched over the structure like a fabric appears

to be unsuitable due to its low tear resistance. If used, it might

readily rip sufficiently to cause disaster if injured by a bullet. If

this material is reinforced by wire mesh its tear resistance would be

satisfactory. Metal wire mesh or screen could be used if provided

with, a satisfactory covering so that it would present a smooth surface. Experiments have shown that a paint film may be applied to a wire mesh having openings of one-tenth inch if thin paper is applied to one side. A paint film of this kind is sufficiently fire resistant to allow gasoline to be burned from the surface without propagating

the flame.

The position of the pilot in most planes is such that his vision is greatly restricted by the wings and other portions of the structure. A transparent covering for the wings would prove valuable if used

for several feet near the cockpit. Sheet celluloid is higldy inflammable but cellulose acetate, such as used for fireproof moving-picture

film, if supported by a wire mesh, would probably prove satisfactor}T

. The weight, however, would be much greater than the present fabric

wing covering. Tests have been made to determine the tensile and bursting strength as well as the tongue and tear resistance of many types of wing covering. The results are given in a preliminary report, Letter Circular

VII—1-12, giving the mathematical theory and a survey of the possible materials.

Effect of Acid on Rope.

Muriatic acid is often used to clean the stonework of buildings and

monuments. If the acid comes in contact Avith the rope supports of

the SAAT inging staging required by the workmen, the strength of the

rope is greatly impaired. Many accidents resulting in loss of life have occurred from this cause. It was suggested that a protectiAr e compound which has been found

successful in protecting metal work from the deteriorating influence

of acid be used on rope. Tests were made by exposing the specimens

of rope to fumes of muriatic acid and also by dipping them in acid

solutions. The tensile strength was then measured. It was found

that in many cases rope of three-fourths inch in diameter could be

broken in the hands. Apparently the compound offered no protection. Metallic BelloAvs. The Army wish to use metallic bellows in connection with the con- struction of ordnance, but at the present time are unable to obtain

them. One of the officers engaged on this work devised a method of

forming the belloAvs and at the request of the Army this method was

tried at the Bureau of Standards. The results together with a number of suggestions for improvements were embodied in a report.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 181

Specimens of the bellows obtained were also supplied to assist in perfecting the apparatus which was demonstrated to representatives of

the Army interested in this problem.

Cause of Failure of a Railroad Bridge.

At the request of Iowa* State authorities, the failure of a railroad

bridge which had been in service for 30 years was studied. Consideration of all the information which could be obtained, supplemented by tests of portions of the material, led to the conclusion that

the design of the bridge was unsuitable for the heavy loads which it had been carrying in recent years. The spacing of the rivets was

less than that allowed by good practice at the present time, a feature

which emphasizes the necessity of including the rivet spacing in

structural specifications. The material near the failure showed that

it had been repeatedly overstressed, and this was probably the immediate cause of failure of the bridge.

Mexican Woods.

The United States consul at Mazatlan, Sinaloa, Mexico, submitted

32 specimens of wood for determination of their phj^sical properties.

They were chiefly the heavy hard woods which Avould receive a high

polish. The local names for many of them were used, as it was

impossible to find their botanical descriptions.

The tests included the moisture content, and the strength in compression and cross bending. The results showed that many of them

had considerable commercial value if they could be obtained in sufficient size at reasonable cost. Strength of Struts for Flying Boats. In preparing designs for large flying boats similar to those which

recently crossed the Atlantic, several types of struts were under consideration. About 15 specimens, prepared by the Navy Department

and by manufacturers of wood veneer, were submitted for compressive tests to check the accuracy of their computed strength. The

inconsistency of the results led to over 100 tests of the wood of which

they were made. These showed a wide variation in the strength of

the material but a direct relation between the strength of the wood

and that of the strut made from it, as the struts having the highest

strength were constructed from exceptional material and the weak

struts from material having a low strength. 4 When the modulus of

elasticity of the wood was used in Euler's column formula, values were obtained which agreed closely Avith experimental results on

the struts. It was found also that some of the struts were made from basswood.

The strength of these would have been much greater if spruce had

been used.

Experimental Data for Design of Autofrettage Guns.

The usual method of constructing large guns by shrinking of one

tube or hoop upon another is difficult and expensive. Eecently a method, successfully used in France and known as " autofrettage,"

has been developed, by which the desired initial stresses in the gun

are produced by overstressing it by internal hydraulic pressure. In
182 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

this process much of the material is stressed beyond its elastic limit. As this is unusual in engineering practice, few experimental data are

available for design work of this kind.

Experiments were therefore made for the Ordnance Department of

the Army to determine the relation of the lateral deformation to the

longitudinal deformation upon steel specimens of varying cross sec- tions subjected to both tensile and compressive stress which con- siderably exceeded the elastic limit of the material.

Several different methods were tried before one was found which

gave results of sufficient accuracy. A large number of observations were made and the results indicate that much information of value

to engineers and others would be obtained by a more extensive investigation along this line. Bearing Pressure on Ball and Roller Bearings.

Bearings for the trunnions of large guns should have little fric- tion, but must withstand heavy loads when the gun is fired. The

use of ball and roller bearings is desirable, but little information is available regarding the maximum loads for bearings such as these,

which move slowly and infrequently. Tests were made at the request of the Navy Department upon commercial steel balls and rolls to measure the area of contact between

the ball or roll and the loading surfaces, the amount of compression

and the resistance to motion for both flat and cylindrical bearings.

It was found necessary to design and construct special apparatus, and

the tests are still in progress. Strength of Metal Fence Posts. At the request of the Indian Service, seAreral commercial types of

steel fence posts suitable for use on Indian reservations were tested

for strength and resistance to impact.

The selection of a post suitable for the soil, climate, and service

conditions, which vary widely, is a matter of importance, due to the

large number of posts purchased each year. The report included, in

addition to strength tests, recommendations upon the location of the

" spade " and other details. Fatigue Resistance of Copper and of Iron Tube.

Many forced landings of mail planes in the Postal Air Service are caused by fracture of the copper tube connecting the feed tank with

the engine. The suggestion that wrought iron would probably have

a greater fatigue resistance and that tubes made of this material

would therefore be more durable than copper led to comparative

tests in the rotating beam-testing machines in the materials laboratories. The results were not conclusive, as the testing machines were unsuited to specimens of such small diameters. The average of the

values obtained for each showed a somewhat greater fatigue resist- ance for the iron tubes, even though they had very rough surfaces.

Several failures occurred where the tube was stamped with the trade name. If iron tubes could be obtained having the smooth surfaces

and uniformly thin walls of the copjDer tubes, it is probable that they

would proA'e much more serviceable than those now in use.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 183

Joint Committee on the Investigation of Sulphur and Phosphorus in Steel of the American Society for Testing Materials.

The staff of this section is represented on the subcommittee on

statistics of this committee. This subcommittee has spent much

time in seeking material which has failed in service and which either

shows normal or high sulphur and phosphorus content. For this

purpose personal visits have been made to the Army and Navy representatives in a position to supply this material or any information

regarding it. The representatives of some of the leading railroads

and automobile manufacturers have also been consulted.

A number of specimens have been obtained from the railroads, but none from the other organizations. This material will be submitted

to chemical and physical tests. A bibliography upon this subject

has been prepared and distributed.

Committee on Heat Treatment of Carbon Steels of the National

Research Council.

This committee is preparing and testing carbon steel specimens to determine the physical properties which can be obtained by heat

treatment. Cooperating with the other members of the committee, physical

tests have been made in these laboratories upon about 50 specimens

and the results reported to the chairman of the committee.

Safety Code for Elevators.

The staff of this section has, during the year, spent considerable

time in cooperation Avith the electrical division and a committee

of the American Society of Mechanical Engineers in the preparation

of a safety code for elevators.

Numerous valuable suggestions have been submitted for the consideration of the committee, many of which have been adopted. A

large amount of time was also devoted to editorial revision of the

manuscript before publication in order to secure the best possible

form of presentation.

Methods of Testing Hardness of Metals.

This section through representation on the committee on hardnesstesting machines of the National Research Council has devoted considerable time to the problems before this committee. Several meetings have been held and plans perfected for carrying on research

work by individual members of the committee in their laboratories.

The section has designed and made drawings of apparatus for

calibrating the loading of the Brinell hardness-testing machines.

These are now being considered by the committee.

Materials for Aircraft.

A member of this section, as secretary of the committee, has prepared

programs for the meetings of the committee on materials for aircraft

of the National Advisory Committee for Aeronautics. The use of

duralumin in airplane construction has been considered, particularly

with reference to the well-known Junker all-metal plane, constructed

in Germany. Several meetings have been held for the preparation

of specifications of stream-line wire for airplanes. This subject has

received careful consideration by the committee and much experi-
184 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

mental and other work done in preparing a specification which would

insure reliable material.

Development of Remote Reading and Recording Electrical Strain

Gauges.

During the Avar the activities of the section on electrolysis pre- vention of the electrical division were largely diverted to various

military problems, especially those arising in connection with the

location of hostile batteries by sound ranging. An important ele- ment in this problem was the development of suitable electrical devices for recording the arrival of the sound waves at different points.

The recording devices considered and developed for this purpose

appeared to have so many possible uses that further work on them

seemed advisable, and considerable time has been given particularly

to the development of recording strain gauges or extensometers. Instruments have long been available for application to structural

elements to indicate the steady stress caused by dead loads on the

structure, but until recently no progress has been made toward making these instruments recording. Quite recently two recording strain

gauges have been developed elsewhere, but both of these are subject

to the disadvantage that the whole of the apparatus must be mounted

directly on the element under test, thus making it practically impossible to use them on any members not readily accessible. So far as the Bureau is aware, no progress whatever has previously been made

in securing a remote recording strain gauge, and the work of the

Bureau in this field has been strictly of a pioneer character.

The objective in this work has been to develop extensometers which

shall be remote reading and remote recording so that relatively small

parts may be placed on the structural members under observation,

the bulk of the equipment being placed at some more convenient and

accessible location, and also to make an instrument capable of recording transient stresses due to live loads. An incidental object has

been the measurement of initial stresses clue to the weight of the

structure itself. A number of different physical principles have been studied with

a view to their use in the construction of gauges. The instruments on which more or less experimental work has been done include contact resistance devices, split core transformers, capillary tube instruments, vibration type of instrument, and bismuth wire instrument.

Very promising results have been obtained and some instruments

are now being given a practical trial, although much development

work remains to be done.

The field of usefulness for apparatus of this type, not only on

airplanes, but on bridge members and structures of many kinds, is very great, and it is highly desirable that these investigations be

carried on until the apparatus can be made available for the wide

variety of uses to which it is adapted.

Special Tests. The protection of wood members of an airplane structure from

moisture is important, as the strength may be reduced to one-half that

of dry wood and the weight is also greatly increased. To find the

actual condition which existed in seaplanes in service the Navy Department submitted specimens of wood cut from planes that had been

in service at Chatham, Mass. ; Key West, Fla, ; Great Lakes Training
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 185

Station, 111.; and Pensacola, Fla., for determination of the moisture

content and specific gravity.

An artillery wheel formed from sheet steel was tested for the

artillery division of the Ordnance Department of the Army. The

results showed low strength clue to the few welds which secured the

rim to the wheel.

Summary of Tests. The following statements show various materials tested by this

section during the fiscal year ended June 30, 1920, together with the

number of specimens of each type

:

Metals. Iron and steel

:

Cast iron 15

Steel 1,115

Total 1,130

Ahuniuuni and aluminum alloys

:

Aluminum alloy 25 Aluminum alloy, duralumin 35 Aluminum alloy, lynite 36

Total r 96

Copper, brass, and bronze : Bronze 245

Miscellaneous metals and alloys:

Bearing metal, " copded " 9 Dental amalgam 6

Electrolytic nickel and copper 40

Total 55

IVood. Airplane 110 Columns 6. Auto loading blocks 5 Paper roll cores 2

Field desk interiors 2

Total 125

Fiber rope and wire rope. Rope, manila 73

Aircraft cord 4 Duraeord L 1 Parachute cord 1

Cordage- 6 Cotton twine 1 Tarred lanyard 2 Tarred marline 2 Wire and wire rope 118 Wire cable 4

Total 212

Other material. Bakelite insulating material 16

Electrosote insulating material 18

Total 34
186 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Calibration of testing machines.

Riehle torsion testing machine . 1

Riehle universal testing machine, 50,000 pounds 1 Riehle testing machine, 100,000 pounds 1

Scott horizontal testing machine 1 Schopper tensile testing machine, 1,000 kilograms 1 Olsen chain testing machine, 2,000,000 pounds 1

Total.

Miscellaneous. Bayonets 4

Belt, leather 1

Bolts and nuts 38 Bomb lugs 12 Chain link 6 Clamp 3

Drills , 3

Fiber, hard horn 8

Firing pin, 240-millimeter howitzer 8

Glass, panes 44

Glass, bottles 354 Hacksaw blades 29 Hand grenade bodies 24 Hard rubber storage battery cases 6 Hinges, strap _, 2 Hook, metal , 2 Jacks 2

Knives, butcher 2 Lenses 82

Light structural material 5 Locomotive packing ring 10 Machetes 8 Meat cleaver 1 Motor truck valve 1 Nut locks 27 Paper clips, brass 20 Paper scales 16

Picture film 1

Piston rings 1 Pneumatic tire 1 Redmanol 4 Red fiber 1

Rivets 10 Screws 39

Seals, Acme 6

Seals, Asbo 1

Seals, baling 23

Seals, Brooks 4

Seals, Signode 20

Shell rotating band 3

Shells 2

Spectacles 16 Spring 1

Strapping, bos 2 Storage battery cases, vulcanized rubber 48

Tire base bands 1 Torpedo propellers 4 Turnbuckle 1 Welded specimens 500

Total 1, 407 Grand total 3,310
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 187

Material Tested for Other Divisions of the Bureau of Standards.

Division I : Lenses. White hard horn liber. Yulcanized-rubber storage-battery

cases. Steel spring.

Telegraph wire.

Electrosote. Magnet wire. Bakelite. Hard-rubber storage-battery cases. Bronze wire rope. Division II : Screws.

Division V

:

Hard horn fiber. Electrolytic nickel and copper. Aluminun» alloy rivets.

Division VII

:

Redinanol.

Picture film. Calibration of testing machines.

Rope.

Calibration of apparatus.

Division VIII: Welded specimens. Bronze. Locomotive packing rings.

Bearing metals. Cast iron. Firing pins. Steel (nickel, gun barrel, rifle barrel, carbon and chrome va- nadium).

Storeroom : Paper scales. Materials Tested for the War Department.

Air Service

:

Light structural material. Balloon cable. Box strapping and seals. Turnbuckle and strap. Metal hooks. Engineer's Office : Skein bolts. Field Medical Supply Depot:

Signode strapping and seals. Acme seals. Inventions and Experimental Section

:

Aeroplane guy wire. Aluminum alloy-lynite.

German rifle-barrel steel. Bayonets. Motor Transport Corps

:

Steel. Motor-truck valve. Piston ring.

Nut locks. Materials Tested for the Navy Department.

Ordnance

:

Shell-rotating band. Hand-grenade bodies. Steel bars. Steel bolt. Shells. Bomb-suspension lugs. Hard-drawn brass wire. Purchase, Storage, and Traffic

:

Rope.

Clamps.

Butcher knives. Meat cleavers. Field-desk interiors. Baling seals. Quartermaster Corps : Steel-tire base

bands.

Bureau of Construction and Repair

:

Moisture content and specific gravity of airplane wood.

Aluminum and aluminum alloys. Duralumin, acerial, Huron metal,

lynite. Steel forgings.

Nickel steel tube. Aluminum-alloy rivets. Parachute suspension cord.

Bureau of Ordnance

:

Aircraft cord.

Steel test bars. 5 and 6 inch steel diaphragms.

Naval Gun Factory, Washington

:

Calibration of testing machines.

Torpedo propellers.

Alloy-steel springs.

Navy Yard, Boston : Calibration of 2,000,000-pound chain machine.

Materials Tested for Other Branches of the Government.

Department of Agriculture: Forest Service—Telephone wire. Bureau of Public Roads—Steel re- inforcing rod. Department of Commerce

:

Bureau of Lighthouses—Glass. Department of Interior: Bureau of Mines—Steel test bars. Geological Survey—Duracord.

Government Printing Office: Paperroll cores.

Panama Canal Commission

:

Drills. Structural steel. Paper clips. Wire.

Trolley wire. Hacksaw blades. Chain links. Manila rope. Bolts and nuts. Machetes.
188 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Panama Canal Commission—Contel. Tarred lanyard and marline. Bronze-wire cable. Steel cable. Cotton and torpedo twine. Superintendent State, War, and Navy

Building'

:

Cast iron. Wood columns. Materials Tested for Commercial

Ultra glass. Plain glass. Bottles, glass. Jacks.

Steel. Bronze.

Spectacles.

United States Railroad Administration : Welding wire. Nut locks. Riehle torsion machine.

Steel. United States Shipping Board, Emergency Fleet Corporation : Steel cast- ings and steel bars. Organizations.

Auto loading blocks. Wedge bolt. Strap hinges. Calibration bars. Rope.

Leather body belt. Turbine studs. •

Publications.

The following is an enumeration of the publications which were

prepared by this section : Technologic paper No. 150, Physical Tests of Motor-Truck Wheels, by Charles

P. Hoffmann.

Technologic paper No. 151, Load Strain-Gauge Test of 150-Ton Floating.Crane

for the Bureau of Yards and Docks, by Louis J. Larson and Richard L. Templin.

Technologic paper No. 152, Investigation of the Compressive Strength of Spruce Struts of Rectangular Cross Section and the Derivation of Formulas

Suitable for Use in Airplane Design, by James E. Boyd.

The Effects of Sulphur and Phosphorus on the Properties of Steel, a bibli- ography on the subject for the Committee on Phosphorus and Steel in Steel. Fireproof and Transparent Airplane Wing Coverings. Letter Circular YII-1-12. Report of Dimensions and Tolerances for the Cross Section of Streamline

Stay Wire. Letter Circular VII-1-16. The manuscript for the circular " Compiled Tables of Physical

Properties of Materials " is now ready for the printer. These data

have been submitted to a number of engineers and others for criticism

and revised in accordance with the suggestions which have been

received. The requests for these data indicate a need for this in- formation which is supplied by no other publication at the present

time.

CEMENT, CONCRETE, STONE, GRAVEL, AND SAND.

This section is concerned with the investigation and testing of

cement and allied materials for construction purposes, the development of new methods of testing, improvement of apparatus for test- ing, the preparation of specifications covering cement and similar

construction, development of new uses for cement products, the dis- tribution of knowledge concerning their use, and with the design

and fabrication of cement, concrete, and similar structures. The

Bureau acts as a testing laboratory for practically all the cement

used in the Government's construction work, as far as its facilities permit.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 189

Test of a Concrete and Hollow-Tile Floor Reinforced in Two Directions.

It is believed that the test described below is the most elaborate one of a full size floor structure ever carried out. The expense of

the work was largely borne by J. J. YVhitacre of the Whitacre-Greer

Fireproofing Co.. of Wavnesburg. Ohio.

The purpose of the test was to obtain data which would afford a basis for the design of a two-way reinforced concrete and hollow tile floor system. Mathematical analysis indicates the necessity for

stronger construction than that which has been found satisfactory

as the result of tests. This has led to a controversy- between those

who placed full confidence in analysis and those who believe in

ignoring the analysis and designing solely on the basis of test results. The test here described was planned so as to eliminate the

sources of dispute which have placed test results in question and

have thus led to the above-mentioned controversy.

For the purpose of obtaining the data desired a large slab was

constructed upon which strain measurements were taken on approximately 900 gauge lines in the reinforcement, 500 gauge lines in

the concrete and 75 gauge lines in the tiles. Deflection was observed

in 40 places.

The slab is 117 feet G inches long and 50 feet wide, and is divided

into IS panels. Six of these panels are 16 feet square, six are 16

feet by 19 feet 3 inches, and six are 16 feet by 22 feet 6 inches.

These panels are supported by reinforced concrete girders, which

are generally 12 inches wide. The slab, whose total thickness is 6

inches, is made up of 6 by 12 by 12 inch clay tiles laid in such a manner as to form rows in two rectangular directions with 4-inch

ribs of reinforced concrete between each two rows of tiles. The ends

of the tiles were left open, allowing a small amount of concrete to enter the cells so that they form an integral part of the slab. Each

concrete rib throughout the slab has as reinforcement one -J-inch plain round bar extending the full length of the rib. The slab Avas first loaded with a uniformly distributed load until

the yield-point stress in the reinforcement over the edges of the

panel was reached. The load was then shifted to give higher

stresses at other places in the slab. Although it had been planned

to apply enough load to cause failure it was not possible to pile the

load high enough to bring about complete destruction of the slab. Approaching failure was indicated by the fact that the stress in the

reinforcement had passed the yield point in many places. No in- dication of compression failure in the concrete or in the clay tiles was found. In such constructions it is generally assumed that the

tile is only a space filler which lightens the construction, but it was

found here that it contributed in an important manner to the strength

of the structure. With respect to the manner in which the stresses were distributed

through the slab and with respect to a comparison of the behavior

of square panels and oblong panels the test confirms reasonably well

the results of the best mathematical analyses. The test, however,

showed much greater strength in the slab than the best analysis

would indicate.
190 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

The report of the test has been completed and will be combined

with a mathematical analysis of this type of slab to be published as

a technologic paper.

Tests of Bond Resistance Between Concrete and Steel. This investigation comprises tests made for the concrete ship

section of the Emergency Fleet Corporation on (a) "pull-out"

specimens in which steel bars were coated with various materials for

protection against corrosion, and {b) on beams in which the uncoated reinforcing bars were spliced by lapping at the center of

the span.

The "pull-out" tests consisted in measuring simultaneously the

amount of load and the amount of slip during the pulling out of

coated bars which were embedded axially in concrete cylinders having a diameter of 6 inches and a length of 12 inches. The tests in- dicate that, in general, the use of a coating to protect a bar against

corrosion reduces greatly the bond resistance between the concrete and the steel. The beam tests Avere made to determine how great a length of lap

is required when tension reinforcement is spliced by lapping and

without any other connection between the separate bars than that

which is afforded by the bond between the concrete and the steel. The test results indicate that for a concrete of one part cement and

two parts aggregate (having a strength of about 5,000 pounds per

square inch), a lap of about 48 diameters of the bar is necessar}^. It follows that for leaner concretes a greater length of lap would be

necessary. These figures assume that the yield point of the steel is reached at a stress of 40,00.0 pounds per square inch.

Pouring and Pressure Tests of Concrete.

These tests were made in connection with two minor investigations

carried out at the Bureau of Standards for the concrete ship section

of the Emergency Fleet Corporation. They were undertaken with

the object of obtaining data useful for design under the special

conditions involved in the construction of concrete ships.

The pouring specimen used was a slab 6 feet high by 6 feet wide

and 4 inches thick, having a mass of reinforcement designed to reproduce conditions such as would occur in pouring the shell of a reinforced concrete ship. The reinforcing bars were placed so close

together as to afford little room for passage and the form was further constricted by strips of wood nailed on the sides. The concrete was poured in three lifts, with the form standing in a vertical

position. The test showed that under the adverse conditions repre- sented by this test it was possible to obtain a smooth surface and a high strength of concrete. For the measurement of pressure a specimen nearly 17 feet high was used. Pressure of the concrete against the forms was measured

at various heights. The results indicated that the maximum pressure

against the forms during the pouring of the concrete was equivalent

to that of a liquid weighing 124 pounds per cubic foot. The maximum pressure was found to be that due to the head of concrete, which

existed at the end of about 40 minutes after the beginning of pouring.

After that time the pressure at the bottom of the form gradually

decreased in spite of an increasing head of concrete.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 191

Compressive Strength of Concrete in Flexure.

A paper on this subject has been prepared, in which use was made

of hitherto unpublished test results obtained by (a) the U. S. Geological Survey in an extensive investigation of reinforced

concrete in St. Louis from 1905 to 1908; (6) the Bureau of Standards, at Lehigh University, in connection with investigations for the

concrete ship section of the Emergency Fleet Corporation; (c) Lafayette College, at Easton, Pa.

Previous to this paper few results have been published of tests in

which failure of concrete beams was due to crushing of the concrete. The paper shows that with concrete of the quality ordinarily assumed

to be furnished for construction purposes there is much greater

strength in compression than in tension. The indications are that

for the design of reinforced concrete beams the working stresses in

compression might safely be made considerably higher than those

used at present in standard practice, providing that a little greater

uniformity in the strength of concrete can be secured than has been

the case in the past.

Volume Changes in Mortars and Concretes.

Investigations carried on in this field during the past year have

yielded a number of results of considerable value. With the Bureau's

present equipment, refined methods of measurement are possible,

and as a result, accurate measurements of volumetric changes that occur in mortars from the very time of making have been obtained.

During the present year a number of practical problems have been

dealt with, such as the determination of initial and total volume

changes in mortars and other standard mixtures, hydration effects, effects of retempering, and influences of various types of bases. Tests have shown that the usual rather severe volumetric changes

that may occur in mortars suitable for stuccos during the period of

setting may be entirely eliminated by proper contr'ol of moisture

conditions during this period, so that the danger of having destructive cracks develop because of these initial volumetric movements

will be largely or wholly avoided. The effect of retempering (that

is. the remixing, or the continual mixing of a mortar for a considerable period before placing) was studied because of the question that

exists as to whether retempering improves or impairs the quality

of the mortar. Results indicate that retempering causes the occur- rence of greater volumetric changes, so that in this respect at least

it is not to be recommended. Experiments made with mortars cast in forms Avith various types of bases have given valuable information as to the influence of the condition of the base itself on volume

change. It has been found possible with the use of an absorptive

base to eliminate in standard mortars practically all of the usual

shrinkage that occurs during the period of setting and to reduce

by approximately one half the later volumetric changes. This in- formation is of particular importance in stucco and plaster work

for it suggests the necessity for control of " suction " if the vol- umetric change in the applied coat is to be reduced to a minimum.

As indicated above, the laboratory work has been confined largely

to mortars and a report on this phase of the investigation will be

prepared during the coming year. A month's field work has also
192 K.EPOBT OF DIRECTOR OF BUREAU OF STANDARDS.

been included, partly in connection with the reinforced concrete

investigations of the Section and partly in measurements on test slabs of the Coleman Dupont highway in Delaware. The latter Avere started in 1915 and will possibly be continued for another year

before a report on the studies of these slabs will be prepared.

Fineness of Cement and Other Materials.

Under this heading are included investigational work in con- nection with the study of properties of very finely divided materials,

the standardization of testing sieves, and the preparation of samples of cement of standard fineness. Air Analyzer.—This apparatus was developed some years ago for

determining the extreme fineness of cement and other pulverized

materials in a region beyond the reach of mechanical sieves. Aside

from minor improvements in" the accessories no changes have been

introduced in the form of this apparatus, nor in its manipulation.

During the year mechanical analyses have been made with the

analyzer and sieves on samples of cement, paint pigments, ground

silica, ground feldspar, foundry and other sands, gravel screenings,

clays, and metal powders. One investigation, carried out for the

paper section of the Bureau, involving much time and labor, was

a comparison of the mechanical analyses of twelve samples of English and American clays, to determine the relation of fineness to quality as paper fillers. Standard Cement Sieves.—During the year fifty-six 200-mesh

sieves were standardized. In the annual report for 1918 it was noted

that it had become difficult to obtain 200-mesh sieves that would meet

the standard specifications. During 1919 there was an improvement

in the quality of the sieves submitted to the Bureau for standardization. On the whole this improvement has continued and sieves meeting the standard specifications may now be obtained from a number

of manufacturers.

A comparative study has been made with the chemical division of

the Bureau on the standard method of making fineness determinations (of cement) and the wet sieving process as used in determining

the fineness of paint pigments. Owing to the fact that in the latter process 3-inch sieves are used in lieu of 8-inch sieves, and a 5-gram

sample in lieu of 50-grams, the results obtained are not directly comparable, but the tests established the fact that the standard method

for cement is of the same order of accuracy as the wet process, and

simpler in that it does not involve the use of chemical equipment.

The studies also established the need for correction factors for the

3-inch sieves, if used in the fineness determinations of materials of

medium fineness, such as portland cement. ' Some attention has been given also to measurements of particles

passing various standard 200-mesh sieves in a search for a further

check upon the quality of the sieves, but owing to the limited accur- acy of these measurements, unless taken in large numbers, the

method is not promising.

U. S. Standard Sieve Series.—Specifications for a new series of

standard testing sieves have been developed in cooperation with the

weights and measures division of the Bureau. In connection with

the standardization of these sieves, the present specifications are based
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 193

only upon average measurements of openings and wire diameters,

with, certain tolerances upon these averages and upon the maximum

openings. It is recognized, however, that appreciable differences

in sieving values of sieves meeting these specifications will exist,

particularly in the finer sieves, and data will be obtained as the new

sieves come into general use as to the magnitude of these differences

in sieving values, and the need of correction factors to be applied

whenever results of the highest obtainable accuracy are required.

At the present time all sieves finer than the No. 80 submitted for

certification as to conformity with the new specification are beingtested for sieving values with the standard cement samples, and

plans are being considered whereby a more suitable material may

be made available for this purpose.

Two manufacturers of wire cloth are now furnishing sieves ac- cording to the specifications for the U. S. standard sieve series, and

a third manufactures a series of testing sieves of which the majority

nominally conform to these specifications.

Standard Samples.—The Bureau prepares and keeps on hand for

issue standard fineness samples of cement for checking up 200-mesh

sieves. They are supplied in two degrees of fineness and are issued

in sealed glass jars, each jar containing about 160 grams, enough for

three 50-gram sieve tests. Each sample is accompanied by full di- rections for its use. A nominal price of 50 cents, sufficient only to cover the cost of preparation, is charged for each sample. With

these samples 200-mesh sieves may be compared with the fundamental standards and correction factors obtained. These samples

are also used by the Bureau in checking up its own sieves and in

the standardization of 200-mesh sieves submitted for certification. On account of the exhaustion of the Bureau's old supply, it was

necessary in the early part of the year (1920) to prepare new standard samples. The new samples are : 46f-80.5 per cent passing the

200-mesh sieve, and 47c-89 per cent passing the 200-mesh sieve. Stucco.

Previous work in this investigation has been supplemented by field inspections to study climatic effects upon the durability of stuccos. Structures were examined in Georgia, Florida, Alabama, Louisiana,

Tennessee, Kentucky, Ohio, Illinois, Wisconsin, Minnesota, and California. The data obtained indicate that durable and satisfactory

stuccos can be produced in any section of the country, provided the

work is in the hands of those who are familiar with the requirements

of this class of construction and know the limitations of the materials

entering into it. Stucco troubles may be attributed to two main

causes, (1) cheapness of construction, which precludes the use of

proper materials and methods, (2) lack of knowledge of fundamental

requirements, in which both architects and plasterers are at fault. Reliable information in regard to stucco construction is contained

in the Recommended Practice for Portland Cement Stucco, published

this year by the American Concrete Institute and based upon ex- perimental work and field inspections conducted by the Bureau.

Concrete Tanks for Oil Storage.

An investigation of the suitability of concrete tanks for oil storage was undertaken for the Navy Department and the Shipping Board

10613—20 13
194 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

in 1918. Because of the subsequent rapid introduction of this type of

tank for oil storage in the industries, the investigation has been con- tinued and probably will extend into the next two or three years. The qualitative storage tests of 18 different oils, described in the

last annual report, have now been under way for two years. None of

the tanks have been affected by the mineral oils, and of the animal and

vegetable oils only coconut and lard oil have shown visible disintegrating effects. In addition, the raw linseed and neats'-foot oil have

attacked to some extent the test cylinders immersed in them.

The quantitative tests referred to in the annual report for 1919

have been supplemented by an extensive series of tests of 1 : 1-1- : 3 concrete tanks, which are representative of the construction of oil tanks for industrial purposes. These tanks have been filled with

mineral oils covering the entire range of fuel oils and the rates of

seepage determined. After the rates of seepage became practically constant under low pressure, a tank which represents typical behavior

for each oil is put under a pressure head of 35 feet and the rate of

loss determined under these conditions. These tests will later be used

as a basis for determining the relative merits of various recommended

oil-proofing treatments. As the test tanks used in the oil-storage investigations have proven

very satisfactory for permeability tests, certain comparisons have

been made on various concretes for water-tightness. It was found

that 1:2:4 concretes gaged with 8, 9, and 10 per cent of mixing water were more permeable in the order named, although all these tanks were bone dry on the outside when tested with water under 35 feet head. Comparison of 1:2:4 concretes made with the centrifugal

mixer and a mixer of the open-pot type showed permeabilities of the same order of magnitude.

The year's work included a three months' field survey of concrete tanks in use for storing fuel oils for industrial purposes, and in the

oil fields for storing crude oils. Concrete tanks without special treat- ment are proving successful for the storage of oils as light as 40°

Baume, and in several cases oil-proofed tanks are apparently re- taining gasoline with negligible losses. One of the chief advantages

of concrete storage is the fact that the tanks are built below ground

and thus avoid the wide temperature variations which are sources of

trouble in steel tanks above ground. In concrete oil storage the fire hazard is minimized, and by designing the roofs of tanks for definite

loads valuable space in the factory yard is made available for other

purposes. The fundamental requirements in successful concrete tanks

and reservoirs are careful attention to foundations and to concreting

methods, which will insure the continuity and impermeability of the concrete itself. Automatic Freezing and Thawing Apparatus.

This apparatus, designed for the purpose of making weathering

tests on building stone, concrete, brick, and similar building materials,

has been modified from the original form in order to give more uniform conditions throughout the test. In the present form the speci- mens are thawed in water, which also serves to control the degree of

saturation. This form of the apparatus promises to give results which can be correlated with actual weathering in structures and

reduce the time and labor of the test to such an extent that it will be
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 195

practical to make a large number of freezings under normal conditions of saturation.

Grading of Indiana Limestone.

The work undertaken for the purpose of establishing a more definite means of grading Indiana limestone has been completed, with the

exception of weathering tests, which have been held up for the completion of the freezing apparatus. The results indicate much over- lapping of physical properties from one grade to another, and from

the present data it appears that a system of grading based on such

properties as strength, absorption, specific gravity, etc., would not

be more satisfactory than the present basis, viz, that of texture. Freezing Tests of Sandstone.

Several samples of sandstone have been experimented with in the

freezing test. Some of these have withstood 300 freezings without

showing visible effects, while others were completely disintegrated

by 100 or less. All samples showed a loss in strength clue to freezing,

and the percentage loss appeared to depend principally on the original strength of the material. In a general way a relation was indicated between the loss in compressive strength and the percentage

of absorption of the materials, viz, those having the highest absorption suffered the greatest loss in freezing, but the relation was not so

clearly marked as that between the original strength and the loss in

freezing.

Laboratory Tests in Relation to Durability of Building Stones.

In order to compare the results obtained in the laboratory weathering tests with actual weathering numerous structures were examined

which showed the effect of exposure for various periods of time. The

materials studied included 8 varieties of limestone, 13 varieties of

marble, 11 of sandstone, and 12 of granite. Several buildings, monuments, etc., were inspected which were over 100 years old. Only a few granites were found that showed appreciable decay, and some

sandstones appeared to be almost as resistant, while most types other

than the granites showed considerable disintegration after 50 years'

exposure. With sandstone the actual weathering appears to compare

very well with the results of frost-action tests made in the laboratory.

With limestone the actual weathering seems to be a combination of

frost action and chemical solution, which will require the modification

of the present laboratory test to give comparable results. With marble the principal weathering agent seems to be that of chemical solution, but frost action is important at bedding planes and other places

where water may readily penetrate the stone. The few cases of decay

in granite make the study of the causes uncertain, but thin exfoliation

of the surface seems to indicate that the chief element of destruction

is that of temperature changes alone. Hence it appears that a large

amount of experimentation will be necessary to establish a test that

will give results on all types of stone to compare with actual weathering.

Discoloration Tests. Tests are in progress to determine the cause of staining and

efflorescence on the surface of limestone structures. Twelve limestone panels, each approximately 3 feet square, have been erected on
196 REPORT OF DIRECTOR OE BUREAU OE STANDARDS.

the roof of one of the Bureau's buildings, in which the stone was set with normal Portland cement, white Portland cement, slag cement,

natural cement, and lime mortar. All of the panels have red-brick

backing, and different processes of waterproofing have been used in

a part of the panels. These panels were erected in September, 1919,

and efflorescence soon appeared on the surface of all the panels,

which increased in amount during the Avinter months. Early in the

spring the greater portion of this disappeared, due to cleaning by

heavy rains, and has not reappeared in prominent quantities. The

very slight amount of staining which has occurred does not seem to bear any relation to the types of mortar used.

These exposure tests are supplemented by leaching tests in the

laboratory which are designed to differentiate between the staining

due to soluble salts in the stone itself and that due to mortars. Durability of Cement Drain Tile and Concrete in Alkali Soils and

Waters.

Field investigation was resumed in 1919 after three years suspension during the war. This investigation, started in 1913, includes

the installation of 21 series or types of cement drain tile in workingdrains in eight localities where large quantities of alkali salts are found in the soil. These drains were installed at Garland, Wyo.

;

Fort Shaw, Mont. ; Sunnyside, Wash. ; Yuma, Ariz. ; Eoswell, N.

Mex. ; Montrose, Colo. ; Grand Junction, Colo. ; and Huntington,

Utah. For purposes of comparison, drains were installed in the

humid region where no alkali is found, at Crookston, Minn., and

Columbia, Mo. Sufficient quantities of each type of tile are installed

in each drain to permit extending the tests over a period of 20 years

or more. In addition to drain tile large groups of concrete blocks were molded in 1915 and installed in alkaline sloughs at Garland,

Wyo.; Fort Shaw, Mont.; Sunnyside, Wash.; Fallon, Nev. ; Mesquite, N. Mex.; Montrose, Colo.; and Grand Junction, Colo., and

Newell, S. Dak. A large lot of blocks 10 by 10 by 30 inches long- were molded at Denver in the proportions 1 : H : 3 and 1 : 2J : 5, and

some were shipped to each of the above places. At each place

similar blocks of the same proportions were molded, using the

materials in common use for concrete work in that locality. The

wide variation in the cements and aggregates used, together with

the different conditions to which they are exposed, permit valuable

observations to be made as to the durability of various qualities of

concretes, all results being tied together by observations of the

Denver blocks under similar conditions.

While this investigation is by no means completed, the results of

tests and observations to date permit several definite conclusions to be drawn and point out logical steps to be taken in extension of the

investigation. During the spring of 1920 a field investigation was made of the conditions of various concrete structures in the prairie

Provinces of Canada. Observations made on this trip strongly

emphasize the conclusions already derived from investigations in the

States and indicate that aside from the more severe weather conditions the alkali problem is identical with that in this country.

The following comments and conclusions seem to be justified by

the results of the investigation, but will be subject to modification

and enlargement as more data become available.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 197

1. Sulphate waters as a type appear to more seriously affect concrete than chloride or carbonate waters.

2. Severity of action on concrete in sulphate waters appears to Vary with concentration of soluble salts.

3. Under given conditions of concentration durability of concrete appears to vary directly with richness of mix and impermeability of mass. The latter property is partially dependent on the richness of

mix and indications are that permeability alone is the best criterion

of durability.

A. Even though certain qualities of concrete may be identified and

specified, which will safely withstand any given degree of concentration, it will probably not be possible to discover what maximum

concentrations may later be found or developed in any district. Experience has shown that analyses of water samples taken at the outlet or intermediate points in a drain give little indication of what

concentration may be encountered a few feet away. In 1919 at one

block installation subsoil water in the ground just outside the block

site showed a concentration of 0.51 per cent soluble salts, the surface

water a few feet distant surrounding the blocks had a concentration

of 3.31 per cent and a small pond on the side opposite the location

of the first sample had a concentration of 0.93 per cent. Similar

conditions have been found in tile drains.

5. If concentrations are high even the best quality of concrete may be attacked. Where unusually high concentrations are found

in advance of construction, every possible precaution as to thorough

drainage should be employed so as to keep alkaline ground waters

away from the structure.

6. Since all results indicate that the quality most needed for ex- posure to alkali waters is impermeability it seems that progress can

best be made in the investigation by a series of laboratory tests to determine the variations in materials and methods of manipulation

which affect this property. This work can be done most economically, quickly, and efficiently in the laboratory, to be later followed

by duplication of the most promising concretes in the field. It is proposed to follow this plan in the continuance of this investigation.

Preliminary Examination of a Proposed Site for a Cement Plant.

In compliance with a request of the State officials of Mississippi,

a representative of the Bureau visited Oklona, Miss., for the purpose

of making a preliminary examination of the State's property at that place relative to its suitability as a location for a cement plant.

The submitted report gave the results of general observations and a number of chemical analyses of the available raw materials Avith

their application to the manufacture of Portland cement. Also, some

general data were given on the cost of erecting and operating a cement plant, together with a brief discussion of the more important

conditions upon which largely depends the degree of success attained

in undertakings of this kind.

Measurement of the Consistency of Concrete Mixtures.

The " flow table,'' developed in the concrete laboratory in 1919

and described in the last annual report, has been used continuously

in all concrete tests and investigations, and is now considered an in- dispensable part of the laboratory equipment. A paper by G. M.
198 REPORT OF DIRECTOR OE BUREAU OF STANDARDS.

Williams describing this apparatus in. detail and its application to concrete testing was published in the Engineering News-Record of

May 27, 1920. The flow table has been found applicable to the

measurement of other properties of concrete than consistency or

flowability, e. g., the measurement of the time of set of mortars and

concretes can be determined by testing the molded mixtures at regular intervals after mixing; the harshness of a mix, or its tendency to segregate, can be compared with that of other mixtures

containing different proportions of fine and coarse aggregates or additions of finely divided materials to improve working quality;

from preliminary tests of concrete containing different proportions

of given materials, in which the consistency is controlled, strength

may be predicted for all combinations of ingredients. The utility of

the flow table for controlling and measuring consistency has been

demonstrated at a large cement brick plant in New York, where

the type of machines and the methods of handling require control

of this factor within narrow limits. Another practical application

of the instrument was shown where an accelerator was being used

in a concrete floor topping to shorten the time required for finishing.

The time of set of the treated mortar was in this case found to be

one-half that of the untreated.

Centrifugal Concrete Mixer.

A very extensive series of tests, extending over a period of several

months, was made to compare the mixing action and the concrete produced in a new type of centrifugal mixer with that produced in an open-pot type widely used in commercial and laboratory work.

The centrifugal mixer, of one-half yard capacity, consists essentially

of a horizontal bowl which can be rotated about a vertical axis

at 70 to 80 r. p. m. The contents of the bowl are thrown outward

and upward by the centrifugal action, and are deflected back in

streams to the center of bowl by four fixed deflectors attached to the stationary frame. To discharge the mixer one of the deflectors

is slightly raised, permitting the contents to flow over the rim of

the bowl into a hopper or chute.

The comparisons were first made on batches similar in ail respects,

but it was found that the severe grinding action in the centrifugal

mixer reduced the fine aggregate to such an extent that decidedly

stiffer consistencies were obtained from this machine. Hence later comparisons were made in which the same consistencies or flowabilities were maintained by additions of the required amounts of water. The results of the tests may be briefly summarized as follows

:

1. The work done on the mass of concrete by the centrifugal mixer

is greatly in excess of that done by the laboratory mixer. The

velocity of flow in the former is such as to produce a ball mill action,

the coarse aggregate grinding the fine to a remarkable extent even

in a mixing period of two minutes. The increase of fine material

thus produced is such as to require from 5 to 10 per cent more water

to maintain the same degree of flowability as that in a similar mix

in the laboratory mixer.

2. The results of the tests indicate that if similar batches of aggregate, cement, and Avater are mixed in the same proportions in the two

types of mixers, the strength of the concrete produced by the cen- trifugal mixer is about 20 per cent higher, on the average, than that
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 199

mixed in the open-pot mixer. As explained in the preceding paragraph, however, this additional strength is attained at a sacrifice of

flowability, which detracts from the apparent superiority of the

centrifugal mixer in comparative tests. When similar batches were mixed in the two mixers with an adjustment of the water content to

yield concretes of the same consistency or flowability, the strengths were found to be more nearly eqiial. The average of all comparisons on this basis indicate the concrete mixed in the centrifugal mixer to be approximately 7 per cent stronger than that from the open-pot

mixer.

3. The excessive mixing action of the centrifugal mixer is an advantage in one important respect. Thorough mixing of a batch

under normal conditions can be obtained in 15 to 30 seconds, and in

general the strengths obtained from the 15-second mixes are as high

as those of longer periods. It appears that the amount of mixing

action per reA^olution of the bowl of the two mixers is nearty equivalent, and in this respect the output of the centrifugal of properly

mixed concrete is much greater than that of the laboratory type.

Accelerators.

Preliminary work on " Cal " (calcium oxychloride) as an accel- erator, described in the last annual report, has been supplemented by

further work on mortars and concretes, in comparison with calcium

chloride. The investigation as outlined has been completed, and the

results are contained in a paper, " Effects of Cal as an Accelerator of

the Hardening of Portland Cement Mixtures," which has been submitted for publication as a Technologic Paper. In brief, the effects of this material are approximately the same as those of calcium

chloride—it tends to correct unsoundness and quick set in abnormal

cement, it decreases the time of set of normal cements by approximately one-half, it hastens the early hardening of mortars and concretes, and has the advantage over calcium chloride in convenience

of handling.

In view of the unusual claims made for a new proprietary waterproofing and hardening liquid placed on the market at a very high

price and widely advertised during the past year, an extensive series of tests was made on mortars and concretes in which the effects of this

material were determined. As preliminary chemical analysis indicated the liquid to be a solution of calcium chloride in water, the

comparisons were made throughout with plain water and solutions

of commercial calcium chloride of equivalent strength. Very complete chemical and physical tests indicated that the commercial

chloride and the proprietary liquid were essentialty the same both

in composition and in their action on mortars and concretes. Service Tests on Concrete Floors.

These tests have been in progress for almost two years, and have

proven to be of considerable value in furnishing data concerning

the relative value of the principal commercial compounds sold for

this purpose as well as a few treatments that are not sold under

trade names, and are hence more economical.

The treatments may be divided into three types, viz, chemical

hardeners, surface coatings, and waxes. The first includes sodium
200 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

silicate solution, magnesium fluosilicate solution, aluminum sulphate

solution, and zinc sulphate solution. The second class consists of

hard drying paints and varnishes, and under the third class are two

distinct wax treatments, one applied in solution and the other in a molten condition.

All chemical hardeners have given good results. Two of the

treatments may be readily prepared and applied by inexperienced

persons at small expense. . These are sodium silicate and aluminum

sulphate. The surface coatings are believed to be the most effective for entirely eliminating dust, and are desirable where delicate machinery exists. which would be damaged b}' very fine particles of

grit. However, these are expensive and may have to be replaced

under heavy traffic as often as once a year. The wax treatments have

not proven very satisfactory in these tests. The one which is placed

in a molten condition gave a good surface to a rather poor floor for

a period of one year or more, but its cost is too great to justify its frequent renewal.

Effect of Storage on Cement.

The deterioration of cement which has been in storage for a long

time or has been exposed to extreme weather conditions has been

lepeatedly brought to the Bureau's attention during the past year. During the war large stocks of cements were gathered for construction work at various camps, and due to delays some of these stocks were stored for long periods before being used. Tests of such ce- ments in concretes indicated that the concrete-making qualities of

Ihe stored material had been so reduced that concretes having only

30 to 50 per cent of normal strength at 28 days resulted, although the

material originally met the standard cement test requirements. Generally such cements in concretes will regain a portion of the lost strength at later periods, but experience on several jobs has indicated that this regain can not be depended upon, and such cement is particularly dangerous for use in cold weather work. Although

meeting the laboratory specifications for setting time, concretes made

with heated aggregates and protected for weeks from freezing have

failed to harden properly with the result on one job that a large

structure had to be removed and replaced. In connection with tests of old cements it has developed that the mortar tensile tests do not

indicate properly the low cementing qualities of such cements when

used in concrete and tested for compressive strength. The entire

subject demands further investigation at the earliest opportunity.

Loss of Water in Molds.

Several series of tests have been made to determine how the compressive strength of concrete test specimens is affected by permitting

mixing water to escape from 6 by 12 inch iron cylinder molds during the first few hours of hardening. The molds in use consist of

6-inch diameter black iron pipe split longitudinally with an element

about three-sixteenths inch wide removed. By means of lug angles

and bolts with winged nuts the slot may be closed previous to fill- ing. Such a seam is not water-tight in all cases. This, as well as the unsealed base, permits small quantities of mixing water to escape,

especially from the wetter consistencies. The results of the tests indi-
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 201

cate that loss of water under these conditions has no effect in increasing strength different from that produced by the natural settlement

of similar mixtures in water-tight molds, and the consequent expulsion of water at the top.

Concreting Trouble in Cold Weather.

Inspection was made to determine the cause of vertical cracks appearing in the columns of a large concrete ice-storage house under

construction in Philadelphia. The construction consisted of heavy concrete columns designed to support the steel roof trusses with the space

between the columns filled in with heavy concrete curtain walls whose

inside faces were flush with the inside faces of the columns. Cracks

did not appear at the junction of wall and column as might be ex- pected but were confined to the exterior faces and sides of the column.

Tests of the materials used indicated that all were normal in quality

and that the cracks were probably due to slight expansive movements

in the vertical sheathing of the wood forms in contact with the concrete surfaces. Owing to the low temperatures at the time the work

was under way, the rate of hardening of the concrete was naturally

slow and slight expansion or swelling caused by absorption of water

by the sheathing, probably aided by freezing of the sheathing, caused

slight movements which were transferred to the concrete surfaces

after the concrete had lost its plastic condition and before sufficient strength was developed to overcome the slight bond between the concrete and wood form.

Field Tests of Concrete.

Tests which have been made in the laboratory of concretes pre- pared on construction jobs in the field emphasize the need of a well- planned program of field tests on all important concrete work. It is customary in advance of work to make a few strength tests with the

aggregates which are to be employed, especially if the engineer or contractor is unfamiliar with aggregates from that particular source, but very rarely are specimens of concrete later taken from the work

for test. It is commonly assumed in design that a 1:2:1 proportion concrete will have a compressive strength of 2.000 pounds at 28

days, but our experience has been that more generally values of 1,200

to 1,400 pounds are obtained. Using the flowabilities which must be

employed on most work it is often impossible even in the laboratory

to attain 2,000 pounds with the specified proportions. Most engineers' and architects' ideas concerning the strengths of concretes have been obtained from the results of laboratory tests made with- out consideration of the controlling factors which are met with in

the field. More attention to the results which are actually being

obtained on the work may in many cases cause serious alarm, but the

outcome should be an improvement in the quality of field concrete and a better understanding on the part of all concerned of the diffi- culties which must be met and overcome " on the job."

Wet and Dry Aggregates.

On most concreting jobs sand and gravel are proportioned by

volume. While the bulking effect on the reduction in weight of sand

per cubic foot due to the addition of water up to certain limits is
202 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

well understood, the actual effect on the quantity and cost of concrete produced, caused by variation in the amount of moisture in the sand

is not so well known to engineers and contractors. Using the same volume proportions, dry sand results in a greater bulk of wet concrete than does wet sand, hence more cement will be used per cubic

yard of concrete when wet sand is employed. This condition is brought about automatically and can be controlled and modified only

by the use of a greater bulk of sand when wet sand is used. Data

obtained on this subject indicate that the excess quantity of cement

involved by using wet sand instead of dry may amount to more than

10 per cent, and the additional strength may be considerably greater

than this. The matter is interesting, not only from its economic importance, but also from the fact- that it suggests the advisability of

determining more fully the effects of wet aggregates on compressive

strength, facility of mixing, etc. Oversanded Mixes.

Some work has been done with " oversanded " concrete mixtures.

By " oversanding " is meant the use of a larger proportion of sand

to coarse aggregate than is usually specified. Specifications, especially in structural work, usually call for a 1:1-^:3, 1:2:4 to 1:3:6

proportion in which the sand volume is 50 per cent of that of the

coarse aggregate. In " oversanded " mixes the ratio of sand to coarse aggregate may be increased to 0.6, 0.75 or even 1, reducing the volume

of coarse proportionally so that the volumes of sand and gravel re- main constant. The advantage of " oversanded " over the usual mixtures were as follows: (1) "Oversanding" results in an easy working, more plastic mixture which shows no tendency to segregate when

using wet consistencies. Owing to the relatively large volume of

mortar, the flowability of the mortar in an " oversanded " mix is less than in a normally sanded mix, although the flowabilities of the tsvo concretes are equal. (2) Slightly less cement is used per cubic yard

of wet concrete. (3) Compressive strengths will be higher for the

" oversanded " mixtures, in case the sand is not too fine. Tests with

Potomac Eiver sand indicate that " oversanding " may be beneficial

up to 1 : 3 : 3 in place of the usual 1:2:4 for regular run gradation.

With other lots of sand the desirable limit of oversanding was found

to be 1 : 21/2 : 3% and with some " oversanding " resulted in slight

strength decreases.

New Experimental Cement Plant.

With the transfer of the investigations dealing with the production

of Portland cement from Pittsburgh to Washington, it was thought

advisable to enlarge the experimental cement plant. Consequently

larger crushing and grinding machinery and a new rotary kiln 3 feet in diameter and 30 feet long were installed. One of the first investigations outlined for the equipment is the burning of a number of domestic magnesites to plastic magnesia. This will be followed by the

burning of some Portland cement mixtures to which various fluxes have been added to reduce the clinkering temperature.

Magnesite Deposits.

During the year a representative of the Bureau visited several of

the magnesite mines in California and Washington where the ore is
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 203

or may be obtained principally for the plastic trade—especially for

flooring and stucco. The reports somewhat current in the East to the effect that the amount and the quality of the ore available in these

localities is small and poor are without any basis of truth. On the

other hand the quality of the amorphous ore is excellent, and while

the crystalline has too much color for white products, yet it is eminently satisfactory for the greater number of uses to which plastic

calcined ore is put. The quantity of both kinds is tremendous and

should not give the user any cause of uneasiness as to shortage for

ye&rs to come.

Sorel Cement.

Better progress has been made in the investigations dealing with

Sorel cement (magnesia-oxychloride) during the year than was

previously the case. This has been due to acquiring a knowledge of some of the effects of the unknown variables, which has rendered it possible to lay out a more advantageous program for attacking the

problem. Thus it was found desirable to confine the work to magnesites burned in the laboratory to determine both the effect of

time and temperature of burning and size of material entering the

kiln. Thus far the results obtained with material burned in an elec- trically heated rotary kiln show that all three of these variables very

decidedly change the properties of the resulting magnesia both as to strength and constancy of volume. With the completion of a series of burns in this kiln it is proposed to burn a number of domestic

magnesites under certain conditions in the 3-foot by 30-foot rotary

kiln of the Bureau. Enough calcined ore will be obtained to permit

of making not only the usual laboratory specimens but also several

service panels of stucco and flooring.

Miscellaneous Tests and Investigations.

The Bureau has cooperated throughout the year with the Government engineers in charge of the construction of Key Bridge between

Georgetown, D. C, and Bosslyn, Va., in numerous tests of cement,

aggregates, and concrete taken from the work.

At the request of the office of Public Buildings and Grounds an

inspection was made in May of the Lincoln Memorial and a report

rendered on the condition of the marble in the structure. An extensive series of tests on a commercial Portland cement of

high fineness was carried out, supplementing the preliminary work

described in the last annual report. The results confirmed previous

data in that very large increases in strength were obtained in concretes as compared with normally ground cement. In Connection

with these tests it is interesting to note that none of the accelerators

of the calcium chloride type are as effective in producing early hardening of concrete as the additional fineness (approximately 12 per

cent in this case) of the cement itself. Moreover, the advantage in

strength from the finer cement is maintained indefinitely, whereas

the effect of the accelerators is generally lost after the 28-clay period. Tests of blast furnace slag as an aggregate for concrete, made at different times during the past few years, have been compiled. A

study of the results indicate that so far as the material tested is con- cerned slag produces a concrete which is the equal of gravel concrete.
204 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

There were no signs of disintegration from any cause up to one 3-ear. Slag screenings, because of their lack of fine material, do not produce

easily workable concrete when used as fine aggregate. Addition of

fine sand or other fine inert material tends to improve this quality.

Paper molds have been furnished by the Bureau in a number of in- stances to facilitate the taking of samples of concrete from various

Government projects. Field samples of concrete, aggregating some

hundreds of test specimens, have been submitted by and tested for the

following agencies: Chief of Transportation, War Department, in

connection with construction of concrete vessels ; public works officer,

Philadelphia Navy Yard, in connection with construction of the new

dry dock at League Island ; contractors for the Quartermaster Terminal, Philadelphia; board of water commissioners, Hartford, Conn.;

engineers in charge of Key Bridge, Washington, D. C, as above re- ported.

The Washington laboratory tested 296 samples of miscellaneous

materials submitted in connection with Government work or investigations including aggregates of all kinds, building stones, alkali

soils and waters, powders of various kinds for mechanical analysis,

waterproofing compounds, drain tile, stucco materials, bricks, and

concrete products.

The service of the San Francisco branch laboratory is worthy of

particular mention in that aside from its cement inspection it handled

311 samples of miscellaneous materials. A great deal of work was

done on bituminous coatings for concrete ships, and analyses were made of paints, oil, varnishes, clays, lubricants, metals, waterproofing

compounds, and engine cylinder deposits. Departments and bureaus

served by this branch included the Navy, Post Office, Shipping

Board, Public Roads, Forest Service, Army Air Service, Lighthouses,

and Reclamation.

Aside from cement inspection service the work of the Denver

laboratory has consisted mainly in tests and investigations of concrete, concrete aggregates, and structural materials, largely for the

Reclamation Service.

Testing of Cement for Government Purposes.

Shipments of certified cement for Government projects showed a marked decrease over the preceding year. However, with the completion or suspension of many war-time enterprises, it was noticeable

that there was an increase in the demands from work of a more nor- mal nature—dams and river development, irrigation, bridges, and

District of Columbia work. Total shipments Avere approximately

1,200,000 barrels. Their monthly distribution is shown in the following table, which also affords comparison with the years 1916-17 and

1918-19. The former represents work before the unusually large

demands of war activity, and the latter was the busiest year of the

service. It is believed that shipments during the recent months

would have been much larger had there not been such serious car shortage. If Panama Canal shipments are excluded from the totals,

the increase of the past year over prewar requirements is marked.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 205

Month.

Shipments of tested cement in

barrels.

1916-17 1918-19 1919-20

Ipjjf. 36, 568

14,941

5S, 765 32,150

27, 388

16 012

29,' 063 43,744

54,525

48,718

64,325

76,646

1,121,960

1,053,167

1,053,998

948, 937

719,711

247 137

186' 806

182, 265 311,210

280,229

255, 646

227, 857

144, 421

168, 141

138, 164

133, 462 118,648

79, 894

66, 285

70, 835 79,590

53,798 56,605

August . September

October.. . November.. December

January

February March . April May... June :

J Total 502,845 6,588,923 1,190,782 Excluding Panama Canal 207, 125 72,000

6,40i,923

742, 000

1,044,032 Rejections 125, 919

Inspection was made at 64 mills in the following 19 States : California, Colorado, Georgia, Illinois, Indiana, Kentucky, Maryland,

Missouri, Montana, New Jersey, New York, Ohio, Pennsylvania,

Tennessee, Texas, Utah, Virginia, West Virginia, and Washington.

Naturally the cost per barrel of this inspection was not as low

as in the preceding year. This was due partly to the fact that

•changes in the inspection force could not keep pace with decreasing

shipments, partly to the fact that unit costs are necessarily somewhat

higher with a smaller volume of work. On the other hand the value

of the work is not indicated alone by costs per barrel. The amount

of cooperation and investigational work contributed in connection

with the service is considerable, and not infrequently retests and

special tests are made for the information of the purchasing department.

It is again to be earnestly recommended that the- inspection and

testing of cement be provided for by adequate appropriations.

Estimates obtained from the Government departments during the

latter part of the year indicate that approximately 2,000,000 barrels

of cement will be required during the year ending June 30, 1921.

All the funds available for both testing and investigational work in

cement will not provide for this amount of inspection, and in the

endeavor to provide for as much of this work as possible the con- tinuing investigations will have to be in part set aside entirely and

in part seriously curtailed.

Changes in the Branch Laboratories.

As planned in the preceding year, the San Diego branch laboratory was closed July 31, 1919, and the territory which it served was taken

over by the San Francisco branch. Additional funds provided

by the deficiency act and made available in November, 1919, enabled

the San Francisco and Denver laboratories to be supplied with

greatly needed equipment. Universal testing machines of 100,000

pounds capacity were installed at both points, together with improved equipment for testing concrete and concrete materials. Additional space was provided by the Treasury Department for the

enlarged facilities at San Francisco.
206 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Conference on Cement Specifications.

An important conference was held at the Bureau on May 10, 1920,

between representatives of the American Society for Testing Materials and the Government departmental cement committee. Ever

since the organization of the Joint Conference on Uniform Methods

of Tests and Standard Specifications for Cement in 1912 the fine- ness requirement has been in dispute. The joint conference was

unable to come to a final agreement on this matter, and consequently on January 1, 1917, the present specification was adopted, but with a reservation on the part of the Government committee that a higher

fineness requirement would go into effect the following year. In the war emergency this requirement was deferred, but the Government

committee eventually decided that the increase should be effective

January 1, 1921. At the conference of May 10, however, an agree- ment was reached whereby the fineness requirement in the specification should be a maximum residue of 22 per cent on the No. 200

sieve, without tolerance in the fineness determination, effective January 1, 1921. This agreement therefore stands as the final achievement of many years' work on the part of Government engineers and

representatives of the engineering societies to bring about uniform

specifications for Portland Cement throughout the country.

Foreign Cement Specifications.

The war interrupted the collation of foreign Portland cement

specifications. This work has now been resumed, and an effort is being made to obtain the latest specifications. Already many replies

have been received from the consular agents in the various countries.

Publications Relating to Cement and Concrete.

The publications by the staff of the cement section include the fol- lowing, which have appeared during the year

:

Structural Laboratory Investigations in Reinforced Concrete Made by Concrete Ship Section, Emergency Fleet Corporation. (W. A. Slater.) Proceedings American Concrete Institute. Volume XV, page 24, 1919. Tests of Concrete Tanks for Oil Storage. (J. C. Pearson and G. A. Smith.)

Proceedings American Concrete Institute. Volume XV, page 186, 1919. Cements Producing Quick Hardening Concrete. (P. H. Bates.) Proceedings

American Society for Testing Materials. Volume XV, page 425, 1919. New Developments in Surface Treated Concrete and Stucco. (J. C. Pearson and J. J. Earley. ) Proceedings American Concrete Institute, Volume XVI,

page 70, 1920. Compressive Strength of Concrete in Flexure. (W. A. Slater and R. R.

Zipprodt.) Proceedings American Concrete Institute, Volume XVI, page 120. 1920. Tests of Plain and Reinforced Gypsum Beams. (W. A. Slater and G. P. Anthes.) Journel Western Society of Engineers, September. 1919. Specifications for the United States Standard Sieve Series. (J. C. Pearson.)

Proceedings American Concrete Institute, Volume XVI. page 70, 1920. Reprints

of this paper are available for distribution to those interested, and copies may

be obtained, until the supply is exhausted, on application to the Bureau.

Tests of Two Recent Theories for Proportioning Concrete. (G. M. Williams

and Watson Davis.) Engineering News-Record, June 12, 1939. Subsequent

discussions and contributions on this subject were published in Engineering

News-Record, August 14. 1919, and April 22, 1920; Canadian Engineer, January

1 and 15, 1920. How Can Laboratory Tests of Concrete Materials Be Made of Greater Value

to the Field Engineer and Contractor. (G. M. Williams.) Engineering and

Contracting, February 25, 1920 ; Concrete, April, 1920 ; Canadian Engineer.

January 29. 1920.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 207

Flowability of Concrete and Its Measurement by Means of the Flow Table.

(G. M. AVilliams.) Engineering News-Record, May 27, 1920; Concrete, June, 1920 ; Engineering and Contracting, June 2, 1920 ; Canadian Engineer, June 10, 1920; Concrete Products, June, 1920. The following are in course of preparation or in press : Tests of Bond Resistance Between Concrete and Steel. (W. A. Slater, F. E.

Richart, and G. G. Scofield.) Pouring and Pressure Tests of Concrete. (W. A. Slater and A. T. Goldbeck.)

The Effect of Repeated Reversals of Stress on Double-Reinforced Concrete Beams. (W. A. Slater, G. A. Smith, and H. P. Mueller.)

An Investigation of the Causes of Cracking in a Concrete Barge. (W. A.

Slater and G. G. Scofield.) Test of a Concrete and Hollow Tile Floor Reinforced in Two Directions. (W. A. Slater, A. Hagner, and G. P. Anthes.)

Some Determinations of the Stress Deformation Relations for Concretes Under Repeated and Continuous Loadings. (G. M. Williams.)

LEATHER.

This work is concerned with the investigation and testing of

leather and leather goods to determine the plrysical and chemical

properties and relative durability of different kinds of leather upon

which to base standards of quality.

Sole Leather.

Service tests to determine the comparative durability of chrome

tanned and oak tanned sole leather have been completed. The chrome

leather used was heavily filled with greases and was of the same type

as is furnished to the shoe trade. The oak leather was tanned by the

long-time process with vegetable tanning materials and represented

a high quality commercial leather. Eesults of 28 tests showed that

the chrome leather outwore the oak by approximately 23 per cent per unit thickness.

The following tests are nearing completion and the results will be

available within a short time : 1. Comparative durability of hemlock leather filled with glucose

and salts, and hemlock leather to which these materials were not

added.

2. Comparative durability of hemlock leather filled with glucose

and salts, and oak sole leathers to which only a small amount of glucose and salts had been added.

3. Comparative durability of hemlock leather not filled with

glucose and salts, and oak sole leather to which only a small amount

of glucose and salts had been added.

4. Comparative durability of waterproofed and nonwaterproofed

oak sole leather.

5. Comparative durability of light and heavy rolled oak sole leather. An investigation is in progress to determine the durability of

leather tanned and filled with vegetable tanning material, as compared with leather tanned with vegetable materials and filled with

sulphite cellulose extract. Five hides were prepared by each of three tanners for this work. One side of each hide was prepared with the

vegetable tanning materials, while the other side of each hide was

prepared by using sulphite cellulose extract for filling.

Leather is being prepared to determine the comparative wear of

chrome and oak-tanned leather made from the same hide.
208 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Harness Leather. Tests have been completed showing the effects of the amount of

stuffing content and the degree of tannage on the physical properties

of russet harness leather. The results also show the variation over

the hide of the tensile strength per inch of width and per square inch,

buckle strength, percentage elongation, thickness, and the stuffing content. Upper Leather.

Animal and Fish.—A study is being made of the merits of shark

and porpoise leathers as compared with calf and side leathers for use in shoe uppers. The laboratory work will consist of comparative strength, elongation, tearing, moisture penetration, and microscopic tests of the two kinds of leathers. Several shoe manufacturers are cooperating with the Bureau to the extent of furnishing shoes with which actual service tests will

be made to compare the durability of these two leathers. One shoe

of each pair will have a fish leather upper and the other shoe will nave the calf or side leather upper.

Effects of Disinfectant.—Tests were made to determine the effects of disinfectants used by the War Department upon the upper leather

and linings of Army shoes. Physical tests made on the treated and

untreated materials showed no deterioration.

Organ and Piano Leathers.

In cooperation with the Bureau of Fisheries an investigation of

leathers used in the manufacture of organs and player pianos has been

undertaken with a view to ascertaining the suitability of animal and

fish intestines for this purpose. A preliminary report has been issued

describing the uses of the leather and the kinds of leather employed

by numerous manufacturers. Difficulty is experienced at present

chiefly with the sheep and lamb skin slavers used for diaphragms

in the action.

Information thus far obtained shows that there is in general no

leather which has been adopted as standard by all manufacturers for

any particular purpose. An effort will be made to develop such

standardization.

Microscopic.

An investigation of the structure of tanned leather is being made

by the use of photomicrographs in order to provide means of identifying the various tanned skins.

Several methods of preparing leather specimens for microscopical

examination have been studied and photomicrographs of various

leathers have been prepared showing the fiber bundles, cross sec- tions, and both the grain and flesh surfaces.

Special Tests. Standard Army Shoes.—An investigation was made at the request

of- the War Department of the sutability of a proposed Army shoe

for adoption as standard for all purposes. A favorable report was made by the Bureau as a result of service tests conducted at Camp

Sherman and the shoes have been adopted as standard by the United

States Army.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 209

Visor Edgings.—A comparative test was made of sheepskin skivers

and artificial leather for use as visor edgings on United States Army

officers' caps. The artificial leather showed a greater strength than

the real leather on account of the fabric backing. However, an in- spection of the two materials in service showed that the coating of the

artificial leather cracked and peeled off after a short time, and that

the real leather remained in good condition. It was recommended

that artificial leather be not used for this purpose.

Shoe Soles. At the request of a manufacturers' association, a study was made of

the merits of a special type of composition sole which had a veneered

wood backing, as compared with leather. As a result of the Bureau's

investigation, including actual service, pliability, flexibility, and conductivity tests, certain changes have been made in the details of design

and further tests are now being made to determine the value of the new type of construction.

Routine Tests. As usual a part of the time during the year was devoted to routine

work in the way of physical tests and chemical analyses for the vari- ous Government departments and for manufacturers. The materials

tested included sole leather, harness leather, strap leather, bridle

leather, leather belting, fish leather, rawhide, calfskins, lace leather,

baseball covers, welting leather, and artificial leather.

Specifications.

Specifications for black and russet strap leather were developed for

the Panama Canal, and a specification for leather to be used in brief

cases was developed for the General Supply Committee.

Publications.

The following publications were issued during the year

:

Technologic- Paper Xo. 13S, " The Effects of Glucose and Salts on the Wearing

Quality of Sole Leather." Technologic Paper Xo. 147, "An Apparatus for Measuring the Relative Wear

of Sole Leather and the Results Obtained with Leather From Different Parts

of a Hide."

Technologic Paper Xo. 153, "Area Measurement of Leather." Technologic Paper Xo. 160, " Effects of Oils, Greases, and Degree of Tannage

of the Physical Properties of Russet Harness Leather." Miscellaneous.

Artificial Leathers.—An investigation of the properties of artificial leather and the development of tests and testing apparatus are

in progress with the idea in view of securing a suitable specification

for this material. The Coated Textile Manufacturers' Association

is cooperating in this work.

Pyroxylin Plastics.—The Bureau was requested to investigate the

properties of pyroxylin plastics with the view of securing important

information.

Samples were submitted by three representative American manufacturers. The physical properties are being investigated under

different conditions of temperature and humidity. These data, to- 10613—20 14
210 REPORT OP DIRECTOR OP BUREAU OP STANDARDS.

gether with information regarding the electrical, chemical, hydroscopic, optical, and thermal properties, will be published.

RUBBER.

This work is made up of the investigation and testing of rubber

and rubber goods to determine their physical and chemical properties and to develop specifications, the manufacture of special rubber

articles for use in the Bureau's laboratories and the development of

methods of testing and design of new testing equipment.

Specifications for Automobile Tires and Inner Tubes.

All purchases by the War Department, Panama Canal, and other

Government offices of solid and pneumatic tires and inner tubes are made on the basis of tests and analyses conducted at the Bureau.

The Navy Department has likewise adopted specifications for pneumatic tires prepared in cooperation with the Bureau.

Power Loss in Tires.

Owing to an unavoidable delay in the delivery of dynamometer

equipment no progress was made in the investigation of power losses in tires. The apparatus which is now available will be used in a

series of tests to be made in cooperation with the Motor Transport

Corps and the Society of Automotive Engineers. A study will be

made of different types of tires and of tire fillers under definite conditions of speed, load on tire, and power transmitted. The results of this research will be of particular interest to tire manufacturers

in view of the necessity for reducing to a minimum the energy dis- sipated in tires, which often causes a rise of temperature sufficient to produce serious injury.

The International Standardization of Tire Sizes.

The Bureau has cooperated with the American Metric Association

in recommending and promoting an international standardization

of tire sizes. The importance of such standardization was brought

out very clearly during the war, when it was found necessary to change the wheels on some of our motor cars in order to permit the

use of tires manufactured abroad.

Hospital Rubber Supplies.

The Bureau was called upon during the war to conduct numerous

tests and analyses of hospital rubber supplies for the War Department. As a result of this work and at the request of the Field

Medical Supply Depot of the Army, specifications have been pre- pared for stoppers, tubing, hot-water bottles, ring cushions, sheet- ing, and surgeons' gloves.

Rubber Used in Connection with Airplane Equipment.

The Bureau has cooperated with the Air Service of the War Department in the development of specifications for leak-proof gasoline tanks and rubber shock absorbers, and in the production of a satisfactory rubberized silk fabric for diaphragms used in connection with autographic instruments. Diaphragms of thin and very
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 211

flexible rubber have been made for use in connection with specially

designed instruments.

Fire Hose.

Work of testing fire hose for Government departments has been

continued. For a number of years all hose used by the local fire department has been purchased on the basis of tests and analyses made

at the Bureau. The specifications formerly used are now being re- vised by the Bureau.

Miscellaneous Rubber Goods.

Under this heading are included a large variety of articles, such

as hose of various kinds, belting, valves, packings, rubber-covered

wire, shock absorbers for airplanes, jar rings, rubber bands, etc. A

total of 772 samples were tested during the year. Rubber Jar Rings for Canning.

The Bureau has continued its cooperation with the Department of

Agriculture in the testing of jar rings. A specification developed by

request of the States Belation Service has served a useful purpose,

having been published by the Department of Agriculture and recom- mended for use by the public. The simple and practical tests called for in this specification have proved to be an effective means whereby

the user may detect inferior quality in jar rings.

Rubber Analysis.

An important part of the Bureau's analytical work consists in the

determination of the amount of rubber and ingredients that are used

in rubber goods purchased by the various Government departments.

The long list of ingredients mixed with rubber is constantly being

enlarged. The properties of some of these ingredients are such that

the usual methods of analysis give incorrect results. Thus the exist- ing methods must be frequently added to or revised.

The use of glue, cellulose, and free carbon made it necessary to develop methods of analysis by which these ingredients could be

measured quantitatively. These problems have been completed after more than a year of experimental work. Papers on the detection

and determination of glue, and on the determination of cellulose and

free carbon have been published. A paper on the use of mixtures of

acetone and chloroform and of acetone and carbon bisulphide for

the extraction of rubber goods has also been published.

A large amount of antimony sulphide is used as a red pigment and

sulphur carrier in rubber goods. A satisfactory procedure for the

determination of antimony which has recently been worked out will

be prepared for publication in the near future.

The mineral fillers in vulcanized rubber are usually determined by

ignition. This involves the loss of some constituents and changes in

the composition of others. By use of a suitable organic solvent it is possible to remove the rubber and to leave behind all the mineral

matter practically unchanged in composition. For more than a year

this problem has been studied at intervals. One excellent solvent,

because of its slight action upon certain constituents, had to be dis- carded. However another solvent has been found which seems to be
212 REPORT OF DIRECTOR OF BUREAU OF STANDARDS

all that could be desired. Additional work will be done to determine

its value definitely before the method is given publicity.

The method for the determination of sulphur was so modified as to lessen the time required. Indeed, the Bureau's general analytical

procedure has been modified in many minor details so as to save time

without loss of accuracy.

Miscellaneous Materials.

The testing of miscellaneous materials has become largely a matter

of routine according to methods developed during the past 10 years

in testing Government supplies. As typical examples of such materials may be mentioned asbestos gaskets, canvas belting, linoleum,

flax shot lines used by the Coast Guard, window cord, hack saw

blades, shoe laces, etc. Special equipment has been developed for

testing some of these materials and in such cases similar tests are made for manufacturers upon request.

TEXTILES.

The activities of this section are quite varied and include the in- vestigation and testing of textiles to determine their physical, chemical, microscopic, and aesthetic properties, the development of new

materials, preparation of specifications, investigation of manufacturing processes, and aid in the establishment of a scientific basis for

textile testing.

Definition.

Textiles is rather a broad term and somewhat hard to define, but

in general it may be considered to refer to such manufactured articles as fabrics, hosiery, and knit goods, felt goods, cordage, twine, laces,

braids, and embroideries, which are made from a number of different raw materials, including cotton, wool, silk, flax, hemp, jute, etc. On

account of the great diversity in the uses to which these materials

themselves are put. the}' are somewhat difficult to classify. Unfortunately there is room for a great many misunderstandings under the

present unsatisfactory methods of classifying textiles and the materials from which they are made, and it is largely for this reason

that much of the work now under way at the Bureau has been taken

up. A close cooperation between the textile manufacturer, the sell- ing agencies, the public, and the Bureau is necessary in order to make

this investigation a success. It is believed that the Bureau's position as an unbiased third party is a strong one. and is becoming

recognized as such by both the makers and users of textiles. General Facilities. Owing to the improved facilities for research and test work, made

available through the removal of the textile section to its new quarters in the Industrial Building, the Bureau has been able to occupy

a more important position than ever before in relation to the textile

industries of the country. Its cooperation with manufacturers of

this class of goods will undoubtedly be greater than ever before.

The section may be considered as divided into seven groups for

routine and research problems, namely:

1. For cotton manufacturing problems.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 213

2. For wool manufacturing problems.

3. For felt manufacturing problems.

4. For the physical testing of textiles.

5. For the chemical testing of textiles.

G. For the microscopical and photomicrographical analysis of textile materials.

7. For the compilation of statistics and reference data.

In almost every textile problem presented to the Bureau for solu- tion all the above facilities are employed to a greater or lesser extent.

It is hoped that during the coming fiscal year progress along all the

above lines will be sufficient to warrant issuing a series of publications dealing with textile testing.

Microscopy of Textiles.

Microscopic and photomicrographic methods are becoming of

greater importance and are being more generally employed in the

study of various problems arising in the manufacture and analysis

mi textile fabrics. This section has been able to make a more

thorough study and analysis of the properties of balloon and air- plane fabrics by means of photomicrographs of these materials than

could otherwise haA~e been done.

In the study of textile fibers and the analysis of fabrics for fiber composition the microscope is indispensable, and is becoming

generally so regarded. In order to promote the intelligent and sys- tematic use of the microscope in this field this section is preparing

[a series of photomicrographs of textile fibers which are intended

|to show as clearly and distinctly as possible their physical characteristics, such as relative lengths and diameters, markings, thick- ness and regularity of walls, shape of ends, etc. For this purpose, of course, the individual, and not a bundle of fibers, is used.

It is also thought that considerable information regarding the

standard grades of some of the fibers, such as wool, may be disseminated in this way.

Plans have been made for this work and a few of the photomicrographs have already been made. It is the intention of the

Bureau to have this work completed by the end of the fiscal year

1920-21.

Nomenclature and Definitions of Textiles.

An outline has been prepared for extensive work leading to the

standardization of the nomenclature of textiles and definitions of

yarns and fabrics, pointing out the different characteristics and

limits of acceptability. The great need of this work is demonstrated by the lack of information, which may be secured by the

purchaser of even staple fabrics concerning differences between vari- ous kinds of material.

For specialized fabrics, the practice of various manufacturers of

substituting materials and names has caused considerable confusion,

and textiles that have practically nothing in common are very often

sold under the same name. The work can not be handled wholly

by the Bureau, but will call for the assistance of the manufacturers,

the converter, selling agents of textiles, and the retailer, as well as

associations interested in the study of home economics. A circular

will be published, Avhich will be enlarged periodically, dealing with

this much needed work.
214 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Problems of Wool Manufacturing.

At the request of the president of the National Association of

Wool Manufacturers a conference was held at this Bureau to discuss

the possibility of conducting a number of industrial research problems on wool manufacturing and performance of the various wool

fibers, yarns, and fabrics. One of the most important problems submitted was that of the standardization of dyestuffs from a chemical

point of view, going a step further than the work now being carried on at the Bureau of Chemistry, Department of Agriculture, with

specific reference to the existing cooperation of this Bureau on color

standardization as confined to colorimetry. It is possible in this

Avay to classify dyestuffs which are capable of a definite performance and which are now sold under a multitude of names, varying

with the manufacturers.

Through laboratory and service tests, which will aid in the solu- tion of problems relating to manufacturing methods and the substances used, interesting results will be secured which it is hoped

will point out the superior methods and ingredients.

Another very important problem submitted was the question of

the effect on the warmth and wearing qualities of garments, of the

introduction of blends of shoddy of different grades and also of

cotton with virgin wool. Results already obtained from abrasion

tests and measurements of tensile properties can be utilized to good

advantage in these problems. Although the work has been only

outlined in this year's report, actual progress and possibly the completion will be accomplished in the present fiscal year. Aircraft Fabrics.

Both the training and operations group of the Balloon and Airship

Division, War Department, and the Bureau of Construction and

Repair, Navy Department, have decided to continue part of their

large program of research on aircraft fabrics as originally outlined.

The textile section has therefore extended its cooperation in a further

endeavor to solve some very important problems. This work was

started some few years ago, but has never been completed, although

many things have been accomplished and important facts ascertained.

With the new equipment, which was originally procured for this

purpose, already installed, experiments will be greatly expedited. In

the new experimental cotton mill it is possible to make airplane and

balloon fabrics of various constructions and characteristics, depending

on the required performance. These can be given the prescribed

physical tests in our new constant temperature and humidity room.

Balloon Fabrics.

The balloon fabric committee of the Bureau of Standards, organized in 1917 to cooperate with the Army and Navy Air Services, has

drawn up a schedule of proposed research on balloon fabrics, which

has been followed in modified form during the succeeding years. The particular problem undertaken this year was the effect on the

permeability of a variation in the thread count and the finish of the

cloth used in making the fabrics.

Experimental cloths with a lower thread count than is at present

required were made by the Pierce Manufacturing Co. and rubberized
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 215

by the Goodyear Tire & Rubber Co. under the direction of this

Bureau, the Navy Department furnishing the necessary funds.

The weathering tests are not as 3*et complete, but from the data now

on hand it is thought that further work along the same general lines

will be recommended, as a successful solution of the problem will

insure a fabric which can be produced in large quantities and at a much lower cost than the fabrics now in use. World Cotton Conference.

A representative of the section attended the World Cotton Conference held in New Orleans and a meeting of the committee on re- search reports and statistics. The committee has been directed to consider and report upon a possible international system of reports

and statistics covering all phases of the growing, marketing, and manufacture of cotton, as well as the need for and possibility of re- search work in the textile industries. It also recommends cooperative research in methods of testing fibers, yarns, and fabrics with

the object of securing, as far as possible, standard international

methods, and urges a uniform system of expressing results. In ac- cordance with the above program this section is planning to be of

the greatest possible assistance in the work outlined and to act as a

clearing house for all information on possible solutions of research

problems concerning the manufacture of fabrics and commodities.

Waste-Silk Fabrics.

In order to assist the Salvage Board of the Ordnance Department

in disposing of a large quantity of spun waste silk, this section manufactured a small yardage of fabrics of special construction, having a spun waste-silk warp and a woolen filling. The fabrics were finished

for show samples having a width of 28 inches. Complete anaylsis

and testing brought forth indications of a superior fabric in regard to appearance, feel, and wearing qualities for the weight per square

yard. This was the first investigation of this nature carried on in

the new laboratories, and serves to illustrate the probable future use- fulness of the installation.

Abrasion of Suitings.

Following the successful building of an apparatus for abrading

textiles, a request from a private investigator to determine the re- sistance to abrasion of several samples of suiting, treated with a so- lution added to increase wearing qualities, was accepted. Requests

of this nature serve to indicate the trend of thought in the textile in- dustry along the lines of more complete and better knowledge of

the uses and performances of textile materials. Two widely different

types of fabrics were submitted to study the variation of the penetration of the solution into the interstices, and to determine the

effect of the solution as a fiber coating for increasing the wear re- sisting properties.

The results expressed in per cent decrease in tensile strength showed

that the solution did increase the strength of the untreated fabric,

and the cause of this can be logically traced to the fact that the solution increases the bond between the fibers, thus increasing the fabric

and yarn assistance. However, this does not necessarily prove or warrant a statement to the effect that the life was materially in-
216 REPORT OF DIRECTOR OE BUREAU OF STANDARDS.

creased, because of the wide deviations in results of tests on the

treated fabrics.

The abrasion machine itself is not a finished product, and work on new designs, together with chemical research on the subject, is now

underway. Eesults show the need of more detailed measurements,

and as soon as apparatus giving conclusive results is designed it will

demand immediate consideration from the manufacturer and con- sumer. German Substitutes for Burlap, etc. In accordance with a request from the Kesearch and Statistics

Division of the War Department, an extensive investigation was car- ried on to determine the probable performance, suitability, availability of material, etc., of samples of German fabrics used as substi- tutes during the war. A complete analysis of the fiber contents was made to show that no new fibers and compositions were used, cotton and coniferous fibers (as used in paper making) being the principal

contents. The results of the physical tests showed that the utilization

of short and inferior fibers for a superior purpose was not practicable

for the weight and volume of material allowable for a specific use. The ingredients used as waterproofing and disinfecting agents were

determined by chemical analysis. It is noted that the substitutes with

cotton fibers contained approximately 40 per cent of sizing com- pounds of different characteristics and were presumably added for

certain definite uses. The analyses serve to indicate the great need of like attempts to develop substitutes, and point to the importance of paying particular attention to a study of the desired performance of a manufactured and finished commodity rather than an investigation of the raw material.

Manufacture of Denims at Atlanta Prison.

Through the efforts of the executive secretary of the National

Committee on Prisons and Prison Labor, an extensive investigation was undertaken by this Bureau on which to base recommendations

as to the best type and weight of denims to be manufactured, together

with the necessary steps to change the mill at Atlanta for such manufacture. This mill is now making a large amount of ducks. It was de- cided to first obtain as large a number of samples of denims as possible

from the various State and Federal institutions and prisons, together

with information as to the kinds used, methods of purchasing, and

a statement of the probable wear in terms of months; then to per- form the necessary physical and chemical analyses which would

result in tentative specifications of denims. The results of this work

proved very satisfactory and helpful. Similar work using the above

method of procedure has been started on materials such as sheeting

and ducks. This cooperation can be taken as an example of what

can be accomplished by the Bureau on receipt of requests of this

nature from priArate concerns as well as Government organizations.

Specifications.

It has been found that several of the Government departments are buying the same general types of material, but under slightly different

specifications. The slight variations from commercial fabrics are
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 217

often just sufficient to make necessary the manufacture of special

fabrics for the Government. This, of course, limits the supply and

increases the cost to the Government very materially.

In the past year, acting on the advice of the Bureau, some of the

departments have eliminated these conflicting specifications and have

adopted specifications for commercial cloths in their place. It is thought that this procedure should be followed, as there are very few

instances where the requirements of the fabric under working conditions can not be successfully met by commercial fabrics.

A general form has been used in Avriting specifications in order to

secure, in so far as is possible, a uniformity of Government specifications. In many cases it was found that the existing specification

had been created without a thorough knowledge of what the characteristics of the fabric should be, and to prevent a failure occurring

a much better fabric than was necessary was specified.

The Bureau has been following the policy of inviting the manufacturers to criticize all specifications before they are recommended

to the department for use in purchasing supplies.

Cotton Fire Hose.—An investigation was made to determine what

constitutes desirable properties in fire hose, and in cooperation with

the rubber section specifications covering the manufacture and in- spection of cotton fire hose embod}'ing these characteristics have been

written. These specifications will be published as a Bureau circular.

Plumbers' Oakum.—During the past several years the Panama

Canal authorities have had difficulty in purchasing a plumbers'

oakum which would successfully meet their requirements. The sec- tion was asked to furnish specifications which would insure the

furnishing of the desired oakum. After an investigation, which in- cluded the analyzing of samples from the principal manufacturers

of this material, specifications Avere fuimished governing the manufacture and inspection of plumbers' oakum.

Meritas Composite Cloth.-—Meritas composite cloth is used for the

tops and sides of the covered Army trucks and is made by cementing

two plies of cloth together with a flexible adhesive oil and water- proofing compound containing no rubber. At the request of the

Motor Transport Corps the existing specifications were thoroughly

investigated and several changes were recommended to insure a more

uniform and better wearing fabric.

Cotton Bunting.—Acting on the advice of this section the Panama

Canal authorities decided to purchase cotton bunting in place of

wool bunting for use in the Canal Zone. Complete specifications

governing the manufacture and inspection of cotton bunting were

furnished by this section. It is estimated that the use of cotton bunting will save the Panama

Canal about 50 per cent of their annual expenditures for wool bunting and at the same time give an equally serviceable bunting.

Rubber Sheetings and Mechanical Rubber Goods.—At the request

of the commanding officer of the field meclical-supply depot and in

cooperation with the rubber section of the Bureau specifications were

prepared governing the manufacture and inspection of rubber sheet- ing for hospital use and for the cloth entering into the manufacture

of mechanical rubber goods, such as air cushions, hot-water bottles, etc.
218 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Work for Tariff Commission.

Over 100 samples of imported fabrics were submitted for complete

analysis and physical testing by the Tariff Commission. In addition

to these requirements one or more photographs were made of each

fabric to show the yarn and fiber characteristics, the construction,

and the design with color schemes. These data not only supplied

information upon which rates may be based, but form a permanent

record of each type and design of fabric submitted. The work has

not been completed, but it is expected that it will be finished in about

a month.

Flameproofing of Parachute Silk. A number of specific tests were made on parachute silk treated

with a solution of sodium tungstate to determine the extent of its fire resisting properties. At the request of the Director of the Air

Service of the Army samples were made up and treated, and then

observed on the application of flame. Eesults showed that inasmuch

as the silk is composed of organic matter its destruction can not,

of course, be prevented when any part of it comes in contact with

a flame or a sufficiently hot substance; that the impregnation of

sodium, tungstate solution can serve to prevent the spreading of

fire over the material when a flame comes in contact with any part

of it ; that the solution is removed by washing in water or when subjected to a heavy rain, thus necessitating the application of more

of the solution if the material is to remain fire resistant; that a

slight change in the physical properties was noted to the extent of

6 to 10 per cent loss in tensile strength and an increase in stretch

of 10 to 20 per cent upon the application of the fire-resisting solution.

Further tests would give additional information, such as the effect of exposure to sunlight, storage, and use upon the impregnation of

the silk. Test Specimens for Tensile Strength of Ducks.

At the request of a commercial laboratory for the testing of textiles, a series of experiments were completed to show the relation

of the single yarn breakage to the breakage of the fabric by the

" strip " method of test, as recommended by the Bureau, and dif- fering from the so-called " grab " method of testing the tensile

strength of fabrics. The results pointed out more clearly the conclusions given in a publication previously issued by this section and

entitled " The Strip Method versus the Grab Method in the Determination of the Tensile Strength of a Fabric."

Spanish Moss as a Mattress Filler. A determination was made by physical tests of the suitability of

" Florida " or " Spanish " moss as a substitute for other fibrous materials as a matress filler. The problem was submitted by the Division

of Research and Statistics of the War Department. Careful con- sideration was given the subject and a comprehensive report was

sent out giving the problem a tentative program, the results of which

will be of great interest. Final conclusions were withheld because

the test specimens were too small to give definite information as to the performance of the filler in a full sized mattress. Some of the
REPORT OF DIRECTOR OE BUREAU OF STANDARDS. 219

properties investigated were ease of manufacture, elasticity, resili- ency, rate of absorption of energy, density, and tendency to cohesion of the individual fibers. Investigation of Materials for Sandbags.

In cooperation with the paper section of the Bureau, a study of

the requirements of sandbags as used in trench and barricade warfare was outlined, with special reference to the cost, availability,

methods of manufacture, and durability when being transported and

handled under all conditions of weather and location for a period of

predetermined life. This work was undertaken at the request of

the War Department, and this department is conducting the actual

service tests. A description of the test methods can be found in the

report of the paper section.

Sail-Canvas Investigation.

A short investigation was conducted at the request of the New

York Yacht Club on specimens of canvases to be used as sail cloth

for the American cup defender Resolute. A comparison was made

of the cloth made for the defenders sails in 1914 with the cloth used

in this year's sails. The results showed that one fabric had a slight

increase in tensile strength, due to a longer-staple cotton and a slight

change in the cloth construction. No appreciable loss in strength

due to storage was noted in the 1914 fabric, showing that the method

of storage was carefully considered by the club. Stress-strain rela- tions indicated that the performance of both fabrics would be about

the same. Shade Cloth.

The contemplated purchase of shade cloth for the windows of the new industrial building of the Bureau warranted a request to this

section for complete tests on specimens of the material submitted.

Special attention was given to their fastness to light and also to the

brittleness and elasticity of the filler whenever present. It was

concluded that the resistance of the material to cracking should be

considered as the quality next in importance to light fastness. Consideration was given to the construction of the fabric, fiber contents,

amount of filler necessary to prevent the translucency of the shade,

and period of serviceability. Investigations of this nature should aid

the public in obtaining a more serviceable commodity. Plans have

been made for continuing the work through the coming year. Fish-Net Investigation.

A tentative program has been drawn up for an investigation of

ingredients used to prolong the life of fish nets as used in the Great

Lakes and other fresh waters of this country. The cooperation of the

Bureau of Fisheries and an interested manufacturer of fish nets has

been obtained. The results so far indicate that fish nets deteriorate

very rapidly in fresh water. The causes appear to be bacteriological

growth and repeated wetting and drying in usage. Sizing Compounds.

Preliminary work has been started on the investigation of sizing

materials for cotton yarns, and analyses have been made of these
220 REPORT OF DIRECTOR OP BUREAU OP STANDARDS.

compounds to determine their general applicability. In the process numerous samples of sized fabrics were examined for per cent of

size and nature of ingredient used. Some of the fabrics were submitted as routine work, but the analysis was carried further for in- vestigational purposes.

Cotton and Woolen Goods.

A large number of cotton as well as woolen fabrics were tested for

percentage of fiber content, fastness of color, nature of dye, paying

particular attention to the use to which the fabrics were to be put.

Results were used in drawing up tentative specifications, which for

the most part were requested by various Government departments.

Heating Pads.

At the request of a manufacturer tests were conducted to determine

the shrinking effect of heat on heating pads. The investigation,

although by no means an extensive one, brought out many facts in- teresting and essential to this particular manufacturer concerning the

best materials to use to obtain the desired performance. These tests, however, were not representative enough to warrant any general

recommendations concerning the manufacture of heating pads.

Routine Testing.

Over 3,300 samples were tested during the past year, principally

from Government departments, of which the Panama Canal, War

Department, Navy Department, and Post Office Department were

the chief contributors. The tests covered the whole field of textiles,

including fibers, yarns, and an unusual variety of fabrics as well as made-up materials, such as blankets, handkerchiefs, table linens,

hosiery, etc. The analysis of 100 foreign fabrics imported from

Belgium, Holland, England, Switzerland, and France and submitted

by the Tariff Commission was of special interest. Considering the

number of samples which have been tested and the care and accu- racy necessary in their preparation, it is very evident that routine

testing occupies an important place in the work of this laboratory.

Total Routine Testing of Textiles.

Number of samples. Fees.

3,301

72

S7, 939. 50

298. 50

Total 3, 373 S, 238. 00 Estimate of routine testing in research problems 6, 975. 00 Grand total 15. 213. 00

PAPER.

This section is concerned with the development of methods of test- ing and with the preparation of specifications for paper of all kinds,

especially in connection with paper for certain definite uses. This

Avork is of benefit not only to the Government in the purchase of

supplies, but also to the public and paper manufacturers.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 221

Facilities. The paper testing laboratories and the experimental paper machine have been moved to new quarters in the Industrial Building

and the equipment and apparatus have been arranged in four groups

or divisions. These groups consist of plrysical testing instruments,

chemical apparatus, microscopical and photomicroscopical apparatus, and paper-making equipment. Due to the fact that relative

humidity and temperature affect the physical properties of paper, a large room has been equipped with a conditioning apparatus to maintain 65 per cent relative humidity and 70° temperature. The

physical tests on paper are made in this room under these standard

conditions. A complete chemical laboratory and weighing room has

been arranged for the necessary chemical tests on paper and these

are equipped both for routine testing, and with apparatus used in

research work.

Since fibrous material is the chief constituent of paper, it is neces- sary to study its physical characteristics by means of the microscope.

This quipment is necessary, not only for identification and estimation of fibers, but also for the study of the characteristics of the

fiber. The paper-making equipment has been somewhat rearranged

and additional machinery has been obtained, which will materially

assist in this branch of the work. The new equipment consists of

a 300-pound concrete beater with necessary motor and stuff chests, a larger screen, a sheet cutter, and a supercalendar. This experimental paper mill, when fully installed, will probably be the best in

the country for studying the factors which influence the quality of

paper.

Tearing Strength of Paper.

During the past year, the tearing quality of paper has received

considerable attention from industrial laboratories. This test is used in a rough way by the paper maker to determine the quality

of paper. In the hands of an experienced man, it is often possible,

by tearing the paper with the fingers, to get a very good idea of

the characteristics of the paper. Additional work has been done on this test during the past year but the data are not yet complete.

In developing a scientific method of reproducing to some extent the

tearing of paper by hand, it is necessary to study the initial, the

maximum, and the aA'erage tears, as these vary to some extent with

different grades of paper. An attempt has been made to determine

the relative accuracy of three testing machines available and also to develop a machine that will give data that may be interpreted to show the strain on the paper which tearing produces. Due to the

method of making paper, its strength is not the same in the direction

the paper runs on the paper machine as it is at right angles to this. In addition, when tearing some papers at right angles to the direction

in which the paper was made, there is a tendency for the tear to be uneven and for part of the fibers to strip off. This must be taken

into consideration, as it seriously affects the test. It appears from

the data already available, that the size of the test sample used in- fluences the test. It also seems true that not only is the strength of

the fibers actually being torn or separated indicated by the tearing

strength but also that of the fibers on either side of the tear to a

considerable distance.
222 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Paper for Lime and Cement Bags.

Additional work has been done on the study of paper for use as bags for lime and cement. This investigation was started some years

ago and was discontinued during the war. During the past year, emphasis was laid on the development of the stress-strain test and

the correlation of it with the drop test. The stress-strain test gives an indication of the resiliency of the paper under successive loads

which are a constant factor below that which would produce rupture.

Both the number of times the load may be applied before the sample

breaks and the percentage elongation or stretch is taken into consideration. It is thought that the correlation of this test with service

tests will greatly assist in the development of specifications of paper

for this purpose.

Substitute for Sand Bags.

At the request of the War Department, an investigation, in co- operation with the textile section of the Bureau, was undertaken to obtain or develop a substitute for jute burlap for use as sand bags for

military use. A material was desired that would be reasonable in

price, which would resist weather conditions for at least six months,

and which could be obtained in this country in large quantities in

time of war. A number of samples of burlap, cotton fabric, plain

paper, reinforced paper, and specially treated paper were obtained

and tests were made in the laboratorjr to determine their relative

value. From the data obtained, it was decided to eliminate all but

five samples which showed promise of being of value for such work.

These were a burlap, a cotton fabric, a cement bag paper, a paper

reinforced with cotton fabric, and a waterproof paper, all manufactured commercially and available in large quantities. Bags of

the proper size were bought made of these materials and tests were made with them filled with sand. These included the drop test and the jolting test. The latter one gave an indication of the weakness of the glueing or of the sewing of the bag. Samples of the

materials were exposed to weather conditions on frames and were

also buried in the ground. Both of these sets of samples were tested

in the laboratory at stated intervals to determine their deterioration.

The data so far obtained seem to indicate that a heavy paper made

of old rope will be suitable as a substitute for jute burlap for sand

bags. It is desirable, however, that this paper be made more water

resisting and it is expected to make a study of the development of

this quality.

Sizing Quality of Paper.

There are a large number of factors that influence the sizing

quality of paper and, before going very far into this investigation,

it was thought necessary to develop a method of determining this

sizing quality. For some years the so-called conductivity method

of determining this quality has been used to some extent for mill

control work. As indicated in a previous report, it was thought

advisable to make certain changes in the apparatus. During the past

year, new equipment has been obtained and set up. It is now possible to determine the rate of penetration of an electrolyte through

a sheet of paper and to obtain a curve which represents this changing rate. It is proposed to study the factors in the sheet of paper
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 223

which may affect this test and to correlate the data obtained with

other tests of a more or less empirical nature. When this test is properly interpreted, it is planned to investigate the factors in the

manufacture of the paper which may influence the sizing quality

of paper.

Samples for Microscopic Estimation of Fiber Content.

It was found desirable to produce a new set of standard samples

of paper to be used for the microscopic estimation of the fiber content of paper. Sixty-seven combinations of fibers were made up into

3-inch disks, in the proportions usually found in commercial papers.

Due to the fact that commercial papers are beaten differently in different mills, it was not possible to reproduce this beating effect in

the standard samples. The fibers were all sufficiently beaten to felt into a sheet of paper, but their characteristics were retained. The

fibers used were rag pulp, coniferous and broad-leaf chemical wood

pulp, ground wood pulp, and manila and jute pulps. Several sets of these samples have been sent to paper mill laboratories for comparison and criticisms.

Sulphate Pulp Identification.

During the last 50 years the manufacture of sulphate wood pulp,

sometimes called " Kraft " pulp, has increased to such an extent

that it is used to a very large degree in papers requiring considerable

strength but where color is not important, such as wrapping and bag

papers. When examined under the microscope, using the customary

stain, it is difficult if not impossible to identify this pulp. The ex- tended use of this material has made it desirable to develop methods,

both for identifying it and for estimating the quantity of the material present. With this in mind, various stains and dyes have been

tried in order to obtain one that will react selectively with sulphate

pulp and other pulps with which it may be found. This work is nearing completion and a vast number of samples containing known

and unknown amounts of sulphate pulp have been examined. The re- sults of this work will be published in the near future and will be of

great value to all laboratories and mills that come in contact with

sulphate pulp.

Microphotographs of Fibers.

It has been possible to obtain a set of samples of authentic papermaking fibers, and microphotographs of these have been made. In

the development of the methods of taking these photographs great

improvement has been obtained and emphasis has been placed on

clearness of definition and absence of background. For this work,

additional apparatus has been obtained and developed, as it was

found desirable to have a very long camera bellows. It is now possible to extend the bellows to either 15 or 20 feet and this permits of

better definition and a flatter and larger field. The microphotographs produced are the equal of any appearing in print and are

A

Tery valuable as showing the characteristics of various paper-making

fibers. Microscopy of Paper-Making Fibers.

During the last two years a great deal of work has been done on

the methods and technic used in microscopy of paper fibers and the
224 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

proper use of the necessaiy instruments and apparatus. The routine

estimation of various fibers in the samples of paper has been standardized to a large extent and the investigational work has been put on a firmer basis. It is proposed to produce in the near future a publication giving the results of the work on microscopy of fibers Avith data as to the proper equipment and methods which will be of

value to industrial laboratories. The discussion of the methods will

include the value and use of various stains for bringing out the

characteristic markings of the fibers, and the pamphlet will be illus- trated with microphotographs of paper-making fibers. Paper from Unusual Fibers.

Due to the high price and scarcity of raw material for the manufacture of all grades of paper, especially newsprint and book papers,

there has been an increased interest in the utilization of straw, grasses, and other fibrous material for paper making. The demand for in- formation has become so great in certain cases that various fibrous

materials have been examined and in some instances manufactured

into paper. It is, however, to be regretted that in most cases those

interested in the use of these fibers have assumed that if a sheet of

paper can be produced in an experimental way, that the same thing can be clone commercially. This is quite often true in so far as the

actual manufacture is concerned, but seldom is it realized that the cost of the total operation is the chief limiting factor. Not only must

there be a large uniform supply of raw material, but it must be

within easy transportation distance; the cost of the preparation of

the fibers into pulp must be sufficiently low and the grade of paper

produced must haAre a market at a price that will alloAV some profit.

Many of the grasses and fibrous materials receiving attention at this

time have been investigated for a hundred years or more and very

few have ever been successfully used on a commercial scale. The

fibers examined during the past year are as giA-en beloAA-

:

Saw grass, spartina grass, Japanese cane, yucca plant, and flax straw

Avere made into paper in A^arious combinations, but these fibers were

submitted already cooked and were not further treated. Rice straw,

lalang grass, and banana stems from Siam were each made into paper

and were found to haAre some A^alue. The lalang grass gave a paper

somewhat similar to that obtained from esparto. JBagasse fiber, cot- ton stalks, and bleached munition linters have also been used for

manufacture into paper. But in practically all cases, as mentioned

above, it is not the actual manufacture into paper that is the great

difficulty. The collection of the material continuously in sufficiently

large quantities, the cost of cooking, the low yield, and the grade of

paper produced must be considered before planning to use these

fibers on an industrial scale. Mimeograph Paper.

The scarcity of paper and the difficulty of obtaining a sufficient supply for use in making mimeograph copies of data and information by this Bureau has led to the production of this grade of paper

Avith the paper-making equipment. Two results haAre followed from

this request for manufacture of mimeograph paper. In the first place, a paper Avas deA-eloped that was sufficiently " slack-sized " to permit of its use on the mimeograph machine and yet was ink-
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 225

resisting enough to permit its use when made up into pads for writing

purposes. In the second place, during the process of manufacture

considerable data are being obtained in regard to the factors influ- encing the quality of paper. These data will be properly collected

and tabulated and should be of value. The new beater which is being

installed will be especially helpful, as it was designed so that the

factors influencing beating could be studied at will. The product

of the mill in many of these experiments is used as mimeograph

paper.

Specifications for Lime for Cooking Rags.

At the request of the Interdepartmental Lime Conference, specifications were prepared governing the requirements for a good grade

of lime for cooking rags of the same grade for use in the manufacture

of paper. The presence of dirt and grit is very undesirable, and one

of the purposes of preparing rags for paper making is to eliminate

all the nonfibrous material. Cooperation was maintained with mill

laboratories, and the specifications were adopted by a technical committee of the paper industry. These specifications appear in full in Bureau of Standards Cii*cular Xo. 96. Routine Testing.

There are certain tests on paper which have been found available

and sufficiently accurate to .use in general work on most classes of

paper. These methods have become standardized and are used in

connection with most of the samples submitted for test. The equipment for such tests is always set up and is in constant use. To

facilitate the work this group of tests has been called routine testing,

and the routing of samples for such tests has been carefully worked

out. For much of the investigational work these routine tests are

necessary, and the term is of value mainly to distinguish standard

methods from proposed or preliminary ones. During the year a

total of L3G2 samples of paper were tested under this classification,

of which 3.090 were submitted by Government departments and 1.272 by public and private interests. Although routine testing is productive of but little fundamental

data, it is at the same time of considerable assistance in developing

specifications and in determining the accuracy of the instruments

used in paper testing and in judging the uniformity of paper of given

grades.

Miscellaneous Information.

During the past year a large amount of miscellaneous information in regard to the testing and manufacture of paper has been

given through correspondence and conversation with visitors. There

seems to be an increased interest in the testing of paper, and it has

been necessary to make many references to data appearing in trade

periodicals. For that reason it is planned to publish as soon as

possible a circular on paper, its specification and testing, giving

the common methods of procedure and the necessary equipment.

Information has been supplied to practically all the Government

departments in Washington that would assist them in the proper

purchase of paper. Some of these data were available, while in other

10613—20 15
226 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

cases special work had to be undertaken to obtain the desired in- formation. The paper-testing laboratories are always at the dis- posal of the Government departments, and an even greater cooperation would probably result in purchasing paper more consistent with

the needs of the Government and with the customs and practices of

the paper industries.

LUBRICATING OILS.

Standardization of Instruments.

A portion of this work includes an investigation of the Redwood

viscosimeter, in connection with other viscosimeter comparisons.

Mention of this research was made on page 113 of last year's report.

For various reasons the work has been delayed and, therefore, but

little progress can be reported.

A fuel oil viscosimeter, designed by George M. Saybolt, is at present

under investigation, and a MacMichael viscosimeter, which is an in- strument of the torsional type, has been thoroughly studied. The

results of this work were published in volume 12 of the Journal of

Industrial and Engineering Chemistry, for 1920, page 282. A less technical paper, prepared in collaboration with E. W. Dean of the

Bureau of Mines, will soon be published.

Viscosity of Oil Blends.

In connection with the work on viscosimeters, tables and diagrams were prepared for estimating the viscosities of oil blends. This

work is described in Bureau of Standards Technologic Paper No. 164

entitled " The Saybolt Viscosity of Blends " and a preliminary re- port on the same subject appeared in volume 22 of " Chemical and

Metallurgical Engineering " for 1920, page 1109.

Friction Machines.

The new oil friction machine, mention of which will be found on

page 113 of last year's report, is now in use, and two papers are in course of preparation which describe some results obtained with a

friction testing machine recently bought in the open market.

Routine Physical Tests. During the year physical tests were made on 1,193 samples of oils and greases. This very large increase in work, as compared with

previous years, was principally, if not entirely, due to the great number of samples received from the War Department. There was an

increase in spite of the comparatively few samples sent by the General

Supply Committee. Usually, all of the samples of lubricants submitted with bids are sent for test. This year the committee agreed

that only those samples for which demulsibility and carbonization

tests were required, should be tested. Chemical Investigations.

After many failures at intervals for several years, a satisfactory

method for the determination of sulphur in petroleum oils has been

devised. It gives results as good as those by the bomb calorimeter,

and can be used in laboratories where that apparatus is not available.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 227

A preliminary paper was published in the Journal of Industrial and

Engineering Chemistry, volume 12, page 482, 1920. The manuscript

of a more extended discussion of the subject was accepted for publication as a Bureau of Standards Technologic Paper.

Carbonization of Petroleum Oils.—This Bureau has already published four papers which have a bearing on what has come to be

known as the Waters carbonization test. This is often confused

with the Conradson carbon residue test. For this reason, and be- cause of many requests for information about the two tests, a circular

explaining the differences between the two is in course of

preparation.

Routine Chemical Testing.

There was a large increase in the number of samples received for

chemical examination. Most of these were also tested in the physical

laboratory. Among these may be mentioned numerous samples of

cutting oils received from the Public Health Service, which is making a special investigation of this subject.

Cooperative Work.

The chief of this section is the representative of the Bureau on

committee D-2, on petroleum products and lubricants, of the American Society for Testing Materials, and cooperation is likewise carried on with the committee on standardization of petroleum specifications.

LIME, GYPSUM, AND SAND-LIME BRICK.

The work of this section has to do with the development of

specifications for these materials, the improvement of manufacturing processes to produce better or cheaper materials, and the collec- tion and dissemination of knowledge which will lead to their more

efficient use. Popping of Lime Plaster.

Unless lime which is used for plastering purposes is properly made

and handled it is apt to pop. Small particles will hydrate after

the plaster is set. will expand, and push themselves out of the wall,

leaving small holes in the plaster. It is obviously essential that a

test for this tendency to pop, or unsoundness, be included in the

standard specifications for lime. Before such a test could be established as satisfactory it was deemed necessary to investigate the

causes of the phenomenon.

Accordingly, a research on this subject has been conducted by the

manufacture of plasters containing known amounts of suspected

ingredients. These plasters were exposed to the air for a year and

examined for signs of popping.

As a result, it may be stated that popping is caused by particles

of chemical compounds which are formed by the union of certain impurities with the lime in the kiln. These compounds can be distinguished from lime by their appearance, and can therefore be sorted

out. Small particles which escape the sorter can be taken care of

by soaking the lime paste overnight before using. If the particles are all fine enough to pass a No. 48 sieve, and there are not too many
228 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

of them, they may pop without leaving holes large enough to cause

disfiguration of the wall.

The final report on this subject has been released for publication

to the Journal of the American Ceramic Society.

Chemical Lime.

More than half of all the lime produced is sold as chemical lime;

that is, it is used as a reagent in the manufacture of other materials.

Hereto-fore it has been customary for each purchaser of chemical

lime to prepare his own specifications. This has led to great con- fusion in the industry. A certain quality of lime may be rejected

by one purchaser as failing to pass his specifications and accepted by

another purchaser using more lenient specifications, even though

both parties are buying the lime for exactly the same purpose.

The Bureau has invited representatives of various other Government bureaus to meet with it and to draft recommended specifications

for the various kinds of lime required by the chemical industries.

Before publication of these specifications, they will be approved

by the National Lime Association and by the corresponding national

association of the users. One specification has been issued—Recommended Specifications

for Lime for Cooking Rags in the Manufacture of Paper, Bureau of

Standards Circular No. 96. Three others are now in course of

preparation.

The Use of Hydrated Lime in Concrete.

Many contractors make a practice of adding small amounts of

hydrated lime to concrete. It has not yet been determined whether

or not this practice is justifiable. In 1915 the Bureau organized an advisory committee, composed of representative cement manufacturers, lime manufacturers, engineers, and contractors, to assist it in planning a research on this subject. During the past year a complete series of 4-year-old specimens were tested. Thus far the

committee has failed to agree on what constitutes a fair basis for

the comparison of concretes with and without lime, and the publication of test data is therefore postponed. It is felt that possibly

the criterion should be the working quality of the concrete. An in- vestigation to determine how this quality can be measured is now

under way.

Measurement of Plasticity.

Finishing hydrate, which is used for the third or white coat of plaster, sells for about $2 a ton more than other kinds of

hydrated lime. It differs from other kinds solely by reason of

its greater plasticity. Plasticity is therefore a property having

great economical importance, and a requirement for it must be

included in the specifications for finishing hydrate.

A method of measuring the plasticity of lime has been developed

by the Bureau. A description of the machine used is given in Technologic Paper No. 169. We are now collecting numerical data

so that fair limits may be established for the plasticity of finishing

hydrate.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 229

The Bond Between Mortar and Sand-Lime Brick.

Competitive salesmen, in attempting to prevent the use of sandlime brick, have stated that the brick does not bond Avell with mortar.

The Bureau was asked to investigate the truth of this statement, and

also to find out whether or not the bond could be improved by any

change in the character of the brick or of the mortar.

It was found that the bond between brick and mortar is surprisingly weak, and this statement is not confined to sand-lime brick.

The bond can be improved by careful *ontrol of the wetness of the

sand-lime mixture before it is pressed into bricks, and by properly

wetting the bricks before laying them.

During criticism of this report within the Bureau, the fact was

developed that, theoretically, the strength of the bond between brick

and mortar is of very minor importance in determining the strength

of the finished masonry. This theory was corroborated by further

experiment and, by recalculation of the data given in Technologic

Paper No. 111. The final report was presented at the 1920 meeting of the SandLime Brick Association, and will be published in their proceedings.

Time of Curing of Sand-Lime Brick.

Sand-lime bricks are made of sand and lime, mixed, pressed, and

cured with steam. The usual practice in the United States is to use steam at 100 to 150 pounds pressure for from 7 to 12 hours. Laboratory experiments indicated that a brick will attain nearly its full strength in four hours, and that the strength gained by longer

hardening is not sufficient to be economical. During the past year,

five manufacturers have cooperated by curing their bricks for differ- ent lengths of time and sending them to the Bureau for test. As a

result of this work, six hours has been established as the most economical time for curing the bricks. The adoption of 6 instead of the

present 7 to 12 hours will mean a considerable saving of both time

and fuel, without detriment to the quality of the product.

A report on this subject was read at the 1920 meeting of the SandLime Brick Association and will be found in their proceedings.

The Acoustics of Wall Plasters.

The question of acoustics, especially of public auditoriums and of

apartment houses, is becoming a very serious and important one. It

is generally conceded that much of the trouble caused by the reflec- tion and reverberation of sound is due to the design of the room, but

it is also suspected that the character of the walls may have something to do with it. To investigate this point, the Bureau has undertaken to measure

the quantity of sound transmitted, reflected, and absorbed, by all of

the usual types of wall construction. Twenty-one panels, each 4 feet square have been prepared. These represent all usual types of backing, such as different kinds of masonry and of lath ; different types

of plaster such as lime and gypsum ; different types of finish, such as smooth troweled and sand floated ; and different types of after treat- ment such as papering and painting. No tests of their acoustical

properties have yet been made.
230 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Colored Plaster.

From the viewpoint of both the architect and the owner, the usual

dead white color of a wall plaster is not satisfactory. Several at- tempts have been made to produce tinted plaster by the addition of some pigment to the plastering material. These have not been suc- cessful because it is almost impossible to match the tints of different

batches and the line of demarcation between work done at different

times is therefore glaringly pronounced, and also because plaster

colored in this way is still dead—the texture is displeasing.

The Bureau has produced an unlimited variety of colors and

textures by the use of gypsum wood-fiberecl plaster. The wood fiber

is dyed the desired color's before being mixed with the gypsum. By

scrubbing the surface of the plaster after it has set, these fibers can be made to stand out from the wall more or less distinctly, thereby

producing both color and texture. A report on this subject is now in course of preparation.

Conference on Plastering.

In most city building codes the specifications for wall plaster are

either very lax or entirely missing. To remedy this defect the Bureau has organized a conference for the specific purpose of writing a National Plastering Code. It is hoped that this work will be of such

quality that it will be accepted as a guide by the cit)^ legislators when

they frame their own laws on this subject. The conference is composed of official representatives of the Portland Cement Association,

the National Lime Association, the Gypsum Industries Association,

the National Association of Sand and Gravel Producers, the National

Brick Manufacturers Association, the Hollow Building Tile Association, the National Lumber Manufacturers Association, the Associated Metal Lath Manufacturers, the National Association of Plastering Contractors, the International Plasters' Union, the American Institute of Architects, the National Fire Protective Association,

and the Supervising Architects Office of the Treasury Department.

The work is well under way. The first chapter, having to do with

the preparation of masonry surfaces to receive plaster, is about ready

for the final action of the conference.

Physical Tests of Gypsum.

Certain methods of test for gypsum have been adopted as tentative standards by the American Society for Testing Materials. In

order to write specifications for gypsum, it is necessary to know the

numerical limits for the different properties, as measured by these

standard methods. To obtain this necessary numerical data, the

Bureau has measured the chemical composition, fineness, normal consistenc}', time of set, compressive strength, tensile strength, and 3ueld

of 43 samples of commercial gypsum products.

This report is now (July 1, 1920) in the hands of the Bureau's editorial committee.

Standards for Design of Reinforced Gypsum.

Tests of plain and reinforced gypsum beams, made between 1914

and 1916, led to the formulation of standards for the design of rein-
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 231

forced gypsum. These standards have been published in the 1919

Proceedings of the American Society for Testing Materials, vol- ume 19, part 1, page 319. Based upon this investigational work,

there has been manufactured and brought into use several millions

of square feet of reinforced gypsum tiles. This is a structural roof

tile used for supporting the ornamental tiles or other roofing materials. In practice it varies in span from 2-J- feet to about 10 feet. Some of its advantages are (a) lightness, (b) speed in construction,

(c) the furnishing of a nonconclensing surface for use in places

where large amounts of moisture are present in the air, and (d) its resistance to fire. The Cracking of Gypsum-Block Partitions.

Gypsum block is a comparatively new building material. In ac- cordance with the usual custom, therefore, any failure of a partition built of gypsum block is immediately blamed on the block

without further investigation. If the block does really cause cracking, the public should be warned; if it does not, the block manufacturer should have definite facts to combat the calumny.

The expansion and contraction of individual blocks when wet and

dry, hot and cold, loaded and not loaded, have been measured. A

partition 22 feet long by 10 feet high by 3 inches thick has been

built of gypsum blocks. Careful measurements of this partition and

of the concrete beams above and below it are being taken at frequent

intervals, so that if the partition does crack we shall have sufficient data to tell why.

Cooperation with the American Society for Testing Materials.

The work of the American Society for Testing Materials is chiefly

the preparation of specifications for materials, through special committees appointed to handle the individual subjects.

This section holds membership in committee C-3, on brick. It holds membership in committee C-7, on lime, and the chairmanship

of subcommittee 2 on structural lime and subcommittee 6 on plasticity. It holds the chairmanship of committee C-ll, on gypsum.

All of these committees meet frequently, and the Bureau is called

upon to develop test data for their use. Visits to Lime and Gypsum Manufacturing Plants.

In order to keep in close touch with the new developments in the

industry, and to obtain a first-hand knowledge of the problems con- fronting it, the practice has been started of making personal visits of inspection to the manufacturing plants. During the past year

28 lime plants and 1 sand lime brick plant in Maryland, Virginia,

and the District of Columbia have been inspected. Complete descriptions of the plants, illustrated with photographs, are kept on

file for future reference.
232 REPORT OF DIRECTOR OE BUREAU OF STANDARDS.

8. METALLURGY.

The metallurgical division concerns itself with research, investigation, and testing as related

to metals and alloys except metal structures and the processes of extraction of metals from

their ores. Its functions include the production of metals and alloys, both of the highest

attainable purity and of commercial grades; the preparation and study of auxiliary metallurgical products, such as slags, included gases, molding sands, refractories, and deoxidizers;

the development of apparatus, instruments, and manufacturing appliances for metallurgical processes, research, and testing; the formulation and maintenance of those standards and

specifications of interest to metallurgy; the determination of metallurgical constants and

properties; the investigation of the performance of manufacturing units; the determination of the causes of failure and the study of the improvement of metal products; and the develop- ment of economical metal substitutes. The division has equipment for metallographic examinations of metals, such as microscopic analyses, including determinations of constitution,

structure, and causes of failure; for thermal analyses, including determination of heating and

cooling curves for location of critical points; for the various heat treatments, such as annealing, quenching, cementation, tempering; for various operations for the hot and cold working

of metals, such as forging, rolling and drawing, and for miscellaneous physical tests; for the usual foundry operations of molding and casting ferrous and nonferrous metals; and for other metallurgical processes, such as production of pure metals, electrodeposition and

plating, welding, and determination of gases in metals. MICROSCOPY AND STRUCTURE.

Relation of Grain Size to Mechanical Properties.

Coarsely grained metals are usually regarded with suspicion and

alarm by users, though when pressed to the point but few are able

to give definite reasons for this distrust. A study has been started

to show the relation of the mechanical properties of steel to the grain

size of the same. As a measure of the " static " properties the Brinell

hardness was used, and the results of this part of the study have

already been summarized and presented for publication. Grain size appears to be of very minor importance compared with other factors

which affect hardness.

The work will be extended to cover the effect of grain size upon

the " dynamic " properties as measured by some form of the notchedbar impact tests. Conditions Affecting the Hardness of Carbon Steels. This study was planned partly to supplement the above ; it is also intended to make a close, careful study of the microstructural changes

which occur in hardened steels upon tempering. The data available

in the literature on this phase of the metallography of carbon steels are rather meager. By magnetic means, by thermal analysis, and

by a study of the physical properties of steel after tempering it can

be shown that pronounced changes occur in the steel. The microstructure does not show changes correspondingly as pronounced,

hence the need for a more careful study of steels in the hardenedand-tempered condition.

Intercrystalline Brittleness of Metals.

Metals sometimes develop a characteristic embrittlement so that

they can be easily crumbled into powder; the individual particles,

however, retain all the intrinsic properties of the metal. Such embrittlement may be due to various causes. The reason for such embrittleness in lead has been studied to considerable extent. (See

Publications. ) An unusual case of the embrittlement of copper has

also been described. Such embrittlement usually occurs as a result

of some form of corrosion, and a series of experiments have been

carried on to determine whether this embrittlement readily occurs during the corrosion of the common soft metals—lead, tin, aluminum,
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 233

etc. These experiments are still in progress; it appears, however,

that embrittlement most readily occurs if the specimen is subjected

simultaneously to corrosion and to a tensional stress. Metallographic Etching Reagents and Methods.

A rather comprehensive study of the subject of the etching of

metallographic specimens has been started in order to show what

principles underlie successful etching. This phase of metallographic

study has been developed in a rather empirical manner in the past.

The first metal to be considered in the investigation was copper ; the

results of this study are ready for publication. The successful etch- ing of copper depends upon two factors : There must be a slight sol- vent action and an accompanying oxidation. By varying the intensity of either of these two factors an " etching " varying from one showing bald contrast in the shades and colors of the different grains

to a simple etching in which the grains all appear alike may be obtained. The work is still in progress and is being extended to the

other metals and alloys.

" Deep Etching " as a Means for Metallographic Study.

This item was mentioned in last year's report as having been

started. The study was continued during the year, and the results obtained have been published. Deep etching as a means of macroscopic examination is of value in showing the following important

features: (1) Chemical inhomogeneity (segregation, etc.) , (2) mechanical nonuniformity (an internally stressed condition), and (3)

physical discontinuities (flakes, internal fractures, etc.) within the

steel. Structure of Iron and Steel at High Temperatures.

A knowledge of the structural condition existing in iron and steel at high temperatures is essential to a proper understanding of the

changes which accompany the hardening of steel by quenching.

Such a study has been carried out during the past year. The struc- ture existing at high temperatures was revealed by the means of

" heat etching " the polished face of the specimen ; after heating in vacuo at the desired temperature and then cooling in the eAr acuated

furnace, markings appear which are characteristic of the structural

changes it has undergone during the heating. It is unnecessary to use any etching gaseous medium at the high temperature, as has

usually been done in similar investigations.

The heat-etched specimens show a carbonless layer at the surface,

the thickness of which depends upon the conditions of heating.

Some further work has been planned in order to show the " mechanism " by which this decarburization in vacuo is brought about.

The Role of Manganese in Steel. As part of the investigation of deoxidizers for steel, a study is being made of a series of steels of Avidely varying manganese and

carbon contents. The aim of this part of the work is to show how

the structure of the iron-carbon alloy is affected by the presence of

different amounts of manganese. The specimens used will be taken

from bars for which the usual mechanical properties have been

determined.
234 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Zirconium and Other Special Alloy Steels. The study of the microstructure of " zirconium " and other special

alloy steels suitable for the development of light armor plate has

been completed. It "was the aim of the investigation to demonstrate

the role which zirconium and titanium play in such steels in the

endeavor to explain the effect of additions of these elements on the

mechanical properties of the resulting steel. It appears that neither

zirconimn nor titanium alloys with the steel but act as "scavengers."

When not eliminated in the slag the}7 remain in the metal as in- clusions. Of the other rare elements that were tried, cerium and

uranium go into solution in the steel while boron forms a complex

eutectic which is fusible at the temperature usually used in rolling.

A survey was also made of the microstructures of the plates in the

normalized and heat-treated states. This acted as a check upon

the soundness and heat-treatment of the plates, and in most cases served to explain unexpected mechanical properties.

Flaky Steel. The examination of the type of defective steel designated as

" flaky steel " was continued during the year. The results obtained,

however, do not add materially to our knowledge of the cause of this

defect in steel. Experiments with rolling steel of this character in

the Bureau's experimental mill showed that the flakes still persisted

after a reduction of 50 per cent. This was true regardless of

whether the rolling was in the direction of the defect or at right

angles to it. Conditions of Pearlite in Steel. This investigation, mentioned in last year's report, has been

completed. It was concerned principally with the structural conditions resulting in various grades of carbon steels after cooling the

heated specimen through the critical range (800-650° C.) at widely

varying rates. As an indication of the mechanical properties of

the materials the hardness was determined. The results are now

being assembled for publication.

Effect of Phosphorus in Low-Carbon Steels. A series of low-carbon steels (0.12 per cent carbon) with phosphorus varying in a series of five steps from 0.008 to 0.115 per cent have been used in this study. The aim is to determine the effect of the phosphorus upon the microstructure after amiealing, the

specimens being cooled at known rates through the critical range.

The mechanical properties, as indicated by the Brinell hardness, are

also determined. The steels used are those described by Dr. J. Unger.

Carnegie Steel Co., in Iron Age, 1918, and represent both acid and

basic open hearth practice. The investigation is still in progress. Electric-Arc Welding.

Though seriously handicapped in the study of welding by several

resignations during the year, a rather comprehensive study of the

properties of the " weld-metal " of electric arc welds has been made.

A large number of specimens of arc-fused metal were prepared from

two of the types of metallic welding electrodes now used for the pur-
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 235

pose, of a size large enough to permit a study of the characteristic

properties of the material being made. This study included the determination of the mechanical properties, the changes induced in the

chemical composition by the fusion, and the examination of the

microstructure of the fused material. Particular attention was

given to the subject of nitrogen in such material, the condition in

which it occurs, its determination, and its elimination. Electric-arc

welds are essentially castings and should not be used for any purpose for which a casting would be unsuitable. The results of the

investigation have been summarized and submitted for publication

as a technologic paper.

Copper Crusher Plugs.

The results of the experiments on copper crusher cylinders con- ducted so far have been prepared for publication. As a result of the

research completed there have been drawn up four specifications cov- ering the standardization of pressure gauge method of pressure test- ing of ammunition and powder, as follows: (1) For copper rods to be

used in the preparation of pressure gauge cylinders, (2) for the

preparation of pressure gauge cylinders, (3) for the calibration and

precompression of copper cylinders, (4) for standard methods of

making pressure tests. HEAT TREATMENT AND THERMAL ANALYSIS.

New Equipment.

Several small heating units have been added during the past year

to the experimental heat treating plant and an automatic temperature control pyrometer has been purchased. The section is now well

equipped with a number of heating furnaces of a variety in size and

design enabling efficient heat treatment of carbon, alloy structural

and high-speed tool steels, and also nonferrous metals and alloys to be carried out. Effect of Heat Treatment on Properties of Structural Steels. There is in progress a series of investigations to determine the

effect of heat treatment on various physical properties of carbon and

alloy structural steels. One of this series, namely, stainless steel, con- taining 0.20 per cent carbon and 13 per cent chromium, has been

completed, while progress is being made on others as outlined below.

One Per Cent Carbon Steel.—Tests are now in progress to determine the effect of time and temperature in both hardening and tempering on structure, tensile properties, hardness, and impact resist- ance of a 1 per cent carbon spring steel. Three and One-Half Per Cent Nickel Steel.—This investigation

consists of a correlation under varying thermal treatments of tension,

compression, torsion, fatigue, and impact properties as determined

by various types of testing machines, with structure. Considerable

data are available concerning this widely used steel, but there is no known correlation of mechanical properties such as is being at- tempted. The actual work involved is now about half completed,

but no conclusions have been drawn. It is expected that this investigation will be completed during the coming year.
236 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Carbon Chromium Steel.—An investigation on the effect of heat

treatment on the compressive strength and wear resistance of a steel containing 1.10 per cent carbon and 1.40 per cent chromium is now

under way. This steel is largely used in the manufacture of balls and

races in ball bearings and the tests contemplated, comprising compression, impact, and wear resistance, should be of particular interest to this field. Molybdenum Steels.—Steels containing molybdenum are again

arousing considerable attention for use as structural materials, particularly as considerable deposits of ores of this metal are to be found

in this country. A series of tests on various alloy steels to which

molybdenum has been added has been started to determine the effect of heat treatment on structure and tensional and impact properties.

High Chromium Steel.—The experimental work in this investigation has been completed and a paper published in the July Journal

of the Society of Automotive Engineers and in the July 7 issue of

Chemical and Metallurgical Engineering.

The following features are of particular interest : Samples of a high chromium steel of the following analysis, C 0.29 per cent; Mn

0.38 per cent; Si 0.70 per cent; and Cr 13.2 per cent, quenched in oil from various temperatures show (1) that with increasing quenching

temperature hardness as measured by Brinell and Shore instruments

increases until a temperature of about 1,950° F. (1,066° C.) is reached. Maximum range of hardness is generally obtained by

quenching from this temperature up to the highest heat used, but in some cases this hardness actually decreases due to retention of the

solid solution; (2) that quenching from about 1,750° F. (955° C.)

develops the best combination of strength and ductility which is not coincident with range of maximum hardness. Quenching from

this or lower temperatures does not retain all the carbide in solution

as is the case in samples quenched from considerably high temperatures (notably 2,100 and 2,250° F.) (1,149 and 1,232° C.) ; (3) and

that ductility as measured by elongation and reduction is very low

in those samples quenched from 1,850° F. (1,010° C.) or above.

Short-time tempering at temperatures up to about 800° F. (427°

C.) of samples previously quenched from both 1,750° F. (955° C.)

and 2,100° F. (1,149° C.) decreases brittleness. However, ductility

is increased to a greater extent in those samples quenched from l,750u F. (955° C.) than in those quenched from the higher temperature.

Tempering above 800° F. (427° C.) markedly decreases strength

values and hardness, which is of course accompanied by greatly in- creased ductility. In general, the structure of the hardened steel tends to persist even when tempered for a short period of time at temperatures comparatively close to the lower critical range, the

characteristics depending upon the quenching temperature used.

The most rapid change in tensile properties and hardness occurs in

tempering between about 800° and 1,000° F. (437° and 538° C).

Tensile Properties of Steels at High Temperatures.

During the year a special apparatus was designed and constructed

for the determination of the proportional limit at elevated temperatures. Over 300 tensile tests of boiler plate of various grades and

under varying conditions of work and thermal treatment were made

at temperatures up to about 460° C. A preliminary report of the
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 237

first two series of tests has already been published by the American

Institute of Mining and Metallurgical Engineers, and another and more complete publication is expected within the coming year. Tests on marine and tAvo grades of fire-box boiler plate have been completed. Plates have also been tested as cold rolled and quenched and

tempered in various ways. A modification of the apparatus using a motion-picture machine for obtaining stress-strain diagrams at rapid

rates of loading at elevated temperatures has also been constructed

and used with success. Confirmation of generally accepted changes in tensile strength,

elongation, and reduction in area were found. Tests further show

that proportional limit does not decrease with temperature rise, as has often been stated, but that this factor " holds up " throughout a

definite temperature range and in some cases increases before final decrease occurs. Eate of loading from less than 0.01 inch per minute to 1.6 inches

per minute has practically no effect on the tensile properties (including position of proportional limit at temperatures up to and including the blue-heat range about 295° C). At 466° C. some interesting changes take place. Further work confirming these results is now being carried on. Bluing of cold-worked steel (annealing for a short time at 295° C.)

markedly increases the ratio of proportional limit to tensile strength.

Similarly, low temperature annealing of steel rolled at a blue heat

(295° C.) does not show this effect. These experiments are being

continued.

Heat Treatment of Carbon Steel. In cooperation with the National Research Council and the Bureau

of Mines, an investigation has been begun to increase our knowledge

of the production of sorbite, both by determining the limits of the

sorbitizing conditions and by showing the influence of the more

important variations of the tensile and impact properties of the

resultant sorbite. Material treated consists of seven-eighth-inch

rounds of acid steel, with carbon contents 0.34, 0.52, and 0.75, and

above 0.50 manganese. They are being heat treated under especially

favorable conditions for effect of reproduction and the resulting

properties of material determined. It is expected to be able to report substantial progress the coming year. Behavior of Hardened Carbon and Alloy Steels on Heating.

Determination of the effect of heating previously hardened car- bon steels has been made. A thermal transformation act coincident

with precipitation of the carbide held in solution by the previous

quenching has been investigated and a publication has been pre- pared. Considerable progress has also been made in determination

of the effect of various alloying elements such as Mn, Si, Mo, W, Co,

etc., on this transformation.

High-Speed Steel. Preparations have been made to obtain a small lot (about 10

pounds) of high-speed steel from 10 manufacturers of high-grade

standard high-speed steel. Seven have already complied and six

samples are at present undergoing chemical analysis. The purpose
238 EEPOET OF DIBECTOE OP BUEEATJ OF STANDARDS.

of this investigation is to obtain accurate information as to the

proper heat treatment of high-speed steel and to correlate such data

with the composition; it is planned to include determination of

fusion temperature and degree of secondary hardening. Such in- formation should be of considerable importance in aiding in the

explanation of the effect of the several allojdng elements and the reasons for their control within the usual narrow limits of practice.

Gauge Steels. A preliminary series of length and flatness measurements covering

six months has been completed on several hundred artificially sea- soned steel precision gauges of varying compositions subjected to various treatments. Results obtained have not proved satisfactory

as the changes in individual gauges subjected to the same treatment

are inconsistent in most cases, which seems to approximate conditions in use. Continuation of this work during the year is con- templated.

High-Speed Cutting Alloys.

Determination of the tensile properties of several so-called highspeed alloys at elevated temperatures is also in progress with the

view to correlating cutting efficiency with properties more simply

determined, giving if possible an index to the relative values of

various steels (or of the same steel after various treatments) as cutting media for specific purposes.

Thermal Analysis.

Considerable progress has also been made in various investigations where determination of thermal transformations is the principal method employed. These are as follows:

Iron carbon alloys.—The experimental determination of the

thermal transformations of pure iron-carbon alloys of fundamental

importance in the heat treatment of steels (as outlined in the last report), has been completed and a publication is now in preparation.

Nickel Steels.—Experimental work and a publication covering the

effect of nickel up to about 5 per cent on the occurrence of the thermal

transformations has been completed.

Embrittling Effects of Cleaning and Pickling Upon Carbon Steel. This investigation, described in last year's report, has been completed and an account of the results read before the April meeting of

the Electrochemical Society and will appear in the fall in a forthcoming technologic paper. The embrittling effects were obtained for

plain carbon steel rods by the alternating stress method and of plates

by the Erichsen penetration method. The effect of cleaning, sand

blasting, pickling, and treatment after pickling were studied.

WORKING OF METALS AND MISCELLANEOUS PROPERTIES.

Bearing Metals.

During the latter part of the year a start has been made on the

bearing-metal program mentioned in the annual report for 1919. Apparatus has been designed and constructed for determining the
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 239

proportional limit in compression, compressive strength, and Brinell

hardness at elevated temperatures. Results have been obtained for

these properties of the bearing metals included in the revised specifications of the Society of Automotive Engineers at temperatures of

25°, 50°, 75°, and 100° C. and are now being prepared for publication.

A review of the literature on bearing metals has been made and a bibliography compiled. This, together with some miscellaneous tests on bearing metals, will also be published shortly. Other items on the

program will be taken up as fast as the vailability of funds and per- sonnel permit.

New Foreign Alloys.

Through the courtesy of the Bureau of Foreign and Domestic Commerce and the Department of State the Bureau has had opportunity

to study some recent alloys developed abroad and for- which most re- markable claims have been set forth in the popular and technical

press. Tests made at the Bureau do not show these materials, most of

which are aluminum alloys, to possess any superiority over American

made alloys, and in many respects are inferior.

Acid-Resisting Alloys. Tests of typical acid-resisting alloys of the silicon iron type ex- posed to the action of various acids and salt solutions at atmospheric

and elevated temperatures are in progress. Since the exposures are

relatively long and the hot tests can be conveniently made only during the winter months, when the steam supply is continuous, the

results of this investigation will not be available for several months.

Mechanical and physical properties of the materials are also being

determined.

Cushman Zinc-Coating Tester. A study was made of the original form of an apparatus devised

by Dr. A. S. Cushman for determining the weight of zinc coating on

galvanized sheet. The apparatus consists of a bowl held tight to the sheet which contains a solution of antimony chloride in hydrochloric acid and an inverted burette to collect the gas set free by the

reaction. The results were quite variable and inaccurate, due to the

irregular expansion of the entrapped air. The apparatus has since

been improved by Dr. Cushman to eliminate this error, and in its present form is a very convenient and rapid device for determining

the weight of zinc coatings.

Equilbria of Tin Rich Ternary Alloys.

An investigation was made of the ternary alloys high in tin, of

tin-copper-lead, tin-copper-zinc, tin-copper-antimony, tin-lead-zinc,

tin-zinc-antimony, and tin-lead-antimony. Freezing point determinations were made on these allo}T s, which contained from 0.1 to 1.0 per cent of each of the elements added to the tin. Some of the alloys

contained equal amounts of the impurities and others unequal

amounts. From the freezing-point determinations, diagrams showing the freezing points of each system of ternary alloys were made

from plaster of Paris and these models photographed. The freez- ing-point determination showed that the effect of the impurities was

not individual, additive, or substractive. They also indicated the
240 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

effect of the impurities on the freezing point of tin as used in the

testing of fusible plugs. A few photomicrographs were taken of

each of the series of ternary alloys showing typical microstructures.

A publication is in course of preparation.

Metal Specifications.

Assistance has been given to Government departments and technical societies in the formation of specifications for metallic materials. Mention may be made of the Navy Department, War Department, Panama Canal, District of Columbia, Society of Automotive Engineers, American Society for Testing Materials, and the

National Advisory Committee for Aeronautics. An interdepartmental committee has requested the Bureau to act as a clearing house

for specifications, and to this end a complete file of all Government

specifications and many commercial specifications is being collected. New Equipment.

The following new equipment of interest has been acquired during

the year : 50,000-pound Amsler universal testing machine, Farmer

alternating stress machine, Stanton alternating impact machine,

Amsler wear-testing machine, 200-pound wire-testing machine, and

an Ewing extensiometer.

Precision Altimeter.

In cooperation with the aeronautic instrument section an altimeter

of unusually high precision has been developed. This altimeter has

a range of 10.000 feet and a maximum error, due to hysteresis of 20

feet, or 0.2 of 1 per cent. The drift and after effect are negligible.

This instrument was made possible by the development of a steel spring of exceptional qualities having a maximum deflection without

exceeding the true elastic limit of the material used.

It is expected to publish soon a report covering the development

of this instrument and precautions to be followed in the design of

similar instruments.

Rolling and Forging of Metals.

The following metals have been rolled during the past year ; forty

ingots of zirconium steel rolled to one-half inch plates, 69 ingots of

iron alloys rolled to one-half inch plates, boiler plates rolled cold

and at "blue heat.'' specimens of flaky steel forged and rolled, and

specimens of steel annealed in vacuo. Two hundred pounds of lead in the form of 50-pound pigs were

forged and rolled to sheet 0.03 inch thick for the Research Laboratory

of the Signal Corps. Samples of these and other sheets were an- nealed at various temperatures and duration in an effort to determine

the best procedure for producing lead for some electrolytic cells. Emissivity of Monel Metal and Constantan.

At the request of the International Nickel Co., the emissivity of

several samples of molten monel metal was determined. Five observations were made in an atmosphere of C02 with the micropyrometer. The emissivity was found to be 0.40±0.01 at 1,400° C. with

a wave length of 0.65^.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 241

The emissivity of constantan with the same conditions Avas found

to be 0.38. Observations of monel metal heated in air, giving an

oxide surface, gave a value of the emissivity of 0.70±.02 at 1,200° C. Rolling-Mill Investigation.

In this investigation the effects of the properties of hot-rolled

steel produced by variations in some factors of the process of rolling- are to be determined. The factors to be varied are : Reduction per

pass, total reduction, finishing temperature, initial temperature, and

speed of rolling. Observations will be made on the power con- sumed by the mill with the different conditions of operation thus

produced.

The effects on the mechanical properties of the material are to be observed by longitudinal and transverse tensile, impact, Brinell,

and scleroscope hardness tests on each sample in the rolled condition and after normalizing. Fatigue tests will also be made on

some of the samples. Observations will be made of the density

of the material as cast and with various conditions of rolling. Examinations of the microstructure will be made to assist in the interpretation of the results. Physical Properties of Pure Nickel.

The object of this investigation is to determine the physical properties of pure nickel; to date the determinations have been only on

samples which can not be classed as pure nickel, although meltingpoint determinations to some extent have been taken on pure nickel.

Following successful working of pure nickel, the determination of the

following physical properties is planned on material as cast, forged

or drawn, and annealed : critical points, density, linear expansion,

electrical resistance, and mechanical properties. Material for this

work is being prepared by the International Nickel Co.

Corrosion of Aluminum Alloys.

Exposure tests were made at the three navy yards, at Portsmouth,

Norfolk, and Pensacola, of sheets of aluminum, duralumin, and

various other metals, both painted and unpainted, to determine the

resistance to sea-water corrosion between sand and water. The re- sults of these preliminary experiments are somewhat in doubt due

to the unexpected presence of fuel oil on the sea-water surface. The

aluminum and duralumin plates showed very little corrosion to these

conditions and the effect of painting was negligible.

RAILROAD MATERIALS.

Steel Rails from Ordinary and Sink-Head Ingots.

The opportunity was given by the Pennsylvania Railroad Co. to carry out an investigation of the quality of steel rails from various

types of ingot with the cooperation of two steel companies. This

work is in press as a Bureau technologic paper.

The research involves a comparison of 100 tons of Hadfield sinkhead ingots and of ordinary rail ingots as made by the Maryland

Steel Co. with three methods of manufacturing steel, and includes a chemical, physical, and metallographic survey of the ignots and of

10613—20 16
242 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

the blooms and rails made from them. It was found that sound rails free from piping and segregation with a very small discard could be

made from the sink-head ingot. This type of ingot appears to be

much more satisfactory for making sound rails than that of the ordinary type, cast with the small end uppermost.

Chemical analyses and sulphur prints of split ingots and blooms,

metallographic investigation, and a large number of the usual mechanical tests are included in the report. Several tests by the Pennsylvania Railroad Co. showed no breakages in two j^ears.

Cast Iron for Locomotive-Cylinder Parts. The former United States Railroad Administration requested the

Bureau to investigate the quality of cast iron used in locomotive packing rings and other cylinder parts subject to the action of superheated

steam. The Railroad Administration procured a number of rings

made by different foundries with service mileage records, as well as arbitration test bars and chill test blocks, also from various makers.

The resutls, which have gone to press as a Bureau technologic paper,

indicate that on the average air furnace iron, because of its some- what better quality and more uniform character, is more suited for

cylinder parts than cupola iron.

Existing specifications have been revised so as to make the mechanical requirements more rigid and assures the use of only the

highest quality of iron. The Bureau believes that as long as the

materials meet the requirements of the specification the consumer

need not be concerned with the melting process employed.

Thermal Stresses in Chilled-Iron Car Wheels.

The experimental work on thermal stresses induced in chilled iron car wheels by heating of the tread similar to that caused by brake

action has been completed. Records of the railroads indicate that

a very large percentage of ear-wheel failures are due to heating

of the tread in service, the hub of the wheel remaining relatively cool. It was the purpose of this investigation to determine and recommend

for use the most suitable material and design for iron car wheels.

Fifty wheels were used for the investigation.

In these experiments the tread of the wheel was heated by passing an alternating electric current through a circular steel resistor insulated from the tread. The wheel remains stationary, thus facilitating

the taking of the necessary temperature and strain gauge readings.

A large percentage of the wheels cracked in the test, indicating it to be more severe than service conditions. An interesting and significant development of the work was that the high sulphur wheels

showed a much higher percentage of failures than those of lower

sulphur content. The results in detail will soon be published as a Bureau technologic paper.

Thermal Stresses in Steel Car Wheels.

It has been decided to conduct an investigation of steel car wheels

similar to that of iron car wheels. On June 17, 1920, a meeting of

the representatives of manufacturers, one railroad, and the Bureau was held at Washington. At this conference the results of the tests of iron wheels were discussed, and as a first step it was thought de-
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 243

sirable to first duplicate on steel wheels the tests of iron wheels. Both new and used wrought and cast steel wheels are to be tested. Graphitization of White and Gray Cast Iron.

It has been found necessary to continue the Bureau's work 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. The composition of the wheel

is so chosen and the wheel so cast that the tread and inside of flange

show white iron and the remainder graphitized 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 and allowed to cool slowly; investigation developed the fact that the highest temperature at which no graphitization of the tread and flange takes

place is about 720° C, which is also the maximum annealing temperature for car wheels. Arrangements are being made to determine the

effect of annealing at low temperatures for a prolonged period of

time.

Electric Furnace Cast Iron Experiment.

The problem of refining molten cupola iron in the electric furnace

has been brought to the attention of the Bureau by the Association

of Manufacturers of Chilled Car Wheels. The Bureau first plans to remelt low quality scrap with the object of determining the quality

of the product. Chill tests and the usual mechanical and chemical

tests will be made. The small Heroult electric furnace is admirably

adapted to this type of research.

Sulphur and Phosphorus in Steel. During the war it was found practically necessary to permit the

use of steel for railroads and other purposes containing larger

amounts than was considered desirable of the detrimental elements,

rjhosphorus and sulphur. At the request of the former United

States Bailroad Administration and the American Society for Test- ing Materials, an elaborate program has been prepared by a joint

committee of which the Bureau has the chairmanship, and on which

practically all of the larger technical societies of the country are

represented. It is the object of the investigation to determine the

maximum permissible amounts of phosphorus and sulphur 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.

On account of the present unsatisfactory fuel and scrap situation the

problem is one of acute importance, especially in the reference to sulphur.

Under the auspices of the joint committee on the investigation of

sulphur and phosphorus in steel, a beginning has been made in the

collection of statistics concerning the behavior in service of steels containing unusual quantities of sulphur or phosphorus and the

following program of tests has been laid out.
244 REPORT OF DIRECTOR OF BUREAU OP STANDARDS.

SERIES A TESTS.

SI7LPHLT3 IN ALT. STEELS TO EE " ReSIDTJAX StJEPHTJB."

[All compositions are expressed in hundredths ol per cents.]

—Group

XT „ JNO. Material. Carbon. Manganese. Phosphorus.1 Sulphur.1

1 Rivet steel, tubes, etc 6-12 35-40 2-3 3-4

4-5 5-6

6-7 7-8 2 Plates and structural shapes, including boiler plate .

.

16-22 35-40 3-4 3-4

5-6 5-6

7-8 7-8

3 Forgings, such as car axles, treated and untreated 45-55 50-60 3-4 3-4 5-6 5-6

7-S 7-8 4 Wheel, tire and rail steel 65-75 60-70 3-4 3-4

5-6 5-6 7-8 7-8 5 Spring steels 95-105 35-45 2-3 3-4

4-5 5-6

6-7 7-8

6 Castings Compositions to be considered later.

1 "With each of the specified ranges of phosphorus it is understood that the sulphur content is to be constant and equal to the usual valua for that group of material. (Vice versa for sulphur.)

SERIES B TESTS.

In these tests higher percentages of phosphorus and sulphur than

are specified in Series A tests shall be used. The purpose of this

series is to carry the tests beyond the percentages of impurities specified in Series A to a point where the material will unquestionably fail from the effect of the higher impurities.

There have been made for the committee 12 tons of rivet steel, part

of which has been made up into rivets and part into bars of varying

sulphur content which are now being tested in the Government lab- oratories at Watertowii, Annapolis, and the Bureau of Standards.

There have also been made under the class B series three heats of steel of three carbon contents, each consisting of eight sulphur contents,

totaling 63 tons, from which it is expected to obtain evidence as to the effect of sulphur both as added between the ladle and the ingot

and as residual in the beat.

CHEMICAL METALLURGY.

Iron-Carbon-Manganese Alloys.

The preparation and analyses of ingots of the original series planned for this investigation have been completed ; also a partial sec- ond series of similar composition for heat treatment. Most of the

bars for mechanical test have been prepared and several of these have

received final heat treatment preparatory to mechanical test. Magnetic test specimens have also been prepared.

Direct Method for Determining Nitrogen.

I he work described in the last annual report on a new method for

determining nitrogen as such or in mixtures with other gases has

been continued on an increasing scale and the apparatus brought to

its final form. As a result of improvements thus effected, the time
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 245

equired for a determination has been reduced to less than two hours,

t is expected this investigation will be published during the coming

ear. itrogen in Weld Metal.

Determinations of " combined " nitrogen by the Allen method, as modified in the Bureau, have been made on samples of weld metal de- osited by the arc under experimentally varied conditions. Deterinations have also been made on the same samples after heat treat- ent in vacuo and under ordinary atmospheric conditions. Very

arge amounts of " nitride" nitrogen (up to 0.15 per cent) have been

found. These are reduced somewhat by heat treatment, especially in vacuo. It is planned to make total nitrogen determinations on these same samples, using the new direct method for this element that has

been developed in the section on chemical metallurgy.

New Design for Arsem Furnace Heater.

The heater heretofore used in the Bureau's Arsem furnace is a carbon spiral, which is fragile and is usually ruined if molten iron comes in contact with it, as frequently happens. To obviate this,

difficulty a tubular heater was built up of superimposed carbon rings,,

these being mounted in the ordinary electrode holders used in the

Arsem furnace. Preliminary trials of this furnace have been successful. Such heaters were used and described by Rosenhain at the

National Physical Laboratory for furnaces working in reducing or

inert atmospheres, and the results here show that the design is equally

well adapted to vacuum furnaces. A paper describing this furnace

is being prepared.

Ladle-Test Ingot Research (in cooperation with the A. S. T. M.).

Ten steel companies are cooperating in the work this year. The

purpose of the work now in progress is to investigate more completely the findings of the last report, namely, that the addition of

aluminum to ladle-test ingots while they are being poured eliminates

segregation regardless of shape and size of ingot. Each of the companies is preparing ingots from heats of carbon steels with varying

compositions, first, according to its usual practice and, second, by

the usual practice except that aluminum is added. Six of the companies have completed their work. When all the ingots have been

received they will be examined chemically and physically at the

Bureau and elsewhere.

Aluminum.

The work previously reported on preparation of pure aluminum

has continued and several specimens have been made under varying

conditions. The electrically heated furnace for maintaining the

cryolite bath in the molten condition was very successful and some

methods were developed for purifying the raw materials beyond the

point reached by the manufacturers. It is expected to continue this

work next year. Total Gases in Steel. During the year a new method has been developed for this work,

which aims to dispense with sample collecting or other complicated
246 REPORT OF DIRECTOR OE BUREAU OF STANDARDS.

mercury pumps. The gases liberated from the molten steel are aspirated through a suitable set of weighed absorption tubes connected

to a simple mechanical vacuum pump. Tests of this method on gas

mixtures of known composition have given very good results. Special Refractories.

A considerable amount of work has been done on refractories

necessary for the special requirements of the section, particularly in

the use of ^irkite alone or mixed with other materials and various

binders for crucibles and gas-furnace linings. The method for

making magnesium oxide by calcining the sulphate has been fully

developed and has superseded other methods used in the section for

this purpose. In order to obtain the oxide entirely free from sulphur

it has been found desirable to leach it with water after calcination.

This material is now prepared and used in relatively large amounts

for the alloy work.

Deoxidizer Investigation.

The first phase of the cooperative research on this subject with the

National Research Council and others has been completed and is about to appear in the technical press. In this work 73 possible new deoxidizing alloys were discovered, and the preparation of these

is noAv initiated. When made they will be tried out in the Bureau's

experimental steel-making furnace and elsewhere.

New Equipment.

The Ajax-Northrup furnace mentioned in the last report has been

used in many phases of the alloy work and is to have further application in the work on gases in metals. A new Arsem furnace, using

the modified Rosenhain heater previously mentioned, has been added

to the equipment for this work. Additional capacity for making

electrolytic iron has also been provided. The small furnace (run as an open-hearth furnace) for steel melting has been installed and

operated.

FOUNDRY.

Experimental and Practical Castings.

During the past year there has been a marked increase of service

given by the foundry to the Bureau and research laboratories of

other Government departments in the preparation and making of a great variety of kinds and types of metal and alloy castings. The

total estimated value of castings furnished during the year was

$7,395. During the year there were made 1,946 castings from 401

patterns.

Molding-Sand Investigation.

The various commercial grades of foundry sands are being studied

and include sieve tests, determination of optimum water content,

permeability, and melting points, in order to determine their fitness for foundry purposes.

Weathering of Art Bronze.

An investigation is being carried out in cooperation with one of

the statuary manufacturers as reported in the last annual report.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 247

The purpose of the research is to determine the relation of the composition of statuary bronzes to the facilities with which they assume

patinas on exposure to weather. The specimens have been undergoing weathering for some four years.

Electric Melting Furnaces.

The two electric furnaces which form part of the equipment of the

metallurgical laboratory have been put to practical tests and found

successful in manufacturing iron and steel for alloy-steel research.

It was found to be possible to conduct in these furnaces refining processes as in any electric furnace.

There have been also manufactured several " Invar " pendulum

parts.

Government Bronze and Its Substitutes.

The results of the first series of tests on substitutes for Government bronze have been published and a second series has been begun and is still under way, using 88-10-2 and 88-8-4 as a basis. Additions were made of Al, Fe, Sb, Mn, Ni, Mg, etc., to determine the

effect upon the physical properties of such alloys. The work has

not progressed sufficiently to show any definite results ; it is expected

to complete this during the coming year. MILITARY PROBLEMS.

Light Armor Plate.

This investigation, which was carried out in cooperation with the

Bureau of Mines and the INavy Department, has been completed during the year, and a publication dealing with the results obtained is in preparation. The work was undertaken primarily to determine the

effect of zirconium as an alloying element in steel and indicates that

the addition of zirconium does not increase the mechanical properties of the steel above that obtainable with cheaper and more simply

manipulated alloying elements. Much the same statement applies

to the use of molybdenum, uranium, cerium, boron, and copper in

this type of steel. The most consistently good results were obtained

with a steel containing from 0.40 to 0.50 per cent carbon, 1 to 1.30 per cent silicon, 0.80 to 0.90 per cent manganese, and 3 to 3.5 per

cent nickel, with the possible addition of a scavenging element as vanadium. Such a steel gave a tensile strength exceeding 300,000

pounds per square inch, yield point of 250,000 pounds per square

inch, with an elongation of 10 per cent and reduction of area of 35

per cent. About 1G5 heats of steel produced at the Bureau of Mines

Experiment Station at Ithaca, N. Y., have been rolled into plates

at the Bureau, heat treated, and the various properties determined.

Twenty-eight heats submitted by a manufacturer were also included.

Ballistic tests are being conducted on the material by the Navy Department.

Machine-Gun Erosion.

During the past year a number of machine-gun barrels furnished

by the Ordnance Department were subjected to various tests to throw

further light upon the relative abrasive action of the bullet and the

gases upon the bore. Examination of barrels fired for varying num-
248 REPORT 03? DIRECTOR OF BUREAU OF STANDARDS.

ber of rounds to and beyond a so-called life limit reveals the importance of both the abrasive action of the bullet and the gases. This

series of tests has also included the intentional cracking of small

specimens by means of an electric arc. A paper covering this pre- liminary work is now in preparation.

Continuation of experiments to determine more exactly the abrasive action of the bullet is contemplated during the coming year. A

series of 21 steels of varying compositions was made up into billets and specially treated and are now undergoing ballistic tests by the

Army Ordnance.

Copper Crusher Gauges.

This study, which was mentioned in the last annual report, has

been completed and the results embodied in specifications which have

been tentatively adopted by the Ordnance Department.

Metal Spraying.

An investigation of the latest devices for metal spraying is now

under way and new designs for such appliances are to be worked out. Manufacture of Victory Medals.

In cooperation with the chemistry division and the Quartermaster

Corps of the Army a member of the metallurgical staff visited plants

of manufacturing jewelers in Seattle, Wash., and St. Louis, Mo., who

were about to produce Victory medals, which are to be given to all American participants in the World War. The metal to be used was

inspected and advice given in regard to the manufacture and color- ing of the medals.

German Motor Trucks.

The Motor Transport Corps has requested the Bureau to study

the quality of the materials used in the construction of a large number of German motor trucks which were either captured during the war or turned over to the United States Army after the declaration of

the armistice. Although the examination is not yet complete, the

parts so far studied do not differ greatly from similar parts produced in this country. No remarkable substitute materials have been

noticed, although in the majority of cases it is impossible to determine whether the trucks were constructed before or during the war. RESEARCH AID TO MANUFACTURERS.

The following will give an idea of the kind of research aid it has

been possible to give manufacturers during the past year. The list

is not complete ; but a few of the typical cases onty are given.

Wrought Monel-Metal Parts.

It was shown by suitable microscopic examination that the defects

which were suspected as being developed by service conditions were

initially present in the metal and had persisted throughout the

shaping of the piece. The persistent character of the " work line "

in nickel alloys and their relation to the defects in the specimens

under examination rendered the explanation one of absolute cer- tainty.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 249

Die-Casting Pins.

Steel parts used for die-casting parts often quickly deteriorate in

service, due to the formation of a network of " alligator cracks," very

similar to those formed in the erosion of the bore of gun barrels. Any grade of steel will ultimately deteriorate under the application

of heat and pressure. The examination of the particular specimens

submitted showed, however, in this case that defects initially present

in the steel (ferrite streaks, inclusions, etc.) were sufficient to account

for the abnormally short life of the parts.

Saw Blades.

A comparison of small jewelers' saw blades of present American

manufacture with similar blades of prewar foreign make was re- quested by a large firm of jewelers. The examination made clear that

the American saws were made apparently without a clear understanding of the purpose for which they were intended. Though

of a different composition from the foreign-made blades, it was shown that by proper heat treatment a material improvement could

be brought about.

A series of band-saw blades were submitted by another manufacturer. The examination showed that steel of a very inferior quality

had been used, probably unknowingly. The defects in the blades were the direct result of similar defects present in the steel from

which they were rolled. Tinned Plate.

A series of specimens of " tin plate " of American make intended

for export trade for the canning industry, but rejected by the purchasers as unsatisfactory were submitted for test. The examination

showed that the steel sheet used as a base was of very inferior grade,

and in most cases had received insufficient heat treatment for the

stamping and other forming operations for which it was being used.

Automatic Knitting-Machine Needles.

Prior to the war the majority of automatic knitting-machine

needles were imported from Germany, and during the war considerable difficulty was experienced in producing satisfactory needles in

this country, although at present at least one manufacturer is making

needles superior to the German ones. At the request of one of the

manufacturers the Bureau is making a study of the various makes

of needles in order to determine what qualities the needles must

possess in order to prove satisfactory in service and so that specifications for their manufacture can be formulated.

Manufacture of Automobile Crank Shafts.

At the request of a maker of 6-throw automobile crank shafts the

process of manufacture was studied with the idea of eliminating

certain difficulties which had been encountered. It was found that

much of the trouble was of a mechanical rather than metallurgical

nature, although opportunities were found for various improvements

in this end of the process. A report, giving the Bureau's conclusions in the case, was issued for the benefit of the manufacturer

interested.
250 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

GENERAL ACTIVITIES.

Metallurgical Tests. During the j^ear the division makes a great many tests for both

parties inside and outside of the Bureau, some of an elaborate nature

and others being of a routine nature. Fusible Boiler Plugs.—Six hundred and fifty-five fusible plugs were tested for the Steamboat-Inspection Service ; of these 418

passed the requirements, 191 were rejected, and 46 were reported for

having loose fillings. Of the 191 unsatisfactory plugs, 114 were re- jected for having mare than 0.30 per cent Cu; 26 for having 0.30 per

cent Cu and 0.10 per cent Pb; 16 for having more than 0.10 per cent Pb; 6 for having more than 0.30 per cent Cu and more than 0.10 per

cent Pb and a trace of bismuth; 4 for having more than 0.10 per cent of Fe; 24 for having melting points below 230° C. and 1 for having

sand in the tin filling.

Stainless Steel.—Samples of stainless steel for use for parts ex- posed constantly to sea water were examined. The test included

microscopic examination, heat treatment, and exposure in a corroding

atmosphere of a series of typical stainless steels. The results indicated that steels of a high chromium content were most resistant to corrosion and also that when in the hardened (heat-treated) state the attack was less than when in the soft (annealed) condition.

Cast-iron Locomotive Packing Rings.—A large number of these were examined for the Railroad Administration. The results of the

microscopic examination with those of the other tests made were embodied in the publication on this subject.

Steel Casting.—The examination of a large steel casting intended

for a rudder frame Avhich broke during transportation showed that

although the material had received the specified heat treatment for

refining, the coarse " casting structure " still persisted. This was

due to the impurities present. Heat treatment has no effect upon the

relocation of these ; they remain in their original distribution and so the material retains to a large extent the original properties of the

cast material.

Use of Cyanide Baths for Hardening.—A series of examinations

for one of the departments of the Government of soft plates de- signed as " casehardened in cyanide " showed that no appreciable

hardening results from the cyanide. The vigorous water quenching

which follows the heating in the cyanide bath is sufficient to account

for the hardness. The function of the cyanide, as thus used, appears

to be the prevention of scaling or oxidation of the carefully prepared

surfaces of the soft steel plates.

Among other examinations made may be mentioned the splitting

of antimonial-lead-cable sheathing due to streaks (apparently of

oxidized material) ; the progress of corrosion of thin castings of

aluminum alloy used on seagoing hydroplanes, copper rotating

bands, wrought-iron parts, in the endeavor to determine whether

" single " or " double " refined ; the failure of airplane turnbuckles

due to the use of steel of a highly streaked character; steel bayonets

of different designs ; articles claimed to be of " sterling silver " composition; bearing metals which had deteriorated in service; cop-led

bearing metal; roman metal; special steel, aluminum, and cast-iron
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 251

solder; lamp socket shells; aluminum casting alloy; monel metal

and B. & M. bronze, etc. Table of Test Items.—A list of the total number of tests made for

Government departments, the Bureau and outside concerns is given

in the accompanying table. The total estimated value of all tests made for the past year is $13,100.

Heat treatment and thermal

analysis.

Metallographic f including physical, chemical, and corrosion)

tests. Fusible plugs. Total.

Irons and

steels.

Nonferrous metals.Irons and

steels.

Alumi- num

alloys.

Brass and

bronze.

Miscelcella- neous.

FOR THE GOVERNMENT.

Bureau of Standards 834 400 58. 12I1,293

2

1116 655

3946

1 48

1 25

1 38

"E-mpTPpnnv Flppt Cornoration . . Navy Department 3

12 6 Panama Canal

655 War Department 311 76 56

1 1 Treasury Department

Post Office Department 1 Coast and Geodetic Survey 48 Bureau of Engineering 1 National Advisory Committee 25 Bureau of Engraving and Printing 1 TJ. S. Railroad Administration 38

Total 1,146

2 549 124

11

72 I1

1 655 2,491 EOR THE PUBLIC 22 Grand total 1,148 549 135 9 15 2 655 2,513

Circulars of Information.

There is now going through the press a circular of information on

nickel in which has been assembled all the available information as

to the manufacture and properties of nickel and of its most important alloys. This forms one of a series of which copper and aluminum have previously appeared. There has also been issued a circular letter on high-speed steel, giving information as to its composition and physical characteristics and performance for various grades

of this material.

Cooperation with Technical and Scientific Organizations.

The members of the metallurgical division have maintained active

relationship in the work of several national scientific and technical

organizations, including the National Advisory Committee for Aeronautics; the National Research Council; the American Institute of

Mining and Metallurgical Engineers, which held a highly successful

symposium on pyrometry October last; the American Society for

Testing Materials; the American Physical Society, Engineering

Standards Committee; Society of Automotive Engineers; and the

Reclassification Commission.

Ordnance Detail and Visitors.

During the past year several men (from three to four) from the

Ordnance technical staff have been constantly at work in section 1 of this division. These men have been working upon problems as-
252 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

signed to them by the technical staff, while the Bureau has furnished

most of the facilities for carrying out the work, although the

ordinary supplies and some of the apparatus were furnished by

the Ordnance Department. The following problems may be listed as typical of these investigations : Determination of the hardness of

cartridge brass shells by means of the micro-Brinell testing set; the

study of fractures of gun steel and its correlation with the structure of such steel; the structure and treatment of steel cores for armorpiercing bullets; the structural changes produced by ammonia in

steel. During the year a representative of a large machine shop has spent some time at the Bureau working upon the problem of the conditions affecting the hardness of carbon steels. Upon the request of the Spanish Embassy, the Bureau granted

permission to Dr. Emilio Jimeno-Gill, professor of chemistry of the

University of Oviedo, to undertake research work on the problem

of " The relation of grain size of carbon steel to mechanical hardness."

Air. Yamanchi, representing the South Manchurian Railway, applied through the Japanese Embassy for permission to study along

the line of metallurgy at the Bureau. The request was granted and

Mr. Yamanchi assisted in carrying out the work on the problem of

the mechanical properties of a high chromium steel under varying

thermal treatments. Mr. Franklin K. Bell obtained permission through Dr. Owens, of

Johns Hopkins University, to use the facilities of the Bureau and

made up a rather complete series of the iron-copper alloys.

Travel.

During the year a three-months' trip abroad was taken by a member of the staff for the purpose of obtaining information on the subject of suitable and proper limits for sulphur and phosphorus in

iron and steel. Both France and England were visited, the greater

part of the time being spent in England. The effort was made to get

in touch with the users of steel products—particularly railway materials as well as manufacturing and scientific metallurgists. Advantage was taken of the opportunity to visit scientific laboratories,

particularly those engaged in the study of metals.

Members of the division were given the opportunity to attend conferences and meetings on scientific and technical subjects.

Typical Micrographs on Exhibit.

Micrographs in the form of large transparencies, typical of the

various metals and alloys, have been prepared as a permanent exhibit

in the metallographic laboratory.

Correspondence.

The metallurgical division carries on an extensive correspondence on metals and a typical list of the most interesting items is that

given for the month of October, 1919, as follows : Tests on electric

steels; alloys suitable for duplication of patterns; properties of a new ferrous alloy; alloys suitable for use in fusible plugs; use of

pure zinc in galvanizing; improvement of metallographic micro-
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 253

scopes ; aluminum castings ; testing of alloys ; effect of phosphorous on steel castings; problems in chain manufacture at Boston Navy

Yard ; preparation of standard steel samples ; rebabbitting shaft

boxes ; malleable iron industry ; tempering of copper ; British NonFerrous Research Association to National Eesearch Council; new

processes for making aluminum solder ; hardness of nickel and

nickel-chromium steel ; research in a possible new aluminum alloy

;

qualities of electric steel; performance of Ajax induction furnace;

information relating to zirconium and zirconia ; furnishing pure

iron; preparation of manganese and other ferrous alloys; pure

manganese; transformations in alloy steels; procuring and testing car wheels : annealing of car wheels ; automobile babbitt metal

;

detecting gold in the ground ; flux for soldering brass ; solder of intermediate melting point ; stainless steel ; bario metal ; light aluminum

alloys; testing of foundry clays; books on forging; apparatus for

transformation point determinations; cooperation with rolling mill

research; boiler plate investigation; metallurgical problems suitable

for doctor's dissertation; zirconium steel research; submarine periscopes ; investigation of alloy " trialoyium " ; specification for pressure

reducing valves ; determination of hydrogen in steel ; expansion of

brass in rifle shells ; heat treatment of duralumin ; Shimer case hardening process ; heat treatment of galvanometer pivots ; sulphur and

phosphorus contents in steel ; bronze castings ; manufacture of monel

metal ; high melting point alloys ; data on' production of metals

;

absorption of gases by iron and steel; comments on aircraft metals

specifications and on ordnance metals specifications.

Conferences.

On May 17 there was held at the Bureau a conference between

representatives and an advisory committee of the American Foundrymen's Association. There were discussed several research problems

of interest to foundrymen, which it was desired to have the Bureau

continue work upon, such as molding sand standards, the determination of the thermal conductivity of sand molds, mold finishings, sand

casting and the cleaning of castings, and shrinkage values and characteristics for various types of casting, a determination of oxygen in

cast iron, and the metallography of inclusions in cast iron.

On June 17, 1920, representatives of the steel car wheel manufacturers and one large railroad system met at the Bureau, where a demonstration was made of the Bureau's apparatus for testing thermal stresses in chilled iron car wheels, and a tentative program was

formulated for tests of steel car wheels, which are to be furnished by

all the large manufacturers. Both new and used rolled and cast

steel wheels are to be tested. Two meetings have been held, at the Bureau of the nonferrous

alloys committee for the purpose of advising with the Bureau on its experimental program and in outlining investigations on such alloys.

Among the items of research urged upon the Bureau were the fol- lowing: (1) Corrosion, (2) bearing metals, (3) characteristics and

properties of cores and core oils. These meetings are of particular

value to the staff of the Bureau, as they offer the opportunity for an

interchange of experience on subjects relating to metallurgical re- search of particular interest to the nonferrous metal industry.
254 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

A conference on copper crusher cylinders was held at the Bureau

on September 8, at which representatives of the War Department

(Ordnance and Arsenals), powder manufacturers, and the Bureau

were present. A set of specifications for copper cylinders and instructions were tentatively adopted.

Several conferences were held during the year, resulting in the

formation of a joint committee on investigation of sulphur and phosphorus in steel. This committee, having to do with the question of enormous economic importance not only to one of our largest basic

industries and to all consumers of steel but to all the community, was

finally organized on June 23, 1919, with the following cooperating

bodies : United States Bureau of Standards, chairman ; United States Railroad Administration (replaced by the American Railway Association) ; War Department; Navy Department; American Society

for Testing Materials ; Society of Automotive Engineers ; Society of

Naval Architects, Marine Engineers; National Research Council;

Association of American Steel Manufacturers ; Steel Founders Association of America; American Foundrymen's Association. A sys- tematic program of investigation has been laid out and excellent

progress made in the execution of the investigation.

Publications.

The following publications have appeared during the past year

:

Report of the Pyrometer Committee of the National Research Council, G. K.

Burgess, A. I. M. M. E., Sept., 1919. Metals for Pyrometer Standardization. C. W. Waidner and G. K. Burgess,

Bull. A. I. M. M. E. (Aug., 1919). No. 152, p. 1511. Metallographic Features Revealed by the Deep Etching of Iron and Steel, H. S. Rawdon and Samuel Epstein, Tech. Paper 156. Nature of the Defects Revealed by the Deep Etching of Transversely Fis- sured Rails, H. S. Rawdon, Report 85 to Rail. Com. Am. Ry. Assn., Nov., 1919, and Chem. and Met. Eng., 22, p. 505. A Study of the Deterioration of Nickel Spark Plus; Electrodes in Service, H. S. Rawdon and A. I. Krynitsky, Tech. Paper No. 143, A. I. M. M. E. Bull., 152 (1919), p. 1323. Microstructure of Iron and Mild Steel at High Temperature, H. S. Rawdon

and H. Scott, Sci. Paper No. 356, Min. and Met. (Feb., 1920), No. 158, Sec. 18. Chem. and Met. Eng., 22 (1920), p. 787. A Peculiar Type of Intercrystalline Brittleness of Copper, H. S. Rawdon

and S. C. Langdon, Tech. Paper No. 158, Min. and Met. (Feb.. 1920) Bull., 158, Sec. 19. Intercrystalline Brittleness of Lead, H. S. Rawdon, Sci. Paper No. 377, Min. and Met. (Feb., 1920) Bull., 158, Sec 7. Applications of Metal Radiography, H. S. Rawdon, Proc. A. I. and S. Inst., 1919 (October meeting).

Contemporary Foreign Opinions on Sulphur and Phosphorus in Steels, H. S. Rawdon, Chem. and Met. Eng., 22 (3920), pp. 609-612. Contribution to Discussion of " Shattered Zones in Certain Steel Rails," H. S. Rawdon, A. S. T. M. Proc, 1920 (June).

Manufacture and Properties of Light Wall Structural Tubing, H. J. French, BuH. A. I. M. M. E. (Sept., 1919), No. 153, p. 1855. Tensile Properties of Boiler Plate at Elevated Temperatures, H. J. French,

Min. and Met. (Feb., 1920), No. 158, Sec. 15. The Heat Treatment of a High Chromium Steel, H. J. French. Jour. S. A. E., July, 1920, vol. 7, No. 1, p. 103 ; Chem. and Met. Eng., July, 1920, vol. 23, No. 1, p. 13. Some Applications of Alloy Steels in the Automotive Industry, H. J. French,

Paper, A. S. M. E., Wash. Sec, March SO, 1920. Use of a Modified Rosenhain Furnace for Thermal Analysis, H. Scott and

J. R. Freeman, Sci. Paper No. 348, Bull. A. I. M. M. E. (Aug., 1919), No. 152,

p. 1429.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 255

The Heat Treatment of Duralumin, P. D. Merica, R. G. Waltenberg, and

H. Scott, Sci. Paper No. 347, Bull. A. I. M. M. E., June, 1919, No. 150, p. 913. Critical Ranses of Some Commercial Nickel Steels, H. Scott, Sci. Paper No.

376, kin. and Met. (Feb., 1920), No. 158, Sec. 16. Similarity of the Magnetic Change in Ferrite and Cementite, Scott and

Movius, Chem. and Met. Eng. (June, 1920), 22, No. 23, p. 1069. Discussion of Stresses Set Up by Cold Rolling, R. W. Woodward, Proc.

A. S. T. M., 1920. Equilibrium Conditions in the System, Carbon, Iron Oxide, and Hydrogen

in Relation to the Ledebur Method for Determining Qxygen in Steel, Sci. Paper No. 350, J. R. Cain and Leon Adler. Oxygen Content by the Ledebur Method of Acid Bessemer Steels Deoxidized

in Various 'Ways, J. R. Cain and Earl Pettijohn, Sci. Paper No. 346. Electrolytic Resistance Method for Determining Carbon in Steel, T. R. Cain and L. C. Maxwell, Tech. Paper No. 141, Jour. Ind. and Eng. Chem..

vol. 11, No. 9, p. 852, Sept., 1919. Determining Gases in Steel and the Deoxidization of Steel, J. R. Cain.

A. I. M. M. E. Bull. (Aug., 1919), No. 152. p. 1309. Preparation and Reflective Properties of Some Alloys of Aluminum with

Magnesium and Zinc, R. G. Waltenberg and W. W. Coblentz, Sci. Paper

No. 363. Physical Properties of Certain Lead-Zinc Bronzes. H. F. Staley and C. P. Karr, Bull. A. I. M. M. E. (Sept., 1919), No. 153, p. 24851 Some Tests of Light Aluminum Casting Alloys—The Effect of Heat Treat- ment, P. D. Merica and C. P. Karr, Tech. Paper No. 139, A. S. T. M. (1919),

vol. 19. Pt. II, p. 298. A Simplification of the Inverse-Rate Method for Thermal Analvsis, P. D. Merica, Sci. Paper No. 336, Bull. A. I. M. M. E. (July, 1919), No. 151," p. 1021. The embrittling Effects of Cleaning and Pickling Upon Carbon Steels, S. C. Langdon and M. A. Grossman, Electrochem. Soc, 1920 (April).

Tin Fusible Boiler-Plug Manufacture and Testing, L. J. Gurevich and J. S. Hromatko, Bull. A. I. M. M. E. (Aug., 1919), No. 152, p. 1351. Graphitization of White Cast Iron upon Annealing, P. D. Merica, L. J. Gurevich, Tech. Paper No. 129, Bull. A. I. M. M. E. (July, 1919), No. 151, p. 1063. Tests of Clay for Foundry Uses, H. F. Staley, Trans. Amer. Foundrymen's

Assn. (1919), vol. 2S, p. 465. Cements for Spark Plug Electrodes, H. F. Staley, Tech. Paper No. 155. Stresses Caused by Cold Rolling, H. M. Howe and E. C. Groesbeck, Tech. Paper No. 163, A. S. T. M. (June, 1920).

Temperature Measurements in Steel Furnaces, G. K. Burgess, Amer. I. and S. Inst. (Oct., 1919).

Characteristics, Uses, and Treatment of High-Speed Tool Steels, Scott, Letter-circular VIII-7. The following publications are in preparation or in press

:

Steel Rails from Ordinary and Sink-Head Ingots, G. K. Burgess, Bureau of Standards Tech. Paper.

Governmental Research, G. K. Burgess, Royal Canadian Institute. Investigation of New Deoxidizers for Steel Manufacture. Report of Committee 14 of Engineering Division of National Research Council, by J. R. Cain. Thermal and Physical Changes Accompanying the Heating of Hardened Car- bon Steels, H. Scott and H. G. Movius, A. I. M. M. E. Relation of the High Temperature Treatment of High Speed Steel to Sec- ondai'y Hardening and Red Hardness, H. Scott, Bureau of Standards Scientific Paper. Cast Iron for Locomotive Cylinder Parts, Bureau of Standards Tech. Paper.

C. H. Strand. Note on the Properties of Antimonial Lead, J. S. Hromatko and L. J. Gurevich. Study of the Relation Between Brinell Hardness and Grain-Size of Annealed

Carbon Steels, H. S. Rawdon and Emilio Jimeno, B. S. Sci. Paper —

.

Electric-Arc Welding of Steel—The Properties of the Arc-Fused Metal, H. S. Rawdon, E. C. Groesbeck, and L. Jordan, B. S. Tech. Paper. Also presented

before the Washington Sec. of A. S. M. E.
256 REPORT OF DIRECTOR OE BUREAU OF STANDARDS.

Metallographic Etching Reagents for Copper, H. S. Rawdon and M. G. Lorentz, B. S. Sci. Paper —

.

Some Experiments on Copper Crusher Cylinders, A. I. Krynitsky, A. I. M.

M. E. Bearing Metals—Review of Literature and Some Miscellaneous Tests, R. W.

Woodward and J. R. Freeman, jr. Bearing Metals.—Elevated Temperature Tests and Properties of S. A. E.

Babbitts, R. W. Woodward, and J. R. Freeman, jr. Light Armor Plate with Special Reference to the Use of Zirconium, G. K. Burgess and R. W. Woodward.

Some Recent Foreign Alloys, R. W. Woodward.

Some Physical Changes in Iron and Steel Below the Thermal Transformation Range, H. J. French. Thermal Stresses in Chilled Iron Car Wheels, C. H. Strand. Erosion of Machine Gun Barrels, W. W. Sveshnikoff. Ternary Alloys of Tin, J. S. Hromatko.

Circular on Nickel, P. D. Merica. Discussion of Prof. Sauveur's paper on "Application of the Miscroscope in the Heat Treatment of Steel," G. K. Burgess, Amer. Iron and Steel Institute Proceedings, 1920. Discussion of Dr. Cushman's paper on " New Method for Testing Zinc Coatings," G. K. Burgess. A. S. T. M. Proa, June, 1920.

9. CERAMICS.

This division is concerned with the study of the principles involved in the production of the many kinds of clay products, such as the various structural materials, pottery, electrical porcelain and refractories, the manufacture of the different types of glass, including that used for optical purposes, and the enameling of metals. Owing to the fact that these industries are of basic importance in the development of the country and have not yet received systematic technical study the prosecution of researches tending to assist in the more rapid expansion of these industrial activities is of considerable importance.

CLAY PRODUCTS.

Use of American Clays in the White-Ware Industry.

The results obtained in the cooperative investigation conducted

with the United States Potters' Association have been published in

the Journa] of the American Ceramic Society, volume 3, No. 2, 1920.

It appears from the conclusions drawn that American kaolins are

suitable for the manufacture of Avhite-ware pottery, but that the

production of the primary kaolin needed is as yet not large enough

to satisfy the demand, and therefore the importation of English

kaolin must be continued until the resources of the country are fully

developed.

Paper Clays.

An extensive study has been undertaken of the properties of paper

clays, their fineness, plasticity, absorbing power, strength, and their

viscosity when treated with various sizing agents.

American Clays Suitable for the Manufacture of Graphite Crucibles

and Glass House Refractories.

A Technologic Paper, No. 144, has been published on this subject,

which gives the results of tests made upon a considerable number of

domestic clays. It has been shown that there are available many

American clays which are well adapted to these uses, and that it is not necessary to resort to imported materials.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 257

Clays from Palestine.

A series of clay samples collected in Palestine have been submitted

for tests for the purpose of determining their suitability for the

manufacture of structural materials needed in the reconstruction of

the country.

Study of the Drying of Clays.

The increased demand for more rapid manufacturing methods has

made it desirable to study the maximum speed with which different

clays may be dried, and also the relation between the rate of heating

and the contraction. It has been found that the more rapid the heating proceeds the smaller is the observed shrinkage.

Study of the " Water Smoking " of Clays.

The increasing use of the tunnel kiln makes it necessary to establish the maximum rate at which clays may be heated during the initial stage of the firing when the residual mechanical and hygroscopic

water is expelled. It has been found that clays may be heated much

faster than is generally supposed and that there are two critical temperatures, about 100° and 225° C, which must be considered during this process. The Effect of Aluminum Chloride Upon Clays.

It has been the practice in some porcelain works to acid small

amounts of aluminum chloride to the body mixture for the purpose

of improving its working quality. Tests, involving the addition of

aluminum chloride to kaolins and ball clays have been made and it was found that the reagent improved the strength of the kaolins in

the dry state, but not of the plastic clays. The addition of aluminum

chloride to porcelain compositions low in ball clay is therefore justified. Larger additions,- 0.1 per cent or more, seem to bring about an

undesirable condition in the plastic state, detrimental to satisfactory

molding.

Addition of Potassium Ferrocyanide to Clays.

The comparatively small amount of colloidal ferric oxide and hydroxide present in the plastic clays imparts to them a yellowish cast undersirable for paper-making purposes. It was thought desirable

to determine whether the color could be neutralized by the addition

of potassium or sodium ferrocyanide. It was found that this reagent

brought about an improvement in the color and this method might

hence be emploj'ed for treating certain kaolins.

Function of Caustic Soda Added to Clays.

In the "purification of clays through deflocculation by means of

caustic soda the function of the reagents and especially the degree of

its absorption by clay has not been known. The amount of alkali

absorbed by the ckvy was therefore determined for several kaolins

and found to be practically constant. Tests of Feldspar and Flint. Considerable variation exists as to the fineness of the commercial

grades of flint and feldspar offered on the market and also with refer- 10613—20 17
258 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

ence to the fusibility'- and color of the feldspar. Tests have been made

of a large number of commercial samples and the results may be

used as a basis for specifications for materials so essential to the pottery industry.

Effect of Ground Quartz Upon Plastic Clays.

The use of ground quartz (potter's flint) is more or less common in

diverse ceramic industries and more definite knowledge concerning

its effect upon the drying and burning, shrinkage and porosity after

firing is essential for the intelligent use of this constituent. The

properties mentioned were determined for three typical ball clays

with additions of ground quartz varying from to 50 per cent. The

rate of decrease in shrinkage and increase in porosity with increasing

proportions of flint was thus established.

Mechanical Strength of Typical Clays.

No systematic information concerning the strength of the different types of clay used in the fabrication of the cruder structural

materials is available. This situation made it necessary to conduct

tests upon a number of typical shales and clays consisting in firing

bars made from them to a series of temperatures and determining

the transverse strength for the different stages of burning. The

graphical presentation of the results is of interest in showing the

increase in strength with increased heat treatment and is useful in

making possible specifications for the testing of clays. The transverse strength was used as a criterion due to the fact that in use

structural products are usually subjected to stresses of this kind and

not to pure compression or tension.

Properties of Fire Brick.

Technologic Paper No. 159, published during this year, gives

the results of tests of fire bricks with reference to their fusibility,

resistance to load, contraction in volume, and decrease in porosity.

About 60 well-known brands of fire brick have been studied and the

results are of value to users of clay refractories.

Transverse Strength of Fire Clay Tiles at 1,350° C. Owing to the dearth of information concerning the effective

strength of fire-clay tiles used so largely in furnace and coke-oven

construction an investigation has been begun for the purpose of

computing the modulus of rupture and the deformation of standard

refractory tiles for different spans. Structural Terra Cotta. In cooperation with the National Terra Cotta Society a large

number of terra cotta mixtures have been tested for contraction,

porosity, and transverse strength when fired to seven temperatures.

In addition the resistance to disintegration of these bodies after

repeated immersion in a sodium sulphate solution and subsequent

drying was observed. From a study of the results tentative specifications for terra cotta have been proposed, subject to revision after

additional work has been done.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 259

A study of the thermal coefficient of expansion of the terra cotta bodies of the country is now under way and an elaborate program

has been arranged for additional tests. Refractories for the Glass Industry.

An investigation is under way and partially completed dealing

with the resistance to glass corrosion of various combinations of

American clays, involving the use of silicious and aluminous bond

•clays and of calcines made from the same materials. It has been

found that silicious clays as a class resist corrosion better than

aluminous materials, but that clays very high in silica are less re- sistant than those moderately silicious. A combination of clays

high in silica with more aluminous ones is therefore most desirable.

Dense bodies are more resistant to corrosive action than more porous

ones, but there seems to be a certain degree of tolerance with ref- erence to the porosity of silicious cla3's which is absent in the materials lower in silica. It also appears that the size of the pores

is of considerable importance as regards the capillary flow of glass

into the structure of the body, a point which requires still further

study.

Porcelain.

A study of high fire porcelains has suffered some interruption

OAving to the transfer of the work from the Pittsburgh branch to the

Washington laboratory but has been taken up again vigorously. A

series of porcelains containing zirconia and thoria have been made

which possess desirable properties particularly excellent resistance to sudden heating and cooling. They are, however, not refractory

since even with contents of these oxides up to 50 per cent and with

feldspar as low as 8 per cent vitirification took place at temperatures

below 1,400° C. An extensive study is being made of hard fire porcelain glazes,

which will supply complete and reliable data concerning the glazes

to be employed for the different firing temperatures.

Solubility of Fritts. A study has been made of the solubility in water of the so-called

" fritts " employed in the preparation of glazes for the white-ware

pottery industry. The ,l fritts " are glasses high in boric oxide pre- pared for the purpose of rendering the boric acid and borax used

insoluble, since otherwise a large portion of these constituents would

be removed by the water used in grinding. It was found that the

thoroughly fused fritts were quite insoluble but that those which

were poorly mixed and melted were decidedly soluble. It appears

from the results obtained that the use of special melting furnaces

for the preparation of the fritt is strongly advisable.

The Effect of Molding Structure Upon the Rate of Vitrification of

Porcelains.

Porcelain specimens were made from the same composition but

molded by pressing in the plastic state, by casting and by pressing

as moist dust under three pressures, 2,000, 4,000, and 6,000 pounds

per square inch. Upon firing these specimens in the same kiln under
260 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

identical conditions it was found that the dust pressed specimens

showed a much slower rate of vitrification than the plastic pressed

and cast pieces, but that this rate increased with increase in pressure. Dust pressed porcelains by applying a sufficiently high pressure may

therefore be caused to vitrify ait a rate approaching that of plastic

molded bodies.

Equipment.

The equipment of the new ceramic laboratories at Washington has

been completely installed and provision has been made for precision measurements upon the physical properties of clays and ceramic

products. The kiln and furnace equipment is very extensive and has

been operated sufficient^ long to insure its proper functioning. The

installation for the making of heavy cast ware is ready for operation. ENAMELED METALS.

Fish Scaling in Enamels for Sheet Steel. The jumping off of small particles of enamel Avhich results in the

defect known in shop practice as " fish scaling " is probably the most

serious defect to which enamels for sheet steel are subjected. It occurs intermittently in practically all the plants manufacturing this

class of material in this country and entails losses running into

millions of dollars to the manufacturers. At the request of the Metal- ware Manufacturers Association of America, the Enameled Metal

Division of the American Ceramic Society, and of a large number of

individual manufacturers, the Bureau is carrying on a comprehensive

research in art endeavor to discover the cause or causes of this defect

and the methods of controlling and eliminating it. This investigation was begun in July, 1919, and has been conducted energetically ever since. Up to the present time, the investigation has been confined

to one-coat gray enamels. The Bureau has made 90 melts of enamel

comprised of 21 different compositions. These have been subjected

to various treatments in firing and melting and have been applied in

various wa3's to several kinds of steel. In all, over 4,000 sample

enameled plates have been made. The work clone up to the present

time indicates that the primary cause of fish scaling in enamels is higher coefficient of thermal expansion of steel than of the enamels

used for coating the steel. Any circumstance which interferes with

proper adhesion of the enamel to the steel increases the tendency to

fish scaling. Among these may be mentioned the formation of oxide,

grease, or other form of dirt on the steel. In one-coat gray enamels,

overfiring has a decided tendency to produce fish scaling.

The data obtained in this investigation up to the present time have

enabled the Bureau to be of very material assistance to several manufacturers in eliminating this trouble. It seems very probable that

the completion of the investigation as now planned will definitely

eliminate fish scaling, and likewise settle the interesting question of

what is the physical basis of the phenomenon.

The Relation of Composition of Enamel to Solubility in Acids.

For several months the Bureau has had in progress an investigation

of the relation of composition of enamel to solubility in strong mineral
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 261

acids. The need for this investigation was clearly demonstrated

during the war by the difficulty manufacturers of acid-resisting

enameled wares experienced in meeting the requirements of chemical

manufacturing plants. The manufacturers of enameled kitchen wares are also interested in this problem. Up to the present time.

72 enamel compositions have been melted and tested. While the

problem is a large one and the investigational work will necessarily

be continued for some time, results so far obtained indicate that some

of the commonly accepted conceptions of the relation between composition and acid resistance of enamels are erroneous. The chief of

these misconceptions seems to be that oxides which are similar in

nature chemically will have similar effects when incorporated in

enamel compositions. That this is not always true is shown by the

fact that calcium oxide tends to produce enamels with very low re- sistance to attack of acids while barium oxide produces quite resistant

enamels. In connection with the gathering of data on the chief

object of this investigation, information is being secured in regard to relations of composition to their fusibility and to the tendency to chip

or to craze or crack. As a matter of interest, it may be stated that as

a part of this investigation an enamel has been produced which ap- pears to duplicate in composition and working properties the best

grade of French acid-resisting enamel.

Study of Opacifying Agents in Enamels.

The Bureau has investigated about ten of the possible substitutes

for tin oxide for producing opacity in enamels. Of these it finds

that zinc spinel, zirconium dioxide, titanium dioxide, sodium antimonate. and oxide of antimony have promising possibilities as substitutes for tin oxide.

Substitutes for Antimony Oxide in Gray Coat Enamels. t In certain quarters there is objection to the more or less common

practice of using a small amount of antimony oxide in one coat enamels on utensils intended for culinary purposes. This objection

is based on the rather hypothetical assumption that such enamels

may be slightly poisonous. "While the Bureau believes this is not

the case, at the request of several manufacturers of this type of ware

it has undertaken the investigation of possible substitutes for antimony oxides for making such enamels. It has been found that zinc

oxide, tin oxide, and zirconium oxide can be used in place of antimony oxide.

Miscellaneous Investigations in Enamels.

The Bureau has conducted A'arious metal investigations in relation

to the enameling industry, among which may be mentioned : Methods

of cleaning metals for enameling: production of enamels for watch

dials ; the study of the technique and compositions to be used in

enameling silver: the compositions used for enameling cast iron by

the dry process and the compositions and technique of enameling

sheet steel and cast iron by the wet process.
262 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

REFRACTORIES.

Refractory Crucibles.

The division has investigated the making of crucibles from highly

refractory oxides and minerals. It has found it possible to make

such crucibles without the use of clay or other binder which would

tend to reduce the refractoriness of the crucible. One method is to make the crucible with the use of water by tamping the plastic mass

inside of a fire-clay mold lined with plaster of Paris. When the mold

and crucible are fired to a red heat the plaster of Paris disintegrates

and permits the crucible, which is then fairly strong, to be removed

from the mold. The crucible is then fired to a high temperature in

order to render it sufficiently dense and strong. The other method

consists of mixing linseed oil with refractory oxides and shaping

the crucible inside of a detachable metal shell. The crucible is then

baked in the shell in a core oven in the same way that cores for

casting are baked. The shell is then removed and the crucible fired to a high temperature. This firing results in a burning out of the

temporary carbonaceous binder and a sintering of the refractory

oxides so as to form a dense, strong, and highly refractory crucible.

Working in this way crucibles have been produced from titanium

dioxide, zirconium dioxide, and carborundum fire sand. This in- vestigation is being continued.

The Heat Conductivity of Metallurgical Refractories.

The refractories section of the division, in cooperation with the

heat division ox the Bureau, has been conducting an investigation on the heat conductivity of the refractory materials used in metallurgical furnaces. The necessity for this investigation arises from

the fact that very little is known quantitatively in regard to the

heat conductivity of these materials. The whole question of eco- nomic construction and operation of metallurgical furnaces and the

possibility of the development of a number of new types of metallurgical furnaces, particularly of electric furnaces, is dependent

largely on the extension of our knowledge of the heat conductivity of

metallurgical refractories. It is proposed to determine not only the

heat conductivity of individual brick made from various refractories,

but also of furnace walls made from such brick. To conduct this

investigation it has been necessary to develop new types of apparatus and methods of heat measurements. This preliminary work

is about completed, and it is hoped that in the near future we will

be able to make actual measurements. As a part of this investigation,

apparatus and methods that can be used for measuring the heat

conductivity of the walls of furnaces in actual operation in metallurgical plants are being developed.

Cooperation with Technical Organizations.

The division has cooperated with many technical organizations,

among which may be named the American Ceramic Society, the

American Society for Testing Materials, the National Brick Manufacturers' Association, the National Terra Cotta Society, the Sheet

Metal Ware Manufacturers' Association, the United States Potters' Association, etc.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 263

Cooperation with Governmental Departments.

Cooperation has been maintained with a number of departments,

both as regards information on ceramics, routine tests, and the supply

of material. Among these may be mentioned the Navy, the United

States Geological Survey, the Panama Canal, the Tariff Commission, the Bureau of Mines, the Washington Navy Yard, the Department of Agriculture, and others. In addition, the division kept in

close touch with the activities of the National Research Council.

Assistance Rendered Individual Manufacturers.

The division was visited by many individuals and representatives

of corporations with reference to specific problems and the corre- spondence relating to this work is becoming increasingly voluminous.

GLASS.

Equipment.

The glass plant at the Washington laboratory has been fully

equipped and is now in operation. The furnace equipment is complete and permits of the making of all kinds of glass from the differ- ent commercial kinds to the highest type of optical glass. The molding apparatus is adequate for conducting all the operations neces- sary, and skilled glassworkers are available for doing this work

properly. Ample provisions have been made for the inspection of

optical glass through cooperation with the division on optics and

the glass-grinding laboratory of the Bureau.

Colored Glasses.

A large amount of work has been done on colored glasses for a considerable variety of colors and the spectroscopic analysis of the

transmitted light. A number of special-colored glasses have been

prepared for the Navy and additional ones are being made. A study on the production of selenium red glasses has been published in the

Journal of the American Ceramic Society, volume 2. No. 11 (1919).

About 50 melts were made in monkey pots.

Optical Glass.

There were made 20 large melts of optical glass, including light

crown, medium flint, dense barium crown, light barium crown, and

baro-silicate crowns. The new regenerative furnaces have been

found to operate very satisfactorilv. There were molded from

November 1, 1919, to 'March 1. 1920, 100 six-inch disks. 500 lens

blanks, 2f inches in diameter, of medium flint, and 2.500 blanks of

light barium crown. From March 1 to July 1, 1920. there were molded 10,665 lens blanks and slabs, weighing 7.468 pounds.

A large number of lens blanks thus produced were subjected to

precision annealing.

Inspection.

The equipment for handling and classifying the glass was greatly

improved and precision inspection made a matter of systematized

routine. A paper was published in the Transactions of the American Ceramic Society, volume 2, December, 1919, on the subject of

" Comparison Tests for Striae in Optical Glass/'
264 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Large Lens Blanks.

Pioneer work was done in connection with the molding of large

lens blanks, weighing from 38 to 365 pounds, employing clay forms

heated in a muffle furnace. This work is being continued and it has been demonstrated that the method employed is satisfactory.

Miscellaneous Work.

A considerable number of inquiries concerning problems in glass

technology hare been received and answered as fully as possible.

In some cases experimental work was necessary in order that the

questions might be answered correctly.

Small tubing, one-sixteenth to one half inch, was made up from

about 250 pounds of glass for the chemical division of the Bureau.

A considerable number of prism blanks, disks, cylinders, and sheets

of optical glass have been made for the use of different divisions.
III. THE OFFICE.

The work of the office includes the general supervision of the clerical work of the Bureau,

office management for the central office, including funds and accounts, tests, information, appointxent and other matters connected with personnel, the central editing of technical

ma.-.i; scripts, property and stores, mail and files, technical library, dispatch, including all forTMs of transportation and communication, purchasing, and stenography, typewriting, and

duplicating. During the year special attention Avas given to perfecting the

organization on a peace basis so that essential routine could be car- ried with a minimum of clerks. The Avork of the office is in general

in better condition than at any previous time in the history of the

Bureau, considering the limited force available.

The matter of office space is most serious. In some offices the

space per person is less than the minimum standards recognized for

office work. In view of the urgent need for laboratory space and the

suitability of the south building for that purpose, it is hoped that

initial steps may be taken during the year toward the planning of an administration building to house the administrative offices of

the Director, the general offices, the library, and the necessary technical conference room, etc. ACCOUNTS.

Funds and Disbursements.

The regular appropriations of the Bureau amounted to $1,397,260.

Additional items, amounting to $495,000, were carried in the first deficiency appropriation act, making a net total of $1,892,260. Beimbursements were received from other departments for certain co- operative researches, although not in the same volume as during the war. The total expenditures during the year amounted to $1,686,- 345.56. During the current year Congress authorized special transfers of funds from other departments desiring cooperative research

for which the Bureau's direct funds are inadequate effective July 1, 1920.

Staff. The accounting staff was reduced during the year. The loss of four

of the senior clerks was a serious handicap, but their successors have

done excellent work in the emergency. The test record work and the

clerks engaged in test records were transferred to the finance section

and the procedure somewhat reorganized. Barts of the work necessarily minimized during the Avar Avere brought up to date with the

assistance of temporary clerical help. The test work is hoav proceeding normally.

Appropriation Statements.

The folloAving statement sIioavs the amount and object of each

appropriation provided for the Bureau for the fiscal year 1920, the dis- bursement during the year, the amount of unpaid orders at the close

265
266 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

of the year, and the unexpended balance remaining at the close of

business June 30, 1920:

Appropriation.

Salaries Equipment

General expenses Grounds

Testing structural materials Testing machines

Metilturjicalresearch : Investigation of optical glass Standard materials In est'g tion of textiles, etc Sugar st mdarduation Gouge standardisation High temperature investigation Testing nilroad snles, etc In .'estimation of fire-resisting properties In T estig5tion of railway mstenals

Testing mis lellaneous materials

Public-utility standards Rodio research In iust'dal research, 1920 Sound investigation In 'estigation of clay products C olor st m iardiz°tion Physical c onst ints Standardising meohanical appliances. .

.

Investigation of mine scales and cars..

.

In lustrial safety st mdards

Testing Government miteriils

St in iordizotion of equipment

Plstinum and rare met lis Ret lining wall In iustrial research, 1919-20 Equipping laboratory, 1919-20

Total

Amoi lnt appropriated.

.L/l . 1 HJ1 BC- menfs. Liability. Balance.

!|54J5r>, oo $443, 621. 86 819,990. 05 823,148.09

' 108, 033. 00 77, 873. 51 29,655.57 50.3. 92

95, 000. 00 28, 354. 07 56, 689. 45 9,956.48

7, 500. 00 6,

6

n

6. 18 8 '8. 02 45.80

2 150, 283. 29 122, 879. 59 27, 175. 78 227.92

3 35, 263. 49 29, 804. 88 5, 452. 76 5.85

4 30, 010. 63 26,02,2. 74 3, 875. 00 142. 89

5 63,995.34 55,027. 79 8, 8^2. 44 145. 11

5, 000. 00 3,577.22 1, 403. 84 18.94

15, 000. 00 14, 609. 96 378. 39 11.65

6 21, 800. 00 17, 069. 37 4,536.72 193.91

7 56, 276- 90 50, 675. 87 5, 304. 93 296. 10

X0, 000. 00 7,206 39 2, 762. 71 30. 90

8 43, 514. 40 34,605. 88 8, 162. 43 746.09

25,000. 00 21, 38'. 92 3,559.43 57.65

15, 000. 00 13, 636 59 1 , 337. 42 25.99

30, 000. 00 27, 377. 57 2,521. 25 101. 18

9 114, 159. 82 107, 089. 84 6,954.73 115. 25

10 31, 555. 91 30,231. 34 1, 287.29 37.31

11 290, 98?. 39 187, 834. 20 101,9)6. 12 1,202.07

12 7, 237.04 5,378.20 1,760.86 97.98

20, 000. 00 18, 106. 19 1,858. 15 35.66

10, 000. 00 8,961.10 999.21 39.69

5, 000. 00 4, 8"9.00 167. 00 4.00

11,11 Kn Qin <~/R ou, ozU. 36, 259. 71 14, .50/. yi 202. 64 « 15, 179. 73 14,722.48 403. 77 53.48

25,000.00 19,305.84 5,406.50 2S7.66

100, 000. 00 60,506.51 19,357.37 20, 136.12 " 52, 292. 00 19,335.30 14,701.63 18, 255. 07

15, 000. 00 13,385.91 1,598. 74 15.35

20, 000. 00 15,854.97 4,116.29 18. 74

'« 71,899.23 J71,631.42 1.70 266.11

100, 000. 00 92,551.16 6,827.10 621. 74

2,127,593.46 1,6S6,345.56 364, 200. 56 77,047.34

1 Includes reimbursement of $33 from other departments.

2 Includes reimbursement of $25,283.29 from other departments.

3 Includes reimbursement of $5,263.49 from other departments.

4 Includes reimbursement of $5,040.63 from other departments.

5 Includes reimbursement of $13,995.34 from other departments.

6 Includes reimbursement of $1,800 from other departments.

7 Includes reimbursement of $16,276.90 from other departments.

8 Includes reimbursement of $3,514.40 from other departments.

9 fnoludes reimbursement of $29,159.82 from other departments.

10 Includes reimbursement of $1,555.94 from other deportments.

11 Imludes reimbursement of $10,982.39 from other departments.

12 Includes reimbursement of $2,237.04 from other departments.

13 Includes reimbursement of $35,820.26 from other departments. H fn 1 hides reimbursement of $179.73 from other departments.

13 Cn3lu des reimbursement of $2,292 fr om other dep irtments.

10 Includes reimbursement of $21,833.23 from other deportments. The following statement shows the condition of the appropriation

for the two preceding fiscal years at the close of business June 30,

1920:

Appropriation.

FISCAL YEAR 1918. Salaries Equipment

Geue'al e xpenses Repairs and alte ations Grounds

High-potential in . estigation Testing structural materials Testing machines

In .-estigation of fire-resisting properties.

Public-utility standards

In vestigation of railway materials

Amount

appropriated.

$348, 900. 00 55,000 00

3 ),000. 00

5, 000. 00

6, 000. 00

15,000. 00

i 210,514.00

30, 030. 00 21,000.00

50, 003. 00

15,000. 00

Bisburseruents.

Liability. Balance.

$316,619.03

54,00!.S9

34, 003. 64

4, 945. 18

5, 946. 40

14,.r 3s.2L 186,452.92

29, 543. 64

2i,8Sl. 19

49, 9"2. 91

14, 60S. 99

$32,2^0. 97

189. OS

640. 28 8.82

53. 60

163. 85

9, 640. 27

418. 17 US. 81 .36

362. 51

$809. 03

3-.0. 0? 46.00

237. 94 14,420 81

38. 19

46.73 2S.50

1 Includes reimbursement for $60,514.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 267

Appropriation

.

Amount

appropriated. disburse- ments.

L/lu oiuiy

.

balance.

fiscal year 1918—continued.

Testing miscellaneous materials $20, 000 00 $19,9

_3.2S T26.55 $20 17 Radio research 10,000 0!) 9,969.24 30 76 Color standardisation 10,000 00 9,666.58 126. 90 206. 52 Investigation of clay products 10,000 00 9, 994. 53 5.47 Physical constants 5, 000 00 4,994 31 5.69 Standardb.ine mechanical appliances : 10 000 00 9, 567. 18 432. 82

in' ono 00 9,910. 7« 65. 75 23.47

40^000 00 on 71 (Y3 Co, I La Uo 107. 27 Additional land 2"| 000 00 2', 000. 00

1 487,21=. 36 4fi7,902 3K 4,141.49 15,201.49 Gau?e standardisation, 1917-18 2 226, 9'2 47 223,935.10 2, 256. 67 780 70 Repairs, power plant ; 12,000 00 11,744.57 255. 43

National security and defense.

3 112,762 on 1 DS 9Q3 w 1 364 31 3 101. 14 New building 250, 000 00 249,947.53

' ' 52^47

"Mpf"-^l 1 nrnnpn 1 \iTArlr 100, 000 00 292 07 423. 11 Production of fabrics 35, 000 00 34,298.65 378. 75 322' 60

Industrial labo-atory S9.3, 500 00 8

Q3,840 80 9,186.97 472- 23

45, 000 00 31 , 514. 70 11, 559. 70 1,92 . ( 700 00 655. 20 10 90 33 90

Total 3,098,593 83 2,950, 685. 23 45, 554. 61 92,3"3.99

FISCAL YEAR 1919. Salaries 4. Z, .Shi 1 An00 374. 832. 59 1,168.03 56,359.38 Equipment 4 81.210 00 72,776.4? 7,002.02 821.50

£ 50, 100 76 45,796.2'! 4,220.58 * 83. 98 Grounds 7; 500 00 7,285.82 214.18 High-potential investigation 15] 000 00 14,619.24 209. 16 81.60 Testing structural materials 6 233 ' (=28 29 224^ ?42. 63 2, 422. 02 6, 863. 64

30' 000 00 29,200.58 739. 87 59. 55 Investigation of fire-resistins properties 2o'on 00 24.5P3.71 239. 73 196.56 Public utility standards. . . . . 7 55 '000 00 53,080.02 1,882.51 37.47 Investigation of railway materials 15' 000 00 14,858.64 12. 54 128.82 Testing miscellaneous materials 30] 000 00 29,672.99 122. 70 204. 31 Radio research 20' 000 00 19,838.41 161.59 Color standardization 10^000 00 9,786.45 172.98 49.57 Investigation of elav nroduels 20] 000 00 19, 76fi. I" 44. 68 189. 22

5,' 000 00 4,972.18 26. 99 .83 Standardizing mechanical appliances 10,1.00 00 9.8P1.79 14. 98 123.23 Investigation of optical glass "84,388 75 82,053.63 1,7,31.03 604. 09 Standard materials 4,000 00 3.833.24 96. 60 70. 16 Investigation of textiles, etc 10, 000 00 9,528. 41 360. 50 111.09 Sugar technology standards Gauge standardization

9 21 \ 350 00 20, 077. 31 1, 187. 23 85. 46

10 433 ' 000 00 422,7r3.48 7,369.88 2,923.64

20' 000 00 nor no

0, Wo, r? 10, 258. 2y 756. 03 Military research". 1918-19 1

1

ooo, 3y 1. 57 592, 979. 94 38, 506. 33 2,009.30 Investigation of mine scales, and cars. 1918-19 1'5, 000. 00 14,677.73 103. 23 219.01 Investigation of public-utility companies, 1918-19... 12 53' 522. 52 51,530.30 1,964. 71 27.51 Testing railroad scales, etc. « 4l] 104.' 70 39, 074. 89 752. 03 1,277.78

National security and defense.

Militarv researches 100, 000. 00 95,283.61 2,888.78 1,827. 61

40, 000. 00 on 1 7n q c 1U, /2c. 12 CiQ f\'i Thermite investigal ion 4,300. 00 3,906.84 344. 57 48. 59 Altitude laboratory 60,000. CO 59, 897. 19 102. 81 Power-plant equipment (industrial laboratory) 31,500. 00 31,461.01 38. 99 Completing laboratories * 235,000. (III 231,870. 41 1,631.24 1,498.35 Armament of fortifications, commerce transfer » 198,907. 20 139,510.77 6,883.01 52,513.42 Aviation, Navy, commerce transfer .- 5,000. 00 4, 998. 28 1.30 .42

Total 3,030,357. 7!) 2,796,806.40 103,775.07 129, 775. 72

1 Includes reimbursement of 8237,245.36 from other de wtments.

2 Includes reimbursement of 551.972.47 from other departments.

3 Includes reimbursement of $37,762 from other deia-tments.

4 Includes reimbursement of $200 from other departments.

5 Includes reimbursement of $100.76 from other departments.

6 Includes reimbursement of $108,628 29 from other departments.

7 Includes reimbursement of $5,000 from other departments.

* Includes reimbursement of $ 14,388.75 from other de lartments.

9 Includes reimb irsement of $1,350 from other departments.

10 Includes allotment of $233,010 from War Department.

11 Includes reimbursement of $233,435.57 from other departments.

12 Includes reimbursement of $3,522.52 from other departments.

13 Includes reimbursement of $1,104.70 from other departments.

14 Includes reimbursement of $18,907.20 from other departments.
'268 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Summary of Tests. The Bureau's work includes, among other things, a large amount

of testing standards, measuring instruments, and materials. Incident thereto, much of the testing involves primarily investigation

of the scientific principles underlying the tests, the studying of existing methods, and the development of new standard tests of

determinate accuracy. For each test a reasonable fee is charged, ex- cept when made for the National or State Governments. The number of tests completed during the year, together with their value, is shown in the following table

:

NuMBEK AND V.U.rK OK TESTS COMPLETED,1 FISCAL YEAR ENDING JUNE 30, 1920.

Nature of test.

Length: Tapes

Other length tests Mass:Weights

Srales and balances Capacity Hydrometry

Time

Fie -trical tests Photometry - Radioa'.'ti ity Temperature:

Clini 'ill thermometers

Other thermometers and mi -.ccl laneous Opti -al tc;ts: Sugar pola-imetry Other opti 'a! tests Chcmi 'al analyses: Stru ctural materials Other materials Standard simples

Mechanical instruments and appii ances Aeronautical instrument tests Physical tests of mated il ;: Cement

Other structural materials Miscellaneous mat? his, includ- ing paper, tex'ilcs, rubber

leather, etc Metallurgical tests Miscellaneous

Total

Tor Government.

Number, i Value.

207

1,806

1, Kit 1,032 742

145

5. 509 665

1.919

13

22, 848

3,031

1,522 2,030

1,798

'p.07

376

131

S.410

2,229

. 156 810

127

S174.70

1,881.65

510. 10 33.713 50 '617.75

153. ro

0,713 50 2,025.05

6, 595. 00 5.00

2.018.01

1,709.21

1,522.00

2,2t'0.00

17,698.50

11', 723. 00

1,177. 80

2,010.50

887. 50

00, 022. 50 5,030.10

2!, 129. 75

2.227. 00 1.152.50

72,398 | 295,051.25

For public.

Number. Value

94

1,191

3,057

3 5.581 377

103 1,102

1,221

3,322

11 11,91!

33

5, 037

2 125

35702

213

34,501

8217.45

1, 851. 18

1,333.50

0.00

3, 120 55

095. 25 142 00

2,890. 28

2

4 0. 50

6, 607. 10

147. 92

4,859.87

20. 25 4,182.35

107. 00

9, 747. 95

400 00

71.00

6. 00

005. 50

901.00

333. 75

700. (

Total.

Number. Value

39,450.30

301 2,997

4,221 1,035

6, 320

522

5, 558 1,232

2,022

1,115

21,019

0, 956

1,533

13,914

1,798

7 5 '8

5^ 644 V8

139

8,412

2,351

.513 '872 3:0

103, S99

8722. 15 3,733.13

1,849.00

33, 719. 50

4,921.33 0,875.50

0,672. 10

2, 195. 90

0,029.08

1,548,25

0, 442. 35

17,698.50

11 '.SCO 00

10, 925. 75

2, M0. 50

958. 50

66, 028. 50

5. 030. 00

25,330. 75

2. 5C0. 75 1,913.10

335,104.55

1 The tests reported in thi table include only the tests for which all technical procedure was entirely com netci during the year 1919-20.

- In addition the Bureau inspected 1,320,179 incandescent lamps at various factories for other depart- ment i of the Government, the fees for which would amount to $3,514.01.

PERSONNEL.

Scope.

The personnel office handles the business connected with appointment, transfers, separations, and similar matters, and also the preparation and maintenance of Bureau directories, first-aid and injury

reports required by the United States Employees' Compensation

Commission, and special records, statistics, and reports required by

the administration of the Bureau, the department, and the Civil

Service Commission.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 269<

Personnel of Bureau.

During the year the Bureau's staff comprised 381 statutory employees and about 600 engaged in research and investigations

especially authorized by Congress. The statutory positions included

211 scientific positions, 55 office assistants, 76 engaged in the operation of the plant, and 40 in the construction. The personnel at. present consists of 981 regularly appointed employees, as compared

with 1,080 at the close of the fiscal year ended June 30, 1919. The

above figures show that the force has been reduced by approximately

100 employees during the past fiscal year. There were 2,408 personnel changes during the year. This total includes 850 separations

from the Bureau, of which 397 were resignations, 573 promotions,

and 836 appointments. The turnover in the permanent force of the

Bureau was therefore about 40 per cent, but if all separations and

reappointments be included this figure would be approximately 100

per cent. A detailed statement of the personnel changes is given in

the following table

:

Personnel Changes, 1918-19.

Nature of action. Appointments.

Competitive Excepted

Un'lassified Total permanent Temporary

Total appointments and separations

2S1

335

517 319

838

Eligibles.

The status of civil-service eligibles is practically the same as re- ported last year. Owing to the continued shortage of trained tech- nical and scientific men and the unusual demand for such assistants

in the industries, the Civil Service Commission can furnish directly

less than 10 per cent of the eligibles required'' for appointment to the

technical positions in the Bureau. B^is still necessary for the

Bureau to advertise and find applicjufts outside of the civil-service

registers and request them to take the examinations. This condition,

of course, was the cause of the large number of temporary appointments during the year, since it is usually necessary to make temporary appointment pending the completion of the necessary papers for

permanent appointment, y

Personnel Records.

Graphic records are kept of the staff and of the distribution of

salaries and positions by divisions and monthp^^These records are very useful in comparing the relative statu^of the divisions with

respect to personnel and expenditures for^eervices. A careful record

is kept of the educational status of the minor assistants, with a view

not only of advising them and encouraging them to secure advanced

schooling in their special subjects, but also to serve as a guide in
270 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

matters of training, promotion, and transfer. To facilitate the

transaction of Bureau business a carefujfy prepared personnel directory is mimeographed quarterly with supplements monthly.

Status of Work. /

Attention is called to the largfe number of speciaj^dministrative

reports which are required, srfch as the informairon called for by

the Reclassification Commission and other agen^fes. The reduction

in force leaves the staff at about a normal number to handle efficiently

the lines of personnel wobk proper. This office has in preparation

written specifications covering all classes of positions in the Bureau.

PUBLICATIONS.

New Publications.

During the fiscal year just closed the Bureau has issued 106 new

publications, 5 revised editions, 2 supplements to the Bureau's list of publications, and 21 reprints—13-1 publications in all. The 106 new publications comprise 50 scientific papers, giving results of new

scientific researches ; 37 technologic papers, giving results of new in- vestigations in the fields of engineering and general technology: 16

circulars, containing important compiled technical information in

the Bureau's field and useful to the industries,' and especially to sci- entific and technical laboratories ; and 3 miscellaneous publications.

The two supplements mentioned contain a list of Bureau publications issued since the 1919 edition of Circular 24, entitled "Publications of the Bureau of Standards." The supplements also give a list of the publications no longer available for free distribution by the

Bureau and contain a classified list of the libraries throughout the

country where the Bureau's publications may be consulted.

Announcements and Distribution.

In view of the many urgent requests received by the Bureau for more effective means of keeping the public informed of the results of the Bureau's work, special attention is being given to announcing

its new publications. Such announcement is made in several ways

:

(a) Through a monthly list issued by the superintendent of documents, of which a large edition is circulated ; (&) through the monthly

list of publications of the Department of Commerce, of Avhich more

than 10,000 copies are distributed to journals, industrial concerns, and libraries; (c) through technical abstracts of each new publication sent to the technical press; (d) through the Bureau's monthly

issues of the Technical News Bulletin; and (e) in Circular 2-t, the

classified, descriptive list of the Bureau's publications.

In order to more effectively reach the special industrial and scientific interests directly concerned with the Bureau's work, it is now

planned to issue card announcements to those who actually need the

publication, and to keep specialists posted on the technical work of

the Bureau.

The announcement of new publications is systematically handled,

notices being sent to technical journals, libraries, technical institutions, and carefully selected lists of specialists concerned with the

subjects treated.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 271

The publications of the year include the following

:

Scientific Papers.

The Effect of Rate of Teinperai ce Change on the Transformations in an Alloy

.Steel.

' Constitution and Metallography of Almnii urn and its Light Alloys with

Copper and with Magnesium.

Seme optica! and Photoelectric Properties of Molybdenite.

Standaidization of the Sulphur Boiling Point. A Standardized Method for the Determination of Solidification Points, Especially of Napthalene and Paraffin. Airplane Antenna Constants.

Reflecting Power of Stellite and Lacquered Silver. Location of Flaws in Rifle-Barrel Steel by Magnetic Analysis.

Spectral Photoelectric Sensitivity of Silver Sulphide and Several Other Substances. Measureine: ts of Wave Lengths in the Spectra of Krypton and Xenon. Oxygen Content by the Ledebur Method of Acid Bessemer Steels Deoxidized

in Various "Ways. Heat Treatment of Duralumin. Use of a Modified Rosenhain Furnace for Thermal Analysis. Photoelectric Spectrophotometry by the Null Method.

Equilibrium Conditions in the System Carbon. Iron Oxide, aid Hydrogen in Relation to the Ledebur Method for Determining Oxygen in Steel. Dependence of the Input Impedance of a Three-Electrode Vacuum Tube Upon

the Load in the Plate Circuit. Thermal Expansion of Insulating Materials. Variation in Direction of Propagation of Long Electromagnetic Waves.

Principles of Radio Transmission and Reception with. Antenna and Coil

Aerials. Determination of the Output Characteristics of Electron Tube Generators. Microstructure of Iron and Mild Steel at High Temperatures.

Constants of Radiation of a Uniformly Heated Inclosure. Concerning the Annealing and Characteristics of Glass.

Efflux of Gases Through Small Orifices. Methods for Computing and Intercomparing Radiation Data. Magnetic Testing of Straight Rods in Intense Fields. Distribution of Energy in the Spectrum of an Acetylene Flame.

Preparation and Reflective Properties of Some Alloys of Aluminum with

Magnesium and with Zinc. Relation of Voltage of Dry Cells to Hydrogen-Ion Concentration. A New Interferential Dilatometer. Contrast Sensibility of the Eye.

Turbidity Standard of Water Analysis.

Ionization and Resonance Potentials for Electrons in Vapors of Lead and

Calcium.

Vapor Pressure of Ammonia.

A New Form of Vibration Galvanometer.

A New Cadmium Vapor Arc Lamp.

Wave Lengths Longer Than 5.500 A in the Arc Spectra of Seven Elements.

Characteristics of Striae in Optical Glass. An Integration Method of Deriving the Alternating-Current Resistance and

Inductance of Conductors. The Double-Polarization Method for Estimation of Sucrose and the Evaluation

of the Clerget Divisor.

Critical Ranges of Some Commercial Nickel Steels. The Intercrystalline Brittleness of Lead. A New Spectropyrheliometer and Measurements of the Component Radiations

from the Sun and from a Qnartz Mercury Vapor Lamp.

Reflecting Power of Monel Metal, Stellite, and Zinc. The Spectro-Photoelectric Sensitivity of Thaloflde. An Electron Tube Transmitter of Completely Modulated Waves.

Notes on the Testing of Magnetic Compasses. Measurement of Hysteresis Values from High Magnetizing Forces. Variation of Residual Induction and Coercive Force with Magnetizing Force. A New Microphotometer for Photographic Densities.
272 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Technologic Papers.

Leakage Resistance of Street-Railway Roadbeds and Its Relation to Electro

. lysis of Underground Structures. Notes on the Graphitization of White Cast Iron Upon Annealing

A Comparison of the Heat-Insulating Properties of Some of the Materials

Used in Fire-Resistive Construction. Application of the Interferometer to Gas Analysis.

Mechanical Properties and Resistance to Corrosion of Rolled Light Alloys

of Aluminum and Magnesium with Copper, with Nickel, and with Manganese.

Tests of Flexible Gas Tubing.

Experimental-Retort Tests of Orient Coal. Belunior or Wrought Manganese Bronze Exposed to Corrosion While Under

Tensile Stress. The Determination of Free Carbon in Rubber Goods. Coking of Illinois Coal in Koppers Type Oven.

Effects of Glucose and Salts on the Wearing Quality of Sole Leather. Some Tests of Light Aluminum Casting Alloys—The Effect of Heat Treatment. Constant-Temperature Still Head for Light-Oil Fractionation. An Electrolytic Resistance Method for Determining Carbon in Steel. Materials and Methods Used in the Manufacture of Enameled Cast-Iron Wares. A Study of the Deterioration of Nickel Spark-Plug Electrodes in Service. The Properties of American Bond Clays and Their Use in Graphite Crucibles and Glass Pots. Direct Determination of India Rubber by the Nitrosite Method.

The Cadmium Electrode for Storage Battery Testing.

An Apparatus for Measuring the relative Wear of Sole Leathers, and the Results Obtained with Leather from the Different Parts of a Hide.

The Ultra-Violet and Visible Transmission of Various Colored Glasses. Estimation of Nitrates and Nitrites in Battery Acid. Physical Tests of Motor-Truck Wheels. Load Strain-Gage Test of 150-Ton Floating Crane for the Bureau of Yards

and Docks, U. S. Navy Department.

Investigation of the Compressive Strength of Spruce Struts of Rectangular

Cross Section and the Derivation of Formulas Suitable for Use in Airplane

Design. Area Measurement of Leather. Determination of Cellulose in Rubber Goods. Cements for Spark Plug Electrodes. Metallographic Features Revealed by the Deep Etching of Steel. An Investigation of the Physical Properties of Dental Materials. A Peculiar Type of Intercrystalline Brittleness of Copper.

Porosity and Volume Changes of Clay Fire Bricks at Furnace Temperatures.

Effects of Oils, Greases, and Degree of Tannage on the Physical Properties of" Russet Harness Leather. A Picnometer for the Deterniinaion of Density of Molasses. Extraction of Rubber Goods.

Stresses Caused by Cold-Rolling.

The Saybolt Viscosity of Blends. Circulars.

Protective Metallic Coatings for the Rustprooflng of Iron and Steel. Bibliography of Scientific Literature Relating to Helium.

Specifications for the Manufacture and Installation of Railroad Track Scales. Recommended Specifications for Basic Carbonate White Lead, Dry and Paste. Recommended Specification for Basic Sulphate White Lead, Dry and Paste. Recommended Specifications for Turpentine.

Recommended Specifications for Zinc Oxide, Dry and Paste. Recommended Specifications for Leaded Zinc Oxide, Dry and Paste. Recommended Specifications for White Paint and Tinted Paints Made on a1 White Base—Semipaste and Ready Mixed.

Recommended Specifications for Red Lead, Dry and Paste. Recommended Specification for Ocher. Dry and Paste. Operation and Care of Vehicle-Type Batteries. Recommended Specification for Iron-Oxide and Iron-Hydroxide Paints. Recommended Specification for Black Paint, Semipaste and Ready-mixed..
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 273

Inks—Their Composition, Manufacture, and Methods of Testing.

Recommended Specifications for Quicklime and Hydrated Lime for Use .in the Cooking of Rags for the Manufacture of Paper.

Miscellaneous.

Household Weights and Measures. Annual Report of the Director of the Bureau of Standards for 1919. Report of the Twelfth Annual Conference on Weights and Measures of the

United States. MAIL AND FILES.

Volume of Mail.

The volume of the Bureau's mail is steadily increasing. Approximately 150,000 pieces were handled during the past year in the file room proper, apart from other mails such as technical journals, catalogues, and documents, which would amount to as much additional.

In addition, through the dispatch room were transmitted 75,000

communications for the various divisions and sections.

Indexing and Filing.

The more important mail is specially recorded alphabetically by

writer, numerically by subject, and also by date. Of this class of

mail there were about 50.000 pieces. The perfecting of the case system of filing involved much extra work in the file room, and the

reduction in force increased the difficulty, but by careful planning

and efficient service the staff has brought the files into better condition than at any time in recent years. Special sorting units, designed

and constructed at the Bureau, facilitated the handling of communications. A system of compression guides installed in all filing units

of the central files has materially lightened the fatigue and labor

involved in inserting and removing material from the files. Loans of Correspondence.

A more systematic method of. making and charging loans has

been developed, so that record of the location of all letters is now

available.

PROPERTY AND STORES.

The office of property and stores administers all matters involved

in the accession, distribution, accountability, and records of property,

both equipment and supplies, and also the work involved in receipt

and shipment of instruments and materials of all kinds, including the

packing and shipping of all instruments tested by the Bureau. These

functions include the supervision of all Bureau storerooms, the shipping room, and delivery trucking. The work is now well organized

and proceeding efficiently.

During the year 64,800 items of property and supplies were re- ceived and inspected by the staff in charge of property and stores. The inventoried items of equipment included 15,000 pieces of apparatus or other equipment. Supplies were dispensed through the

storeroom to a value of approximately $62,000.

Approximately 12 tons of instruments and other technical materials passed through the shipping room per week, and 8 tons

additional transportation were required outside of the shipping room. Through the cooperation of the freight and express officers, the: 10613°—20 18
274 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Bureau has arranged to eliminate storage and demurrage charges heretofore unavoidably incurrepr owing'to transportation conditions in

Washington and the trucking facilities of the Bureau.

LIBRARY.

The Bureau's scientific and technical reference librae now contains 19,479 accessioned volumes chiefly in physics, engineering, and

chemistry. In addition there are currently received at the library

168 technical and scientific periodical publications.

There were accessioned during the past year 1,740 volumes, in- cluding 880 volumes of periodicals. The labor incident to ordering,

accessioning, cataloguing, binding, labeling, and circulating these

books is considerable.

The cooperation with other libraries in the city has been continued.

Books are loaned to other libraries, and in turn the other libraries,

especially the Library of Congress, have extended like courtesy to the Bureau. The broad field of the Bureau's work has made this

arrangement a very essential part of the library system.

PURCHASE.

Bids and Orders.

The Bureau orders issued during the year numbered over 8,000 and

included 1,500 exigency orders, 90 special orders through the Division

of Supplies, and 6,500 regular orders. The purchase office handled

1.600 proposals covering the needs of practically every part of the

Bureau's work, following the essential routine required by the Government. A systematic record of bids and purchases is maintained

to aid the Bureau's staff and facilitate the purchase work. The sec- tion prepares formal contracts for the larger purchases and enterprises. The routine connected with travel authorizations involvingtravel expenses also devolves on the purchase section. Nine hundred

travel authorizations and the records incident thereto were handled

during the year. The newly systematized catalogue library has effec- tively aided the Bureau's staff in finding sources of needed materials.

Organization and Records.

After a systematic study the purchase section has a very effective

organization and efficient system of routine and records for handling

the purchases of the Bureau. The analysis and charting of the sys- tem was completed during the year. The records are in excellent

condition. Under post-war conditions some sacrifice must be made,

and the reduction in force necessitated curtailing useful parts of the

work, which reduces somewhat the efficiency of the purchase system

as planned.

INFORMATION.

Technical Documents.

The information section maintains a reference file of general technical documents and these are listed and the various scientfic divisions

notified each week of new accessions. The documents may be withdrawn for consultation by those concerned. This section has thus

served as a clearing house for technical information other than that

given in the current scientific journals and new books received at the Bureau's library.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 275

Special Reports.

Statements are prepared, usually at the request of other Government departments or bureaus or industrial organizations, giving in- formation concerning certain specific phases of the Bureau's work.

During the year such technical reports were prepared on the fol- lowing subjects : Development of optical glass at the Bureau o*f Standards; description of the general work of the Bureau for the use

of a publicity work; the engineering work of the National Bureau

of Standards ; the work of the Bureau of Standards 1912-1920 ; aero- nautical work of the Bureau of Standards ; the present significance

of the war work of the Bureau of Standards ; the work of the Bureau

of Standards in the development of new and substitute materials

during the war; the facilities of the National Bureau of Standards

as regards the testing of ordnance equipment ; and a brief description of the Bureau of Standards with photographic illustrations. Once each month there is issued for publication in a scientific journal a brief statement of the work current during the previous month.

The section prepares a monthly " Technical News Bulletin " con- taining a summary of the more important work accomplished in the

various scientific divisions. This bulletin has been in greater demand

among industrial concerns than ever before and has proved very

useful in keeping manufacturers in touch with new technical information in the various fields covered by the Bureau.

Distribution of Documents and Directing of Inquiries.

Incoming inquiries from the industries and others are routed to the

members of the Bureau's staff best qualified to answer the questions.

The Technical News Bulletin above mentioned, supplied to a mailing list of more than 400, gives a large amount of information which

would otherwise involve considerable correspondence. This section

also refers incoming mail of a scientific character to the various

divisions of the Bureau.

Analyses and Compilations.

This section compiles special information on particular subjects

based on circulars and documents received by the Bureau. A card

index permits ready reference of mail relating to abstracts from the

journals of the various associations and similar material to the parties most concerned with the subject.

A progress of work record is maintained of important military

and industrial tests. This permits a systematic follow-up throughout

the Bureau for such tests.

Visitors.

Considerable time is devoted to interviews with persons visiting

the Bureau. In the case of visitors interested in some particular

technical subject, the information section endeavors to put them in

touch with those best qualified to answer their inquiries. Very often

visitors learn in this way of facilities which the Bureau possesses and which can be used to help them in their work. The value of the

personal contact thus established is considerable in making the re- sults of the Bureau's work available for use by the general public.
IV. ENGINEERING AND CONSTRUCTION.

POWER PLANT, BUILDINGS AND GROUNDS, AND TRANSPORTATION.

This division is concerned with the operation of the power plant, the maintenance of the transportation service, the installation and repair of electrical equipment and plumbing, and with the care of the buildings and grounds. OPERATION AND MAINTENANCE OF MECHANICAL PLANT.

Operation of Plant.

The mechanical plant comprises the heating, generating, and re- frigeration equipment ; compressed air ; vacuum and high pressure

"water services ; and storage batteries, stationary and portable. Very

few additions were made to the equipment, -which is consequently

seriously overloaded at times. A 125-kilovolt-ampere frequency

changer was installed for obtaining 3-phase 60-cycle power from the

3-phase 25-cycle main supply of the plant. This machine is re- quired essentially for the industrial building, in which are installed a large number of 3-phase 60 cycle motors. Fifty kilovolt-ampere were added to the transformer capacity of the 60-cycle commercial

service, bringing the present capacity up to 150 kilovolt-ampere in

this service. Several power plant appliances were installed for

observing plant performance and enabled a much more economical

operation of the boilers than had ever been obtained before. The

boiler plant at the kiln building was put into full operation and

gave entire satisfaction. Motor dm-es were installed for the chemistry building plenum fans and are giving far better service than the

old steam engines which they replace.

Need of New Power Plant.

It can not be too strongly emphasized that the present plant is entirety inadequate for the needs of the Bureau. As stated in the

previous annual report, its expansion under present conditions is quite impractical, as is also a complete remodeling of the whole

2>lant. A conservative new central plant adequate for immediate

requirements and capable of expansion to accomodate future growth

of the Bureau, should be constructed at once. The indefinite deferment of the construction of the new plant is unwise, in view of

the higher operating costs, poorer efficiency and service, and numerous operating difficulties that attend the present plant. In spite

of present high prices for materials and labor, the construction of a new plant at once would unquestionably prove an ultimate saving,

wdien all of the foregoing points are taken into consideration.

TRANSPORTATION.

With the aid of some trucks supplied to the Bureau by the War

Department, adequate transportation service has been furnished dur276
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 277

ing the year. New administrative policies were put into effect during

the year and the resulting improvement in service and efficiency has

been very gratifying. There is still room for improvement along

this line, but indications are promising for further betterment.

CONSTRUCTION AND REPAIR.

Electrical.

The installation, extension, and repair of all electrical wiring,

switchboards, motors, and similar equipment for the -various laboratories as well as for the mechanical plant are handled by this section.

The equipping of the various laboratories in the industrial building

and the new dynamometer building required a fairly large number of

mechanics throughout the year. The construction work at the industrial building was most extensive, including the installation of the

permanent alternating current and direct current distribution feeders

and risers, numerous motors, control panels, and various types of

electrical equipment in the different laboratories. Some temporary

wiring was installed, but most of the foregoing items were of permanent construction. In the dynamometer building the wiring, switchboards, etc., were completed for a number of dynamometers and for

auxiliary equipment for the altitude laboratories. Numerous other new installations were made throughout the Bureau. Construction

work for the mechanical plant included the installation of the motors

for the plenum fans in the chemistry building, resistance flue gas thermometers for five boilers in the north building, frequency

changer in engine room and feed lines to industrial building. Owing

to the pressure of so much new construction work, chiefly to provide

for the industrial building, maintenance work was not kept up as well as would otherwise have been the case, although progress was made in bringing such work up to date toward the end of the year. The maintenance of elevators, lighting circuits, switchboards, and

motors for various purposes in the mechanical plant will probably

receive more attention and inspection during the coming year, since

the new construction work has decreased in amount very decidedly.

Plumbing.

What has been said in regard to electrical installation and maintenance work applies very largely to the plumbing work also. The

most extensive construction work was carried on in the industrial

building, where the headers and risers for distribution to the laboratories of water, steam, gas, and air were installed, and the distribution

piping practically completed in all the laboratories. The air and gas

piping for all the kilns and furnaces in the kiln house was completed,

and a large amount of apparatus and equipment was put into operation throughout the industrial building. The remaining construction work, while not so extensive, was made up of a large number of

small jobs fairly well distributed. Extensive repairs were made to plant equipment such as pipe lines, valves, traps, etc., and mainte- nance work as a whole was well taken care of. There is a great deal

of plumbing and electrical construction work still on hand, but its completion is not as urgent as was that of similar work during the

past vear.
278 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Minor Construction.

This work includes small jobs of miscellaneous character that are not given out on contract, such as the building of temporary structures, construction and repair of roads, and repairs and alterations

to buildings. This work is very closely allied with the care of buildings and grounds. Foundations were constructed for the erection of

two steel wireless station towers; roads were constructed east of the

industrial building and at the wind tunnel and radio buildings; an

incinerator was built and has been in continual use ; building repairs

of every description were made. At the beginning of the year a large

amount of construction work still remained incomplete in the industrial building. Practically all such work has now been completed.

BUILDINGS AND GROUNDS.

Janitors and Laborers.

The work of this section is of more or less routine nature and comprises the cleaning of the many offices and laboratories of the Bureau

and the maintaining of sanitary conditions throughout. Although

five additional janitor positions were authorized for the year, the

care of the industrial and dynamometer buildings was added, so that there was still an insufficient number of men to properly care

for all the work. The scarcity of help necessitated rigid supervision

of all workmen, and very good results were obtained with the help

available. Such results were due mainly to the systematic manner

of handling the work, of granting leave, and of requiring strict accountability for all time the. men were at work.

Watchmen.

The duties of the watchmen consist in making inspections of the

buildings to prevent fire, theft, and damage by weather, etc., to the

property of the Bureau. They are also required to report anything

pertaining to the various functions of this division that are in need

of attention, such as repair of locks, leaks, and the like. Waste of

power, gas, water, etc.. is also minimized at night by requiring

watchmen to turn off all appliances using such facilities that are unintentionally left in operation in the laboratories. Owing to the

addition of two new buildings in the past two years, the watchmen's

force is no longer adequate for the safeguarding of the Bureau's

propertjr.

Grounds.

No extensive improvements were taken up due to the insufficiency

of funds for such purposes. Some additional temporary roads were

built, and others kept in repair. Routine work was very well handled and considerable progress made on cleaning up portions of

the grounds left in bad condition by building operations. A plan

is being worked out for permanent road construction and general

improvement of the landscape. The acquisition of adjoining land

to the north and south will greatly improve the Bureau's site.
V. GENERAL RECOMMENDATIONS.

Salaries.

Attention is again called to the necessit}7 for adjusting the salaries

of the scientific and technical experts of the Bureau to compare more

favorably with those paid by scientific and industrial laboratories, as well as educational institutions. It is to be regretted that this adjustment could not have been made during the year, since all scientific work of the Government has suffered to a greater or less extent. The

demand for men capable of undertaking scientific and technical in- vestigations is far greater than the supply; this, coupled with the

present rate of compensation in Government work, has lowered the

standard of workers available and greatly impaired the quality as well as the quantity of work. The number of changes in personnel

during the year has been many times that under normal conditions.

Here, again, the result has been decreased efficiency and a reduction

of output. It is realized that conditions throughout the year were

not such as to permit of a general reclassification of positions and adjustment of salaries, but it is urgently hoped that it can be done during the coming year. Many of the minor employees of the Bureau

are paid less than a living wage, and the salaries of mechanicians and

mechanics of all kinds are in many cases less than the salaries paid

for similar services in other bureaus of the Government, and in practically all cases much less than the compensation paid for the same

class of service in the industries.

The nature of the Bureau's work is such that it should command at

all times a certain proportion of the best scientific ability, the most

skilled workmen, and the most accurate clerical service.

Power Plant.

The power plant of the Bureau of Standards is entirely inadequate.

It consists of the original plant, designed to supply two buildings, and

two temporary boiler plants added later. These installations should

be combined in one plant capable of heating the various buildings. It should also provide the various electrical currents for power and ex- perimental purposes, as well as the refrigeration, compressed air,

vacuum, and other utilities required in scientific work. The need for

this plant has existed for the past three or four years, but it was not

possible to enlarge the original plant during that period except by

the addition of the temporary heating plants referred to. During

the present year the inadequacy of power generated at the Bureau,

ns well as that provided by the public service, has been such as to cause constant interruption of work, loss of time, and interference

with experimental work. In several cases valuable data and experimental work have been made useless by stoppage of the current.

279
280 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Specification, Inspection, and Testing of Materials Purchased by the

Government.

The Government method of purchasing materials and supplies of

all kinds by means of competitive bids often leads to injustice to the

manufacturer and loss of money to the Government unless based

upon correct specifications, methods of testing, and the testing of

deliveries. The bureaus of the Government recognize this and are

utilizing the Bureau of Standards as a testing laboratory to a far

greater extent than ever before, both in the preparation of standards

of quality and the testing of samples delivered. However, the de- mand for the work has grown to such an extent that the Bureau has

only been able to comply with a small part of the requests made for

such services. There is no question as to the necessity for the work,

or as to the economy of a central testing plant, but if the facilities of

the Bureau are not soon made more adequate for this work, the

bureaus of the Government will be compelled to set up their own

testing laboratories.

Cooperation with the Industries in Investigational Work.

The necessity for scientific research in connection with the industries was never as great as at present. New processes are being developed and old ones improATed, domestic materials are being substituted for imported ones, and the factors upon which the quality

or usefulness of a material or device depend are being studied as never before. In all of this, the work of the Bureau is more or less vitally involved, first from the standpoint of the standards and

methods of measurement, and second from the standpoint of the

efficiency gained by the working out of the fundamental problems

at a central laboratory, problems, the solution of which results in

data required by an industry as a whole.

The direct assistance given by the Bureau to the industries along

these lines would alone warrant its maintenance many times over. During the war the Bureau cooperated with the military departments in researches of many kinds. During the past year a special

fund was provided for such cooperation with the industries and an

analysis of the results will leave no question as to the usefulness of

or necessity for such work by the Bureau. The funds available for

this purpose during the coming year are entirely inadequate and it is earnestly recommended that in submitting the estimates for the

next year a suitable fund be requested for cooperation with the in- dustries in scientific research.

Buildings and Grounds.

The provision by Congress for the purchase of the small tracts of

land between the Bureau's present site and the streets to the north

and south, rounds out the Bureau's site with the exception of the

land between the present site and Connecticut Avenue on the east. The latter should be secured before it is built upon.

A more adequate fund should be provided for the care of the

buildings and grounds. The former are not sufficiently well kept

with the force available. The addition to the site will require

additional grading, cleaning up, and maintenance.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 281

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

important service can be made more efficient by providing a small

depot centrally located, for although every effort has been made to handle this from Washington, experience has shown that such a small

substation is necessary. Respectfully,

S. W. Stratton,

Director.

To Hon. J. W. Alexander,

Secretary of Commerce.

o

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