ANNUAL REPORT

OF THE

DIRECTOR

UREAU OF STANDARDS

TO THE

SECRETARY OF COMMERCE

FOR THE

FISCAL YEAR ENDED JUNE 30, 1921

(Mijcellaneous Publications—No, 47)

WASHINGTON

GOVERNMENT PRINTING OFFICE

1921

ANNUAL REPORT

OF THE

DIRECTOR

BUREAU OF STANDARDS

TO THE

SECRETARY OF COMMERCE

FOR THE

FISCAL YEAR ENDED JUNE 30, 1921

(Miscellaneous Publications—No. 47)

WASHINGTON

GOVERNMENT PRINTING OFFICE

1921
Persons on a regular mailing list of the Department of Commerce should give

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

Washington, D. C," of any change of address, stating specifically the 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 publication is no longer desired.

2
CONTENTS

Chart showing functions of Bureau facing 17

I. Functions, organization, and location 17

1. Definition of standards 17

Standards of measurement 17

Pliysical constants (standard values) IS

Standards of quality . 18

Standards of performance 19

Standards of pi'actice 20

2. Relation of the Bureau's work to the public 20

Comparison of standards of scientific and educational institu- tions or of the public with those of the Bureau 20

Work of the Bureau in an advisory capacity 21

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

Assistance in establishing exact standards of measurement

needed in industries 21

The collection of fundamental data for the industries 22

Simplification of standards 22

Elimination of industrial wastes 23

Training of experts in various industrial fields 23

4. Relation of the Bureau's work to the Government 24

Comparison of standards of other Government departments with

those of the Bureau 24

Performance of tests and investigations and the collection of

scientific data of a fundamental nature 24

Advisory and consulting capacity 24

The Bureau as a testing laboratory and its work in the preparation of specifications on which to base the purchase of materials 25

5. Organization 25

6. Location 27

II. Scientific and technical divisions 28

1. Weights and measures , 28

General ' 28

The importance of weights and measures 28

Length ' 28

Investigations in precision length measurement 28

Status of standards ' 2&

Routine testing 29

Visitors and travel 30

Mass 30

Tests 30

Rejections ^ 31

Standards tested for the States and for manufacturers 31

Assistance to the Motor Transport Corps 31

Shortening the work on high precision tests 31

Changes in weight of celluloids 31

Standards and apparatus 32

Recommendations 32

Time 32

Investigation of stop watches 32

Drum chronographs 33

Advisory work 33

Improvements in equipment 33

Routine testing__ 33

Future work 34

Additional equipment 34

5
4 CONTENTS.

II. Scientific and teclinical divisions—Continued.

1. Weiglits and measures—Continued. Page.

Capacity and density 34

Research 34

Testing , 85

Visitors 86

Additional space needed 36

Gas measurement '! ^_ 36

Field work 86

, Research and preparation of ta'bles 37

Routine testing of gas meters 37

Expansivity of solids 87

Research, investigation, and tests 37

Travel '38 Improvement of equipment 38

Commercial scales 39

Investigation of railroad track scales 39

Testing and calibration of master scales 40

Bureau of Standards' master track scale 40

Mine-scale investigation 41

Grain scales 42

Quick-weighing scales 42

Adjustment of scales 43

Cooperation with States and other interests in weights and

measures administration 43

Cooperation with States 43

Fourteenth Annual Conference on Weights and Measures 44

New legislation , 45

Compilation of weights and measures laws 45

Cooperation with other Government departments 45

Cooperation with outside interests 46

Gauge section 46

Research and design 46

Testing of gears and gear-cutting tools 47

Routine testing of gauges 48

Testing of gauges for commercial concerns 48

Finger-ring gauges 49

• Shopwork 49

Travel 49

National Screw Thread Commission 50

American Society of Mechanical Engineers' Sectional Comm ttee on uiiiflcation and standardization of screw threads. 50

American Society of Mechanical Engineers' Sectional Committee on plain limit gauges for general engineering work_ 50

Standardization of buttons 50

Publications 51

Progress report of National Screw Thread Commission 51

Jewelers and Silversmiths' Circular 51

Thermal expansion of copper and its alloys 51

Report of annual conference . 51

Screw-thread pitches 51

Thermal expansion of metals 51

Testing of large capacity scales_l 51

Technical data and information 52

2. Electricitv 52

General 52

Scope of the electrical work 52

Public utility investigations 53

Standards of resistance 54

Routine testing 54

International comparison of standards of resistance 54

Refinements in resistance measurements 54

Units of resistance '. 55

The statement of the conducting quality of conductors 55

Resistance of human body 55

Electrical method for the measurement of the rate of natural corrosion in sheet metal 56
CONTENTS. -5

II. Scientific and technical divisions—Continued.

2. Electricity—Continued.

Inductance and capacitance . 56

Inductance and capacitance laboratory 5&

Inductance research 5*5 Capacitance research 57

Ballistics and allied problems • 57

Cooperation with Navy Department 57

Study of the variation of gun pressures vt^ith time 57

Primer explosion times — 57

Ejection velocities 57

Firing-time intervals 58

Interior ballistic formulas 5S

Pressure in recoil cylinders 58

Velocity of the projectile inside the bore of the gun 58

Photography of projectiles in flight 58

Sao Paulo report 58

Measurements on the U. S. S. Tennessee 58

Physical constants for submarine mines 59

Design of oscillographs — 59

Investigations of turret movements and strains during gunfire 59

Study of soluble washers 59

Electrical measuring instruments 59

Testing of electrical instruments 59

Electrical tests of ignition apparatus 59

Cooperation with national associations 69

Cooperation with manufacturers 60

Development of new apparatus . 60

Magnetic measurements ^ 61

General magnetic measurements . 61

Magnetic analysis 61

Magnetic compasses 62

Miscellaneous activities : 62

Photometry and illuminating engineering 62

General problems in photometry ^ 62

Instruments for measurement of reflected light 63

New specifications for incandescent electric lamps 63

Inspection and life tests of incandescent lamps 64

Interlaboratory comparison of lamp measurements 6.5 Radio communication 6-5 Radio research and Information 65

Standardization of terminology 66

I Variations of radio signal intensity 66

Measurement of received signal intensity 66

Antennas 66

International Union on scientific radio telegraphy 66

Electron tubes ^ 66

Radiotelephony 67

Phenolic insulating materials for radio use 67

Miscellaneous insulating materials 67

Radio testing 67

Measurements of telephone receivers 68

Properties of inductance coils 68

Airplane radio 68

Direction finding 69

Radio fog signaling 69

Radio receiving sets 69

Radio broadcasting 69

Miscellaneous applications of radio 69

Electric batteries 70

Tests of electrical batteries 70

Electrical performance of dry cells 70

Storage-battery investigations 70

Effect of low temperatures on the voltage of batteries ^_ 71

Comparison of American and foreign make of dry cells 71

Signal Corps textbook on radio telegi-aphy 71
CONTENTS.

II. Scientific and technical divisions—Continued.

2. Electricity—Continued.

Electric batteries—Continued. Page.

Preparation of specifications for electrical batteries 72

Standard cells ' 72

Radio activity and X-ray measurements 73

Gamma-ray measurements of radioactive material 73

Self-luminous materials 73

X rays 74

Electrolysis prevention 74

Electrolysis problem among public utilities 74

Economic Importance of tbe electrolysis problem 75

Inconvenience and hazard due to electrolysis 75

Investigation of lead corrosion troubles iu St. Louis 76

Cooperation with the American Committee on Electrolysis 76

Development of apparatus for making electrolysis surveys 77

Electric telemetric devices 77

Safety engineering and safety standards 78

National electrical safety code 78

Electrical safety conference 79

Industrial safety standards 79

Heads and eyes code 80

Logging and sawmill code 80

Aeronautical safety code 80

Gas engineering 81

Gas-appliance investigations 81

Gas-service inspections 81

Investigation of the cost of manufacture and distribution of

gas in -the District of Columbia 82

Cooperation with the California Railroad Commission 82

National gas safety code " 82

Electrici^.l and related service standards 82

Standards for electric service • 82

Standards for heating service S3

Standards for water service .. 84

Engineering standardization directory 84

Telephony 84

Telephone service studies 84

Other telephone problems . 85

General condition of the division 86

Publications ^ 86

3. Heat and thermometry : 88

Thermometry ^ 88

Clinical thermometers : 88

Laboratory thermometers , 89

Thermometer testing 90

Platinum resistance thermometers-^ 91

High, temperatures 91

Industrial pyrometry 91

Standard samples for thermoraetric fixed points 92

Research in pyrometry 92

Heat treatment of glass : 93

Investigation in electronics 94

Heat measurements 94

Refrigeration constants 95

Specific volumes of superheated vapors 95

Specific heat of gases 95

MoUier chart . 96

Pressure-relief diaphragms 96

Cryogenic laboratory (low temperatures) .

. 97

Production of low temperatures 97

Production of liquid air on a laboratory scale 97

Fire-resistive properties of structural materials 97

Fire tests of concrete columns 98

Fire tests of building columns 98

Fire tests of brick walls 98

I
CONTENTS. 7

II. Scientific and technical divisions—Continued.

3. Heat and tliermometry—Continued.

Fire-resistive properties of structural materials—Continued. Page.

Hollow-tile investigation 99

Strength of materials at high temperatures 100

Miscellaneous fire-resistance activities 100

Automotive power plants, fuels, and lubricants 100

Altitude laboratory 100

Ignition 101

Lubrication 101

Carburetion 102

Phenomena of combustion 102

Cooling problems 103

Truck rear axles 103

Standard method of testing brake linings 104

Miscellaneous 104

Testing, information, and publications 105

Thermometer, pyrometer, and heat tests 105

Information, cooperation with societies, etc 105

Publications 106

4. Optics : 108

Spectroscopy 108

Standard wave lengths 108

Investigation of arc spectra 109

Spectroscopic analysis 110

Spectrum tubes 110

Photosensitizing and hypersensitizing 111

Polarimetry 111

Polarimetric work 111

Standardization of sugar manufacture 112 . The rare sugars 112

Polarimetry of oils 113

Quartz-control plates 113

" Reaction " of sugar products 114

100° point of the saccharimeter scale 115

Cooperation with customs laboratories 115

Grading of commercial sugars 115

Color of sugar and sirups 115

Preparation of levulose 116

Clerget analysis of sucrose 116

RafRnose in beet-sugar products 117

Testing of molasses ^ 117

Beverage sirups 118

Molasses formation 118

Decolorizing agents 118

The laboratories for sugar technology 119

Special appai-atus and construction 120

Gradation of sugars by sieve analysis 120

Diffusion process in sugar m.anufacture 120

Storage and shipment of sugar 120

Production of mannite 120

Crystallization 121

Composition of sirups of high density 121

Solubilities of dextrose 122

Candy test for sugar 122

Baume scale 122

Supplies for customs service ^ 122

Properties of quartz at high temperatures 123

Adjustment and standardization of polariscopes 124

Rotation dispersion of sugars 124

Saccharimeter light filters 125

Standard samples 125

Tests on cover glasses for polariscope tubes 125

Investigation of strains in glass by polariscopic methods 126

Thermal properties of glass 126

Annealing of glass 126
8 CONTENTS.

II. Scientific and teclinical divisions—Continued.

4. Optics—Continued.

Polarimetry—Continued. Page.

Hardened glass - 127

Refractometer in sugar analysis 127

Commercial production of pure dextrose 127

Cadmium vapor arc lamp 128

Society of Sugar Chemists and Technologists 128

Colorimetry 128

General nature and scope of the Bureau's work in color

standardization and colorimetry 128

The standardization of " white light " 129

The color of various illuminants 130

The relation between color and the spectral distribution of

light 131

A direct reading spectrophotometer for liquids 131

A new study of the leucoscope 131

The spectral transmissive constants of dyes 131

The spectral transmissive constants of vegetable coloring

matters ^ 132

The color and spectral transmissivity of vegetable oils 132

The spectral reflection of various materials 132

Investigation of the Lovibond color scale as used in the color

grading of vegetable oils 132

An examination of the Munsell color system 132

Refractometry and optical instruments 132

Range-finder investigation 133

Standardized laboratory telescopes 133

Design of a high-precision refractometer 133

Design of a universal polarimeter 133

Intensifying lens for a large aperture astronomical reflector- 134

Design of cameras for the Navy 134

Special test of lenses for the Air Service 134

Radiometry 135

Infra-red transmission spectra 135

Spectral transmission screens 135

A portable vacuum thermopile 135

Methods for testing glasses used for protecting the eye from

thermal radiation 136

Exclusion of ultra-violet solar radiation from buildings 136

[. ! Photoelectrical investigations 136

Dispersoids 137

Stratified soap films and molecular reality 138

TJltramicroscopic study of varnishes 138

Work on a turbidity standard 138

Interferometry 138

Thermal expansion 138

Calibration of length standards 138

Ruling of line standards using light waves as fundamental

length standards 139

Index of refraction of glass 139

Testing of plane surfaces 139

Photographic technology 139

Sensitometry 140

Color sensitizing of photographic plates by bathing 140

Searchlight investigation 140

Completion of a focus-testing apparatus for searchlight

mirrors 140

Design of a simple reflectometer for testing the reflecting

power of mirrors 140

Effect of diffusion of light from a searchlight beam 140

Testing, information, and publications 141

Testing 141

Information, activities in societies, etc 141

Publications 142

5. Chemistry 144

Electrochemistry 144

Electroplating investigations 144
CONTENTS, 9

II. Scientific and technical divisions—Continued.

5. Cliemistry—Continued. Page.

Gas chemistry — 146

Balloon fabrics 147

Application of thermal conductivity method of gas analysis

to industrial uses _ 147

Hydrogen investigation 148

Airship slide rule 149

Bibliography of gas literature 149

Gas analysis 149

Reagents and apparatus 149

Chemical reagents and apparatus » 149

Platinum research 150

Platinum theft 151

Miscellaneous tests 151

Analytical methods and standard samples 151

Standard analyzed samples 151

Cooperation in the analysis of British chemical standards 152

Cooperation in the development of standard analytical

methods 152

Researches in progress 152

Lubricating oils, rubber, paper, textiles, ink, and glue 153

Airplane dopes 153

Balloon fabrics 153

Rubber 153

Textiles 153

Writing and copying inks 154

Stamping, marking, and related inks 154

Printing inks 154

Typewriter and similar ribbbons 154

Carbon paper 154

Glue, mucilage, and paste 154

Lubricants — 154

Metals, cements, bituminous materials, etc 155

Built-up bituminous roofing 155

Prepared roofing, plastic cement, and roof coatings 156

Concrete drain tile 156

Mastic fiooring 156

Black ship glues (calking pitch, marine glue) 156

Smokestack paints 156

Belting compounds 157

Lime investigation 157

Miscellaneous work 157

Paint, varnish, and soap 157

Interdepartmental committee on paint specification standardization 158

Chemical testing 158

Publications in chemistry 158

6. Engineering physics 159

General 159

Engineering instruments 160

Current-meter I'ating station 160

Calibration of instruments 160

Hydrogen cylinder valves 160

Safety release device for hydrogen valves 160

Radiator return line valves 161

Air measurements of vacuum cleaners 161

Fire extinguishers 161

Miscellaneous engineering tests 161

Sound measurements 161

Sound source 161

Intensity measurements of sound 162

The sound field of a parabolic mirror 162

Radiation detector for airplanes 162

Building acoustics 162

The electron-tube drive of tuning forks and other apparatus 163
10 CONTENTS.

^

II. Scientific and teclinical divisions—Continued.

6. Engineering physics—Continued.

Sound measurements—Continued. Page.

Radio time recorder 163

Solenoid clironograph 163

Piezo-electric pressure gauge 164

Sound ranging 164

String galvanometer 164

Oscillograph element without damping fluid 164

Aeronautic instruments 165

Altitude effect on air-speed indicators 165

Diaphragm investigation 165

Hysteresis in Bourdon tubes 166

Bimetallic bars 166

Aircraft sextants 166

Aircraft compasses 166

Turn indicators 166

Precision barometer 166

Temperature compensated altimeter 167

Precision barograph 167

Rate-of-climb indicator, model No. 3 167

Recording rate-of-climb indicator 167

Combined statoscope and rate-of-climb indicator 167

Ground-speed indicator 167

Sextants 168

Astronomical position finder 168

Horizontal angle indicator 168

Tachometers 168

Air-speed indicator for dirigibles 168

Ballonet volume indicator for dirigibles 169

Compasses 169

Standard testing sets for field use 169

Foreign representative 169

Instrument collection i 169

Routine testing 170

Flight tests on aeronautic instruments 170

Aerodynamical physics 170

Aerodynamical characteristics of aircraft bombs 171

Investigation of flo-^v around wind screens : 172

Resistance of spherical bodies 172

Ventilation problems 173

Testing of instruments and airplane models 173

Publications 173

7. Structural, engineering, and miscellaneous material 174

Physical tests of structural materials 174

General scope of work 174

Tests of large H columns 175

Strain-gauge measui-ements on welded and riveted tanks 176

Permissible working stresses in steel buildings 177

Strain-gauge test under load of the Arlington Building 177

Investigation of the strength of hollow-brick walls 177

Investigation of the fatigue resistance of sheet metal 178

Investigation of the impact resistance of sheet metal 178

Investigation of body-bound bolts 178

Investigation of the strength of screw threads for the

National Screw Thread Commission 179

Streamline stay rods 179

Investigation of the failure of a duralumin airplane elevator. 180

Calibration of large testing machines 180

An investigation of oxyacetylene welding and cutting blowpipes 181

Summary of tests 181

Publications 182

General information furnished 183

Cement, concrete, stone, gravel, and sand 183

General outline 183

Constitution of cement 184
CONTENTS. 11

II. Scientific and technical divisions—Continued.

7. Structural, engineering, and miscellaneous material—Continued.

Cement, concrete, stone, gravel, and sand—Continued. ^age.

Sorel cement 184

Test of a concrete and hollow-tile floor reinforced in two

directions 18-1 Moments and stresses) in slabs 185

Specifications for concrete and reinforced concrete 185

Shearing strength of concrete beams 186

Durability of concrete in alkali and sea water 186

Automatic freezhig and thawing apparatus . 186

Discoloration tests on Indiana limestone 186

Colorless waterproofing materials 187

Investigations of slate 187

General tests on concrete floor treatments 187

Volume changes in mortars and concretes 188

Air analyzer ^ 188

Standard cement sieves 188

United States standard sieve series 188

Standard samples 189

Concrete tanks for oil storage 189

Measuring the consistency of concrete 190

Measuring the time of set of concrete 190

Tests of concrete used in Georgetown bridge 191

Concrete accelerators 191

Slag as concrete aggregate 191

Investigation of a special cement 191

Miscellaneous tests 192

Testing of cement for Government purposes 192

Foreign cement specifications 193

Publications relating to cement and concrete 193

Lime, gypsum, and sand-lime brick 194

General 194

Hydrated lime in concrete 194

Panel tests of lime plaster ^ , 194

Measurement of plasticity 195

Quick-setting of lime plaster 195

Normal consistency of sanded gypsum plasters 195

Effect of fineness on other properties of calcined gypsum 195

Plastic gypsum 195

Action of retarders on gj'psum 196

Adhesion between gypsum and cement 196

Effect of temperature of calcination on the properties of

calcined gypsum : 198

Acoustics of wall plasters 197

Colored plaster ^ 197

Measurement of the color of plaster 197

Specifications for plastering sand 197

Effect of the grading of sand on the properties of sand-lime

brick 197

Lime-water-glass paint 19S

Tests 198

Cooperation 198

Publications 198

Rubber 1 199

New equipment 199

Rubber tubing 199

Rubber jar rings for canning 199

Power losses in automobile tires 200

The effects of compounding ingredients on properties of

rubber 200

Rubber analysis 200

Miscellaneous materials 200

Cooperation with the rubber industry 201

Specifications 201

Publications 202
12 CONTENTS.

II. Scientific and teclinical divisions—Continued.

7. Structural, engineering, and miscellaneous material—Continued. Pae^- Leather 202

Sole leather 202

Upper leather 20a

Membrane for air-speed recorders 203- Rabbit-skin leather 20S

Preservative for shoes 204

Specifications 204

Publications issued 204

Routine tests 204

Textiles 204

General facilities 204

Specifications 204

National Association of Dyers and Cleaners 205- Cooperation with the National Association of Woolen Manufacturers 205- Annual technical textile conference 205

Microscopy of textiles 20.5- Balloon fabrics 20&

Length tolerance of blankets 20T

Utilization of low-grade cottons 207

Cloth variables investigation 207

Filter press cloths 20S

Properties of cotton fibers of different states of maturity , 208- Suitability of paper and cotton bags in relation to burlap

sandbags 208- Florida or Simnish moss 209' Numbered cotton ducks 209' Testing of cotton ducks 209' Artificial silk 209

Investigation of waste silk materials 209

Chemical retting of flax 210' Pompier belts 210' Asbestos brake linings 210' Conveyer belts 210

Umbrella cloths 2ia

Cloth-measuring tapes 211

Printers' blankets 211

Routine testing 211

Information . 211

Cooperation with societies and textile organizations 211

Publications 212- Paper 212: General conditions , 212

Stain for sulphate pulp in -paper 212' Condenser paper 212

Sizing quality of paper 213: Paper testing 213- Paper bags for lime and cement 214

Paper and cotton bags for use as sandbags 214

Waterproofing of paper 215

Tearing strength of paper 215

Newsprint 216

Testing of blotting paper 216

Carbon paper 216

Testing and information 216

Relation to the paper industry 219

Publications 219

Lubricating oils 219

Standardization of instruments 219

Plasticity 219

Piiysical tests 220

Cooperative work 220

8. Metallurgy 220

General 22a

Position of the Metallurgical Division__ 220
CONTENTS. 13

II. Scientific and teclinical divisions—Continued.

8. Metallurgy—Continued. Fage.

Optical metallurgy '- 221

Metallographic etching reagents and methods 221

Deep etching as a means for metallographic study 222

Structural changes accompanying the tempering of hardened

steels = 222

Intercrystalline brittleness of soft metals as a result of

corrosion 222

Corrosion of chromium steels 223

Distribution of phosphorus in low-carbon steels 223

Effect of abrasion upon the hardness of steel 223

Microphotographical work 224

Use of etched balls in the Briuell hardness test 224

Proposed new investigations 224

Thermal metallurgy 224

New equipment 22-i

• Effect of heat treatment on properties of structural steels— 22o

Artificial seasoning of hardened steels 225

Tensile properties of steels at high temperatures 225

. Thermal analysis 226

Effect of surrounding atmosphere on heat treatment 227

Heat treatment of carbon steel 227

Proposed new investigations 227

Mechanical metallurgy 22S

Effect of rolling conditions on the properties of a medium

carbon steel 228

Fish scaling of enamels 22S

Bearing metals 228

Equilibria of tin-rich ternary alloys 229

Strength of solders and soldered joints 229

Fusible metals for helium relief valves 229

Thermal stresses in chilled iron car wheels 229

Graphitization of v/hite and gray cast iron 230

Thermal stresses in steel car wheels 230

Corrrosion of iron-silicon alloys 230

Titanium treated v. untreated rails 230

Pure platinum wire 233

Metal specifications 231

New apparatus 231

Continuation work and new work 231

Chemical metallurgy 232

Gases in metals 232

Pure metals and alloys 233

Refractories 234

Chemical metallurgy standards 235

Invar (36 per cent nickel steel) 236

New equipment—_ 230

Proposed work 236

Experimental .foundry l ' 237

Experimental and practical castings 237

Molding-sand investigation 237

Weathering of art bronzes 237

Government bronze and its substitutes 237

Items of military interest 237

Erosion of machine-gun barrels 237

Corrosion of metals by ammonia gases 238

Development of light armor plate 238

Tensile fractures of gun steels 238

Armor-piercing bullet cores 238

Miscellaneous tests for ordnance 239

Manufacture and properties of steel plates for light armor 239

German motor-truck parts 239

Precision altimeter 239

Research associates 240

Iron in brass 240

Sherardizing 240
14 CONTENTS.

II. Scientific and technical divisions—Continued.

8. Metallurgy—Continued.

Research associates—Continued. ^^se

Researches on monel metal 241

Study of nickel 241

Deoxidizers and slags 241

Effect of different elements on red shortness of iron 243

General activities 243

Tests 246

Circulars of information 247

Cooperation with technical and scientific organizations 248

Committee memberships 248

Conferences , 248

Exhibit 248

Correspondence and travel 248

Publications 249

9. Ceramics 251

Clay products 251

High-fire porcelain glazes 251

Earthenware bodies and glazes 251

Solubility of some feldspar frits 252

Properties of foreign and domestic ball clays 252

Hopi Indian pottery 252

Hardness of glazes 252

Development of a satisfactory chrome-tin matt glaze maturing between cones 04 and 01 252

The effect of replacements of sand flint by crj'ptocrystalline flint in pottery bodies 253

Safe rate of water smoking 253

Casting of terra cotta 253

Effect of time of drying on total shrinkage of clay 253

The use of special oxides in porcelain bodies 253

Cooperative investigation of problems relating to architectural terra cotta 251

Optical glass 254

Scope of work 254

Melting 254

Annealing 254

Optical glass for Navy Department 255

Investigation of colored glass 255

Specifications 255

Cooperation 255

Information 255

Refractories 256

Transverse strength of fire-clay tile 256

Study of bond clays for glass pots 256

Combaiations of siliceous claj's with aluminous grog compared with reverse combinations 256

Special material for refractory tubes 256

Enamels • 257

Elimination of " fish scaling" of enamels on iron and steel 257

Wet-process enamels for cast iron 257

White enamels for copper 257

Relation of composition of enamels to solubility in acids 258

Replacement of tin oxide in enamels for sheet steel 258

Testing and information 258

Cooperation with technical societies 259

Cooperation with commercial organizations 259

Publications 259

III. The office 260

General 260

Finance 260

Funds 260

Appropriation statements 260

Summary of tests 263

Personnel 263

Death of two division chiefs 264
CONTENTS. 15

III. The office—Continued. ^agePurchase 264

Property and stores 264

Mail and files 265

Volume of mail 265

Model letters and clerks' instructions 265

Library 265

Accessioned volumes 265

Technical journals 265

Circulation 266

Information 266

Technical documents 266

Special reports 266^ Directing inquiries 266

Publications 266" Distribution 266

Publications issued during the year 26T

IV. Engineering and construction 270

Operation and maintenance of mechanical plant 270

Operation of plant 270

Construction and repair 270

Electrical 270

Plumbing and pipe fitting 270

Buildings and grounds 271

Grounds 271

V. General recommendations 272

Salaries 272

Power plant _, ^ 272

Care of buildings 273- Buildings and grounds 273


NATIONAL BUREAU OF STANDARDS

Washington, D. C.

1921

FUNCTIONS

Development, construction, custody, and maintenance

of reference and working

STANDARDS -

and their intercomparison, improvement, and application

in science, engineering, industry, and commerce.

04984—COM 1921. (To face page 17.)
REPORT

OF THE

DIRECTOR, BUREAU OF STANDARDS.

Department of Commerce,

Bureau of Standards,

Washington, July 1, 1921.

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

Bureau of Standards for the fiscal year ended June 30, 1921.

I. FUNCTIONS, ORGANIZATION, AND LOCATION.

Before describing in detail the various scientific and teclinical

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 fimdamental 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 prepared 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 prepared 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

64984—21 2 17
NATIONAL BUREAU OF STANDARDS

Washington, D. C. 1921

FUNCTIONS

Development, construction, custody, and maintenance

of reference and working

STANDARDS

and their intercomparison, improvement, and application

in science, engineering, industry, and commerce.

1149S-1— COM lO'Jl, (To face page 17.)

STANDARDS

1 STANDARDS OF MEASUREMENT __ - ttaencVtd working standards for measurements of all k.nds, mcludrng

fundamental and derived STANDARDS OF MEASUREMENT for e«pressme

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

'"BrirfiTion, speciticion, or material sta.dard. coverinB, for exan.pl., l.nBth, .r..,

and volume' m^ss, weight, density, and pressure; he.,, light, elec.r.c.ty. and rad.oaet.v.ty,

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.

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.

PURPOSE

To aid ACCURACY IN INDUSTRY through uniform and correct measures; To ASSIST COMMERCE IN SIZE STANDARDIZATION of containers and

products; To PROMOTE JUSTICE IN DAILY TRADE through systematic inspection and regulation; To facilitate PRECISION IN SCIENCE and TECHNOLOGIC RESEARCH

through calibration of units, measures, and instruments involved.

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

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.

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, an^ performance.

Collation of standard data, numerical magnitudes, and ranges of the pertinent factors

delining quality, safety, economy, convenience, and efEciency.

To CLARIFY THE UNDERSTANDING between maker, seller, buyer, jnd luer, 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.

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.

18 REPORT OF DIRECTOR OF BUREAU OF 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 energj^ 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 phj^sical measurement. Their determination involves the piost difficult and precise work in all branches

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

engaged in the scientific or technical work where these constants are

used.

Standards of Quality.

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

form of a sample of that material with which other materials of the

same kind can be compared, but this is generally a makeshift of the

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

reliable specifications in terms of measurable properties; that is to

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

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

measurement of those properties by means of the usual standards of

measurement. A certain kind of steel, a cement, a paint, an oil, 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
BEPORT OF DIRECTOR OE BUREAU OF STANDARDS. 19

properties to be measured or its constituents determined ? These are

questions for the laboratory to answer and involve physical and

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

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

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

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

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

L the Bureau's investigations in connection with the properties of

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

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

the necessary tests to ascertain whether or not the material supplied

is in accordance with the specifications.

The actual testing of materials by the Bureau of Standards to

ascertain whether or not they comply with specifications is confined

almost exclusively to Government purchases, but in making these

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

to make many investigations concerning the properties of materials,

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

value in placing Government purchases on a correct business basis,

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

the information gained in testing Government supplies are even

more important to the general public and are distributed in the form

of suitable publications.

The Bureau does not compete with private testing laboratories,

but endeavors to assist them by the development of standard specifications, methods of measurement, and other matters where uniformity is desirable, much of which information, as stated above, is

secured in connection with the testing of materials purchased by the

Government and a close observation of their use. The time is not far distant when it will be required that all material

bought and sold shall be as represented, but it should be kept in mind

that this is impossible except in the case of those materials for which

proper standards of quality and methods of measurement have been

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

only part}'' benefited in the development of such standards. On the

contrary, the manufacturer, first of all, is interested in all things

which affect the quality of his product. The research work and tests condvicted by the Bureau have done a great deal in pointing out those

proj^erties upon which the quality of a material depends, and in connection with this work it is worth while to remember that not only

are the important properties pointed out, but the ways for measuring

them are indicated. The facilities of the Bureau are not extensive

enough to permit it to conduct all the research work in which the

manufacturers of this country would like it to engage, but the value

j and importance of its work along these lines is becoming more and

I more appreciated and is being extended each year.

Standards of Performance.

The value of an instrument, device, or machine almost always depends upon the efficiency of its performance. In such cases it is

necessary to state the performance desired or guaranteed in terms
20 KEPOET OF DIRECTOR OF BUREAU OF STANDARDS.

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

form of a specification, but specifications are useless unless based

upon correct scientific and mechanical principles and supplemented

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

or not the specification or guaranties have been complied with.

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

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

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

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

secure information upon which to base proper standards of performance involves investigations quite as scientific in character and

as difficult as in the case of other standards, as well as a knowledge

of technical and manufacturing processes. In this field, as well as

in the field dealing with the properties of materials, the Bureau

has had the hearty cooperation of the various Government experts,

manufacturers, engineers, and technical societies. It has conducted

many investigations which have led to improvements in machinery,

appliances, and manufacturing processes.

Standards of Practice.

Standards of practice are generally involved in the enactment of

laws when technical and scientific matters are concerned, in the

ordinances relating to the regulation of public utilities, and in the

establishment of building and safety codes. lake standards of

performance, they are dependent upon standards of measurement and

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

the work, where national uniformity is desired—fields which are not

covered in private laboratories.

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

Comparison of Standards of Scientific and Educational Institutions

or of the Public with Those of the Bureau.

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

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

scientific and technical investigations of the highest grade, involving

the most competent expert services and the best scientific equipment.

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

making the results available and useful to the public.

The Burea/u compares with its own standards of measurement the

standards and measuring instruments of States, cities, scientific

laboratories, educational institutions, or the public, for which a nominal fee is charged, except in the case of the National and State

Government institutions. It is at all times glad to assist these institutions in matters concerning these standards or their use, whether

it be m connection with the enactment of laws, regulations, or ordinances concerning the weights and measures of everyday trade

or in connection with precision standards used in scientific work.
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, particuI larly 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 man1 ufacturers ; they are fundamentally concerned, either directly or

j indirectly, with the improvement of methods of production or the

quality of the output. It may be said that the Bureau occupies somewhat the same position with respect to the manufacturing interests

of this country that the bureaus of the Department of Agriculture

i do to the agricultural interests. Many industries realize the importance of scientific investigation which, in practically every 'case,

involve some kind of precision measurement.

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

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

I of exact methods and scientific results is the greatest factor in the

I improvement of quality, efficiency, or the development of new industries. The educational value of the Bureau's work in this respect

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

' receives hundreds of letters, as well as many personal visits, from
22 KEPORT OF DIRECTOE 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, Avhich is in charge of the standards and inspection service of the trade weights and measures; also the National

Physical Laboratory, whose functions include matters pertaining to

scientific and technical standards, phj'sical 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 Physikaiisch-Technische

Eeichsanstalt, 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 generall}' recognized that

these institutions have been exceedingly important factors in the

industrial progress of these countries.

The Collection of Fundamental Data for the Industries.

During the past ^^ear'^the Bureau has continued its close cooperation with American industries. Eecentl}' a large number of 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 con- cerning 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.

Simplification of Standards.

An extremely important matter in which the Bureau is interested

is the simplification of industrial products through the elimination

of useless sizes, unnecessary variations in the composition of materials intended for the same purpose, and the removal of unprofitable

restrictions upon output through poorly prepared or obsolete specifications. The small sum necessary to carry on work in connection

with simplification of this sort will be returned manyfold in the increased efficiency of the industries benefited.

To illustrate the need of this work, it is only necessary to consider

that in the majority of our industries many sizes and styles of material and devices have come into use, not through any real demand
REPORT OF DIRECTOR OF BUREAU OF STANDARDS, 23 •

for such a variety of equipment but through the undirected natural

expansion of the business. The keeping of so many sizes and styles in

stock is a source of unnecessary expense. Several investigations

recently conducted by the Bureau have shown that large sums of

money can be saved in several of our manufacturing industries by

simplification of this sort. Such standardization can best be car- ried out by an unbiased third party working in cooperation with

manufacturers and visers. This fact is generally recognized by the

industries, which are only too willing to cooperate in every way

possible.

Elimination of Industrial Wastes.

In cooperation with the industries of the country the Bureau is assisting in the great problem of the elimination of industrial wastes,

which, like all major problems, depends for its solution upon cor- rect fundamental scientific and technical data. For many years the

Bureau has kept in touch with industrial processes and has acted

as a clearing house for certain kinds of information concerning

improvements in methods of production. It has assisted in the preparation of specifications, codes, and ordnances, all having for their

primary object the increasing of industrial efficiency. Through its

researches ways and means have been found for the better utilization

of our raw materials, for cheapening and improving the quality

of manufactured articles, and for turning to useful purposes the byproducts of industrial plants. A long list of investigations directly

bearing on this subject, which are now in progress in the Bureau's

laboratories, might be cited, but it is only necessary to state that

along each one of these lines great savings are possible, compared to

which the small sums expended for the necessary research work are

insignificant.

It is worth while to mention in this connection that the Bureau's

position in the industrial field is such that any suggestions which it makes concerning methods for increasing efficiency are always well

received.

Training of Experts in Various Industrial Fields.

One of the greatest services which the Bureau perforins for the industries is the training of men for scientific and technical research

work. Many young men receive what is, in some respects, better than

a postgraduate course by working in some of the minor scientific positions at the Bureau during the 3'ears immediately following the

completion of their college course. These men then go into the industries with a better conception of the problems of research work.

In this connection it should be mentioned that while the entrance

salaries in these lower-grade positions are perhaps sufficient those

paid the more experienced members of the scientific staff are wholly

inadequate. This has resulted in the present difficulty of retaining

the most valuable men in the Government service. It is assumed that

as soon as possible this unsatisfactory condition will be remedied and

the salaries of these experts placed more on a plane with the compensation for similar work in industrial and even educational institutions. Unless steps are taken to meet this situation it will be impossible to maintain the Bureau's staff on the high plane of efficiency

which it has always occupied.
.24 REPOET OF DIRECTOR OF BUREAU OF STANDARDS.

4. RELATION OF THE BUREAU'S WORK TO THE

GOVERNMENT.

Comparison of Standards of Other Government Departments with

Those of the Bureau.

The use of exact standards enters into every branch of the Government service, as it does into every industry and into the everyday life

of all persons. It was in the Government service, however, that the

need for exact standards was first appreciated. The -vyork done for

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

Many bureaus of the Government service are charged with the

administration of laws and the establishment of regulations, the intelligent 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 Bureau's

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

source of misunderstanding and litigation between the Government

service and the public. Conspicuous examples of bureaus to which

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 econotny, 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 Goveriunent service in its

structural work. This information is necessary to the public in

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

its findings available to the public generally. The demands for information 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 Architect, the engineering branches of the Army, the Bureau of Construction and Repair of the Navy, the Panama Canal, and the Reclamation 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
BEPOKT OF DIRECTOR OF BUREAU OF STANDARDS. 25

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

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

other branches of the Government.

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

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

cases substantial help has been rendered to the military and civil

departments through the familiarity of the Bureau with certain kinds

of work and its ability to quickly decide whether the particular

methods, materials, or devices were suitable for the service in question.

The Bureau as a Testing Laboratory and Its Work in the Preparation of Specifications on Which to Base the Purchase o£

Materials.

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

departments of the Government when called upon; and, as such, is

assisting to place Government purchases upon an economical and

businesslike basis. The example of the Government in such matters

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

than to place its own purchases upon a basis which may be taken as a standard by the public at large. This work involves the specification of a wide range of structural and miscellaneous materials and

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

materials are purchased by means of competitive bids, a method

resulting in much fraud and injustice unless suitable standards are

established and successful bidders held absolutely to this standard in,

malring deliveries. Furthermore, most purchasing officers are realizing the great importance of having such testing done by a disinterested institution equipped with the scientific and other facilities forperforming 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 Avide 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 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
26 REPORT or DIRECTOR OF BUREAU OE STANDARDS.

upon the classes 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 pevtaining to quality or performance where heat measurement is the

essential and predominating factor.

Similarly, the Electrical Division is concerned with all the electrical problems that jnaj be taken up at the Bureau, whether in con- nection with the various electrical standards of measurement, electrical 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.

Practicalh/ all investigations concerning the various classes of

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

many chemical standards and questions which arise in connection

with chemical work generally, especially in the industries. Hence,

there is a Chemical Division, cooperating with every other division

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

chemical nature that come to the Bureau and Avhich 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 involved 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

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, aeronavitic 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.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 27

Tlie Ceramic Division is concerned with all problems in connection

Tvith the use of clays and clay products, with investigations in the

field of glass manufacture, and with questions involving the use of

refractory materials and enameled metals.

The employees engaged in clerical work, 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 35 acres in the northwest section of Washington,

on Pierce Mill Eoad, 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

increased by the location of the laboratories in a section free from the

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

I. WEIGHTS AND MEASURES.

The Division of Weights and Measures is concerned with measurements involving the fundamental 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, gauges, and screw threads ; cooperation with States

in the preparation and enforcement of weights and measures legislation; the design,

improvement, and inspection of weights and measures apparatus, the carrying out of researches designed to result in more accurate knowledge of physical constants and

improvements in engineering practice.

GENERAL.

The Importance of Weights and Measures.

The importance of weights and measures in our every-day life will

be appreciated only when consideration is given to the many points

at which we come in contact with them. Practically everything with

which we deal is at some time or other either weighed or measured,

and the correctness of our judgement of relative values is dependent

largely upon the accuracy of this weight or measure. The price and

value of our food, clothing, shelter, fuel, the nicety of fit and adjustment and proper functioning of mechanical products, are all directly or indirectly dependent upon accurate comparative measurements.

In fact, all advancement in science, industry, engineering, in civilization itself, is linked with advancement in the art of weighing and

measuring.

LENGTH.

Investigations in Precision Length Measurement.

A great deal of time and study have been given to precision length

measurements during the year, and the time spent in routine work

on the many miscellaneous applications of length measurements

which the laboratory has to handle has, by improved methods,- been

reduced almost to a minimum. The time thus saved has been concentrated on the working out of several problems connected with precision length measurements—in improving the meter comparator, in

getting the constant temperature room with its thermostatic control

into better condition, in working on problems of best illuminaion of

bars with the least amount of heating, with precise focusing, particularly with respect to fine lines which are not properly cut, and in

studying the character of the lines. The sources of some apparent

discrepanices in length measurements have been thus found and a more exact knowledge of the comparator has been gained, so that

conditions can more easily be duplicated and, therefore, it is now

possible to check more accurately than heretofore by intercomparison

the relative values of the platinum-iridium meters. All of these,

except meter 27, the fundamental standard of length of the United

States, have been intercompared and calibrated, as well as several of

the less important ones.

28
EEPOKT OF DIRECTOR OF BUREAU OF STANDARDS. 2-9

This investigation of precision measurements by means of the

Bureau's comparator, besides giving more reliable information about

the present constants of working apparatus, will serve as the preliminary work in the investigation of length measurements by means

of the interferometer, a problem which universities and manufacturers are looking to the Bureau to solve and which, on account of

its importance, must soon be taken up.

The micrometer microscope is an invaluable instrument in precision measurements, so in this connection one member of the section

has undertaken a much-needed investigation of the errors of micrometer-microscope screws. A considerable number of difficulties have

been surmounted and results of value to the work of the section have

been produced, though only a beginning has been made -in the work

to be done. Making use of the results obtained from these investigations the Bureau was able to calibrate length standards with a higher average accuracy than before.

There is still a field for much additional work on the Bureau's

length standards. For example, the temperature coefficients of the

platinum-iridium meter bars should be more accurately redetermined,

more work should be done on the problem of proper illumination of

lines, and meter number 27, the fundamental standard of the country,

should be recompared at the International Bureau.

Status of Standards.

The present status of the section's apparatus and standards is the

"best that it has been for many years. Eecent calibrations, some of

which have been mentioned in the preceding paragraph, have yielded

important data on the numerical constants and corrections for a large

proportion of the equipment. The results in a number of cases have

given proof of the need of constant intercomparisons and checking

of standards.

Further improvements to be made in the geodetic comparator and

the meter comparator will make these of still more service and will

also result in increased accuracy. Attention to one or two details

and an improved method of moving the microscope on the bench will

further improve the apparatus.

Eeference to last year's report shows that three instruments were

urgently needed: (a) Comparator for calibrating the intervals of a graduated standard; (&) a small comparator for calibrating sieves

and small scales, etc.; (c) projection apparatus for testing sieves.

The need of all three still exists, but that for the first is the greatest.

There is at present but one piece of apparatus in the Bureau for

-calibrating the intervals of a graduated linear standard of precision,

and that is the dividing engine. This, however, is in use practically

all of the time on the work for which it was designed and is further

limited by the fact that a 1-meter scale can not be calibrated with

precision to decimeters on it. This is a condition which should be

remedied.

Routine Testing.

As mentioned in a previous paragraph, the time spent on routine

testing has been reduced practically to a minimum by improved

methods. For example, the improved method of testing and sealing

lisemacytometers in lots of about 25 each, it is estimated, takes about
30 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

one-eighth of the time required three years ago. The results are

fully as dependable and the probability of damage to the chamber

^ or to the cover glasses is reduced. Sieves are now tested in about

half the time in which the work was formerly done.

The following ai'ticles were tested during the year: Twentj^-six

length standards and precision scales (yard and meter bars, etc.) ; 200 tapes (steel, invar, and " reinforced " cloth) ; 250 sieves; 8 pieces

of sieve cloth; 317 hcwnacytometers (blood-counting chambers) ; 489

extra cover glasses for hsemacytometers ; 25 level rods; 1 length

comparator for gauges, complete; 49 miscellaneous articles tested

for length or angle.

The length standards include those of three manufacturers of

length-measuring apparatus, that of a foreign Government, and

several from State governments. The manufacturers' standards were

all calibrated throughout. This, together with the standardization

of the Bureau's own apparatus, which is not included above, represents an unusually large amount of work.

The tapes include all varieties, from the precision base-line tapes

of the Coast and Geodetic Survey and precision wires of the Department of Geodesy of the Mexican Government to several " reinforced " cloth tapes used by the Department of Commerce for approximate measurements of the holds of ships.

Sieves have been submitted in very large numbers during the past

year. The regrettable fact, however, is the lai'ge number which have

been exceedingly close to the allowable limits in one particular or another rather than close to nominal value.

Indications in the hsemacytometer field are that certified chambers

have become quite widely purchased now and present tests are largely

for replacements. It is expected that there will be another revival

of this work at the time the medical schools open in the fall. A new

type of chamber has been submitted to the Bureau in which the

glass slide, the ruling surface, and the cover glass supporting surface

are of one piece of glass, a decided advance in construction.

A universal comparator built by the Societe Genevoise for the

measurement of gauges and end standards was completely tested and

inspected. The several scales, micrometer screws, and other lengthindicating devices on the instrument were calibrated.

Visitors and Travel.

Besides the more or less casual visitors in the section there have

been representatives of a number of concerns making or selling instruments or articles tested in this laboratory also several experts

in lines of work very similar to that in this section.

A member of the length section spent a week at Ottawa, Canada,-

conferring with experts there regarding methods of precision length

measurements.

MASS.

Tests.

There were over 6,000 weights tested during the year, an increase

of about 14 per cent over the number tested last year. Of these 67

per cent were for private individuals or firms, 23 per cent were for

the Federal Government (including tests for other sections of this

Bureau), 5 per cent were for State governments, and 5 per cent for

educational institutions. Ninety per cent of the weights were in
KEPOKT OF DIRECTOR OF BUREAU OF STANDARDS. 31

high-grade analytical sets, such as are commonly used in physical

and chemical laboratories. The testing of this class of weights was

kep.t very closely up to date, there being no long delays in any case.

Rejections.

About 3 per cent of the weights submitted were rejected on inspection for special faults of construction or for failure to conform in

some particular to the specifications of the Bureau, and about 10

per cent for inaccuracy. The situation is much worse than this would

seem to indicate, however, because the large majority of the weights

are submitted in sets, and since each set is handled as a unit the loss

caused by retesting the sets after they have been corrected is very

great. As a result makers have raised the price of weights intended

for certification, and there have been requests both for the addition

of a new class of a lower grade and for a return to the practice of

allowing makers to replace individual weights of a set while they are

at the Bureau being tested.

The delays and uncertainties involved in procuring certified

weights under present conditions are very serious, and some method

of avoiding them would, be a benefit not only to the maker and dealer,

but also to the users of such weights.

Standards Tested for the States and for Manufacturers.

Standards were tested for the States of Massachusetts, Vermont,

West Virginia, and Texas. A set of primary standards was also

tested for one of the newer manufacturers of laboratory weights.

Assistance to the Motor Transport Corps.

A large number of weighings have been made to help determine the

amount of wear on parts of automobile truck transmissions being

tested by the Motor Transport Corps. In a few cases the wear has

been masked by some other change, but in the majority of cases the

weighings have proved a valuable addition to the measurement of

dimensions.

Shortening the Work on High Precision Tests.

A careful study was made of the precision required in the auxiliary

observations needed in testing the higher precision laboratory

weights. Limits were set as to the permissible range of temperature,

humidity, and barometric pressure, and so long as the observations

are made within these limits all corrections for the buoyancy of the

air can be omitted from the individual weighings and from the

customary computations of results, a proper correction being applied

to the final value of each weight. Since the work can generally be

done within these limits, the work of computing these tests will be

very much reduced. A new form of record sheet has been designed

for this part of the work which will also help materially to put this

testing on a more systematic and efficient basis.

Changes in Weight of Celluloids.

An investigation of the effect of atmospheric humidity on the

weight of pyroxalin plastics from three different manufacturers was

completed during the year. Weighings of specimens were made at

three or four different humidities in a box in which the relative
32 KEPOBT OF DIRECTOR OF BUREAU OF STANDARDS.

humidity could be maintained at any desired value. The following

facts were noted

1. All samples showed a loss of weight with age which gradually

became slower and which was practically independent of the

humidity.

2. There were no appreciable differences in the behavior of " transj)arent," " ivory," " cream," and " red " samples nor in the samples

from the three different makers.

3. The changes in humidity did not cause any permanent change

in the samples; the weight rose and fell with the humidity in all cases.

4. The changes were not mere surface effects. The water vapor

evidently penetrates into the interior of the sample, so that thick

samples continue to gain or lose long after thin samples have reached

equilibrium.

5. The change in weight is not proportional to the relative humidity, but is much greater at high humidities than at low humidities

for the same change in relative humidity.

' 6. The total observed changes in weight were a little over 2 per

cent for a humidity range of about 30 per cent to 95 per cent.

Standards and Apparatus.

Three of the precision balances were overhauled and readjusted

in essential details. The work of overhauling and mounting the

highest precision kilogram balance was continued as opportunity

could be secured. Fortunately, the pier on which the balance rests

is so well isolated that it is apparently free from vibrations, but this

was not the case with the mounting for the reading device. After

trying many kinds of mountings for the telescope one which gave

the desired freedom from vibration and yet maintained a satisfactorily constant zero point was developed and installed.

Further work and tests are still needed before the balance can be

relied upon for the character of work for which it is intended. In

the meantime the older balance is being used and is sufficiently

accurate for the work so far required of it. The apparatus for

rapid testing of 50-iDound test weights was nearly completed by the

instrument shop.

Recommendations.

The most important need for next year is, as last year, the work

on the primary standards. It is recommended that the set of platinum-iridium weights from 500 grams down be calibrated at once,

and that the older set of gold-plated weights from 1 kilogram to 1

gram be replated and redetermined.

Careful studies as to the accuracy needed in the measurement of

barometric pressure have shown that a much more accurate barometer is needed, and it is recommended that a high precision normal

barometer be either bought or built. Studies as to the best form of

instrument have already been begun, since it is probable that to secure the highest accuracy it Avill be necessary to design and build

the instrument at the Bureau.

TIME.

Investigation of Stop Watches.

On account of the unsatisfactory service which has been obtained in

scientific work from stop watches purchased by the Bureau, an
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 33

attempt has been made to determine whether the trouble is due to

faulty purchase specifications or to poorly designed instruments.

As a result of this investigation it has been decided that certain types

and models of stop watches are poorly designed and constructed by

their respective manufacturers. The specifications have not been

changed, but there has been prepared a list of types or models tentatively approved for purchase by the Bureau. This list does not represent the ideal, but merely the best obtainable at this time. Considerable improvement of stop watches is highly desirable for scientific

work.

Drum Chronographs.

The drum chronographs which have been supplied the Bureau and

used in measuring short-time intervals were unsatisfactory in design.

There has recently been located a new source of supply which, it is believed, will answer all requirements.

Advisory Work,

Representatives of the Bureau attended a conference vinder the

auspices of the National Research Council for the horological interests

of the country. The purpose of this conference was to discuss

methods of overcoming the increasing shortage of watch repairmen

which exists throughout the country. The lack of repairmen has

resulted in a larger demand for new watches than can be met by the

factories. Furthermore, men have left the factories to work in the

local shops. As a means of overcoming the scarcity of watch repairmen the industry is planning to have the men certified into various

grades. The assistance of the Bureau is contemplated for accomplishing this purpose.

Improvements in Equipment.

A new switchboard was installed for the purpose of distributing

either make-circuit or break-circuit signals for use in the laboratories

throughout the Bureau, as other sections of the Bureau use the timesignal system of this section extensively.

The Riefler clock, which serves as the precise time standard, was

cleaned and oiled and is now performing with its usual high precision, the error being only about 0.01 second per day.

An. additional thermostat for maintaining constant temperature in one of the testing cabinets was made and installed.

Routine Testing.

The section has completed the following routine tests

Class A watches 13

Railroad precision watches 204

Ship watches 454

Comparing watches 23

Stop watches 33

Wrist watches (submitted by War Department) 6,109

Chronometei's 2

Miscellaneous 3

Total 6,841

64984—21 3
34 REPOBT OF DIRECTOR OF BUREAU OF STAKDARDS,

Future Work.

There is so much material aAvaiting test that it will fully occupy

the time of the entire personnel of the section for a number of months

without taking into consideration the additional work which may

be expected. Much of this, as heretofore, is for other branches of

the Federal service and is highly desirable from the standpoint of

public economy.

There are three additional inve^igational problems to which it

is desired to call special attention, one is relative to the magnetism

of watches, a problem which is always before the trade. The seat

of magnetic trouble in watches, and the relation of the magnetizing

field to performance of the watches, is unknown. This problem, if

undertaken, would necessitate a joint investigation with the Electrical Division.

A problem originated by the Electrical Division and suggested for

a joint investigation is the development of an electrically operated

clock which does not have an escapement or friction bearing. This

investigation offers the possibility of producing a timepiece of unusual precision.

A third problem worthy of being prosecuted is in connection with

the new alloy called " elinvar." This alloy has a negligible change

of elasticity with temperature and is reported as being suitable for

the manufacture of watch hairsprings to be used in connection with

solid balance wheels and as producing results superior to those obtained from compensated balances. If a suitable method of application of this alloy can be developed, it will be of material benefit to

the general public.

Additional Equipment.

Two additional pieces of equipment are needed. There is great

need over the Bureau for a reliable time signal with a signal interval

of only a small fraction of a second to supplement the two existing

signals of one second and one minute. The other piece of equipment

which is needed is a radio receiver for the chronographic registration

of radio time signals. This instrument has already been developed

by another section of the Bureau. The only expense will be the actual

cost of construction and installation.

CAPACITY AND DENSITY.

Research.

An investigation has been carried out on the density of steel and

iron under different conditions of manufacture for the Metallurgical

Division of the Bureau, the data as obtained being used in some of the

work done by that division. Several samples of platinum were ex- amined for density in connection with researches conducted by the

Chemistry Division on that metal. This had to do with the purity

of the sample and the freedom from entrapped air in the ingot. In

some of the work the purity was known and the density was used

as the means of indicating the freedom from blowholes, while in

other cases the density was an index of the purity of the sample, the

ingots having been so cast as to be free from included gases.

There is need for additional work on American petroleum oils in

order that the tables in Circular No. 67 may be extended to cover a
REPORT or DIRECTOR OF BUREAU OF STAN^DARDS. 35

wider range of density and temperature. Sufficient oil samples are on hand to continue this work, but at present the large amount of

routine testing makes it impossible to devote a great amount of time

to research without falling seriously behind in the routine testing.

Many requests were received during the year for the density and

pounds i^er gallon of various vegetable and other oils. A publication

giving these data would be very useful. The preparation of such a

publication will require the determination of the density of representative samples of these materials. This Avork will be carried on

as opportunity permits.

Testing.

The following is a report of the testing done by the volumetric

section for the year ended June 30, 1921;

Apparatus.

Number

sub- mitted.

Number

tested.

Per cent

of total tested.

Number

passed.

Per cent

of total passed.

Burettes 1, 323

378

3

1,501 3,734

3,202 201

820

308

2 1,477 3,056 2,163

98

62

8267

98

8168

49

566

72

1 1,273 2,790

1,54190

4319

3385

7448

45

Cylindrical graduates Cone graduates

Dilution pipettes Flasks

Pioettes, transfer Pipettes, measuring

Hydrometers

10, 342 7,924 77 «,333 j 61

628 619

161

55

1149

1111

145

99 427 68 Caoacity measures, intluding Dover and Seraphin

measuring cans Density determinations

Special api aratus:

Sneoifio gravity flasks Miscelaneous. ." 1

An examination of the above data shows that of the volumetric

apparatus submitted for test 77 per cent was eligible for test, 23 per

cent being rejected upon preliminary examination. The major portion of the rejections in the case of flasks was clue to unsatisfactory

blanks having striae and bubbles and to lack of stability due to imI^roper design. Burettes in a few cases in which large shipments

were made were very unsatisfactory as to workmanship, and a large

number of leaky stopcocks were found during the year.

Sixty-one per cent of the glassware submitted passed the test, and

of that actually tested 80 per cent passed the test. This is better by

2 per cent than the record of the previous year.

Of the hydrometers submitted 68 per cent passed the test, 1 per

cent was rejected on preliminary examination, and the remaining 31

per cent had errors in excess of the tolerance allowed. In these cases reports were issued showing the errors found, thus making it possible to secure accurate results with these hydrometers by applying

the corrections.

A comparison of the data given in this repo*t with those given last

year shows that there was an increase of 54 per cent in the number of

pieces of glass volumetric apparatus submitted for test and of 47 per

cent in the number of pieces that passed the test.
36 KEPOET OF DIRECTOR OF BUREAU OP STANDARDS.

The number of hydrometers submitted shows a loss of 8 per cent.

This decrease is accounted for by the fact that the Bureau of Internal

Eevenue no longer submits alcoholometers for test. There were 502 Bureau of Standards numbers assigned to hydrometers. This is an increase of 15 per cent over the previous year. The

time required to test hydrometers is materially increased when such

numbers are assigned. Also, the instruments tested during the year

were mainly on small orders and were usually of different ranges and

types. It is gratifying to know that the trade is coming to appreciate the value of certified instruments.

The apparatus on hand awaiting test includes 811 flasks, 677

burettes and measuring pipettes, 1,356 transfer pipettes, 297 cylindrical graduates, 6 specific-gravity flasks, and 8 special pieces, a total

of 3,155 against a total of 2,451 a year ago. With our present force

and equipment it will require 8 to 10 weeks to complete the testing

and forwarding of the stock on hand. There are also on hand a few

hydrometers, dilution pipettes, and capacity measures.

Visitors.

There Avas an unusually large niimber of visitors, representing

various firms who make glassware. They came in the interest of improving precision apparatus, and, judging from the subsequent improvements made in the quality of apparatus sent for test, they

received information very useful to them.

A very great ser^dce can be rendered the makers of apparatus

through conferences with their representatives at the Bureau. This

institution is likewise benefited by these visitors, especially if they

go away feeling that the Bureau has the desire, the equipment, and

the personnel to help them in their work.

Additional Space Needed.

If the glass volumetric apparatus submitted continues to increase

more laboratory room will be necessary. There is at present sufficient

help for the laboratory space allotted to this section.

GAS MEASUREMENT.

Field Work.

Sixty-seven meters were tested for the Fort Worth Gas Co., Fort

Worth, Tex., and a member of the gas measurement section observed

and supervised the test of about 40 additional consumers' meters.

This work was done in the settlement of a controversy between the

gas company and the city of Fort Worth.

During the month of June. 1921, two members of the gas section

were engaged in an extended test of so-called town border meters

for the Lone Star Gas Co., Dallas, Tex. This work is still in

progress, and a complete report can not, therefore, be rendered, at this time. Judging, however, from the Avork so far done and from

the results of a similar investigation carried out about two and a half years ago, it appears that a A^ery great saving may be effected

by the location and stoppage of leaks betAveen the town border and

consumers' meters. The former investigation showec^ an annual

loss of natural gas amounting to some $4,000,000.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 37

A member of the section has spent several weeks during the year

at Trenton, N. J., in testing meters and related equipment for

use of the Chemistry Division of the Bureau in carrying on a

cooperative investigation of methods for the generation of hydrogen.

Research and Preparation of Tables.

The section has assisted the cement section of the Bureau in designing apparatus for measuring the volume of air supplied to an

air separator used in grading fine particles of Portland cement.

An investigation was made of the differences of calibration of wet

and dry meters with different gases. No consistent differences

attributable to the use of different gases were observed.

Attention has been given to the calculation of tables of equivalent pressures and volume-reduction factors for use in meter testing.

Also, some measurements have been made to determine the temperature differences between meter and meter prover under various conditions of test.

Routine Testing of Gas Meters.

Twenty-one meters of various types Avere tested in the laboratory

during the year. This service was performed for departments of

the United States Government, the Philippine Government, public

service commissions, and private corporations.

EXPANSIVITY OF SOLIDS.

Research, Investigation, and Tests.

Data have been taken on all important terra cottas now being used

throughout the United States. Similar data have been secured on

underslips and glazes. This work is now ready for coordination and

publication and will furnish valuable information for the terra-cotta

manufacturers in their attempt to improve this material. In carrying on this work the Bureau was assisted by cooperation from the

American Terra Cotta Societ3^

Results of tests on enamels made for the Ceramic Division are being tried out on a commercial scale at different enameling plants.

The preliminary reports are encouraging and justify the conchisions

previously reported that " fish scaling " of enamel ware is largely

influenced by the relative expansions of enamels and stock. An

abstract of this research will appear in the August issue of the

Journal of the American Ceramic Society. This is to be followed by

a Bureau publication.

The work being done on a series of 20 machine-gun steels has

been completed. All specimens were carried above the transformation points and numerous observations taken during the passage

through these points. This information is now being prepared for

publication. This is, perhaps, the first work of this accuracy which

extends over a temperature range from room temperatui^e to 925° C.

In addition to these special steels there have been examined a number

of ordinary steels and irons, and this combined information Avill give a rather comprehensive paper on the subject. In all there were

244 expansivity tests made during the year.
38 EEPORT OF DIRECTOR OF BUREAU OF STANDARDS.

The demand for a steel of low expansion has been great and is

increasing, and the Bureau has been able to secure the cooperation of one of the steel manufacturers in producing this material. Some

specimens have been produced which have lower expansion than

much of the so-called invar. An attempt is now being made to get

similar cooperation in the production of " elinvar " or some similar

alloy of constant elasticity, a supply of which would greatly benefit

certain industries.

The Bureau's report on the physical properties of dental amalgams

has been well received by the societies and profession. Many inquiries and personal visits are being received concerning assistance

on this and other phases of dental procedure. Preparations are being made to carry out a similar investigation on the properties of

inlays and inlay investment materials. These researches are appropriate because of the number of defective restorations that are being put in by conscientious men.

Travel.

A representative of the Bureau was invited to address several

dental societies and report on the Bureau's investigation of the

physical propei^ties of dental amalgams. The profession is very appreciative of this work.

Improvement of Equipment.

The equipment for thermal expansion has been impi-oved decidedly

by the addition of a platinum-rhodium gold thermocouple, a selecting

switch free from thermal electromotive force, and lead-sheathed

cables for potentiometer leads.

Work has been started on the problem of cutting precision screws. There are demands for line length standards with smaller errors than

those now in use, and foreign laboratories have not been able to re- duce the limit of errors in these supplies. A screw of higher precision

is likewise in demand and could be used in ruling gratings. The

findings to date demonstrate the necessity of securing or treating

steel for permanence of dimension. The errors of gears and other

periodic errors are readily detected and means are being provided

for their elimination. This problem will of necessity continue over an extended period, since it is desirable to work out details relating

to bearings, gears, lapping, ways, carriage, lines, etc.. The gauge section was requested to make up some polished steel

surfaces for the line-ruling experiments. After malring several at- tempts they were highly successful in producing hardened steel sur- faces of a polish such that no scratches or defects were discernible

with magnifications of 2,500 diameters. These surfaces have made it possible to develop the desirable characteristics of lines until lines

considerably narrower than 1 micron can now be cut, the entire set of lines being highly uniform in width and shape of cut. Some of the rulings were electroplated with nickel by the Chemistry Division and exact replicas were secured. In fact, no defects are discernible when using the highest magnifications. A further

observation indicated that these nickel surfaces which have been

electroplated to steel are of higher polish than it is possible to secure when polishing nickel directly.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 39

COMMERCIAL SCALES.

Investigation of Railroad Track 'Scales.

The railroad track scale-testing equipments Nos. 1 and 2 of the

Bureau of Standards consist of box cars carrying 90,000 pounds of

standard weights in 10,000-pound, 2,500-pound, and 50-pound units,

together with a truck weighing 5,000 pounds, upon which the weights

ean be loaded, equipped with an electric motor, so that it can be

moved across the scale platform during a test. The test car is

equipped with a gasoline engine, a dynamo, an electric crane, and

other machinery and equipment for the unloading and loading of

the truck and weights. Test car No. 1 has been in hard service since

1913 and No. 2 since 1915. At the beginning of the year it was

found that equipment No. 1 would require very considerable repairs

to the car body and equipment and replacements of worn out parts

if it were to be kept in serA-ice, and equipment No. 2 was also badly

in need of overhauling. Therefore during this yesLT both cars have

been laid up from time to time, and this work has been done partly

by the personnel operating the cars and partly in railroad shops

under the supervision of the Bureau's field force. This has necessarily resulted in considerable interruption to the testing schedule and

unusually heavy expense connected with the work. In fact, during

the latter part of the fiscal year lack of funds rendered necessary the

laying up of the equipments during a large portion of the time. The

master-scale schedule for the fiscal j^^ear 1921 which normally would

have been completed during the calendar year 1920 was not completed

imtil June, 1921, and the new schedule will be arranged to start in

July of this year when funds will again be available. Both of the

equipments mentioned above are now in good mechanical condition,

and they can doubtless be kept in efficient service for some years to come. During the year tests were made in 24 States and the District of

Columbia, as follows: Arizona, California, Colorado, Connecticut,

District of Columbia, Kansas, Illinois, Indiana, Iowa, Maryland,

Massachusetts, Minnesota, Nebraska, Nevada, New Hampshire, New

Jersey, New York, North Carolina, Ohio, Pennsylvania, Rhode

Island, South Carolina, Utah, Virginia, and Wisconsin.

A resume of the tests made, except master-scale tests, is given in

the following table:

Scales tested. Number.

Correct. Incorrect.

Number. Per cent. Number. Percent.

Railroad-owned track scales Industrv-owned track scales Go/ernfnent-owiied track scales

Total

245

29

8

132

17

1

53.9

58.6

12.5

US'

12

7

46.1 41.4

87.5

282 150 53.2 132 46.8

The same tolerance is allowed as in the past, namely, 0.2 per cent, or

200 pounds per 100,000 load, this tolerance also having been adopted

by the American Eailroad Association and recommended by it to its

members. The percentage of correct railroad-owned scales, 53.9

per cent, is about 10 per cent higher than last year, and the per-
40 REPORT OF DIRECTOR OP BUREAU OF STANDARDS.

centage of correct industry-owned track scales, 58.6 per cent, is about

20 per cent higher than last year. 'The correctness of Gorernmentowned track scales is still very low.

The errors of track scales found incorrect varied from 0.21 per

cent to 3.8 per cent, the average numerical error being 0.6 per cent.

This excludes the error on one scale, which was subject to such deflection of parts under a 90,000-pound sectional load that the bridge

rested on one of the levers, resulting in an error of 33 per cent.

Testing and Calibration of Master Scales.

For some years prior to the Avar and since the railways were turned

back to private control the Bureau has had an agreement with the

American Eailway Association by the terms of which the Bureau

maintains the standard of weight on the various lines of the country

by testing all master scales once in each year and by making adjustments when needed and when by this means they can be brought

within the established tolerances. The Bureau is convinced that this

service is very necessary if the condition of the track scales in general

use is to be maintained and improved, since these master scales are used in calibrating the test cars owned and operated by many of the

railroads for testing their weighing equipment. Were the master

scale to be incorrect, its error would be transmitted through the test cars to all the commercial scales tested and adjusted by them. The

Bureau's equipments 1 and 2 are especially suited to the test of master

scales, since they bring to these scales a sufficient amount of standard

weights of known accuracy. No other equipments in the United

States are suitable for such service. While traveling on the prearranged master-scale schedules the Bureau's equipments are moved

by the various railroads free of charge. The agreement contemplates

that the master scales will be tested once in each year, but this year,

on account of delaj^s previously described, the schedule intended to

be completed December 31, 1920, was not finished until June, 1921.

The master scales are located in various States, from North Carolina

and Pennsylvania in the East to California in the West, and thus

a very great amount of territory must be covered each year. Fourteen master scales owned by railroads, industries, and one State were

tested.

The Bureau is pleased to report that new master scales have recentl}^ been installed and others are about to be installed, some

being at new points and others are replacing some of those Avhich

have been reported by the Bureau in the past as unsatisfactory

scales for the purpose.

Bureau of Standards' Master-Track Scale.

In 1916 the Bureau entered into a contract with a manufacturer to

build a master-track scale for the Bureau, such a scale being even

then urgently needed. The scale was built according to an advanced

design which the Bureau and the manufacturer jointly developed,

and it is probably the best master scale which has been constructed

up to this time. The scale was completed several years ago, but

unfortunately up to the present time funds have not been available

for providing a centrally located test depot in which to house this

scale. As a result the Bureau has been imable to realize upon its

investment, although the scale is very urgently needed in the cur-
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 41

rent track-scale work, and without it this work must always be

very greatly hampered. Track-seale testing equipment No. 3 comprises test cars Nos. 3 and 4, these being 40,000 and 80,000 pound

self-contained test vinits traveling on their own wheels. Therefore

they must be reAveighted at intervals not exceeding two months 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 (including the special trucks)

carried on cars Xos. 1 and 2. which are used in certifjdng to the

accurac}'^ of every master scale in the United States, must be re- painted and adjusted from time to time and the equipments over- hauled. The Bureau has no present facilities for doing work of

this character.

As pointed out last year, in addition to the needs of the Bureau

the proposed testing 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, pei'haps. than any other 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 biisiness 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.

Mine-Scale Investigation.

The investigation of the condition of mine scales, used to determine

the weight of the coal mined by the individual miners, and thus to

ascertain the wages of the workers, was prosecuted as actively as was

found possible. Experience in the past having demonstrated that

it was impractical to attempt to operate the Bureau's equipments

continuously throughout the year on the funds provided, it was decided this year not to attempt to operate both track-scale equipments and mine-scale equipments at the same time, since by so doing

too large a field force would have to be employed. Consequently, as the need arose field men from the railroad-scale force were transferred to the mine-scale work, which latter was not actively prosecuted until spring. As a result excessive turnovers in personnel were

avoided, and it was not required to train men in the work with the

probable necessity of dispensing with their services after a short

period, and thus efficiency was promoted.

The mine-scale work Avas carried on in fields not heretofore visited,

Indiana and Illinois receiving special attention. A resume of the

scales tested is given in the following table

Number. Percent.

Total scales tested. Correct Incorrect

231

o-J 177 23.4

76.6
42 EEPORT OP DIRECTOR Or BUREAU OF STANDARDS.

Magnitude of error in per cent. Number.

Per cent

of total

incorrect,

0.5 tol..

1.1 to 5.. 5.1 to 10. Over 10.

75

90

9

3

42.4

50.8

5.1

1.7

177 100.0

The tolerance allowed on this class of scales is the same as that

which has heretofore been permitted, namely, 0.4 per cent, or twice

the tolerance allowed on railroad-track scales. The percentage of

incorrect scales, 77 per cent, indicates the necessity for improA^ement of conditions, and this is emphasized hj the size of the errors encountered, 57 per cent of the incorrect scales being in error by

more than 1 per cent, and 7 per cent being in error by more than 5

per cent.

Good cooperation with the State officials in this work has been

secured, and it seems certain that the inspections being made will

have the effect of materially improving weighing conditions throughout the territories investigated. As in the past, it is found, in general, that the tests and results obtained therefrom do much to allay

suspicion, quiet unrest, and increase industriah harmony

Grain Scales.

Studies have continued on the results of tests and the detailed

character of the errors of large scales, such as grain-hopper scales.

These scales are used for weighing such large quantities of valuable

commodities that their adjustment and maintenance is a matter of

very serious importance. In this connection the Bureau responded

to a request made by the State of Kansas and conducted a test upon

a large grain-hopper scale, which was one of a number of scales of

this type installed in that State, to enable the authorities having

jurisdiction over them to determine whether or not they met certain

specifications. This test was carried on up to a load of 120,000

pounds and is probably one of the most thorough and detailed ever

carried out on a weighing mechanism of this character. Demands

for high accuracy in these scales can consistently be met only by

adjusting them with due regard to the character of their errors. Data in this work, however, accumulate slowly, as it is not often

that the situation is such that the time required for making very

detailed tests of the scales can be spared, sin^e generally such tests require that the elevator cease operation. Railroads, States, and

weighmaster's departments are cooperating with the Bureau in accu- mulating information on this subject. When the subject has reached

a point where it can be regarded as a complete investigation, the

results will be presented in the form of a publication available to all.

Quick-Weighing Scales.

Certain types of automatic dial scales are now in use in the

freight depots on a large number of railroads and in other indiistries,

and the subject of these scales received considerable study during the

past year. It appears that these devices are of very great importance

especially in facilitating the handling of freight where the movement
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 43

is heavy, as in New York City and Philadelphia, where a vast

quantity of moderate-sized shipments is handled. These scales are often used where it is difficult or impossible to provide foundations

which are desirable, and the exposure of these scales to continuous

use, to vibration, and to conditions along water fronts, where moist

air tends to corrode the scale parts, further complicates the problem. At the present time this form of scale is in very active development, and several new types are being tried out every year. The

Bureau is furthering the progress in this subject to the fullest extent

that its facilities permit.

Adjustment of Scales.

An important feature of the work in connection with the adjustment of scales has been the attempt to introduce more systematic

and scientific i^rocedure and to substitute for rule-of-thumb methods

practices based u^Don sound principles of physics and engineering.

To facilitate development along this line, a graphical computation

chart has been prepared which permits certain values required in

making the adjustments to be derived with the aid oi a pencil and

a straightedge in place of using formulas requiring arithmetical

processes for solution. It is hoped that this will render it possible

for many practical men to follow scientific principles in the adjustment of scales.

COOPERATION WITH STATES AND OTHER INTERESTS IN WEIGHTS

AND MEASURES ADMINISTRATION.

Cooperation with States.

Cooperation with the States in matters pertaining to the securing

of uniformity in weights and measures laws, rules, and regulations

and the enforcement thereof, and uniformity of specifications and

tolerances and the method of test of apparatus, thereby assisting in

obtaining a greater degree of efficiency in weights and measures work

throughout the country, has been continued during the past year. In

pursuance of this work representatives of the Bureau attended State

conferences of weights and measures officials in the States of Maine,

Massachusetts, Michigan, New Jersey, New York, and Pennsylvania.

In California a series of three district conferences and schools of instruction were held, and a representative of the Bureau attended

these and by this means was brought into direct contact with practically every State and local official in the State engaged in the en- forcement of weights and measures laws. In connection with this

trip the officials of Oregon, Washington, Idaho, Utah, and South

Dakota were also' visited and a closer cooperation with these officials

secured. This section of the country had not been visited for a number of years, and, inasmuch as only a limited number of delegates

from these States are able to attend the annual conference, the information which was disseminated and secured was of particular

value.

The Bureau also carries on this work by correspondence with the

various officials, and since a large amount of information is available

in the files of the Bureau much good is being accomplished in the

uniform solution of problems common to many of the States.
44 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Inspections, tests, and investigations upon various types of weighing and measuring devices were made in the laboratories of the

Bureau to determine whether the apparatus submitted was accurate

and wliether it complied with specifications applicable to it. Special

attention was given to liquid-measuring devices and devices intended

to be attached thereto and used in connection therewith. Many new

types are now being put upon the market and are of especial and

timely interest to those enforcing weights and measures laws. Since

the majority of the State and local depai'tments do not have laboratory facilities for carrying out investigations, the data thus obtained

are of great importance and assistance to them in their work. Reports are alwa,ys sumbitted to the manufacturers of the devices and

assist them greatly by helping them to correct and improve their

product. They are further benefited by this work because there is

secured a degree of uniformitj^ of enforcement of law which otherwise would not obtain. In general, the results are of direct benefit

to all the people, since the laws are more competently enforced, and

more reliable and accurate apparatus is constantly being put into use in commercial transactions.

Fourteenth Annual Conference on Weights and Measures.

On May 23-26, inclusive, was held the Fourteenth Annual Conference on Weights and Measures, a body composed of State and

local officials engaged in the enforcement of weights and measures

laws throughout the United States. The meeting was attended by

officials from 27 States and the District of Columbia, 21 of these

being officially represented by one or more State officials, one by an

interested person especially appointed by the governor for this purpose, and five by local officials. Eleven States had both State and

local representation, in all 106 officials being present. Fifty-nine representatives of manufacturers of weights and measures apparatus

and 32 other visitors representing railroads, weighing and inspection

bureaus, baking associations, other industries, and other Government

departments registered.

Many problems relating to weights and measures were taken up

and disposed of during the four-day meeting. Chief among these,

perhaps, was the proper method for the sale of bread. Representatives of baking associations were especially invited to attend the conference. Papers were read, followed by a full discussion. The re- sult was the recommendation to the various States for adoption of a model bread bill based upon the principle of standardization of the

weight of the loaves. Many of the States now have under consideration legislation relating to bread, and the action of the conference at this time will undoubtedly do much to secure uniformity in the

enactments on this subject. The specifications and tolerances for

liquid-measuring devices adopted last year were again subjected to

scrutiny, and some few chanffes which experience had indicated as desirable were made. Interstate weighing, testing of mine scales

and the weighing of coal, general enforrement of law, testing of commercial devices, and legislation also received attention. It is believed that the conference was among the most successful, helpful,,

and constructive of those thus far held.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 45

New Legislation.

During the 3^ear just passed Congress has not enacted any new

general weights and measures legislation, although a number of bills

were introduced, received the attention of committees, and in sev- eral cases were passed by the House. However, Congress did place

on the statute books a new weights and measures law for the District

of Columbia which is a very much better act than the one which it superseded. This legislation was based in many particulars upon

the model law recommended by the Bureau and, among other things,

it abolished the fee system of inspection, a system which this Bureau

has always strenuously opposed as being unfair, inequitable, and not

productive of efficiency, and adopted the principle of the sale of

bread in standard-weight loaves. The State of Illinois also passed

a general act. excellent in most particulars and based on the model

law. This act takes the place of a number of acts, many of which

were obsolete and ineffective. Wyoming also passed a general law

regulating commercial Aveights and measures, while Massachusetts,

Minnesota. Nebraska, Xew Jerse3\ Ohio, Pennsylvania, and South

Dakota, among others, made improvements in their present codes. In

the South, Alabama, Georgia, and Kentuclcy enacted legislation particularly relating to the weight and measure of goods in package

form.

Compilation of Weights and Measures Laws.

In the last annual report it was stated that the new compilation of

State and National Laws Concerning the Weights and Measures of

the United States was about ready for press. However, on account

of the lack of funds it has not been possible to have this work printed.

Since the compilation was made ready for the printer last fall sev- eral new State codes and compilations of State laws have been issued.

These, as well as the recent session laws, have been examined and the

mamiscript compilation has been kept well up to date.

It is very much regretted that it was found impossible to publish this work, as there is a large demand for such information.

Its early publication would be of great A^alue to the Bureau in assisting the States and local authorities in weights and measures matters.

State and local weights and measures officials would also profit by it in the prosecution of their work, as well as manufacturers and commercial interests, as it would inform them of and enable them to

comply with the A'arious weights and measures laws affecting their

products.

Cooperation with Other Government Departments.

Other departments of the Government haA'e freely consulted the

Bureau respecting scales and weighing. In seA^eral instances it was

found possible to avoid the supposed necessity for the development

and construction of new devices to meet special needs by employing

deA'ices already aA^ailable on the mai'ket which were entirely satisfactory. Many tests of scales have also been made, especially for the

War and Navy Departments. The Treasury Depai'tment, through

the Director of the ^Nlint, requested the Bureau to make an investigation of the automatic coin scales used at the mint in Philadelphia

in the weighing of all coins produced there to determine the reason
46 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

for discrepancies that had been observed in the weights of coins. A

special method of test was devised and applied, which very clearly

demonstrated the performance under service conditions of each of

the 80 beams employed and indicated what errors were to be expected

in their use. The maintenance of the standard weights of the various

coins within the tolerance prescribed by law is a matter of extreme

importance, and the Bureau is very glad to utilize its personnel and

fa(;ilities in the solution of such problems.

Cooperation with Outside Interests.

During the year the Bureau has also cooperated with many States,

manufacturers, railroads, and other agencies on matters of general

importance in connection with weighing. The Bureau has continued

to work both with the manufacturers of and those using scales in

developing specifications for various types of weighing d-evices, the

object being to assist in obtaining scales constructed in conformity

with correct and definitely established engineering principles, to

elfect economy in manufacture, with a consequent reduction in price,

by the elimination of types which are unnecessary and which can

be dispensed with without any practical disadvantages, and to in- sure specifications of such a character that those requiring scales

for certain purposes will secure scales best adapted to their needs.

In furthering this work special studies have been made to determine

the actual conditions under which scales are used, since information

of this character is very necessary if practical results are to be

secured.

Papers on scales and weighing were given before various organizations, such as the Farmers' National Grain Dealers' Association,

the National Scale Men's Association, the Weighmasters' and Scale

Men's Conference. The observance of specifications for scales which

had been prepared in connection Avith loss and damage claims in a case before the Interstate Commerce Commission, and in which this

Bureau had cooperated Avith other interests in drawing up specifications designed to improve scales, was advised, to the end that the

question of uncertainty in weights in loss and damage claims would

be reduced to the minimum.

GAUGE SECTION.

Research and Design,

Methods of measuring plain ring gauges have been examined, and

the conclusion has been reached that the determination of the internal diameter of the ring gauge can be accurately made by means

of two balls, the sum of whose diameters is slightly greater than the

nominal diameter of the ring. When two balls of these dimensions

are placed in the ring, resting on a surface plate, it is only necessary

to measure the difference in height of the tops of the balls to secure

sufficient data to compute the diameter of the ring. Steel balls can

be obtained that are round to one or two hundred thousandths oi an

inch. An apparatus has been designed and built for conveniently

and accurately measuring the difference in height of two balls placed

in a ring resting on a surface plate.

Some time has been spent in measuring experimentally the dimensions of gears with balls, cylinders, and gauge blocks on the sur-
EliPOET OF DIREGIOK OF BUKEAU OF STANDARDS. 47

face plate, and a method of determining the pressure angle of a gear

at any jDoint has been developed using these gauges. Additional

data have been secured which will assist in the design, of a geartesting machine.

A device for testing an extensometer, designed to measure the

compression in the piston rod of the recoil mechanism of large guns,

has been designed and successfully used in the test of the

extensometer.

A device employing an indicator was designed and built to measure

the variation in diameter of the bore of rifle barrels. This device

was used successfully in determining the variation in diameter of

used rifle barrels submitted for examination by the War Department.

Improvements in detail have been made in the optical projection lantern used in projecting images of profile and screw-thread

gauges. This instrument is now provided with a micrometer screw

accurate to 0.00002 inch. Changes have been made in the carriages

for holding gaviges so that larger gauges can be measured and long

screws, such as lead screws of lathes, can be examined. One of the

Bureau's lead testers or instruments for measuring pitch or lead of screws and screw gauges has been adapted to measure both the larger

gauges and longer screws, such as lathe lead screws. This enlarged

machine has been successfully used to measure the lead or pitch of

large-size pipe-thread gauges and also medium-size gear-cutting hobs.

The instrument could be redesigned to advantage to provide a much

heavier and more rigid machine for the convenient and accurate

measurement of large-size gear-cutting hobs.

An adjustable thread-plug gauge has been designed and built in

the shop for determining the pitch diameter of tapped holes. The

need for this instrument was felt* in connection with investigational

work requested by the National Screw Thread Commission.

Some time has been devoted to the problem of producing optical

flats in quantities by mechanical means. The method employed is an adaptation of the method used in. lapping precision gauge blocks

and gives promise of ultimate success. Several types of gauges were designed and made to gauge peai-1

buttons. These gauges have been submitted to the pearl-button

manufacturers for criticism and some comments have been received

which will aid the Bureau in designing more useful types of gauges'

for the industry.

Testing of Gears and Gear-Cutting Tools.

Great strides have been made in the last few years in the methods

of cutting gears. However, there is a constant demand on the part

1 of the users of gears for a more perfect article and a continual strivI ing on the part of the manufacturers of gears to satisfy this demand.

Since the nearness of approach to correct tooth outline and accurate

spacing of teeth determines the efficiency, length of wear, and amount

of noise when running, there has been an ever-increasing demand

for greater accuracy in gears. In some methods of cuttting gears

the greatest opportunity for advancement appears to lie along the

line of careful inspection and of improvement in the accuracy of

tools and machines used in cutting the gears. This inspection must

necessarily be coupled with a similar inspection of finished gears.

|i These remarks appljj^ particularly to the manufacture of gears by
48 REPORT OE DIRECTOR OF BUREAU OF STANDARDS.

the ho]>bing method. During the past year the Bureau has made

a special test of liobs for one manufacturer and has been requested

to test in the near future hobs made on a hob-grinding machine

recently designed by another. This latter concern is building the

machine at a considerable expense, because it is claimed that the

hobs supplied by regular hob manufacturers are not sufficiently ac- curate. The lantern and lead tester used in the inspection of thread

gauges are useful in measuring some of the dimensions of gears

and gear-cutting tools. There has been loaned to the Bureau by

the Pratt & Whitney Co. a Saurer gear-testing machine which indicates variations in the velocity ratio of a pair of spur gears. An attachment has been designed for this machine to indicate variations in the

velocity ratio of a worm and worm Avheel. This attachment is practically completed and will be tried out shortly to complete the test of a worm wheel for a motor truck. There is great need for a

gear-testing machine- employing the best practice now in use in

the testing of gears and gear cutters. The design and manufacture

of such a machine will be undertaken during the coming year.

Routine Testing of Gauges.

The number of lots and the number of gauges and other articles

requiring contact measurement submitted month by month are shown

in the following table :

Month.

July, 1920.... August

September... October November. .

December. . January, 1921

Number

of lots.

17

1614

17

10

17

Number

of gauges.

130

111 227 429

269 315

522

Montli.

February.

•March AprO

May

June

Total

Number Number

of lots. of gauges.

15 1 883

14 588

15 280

14 340

18 83

175 4, 17 7

1 This includes 766 polariscope tubes submitted by the Treasury Department.

Of the above gauges, about 27 per cent were submitted by the Government departments other than the Bureau of Standarcls, about 3

per cent by the Bureau of Standards, and 70 per cent by private concerns. During the preceding year 76 per cent of the gauges tested

were submitted by Government departments other than the Bureau

of Standards, and only 17 per cent by private concerns. The total

number of gauges submitted shows a slight increase over the preceding 3^ear, when 3.911 gauges were submitted. The great decrease in

the number of gauges submitted by the Government departments is due to the reduction in the manufacture of munitions and munition

gauges by and for the Government. It should be noted that this de- crease is practically counterbalanced by the increase in the number

of gauges submitted by private concerns intended for use in the

manufacture of commercial products.

Testing of Gauges for Commercial Concerns.

There is a continual tendency on the part of manufacturers to improve the quality of their product b^^ the reduction of tolerance on

jjarts intended to interchange. This reduction in tolerance must
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 49

asually be coupled with a reduction in the tolerance on the gauges

required to inspect the Avork. The diminished tolerance on the gauges

increases the difficulty of determining whether a particular gauge

is within the tolerance specified. Usually the gauge user is not

equipped to inspect all types of gauges with sufficient accuracy to

determine whether they are within the tolerance specified, and frequently the gauge manufacturer is not equipped with proper instruments and apparatus to make the measurements. It is in such cases that the Bureau is called upon to act as a referee to determine whether

the gauges should be accepted or rejected.

Judging from the class and variety of work submitted to the Bureau by manufacturers during the past year, there is a tendency to

require careful inspection of certain gauges and tools which formerly

the user accepted from the manufacturer without any question as to

accuracy. For example, this tendency has been noted in regard to

plain ring gauges and hobs for gears. In the first case certain users

of ring gauges are no longer satisfied with a mere statement that a standard plug gauge will enter the ring, as it is realized that a ring

gauge can be subjected to a large and variable force tending to ex- pand the ring when the plug is entered in the usual way. In regard

to hobs for gears, manufacturers of gears by the bobbing process have

felt the effects of keen comiDetition with gears made by other processes, especially ground gears, and in attempting to improve the

quality of their product they are inclined to require a rigid inspection

of the hobs used.

Finger-Ring Gauges.

A wide divergence has been noted in the dimensions of finger

rings and ring gauges of the same nominal size. The method of use of the gauges also varies. This tends to increase the difference between rings and gauges intended to be of the same size. The Bureau

has been unable to find any list of universal standard dimensions,

each manufacturer of both rings and gauges appearing to follow his

OAvn ideas as to what dimensions are proper. A preliminary schedule

of dimensions has been draAvn up and will soon be submitted to the

trade for consideration.

Shopwork.

In addition to instruments and devices designed in the laboratory,

of which mention has been made above, the shop has completed 5

projection lanterns, and 12 sets of adjustable parallels for the Ordnance Department and has built 1 lantern for the use of the gauge

section. Considerable work has been done in building regulating

apparatus and equipping the constant-temperature room.

Travel.

A member of the Bureau attended meetings of the American Society of Mechanical Engineers Committee on Plain-Limit Gauges and

meetings of the National Screw Thread Commission. Also, a trip

was taken to Providence, R. I., to testify in a suit involving a manufacturer of munition gauges. Testimony was given as to the methods employed in testing gauges and as to the accuracy of a lot

of gauges tested by this section. Tavo members of the staff visited

64984—21 4
50 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

several manufacturers of gears and gear-cutting tools, and much

valuable information was obtained as to the requirements of manufacturers and the methods of testing gears. A visit was also made

to several manufacturers of pearl and composition buttons and firsthand information obtained with regard to the problems and requirements of this industry.

National Screw Thread Commission.

A very considerable amount of work has been done by members of

the division in connection with the National Screw Thread Commission in its work on standardization of screw threads. This work is

especially important in the field of interchangeable manufacture of

machine products. A progress report has been issued which has

been very well received by engineers and by the mechanical industries and which marks a notable advance in screw-thread standardization. A program has been outlined for continuing the work, and it

is felt that this will result in still further progress.

American Society of Mechanical Engineers' Sectional Committee

on Unification and Standardization of Screw Threads.

The Bureau is represented by membership on the above committee, one of the objects of which is to pass upon the progress report of the

ational Screw Thread Commission, with a view to its recommendation to the American liingineering Standards Committee for adoption as an "American standard " as defined by that organization.

American Society of Mechanical Engineers' Sectional Committee

on Plain Limit Gauges for General Engineering Work.

The Bureau is cooperating with the above committee, the purpose

of which is to set up standards of practice in the manufacture and

inspection of machine products, with a view to securing economy of

production and efficiency of operation of these products. This work

is well under way, and it is hoped that a comprehensive report can

soon be issued which will aid materially in putting the design, construction, and inspection of machine fits on the sound basis of the

best engineering practice.

Standardization of Buttons.

A representative visited the headquarters of the fresh-water pearlbutton industry in Wisconsin and Towa to obtain information as to

the need and possibility of standardization in that industry. Much

valuable information on the methods of manufacture and inspection

was obtained, and it is believed that the Bureau can aid materially in

drawing up and putting into use definite standards of measurement

and quality of pearl buttons. The work of establishing standard

dimensions is already well under way and is being carried forAvard

by a committee of the manufacturers.

The establishment of standards of quality Avill be more difficult, as any classification as to grade or quality is necessarily based upon

the judgment of some individual or group of individuals. Some

progress, hov/ever, has been made, and most of the manufacturers

are '^hopeful of arriving at a reasonable degree of uniformity of

qualit}- as well as uniformity of dimensions.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 51

A visit was also paid to the manufacturers of composition buttons

at Auburn, N. Y., for the purpose of comparing the problems of the

two industries. It was found that the problems of manufacture and

standardization in the two industries are entirely different and

should therefore be considered separately.

PUBLICATIONS.

The following publications and information in mimeographed

form relating to the work of this division have been issued during

the year.

Progress Report of National Screw Thread Commission.

The National Screw Thread Commission, authorized by an act of

Congress approved July 18, 1918, completed its preliminary work of

standardization and issued a progress report covering the work done.

This report, published as Miscellaneous Publication of the Bureau

of Standards, No. 42, contains very comprehensive specifications and

tolerances for screw threads and much valuable information on screw

thread gauges and methods of gauging.

Jewelers' and Silversmiths' Circular.

A new circular, No. 43, Jewelers' and Silversmiths' Weights and

Measures, which covers a variety of subjects of interest to jewelers

and workers in precious metals, was issued and will serve as a valuable handbook for the trade.

Thermal Expansion of Copper and Its Alloys.

Data on the thermal expansit)n of 128 samples of copper and its

important alloys of various compositions, heat treatments, and mechanical treatments are given in Scientific Paper 410. Most of the

samples were examined from room temperature to about 300° C,

several specimens being cooled to —50° C. and then heated to

-f300° C.

Report of Annual Conference.

The report of the Annual Conference on Weights and Measures

was published, as usual.

Screw-Thread Pitches.

A paper has been prepared for publication in which a graphical

method has been used to convert screw-thread pitches from English

to metric unitSj and vice versa. Thermal Expansion of Metals.

A publication is now in press on the Thermal Expansion of Nickel,

Monel Metal, Stellite, Stainless Steel, and Aluminum.

Testing of Large Capacity Scales.

During the year there was prepared for publication Technologic

Paper 199, Method for the Precision Test of Large Capacity Scales.

This is a description and explanation of the method developed by the

Bureau of Standards for the precision test of scales, such as railroad

master scales and large grain hopper scales. However, the plan out-
52 EEPOBT OF DIRECTOR OF BUREAU OF STANDARDS.

lined can be adapted easily to the test of almost any weighing device,

and the publication, it is felt, will be valuable as a reference text for

most engineering laboratories where the need arises now and then

for the test of weighing mechanisms with more than ordinary precision.

Technical Data and Information.

The following technical data and information were prepared, in

mimeograph form, for distribution : Table of equivalents of United

States gallons in terms of British imperial gallons, and vice versa. These tables will also apply to other units of the same relative sizes,

such as TTnited States quarts to British imperial quarts. Table of

equivalents of cubic feet in terms of cubic meters, and vice versa. Weights of a cubic foot of limestone. This paper includes a discussion of the A^oidage or vacant spaces between the particles of sand,

gravel, and broken stones, and the weight of a cubic foot of broken

limestone and its dependence upon the specific gravity of the solid

material and the percentage of voids.

2. ELECTRICITY.

The work of this division covers electrical units, standards, measuring instruments,

and methods of measurement, including electromotive force, resistance, current, in- ductance, capacitance, 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 v/ith technical societies, testing laboratories, electrical industries, public service companies, public utility commissions, municipalities, and engineers in problems of standardization, including stand- ards of adequacy and safety of service, some of the work has been extended to cover more than strictly electrical service.

. GENERAL.

Scope of the Electrical Work.

One of the most important functions of the Bureau with respect

io electricity and allied subjects is the establishment and maintenance

of the fundamental standards upon which all electrical measure- ments are based, including cooperation Avith similar institutions in

other countries so as to secure international uniformity. This includes the intercomi^arison of standards, 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 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 tlirough the work

of such institutions that the measurements made in practice are referred back to the standards of the Bureau. Second, a limited

amount of testing of commercial electrical measuring instruments,

radio and photometric apparatus, magnetic materials, etc., is done

chiefly for the purpose of keeping the Bureau in touch with the

needs' of the industries, of developing methods, and of improving
EEPORT OF DIRECTOR OF BUREAU OF STANDARDS. 53

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. In general, this investigational work deals Avith fundamental properties and principles,

I so that the results may be applicable to a class of problems rather

than being limited to the one specific problem under investigation.

The Avork on correlation of magnetic and mechanical properties of

[ iron and steel and in the study of insulating materials are examples.

The research work in radiocommunication, magnetism, radioactivity, and photometry is along lines quite similar to that in the more

' purely electrical measiirements. Standards have 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

t the past j'ear are given in the sections below.

j Public Utility Investigations.

j Another important activity of this division, including more of

I engineering and field work than most of the electrical work referred

to above, is the investigation of problems arising in connection with

various public utilities, particularly electric light and power, gas,

street railway, and telephone services. The work includes (1) scientific and engineering research, (2) the study of the conditions which

determine the quality of public utility service of various kinds, (3)

I methods of testing and inspection employed by municipalities and

I commissions, (4) safety rules for use by the utility companies to

safeguard their employees and the public, and (5) the collection and

distribution of information by published papers and through corre- spondence.

This work is a natural outgrowth of the research and testing done

by the Bureau of Standards for the public utility companies and

commissions. The testing of electrical instruments and meters, of

gas lamps and the standards employed in measuring the cancllepower

and heating value of gas, the life testing of electric lamps, the test- ing of instruments used in telephone work, research on electrolysis

mitigation, and similar investigations and tests connected with the

j

I public utilities, have all involved to a greater or less degree questions

[ of standards of service. The Bureau has gradually accumulated a

' considerable amount of information on these questions and has been

i able to contribute materially to the establishment of standards of

quality in several of these services. Furthermore, it has promoted

j with marked success the practice of settling disputed questions in

I 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 a recognized position as mediator in such questions.

In many States the public service commissions have set standards

of service for the different utilities, and the Bureau has cooperated
54 REPORT OF DIRECTOR OF BUREAU CF STANDARDS,

with most of those that have done so. In other States these problems

are dealt with more or less independently by the different municipalities. For most cities and many commissions it is a difficult matter to

judge the quality of service rendered by the utilities. Obviously, it will never be economical or desirable for each 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 usually be settled

only by reference to what is done under similar circumstances elsewhere in the country. In other words, standards of good practice

and good service are largely determined by general experience and

should be studied comparatively, using the experience of the entire

country. The Bureau has been doing this for several years, and

although it has not been able to do as much as it would have liked it

has done enough to demonstrate the practicability and acceptability

of the method. It will 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. The present status of the utility work is summarized in the sections following those on electrical measurements.

STANDARDS OF RESISTANCE.

Routine Testing.

The demand for the testing of resistance standards, Wheatstone

bridges, potentiometers, and similar apparatus, and for the determination of the electrical properties of conductors has been greater

than at any time during the history of the Bureau. Not all of the

tests required could be taken care of, though more than half the

resources of the section were devoted to this work. •

International Comparison of Standards of Resistance.

During the year four of the Bureau's 1-ohm resistance standards

of the type used in maintaining the unit were sent to the National

Physical Laboratory of England for comparison with the English

resistance standards, and two of the 1-ohm resistance standards

belonging to the National Physical Laboratory were compared with

the Bureau's standards. This intercomparison serves to show accurately what, if any, difference exists between the units of resistance

used in the two countries. This is the first intercomparison of the

kind made since before the war, and it is gratifying to find that the

difference in units used is only a few thousandths per cent.

Refinements in Resistance Measurements.

In the use of Wheatstone bridges or potentiometers it is known

that in case there is leakage from the leads supplying the test cur- rent and from the leads to the detecting instrument, or in case the

test current is alternating and there is unbalanced capacity between

these leads and " ground," highly accurate results can not be

obtained unless certain precautions are taken. One of the means

used for getting definite balances in such cases is to ground one of

the leads to the detecting instrument. Investigation shows that this

is bad practice, since, while it may enable the establishment of a
REPORT OF DIRECTOE OF BUREAU OF STANDARDS, 55

definite balance, the results are more likely to be in error than if the

lead had not been grounded. The effectiveness of a ground on a branch in parallel with the source of current has been investigated

and compared with the effectiveness of a ground on a branch in

parallel with the detecting instrument. It is found that with reasonable care reliable measurements can be made when either device is used ; that in some cases it is more convenient to use one and in other

cases the other ; and that there is but slight advantage in using both

simultaneously.

Units of Resistance.

In England the suggestion has been made that the use of international electrical units be discontinued, and that all electrical units

be made definitely a part of the C. G. S. system. The measurement

of resistance in electromagnetic units—that is, in the so-called absolute units—has been given careful consideration. From time to time

a number of possible methods of measurement have been devised and

the relative advantages and disadvantages of these compared with

the method proposed by the late Dr. Eosa, of this Bureau, the method

used in the most recent and best work in the National Physical

Laboratory, and with various other methods either proposed or which

have been used. From this comparison a cpnclusion has been reached

regarding the methods to be employed and the type of apparatus to

be used as soon as funds are available for the construction of this

apparatus. This problem involves, among other things, accurate control and measurement of the speed of rotation of the machine used,

and considerable experimental as well as theoretical work has been

(lone on this phase of the subject.

The Statement of the Conducting Quality of Conductors.

This is a matter concerning which there has been a considerable

lack of uniformity and more or less difference of opinion. An investigation of the subject shows that several different procedures

might be followed in establishing units of resistivity ; that there is

need for units established in two different ways; and that there is

need for a convenient way of designating the units used in any

particular case. It is believed that if two units could be adopted by

international agreement and that if names could be assigned to these

units, as has been done for many of the electrical and magnetic units,

this particular branch of electrical measurements would soon be on a

satisfactory basis and the names adopted have as definite significance as those of the other electrical and magnetic units.

Resistance of Human Body.

The investigation of the electrical resistance of the human body,

reported upon last year, has been continued. New apparatus which

gives gi'eater refinement in the measurement has been constructed

and additional measurements have been made. While the resistance,

exclusive of the resistance through the skin and in the vicinity of

the electrodes, is definite, as previously reported, the resistance of the

same individual de]Dends somewhat on the extent to which the muscles

are tense or relaxed, and there is a cyclic change synchronous with

respiration which is just noticeable with tlie improved apparatus.
56 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Measurement on the same individual at different times shows variations much greater than the uncertainties in the measurements. A

paper on this subject was presented at the April meeting of the

American Physical Society, and the proceedings of this society will

contain a fuller report on the work.

Electrical Method for the Measvirement of the Rate of Natural Corrosion in Sheet Metal.

The electrical resistance of a definite portion of a sheet of metal

depends, among other things, upon the thickness. If, therefore, re- liable measurements could be made of the resistance from time to

time, they might be made to serve as a means for determining the rate

at which the thickness is decreasing as a result of natural corrosion.

A method for making such measurements has been developed and

tried out in the laboratory. Four point contacts are made on large

sheets, and the resistance of the four terminal conductors thus

formed is measured by a simple type of potentiometer. It was found

that the measurements can be made rapidly and with sufficient accu- racy for the jDurpose. The method is applicable to cases such as metal roofs, whether or not the}' are covered with a protecting coat,

such as paint.

INDUCTANCE AND CAPACITANCE.

Inductance and Capacitance Laboratory.

The routine testing which is requested of this section now con- sumes a very large part of the time of those who are working on

inductance and capacitance problems. Many of the tests can not be

made in any other laboratory in this country. They are, in effect,

research problems which are of great importance to manufacturing

industries. In order to handle these tests promptly, an increase in

personnel and laboratory facilities is necessary. A number of minor

changes have been made in the method of conducting the more routine tests in order to expedite measurements and calculations. This

has required the addition of a small amount of equipment, but the

saving in time has been considerable.

Inductance Research.

As the laboratory facilities are so largely used for testing work,

research work has been to a great extent confined to theoretical investigations. The integration method of deriving alternatingcurrent resistance and inductance has been extended to a three-phase

cable. An article on this subject is now in preparation. The same

method has been applied to determine the alternating-current inductance and resistance of a coil of wire. This will also be published

in the near future. By an entirely independent method a formula

has been derived for determining the alternating-current resistance

and inductance of parallel wires. This is applicable to a considerably larger range of frequencies than the formulas which have been

previously published.

A small amount of experimental work has been done on measuring

the inductance and resistance of parallel rods. This is needed in

order to check the theoretical formulas which have been derived.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 57

• Also, some measurements have been made on the indnctance and re- sistance of a specially constructed solenoid. The methods which were

developed for this have been used in measurinj? the resistance and

inductance of lightning-rod cables. This test was requested by a lightning-rod company in order to obtain more information concern- ing the properties of ithe materials which they are using.

Capacitance Research.

For several years a set of air condensers has been under observation in an attempt to learn the causes of changes in capacitance.

Observations are still in progress. More active work on this problem

will be undertaken as soon as facilities permit. A research Avas un- dertaken at the request of a manufacturer of electrical apparatus on

some large paper condensers. The capacitance and phase difference

of these condensers were measured at voltages ranging from 600 to

2,000 volts. Condensers of this type are now becoming of considerable importance.

BALLISTICS AND ALLIED PROBLEMS.

Cooperation with Navy Department.

Certain ballistic investigations which were started during the war

and involved precision electrical and time measurements have been

continued throughout the year at the request of the Navy Department. In addition some new problems have been undertaken, to

the solution of Avhich the facilities develo]Ded in connection Avitli the

ballistic work can be directly applied. The Bureau of Standards

has been making the necessary precision measurements (largely electrical) and interpreting the results obtained, while the Navy Department has provided the facilities for conducting the experimental

work. The specific investigations are as follows

Study of the Variation of Gun Pressures with Time.

The electrical gauge for measuring pressiires in guns as originally

designed was given a thorough test during the ignition firings at Indianhead in July, 1920. Some very satisfactory curves were obtained showing the variation of pressure with time. However, during

this firing some of the weak points of the gauge became apparent

and a neAV type of gauge has been designed. This has been tested in a bomb, but has not yet been given a service test.

I Primer Explosion Times.

A report on the results obtained by firing a large number of

primers in the laboratory is now being prepared. This work has

not been considered urgent and during a large part of the year has

had to give way to more urgent problems.

Ejection Velocities.

Some improvements in the method of measuring ejection velocities

on battleships have been made, but the results of experiments on the

IT. S. S. Temiessee indicate that s^ill further modifications are necessary. There is every reason to believe that this method is capable of

;i giving the required accuracy.
.58 KEPOBT OF DIRECTOR OF BUREAU OF STANDARDS.

Firing-Time Intervals.

Measurements of the physical firing intervals and subintervals during the ignition firing at Indianhead have given results of unusual

value. The time at which various events in the firing of the gun

occur are now known.

Interior Ballistic Formulas.

In attempting to determine the pressure inside the bore of the gun

from the acceleration of recoil, it was found that the ordinary ballistic formulas were not sufficiently accurate. It was therefore found

necessary to develop a formula which takes into account the fact

that the diameter of the powder chamber is different from that of

the bore of the gun. These new formulas are contained in an appendix to the report, on the ignition firing at Indianhead.

pressure in Recoil Cylinders.

Two different types of pressure gauges have been constructed for

obtaining the time-pressure curve in recoil cylinders. Also, an ex- tensometer has been constructed by which it will be possible to

measure the rate of extension of the piston rod of the recoil cylinder.

These results are needed in order to check properly the ballistic

formulas referred to above.

Velocity of the Projectile Inside the Bore of the Gun.

Apparatus has been constructed for determining the velocity of

the projectile in the bore of the gun by means of the expansion of the

gun barrel. This apparatus is now ready for trial.

Photography of Projectiles in Flight.

Some additional development work has been done on a camera

for this purpose. A timing system has been installed whifch will

permit measurements of the velocity of the projectile. While it has

not been used throughout the year to photograph projectiles, yet it has been used to study the incorrect functioning of a machine gun,

in which case it was necessary to take pictures at intervals of a few

thousandths of a second.

" Sao Paulo " Report.

A report on the results of certain tests in connection with the firing

on the Brazilian battleship Sao Paulo has been prepared and submi*^ted to the Bureau of Ordnance, Navy Department. This report

has been distributed by the Navy Department among officers of our Navy and to the Brazilian Government.

Measurements on the U. S. S. " Tennessee."

Representatives of the Bureau of Standards made measurements

•of the ejection velocities during the calibration trials on the U. S. S.

Tennessee. Measurements were made of two 12-gun salvos, and

in each 11 satisfactory velocities were obtained.

Measurements of the movements of the turrets were made during

the structural test firing on the U. S. S. Tennessee. This work was

done for the Bureau of Construction and Eepair, Navy Department,

.and a report has been rendered to that Bureau.
REPORT OF DIRECTOR OF BUREAU OF STANCARDS. 59

Physical Constants for Submarine Mines.

At the request of the Bureau of Ordnance a study has been made

of some of the fundamental physical constants of submarine mines.

In order to make these of value considerable mathematical analysis

has been necessary. A report on certain phases of this work has been

submitted.

Design of Oscillographs.

The Bureau has used in its ballistic work the General Electric

oscillograph with some modifications. These instruments were made

for an entirely different purpose and were not quite suited for this

work. At the request of the Bureau of Ordnance, Navy Department,

a complete new design of the oscillograph was made, keeping in

mind its use for ballistic investigations. Six oscillographs according

to this new design are now being constructed by the General Electric Co. for the Navy Department.

Investigations of Turret Movements and vStrains During Gunfire.

The Bureau of Construction and Repair, Navy Department, has

requested this Bureau to make measurements during the firing of the

TJ. S. S. California of the movements of the turrets as a function of

time. Similar measurements will be made on the strains in the

turret structures. In order to have satisfactory data from which

apparatus for the above measurements may be designed, some preliminary measurements were made on the Ij. S. S. Tennessee. These

measurements gave so much information concerning the behavior of

the turrets that the Navy Department has requested the Bureau to

make similar measurements on the U. S. S. Maryland.

A large part of the apparatus for conducting the work on the

U. S. S. California has been designed and constructed. Methods of

mounting this apparatus have been worked out in connection with

the Navy Department, and the necessary brackets are now being installed on the U. S. S. California at the Mare Island Navy Yard.

The investigation is a very elaborate one and will require at least an- other year for carrying out the experiments and completing the

report.

Study of Soluble Washers.

A study has been made in connection with the action of soluble

washers to be used as delay devices in submarine mines. One phase

of the subject was carefully studied in the laboratory and a report

thereon submitted to the Bureau of Ordnance, Navy department.

ELECTRICAL MEASURING INSTRUMENTS.

Testing of Electrical Instruments.

The amount of testing was nearly as great as for the preceding

year, in spite of reduced personnel. For this reason it has not

been possible to devote as muoh time as ought to be given to the

proper maintenance of the working standards used, the development

of improved apparatus, and the extension of the range of testing.

Electrical Tests of Ignition Apparatus.

This work has been carried on in cooperation Avith the automotive

section of the Division of Heat and Thermometry.
60 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Two papers dealing with the mathematical theory of the production of voltage in the " high-tension " magneto have been completed.

Experiments have been made on the lireakdown voltage of spark

gaps in which one electrode is heated. This simulates the conditions

existing in the engine. Such gaps shoAv a very marked decrease in

the sparking voltage under this condition, even though the bulk of

the gas in the gap is kept cool.

A very considerable amount of time has been occupied in replying

to questions in correspondence bearing upon ignition.

Cooperation with National Associations.

The section has been represented on the following committees:

Instruments and Measurements, American Institute of Electrical

Engineers; Insulation, Engineering Division, National Eesearch

Council ; Terminal Markings, Electric Power Club ; Unbalance Factor, Standards Committee of American Institute of Electrical Engineers. A number of committee meetings were attended and a list

of matters of terminology prepared for circulation among the members of the first-named committee with a view to securing ultimately

an agreement on the best practice.

The section cooperated with the subcommittee on liquid insulation

of Committee D-9, American Society for Testing Materials, hy collecting and digesting the results of an extended series of measure- ments on various types of spark gaps for testing transformer oil. This work was begun before the war, was held in abeyance for sev- eral years, and has noAv been completed and will be published in the

rejDort of this committee to the society.

Cooperation with Manufacturers.

Visits were made to the factories of the principal makers of

electrical instruments and meters in order to become familiar with

their manufacturing methods and products and to determine how the

Bureau could be of the most service to them. At the request of one maker a material was located which was superior to the one he had

been using. Further investigation along this line is in progress.

Manufacturers of electrical measuring instruments are dependent

upon electrical standards of all kinds, and are greatly interested in

the use and methods of testing of such apparatus. Hence, the

Bureau endeavors to furnish the data necessary in keeping these

instruments up to their high standard of excellence.

Development of New Apparatus.

The commercial application of high voltages has far outstripped

the facilities for their measurement. The section began the design

of an accurate .instrument for such measurements in 1916, but the

work was dropped at the beginning of the war. It has recently been

resumed, with plans for a much larger instrument capable of

measuring up to 250,000 volts, the highest voltage which is at i^resent

contemplated for power transmission. This work is of in-.-reasing

importance, because at these high voltages the insulation is the determining factor in design of transmission lines, and failure of insulation entails costly damage to apparatus and expensive shutdowns of

the industries served.
KEPORT OF DIRECTOR OF BUREAU OF STANDARDS, 61

MAGNETIC MEASUREMENTS.

General Magnetic Measurements.

Most of the work in general magnetic measurements, aside from

the usual amount of routine testing, has been clone in connection

"with a study of methods for testing very short specimens. In many

cases, especially for the study of very pure materials or of special

alloys of which only a limited amoimt is available, it is important

to be able to test rather small specimens. A number of possible

methods are now under investigation, and it is hoped that it will be

possible to work out a satisfactory solution of the problem.

Magnetic Analysis.

The purpose of magnetic analysis is to afford a knowledge of the

•qualitj^ of steel and steel products as regards freedom from flaws,

strength, etc., without in any way injuring the piece. The general

application of such a nondestructive method of testing Avould un- doubtedly effect great savings of both material and labor, besides adding to safety in the use of steel products. The saving would be

effected by the elimination of defective material before expensive

manufacturing processes had been applied, and by making possible

the use of all good material in a lot having such a quantity of unsatisfactory material that the Avhole shipment would otherwise be

rejected.

There has been an increasing interest in the subject on the part of

•engineers and users of steel during the last few years, and many

investigations are being carried on by industrial and educational

institutions. These investigators naturally look to the Bureau for

assistance in the development of testing methods and the collection

of correlation data for use in interpreting the results of magnetic

tests. The magnetic section has endeavored to meet this demand for

information and cooperation as far as its limited funds would permit,

Thermomag'mtic Analysis.—The apparatus for the detection and

study of the transformations which take place in the structure of

steel upon heating or cooling was partl}^ completed during the year.

This work has been practically at a standstill for some time, owing

to the resignation of the phj^sicist who was develoi^ing the method.

However, some progress is being made in this investigation as opportunity permits. The completion of this apparatus should

afford a means of obtaining much valuable information regarding

steel, which can be obtained in no other way.

Correlation Data.—^Most of the Avork on the correlation of the

magnetic properties of steel with its structure and mechanical properties has consisted in the study of a carbon steel of eutectoid composition (0.85 per cent C). A paper was issued in the early part of

the year entitled " The Magnetic Eeluctivity Relationship as Related

to Certain Structures of a Eutectoid Carbon Steel," and later another

was issued on " The Effect of the Rate of Cooling on the Magnetic

and Other Properties of an Annealed Eutectoid Carbon Steel." In

addition, some work has been done on a series of pure alloys of iron

and carbon. Data of this tjq^e are fundamental and necessary for the

proper development of magnetic analysis.

Detection of FIav;s and hnperfections.—The method for the detection of flaws and imperfections has been the subject of some study
62 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

during the year. In addition to experiments on the apparatus

already constructed, a new instrument was designed and built for

the testing of rifle barrels. This was done at the request of the

Army Ordnance Department and, upon completion, the apparatus

was installed at the Springfield Armory for investigational work

there.

Magnetic Test of Twist Drills.—In cooperation with a committee

of the American Society for Testing Materials, a test was made of

about 40 high-speed steel twist drills which had received various

heat treatments. After magnetic tests have been made b}'- different

members of the committee, the drills will be given cutting tests to see

if any relation con be discovered between the quality of the drills,

and their magnetic properties.

Magnetic Compasses.

The work on magnetic compasses, aside from the testing of a small

number, has consisted of an investigation concerning their use in

fighting tanks. This type of service presents some unusual diffi- culties, but the preliminary results are quite promising. A paper

was also issued on the Testing of Magnetic Compasses.

Miscellaneous Activities.

In addition to the experimental work in the laboratory, the magnetic section has cooperated by participation in conferences and work

on technical committees with various organizations who are interested in magnetic subjects, including the American Society for Testing Materials, the National Research Council, the National Advisory

Committee for Aeronautics, and others.

PHOTOMETRY AND ILLUMINATING ENGINEERING.

General Problems in Photometry.

In the solution of the problems in light measurement which havebeen raised by the rapid development of practical lighting units of

large size and high efficiency, slight progress has been made during

the year. The adoption of a standard method for the comparison of

the intensity of lights of different color is a matter in which international agreement is highly desirable. A meeting of the International

Commission on Illumination was held in Paris in June, 1921, and for

this meeting the Bureau prepared a report on the status of heterochromatic photometry, summarizing the recent work done here and

elsewhere on this problem. A report on primary standards of light

was also submitted to the International Commission, and both of these

problems were discussed in a paper presented at the December, 1920^

meeting of the Optical Society of America.

The growing use of gas-filled and other incandescent lamps with

coiled filaments, which can be reliablj^ measured only in an integrating sphere, has made that instrument practically indispensable in

any photometric laboratory. The fundamental theory of the sphere

as an integrating photometer is simple, but in practice there are many details of operation which require careful analysis in order

to avoid errors. There is no satisfactory^ discussion of the use of the

sphere available in English. To meet this lack a general paper on

the theory, construction, and use of the sphere has been prepared

and will be printed during the coming year.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 6.^

Instruments for Measurement of Reflected Light.

In the design of lighting installations and in many other problems it IS often necessary to know the reflection factors of walls, ceilings, and other surfaces. Until recently the determination of these

factors has been feasible only by taking samples to a laboratory provided with special equipment for the purpose. As a by-product of

the Bureau's investigations of the use of the integrating sphere in

photometry, an absolute refiectometer was devised some time ago.

This instrument is described in Scientific Paper No. 391, issued in

July, 1920.

-Further study of the problem has led to the construction of several

other reflectometers, one of which is described in Scientific Paper

No. 405. "A Simple Portable Instrument for the Absolute Measurement of Reflection and Transmission Factors." Like the earlier instrument, this reflectomoter makes use of the principle of the integrating sphere and has been found to give correct results on materials having a wide range of reflecting properties.

New Specifications for Incandescent Electric Lamps.

For about 14 years electric lamps have been purchased by the

j Federal Government under specifications published in Circular 13

i of the Bureau of Standards. Progress in the art of lamp manufacj ture has been so rapid that this circular has had to be revised eight

times in order to keep the specifications abreast of current developments. The original specifications covered only carbon filament

lamps. In later editions metalized carbon and tantalum lamps were

j introduced and then discarded, as tungsten-filament lamps gradually

I displaced them in use. In connection with these radical changes in

types of lamps, very great improvements were made in the efficiency

' and the life required, but no fundamental change was made in the

form of the specifications or in the methods of testing.

For the fiscal year beginning on July 1, 1921, new specifications

have been adopted, which include important changes in the test procedure for tungsten lamps. The new specifications will be issued as

jl the ninth edition of Circular 13.

jl The .most notable of the changes is the abandonment of the longI established provision that the life of test lamps shall be considered

^ as ended when the candlepower has fallen to 80 per cent of the

initial value. The specification of such an end point is convenient

! and reasonable in the testing of carbon lamps, because those lamps

will often burn for a long period after they have become so blackened

that they should not be continued in use. In tungsten lamps, however, means have been found to prevent excessive blackening of the

bulbs, so that the lamps normally burn out before their efficiencj^ has

fallen enough to justify replacing them. The new tests will therefore

be based on the total life to the time of burn out, thus conforming

more nearly to actual practice in the use of lamps.

The performance of the lamp throughout its life will also be

taken into account through two new provisions. One of these is the

evaluation of life-test results on the basis of average efficiency

throughout life, instead of the initial efficiency; the other is a re- quirement that the average light flux during the life of the lamp

must not fall below a specified percentage of the initial flux.
64 KEPOET OF DIRECTOR OF BUREAU OF STANDARDS.

Tests under these new specifications are intended to give a more

complete indication of the performance of lamps than the former

specifications did, and thus to discriminate more exactly between

types of lamps. In the first application of the new specifications it has, however, been deemed wise to make the requirements moderate.

The numerical values adopted for the various requirements have been

based on extensive studies of the performance of lamps in tests made

by various manufacturers as well as by the Bureau of Standards. It

is believed that they have been so adjusted that the change in specifications will involve no injustice either to lamp manufacturers or

to purchasers. It is recognized that for the first year the application of the new requirements should be more or less experimental.

Improvement in the ratings required will be based on this experience.

The carbon-lamp schedule has been retained because these lamps

still find some use, but the specifications for them are practically un- changed from those given in previous editions of this circular.

Inspection and Life Tests of Incandescent Lamps.

The quantity of lamps ordered this year by departments of the

Government was considerably greater than during the preceding one,

the total number being 3,000,000. The inspections made by the

Bureau covered about the same number. This is an unsual and en- couraging feature, since it indicates that samples representing practically ail lamps ordered were examined by the Bureau's inspector,

whereas during prcA^ious years considerable quantities have been

shipped without inspection. Such shipments without inspection are usually due to urgent need of the lamps, but in most cases it is practicable to place orders sufficiently in advance, so that immediate delivery is not necessary and the full advantage of inspections and

tests by the Bureau can be realized.

Of the total quantity ordered 78 per cent were large tungsten

lamps, as distinguished from miniature and carbon filament lamps.

Among these tungsten lamps the proportion of gas-filled lamps was

the same as last year, comprising approximately 16.5 per cent of the

number and 45 per cent of the total cost. The average size of gasfilled lamps ordered was between 100 and 200 watts, while 25 and 40

watt sizes have been most common on orders for vacuum tungsten

lam]DS. Tungsten miniature lamps comprised over 6 per cent of the

total. Consequently, approximately 16 per cent of the total ordered

were carbon lamps, of which about nine-tenths were large lamps.

The miniature carbon lamps were mainly instrument lamps required

for special service in the Navy Department. It appears, therefore,

that carbon lamps are rapidly being relegated to use in locations and

under conditions where it would be impracticable to install and operate tungsten lamps, thus conforming to best practice as recom- mended in the Standard Specifications for Incandescent Electric

Lamps under which the inspections and tests are made.

Life tests were completed on about 1,700 lamps. Of these 86 per

cent were large and miniature tungsten and the remainder carbon

lamps. There are as yet no standard specifications for miniature

lamps, but the test results obtained have furnished valuable data

for the preparation of such specifications, which are at present under

consideration.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 65

At tlie request of the General Supply Committee special inspections

and tests were made of the product of a prospective bidder on Government lamp contracts. A report to the committee on the results

of these tests was given due consideration in recommending awards.

Interlaboratory Comparison of Lamp Measurements.

The Bureau again participated in two interlaboratory comparisons

involving measurements of light output and electrical properties of

large and miniature lainps, respectively. In the first test—that of

large lamps—precision readings were first taken on the standard photometers of the Bureau. The lamps were then sent on circuit to

various testing laboratories. Final precision readings were then

taken at the Bureau. Eesults obtained by the laboratories were compared with the mean of the precision readings obtained by the Bureau. The laboratories were left free to take such action as they

chose to bring their readings into better agreement with the precision

values.

In the miniature lamp tests three brands of automobile lamps were

run on the spherical photometers at the various laboratories. At the

Bureau the standard 88-inch photometric sphere was employed in

the recalibration of standards for this work, and the 36-inch sphere,

using these standards, was emploj^ed in making the measurements.

It appeared from the results of these tests that there was need of further standardization of equipment and methods of measurement of

miniature lamps and of obtaining and maintaining satisfactory

standards of light output.

RADIO COMMUNICATION.

Radio Research and Information.

The research projects undertaken by the radio laboratory are determined to a considerable extent by the problems which are assigned

to the laboratory and for which certain funds are allotted by other

Government bureaus. In addition to work on th§ general program

of radio research attention has been given during the past year to

special problems for the Signal Corps, Air Service, and Bureau of

Markets.

The files of general radio information, radio patents, the radio

library, and radio references are becoming increasingly valuable to

men engaged in this work, both in the Government and in outside

organizations, and the Bureau of Standards is frequently consulted

for information on special subjects. Information has been given

to universities and others regarding equipment for radio research

and siibjects on which investigation should be conducted.

A list of radio-research subjects has been prepared and classified

for convenient reference. For this purpose and for the classification

of other radio material the laboratory has developed an extension of

the Dewey decimal classification to radio Avhich has found wide

application. About 150 technical reports have been prepared relative to the work of the laboratory, and many of these are available

for use in answer to inquiries regarding radio subjects on Avhich no printed publications are as yet available. Programs of radio

64984—21 ^5
66 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

research hare been prepared and suljmitted to the Signal Corps, Air

Service and Post Office Department.

Standardization of Terminology.

Continued study was given to the definitions of terms used in radio

and to the uses of symbols and notations emploj^ed in the publication of the results of theoretical and experimental work on electron

tubes and other radio subjects. The Bureau of Standards is co- operating closel}^ with the Standardization Committee of the Institute of Eadio Engineers in furthering the general adoption of

standardization of this sort.

Variations of Radio Signal Intensity.

During the year four tests of the fading or variation of intensity

of radio signals have been conducted with the cooperation of the

American Radio Eelay League. In each series a group of from 7

to 10 transmitting stations were operated on 2 or 3 nights per week,

the signals being recorded, simultaneously by approximatelj' 100 observers. It is expected that the analysis of these reports which is now being made Avill give valuable information on the general nature of the phenomenon of fading and the relations of this phenomenon to the meteorological conditions existing during the tune

of transmission.

Measurement of Received Signal Intensity.

A study of the various methods of measuring signal intensit}' was

contihueci, and reports were prepared on the audio-frequenc}' comparison method and the radio-frequency comparison method.

Antennas.

A study was made of the methods of measuring the constants of

antennas, and formulas were developed for the calculation of the

capacity of antennas of certain tj^pes. Measurements were made of

the cajDacity and, resistance at various frequencies of condenser an- tennas constructed in several forms and sizes.

International Union on Scientific Radio Telegraphy.

A member of the Bureau of Standards has been appointed technical

secretary of the American branch of the International Union of

Scientific Radio Telegraphy. In connection with the work in this

organization experiments were conducted on a method of measuring

the intensity and direction of strays and atmospheric disturbances,

especially at short wave lengths.

Electrpn Tubes.

A considerable amount of material was collected for a circular on

electron tubes in radio communication, but on account of the rapidly

changing staff of the radio laboratory and the appearance of other

books containing material on this subject the completion of this circular has been indefinitely postponed. A considerable amount of

the material is, however, available in the form of laboratory reports.

A theoretical study has been made of the relation of the constants

of electron tubes to the geometrical dimensions of the tube elements.
KEPOKT OF DIRECTOR OF BUREAU OF STANDARDS, 67

The theory of detector tubes has been studied and measurements

have been niade of the detector coefficient of a number of types of

tubes.

A perrhanent set for the determination of the characteristic curves of electron tubes has been constructed and measurements made on

sample tubes.

Theoretical and experimental work has been done on the power

output from electron tubes used as power converters.

Measurements have been made of the voltage amplification of

radiofrequency amplifiers, and a permanent measurino- set is .maintained for this type of measurement.

Radiotelephony.

Several laboratory reports and scientific papers have been prepared on the study of modulation phenomena in radiotelephone circuits, with special attention to the electron tubes used in radiotelephone apparatus.

Conferences were held in Washington and at Provincetown, Mass.,

with officers of the United States Coast Guard regarding the utility

of radiotelephony for communication with life-saving boats of this

service. Preliminary experiments to determine the requirements for

this work have been conducted, a transmitting and receiving set using

a coil antenna and mounted on a motor truck having been employed

as one of the communicating stations.

Phenolic Insulating Materials for Radio Use.

A technologic paper entitled " Properties of Insulating Material

of the Laminated, Phenol-Methylene Type " has been prepared. This

paper has been submitted to and approved by several manufacturers,

the properties of whose materials are given in this paper. The Bureau of Standards has received hearty cooperation from these companies in furnishing samples for measurement and in discussing

methods of manufacture, and it is felt that the results of the tests are of considerable value in the production of satisfactory insulating

materials for radio work.

Miscellaneous Insulating Materials.

The Bureau of Standards has cooperated with the American Society for Testing Materials in the preparation of specifications for

insulating varnish, adhesive insulating tape, and dielectric endurance

tests. Measurements have been made of the phase difference of a number of miscellaneous insulating materials, such as glass, paraffin,

beeswax, wood, halowax, ceresin, and impregnated blotting paper. A

condensed summary has been prepared showing the properties and

uses of various kinds of insulating materials.

Radio Testing.

The methods of measuring wave length (frequency) have been improved by the development of apparatus which makes possible a ver3'

accurate comparison between the radio- frequency current from an

electron-tube generator and the upper harmonics of a standard

tuning fork. The same apparatus is used for an accurate measure- ment of the constants of inductance coils. The standard condenser,

inductors, and wavemeters have been improved to supply the need
68 KEPOET OF DIRECTOR OF BUREAU OF STANDARDS.

for greater precision in radio measurement. Apparatus has been

constructed for the measurement of impedance at frequencies varying

from audible frequencies to high radio frequencies. The apparatus

for comparing ammeters has been improved, and standard ammeters

are available to measure radio- frequency currents from 50 milliamperes to 100 amperes. Wavemeters, ammeters, condensers, and

other radio instruments have been tested for Government bureaus,

educational institutions, commercial laboratories, and others. An

effort is being made to interest commercial testing laboratories in

equipping themselves to test radio apparatus. A circular on radiotesting methods is in preparation.

Measurements of Telephone Receivers.

Some preliminary measurements of the voltage sensitivity of telephone receivers and of a standard thermophone were made employing a sound-proof room to minimize interference from outside noises.

ExiDcriments were condiicted in the comparison ,of the signal intensity produced by a current of two wave forms, a sine wave and

an approximate rectangular wave. Measurements were made of the

radio-frequency impedance' of a large number of pairs of telephone

receivers submitted for this investigation by the manufacturers.

These measurements show that the telephone receivers may have

electrical resonance at frequencies within the range of those used

for radio communication.

Properties of Inductance Coils.

A theoretical and experimental investigation has been made of

the capacity and resistance of inductance coils of various types, including the following: Short single-layer solenoid, multi-layer coil

of square cross section, flat spiral, elliptically shielded coil. A study

has been made of the skin effect in single-layer solenoids and straight

wires. Charts have been prepared for use in the design of inductance coils. Methods have been developed for the calculation of

the inductance of several special forms of inductance coils. Papers

describing this work are in course of preparation at the present time.

Airplane Radio.

Assistance was given to the Air Service in the inspection of radio

apparatus for controlling airplanes in flight. Experiments on the

use of radio, as an aid to aerial navigation included the transmission

of signals from two large coil aerials placed at an angle of about

45°. The system makes use o.f the directional transmission characteristics of coil aerials, the airplane i-eceiving station being able to

hold its course by flying along the line where the signals from the

two transmitting coils are of equal intensity. This system will

doubtless find other applications, as, for example, in guiding ships

along a certain course during fog. A study has been made of previous work in an effort to reduce the interference caused in a radioreceiving set by the currents in the airplane engine-ignition system.

Experiments have been conducted in the laboratory which indicate

that by means of very complete shielding of the ignition wires a

satisfactory solution of this problem may be secured. Some consideration has been given to a radio method for an airplane groundspeed indicator.
KEPOET OF DIRECTOR OF BUREAU OF STANDARDS. 69

Direction Finding.

In cooperation with the Signal Corps a direction finder was deA'eloped for use on a motor tractor. Two crossed coils are used, so that the signals from the transmitting stations can be heard at the

same time and the direction accurately determined. Experiments are

still in progress in the improvement of this apparatus.

Radio Fog Signaling.

Improvements were made in the antennas and automatic keys used

at the radio beacon stations at Fire Island Lightship, Ambrose Channel Lightship, and Sea Girt Lighthouse in New York Harbor. The

direction finder on the lighthouse tender Tulip was calibrated, and,

after preliminary navigation tests on the Tulip and endurance tests of the transmitting stations, demonstration tests were conducted at

which the practicability of this system of radio fog signaling was

shown to a number of representatives of shipping companies. Government officials, radio manufacturers, and others. Preliminary specifications have been prepared for the construction, installation, and

operation of the direction finder on shipboard. An exhibit of the

radio fog signal system was prepared for the American Marine

League Exposition at Philadelphia, Pa.

Radio Receiving Sets.

The Bureau is receiving an increased number of inquiries for information regarding radio receiving and transmitting apparatus

available on the commercial market. Through correspondence with

radio manufacturers there has been compiled information regarding

radio receiving sets and the parts from which sets can be assembled.

At the request of the Bureau of Markets an investigation is being

made of receiving sets suitable for use in receiving the radio market

reports. A conference was held with manufacturers of apparatus of

this type, and preliminary arrangements were made for a field laboratory for conducting receiving experiments.

Radio Broadcasting.

Assistance was given to the Bureau of Markets of the Department

of Agricultiire in the establishment of an experimental radio market

service. Market reports were transmitted from the Bureau, of Standards station for about four months before this service was taken over hj the Post Office Air Mail radio stations. Technical assistance was

given to the Bureau of IMarkets on such matters as the wave length,

speed, and time of transmission, form of reports, and other features

connected with the satisfactory transmission and reception of these

reports. In conjunction with the Bureau of Markets a pamphlet has

been prepared entitled ''Radio Information Circular Xo. l:-Eadio

Market Service."

Miscellaneous Applications of Radio.

Radio methods and radio instruments are being used for a large

number of scientific and technical purposes. Among those to which

the Bureau of Standards has contributed during the past year are the development of apparatus for measuring extremely small lengths,

the operation of electron tubes in generating sound, and the develop-
70 EEPOET OF DIKECTOK OF BUREAU OF STANDARDS.

ment of a spark sj^stem for studying the timing of electric make-andbreak circuits.

ELECTRIC BATTERIES.

Tests of Electrical Batteries.

Fortj^-eight tests have been made for various Government departments and a few commercial concerns on 566 batteries. The branches

of the Government submitting batteries for test were the Panama

Canal. General Supply Committee, the Motor Transport Divis-ion,

the Signal Corps of the Army, United States Shipping Board, the

Bureau of Engineering, and the Bureau of Ordnance of the Nav}^

Department. The batteries submitted for test included various sizes

of dry cells, flashlight batteries, storage batteries, and railway-signal batteries. In addition to these tests the Bureau has collected

and tested 1,192 batteries of various kinds to obtain information re- quired in writing specifications, to prepare circulars of information,

and to render assistance to various manufacturers and users of batteries. There Avere included in these 296 batteries manufactured in

England, France, Denmark, and Sweden. These batteries have been

tested in a manner similar to the customary tests on American-made

batteries in order to learn how the product of American factories

compares with that of foreign factories. At the close of the fiscal

year this test is still in progress.

Electrical Performance of Dry Cells.

An extended series of tests of dry cells in addition to the routine

tests has been carried out, on the basis of which a report was made

to the Signal Corps on (a) the temperature coefficient of voltage, of

short-circuit current, and of capacity; (6) the period of useful discharge for different types of cells at different rates of discharge, including discharge at constant current and through constant resistance; (c) the potential relations of the positive and negative electrodes of paper-lined and bag-type cells; (d) a series of curves showing the ampei'e-hour and watt-hour capacity of dry cells discharging at different rates; (e) a series of tables giving a survey

of tests made on the princijial batteries of American manufacture

and summarizing the results obtained on 800 batteries. There has

been a lack of engineering information on the electrical performance

of dry cells. The Bureau's circular, No. 79, on this subject has been

very favorabl}' received, and it is proposed to rewrite this circular,

maidng iise of the data obtained in the investigations that have been

carried out during the past year.

Storage-Battery Investigations.

Effect of Impurities in Storage-Battery Electrolytes.—This investigation Avas begun at the reciuest of the Bureau of Engineering,

Navy Department, to determine the cause of failure of the negative

j)lates in the battery of a submarine. Samples of the electrolj'te and

of the negative plates Avere submitted. The work consisted of a careful chemical and spectroscopic test of the material. The results of

this test emphasized the need of more extended investigation of the

effect of impurities in storage-battery electrolyte. Preliminary work

on sucli an investigation AA'as begun at the close of the fiscal year.

The results of such an inA-estigation would be of use not only to the
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 71

Navy Department, but to the manufacturers and users of storage

batteries who have become very numerous through the adoption of

10, the storage battery for starting and lighting automobiles.

.Automobile Batteries.—A special report to the Motor Transport

Division of the Army was prepared describing the experiments made

by the Bureau to determine the service which a battery performs in

starting various types of automobiles. During the course of these

experiments it was found that the instantaneous measurements of the

voltage and current in the battery circuit can afford valuable information as to the performance of the starter system and the engine itself.

The oscillograph records suggest the possibility of using this method

to study the effects relating to torque, temperature, compression,

lubrication, distributor action, and flywheel velocity, in addition to

the information obtained about the battery and starter system. The

material contained in this report has been published in Technologic

Paper J^o. 186'. Study of Wood Separators.—Wood separators are used in nearly

all types of modern storage batteries. The durability of such separators in strongly acid solutions and the porosity which permits the

flow of an electric current through them are features of great importance. A method for determining the resistance of these separators has been devised and measurements made of a considerable

number of different kinds of wood. These experiments should be

extended to include the determination of porosity, the resistance of

the wood to the charring action of the acid, and' the extent to which

these separators liberate deleterious impurities in the electrolyte.

Effect of Low Temperatures on the Voltage of Batteries.

Tl;iis investigation was made to obtain information required by the

Carnegie Institution in designing apparatus to be used at the magnetic North Pole for observations of atmospheric electricity. It was

found that both dry cells and storage batteries can give an open-circuit voltage of approximately normal value at temperatures as low

as —64° C, the temperature coefficient is small, having positive

values at some temperatures and negative values at others. Dry cells

at such exti-emely low temperatures can not, however, furnish an

appreciable amount of current. Dry cells after being frozen return

to normal when brought back to normal temperatures.

Comparison of American and Foreign Makes of Dry Cells.

Information obtained with respect to the performance of foreign

makes of dry cells is of value to the military departments and to the

American manufacturers of such cells. For this reason about 300

dry cells from several European countries wei-e obtained through the

Bureau of Foreign and Domestic Commerce. In order to obtain the

maximum of information with respect to these cells, they have been

preserved, following the completion of the electrical tests, by opening

the cells, washing out the paste, and preserving the parts after drying in such condition that they may be examined at any time by

those interested.

Signal Corps Textbook on Radio Telegraphy.

In connection with the revision of the book on " Principles Underlying Radio Communication," which was prepared b}' the Bureau
72 EEPOET OF DIRECTOR OF BUREAU OF STANDARDS.

for the Signal Corps, the section on electrical batteries has been

completely rewritten. The elementary theory of electrical batteries

is outlined and brief descriptions of the various kinds of dry batteries and storage batteries are given. Necessary' directions for the

proper use of A^arious types of batteries for field and laboratory

service are also included.

Preparation of Specifications for Electrical Batteries.

At the request of the Motor Transport Division specifications were

prepared for starting and lighting batteries for automobiles. In the

preparation of these specifications the Bureau had the cooperation of

batterj^ manufacturers and the Society of Automotive Engineers.

These specifications Avere discussed at three conferences and were subsequently adopted b}^ the War Department. The general form of

these specifications was worked out during the preceding j^ear, but

the adoption of a table of standard sizes of batteries proved to be the

most difficult part of the undertaking. The specifications as finally

adopted on September 28, 1920, included a table of 14 standard sizes

chosen from about 150 sizes now being made by A'^arious manufacturers. It was estimated that these 14 sizes Avould accommodate

more than 90 per cent of the American-made cars and trucks of

recent models. This fact shoAvs the need for such standardization.

If the number of batteries being manufactured could be limited to a reasonable number of sizes, the cost of manufacture could be reduced

and a large saAdng to the general public effected.

A represent atiA^e of the Bureau was appointed a member of the

storage battery subcommittee of the Standards Committee of the

Society of AutomotiA-e Engineers. This society has noAv revised its

standards to conform to the specifications for starting and lighting

batteries prepared by this Bureau for the Motor Transport DiA'ision.

This material is contained in the report of divisions to the standards

committee presented at the meeting of Januarj^ 11, 1921.

A representatiA'e of the Bureau is also a member of the subcommittee on storage batteries of the Standards Committee of the

American Institute of Electrical Engineers. A series of standard

definitions and nomenclature for storage batteries Avas prepared and

was adopted by the standards committee of the institute on Maj^ 19,

1921.

Specifications for railway signal batteries prepared during the

preceding year by the Battery Committee of the American Eailway

Association, with the assistance of a member of the Bureau of

Standards, were recently adopted.

Specifications for dry cells previously prepared by the Bureau

have now been carefullj^ studied in connection with the large amount

of testing carried on during the last year. The results of these tests have shoAvn that in general the specifications prepared by the Bureau

are satisfactory and in only a few cases will a revision of these specifications be necessary. It is expected to make use of the large

amount of data noAV available for this purpose.

Standard Cells.

Work on standard cells Avas confined for the most part to testing,

Avhich Avas noticeably heavier than during the previous year.

If
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 73

Late ih the fiscal year ended June 30, 1920, selected standard cells

were sent to the National Physical LalDoratory in England, and to

the Electi'otechnical Laboratory in Japan for the purpose of determinino; the order of agreement of the international volt as

realized in the three countries. Unfortunately, the cells sent to

England have not yet been returned and the cycle of measurements

on these cells has not been completed. Measurements made here and

in Japan, however, show the basis of reference in the two countries

to be in very close agreement.

RADIOACTIVITY AND X-RAY MEASUREMENTS.

Gamma-Ray Measurements of Radioactive Material.

The amount of gamma-ray testing of radium and mesothorium

has been so very heavy that practically all other work of the section

has had to give way to it. For this reason, and because of the lack

of sulRcient competent help, there has been no opportunity for investigation and research work. As in the preceding year, requests

for X-ray and luminous material tests have not been encouraged,

while many requests for alpha -ray and beta-ray examinations of

crude materials and partial concentrates have been refused, of

necessity, though some of this work, especiallj'^ that on partial concentrates, seems to the Bureau to be very important.

During the year 2,058 preparations, totaling 35,670 milligrams,

or over 354^ grams, of radium and mesothorium were measured and

certified by the section, while during the entire preceding six and

one-half years a little less than 58 grams were tested and certified.

The material certified during the fiscal year 1921 has a market value

of $4,000,000.

The increase of the work during the seven and one-half j^ears since

routine testing of these materials was begun by this Bureau is shown

in the following table

Year. Number

of tests.

Equivalent milli- grams of radium.

Year. Number

of tests.

Eciuivalent milli- grams of radium.

1914 (haU year) 2898

177

292

486 2,097

4,531

6, 638

1917-18 1.248

i;068

1,413 2,129

5, 376

13, 367

25, 278

35, 565

1914-15 1918-19 1915-16 1919-20

1916-17 1920-21

1

As the different radium-producing companies now quite generally

have their radium preparations certified in their own names and

returned to the com])any's office, the Bureau has no satisfactory or complete data on which to base estimates as to the quantity of material exported. However, information is at hand showing that during the fiscal 3^ear radium preparations were exported to Canada,

England, Holland, Belfjium. France. Italy, Ja))an. India, Denmark,

Australia, Argentina. Brazil, Peru, and Porto Rico.

Self-Luminous Materials.

These materials are composed chiefly of phosphorescent zinc sulphide, with a very small percentage of radioactive material, and are
74 EEPOET OF DIRECTOR OF BUREAU OF STAJ^DARDS.

used wherever a faint and entirelj' self-contained illumination is desired. A few years ago certain investigations Avere made by this

Bureau concerning the amount of illumination which was necessary

under various conditions, and the degree of brightness of different

materials, as well as their effective life. Financial limitations and

the large amount of gamma-ray testing demanding attention has

made it impossible to do much along these lines during the year just

closed. Many requests have been received from manufacturers, Government departments, and private individuals for detailed information as to the exact composition and methods of sj'nthesis of the

various self-luminous compounds^ but as these data are largely held

as commercially secret very little mformation is available for dissemination. Eighteen hundred samples of radium luminous tubes se- lected from a purchase of 180,000 by the Bureau of Ordnance are now about to be tested for luminosity.

X-Rays.

As mentioned aboAe. the Bureau's X-ray investigations have for

the present been practically discontinued. A very few radiographs

of samples of metal have been made for the purpose of detecting

flaws. Much work yet remains to be done in the investigation of

ojDei^ator-protecting screens and materials for fluoroscope screens, as well as in the standardization of methods of measuring or gaging

X-ray intensity, penetration, and therapeutic dosage. Limitations

of time and funds have j^revented the support and attention that this

work deserves.

ELECTROLYSIS PREVENTION.

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 bv Avay of the tracks and earth, some of it, however,

often flowing through underground gas and Avater pipes and the

lead sheaths of underground telephone and electric-light cables and

sometimes through reinforced-concrete structures. The earth con- ducts electricity by A'irtue of its moisture and the salts dissolved in

it, which render it an electrolyte. Hence, when the electric current

flows away from the 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 cur- rent travels back to the stations is relatively great. Many remedies

haA'e been proposed and tried, but no standard practice for the handling of the retiirn current has ever been agreed upon in this country.

As the electric raihvays haA-e been extended and traffic has become

heaviijr, the volume of current handled has increased A^ery greatl}^,
REPORT or DIRECTOR OF BUREAU OF STANDARDS. 75

and the resulting destructive effects, which are cumulative Avith time,

(Lave become increasingly evident. In some cases litigation has re- sulted between the pipe-owning companies suffering damage and the

railway companies whose current causes the trouble. However, in

spite of the fact that the courts have considered the question of legal

responsibility, these cases have done very little to prevent the trouble

in an effective and economical manner.

Economic Importance of the Electrolysis Problem.

i 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

I quarters that its importance deserves. When one considers the

I enormous value of the pipe ahd cable properties buried in the streets

of cities and forming in many cases transmission networks between

ci'-ies throughout the country, and considers further that there are very few water, gas, or lead-cable systems which are not more or less

subject at some points to electrolj^tic damage from stray currents,

d it is possible to form a better judgment of the practical importance

1 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 bil-

' lion dollars, and, in addition to this, there is a vast extent of undei;-

ground lead-cable systems belonging to telephone and electric-power

companies and to mimicipalities. There are also possibilities of

trouble in the case of bridge structures, portions of steel-frame

huildings, and piers, which are occasionally exposed to damage from

this source.

T\'Tiile 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 caused by 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 traceable

solely to electrolysis; but it is only necessary to assume that a small

per cent of the total is brought about by the more rapid development

i 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.

j It is not alone the property loss, however, that makes the elecj trolysis i^roblem one of importance. An important fact is the inconvenience to consumers of water, gas, and telephone service resulting from 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

I pipes are disconnected or when different pipe systems make moj mentary contact. Accidents of this kind are rare, but they have

j sometimes occurred, resulting in the loss of life and a considerable

f damage to property. Cases have occurred also in which leakage of

gas resulting from electrolytic corrosion of the pipe has given rise

to explosions with disastrous results. Maiiy gas explosions in base-
76 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

ments and manholes have occurred, and, although it is difficult to

determine what proportion is brought about by electrol^'sis, un- doubtedly 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 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, Avhen 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 recognized.

Investigation of Lead Corrosion Troubles in St. Louis.

The investigation of the corrosion of lead cables in the city of St.

Lrouis, mentioned in last ^'ear's report, was completed during the past

3^ear and the final rejDort submitted. This investigation showed that

there were in all five separate causes contributing to the burn outs

which in the order of their importance are as follows*:

1. Electrolysis due chiefly to lack of drainage at the time the cables

were installed.

2. Overheating, due to deterioration of the insulation as a conse- quence of injury to the sheath, and ]30ssibly, also, to the nearness of

the ducts to the surface of the streets and the restriction of circulation of the air by the use of too small a duct.

3. Chemical corrosion during the periods in which the street railway substations were inoperative due to the collection of alkali about

the sheaths as the current flowed through the earth to them.

4. Surges set up by switching and burn outs.

5. Mechanical injuries, etc. The investigation of these burn outs brings out the importance of

a careful provision against electrolysis at the time of the installation

of underground cables and the dangers of chemical corrosion due to

too heavy drainage.

Cooperation with the American Committee on Electrolysis.

About a 3^ear and a half ago definite arrangements were made for

active cooperation with the American Committee on Electrolysis in

the further prosecution of electrolysis investigations. This committee consists of 27 members, 3 each representing the following or- ganizations : American Institute of Electrical Engineers, American

Electric Railway Association, American Railwa}^ Engineering Association, National Electric Light Association, American Gas Association, Natural Gas Association, American Telephone and Telegraph

Co., American Water Works Association, National Bureau of

Standards.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 77

It will be seen that the Bureau has in this investigation the active

cooperation of all the great national associations of utility companies.

During the past year somewhat extensive field investigations have

been carried out in close cooperation with this committee, the utility

interests themselves having incurred considerable expense in connection with these researches. It is planned to continue this cooperation

during the coming year.

Development of Apparatus for Making Electrolysis Surveys.

One of the most serious obstacles to satisfactory prosecution of

the cooperative work by the Bureau of Standards and the American

Committee on Electrolysis has been the fact that existing methods of

electrolysis testing are wholly inadequate and do not give definite

and reliable information from which correct conclusions can be

drawn. The Bureau and the utility interests participating in this

work have long recognized the great need of the development of new

and improved methods for carrying out tests of this character.

During the past year the Bureau has pushed vigorously the development work on some entirely new methods and apparatus for

carrying out tests of this character and with very promising results.

The Bureau is now experimenting in the field in a preliminary way

with some recently completed testing sets, which, if they continue to

prove successful, will place electrolysis testing on a much more scientific basis than it has occupied heretofore. There is urgent need of

a thorough study of these new test methods in the field under practical conditions, with the Adew of determining their sphere of useful- ness and of developing the technique of their application. It is

planned to make this the first and most important subject of the joint

investigation to be carried on during the coming year by the Bureau

of Standards and the utility associations cooperating with it.

Electrical Telemetric Devices.

During the past year a large amount of work has been done by

the Bureau in the application of a new electrical telemetric device

for the measurement of stresses in structural members. This device

consists essentially of a series of contact resistances, preferably of

carbon, so arranged that the phenomena to be measured, such as pressure or displacements, will cause variations in the contact pres- sure of the contact resistance, and consequently cause variations in

the electrical resistance of the unit. These variations in the electrical resistance can be indicated or recorded at any desired remote

station. The chief applications of this device at the present time

have been in the measurement of stresses, and the work done by the

Bureau has been with particular reference to the measurement of

stresses in airplane stay wires and in portions of the rigid frame

of lighter-than-air machines.

A number of instruments have been designed and built for the

Naval Aviation Service, and these are now almost completed and

will be given a preliminary trial in a few weeks. The Bureau

plans to continue development work on some recording devices for use in connection with these instruments at the special request of the

Bureau of Construction and Eepair of the Navy Department.
78 KEPOET OF DIRECTOR, OF BUREAU OF STANDARDS.

SAFETY ENGINEERING AND SAFETY STANDARDS.

National Electrical Safety Code.

The Bureau lias been engaged for eight 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 wth 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 principar parts, as follows:

1. Rules for the installation and maintenance of machinery, switchboards, and wiring 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.

3. Rules for the installation and maintenance of electrical apparatus 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 electrical machines or lines.

The code is intended to be adopted by State industrial and public

service commissions and municipalities and to be complied Avith by

public service and industrial cori^orations. It is also intended to be

adopted voluntarily by electrical interests when the code has 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 standai^dization 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 Avas published in November, 1916, with a recommendation for

actual field trial.

The third edition of the Electrical Safety Code was published

under date of October 31, 1920, but was not actually issued until the

early part of 1921. This edition is known as Handbook No. 3. The
PP' REPORT OF DIRECTOR OF BUREAU OF STAJTDARDS. 79

discussion has been separated from the rules and issued as a separate

|P volume known as Handbook No. 4.s Both the rules and the discussion have been extensively revised and amplified, and this edition of

the rules is in suitable form for adoption hy State commissions, municipalities, and other ap:encies having appropriate jurisdiction.

Such mandatory application of the rules is already being made, the

States of Nevada, Tennessee, and North Dakota having adopted rules

based on the third edition and a number of others having them in course of preparation. Other administrative bodies had previously

! adopted rules comprising this code in whole or in part, and it is generally recognized as the most complete and satisfactory standard

in its field.

A pictorial edition of the rides showing their application by illustrations is in course of preparation. It is also expected to publish

a volume of engineering data referring to matters connected with

the rules or with overhead-line construction. These data will inelude more extensive tables for the sags of conductors and will in-

' elude tables regarding the supporting structures, such as wood poles

and steel towers. »

! Electrical Safety Conference.

The Electrical Safety Conference has been organized to promote

b}' cooperative action the orderly, consistent, and proper deA^elopj ment of practice in electrical manufacturing and installation with

I regard to accident hazards. Its membership includes representatives

of the Associated Manufacturers of Electrical Supplies, the Electric

1 Power Club, the National Workmen's Compensation Service Bureau,

Underwriters Laboratories, and the Bureau of Standards. Detailed

I standards for construction and installation of apparatus will be

worked out in harmonj^ with the Electrical Safety Code. The conference has already issued a standard for Industrial Control Equipment and has a number of others in course of formulation.

Industrial Safety Standards.

As a result of the work on the National Electrical Safety Code and

the nmnerous 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 countr3^ The conference voted in

favor of having safety codes prepared under the auspices of the

|i American Engineering Standards Committee. It also provided for

I the formation of a joint safety code committee to prepare a list of

codes already in existence or urgently needed and to recommend

' sponsors for preparing and revising these codes. Such a committee

was organized hj the National Safety Council, the International

Association of Industrial Accident Boards and Commissions, and the
80 EEPOET OF DIKECTOE OF BUEEAU OF STANDARDS.

Bureau of Standards. This committee is known as the National

Safety Code Committee. It has,made recommendations to the American Engineering Standards Committee for about 40 codes, and most

of the recommendations have been approved by that body.

The codes recommended for sponsorship by the Bureau of Standards are the following : Electrical Safety Code.

Gas Safety Code (joint sponsorship with the American Gas Association).

Code for the Protection of Heads and Eyes of Industrial Workers.

Combined Electrical Fire and Safety Code (joint sponsorship with the National

Fire Protection Association).

Code for Protection against Lightning (joint sponsorship with the American

Institute of Electrical Engineers).

Safety Code for Logging and Sawmill Operations.

Safety Code for Aeronautics (joint sponsorship with the Society of Automotive Engineers).

A number of safety codes are being developed by sectional committees organized by other Federal bureaus and engineering societies as sponsors. The Bureau is rej)resented upon a number of these committees and is doing active work in cooperating with such committees

in the development of these codes. Among those in the preparation

of which the Bureau has given active assistance are the Elevator

Safety Code, the Code for Safe Guarding Power Transmission Apparatus, and the Code for the Woodworking Industry.

Heads and Eyes Code.

The National Safety Code for the Protection of the Pleads and

Ej^es of Industrial Workers was completed and published during the

year, and it has been approved by the American Engineering Standards Committee. This code states the t3^pe of protection needed in

various groups of industries and includes specifications for the

goggles, helmets, and other devices which shall be used to provide

such protection. It has been generally recognized as the most authoritative work upon this subject.

Logging and Sawmill Code.

A rough draft of this safet}'^ code was prepared from a study of

existing requirements and the Bureau's general knowledge of such

operations. Field inspections Avere made by members of the staff

in the Virginia woods, and later in the South as far as Louisiana,

and in New York State and New England. As a result of these

field inspections a revised draft of this code was prepared and has

been circulated among those interested in the subject as a tentative

suggestion to be used as a basis for the complete code. Comments

and criticisms upon this draft have been gathered and submitted to

the Sectional Committee, Avhich is cooperating in the completion of

this code. Additional material has also been prepared and it is

expected to issue a complete code during the foithcoming year. The

Sectional Committee referred to has been organized according to the

scheme of procedure of the American Engineering Standards Committee and contains representatives of all interests concerned Avitli this code.

Aeronautical Safety Code.

A Sectional Committee has been organized to cooperate with the

Bureau and the Society of Automotive Engineers in the develop)-
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 81

ment of an Aeronautical Safety Code, which will include the requirements for airplanes, balloons, landing fields, etc., and will specify

the qualifications for aviators and the traffic rules to be observed

in the navigation of the air. A preliminary draft of such a code has

already been prepared.

GAS ENGINEERING.

Gas-Appliance Investigations.

The principal activity of the gas engineering section during the

past year has been the continuation of the investigation on gas

burners. A great deal of laboratory work on this subject has been

carried on, and the results of the first part of the work are reported

in Technologic Paper 193, " Design of Atmospheric Gas Burners,"

now in press. The application of these fundamental data was made

in an investigation conducted during the latter part of last summer

in Pittsburgh, the results having been published recently by the

Natural Gas Association in a pamphlet entitled, " Plow Natural Gas

Burners Can Be Improved." A great deal of interest has been

exhibited by the manufacturers of gas appliances, gas companies,

and consumers in the results of these investigations, and it is hoped

that this work will stimulate the designing of more efficient appli- ances and will assist in showing how gas appliances can be adjusted

to give the very best conditions for high efficienc3^

At the Natural Gas Association Convention in Cincinnati in May

the gas engineering section had charge of a very elaborate exhibit,

showing the most efficient methods of utilizing natural gas, together

with the best type of burners to use. This exhibit created a great

deal of interest, and the Bureau has received many requests to continue and expand its Avork of this character.

In connection with the appliance investigations laboratory studies

have been carried out relating to methods of determining small

quantities of carbon monoxide in the products of combustion from

gas burners. This is an extremely important matter, and the Bureau

hopes that with the apparatus and methods now being tried out this

problem will be solved.

Gas-Service Inspections.

The Bureau has received during the past year numerous requests

from public service commissions and municipalities for investigations of gas service, but the lack of men and funds to carry on outside work has made it impossible to do very much along this line.

An investigation was made of the gas-service conditions at Atlanta,

Ga., where it was found that the principal difficulty was lack of

necessary equipment to make enough gas and distribute it properly.

The Eailroad Commission of Georgia consequently permitted an in- crease in the price of gas to allow the company to install the facilities

required. This increase was very strongly objected to by the citizens

of Atlanta, but it appears that the action of the commission was justified, since a recent valuation of the gas company's properties and an

investigation of the operating costs has- shown that a higher rate was

necessary.

64984—21 6
82 REPORT or DIRECTOR OF BUREAU OE STANDARDS.

Another investigation of gas-serA'ice conditions was made in Columbia, S. C. The Bureau's report in this case settled a number of

questions that were in controversy between the city and the gas company.

Investigation of the Cost of Manufacture and Distribution of Gas:

in the District of Columba.

By an order of Congress an exhausti-\-e investigation of the cost of

manufacture and distribution of gas in the District of Columbia

was made and a report rendered to Congress. The results of the investigation showed that the cost of supplying the United States and

District of Columbia Governments was not materially lower than the

cost of sui^plying the private consumers. A slightly lower rate to

the Government is justified by the larger consumption per meter

and the somewhat better load factor. The street-lighting contract

was found to be a source of considerable loss to the company, which

has to be made up by higher gas rates to the general public. This

report has received ver}^ favorable consideration by the gas companies of the country, especially the Bureau's recognition of the fair- ness of the service charge, in which everyone is interested at the

present time.

Cooperation with the California Railroad Commission.

The California Railroad Commission is directing the work of the

Joint Gas Investigation Committee of the State of California, which

is investigating the cost of manufacture and the relative usefulness

of different qualities of gas. This work has been carried on during

the past year and is to be continued during next year. Because of

the fact that the opinions of the Bureau with regard to the second

question are rather definitely on record the California commission

did not extend to the Bureau a formal invitation to join in this investigation, but considerable information which will be of benefit

in the work has been given them. A representative of the Bureau

spent some days with the engineer in charge of the investigation,,

going over all the plans for the work and gi^ang him the benefit

of the Bureau's experience in similar work.

National Gas Safety Code.

Considering the small amount of time available for this Avork

during the past year, the progress on the Gas Safety Code has been

very satisfactor3^ The Bureau has placed in the hands of the joint

sponsor, the American Gas Association, the first five parts of the

code. The gas association has been actively cooperating in this undertaking, and it is hoped that before the end of the current year

the parts 1 to 5, inclusive, of the code will be ready for publication in tentative form.

ELECTRICAL AND RELATED SERVICE STANDARDS.

Standards for Electric Service.

For some years the Bureau, has been studying the questions arising

in connection with the formulation of specifications for electric light

and power service and the technical and engineering requirements

that should be embodied by municipalities or by State public utility
REPORT OF DIRECTOR OF BUREAU OF STANDARDS 83

commissions in the ordinances and lailes and regulations promulgated

mk hj them. Public service commissions in 35 States and in the District

of Columbia are empowered by law to ascertain and fix or prescribe

adequate and reasonable standards for the measurement of quality

and other conditions pertaining to the service rendered by any public

utility and to prescribe reasonable regulations for examination and

testing of such product or service and for its measurement.

The Bureau's Circular 66, " Standards for Electric Service," covers

the field of electric service. This circular contains suggested rules

for adoption by State commissions, three model ordinances for the

use of cities in States where no commission exists or where cities have

regulatory povi^ers in addition to the State commission, and a complete and exhaustive digest of all rules and ordinances in force. Since

the publication of the circular many State commissions have used the

Bureau's proposed rules as the basis for their regulations. A revision

of the circular has been practically completed, bringing it up to date,

by including the State laws and rules adopted since the first edition

was issued and enlarging and extending the discussion of the engineering features of electric service regulation, particularly in relation

to the measurement of demand and power factor. The new laws and

revisions of rules have been collected and will be included in the new

edition, which will be an exhaustive summary of the technical and

engineering features of electric-service regulation. The circular will

be republished during the coming' fiscal year.

In the work of revision the Bureau has greatly profited, as formerly, in the original preparation by the cordial cooperation and

assistance of the public service commissions, municipalities, and public service corporations, the National Electric Light Association, and

the Association of Edison Illuminating Companies.

Standards for Heating Service.

Central station heating, either by hot water or by steam, is technically very closely related to electric central station operation, and

in 1918 a study of the requirements of central station hot-Avater

|i heating serA'icc was undertaken at the request of the Public Service

Commission of Indiana. 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 continued its studies of the engineering factors

entering into the quality of central-station heating and has the

manuscript of a circidar on standards for central-station heating

partially completed. This contains summaries of regulations so far

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, en- gineering 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
84 EEPOET OF DIRECTOR OF BUREAU OF STANDARDS.

special committee of the National District Heating Association and

other associations and engineers interested in central-station heating

problems.

Standards for Water Service.

Water service is largely furnished by municipalities, there being

only a few cities that do not own their waterworks. Many of the

smaller urban communities are, however, served by privately OAvned

plants. A number of the public regulating bodies have adopted

rules for Avater service, and there has been some demand for a publication by the Bureau for water service, similar in scope and purpose

to the circulars on standards for gas service, for electric service, for

telephone service, and for heating service.

The preparation of a circular on water service has, therefore, been

undertaken, and a considerable amount of material collected. Field

work must, however, be clone and engineering studies made before

the material can be published. As in all the Bureau's public utility

work, the full cooperation of the water utilities, municipalities, city

managers, and others interested is obtained before results are made

public.

Engineering Standardization Directory,

The Depai'tment 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. Nearly 200 societies and

organizations have cooperated in the preparation of this list, and

manjf requests for copies have already been received from Government departments and engineering organizations.

TELEPHONY.

Telephone Service Studies.

The fundamental j)roblem underlying the .work of the Bureau on

standards for telephone service is to define " service " in such a manner that both its quantity and quality can be made susceptible to

measurement. It is of the greatest importance both to the utility

and to the public it serves that there be an explicit mutual basis

of agreement relating to the amount and quality of service sold by

the one and purchased by the other.

An essential prerequisite to work in this field is a detailed technical

knowledge of the instrumentalities and methods employed in rendering the service, including their capabilities and limitations, as well

as a thorough understanding of the basic scientific and engineering

principles underlying the whole.

For seA^eral years the telephone section has been applying itself

to the study of the whole intricate subject of telephony with the

purpose of ultimately determining how the many elements that go

to make up telephone service as a whole can be adequately measured.

With this end in vicAv, detailed studies have been made of telephone

systems in operation in this country. The ever-increasing demand

for telephone service and the increase in the cost of labor and mate-
BEPORT OF DIRECTOK OF BUREAU OF STANDARDS. 85

rials require that special consideration be oriven to labor-saving

equipment. The improved manual systems, the semiautomatic, and

the automatic switching systems have for these reasons received the

most attention. Early in the last fiscal year studies were begun on

the " panel type " machine-switching system, so called to distinguish

it from the step-by-step automatic system. In this work the Bureau

has had the cooperation of the American Telephone & Telegraph

Co., which has kindly supplied both drawings and descriptive material. Panel-type equipment is now being installed in some of our

large cities. Detailed studies of this system are therefore essential

to the successful prosecution of the telephone work as a whole.

The foreshadoAvecl extensive replacement of manual switching

equipment by automatic or machine switching equipment, together

with the fact that many exchanges will undergo piecemeal conversion,

has resulted in special attention being given to the interlinking of

the two types of equipment.

Methods of operation, the handling of traffic, the underlying

theory of transmission, transmission measurements, and the testing

of apparatus and equipment have also been the subjects of particular

study. Based on these studies, the preparation of a circular on Telephone Service was undertaken. About the beginning of the last

: fiscal year mimeographed copies of this circular were submitted to all

i State utility commissions, to the telephone interests, operating and

i manufacturing, and to a number of telephone engineers for comment

and criticism before final revision for printing. Considerable re- vision and consequent delay of publication naturally resulted. In

I addition, further delay was occasioned by the incorporation of a

I description of the panel-type system. This necessitated first making

I a thorough study of the electrical, mechanical, and operating prinij ciples involved.

! No attempt was made in this publication to define standards for

telephone service. An effort has been made, however, to give the

reader an understanding of what is involved in rendering telephone

service. Although much of the material relates more specifically

to the subject of telephone practice, it serves as introductory material

for a section on the Principal Elements of Telephone Service. The

primary object has been to furnish the reader with the elementary

knoAvleclge necessary to an intelligent understanding of the material

now being prepared for a circular that will treat in considerable

detail of telephone service, its grade and grade elements.

j The circular on Telephone Service, No. 112, for which there has

already been evidenced a very considerable demand, will be ready

for distribution early in the new fiscal year. In its preparation the

, Bureau has had the cordial and helpful cooperation of the telephone

interests and of a number of individual engineers and teachers.

I Other Telephone Problems.

j The manuscript of the proposed circular on telephone transmisI sion, mention of which was made in the last annual report, is undergoing extensive revision and enlargement. It is hoped that it may

j be published some time during the coming fiscal year.

A paper dealing with the electromechanics of the telephone rej ceiver is in course of preparation. This will treat of the theory of

j the receiver, with and without eddy current losses, motional im-
86 REPORT or DIRECTOR OF BUREAU OF STANDARDS.

pedance circles, electromagnetic j)roperties, motional constants, and

efficiencT.

Laboratory work in telephony was confined primarily to work on

receivers, part of which was in cooperation with the radio section

of the Bureau on radio receivers and part was experimental work in

connection with the last-mentioned paper.

The Bureau has continued to cooperate with the Standards Committee of the American Institute of Electrical Engineers, through its

subcommittee on telephony, telegraphy, and radio, in the standardization of technical terms employed in telephony.

GENERAL CONDITION OF THE DIVISION.

During the year it has been necessary to continue the gradual re- duction in the staff of the division which has been going on for the

past two years. The total personnel of all classes assigned to the

work of this division was 163 at the close of the fiscal year, June 30,

1919, US in 1920, and 128 in 1921. Fortunately, this reduction in

numbers has been in part compensated for by a notable increase in

the stability of the stafi'. The statistics given last j-ear showed that

61 per cent of the statf had then been in the division less than two

years and 31 pev cent less than one year. Since that time there have

been relativeh' few new appointments, so that the average length of

service of those remaining is practically a year greater than it was

then. This improvement brings the double advantage that the newer

members of the staft' have become more useful, and that the older

men have been in part relieved of the necessity of instructing a suc- cession of inexperienced assistants. It is believed, therefore, that on

the whole the current output of work has increased rather than decreased during the year.

PUBLICATIONS.

The following papers relating to the work of the division have been

published during the year

Testing of magnetic compasses (R. L. Sanford), B. S. Sci. Paper No. 382. Measiu'ement cf hysteresis values from high magnetizing forces (W. L. Clieney), B. S. Sci. Paper No. 383. The variation of residual induction and coercive force with magnetizing force

(R. L. Sanford and W. L. Cheney), B. S. Sci. Paper No. 384. The two common failures of the Clark standard cell (E. C. McKelvy and M. P. Shoemaker). B. S. Sci. Paper No. 390. The measurement of diffuse reflection factors and a new absolute reflectometer

(A. H. Taylor), B. S. Sci. Paper No. 391. Magnetic reluctivity relatiouship as related to certain structures of an eutectoid

carixm .steel (C. Nusbaum, W. L. Cheney, and H. Scott), B. S. Sci. Paper

No. 404. A simple portable instrument for the absolute measiirement of reflection and

transmission factors (A. H. Taylor), B. S. Sci. Paper No. 40-5. Effect of the rate of cooling on the magnetic and other properties of an annealed

eutectoid carbon steel (C. Nusbaum and W. L. Cheney), B. S. Sci. Paper

No. 408. Automatic apparatus for intermittent testing (G. W. Vinal and L. M. Ritchie), B. S. Tech. Paper No. 171. OsciliogTaph measurements of the instantaneous values of current and voltage

in the battery circuit of automobiles (G. W. Vinal and C. L. Snyder), B. S. Tech. Paper No. 186. Standards for gas service, fourth edition, B. S. Circular 32. The operation and care of vehicle type batteries, B. S. Circular No. 92.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 87

Telephone service, B. S. Circ. No. 112. National safety code for the protection of the heads and eyes of industrial

workers, B. S. Handbook No. 2. National electrical safety code, B. S. Handbook No. 3. Discussion of the rules of the national electrical safety code, B. S. Handbook

No. 4. Station performance during Bureau of Standards American Radio Relay League

tests of June and July, 1920 (S. Kruse), QST, 4. September, 1920.

The Bureau of Standards—American Itadio Relay League tests of short-wave

radio signal fad.ag (S. Kruse). QST, 4, November and December, 1920.

Radio signal fading phenomena (J. H. Dellinger and L. E. Whittemore), Jour. Wash. Acad, of Sci., 11, p. 245, June 4, 1921.

The distributed capacity of inductance coils (G. Breit), Phys. Rev., IT p. 649, June, 1921.

The precision of photometric measurements (F. K. Richtmyer and E. C. Crittenden), Jour. Opt. Soc. of Amer., 4, p. 371, 1920.

Radio communication.—Elementary explanation of the principles of radio

telegraphy and telephony (J. H. Dellinger), Sci. Amer. Monthly, p. 157, February, 1921 ; also. Radio News, 2 p. 6TS. April, 1921.

The raciio work of the Department of Commerce (J. H. Dellinger), QST, 4, June, 1921.

Blindfold navigation.—By radio (F. A. Kolster), Shipping, 13, Feb. 25, 1921.

Radio connnunication with postal aeroplanes (J. L. Bernard and L. E. Wliittemore), Aerial Age Weekly, 13, pp. 105, 127, 155. Apr. 11, IS, 25, 1921.

Review of radio telephony (J. H. Dellinger), Electrical World, Jan. 15, 1921.

Measurements on audio-frequency amplifiers (L. M. Hull), Wireless Age, 8,

p. 12, June, 1921.

The catliode-ray o.scillograph and its applications in radio work (L. M. Hull),

Proc. Inst, of Radio Engineers, 9. p. 130. April, 1921. Safety to life (M. G. Lloyd), Electrical Inspector, p. 8, December, 1920.

The need for a national logging and sawmill code (J. A. Dickinson), Safety

Engineering, December, 1920.

Standardization and safety (C. E. Oakes and J. A. Dickinson), American

Machinist, July 1, 1920.

Memorandum on the execution of Italian semirigid airships observed at the

front (A. Halsted), Air Service News Letter, 5, No. 8, Feb. 26, 1921;

also in Aviation and Aircraft Jour. 10, No. 11, p. 341, Mar. 14, 1921.

How natural gas l)urners can be improved (I. Y. Brumbaugh and G. B. Shawn),

Natural Gas, May, 1921.

The following papers are in press

Power factor of polyphase systems (F. B. Silsbee), pre.sented before the American Institute of I^lectrical Engineers, to appear in transactions of Am.

Inst, of Elec. Eng., 1920.

Standard specifications for large incandescent electric lamps, ninth edition, B. S. Cir. No. 13. Some ma.ior problems in photometry (E. C. Crittenden and J. F. Skogland),

to appear in Journal of Optical Society of America.

Atmospheric corrections for the Harcourt standard pentane lamp (E. B. Rosa,

E. C. Crittenden, and A. H. Taylor), to appear in Journal of Optical Society

of America.

Electrolytic corrosion of lead by continuous and periodic currents (E. R. Shepard), to appear in Transactions of American Electro-Chemical Society, 1921.

Design of atmospheric gas burners (W. JI. Berry, I. V. Brumbaugh, G. F. Moulton, and G. B. Shawn), B. S. Tech. Paper No. 193.
88 REPORT OF DIRECTOR OE BUREAU OF STANDARDS.

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 heat and temperature samples; industrial applications of heat and temperature measurements; de- termination of fundamental engineering data involving thermal constants; determination

of the fire-resistive properties of structural materials; investigations relating to auto- motive power plants, fuels, and lubricants. THERMOMETRY.

This section is concerned Avith researches on the standard scale of

temperature and thermometric fixed points from tlie lowest attainable temperature up to about 500° C. ; maintenance of working

standards within the above range; methods of standardizing temperature-measuring instruments, such as liquid in glass thermometers,

vapor-pressure thermometers, resistance thermometers, thermocouples; the testing and certification of temperature-measuring instruments; and methods of measuring temperatures.

Clinical Thermometers.

The number of clinical thermometers tested during the year,

26,336, is only slightly larger than the number tested in previous

years. The change in the character of the thermometers tested is,

however, a notable one, since over 95 per cent of the thermometers

tested during the year were for veterinary use. One State government submitted for test during the year 2,570

veterinary clinical thermometers and 12 thermometers for human

use.It is a remarkable commentary on the appreciation by medical

men of accuracy in a clinical thermometer, one of their most important instrument of diagnosis, when it is pointed out that the

Bureau was called upon to test over 20 times as many veterinary

thermometers as thermometers intended for use in connection with

human beings.

It should not be infei'red, however, that the question of accuracy

in thermometers intended for human use has been entirely neglected.

It is at least encouraging to note that the manufacturers of clinical

thermometers have taken a greater interest in the accuracy of their

product as shown by the considerable number of their standards

submitted for test, as well as by their efforts to improve the quality

of their product by other means referred to below. By providing

a uniform and accurate temperature scale which can be used by

the manufacturers in graduating their product, the Bureau is able

to assist in insuring that a large part of the product Avill be satisfactory, although no means of preventing the sale of defective or

inaccurate thermometers is provided. One State and one municipality have adopted regulations to control the accuracy of clinical

thermometers sold within their respective territories.

In extenuation of this apparent lack of appreciation of accuracy

in clinical thermometers it is only fair to add that medical men have

become accustomed to rely on the makers' and jobbers' certificates

which ai-e generally furnished with every instrument sold. While

it is true that some of these certificates issued by the more reliable
KEPORT OF DIRECTOR OF BUREAU OF STANDARDS. 89

makers are quite trustworthy, it is nevertheless a fact that vast

numbers of certificates found on the market are unreliable, and where

the accuracy of such certificates has been checked in the laboratories

of the Bureaii it is quite often evident that they do not at all represent the results of any actual tests, but were merely filled out in

the issuing office with all zero corrections.

Two important conferences relating to clinical thermometers were

held at the Bureau during the year. At one of these conferences,

called at the request of several of the largest manufacturers, the

questions discussed related to test requirements which a reliable

clinical thermometer should satisfy. Very satisfactory conclusions

were arrived at in all of the many technical questions involved.

The second conference was called at the request of the American

Clinical Thermometer Manufacturers' Association for the purpose of

discussing with the Bureau the qiiestion of asking for national

legislation requiring the official testing of all clinical thermometers

offered for sale in, or for export from, the United States. The compulsory testing of all clinical thermometers made in Great Britain

for either domestic or export purposes is required, and a similar

procedure is followed in France and was then under consideration

by Germany, which has since adopted it. As a result of this con- ference the Bureau submitted to the aforesaid association a preliminary draft, of a " model " law embodying the combined views

of the Bureau and of those representing the association at this conference. Further consideration of this important question is now in

the hands of the association..

Of the 26,336 clinical thermometers submitted for test 91.2 per

cent, or 24,011, were certified, showing a marked improvement in

the quality of the product submitted this year in comparison with

that of last year, when the percentage certified was 85.5. Of the

thermometers submitted 0.2 per cent were received broken and 0.2

per cent were broken in test, 1.8 per cent were rejected for obvious

defects in construction, 1.2 per cent because their index was too

difficult to throw back, 1.6 per cent because the index "retreated."

The remainder, 3.8 per cent, was rejected because the correction

found in the test exceeded the tolerances that have been adopted for

the certification of thermometers of this type.

Laboratory Thermometers.

Partial Immersion Tkermometers.—In a note on total and partial

immersion thermometers published in the March (1921) issue of the

Journal of Industrial and Engineering Chemistry the advantages of

using partial immersion thermometers in many ordinary laboratory

temperature measurements was pointed out, and attention was also

called to the fact that in some cases the use of partial immersion

thermometers would be disadvantageous.

Speci^.cations for Laboratory Thermometers.—After consultation

with members of the American Chemical Society's Committee on

Guaranteed Eeagents and Standard Apparatus specifications were

prepared for three chemical thermometers, which appeared to be

sufficient for almost all ordinary temperature measurements commonly required in the chemical laboratory. Two were partial-immersion thermometers, graduated in single degrees from —20 to
90 EEPOET OF DIKECTOE OF BUEEAU OF STANDARDS.

+150° C, and from —10 to +360° C, respectively, while the third,

intended for more accurate measurements, is graduated from —5 to

+105° C. in 0.2° intervals. These specifications were published by

the chairman of the committee referred to in the March (1921) number of the Journal of Industrial and Engineering Chemistry and

have been recommended by that committee for adoption by the

American Chemical Society. The specifications have been used by

the Bureau of Standards in the purchase of a considerable number

of thermometers and have also been adopted by the General Supplj^

Committee.

lYeio Edition of Circular on Testing of T'herv%oineters.—The previous edition of this circular contained in addition to testing regulations much general information on thermometry and temperature

measurements. The neAV edition contains only information essential

to applicants for tests, together with testing reg-ulations and fee

schedules. A new feature is the inclusion of tables of tolerances for

thermometers of various types and ranges. Thermometers Avhich are

free from defects and which are correct within the tolerances may

be certified, while thermometers not complying with the requirements will receive a report giving the results of the test and the rea- son why certification was refused. This circular is in press.

Treatise on Thermometry.—The general information on thermometry which was included in the prcAdous edition of the circular

referred to above is to be incorporated, together with much new material embodying the experience of the thermometric laboratory during the past 10 A'ears in a scientific paper now nearing completion.

This paper is to loe published under the title " Thermometry."

Nexo Certificate For7?is.~—Nevf certificate forms and stem correction

sheets, which are believed to represent a considerable improA^ement,

were prepared during the year, and the p)rinted forms should be

available early in the coming year. The number of separate forms

required has been reduced.

Thermometer Testing Equij^ment.—Taa^o ncAV thermometer comparators, one a large electrically heated Avater bath and the other a small oil bath for testing short total immersion thermometers, were

installed during the year. The former, Avhich is large enough to

permit the simultaneous comparison of 24 thermometers, has greatly

facilitated the work of testing. The apparatus in the laboratory has

been rearranged, and seA^eral features designed to facilitate the work

-of testing haA'e been added.

Thermometer Testing.

While the section has not been able to do its testing as promptly

as is desirable, there has been a marked improvement in this respect

during the past ^-ear. Thus, on July 1, 1920, there were on hand

awaiting test in the thermometric laboratories 73 tests, including

766 thermometers, Avhile on July 1, 1921, there Avere on hand 46 tests,

including 288 thermometers, representing ari'ears of about one month's Avork. This result has been accomplished with a someAvhat

decreased personnel, depleted by frequent resignations, and notwithstanding that the demands on the section for testing during the

year haA'e greatly exceeded that of any pi-eceding year. This result,

hoAvever, Avas not accomplished without some serious sacrifices. The

heavy demands for testing have made it impossible for the ther-
KEPOET OF DIRECTOR OF BUREAU OF STA^TDAEDS. 91

mometric section to devote any time to researches having an important bearing on the work of the section. Several important investigations relating to thermometry, the establishment of the temperature scale, and the measurement of temperature have had to be

discontinued. A moderate increase of personnel would enable this

section again to take up these important researches and at the same

time would insure greater promptness in the return of apparatus

sent to these laboratories for test. The tests completed during the

year are summarized under the caption, " Thermometer, Pyrometer,

and Heat Tests."

Platinum Resistance Thermometers.

A paper describing in considerable detail the methods used in the

construction of precision platinum resistance tliermometers of the

standard and calorimetric types was published in the Journal of

the American Chemical Society and also as Bureau Scientific Paper

Xo. 407. Considerable improvements in the calorimetric thermometer have resulted in simplifying its construction and reducing

its fragility.

It had been known for a number of years that the fundamental

comstants for a calorimetric thermometer differed somewhat from

those of a standard thermometer made from the same kind of wire.

It was definitely proven that the difference was due to strains in

the winding of the calorimetric thermometer, and a method of

annealing was devised to relieve such strains. The constants of calorimetric thermometers so treated are found to be substantially the

same as those of thermometers of the standard type, thus removing

a possible objection to the establishment of a standard scale of temperature by means of the platinum resistance thermometer.

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 pja'ometers, including absorption glasses and color screens,

radiation pyrometers, etc. ; physical properties of materials at high

temperatures, such as emissivity, monochromatic and total, specific

heats, melting points of refractories, metals, fire brick, etc., ionization and radiation in gases and vapors, etc. ; industrial pyrometry

and the measurement of the temperatures in industrial processes

and the annealing of glass.

Industrial Pyrometry.

At the symposium on pyrometry held at Chicago in September,

1919, under the auspices of the Pyrometer Committee of the National

Research Council and the American Institute of Mining and Metallurgical Engineers, nine papers were presented by members of the

pyrometry section of this Bureau. The collected papers and discus-
92 EEPOET OF DIRECTOR OF BUREAU OF STANDARDS.

sions have been published by the institute as a book of 700 pages,

containing 60 separate papers by various authors. The great demand

for this book among the technical industries has emphasized the importance of pyrometr}^, the proper application of which is requisite

in all industries using processes involving temperature control.

With the extensive pja'ometric installations noAv in operation in our

industries, especially for the heat treatment of steel, locomotive and

motor vehicle parts, springs, forgings, tools, annealing and vForking

of nonferrous metals, manufacture of ceramic materials, etc., the art

of pyrometry has made remarkable strides. From the days when

temperature was estimated by visual observation to the present time,

in which a central pj'rometer station of a modern plant is nearly as

intricate as a telephone central station, has been a period of but a decade. The introduction of automatic and semiautomatic distant

temperature control, temperature recording devices, signal systems,

etc., has enabled the manufacturer to produce a more uniform and

better product with comparatively fewer failures and losses.

In spite of this rapid development of pyrometry no manual describing the use of instruments, methods of procedure, installations

for various purposes, calibration, and upkeep of apparatus had been

written. At the request of many manufacturers the Bureau undertook the preparation of such a manual and has issued as Technologic

Paper No. 170, a book of 326 pages with 187 illustrations, treating

these subjects from the practical standpoint. The first edition of

2,000 copies was exhausted two months after publication and is now

being reprinted. Large manufacturers have purchased copies for

their technical employees, and several universities have adopted the

work as a standard textbook. The book is based on the 20 3?ears' ex- perience of this Bureau in meeting problems arising in the industrial

application of the science of pyrometry.

Standard Samples for Thermometric Fixed Points.

The Bureau issues samples of various metals, the melting or freezing points of which have been determined with high precision. By

this means the standard temperature scale of the Bureau may be distributed to the various technical laboratories. The demand for these

samples has been much greater than was at first expected, and metal

is now procured in half-ton or ton lots. A new allotment of zinc was

standardized this year, but both zinc and aluminum samples are

practically exhausted at the present time. A considerable stock of

copper and lead is still available.

Research in Pyrometry.

The Standard High^Tempei-ature Scale.—Work is being con- tinued on the more precise determination of the fixed points on the

high-temperature scale. Eedetermination of the melting point of

palladium is now in progress. The purity of the best samples of

palladium obtainable has not been satisfactory^, and the Bureau has

now produced palladium of greater purity than heretofore securable.

The optical system of the disappearing filament optical pyrometer

used for the temperature measurements has been carefully investigated, and by proper diaphragming the effect of diffraction around

the filament is eliminated. This has increased the precision of a

setting so that temperatures in the neighborhood of 1,500° C. may
KEPOKT or DIRECTOR OF BUREAU OF STANDARDS. 93

be measured with a precision of 0.2° C. Specially constructed pyrometer lamps having plane parallel faces fused on by the process

described below have greath^ assisted in this work.

The globe of the lamp is made from a short section of glass tubing

to which are fused fiat circular plates of glass. During the process

the glass is maintained at a carefully controlled temperature, the

annealing temperature of the particular type of glass employed.

The cover plates are put in place and fused to the tube by means of

a minute, oxygas flame. This process makes a perfect joint with no

distortion of the surfaces. The glass lamp is then annealed and

slowljr cooled to room temperature. This process may be used for

the manufacture of numerous glass articles where cemented surfaces,

ordinarih- employed, are unsatisfactory. For example, glass cells

for acids and other corrosive liquids, hollow glass jorisms, colorimeter parts, etc. A description of the method was published in the

Journal of the Optical Society of America, 4 p., 496; 1920.

Life Tests of Rare Metal Thermocouples.—The most widely used

instrument for the industrial measurement of very high temperatures is the XDlatinum platinum-rhodium thermocouple. It was noticed that some of these couples suffered appreciable changes in

electromotive force, due to heating for the short period required for

their standardization. At the request of several manufacturers of

pyrometers an investigation was undertaken to determine the magnitude and causes of the changes in the indications of these couples

due to long continued exposure to high temperatures, under conditions where the couple is protected from contamination b}^ suitable

protecting tubes and the avoidance of reducing atmospheres.

The two makes of this type of couple which are on the American

market are of American and foreign manufacture, respectively. It

was found that the foreign alloy wire contained a considerable

amount of iron as an impurity, and the platinum, as well as the

alloy from both sources, contained traces of calcium and copper.

The changes in the indications of the couples traceable to impurities

in the platinum wires were very small for both makes of couples.

The impurities in the foreign alloy wire, however, were observed

to cause large changes in the indications of the couple. The information resulting from this investigation has been given the manufacturers, and it is believed that better thermocouples will soon be

generally available. In cooperation with the Chemistry Division

thermocouple wire of higher purity than has been obtainable elsewhere has been produced.

Heat Treatment of Glass.

In cooperation with the Optical and Ceramics DiAdsions the investigation on annealing temperatures and methods of annealing

glass for the removal of strains and certain inhomogeneities which

produce warping, variations in the refractive index, and double re- fraction, is being continued. Data are thereby being obtained on

the condition of the glass when it has been annealed according to the

different methods in practice or which have been proposed. These

data include measurements on the strain left in the glass, on its performance in and suitability for optical instruments, and on such

changes in its physical properties as may be produced by the annealing. Similar investigations are also in progress on ordinary glasses
94 EEPOBT OF DIRECTOE OF BUBEAU OF STANDARDS.

such as those used in glassware, etc., where the strains must be re- moved in order to prevent spontaneous breakage. Papers on certain

phases of these inA^estigations are in preparation, and one paper was

published this year.

Proper furnace construction and temperature control are very es- sential in annealing glass, and the investigations on the degree of

temperature uniformity and accuracy of control required while an- nealing and cooling the glass are being continued. Results indicate

that in practice much time is still being wasted in annealing, especially in the case of ordinary glass.

The methods employed in " hardening " or toughening glass are

also being studied. This process is the reverse of annealing and

renders glass unfit for optical purposes, while by introducing properly distributed strains makes it much more resistant to mechanical

shock. Such glass is valuable for protective goggles, windows, etc.

Investigation in Electronics.

The study during the past decade of the emission of electrons from

hot wires has led to several most important and unexpected scientific

discoveries of immeasurable value to humanity, as, for example, the

Coolidge X-ray tube, amplifiers for transcontinental telephony and

wireless telegraphy and telephony, rectifiers, etc. These practical

devices have been the outcome of pure research directed especially

for the purpose of obtaining more information as to the structure of

the atom. It is reasonable to predict that by the continuation of such

investigation more devices of benefit to human welfare will be develojoed and methods will arise whereby our economic efficiency may

be increased, as woidd be the case, for example, if a more efficient

form of illumination should resiilt. It is further safe to predict

that a radical improvement over the present form of electric lamp,

itself most inefficient, can be only the result of pure research in the

subject of atomic structure. The great electrical companies realizing

this fact are devoting vast sums of money to pure research in this

field. The Bureau, on account of the limited funds available for

such work, can hope to contribute in only a small measure to the

knowledge of atomic structure now so rapidly increasing. It is, however, necessary to keep in constant touch with this branch of physical

investigations, on account of the extreme importance of its applications. The work on collisions of electrons and atoms reported last

year has been continued, and seven papers bearing upon certain

aspects of atomic structure and the mechanism whereb^^ light and

radiation are produced in electric arcs have been published. Three

other papers are to appear at an early date.

HEAT MEASUREMENTS.

Measurements are made in this section over a wide range of temperatures of thermal proj^erties 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 fueJs; heat transmission and thermal conductivity.

Work is also done on the development of calorimetric apparatus and

methods and on metliods for temperature control, pressure measurements, measurement of heat transmission, etc.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 95

Practicall}' all of the research work of this section during the year

has been devoted to the determination of those fundamental phj'sical

constants of materials which find application in refrigeration engineering.

Refrigeration Constants.

Work was continued on the determination of the fundamental constants of refrigeration engineering, an investigation which has been

in progress for some years and which Avas undertaken at the request

of the American Society of Eefrigerating Engineers. This work

was continued with a considerably reduced staff necessitated by the

decreased appropriations available. The situation was somewhat re- lieved by the action of the society referred to who manifested their

great interest in the continuance of this work by assigning to the

Bureau two research associates to work on these problems.

A report covering all the Avork completed to elate was submitted

to the December meeting of the American Society of Refrigerating

Engineers. This report included the first half of the new Bureau

of Standards tables on the thermodynamic properties of ammonia,

namely, that portion of the table relating to the saturated liquid

and A^apor. This report has been published in the journal of the

society.

A paper giving the results of determinations of the specific a^oI- umes of anhydrous liquid ammonia in the interA'al —78 to 100° C.

was published in the Journal of the American Society of Eefrigerating Engineers, and a Bureau Scientific Paper on the same subject is

in press.

Specific Volume of Saturated Ammonia Vapor.—All of the ex- perimental data relating to the specific A'olumes of saturated ammonia vapor in the interA-al —50 to -|-50° C. were obtained last year.

The results have not yet been prepared for publication oAving to the

absence this year of a member, of the staff. On his I'eturn early

next year the preparation of these results for publication will be

resumed.

Specific Volumes of Superheated Vapors.

The completion of the tables of properties of anhydrous ammonia

will require experimental data on the specific A'olumes and the specific

heat of the superheated vapor. The measurements of the pressureA'olume-temperature relations for the superheated vapor are to be

made by the well-knoAvn constant A'olume gas thermometer method.

The construction of the special bulbs, manometers, thermoregulatecl

baths, etc., has been completed and a few preliminary measurements

haA'e been made, Avhich appeared to be sufficient to indicate what

sources of error Avill require special attention in order to reduce their

effects to the necessary extent.

Some measurements of the specific A'olume of superheated ammonia vapor by another method, which involves the measurement of

the refractive index of the vapor, haA'e been completed.

Specific Heat of Gases.

The flow calorimeter designed for determinations of specific heat

of gases has been completed, installed for operation, and preliminary

experiments made to test its performance. This process of assembling
96 EEPOET OF DIRECTOR OF BUREAU OF STANDARDS.

has progressed slowl}- on account of the complicated construction

necessitating tests at various stages to insure both the necessary

rnechanical strength and integrity, and also the integrity and insulation of the numerous electrical circuits.

The accessory apparatus for operating the instrument is quite

elaborate. It includes three thermoregulated baths which separately

control the temperature of the instrument, the feed gas supply, and

the condenser for collecting the used gas when this can be done.

There is also a pressure regulator automatically operated for insuring a steady flow of gas, an orifice flow meter for observing the con- stancy of floAv, and a vacuum pump for evacuating the gas lines,

detecting leaks, and also for evacuating the calorimeter envelope in

order to minimize the loss of heat by conduction. Mercury manometers for low and a piston gauge for high pressures indicate the pres- sure of the gas subject to specific lieat determination. Temperature

measurements are made electrically both by resistance thermometers

and by thermocouples.

Ihe preliminary performance tests mentioned above have been

quite satisfactory and indicate that the control of the heat losses in

the instrument is such as to permit a net accuracy in specific heat

determinations comparable with the precision of the various observed elements which enter into the final result. This net accuracy

is ample for the purpose of furnishing data for engineering tables,

which is the primary object of the investigation. The first data to

be sought with the instrument is the specific heat of ammonia gas.

Tliis is required to complete the tables of properties of ammonia for

the use of refrigerating engineers. Only a few minor construction

details remain to be completed before the experimental work with

ammonia can proceed.

Mollier Chart.

The Mollier chart is a graphic representation of the data contained

in a table of the thermodynamic properties of a material, such as steam or ammonia, and in engineering work is much more convenient

to use than the table. It was found that by suitable choice of the co- ordinates a considerable improvement over the customarj^ heat-content-entropy chart could be obtained. A paper illustrated with several figures to show the form the chax't assumes with various coordinates, thus permitting selection of the most suitable chart, is to be

published in the Journal of the American Society of Refrigerating

Engineers.

Pressure-Relief Diaphragms.

Safety deA-ices to relieve the pressure in a closed vessel, such as a

boiler, gas cylinder, etc., are used in large numbers. In connection

with certain investigations dealing with gases under pressure it was

necessary to install a number of very small pressure-relief devices

of this kind. The diaphragm type, consisting of a metal diaphragm

closing an opening in a brass plate, was chosen. It was necessary

to make a number of measurements of the effect of size of opening,

thickness, condition, and material of diaphragm, etc., on the bursting pressure before designing the safety devices which were installed.

The data thus accumulated on safety relief diaphragms were collected

and have been published in the March (1921) number of the Journal

of tlie American Society of Refrigerating Engineers.
REPORT OF BIRECTOR OF BUREAU OF STANDARDS. 97

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.

Production of Low Temperatures.

Liquid Air.—The demands for liquid air have increased, and

rather large quantities have been supplied both to other laboratories

of the Bureau of Standards and to institutions outside the Bureau.

Carbon Dioxide.—The carbon dioxide compressor has been operated very frequently, suppljang carbon dioxide to the thermometry

section for thermometer comjDarators, for work on the thermal properties of gases, and for the testing of aviation instruments at low

temperatures.

Liquid Hydrogen.—The apparatus for the production of liquid

hydrogen has been completed, but time available has not permitted

further work with it. Vacuum- Walled Containers.—Investigations have been made of

the influence of various factors upon the rate of heat transfer in

vacuum-walled containers with the expectation of being able to

construct containers of much greater insulating efficiency than those

now in use. This inves^'igation has been frequently interrupted by

other Avork and has not been completed.

Aviation Oxygen A'p'paratus.—At the request of the Air Service

equipment for carrying liquid oxygen in airplanes to supply oxygen

for respiration at high altitudes has been designed and cons*:ructed.

This apparatus is considered to be an improvement over other equipment for this purpose in possessing large capacity for a given weight

and in its reliability and safety. Reports have not yet been received

of its use in flight.

Production of Liquid Air on a Laboratory Scale.

A paper under the above title, giving details of construction of the

Hampson type of Ijquefiers designed and constructed for use in the

low-temperature laboratory, was prepared and submitted for publication as a Bureau Scientific Paper and is now in press. This paper

also contains a general description of the liquid-air plant and its

accessories and was prepared for the information of those contemplating similar installations, since with the exception of the air

comi^ressors the apparatus required for liquefying air can not be

i purchased in this country.

I FIRE-RESISTIVE PROPERTIES OF STRUCTURAL MATERIALS.

I The object of the investigations on the fire-resistive properties of

Ij structural materials is to furnish architects, engineers, builders. State

and city building bureaus, insurance interests, and others with fundamental engineering data relative to the behavior and safety under

fire conditions of the various types of building materials and con6498'!—21 7
98 EEPORT or DIKECTOB OV BUREAU OF STANDARDS.

structions. To this end fire tests of structural materials and structural members are conducted; investigations are made to develop

engineering data relative to the general fire-resistive features of

building construction; tests are made of fire prevention and fireretarding devices ; testing conditions and testing methods are investigated with a view to standardization ; and recommendations are made for jDroper provisions in building codes and fire codes.

Fire Tests of Concrete Columns.

A brief summary of the nature of these tests, which were con- ducted at the Pittsburgh laboratories of the Bureau, together with

some of the more general conclusions, have been given in previous

reports.

Detailed descriptions of the results of this investigation have been

published in the Proceedings of the American Concrete Institute

for 1918. 1919, and 1920. A complete report of the investigation

is to be published as a Bureau Technologic Paper, the manuscript

for which is now nearh^ completed.

Fire Tests of Building Columns.

The Bureau's cooperation in tliis resfearch. wliich comprised fire tests of 106 columns, conducted jointly with Associated Factory

Mutual Fire Insurance Companies and Underwriters Laboratories

(Inc.), was concluded during the year. General notes on the purpose, scope, methods of testing, and summary of important test results have been given in previous reports. The full results of the

in^'estigation were published during the year as a joint organization

report, and also as Paper No. 184 in the Bureau's technologic series.

The report, which contains some 376 pages and numerous illustrations, tables, and curves, contains fundamental engineering data

which it is confidently believed will have an imj^ortant bearing on

fire-resistive building construction. The amount of new data made

available by this report exceeds many times the total amount of

data availalile in this field before the completion of this research.

It is highly desirable that similar data be obtained on other elements

entering into building construction.

Fire Tests of Brick Walls.

Tccts of brick-wall panels, 11 feet high and 16 feet wide, are being made, in the Bureau's testing furnace at Washington. This

is the initial series of a number that it is proposed to carry out with

this equipment, the intention being to include all the wall and partition materials in common use. It Avas deemed advisable to introduce the tests with brick first, because brick is a primary building

material that has been in long and universal use, and the values obtained with each thickness can be used as a standard of comparison

in interpreting the results with other materials. There is at present

much demand for information on the fire values and stability under

fire conditions of brick walls. Opinion as reflected in building

ordinances varies greatly relative to wall thickness requii'ements, and

while this is due in part to considerations other than those relating

to fire, it is thought that a properly planned series of fire tests will

help materially to determine the minimum thickness safe for use.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 99

The panels are built by a masonry contractor at a fixed price per

panel, as determined by competitiA^e bids. The series will include

tests with brick made of two tj^pes of surface clay and one shale,

and also with sand-lime and Portland cement brick. Studies will

be made on the effect of changing the cement and lime content of

the mortar. The panels are either built solidly into their containing frames to approximate conditions of restraint sometimes present

in practice, or they are built free from the sides and top of the frame,

some with stiffening pilasters at the ends to simulate conditions of use in the upper stories of some buildings. Heat is applied to one

side of the panel, using fuel oil atomized by jets of steam or compressed air, and temperatures are measured at a number of points

in the furnace as well as on the exposed and unexposed faces of the

panel and at intermediate points within it. The relative deflections

of j)anel and restraining frame are measured, as also the deflections

of the restraining frame itself. The fire test is continued for six

hours, provided failure does not occur earlier. Water will be applied

in some of the tests after a one-hour fire exposure.

The series will consist of about 25 tests of 8-inch and 12-inch brick

walls of the solid and of the hollow type, of which 9 tests have been

completed. During 1920 the equipment was tested out, and some

changes deemed necessary were made. Two preliminary tests were

made of wood stud and plaster on metal-lath partitions. The work

with the brick panels was done during the last five months of the

fiscal year. A'N^iile too early as yet to give definite conclusions, the

tests indicate that within limits as to height the 12-inch wall is a

stable and effective fire barrier. Relative to the 8-inch Avail, less

definite statements can be made, although under limitations as to

exposure, height of wall, and lateral support, which it is proposed

to establish in this and related investigations, the safe use of the

8-inch wall ma,j possiblj^ become adequateh' defined.

Hollow-Tile Investigation.

Through a cooperative arrangement with the Hollow BuildingTile Association an investigation was begun on the fire-resisti^-e ancl

related properties of hollow-clay tile. Claj^ and hollow tile, representative of the types generally used, are made into specimens for

tension, transverse, compression, absorption, freezing, vitrification,

fusion, and fire tests. For the latter a gas-fired furnace Avas built

in the ceramic laboratory of the Bureau to accommodate panels up

to 3 feet wide and 5 feet high and subject them to working load during the fire test. The panel at present used is 1 foot Avide and consists of 8-inch double-cell tile, with Avhich 26 fire tests have been

made, the results of which are chiefly of value for comparing the

fire-resistive properties of tile made from different claj'S and in different forms. It is proposed to study the effect on fire-resistive

properties of ground-burnt clay (grog) additions to the raw clay in

molding; also of burning to different degrees of hardness.

The auxiliary tests indicate large variability in strength and

elastic properties, and as yet no definite I'elation has been established

between absorption and compressive strength.
100 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Strength of Materials at High Temperatures.

Brief description of an apparatus for determining the compressive

strength and elastic properties of materials as influenced by heat

and notes on results obtained in a preliminary series on structural

steel, concrete, and timber have been given in previous reports.

During the first months of the past year the work on timber, as far as it concerns the present series, was completed, the species tested

being long-leaf pine and Douglas fij-. The equipment was dismantled

in consequence of the transfer of the Bureau's Chicago activities to

Washington and is now being reassembled with improvements in

details that will increase the accuracy of the observations.

Miscellaneous Fire-Resistance Activities.

A room is being equipped for the studj^ of some of the problems

connected with fire-resistance work, including, in addition to the

investigation noted above, ignition points, spontaneous ignition,

porosity, and other auxiliary tests of materials. Some preliminary

work was done on ignition points and susceptibility to ignition. At

the request of the Steamboat-Inspection Service tests were made of

a number of motion-picture projectors relative to the fire hazard

involved in their use aboard ships.

Among other miscellaneous activities a few examinations to determine causes of fire and fire damage have been made. Information

on the fire resistance or fire hazard of materials and devices has been

given in response to requests where it could be done without undue

experimentation or research.

AUTOMOTIVE POWER PLANTS, FUELS, AND LUBRICANTS.

The Avork of this section includes the 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.

The depletion of the petroleum supply of the country and the con- sequent demand for better fuel econom^'^ in automotive transportation

liave led to an increased interest in the results of research in the field

of more efficient fuel utilization. The Bureau has attempted to use its

facilities in such a way as to be of maximum assistance to the industrj^, as well as to prosecute the researches in progress for the military departments of the Government.

Altitude Laboratory.

The altitude chamber of the dynamometer laboratory has been

used for two major purposes: (a) Altitude tests of airplane engines

in cooperation with the Engineering Division of the United States

Army, and (5) an investigation of the effect of compression ratio

on tile performance of aviation engines. Two engines have been

tested in cooperation with the Engineering Division—a Maybach

300-horsepower and a B. M. W. Both Avere considered excellent

examples of German design, and a complete test of their altitude

performance was desired.

Accurate knowledge as to the influence of compression ratio on

engine power and economy is of so great importance that every effort
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 101

has been made to make the investigation- of this subject as complete

as possible. This has necessitated tests covering a wide range of

engine speed, engine power, carburetor air temperature, jacket water

temjDerature, etc. The data thus accumulated not only give the desired information concerning the influence of compression ratio, but

also much supplementary information as to the effect on engine performance of changes in carburetor air temperature, jacket temperature, etc. During some of the above tests difficulty was experienced in the

engine operation, which was eventually traced to the formation of

snow in the manifold. This snow formation seemed a likely source

of engine failure in service and one that under service conditions

would be hard to detect. A technical note was therefore prepared

describing the trouble, explaining its cause, and suggesting its cure. Eleven reports covering investigations and tests carried out in the

altitude laboratory have been prepared, as noted under the heading

" Publications."

Ignition.

Ignition problems have been handled jointly by this and the Electrical Division of the Bureau, and a portion of the work is described

in the report of that division.

Tests have been made on a number of spark plugs and attachments

to be used with them at the request of the Motor Transport Corps

and also for other Government departments and for manufacturers.

Tests have also been made upon several special porcelains which

have been developed by various manufacturers for use as insulators

in spark plugs.

A study has been begun of the effect of the electrical character of

the spark upon its ability to ignite gasoline-air mixtures under ex- treme conditions of mixture ratio and dilutions which may occur in

automotive practice. Under such conditions there is some evidence

• that the character of the spark affects its igniting power, and sparks

can be produced which are visible to the eye but which do not produce ignition. Oscillograms have been taken of the current in the

spark under such conditions.

A report on The Mathematical Theory of Induced .Voltage in

High-Tension Magnetos has been prepared for publication by the

Bureau, and a second paper on Simplified Magneto Mathematics will

appear as a report of the National Advisory Committee for Aeronautics. A short paper on Causes of Cracking of Ignition Cables

has also been printed as a technical note of the National Advisory

Committee for Aeronautics.

Lubrication.

The general program of the lubrication laboratory is an investigation of the relations between the behavior of lubricating oils in

service and the accepted physical and chemical laboratory tests. For

this purpose an extended study has been made of a series of oils before and after long-continued service in a typical automobile engine.

Oils derived from paraffin and naphthene base crudes were compared

to determine, if possible, their relative merits for use as lubricants

in automotive engines. While the results of these extended tests
102 REPORT OF DIRECTOR 01' BUREAU OF STANDARDS.

show characteristic differences between the two classes of oils, no

si^ificant differences in lubricating value have been demonstrated.

Trogress has been made on the development of tests for the behavior of standard stock bearings under various conditions of service and of lubrication, also in the development of a test for the relative values of various oils in preventing seizure of bearings under

high unit pressures.

The laboratory has cooperated with the Army in the development

of a special oil for recoil mechanism of aircraft machine guns and

has undertaken the development of a special test for consistency of

aircraft engine oils at low temperatures. It has cooperated with the

Interdepartmental Committee on Standardization of Petroleum

Specifications in the preparation of specifications for Government

purchases. It has undertaken tests of special products for the

United States and some of the State governments and in a few cases for private companies.

An extensive series of efficiency tests of rear axles for trucks has

included a comparison of power losses Avitli oils and greases with and

without the addition of graphite. The results of these tests are as yet inconclusive as to the effect of graphite when used in this

manner.

Carburetion.

Two major problems have been under investigation, one of these

dealing with mixture control for aircraft engines at altitudes, the

other with the distribution of liquid and vaporized fuel in the intake

manifold.

As the air grows less dense with increasing altitude, the usual cor- buretor of an aircraft engine supplies a richer' and richer mixture

of fuel with air. For economical operation this tendency must be

corrected by some form of manual or automatic control. A carburetor

which will inherently maintain a correct fuel ratio at ail altitudes is almost an essential, particularly for military purposes. A general

study of the laws of flow in carburetion is in progress.

The second problem relates to the development of means for measuring and specifying the quality of an air-fuel mixture in the intake

manifold. The proper operation of all engines supplied with liquid

fuel by a carburetor depends upon the condition of the mixtu;re as it enters the cylinders. Means have been developed for measuring the

evaporation which takes place at any section of the manifold.

The characteristics of air flow and mixture ratio were determined

for each of two German aviation carburetors, the B. M. W. and the

Maybach, and detailed analyses of the operation of these carburetors

under various conditions of service were prepared.

As a portion of a study of the subject of the fuel economy of

various current automobile carburetors, tests were conducted on six

widely used types and the mixture ratio determined for changing

loads at different constant throttle openings and for changing throttle

positions at different constant speeds.

Phenomena of Combustion.

In order to understand more completely the combustion of fuels

in engine cylinders, experimental studies have been made of the rates

at which fuel-air mixtures burn under carefully controlled conditions.
REPORT or DIRECTOR OF BUREAU OE STANDARDS, 103

The effect of changes in the proportions of air and fuel have been determined with acetylene, and further work with carbon monoxide

and gasoline vapor under increased pressures and at high temperatures is contemplated. A new method of studying the combustion of

gases at constant pressure has been developed which gives promise

of great value.

Some preliminary experiments have been carried out in an engine

to determine the rate of passage of the flame through the gas mixture, using as an indicator the effect of the flame upon the breakdown

voltage of a spark gap. These showed, however, that the turbulent

motions of the gas were so great and so variable from one explosion

to the next as to mask any effects from the finite velocity of propagation.

A one-cylinder engine has been used in a study of combustion

phenomena. Particular attention has been given to an investigation

of the causes of fuel knock and to measurements of pressure that exist when fuel Imock is present. In addition to this work short tests

of spark plugs, ignition devices, and some fuel comparisons have

been made. Included in the latter was a series of runs with hydrogen as a fuel, made at the request of the Balloon and Airship Section

of the United States Army.

Cooling Problems.

The staff engaged on this Avork has completed a sj^stematic compilation and reA'ision of all the research work on aircraft radiators

covering the past several years and the preparation of a comprehensive report on the results of this Avork which will constitute a

treatise on the subject of aircraft and other cooling radiators. A

considerable amount of new experimental work has been required

for the verification of earlier results. In addition an extensive

development work of a confidential nature has been carvied on for

the Army.

Truck Rear Axles.

At the instance of the Motor Transport Division, Quartermaster

Corps of the Armj', the Bureau has carried out comparative tests on a number of rear axles suitable for Army trucks. This investigation has been onl_v partly completed and includes determination

d of the efficiency of .power transmission of each axle over the Avhole

range of speeds and power transmitted for which the axle is suited

and also endurance rims arranged to bring out any weaknesses that

may exist.

The purpose of this work is to aid the Motor Transport DiAasion

in determining the axles best suited to their requirements in connection Avith replacements and to obtain information which will be of

value in connection with new construction Avork. Another of the

objects of this investigation is to furnish manufacturers information

Avhich will be of direct benefit to them in their efforts to improA^e their

product. The endurance" tests, by bringing out what parts may be

relatively weak compared with the remainder of the structure, are proving particularly useful in this direction. The Bureau expects

upon completion of this investigation to be able to publish a considerable amount of data of general interest.
104 EEPORT OF DIRECTOR OF BUREAU OF STAlfDARDS.

Standard Method of Testing Brake Linings.

Manufacturers and large users of brake lining materials for automotive equipment have long realized the advantages which would

result from establishing a standard method for testing these

materials.

In the absence of such a method various simple tests were made

by some of the makers of linings to keep a check on their product

and to try out new types, while car builders specified certain methods

of testing the materials for use on their cars. As the conditions of

these tests varied widely, the results were usually not comparable.

At the instance of the Motor Transport Corps, the Bureau of

Standards has carried on an extended investigation to ascertain the

best conditions for a standard test for brake linings. A program

was prepared in cooperation with the Motor Transport Corps and

the Society of Automotive Engineers' Standards Committee some- what over a year ago. This provided for investigation of the coefficient of friction of linings ; the influence of water, oil, wear, and

temperature on this coefficient; tests for durability by means of

both long-time runs and severe service runs ; also for supplementary

tests dealing with tendency of hot linings to stick on drum while

cooling, and other features.

The Bureau's work was fully reported on and discussed at a con- ference held in May and at which representatives of the Motor

Transport Corps, the Society of Automotive Engineers, and a large

number of makers of linings and others were present. Tentative

recommendations for test equipment and methods of test were made

by the Bureau.

Further work was necessary before final conditions could be determined on, and this work is being carried out. Meanwhile a number of the makers are installing test apparatus in line with

the equipment used by the Bureau and will carry out tests on the

basis of the Bureau's tentatiA^e recommendations. The results and

additional experience thus obtained promise to aid in reaching more

definite conclusions.

Miscellaneous.

At the request of the Ordnance Department a test was made on a

roof engine to determine the performance of the engine as indicated

by the power developed and the weight of fuel consumed per horsepower-hour under full-load conditions when equipped with various

induction sj'stems and with heavj^ and light pistons and connecting

rods.

Tests were made on a number of special radiator cores for the

Engineering Division of the Air Service, McCook Field, as well

as i'or the Bureau of Steam Engineering of the Navy Department.

A clearance volume indicator and balanced diaphragm engine

speed indicator were furnished by this laboratory to the Engineering

Division of the Air Service, McCook FieM, for use in connection

with various engineering problems at that field.

Engine tests were carried out on a number of specially desigTied

spark plugs.

At the request of the Motor Transport Corps a number of special

fuel " dopes " and so-called gasoline intensifiers were analyzed and

subjected to engine tests.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS,- 105

TESTING, INFORMATION, AND PUBLICATIONS.

Thermometer, Pyrometer, and Heat Tests.

The tests completed in the division during the year are summarized

as follows

The number of liquid-in-glass thermometers of all kinds, exclusive

of clinical thermometers, submitted for test was 4,211, of which 2,144

were certified and 1,745 received reports, the failure to receive certificates being due either to defects in design or construction or to the

fact that the errors exceeded the established tolerances. Of the re- maining thermometers, 131 were broken either when received or

in test and 191 were rejected. Among those submitted Avere 489

calorimetric thermometers, 138 precision calorimetric thermometers,

166 Beckmann thermometers, and 94 clinical standards. Of the re- maining thermometers, 1,877 were classed as high-temperature thermometers, being listed at temperatures above 100° C. The increase

in the number of high-temperature thermometers submitted represents the most notable change in the character of the testing work.

"While the greater part of the high-temperature thermometers submitted were found to be suitably annealed, an u.ndue proportion, including several large lots, were rejected due to insufficient annealing.

It was found, hoAvever, that failure to anneal thermometers was due

to carelessness rather than ignorance on the part of the manufacturers. Details relating to testing of clinical thermometers have

already been given.

In addition to the above there were tested 29 resistance thermometers and 30 thermocouples, some of the latter being representative of

large amounts of wire to be used in fire tests. Fifteen freezing-point

tests and a number of special tests of an investigative character were

also made.

In the high-temperatux-e laboratories tests T\'ere made of 134 thermocouples, 17 indicating instruments for thermocouples. 12 optical

pyrometers, 8 lamps for optical pyrometers. Melting-point tests of

35 materials, such as metals, alloys, fire brick, sand, ash, etc., were

made. The number of standard melting-point samples distributed

was 287.

In the heat-measurements section two gas calorimeters and one

mechanically cooled refrigerator were tested, the latter at the request

of the Public Health Service. The number of standard combustion

samples distributed was 310.

A number of tests completed in the sections dealing with the fireresistive properties of structural materials and with automotive

power plants fuels and lubricants were not of a routine character

and have been summarized in the reports on those sections.

Information, Cooperation with Societies, Etc.

An important part of the division 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. Information relating to apparatus developed by the division, such as thermometer comparators

used in the thermometric laboratories, a precision pressure gauge,

resistance thermometers, a clearance volume meter, an engine indi-
106 REPORT OF DIRECTOR OP BUREAU OF STANDARDS.

cator, etc., has been supplied by means of blue prints and descriptive

matter in answer to numerous inquiries. Information which will

make it possible to improve the fuel economy of automobile engines

has been supplied to manufacturers.

Members of the division have cooperated in the activities of various

scientific and technical societies and organizations, including : The

American Chemical Society, the American Concrete Institute, the

American 'Society for Testing Materials, the American Society for

Steel Treating, the American Society of Heating and Ventilating

Engineers, the American Society of Mechanical Engineers, the American Society of Refrigerating Engineers, the American Physical Society, the Association of American Clinical. Thermometer Manufacturers, the Hollow Building Tile Association, the New Jersey Clay

Products Association, the Optical Society of America, the Society of

Automotive Engineers, the Western Society of Engineers, the General Supply Committee, the Associated Factory Mutual Fire In- surance Companies, and Underwriters' Laboratories (Inc.).

The division has been actively represented in the committee work

of several of these societies, notably the American Society of Refrigerating Engineers, the American Society for Testing Materials,

and the Society of Automotive Engineers. Numerous papers dealing

with the work of the division have been presented before scientific

and technical societies.

Publications.

The following publications relating to the work of the division

have appeared during the year among the publications of the Bureau

of Standards and may be obtained from the office of the Superintendent of Documents, Government Printing Office, Washington, D. C.

Prices are given in Bureau of Standards Circular 24

Recent modifications in the construction of platinum resistance thermometers

(T. S. Sligli, jr.), B. S. Sci. Papers, 17, p. 49; 1921 (No. 407).

A new microphotometer for photographic densities (W. F. Meggers and Paul

D. Foote), B. S. Sci. Papers, 16, p. 299; 1920 (No. 385).

Atomic theory and low-voltage arcs in Caesium vapor (Paul D. Foote and W. F. Meggers). B. S. Sci. Papers, 16, p. 309; 1920 (No. 386).

Ionization and resonance potentiaLs of some normietallic elements (F. 1j. iloliler and Paul D. Foote), B. S. Sci. Papers, 16, p. 669; 1920 (No. 400).

Resonance potentials and low-voltage arcs for metals of the second group of the

periodic table (F. L. Mohler, Paul D. Foote, and AY. F. Meggers). B. S. Sci. Papers, 16, p. 72.5; 1920; 1920 (No. 403).

Pyrometric practice (Paul D. Foote, G. 0. Fairchild, and T. R. Hai-rison), B. Tech. Paper No. 170 ; 1921. Fire tests of building columns (S. H. Ingberg, H. K. Griffin, W. C. Robinson,

and R. E. Wilson), B. S. Tech. Paper No. 184; 1921. The papers listed below have appeared in current scientific and

technical publications

Notes regarding the construction of platinum resistance thermometers and immersion heating coils of low lag (T. S. Sligh, jr.). Jour. Am. Chem. Soc, 43,

p. 470 ; 1921.

Note on partial and total immersion thermometers (C. W. Waidner and E. F. Mueller), .Jour. Indus, and Eng. Cheni., 13, p. 237; 1921.

Ionization and resonance potentials for electrons in vapors of lead and calcium

(Paul D. Foote, F. L. Mohler, and H. F. Stimsou), Phil. Mag.. 40, p. 73; 1920.

The ionization potential of hydrochloric acid and the electron affinity of chlorine

(Paul D. Foote and F. L. Mohler), Jour. Am. Chem. Soc, 42, p. 1832; 1920.

The therniochemi.stry of ionization of vapors of certain components (Paul D.

Foote and F. L. Mohler). .lour. Wash. Acad. Sci., 10, p. 43.5; 1920.
KEPORT or DIRECTOR OF BUREAU OF STANDARDS. 107

Kesontince potentials and low-voltage arcs for metals of the second group of the

periodic table (F. L. Mohler, Paul D. Foote, and W. F. Meggers), Jour. Opt.

Soc. of Am., 4, p. 864; 1920.

The absorption of heat in glass (A. Q. Tool and C. G. Eichlin), Jour. Opt. Soc. of Am., 4, p. 340 ; 1920.

Note on a new method of joining glass (C. O. Fairchild), Jour. Opt. Soc. of

Am., 4, p. 496 ; 1920.

Thermal conductivity of heat insulators (M. S. Van Dusen), Jour. Am. Soc. Heat, and Vent. Engs., 2'o, p. 82.5; 1920; also in Jour. Am. Soc. of lief. Engs.,

7, p. 202 ; 1920.

^Spwiflc volume of anhydrous li(iuid ammonia ( C!. S. CragDe and D. K. HariH-'r,

3d), .Jour. Am. Soc. of Ref. Engs., 7, p. 113; 1920.

Bureau of Standards report of progress in the determination of the fundamental

constants Of refrigeration engineering, published in Jour. Am. Soc. of Ref.

Engs., 7, p. 33S ; 1921.

I'ressure-relief diapliragms (H. F. Stimson), Jour. Am. Soc. of Ref. Engs., 7, p. 380 ; 1921. G)-avitation and relativity (C W. Kanolt), Jour. Franklin Inst., 190, p. 211;

1920.

. The relation between Ihe compression rat.o and the tiiermal ef'.iciency of an

airplane engine (S. W. Sparrovv^, Jour, of the Soc. of Automotive Engs.

Intake manifold temperatures and fuel economy (W. S. James, H. C. Dickinson,

and S. W. Sparrow), Jour, of the Soc. of Automotive Bugs., August, 1920.

Possible fuel savings in automotive engines (H. C. Dickinson and S. W. Sparrow), Jour, of the Soc. of Automotive Engs., January, 1921.

Automotive research with reference to fuels and lubricants, Bureau of Standards, Department of Commerce (D. R. Harper and H. C. Dickinson), Petro- leum Magazine.

iKlements of fuel economy (W. S. James), Jour, of the Soc. of Automotive Engs.,

June, 1921.

REPORTS OF THE NATION .4L ADVISORY COMMITTEE FOE AERONAUTICS.

Performance of a Liberty 12 airplane engine (S. W. Sparrow).

Performance of a 300-horsepower Hispano-Suiza airplane engine (S. W. Spar- row )

Some factors of airplane engine performance (V. R. Gage).

A high-speed engine-pi-essure indicator of the balanced diaphragm type (H. C. Dickinson and F. B. Newell).

Turbulence in the air tubes of radiators for aircraft engines (S. R. Parsons).

TECHNICAL NOTES OF THE NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS.

An instrument for measuring engine clearance volumes (S. W. Sparrow).

A variable-speed fan dynamometer (Karl D. Wood).

High thermal efficiency in airplane service (S. W. Sparrow).

Increase in maximum pressures produced by preignition in internal-combustion

engines (S. W. Sparrow).

Causes of cracking of ignition cables (F. B. Silsbee and J. B. Dempsey).

Plane crashes: Engine trouble. A possible explanation (S. W. Sparrow).

The following papers are in press or have been submitted for

publication

Testing of thermometers. B. S. Cir. No. 8, 3d ed. Soft X rays from arcs in vapors (Mohler and B'oote), Jour. Apt. Soc. of Am.

The excitation of the enhanced spectrum of magneslmn in a low-voltage arc

(Foote, Meggers, and Mohler), Phys. Rev.

Characteristic X rays from arcs in gases and vapors (Mohler and Foote), .Tour. Wash. Acad. Sci. Total heat diagrams for Ammonia (Mueller and Meyers), Jour. Am. Soc. Ref.

Engs.

The specific volume of liquid ammonia (Ci'agoe and Harper), B. S. Sci. Paper.

The production of liquid air on a laboratory scale (Cook). B. S. Sci. Paper.

I'rovision in concrete construction against extreme fire conditions (Hull),

Proc. Am. Concrete Inst. Radiators for aircraft engines (I'arsons and Harper), B. S. Tech. Paper.

TTni
108 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

The Mathematical theory of induced voltage in high-tension magnetos (Silsbee), B. S. Tech. Paper.

Performance of Maybach 300-horsepower airplane engine (Sparrow), Repts.

Nat. Advisory Com. for Aeronautics.

Performance of B. M. W. 185-horsepower airplane engine (Sparrow), Repts. Nat. Advisory Comm. for Aeronautics.

Simplified magneto mathematics (Silsbee), Reps. Nat. Advisory Comm. for

Aeronautics.

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 especially applicaable,

and the development of infra-red photography; for astronomical observations and aviation purposes; polarimetry, devoted to investigations and tests involving measurements of polarized light and its application, especially in the testing, standardization, and tech- nology 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 porperties of materials, and the color grading of light sources and materials; refractometry and optical instruments, interested

chiefly in the performance and development of optical instruments and materials, includ- ing refractive indices and disperson measurements; radiometry, which covers the rtore . 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; inter- ferometry, which makes use of the light wave as a standard unit for high-precision

length measurements and develops the application of interference methods; and photographic technology, concerned with the investigation of photographic apparatus, testing

of photographic materials and devices, standardization of testing methods, and general

photographic investigations. It includes, also, the optical investigation and measuring

of the physical properties of dispersoids, such as smoke, water supplies, etc., and inves- tigations in cooperation with the Engineer Corps of the Army on the conditions governing searchlight illumination, with special reference to the testing and improving of searchlight mirrors and search-lamp performance.

SPECTROSCOPY.

Standard Wave Lengths.

The high precision with which the lengths of certain waves of

light can be measured or compared is now more or less of a commonplace, but the importance of such measurements is ever increasing. Extensive use of standard wave lengths of light for

testing the lengths of gauges, for ruling scales, and testing the con- stancy of such material standards are practical applications of comparatively recent origin, and the increased accuracy of all spectroscopic data based upon the international standards now makes it possible to calculate some important physical constants and to realize

the significance of spectral series in connection Avith atomic models

and radiation theory.

Since the international adoption in 1906 of the wave length

(6,438.4696A) of the red radiation from cadmium as the primary

standard of wave length, a considerable number of other radiations

have had their wave lengths compared by interferometer methods

with the primary standard, and some of these were adopted as international secondary standards. The history and present status

of this subject was summarized during the past year in a RejDort on

Standard Wave Lengths, published in the Journal of the Optical

Society of America, July, 1921.

The spectra of the inert gases—helium, neon, argon, krypton, and * xenon—contain radiations which are remarkably homogeneous and '

reproducible. The precision with which such radiations can be < defined makes them valuable as wave-length standards and has

theoretical importance in analyzing the structure of the spectra.

In Bureau of Standards Scientific Paper No. 329 the values of 54 If;
KEPOET OF DIRECTOR OF BUREAU OF STANDARDS. 109

wave lengths in the spectrum of neon were given, and attention was

called to the constancy of frequency differences among certain

groups of lines. During the past jeav similar measurements were

made on the wave lengths of 50 lines in the argon spectrum, 18 in

krypton, and 12 in xenon. The values are considered to be correct

in most cases to one part in several millions, and frequency differ- ences recurring among lines in the spectra of argon and krypton

were found to be constant within the limits of probable error in

these wave-length measurements. The exactness of the combination

principle of Ritz has thus been verified for the three elements

argon, krypton, and xenon. In addition to these measurements of wave lengths in the spectra

of gases the interferometer has been employed in further determinations of standard wave lengths in the arc spectrum of iron. The

longer waves in the red and infra-red spectral regions are being

compared with the primary standard, and it is planned to continue

this work during the coming year.

Investigation of Arc Spectra.

Five years ago this laboratory began a program of wave-length

measurements in arc spectra of the chemical elements. The object

of this investigation was to describe as accurately and as completely

as possible the characteristic spectra of all the chemical elements,

especially in the red and infra-red spectral regions to which ordinary

photographic materials are insensitive. With the aid of photographic })lates stained with photosensitizing dyes the Bureau has

succeeded thus far in determining standard spectra for more than

half of all the known chemical elements. During the past year the

! results were published (Bureau of Standards Scientific Paper No.

i 411) for arc spectra photographed in the yellow, red, and infrared for the following elements : Silver, gold, lead, mercury, tin, zinc,

antimony, and bismuth.

In many respects the group of rare earth elements is the most interesting of all the chemical elements in the periodic system. This

group contains 16 elements, with atomic numbers from 57 to 72, both

inclusive, but No. 61 is still unknown. The absorption spectra of

these elements in solution are marked by strong bands which are relatively narrow and unlike those of most of the other elements, while

j their emission spectra are extremely rich in fine lines of moderate

j intensity. Samples of most of the rare earths have been collected

from various sources for purposes of spectral analysis and other data,

the most extensive collection being that prepared in Austria by Carl

Auer von Welsbach for Prof. J. M. Eder's spectroscopic investigations. Excellent samples of some of the elements were presented to

this laborator}^ by Prof. B. S. Plopkins, of the University of Illinois,

and by Prof. James, of Durham College. The first of a series of

Bureau of Standards' Scientific Papers on these materials was prepared with the cooperation of the University of Illinois and is now in

; press. It describes the chemical separation and purification of eight

'! elements and contains about 2,500 wave-length values in the yellow,

I red, and infra-red arc spectra of yttrium, lanthanum, and cerium.

I In addition to these results the arc spectra of neodymium, samarium,

gadolinium, dysprosium, zirconium, columbium, europium, erbium,

I
110 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

holmium, and didymium have been carefully investigated and many

thousands of wave leno'ths have been measured in the arc spectra of

these elements.

Similar work has been begun on the arc spectra of ruthenium,,

rliodium, palladium, osmium, iridium, and platinum, very pure sam-

])les of which have been prepared by the Chemistrj/ Division of this

Bureau. It is hoped that the longer wave spectral regions for these

- so-called platinum metals as well as for the rare earths and similar

elements may be completely defined within another year.

Spectroscopic Analysis.

This laboratory has been called upon during the past year to

make spectroscopic analyses of more than 130 miscellaneous materials, including tool steels, rare earths, platinum metals, mint gold,

thermocouple materials, storage battery materials, colored glasses,,

enamel, various alloys, etc. In the preparation of metals in a very

high state of purity the spectroscope gives valuable assistance in

detecting traces of impurities and in controlling the chemical procedure for further purification. The spectral method is in many

cases more sensitive and convenient than the chemical method for

detecting impuiities, and for this reason it is highly desirable to

study the partial spectra of elements present in mixtures, alloys, etc.,

to establish a quantitative basis for spectral analysis. The induction

furnace has made it easy to prepare standard alloys of metals in

definite proportions, and spectral examination of these shows that

it is possible to make precise quantitative analyses within certain

limits. The Metallurgy Division of this Bureau has prepared such

{Standard alloys of iridium with platinum and of iron, copper, lead,

and silver with gold. These impurities in the range from 1 per cent

to 0.0001 per cent can be determined with dispatch and precision from

an examination of the spark spectrum. It is possible for the United

States Mint to adopt this method of analysis of proof gold for which

the chemical and fire-assay methods are both more tedious and uncertain.

Spectrum Tubes.

Electrical discharge tubes containing pure gases are used extensively for purposes of optical testing, research, and instruction. Such

tubes have been difficult to obtain in this country, and the spectroscopy section of this Bureau has been unable to supply the large demand for them. About 100 tubes containing either hydrogen, oxygen, nitrogen, helium, neon, or argon were made during the past

year and furnished to research and testing laboratories, astronomical observatories, colleges, and universities.

In cooperation with a section of the Heat Division which has

investigated electrical phenomena of radiation from low voltage

arcs spectral analyses were made of the radiation from such sources. The single-line spectrum from magnesium vapor was photographed

(Scientific Paper No. 403), and more recently the conditions neces- sary for the production of the two-line spectrum, the arc spectrum,

and the spark spectrum of magnesium were determined from spectroscopic observations (in press). Similar work is in progress with

other metals, various spectra of cadmium, sodium, and potassium
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. Ill

having been photographed thus far. This investigation gives important information on atomic structure and on the mechanism of

radiation.

Photosensitizing and Hypersensitizing.

The great need for specially sensitive photographic plates for

spectroscopic investigations led to experiments in photosensitizing

and hj'persensitizing which have resulted in photographic materials

far superior to any obtainable on the market. The chief object has

been to increase the sensitiveness of photographic emulsions to red

and infra-red light. The success with which such emulsions have

been prepared and applied to spectroscopic investigations, to longrange ground photography and aerial photography for haze penetration, and the possibility of using red sensitive emulsions for daylight photography of stars, all these are factoids which urged the

continuation of exj^eriments to develop certain characteristics of

photographic materials.

During the past year, accordingly, further studies have been made

in (1) color sensitizing ordinary emulsions by bathing in solutions

of photosensitizing dyes, and (2) hypersensitizing commercial panchromatic emulsions with ammonia or water. In cooperation with

the photographic laboratory quantitative measurements of the

speeds, filter factors, etc., have been made with these specially

treated emulsions and some interesting and important information

obtained on the relative values of different methods of treatment as regards spectral sensitivity, total speed, keeping qualties, fog, etc. These results Avill appear in a Bureau of Standards Scientific Paper.

POLARIMETRY.

Polarimetric Work,

In the previous report tliere was stated the fields of endeavor in

which the greatest demands were being made upon the Bureau for

assistance and the necessity for meeting these demands as far as available funds and equipment would permit. Attention was directed to the increasing demand for the standardization of methods

of anal^^sis, the standardization of technological processes, and for

accurate data on the fundamental constants of the sugars and their

associated products. The results which have been attained in meeting these demands have been gratif3dng. By rearrangement of space

already utilized for other work suitable temporary? quarters have

been found and apparatus and equipment installed to permit of investigational and standardization Avork in the new fields. As a re- sult the Bureau now has new laboratories, fairly well equipped, devoted to the rare sugars, their production, and the determination

of their physical and chemical propeities ; molasses and simps, and

sugar testing ; the study and standardization of quartz control plates

the measurement and study of double refraction; the standardization of saccharimeters ; the standardization of decolorizing agents,

including vegetable carbons and inert materials.

In addition to the above two complete plants for the study of

the standardization of technological processes in sugar manufacture

are in process of installation. The larger of these will permit of ex- perimental work with quantities of raw material weighing several
112 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

hundred pounds. The smaller is an exceedingly flexible plant, involving every step utilized in modern sugar factories, but carried out

on a laboratory scale so as to make possible preliminary work with

only a few pounds of raw material. The results obtained through

the utilization of the small laboratory plant can be verified on a near

factory scale by the use of the larger plant. It is apparent that the

derived results will by this means be thoroughly tried out and verified

before application is attempted in the large sugar factories throughout the country. Experimentation in the factories is always difficult

and expensive and interferes with the conduct of the business of the

particular factory which is being utilized. It is thus obvious that

the Bureau will make every effort to establish the complete success of the standardization of a process before it is even experimented

upon in actual factory operations. The work of designing and suc- cessfully building the large number of units for these experimental

plants is obviously difficult and slow. Sufficient progress, however,

has been made to enable a partial, if not full, utilization of these

plants during the current year.

Standardization of Sugar Manufacture.

The present period of readjustment is a trying one for the sugar

industry. The economic need of research and specifications for the

standardization of methods of manufacture of sugar is being felt

more keenly than ever, especially by that portion of the industry

which, for various reasons, has never had recourse to any wellplanned research and other study of its problems. In spite of increased need for such service the research departments of the larger

manufacturers will almost inevitably be affected by the general spirit

of retrenchment which must accompany the readjustment. With

these facts in view the Bureau has outlined and begun research along

certain lines which should prove of general assistance.

The Rare Sugars.

The sugar group includes a large number of substances which

are very widely distributed in nature and which, from many points

of view, are becoming more and more important. While many

members of the group occur free in various plant and animal products, others are constituents of more complex compounds, and some,

so far as is known, do not exist naturally. These latter compounds

are only obtained by synthetic methods in the laboratory.

At the present time the most important use for these substances

is in pathology. By means of certain sugars or their derivatives,

such as the corresponding alcohols, certain pathogenic organisms

may be identified or closely related species may be differentiated.

For this purpose the compounds must be of the highest attainable

degree of purity.

Their preparation in this condition is often associated with considerable difficulty, and therefore requires the skill of an expert. It

is for this reason, and also the fact that the work is only in the

pioneer stages, often lacking the most fundamental data, that the

market prices are extremely high, ranging from $10 to $500 per

pound. This naturally restricts their use. It is, nevertheless, noteworthy that whereas up to the time of our entry into the war all
EEPOET OF DIEECTOK OF BUEEAU OF STANDAEDS. 113

/ substances were obtained from Germany, now American manufacturers are producing a number of these sugars and sugar derivatives in a state of purity and at a price comparable with those existing before the war. However, there is vast room for improvement,

not only in respect to their purity and availability at greatly reduced

prices, but also in the production of a large number of these substances that are as yet unavailable and which could undoubtedly be

of great assistance to and simplify the work of the pathologist.

While the above-mentioned application of the rare sugars at the

present time is perhaps the most important, other factors regarding

them are nevertheless to be considered. It is only by means of a

systematic study of the whole group that any degree of progress can

be made in the individual cases. In order to assist the industries immediately interested in this

group of compounds and to assist the medical profession by making

the sugars more available at a much reduced price and in a higher

state of purity and to contribute to the knowledge of the sugar group

itself, a section has been developed for the study of the rare sugars.

The work has already met with considerable success. The first half of the year was devoted to equipping a laboratory,

obtaining the necessary apparatus, and getting it into operation.

The remainder of the year was spent in making various compounds

to be used as starting material for various problems that are in progress. These problems are especially directed toAvard obtaining the

sugars in the highest possible state of purity and the determination

of their physical constants, especially their specific rotation, with

the utmost degree of accuracy. This will enable all workers to have

a standard of purity by which to judge their results. The meager

data which are now in existence on this subject are Avholly inadequate

to meet the demands for even commercial manufacturing operations.

As a concrete result of the Bureau's efforts in this field convenient

and economical methods have already been perfected for preparing

three of the rare sugars, namely, raffinose, galactose, and mannite.

Polarimetry of Oils.

Many oils, whether of the mineral, fatty, or essential classes, are naturally active ; that is, they rotate plane polarized light to a greater or less degree, and all become active or doubly refracting in varying

degrees when j)laced in a magnetic or electric field. Measurements

on these properties make it possible to identify oils, to detect adulteration, and in many cases to determine their composition and molecular structure. Data of this sort obtained on oils used in foods,

drugs, fuels, paints, etc., have great commercial value. During the

year progress has been made in collecting such data and in devising

better methods of making the required tests, especially in regard to

the measurements on the electric double refraction.

Quartz Control Plates.

A plate of crystalline quartz, cut perpendicular to the crystallographic or optic axis, has the power of rotating the plane of polarization of a beam of plane polarized light in the same manner as a sugar solution. Advantage has been taken of this fortunate circumstance to provide a positive and unchangeable device in the form of

64984—21 8
114 REPORT OF DIRECTOR OE BUREAU OF STANDARDS.

the quartz control plate for checking the accuracy of saccharimeters.

The saccharimeter, being a very complicated and delicate piece of

apparatus, may easity get out of adjustment, thereby rendering uncertain the test of a sugar. Every inaccuracy due to this condition is

wholh' avoided by placing a control plate in the instrument and comparing the reading obtained with the standard value of the plate.

These plates are thus of fundamental importance throughout the

sugar industry and in scientific laboratories as well. During the

year 142 of these plates were tested, 131 of which were Americanmade plates. Twelve were rejected as being unfit for precise saccharimetric work, either because of inhomogeneity of the quartz or because of improper mounting.

With the idea of being of the greatest possible assistance to tlie

sugar industry, the Bureau has continued its policy of remounting

and testing improperly mounted plates when they are already in the

possession of the industry, but rejects them when they are submitted for test by the makers. This serves to make reliable many

plates which would otherwise be unfit for accurate work and in a measure to prevent unfit plates from reaching the industry. On

account of the fact that a number of firms here and abroad have

undertaken the manufacture of quartz control plates, it has become

more than ever necessary that all such plates' be critically examined

' for defects. To aid in accomplishing this, the apparatus previously

utilized for testing the degree of planeness and parallelism of the

plate and the so-called " axis error " has been improved. These tests,

together with a critical examination of the mounting of the plate, are made in addition to the usual tests of homogeneity and sensitiveness

in the polariscope and the precise determination of the sugar value

of the plate.

The Bureau has been of considerable assistance to manufacturers

of quartz control plates and through them to the sugar industry as a whole by testing their plates, poin^ting out defects, and indicating

what points should be given more attention. A marked improvement

in the quality of the plates has resulted. First-class quartz control

plates of American manufacture are now available.

" Reaction " of Sugar Products.

By " reaction " is meant the degree of acidity or alkalinity of a product. In the previous year, by means of a recently developed

series of indicators, the reactions of a large number of granulated

sugars of commerce were determined. The experience acquired in

this work has been utilized in other applications, with the result that

the control of acidity and alkalinity appears to have a far more ex- tended application than was at first supposed. The colors of impure

products and the decolorization by means of charcoal is apparently

strongly influenced by the reaction of the solution. It has recently

develojDed that the flavor of a sugar siru]) is much improved by bringing it closely to a neutral reaction as shown by these indicators. In

some instances flocculation of contaminating colloidal impurities is

aided by adjusting to a proper reaction. The applications appear so extensive that further investigation by indicators and by electrical

methods has been planned.
KEPOET OF DIRECTOR OF BUREAU OF STANDARDS. 115

ioo° Point of the Saccharimeter Scale.

Owing to the abnormal world-wide conditions now existing in the

sugar industry, the basis of standardization of the saccharimeter

has taken on an added significance, and the necessity for international

agreement as to the value of the 100° point is greater than ever. The

Bureau has made continuous efforts looking to a solution of this diffi- culty. These efforts have finally culminated in some prospects for

success. The proper authorities in Germany have entered into negotiations with the Bureau regarding this matter, and a 100° sugar

quartz control plate has been forwarded to the Imperial Sugar Institute in Berlin. In the meantime the Bureau's correct value foi- the

100° point has become nearly universally adopted throughout Xorth

America. The new and largely increased tariff on sugar now in eifect

has doubled the importance of the Bureau's discovery of an error of over one-tenth of 1 per cent in the old value of the 100° point.

The saving to the Government resulting from this work now approximates $150,000 per annum.

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. Heavy importations of sugar have

necessarily created much additional work for the Bureau. It was

found that the facilities were inadequate for this work and the car- rying on of the control analysis of raw sugars. Additional sx^ace

was obtained and the new laboratory equipped to expedite this work.

During the year 1,570 exchange samples of raw sugar 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.

Grading of Commercial Sugars.

Laboratory work on the investigation looking to the preparation of

standard definitions and specifications for direct consumption sugars

has been practically completed. Grave difficulty has been experienced

in making practical application of the facts derived from these data.

A careful study of the manufacturing conditions under which many

of the sugars are used has been found necessary, and the preparation

of definitions requires a comprehensive study of the average practice

throughout the country in the utilization of refined sugars. The

necessary information must be obtained from many individuals who

have hacl years of practical experience in the manufacture and grading of these products.

Color of Sugar and Sirups.

The investigation of this subject is now well under way. It is connected very closely with the problem of standardizing decolorizing agents, which has been discussed under that heading. In the

problem of determining the color of sugar products the Bureau has

been greatlj' aided by the active cooperation of a number of the

large refineries. They have painstakingly prepared and forwarded

a great number of representative refinery liquors, and the work is
116 REPORT or DIRECTOR OF BUREAU OE STANDARDS.

being extended to cover all g-rades of liquors produced in factories as well as refineries. The technical colorimeters commonly in use have proven Avholly inadequate to meet the needs of the AA^rk, and

far more sensitiA-e and accurate methods, Avhich are available only

in an institution such as the Bureau of Standards, haA'e been utilized.

It Avas found that a less accurate procedure Avould not giA^e the

necessary facts, oAving to the necessity for determining the absorption of these liquors for the different Avave lengths of light. Excellent progress has been made in measuring these absorptions for all

classes of sugar products, ranging from molasses to the almost colorless grades of granulated sugars. When the Avork is completed, it will be possible to clearly define the outstanding characteristic color

phenomena of each class. It is expected that this, in turn, will lead

to an adaptation of the facts to the small, simpler needs of a large

variety of manufacturers. The Avork of standardization of colorimetric practice for the sugar industry, therefore, concerns itself not

only with tlie mode of analytical preparation of sugar products —

factor of far greater influence than heretofore thought possible

but also with the manner of calculating the results to a common unit

basis, employing different makes of commercial colorimeters. The

results thus far obtained indicate that it will be possible to create

a solid scientific basis for colorimetric practice, thereby making

possible a more scientific colorimetric practice in the industry, using

technical commercial instruments.

Preparation of Levulose.

Levnlose is the sweetest member of the sugar group and is wholesome for human consumption. It is A^ery widely and abundantly

distributed in plants that are capable of extensiA^e agricultural develo^jment. It occurs, for example, in the form of a starch called

inulin " in the roots of the dahlia and the Jerusalem artichoke, both

of Avhich may be grown extensively. Owing to the peculiar properties of the sugar—its great tendency to suffer decomposition and its

extremely high solubility-—its extraction" affords a problem of such

difficulty that pure levulose is one of the most costly sugars.

In the j)reAdous year experiments were made on the extraction from

invert sugar. During the past year the extraction of inulin from

plants and its conversion to leA'ulose has been studied. These experiments have shown that levulose may be prepared at a considerably

reduced cost, and that the material should readily become available

for scientific and bacteriological work.

Clerget Analysis for Sucrose.

In a paper entitled "The Double Polarization Method for Estimation of Sucrose" the Bureau made jDublic a series of modified

Clerget methods for the analysis of sucrose in mixtures, which make

possible an exact analysis in the presence of disturbing impurities.

These methods liaA-e already found application in the sugar industry.

Certain criticisms haA-e, howeA^er, appeared in the current literature. If valid, they Avould haA^e lessened the high degree of precision originally claimed for the methods. These criticisms led to an

extensive and minute examination of the fundamental principles

upon which the method Avere based. In every instance the basic

principles Avere found to be sound. This conclusion Avas reached not
REPORT OF DIRECTOR OF BUREAU OF STA^^DARDS. 117

only from the Bureau's experiments, but was also established from

outside independent experimental data. The discussion has furnished an important contribution toward placing the Clerget procedure among the exact methods of analysis.

Raffinose in Beet-Sugar Products.

Eaffinose, a sugar, occurs as an impurity in beet-sugar products.

Its analj^sis is therefore a question of great importance. In the pres- ence of sucrose it may be determined with sufficient accuracy by means

of the usual Clerget method. The latter, however, is strictly applicable only in the absence of other optically active impurities. The

products of the beet-sugar house contain unknown optically active

substances which vitiate the accuracy of the method. As the method,

is now used, all these substances are grouped together and are designated " raffinose." Not only is the estimation of true raffinose incorrect, but certain errors are introduced in the analysis of sucrose. This problem, in spite of extensive investigation, has proved a very

baffling question. A research is now being carried out by the Bureau

to find some selected property by which true raffinose may be determined. While the results obtained thus far are not wholly negative,

much further study will be required to obtain a satisfactory solution

of the problem.

In addition to the search for a distinguishing property of raffinose

in mixtures the preparation and optical rotation of the pure substance in solution have been studied in a preliminary manner.

Testing of Molasses.

The Bureau continued to act as referee between buyers and sellers

in the polariscopic analysis of molasses. Since a large proportion of

the molasses for manufacturing purposes is bought on the basis of

total sugar content and density, a number of manufacturers specify

that settlement be made on the Bureau's analysis. During the year

45 samples were analyzed. The Bureau's value of the Clerget divisor

has been adopted as a standard in the estimation of sucrose. A study

of a number of new methods of determining the amounts of reducing

sugars present in molasses is being made with the view of increasing

the precision of this determination. The investigation of the methods

of determining density has been continued, and the results are now

being tabulated. A modified form of picnometer for density determinations in this work has been designed and is being used in referee

testing of molasses and sirups.

The Bureau was requested by an association of cracker manufacturers to cooperate with them in an effort to establish specifications

for molasses. In this connection 10 representative samples of molasses were submitted by this association for test and a large volimie

of analytical data was obtained. As a result of the investigations of

both the association and the Bureau the former has issued a comprehensive bulletin on the subject to its members. From the results obtained in the research to secure a stable sirup of maximum density

it was possible to predict from the composition of a molasses whether

sugar would eventually crystallize out. From the same investigation, a method of preparing a sirup of stable composition was developed^
118 EEPOBT OF DIRECTOR OF BUREAU OF STANDARDS.

Beverage Sirups.

Assistance along lines similar to that discussed under the subject

of the testing of molasses was given manufacturers of beverages.

Wide diversity of procedure in the production of these sirups was

found, and practically all producers experience difficulty in preparing a satisfactory sirup. A number of sirups were made according

to practical formulae and analyzed. The indications now are that

methods devised by this Bureau will produce a sirup whose composition and properties will make it more suitable for beverage purposes.

The entire subject of specifications for molasses and sirups is still

under investigation.

Molasses Formation.

Owing to lack of facilities much of the specific work needed on

this problem could not be carried out. Most of the apparatus

necessary has been acquired and nearly erected. It is hoped that the

much-needed definite results will soon be obtained. A considerable

amount of valuable preliminary experimental work has been

carried out.

Decolorizing Agents.

For several years communications have been received at frequent

intervals from various industries requesting information on the

decolorizing power of various carbons, bone black, and other decolorizing agents. The use of these materials has greatlj' increased

in the last decade until they haA e become an indispensable part of

the manufacturing processes in many industries. This growth has

Qome about despite the fact that there has been no adequate method

of standardization or system by which their performance for a particular purpose could be gauged. The need for a method of

standardizing and grading the decolorization agents has been

noticeable in the sugar industry. An extended investigation and

study of the subject has therefore been undertaken with particular

reference to the requirements of the industry in order to secure the

necessary data for defining a method of standardization with re- gard to performance for all uses for which decolorizing agents are

applicable.

A large number of decolorizing agents have accordingly been collected with the object of studying their application to the problem of

decolorization of impure sugar liquors. The materials so far used

are samples of imported sugar as well as those produced by domestic

refineries.

The analj^tical preparation of these sugars necessarily includes a study of the effect by the so-called affination process. This process

aims at a preliminary refining of the raw-sugar crystals by mingling

them with concentrated sugar sirup, which is then swung off in

the centrifugal, removing thereby the greatest part of the coloring

substances with the machine sirups. The sugar crystals remaining

in the centrifugal basket are the so-called affined sugar, containing

now only a small amount of coloring matter. Decolorization is therefore being studied on liquors which are produced in the laboratory by close imitation of actual factory methods and practice.

The degree of decolorization is being ascertained by precision

methods, using an optical instrument known as a spectro-photom-
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 119

eter. The sensitiveness of this instrument has revealed the urgent

necessity of standardizing and placing upon a solid scientific basis

the analj'tical preparation of impure sugar liquors for colorimetric

analysis.

How urgent the standardization of this analyticaal preparation

of the liquors for colorimetric analysis really is will be appreciated

from the discovery that all filter aids—i. e., inert material, such as

filter-cel, kieselguhr, talcum, magnesium, carbonate, etc.—exercise a selective absorption, while all filter-paper filtrates are unsatisfactory on account of variation in pore size and the presence of

loose fibers. A further discovery has been made that the highest

grade long-fibered asbestos used as a filtering medium will deliver

an acceptable quality of filtrate.

A comparative study of the method of analysis described above

with other methods of preparation is now under way. It has been

found necessary to study the various methods of ultra filtration, the

object of which is to produce a so-called optical void or absolutely

clear liquid. No way could be found to obviate this extensive work,

as it is necessary to define the limits of accuracy of the unsatisfactory methods which have long been used in the technical colorimetry

of sugar products which wei'e develoj)ed without the present-day

knowledge of colloidal chemistry. The entry of decolorizing car- bons into industrial sugar manufacturing has developed the fact that

there is in existence at present no laboratory technique which can

cope with the manifold difficulties which develop when sugar solutions are exposed to the decolorizing action of carbons or which

are inherent in the nature of viscous impure solution.

In view of these facts which this important investigation has so far brought out, it is obvious why great difficulty has been experienced in industrial processes in the proper use of decolorizing agents,

and in view of the difficulties of developing a proper laboratory

technique it is no longer surprising that so little progress has been

made in solving this problem. The results so far obtained in this

work lead to the expectation that a satisfactory solution of the problem of standardizing and grading decolorizing agents will be at- tained.

The Laboratories for Sugar Technology.

During^ the year these laboratories have acquired more adequate

quarters, consisting of three large rooms, with the temporary use

of a fourth. Two of these rooms are equipped as laboratories for

the chemical and physical measurements and the clerical work and

supervision involved. The third is nearl}^ equipped as a pilot laboratory, the various parts or stations of which are ver^^ flexibly co- ordinated, so that the plant is readily adaptable to many different

problems. It is capable of being quickly converted from one type

of work to another, both as to kind of operations and as to their

sequence. For the fourth laboratory a plant of semicommercial

size has been designed. The apparatus so far obtained consists

mainly of what the sugar engineer terms " sugar-end " equipment,

in some cases single units of full-sized apparatus and in other cases apparatus of semicommercial size, specially designed for precise

work.

"1=771
120 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Several manufacturers liaA'e very kindly loaned part of the apparatus for the pilot laboratory and offered assistance of various kinds

in equipping the semicommercial plant.

Special Apparatus and Construction.

In order to carry on with the requisite precision the work on several of the problems in sugar manufacture it has been found neces- sary to employ neAV apparatus specially designed for the purpose.

Some of these designs have originated outside the Bureau, but a large proportion of them have been made here, occupying a considerable part of the time of the laboratories of sugar technology.

Whether originating outside or in the Bureau, however, nearly all

of these designs are the work of the present Bureau staff.

Gradation of Sugars by Sieve Analysis.

The importance of this undertaking was discussed briefly in last

year's report. The preliminary work is complete, and it is hoped

that a representative committee may be formed during the coming

year to pass upon specifications which will be proposed.

DifTusion Process in Sugar Manufacture.

It was found impossible to continue active work on the diffusion

process, important as it is, especially to the beet-sugar industry. The

year's work, however, indicates that the process has a broad field of

application, and a special battery has been sketched for use in the

rare sugar and related inchistries.

Storage and Shipment of Sugar.

The problems naturally falling under this heading are of great

economic importance to every interest involved, and yet apjDarently

it has not been the subject of much well-planned research. Most of

what has been established relates especially to raw sugar. The

caking of white, dry granulated sugar during storage and shipment

has been studied more or less extensively and with varying degrees

of success by several of the leading producers, but there is still a considerable question as to the best system of handling under the

various conditions commercially encountered. The Bureau has

studied and recalculated data obtained by one of these producers in

its laboratories and warehouses. This work is preliminary to a complete study with more refined technique, which the Bureau is undertaking.

Production of Mannite.

Owing to the Bureau's previous development of a method of producing d-mannite of high purity in considerable quantities for the

War Department, it has been possible to take up the important scientific problem of determining the physical constants of this rare

sugar. A quantit}' of the material has been purified in the laboratory to a very high degree and a number of measurements on the

specific I'otation made. Experience has shown that the Bureau can perform no greater service in this field than to leave a permanent rec- ord in the form of the exact values of the physical constants, of rare/

substances. Such data are not now in existence.
EEPOET OF DIRECTOR OE BUREAU OF STANDARDS. 121

Crystallization.

The general problem of crystallization has come to be an important

one in many industrial fields of endeavor. Its largest application is found throughout the sugar industry where a process of fractional

crystallization is utilized. The problems to be solved are largely

of the same nature, regardless of the commodity produced, whether

they be high-grade claemicals or new materials developed in the

Bureau's investigational work. The field is so broad that only an

entering wedge has thus far been made in the Bureau's investigation.

Delicate conti'ol apj)aratus has been designed and placed in operation

for the growing of crystals, and for the study of fractional crystallization special apparatus has been designed and erected.

Composition of Sirups of High Density.

The investigation of the composition and preparation of sirups of

high sugar content, of which a preliminary report was made the previous year, has been brought to completion. A considerable portion

of the sugar produced in this country is utilized in the form of

sirups. The necessity for specific information as to the best method

of preparation of these sirups for definite purposes has long been

recognized, and the problem of producing them in a stable form has

been a fundamental one in the sugar industry.

A saturated solution of pure cane sugar contains but G8 per cent of

sugar. Such a solution is too dilute for a useful commodity. If,

however, the sugar is partially inverted, thereby forming the mixture

of dextrose and levulose, Imown as " invert sugar," the content in

total sugars may be considerably increased Avithout resulting in a crystallization or " sugaring out." The investigation has disclosed

that if the solution contains 33.6 per cent of sugar and 45.4 per cent

of invert sugar the total solids may be increased to 79 per cent without danger of crystallization. A calculation has shown that after

this process a given quantity of water is capable of dissolving 75

per cent more total sugar after this partial inversion than.it did

before.

For many purposes so dense a sirup is not required. The investigation has shown that for lesser concentrations greater toler- ances are permissible. For example, if the sirup is to contain but 74

per cent of total sugar, any degree of inversion between 34 per cent

and 79 per cent will yield a sirup which is perfectly stable.

A completely inverted sugar sirup is used extensively in the industries. The research has shown how such a sirup may be readily

and cheaply prepared and how great its density may be without a

resulting crystallization. If invert sugar is concentrated above 69

per cent, dextrose separates in small crystals.

These conclusions have been based on a systematic study of the

solubilities of the various sugars in the presence of each other. In

this study the principles of the phase rule have been applied.

A table of densities of pure invert sugar solutions, extending from

6 per cent to 70 per cent, has been computed and the magnitudes of

the corrections, which must be applied to the Brix hydrometer reading, have been tabulated.
122 KEPOBT OF DIRECTOK OP BUREAU OF STANDARDS.

Solubilities of Dextrose.

The development of the commercial process of manufacturing pure

crystalline dextrose requires a knowledge of the solubilities of the

sugar over a wide range of temperature.

Thus, as a fundamental basis for calculating supersaturation coefficients, for estimating crystallizer performance, and for the more

extended investigation of the effects of nonsugars on the process of

crystallization, the solubilities assume a technical as well as scientific

importance.

This investigation has been brought to completion during the cur- rent year. A complete series of determinations of the solubilities,

extending from —5° C. to 90° C, have been made. The saturated

dextrose solution depresses the freezing point of water to —5°. From

this temperature to that of 50° C. the stable form of crystalline

dextrose contains 1 molecule of water of crystallization; i. e., the

pure solid crystal contains about 9 per cent of water. At 50° there occurs an abrupt transition, and above this temperature the stable

form of dextrose is completely anhydrous; i. e., it contains no water

of crystallization. Under certain conditions, however, this anhydrous

form may be made to crystallize from water solutions at temperatures

much below 50°. The curve representing these solubilities has been

extended even down to 28° C. In the upper ranges the curve has

been extended to 90° C.

Candy Test for Sugar.

There have long been conflicting ideas regarding the suitableness

and applicability of certain refined sugars for the making of candy.

That there is some justification for the ideas concerning the variability of their suitableness has been established. The problem has

been attacked by the Bureau in connection with the analytical study

of refined sugars. A definite result has been attained in the development of a candy test showing a higher degree of precision and

indicating the presence of minute quantities of impurities which

vitally anect the qualit}^ of the product obtained when the sugar is used in the confectionery industry. A new precision apparatus has

been designed for this work, and it is believed that additional information needed to carry this investigation to a successful con- clusion will be obtained.

Baume Scale.

The standard Baume scale for liquids heavier than water, perfected by the Bureau, has now practically displaced all other Baume

scales for scientific and industrial purposes. Scientific opinion seems

divided as to how far the Baume principle should be utilized in the

sugar industry. The plan adopted in the new table, of giving the

Baume value opposite the corresponding value in percentage of

sugar or degrees Brix, has given excellent results. The use of the

more expressive and significant value in percentages of sugar has

greatly increased.

Supplies for the Customs Service.

In view of the fact that many of the sirpplies as well as equipment

used in the laboratories of the 'Customs Service are purchased under

the rigid specifications of the Bureau of Standards and are neces-
r.EPOET OF DIJRJXJTOE OF BUEf^AU OF STA^^DARDS. 123

sarily sent to the Bureau for test, a storeroom was set aside last year

in whicli a supply of these materials may be held ready for shipment. A sudden demand for these materials by any port may now

be met without delay. A number of additional items have been

added to the stock, and at present a supply of such apparatus as volumetric flasks, polariscope tubes, cover glasses, dichromate absorption cells, thermometers, picnometers, pipettes, etc., is kept on hand.

The improved service in securing laboratory supplies which must be

accurately tested has been of material benefit to the entire Customs

Service. For some years it has been practically impossible to secure delivery of volumetric apparatus within any reasonable time limit,

and as emergencies are continually arising in the Customs Service in

which these materials are needed, great embarrassment in expediting

the delivery of merchandise to the customs ports has frequently

resulted.

A suitable supply of sugar weights, as well as sets of analytical

weights, is being accumulated as rapidly as possible. It is a matter

of importance that the weights in use at the customs ports be re- turned to the Bureau at frequent intervals for testing. This can be

made possible only by establishing a suitable reserve supply, to be

held at the Bureau. Increased precision in the work of appraisal in

the Customs Service will necessarily result from this procedure.

The idea has long been prevalent that the polariscope tube, once

it has been accurately adjusted for length, would remain so. In an

investigation of certain discrepancies appearing in the work at vari- ous ports the Bureau discovered that because of the continuous service demanded of these tubes the length determinations could not be

depended upon for more than a year. A sufficient number of tested

polariscope tubes is now kept on hand at the Bureau and it is possible

to have the tubes in use at the customs laboratories replaced at

frequent intervals and the old tubes returned to the Bureau for test. Where inaccuracies exist the tubes are sent to the manufacturer for

readjustment. This procedure has resulted in the saving of a considerable sum annually to the Treasury Department. In the development of this work, and especially in the securing of increased ac- curacy which is essential in the collection of the customs rcA^enues,

the Bureau has had the encouragement and assistance of the officials

of the Treasury Department.

Properties of Quartz at High Temperatures.

The investigation of the physical properties of quartz at high

temperatures has been continued. This includes the precise measure- ment of the natural rotation of light by the crystalline material at

temperatures ranging from 20° C. to 1,500° C, and includes a careful

exploration of the range where quartz recrystallizes and assumes new

crystallographic axes. The investigation of all the physical properties of quartz is of importance from a general scientific standpoint,

both because of its bearing on the problems of geology and because

of its widespread utility in the scientific field in general. It is of

especial interest here because of the fact that the modern saccharimeter is based upon the use of quartz in its construction. A considerable amount of computation has been completed and the data

carefully studied.
124 EEPOET OF DIEECTOK. OF BUREAU OF STANDARDS.

Adjustment and Standardization of Polariscopes.

The work of adjusting and standardizing polariscopes and sac- charimeters has been continued with gratifying results. It has

been necessary to continue the work of adjusting instruments in

addition to standardizing them, as few instruments reach the Bureau

in perfect adjustment. The sugar industry, as well as educational

and research institutions, have been unable for some years to obtain

an adequate supply of new polariscopes. Several excellent types of

instruments have been on the market for a year or more, but in

limited quantities. Many of the instruments sent in for adjustment

are of old types, having a dilferent basis of calibratioh from the

newer types. The Bui'eau has been constantly consulted in regard

to the use of these instruments and has been able to render valuable

service. In connection with the work of adjusting instruments a number of related problems have been solved which promise to be of

value to manufacturers. Among them may be mentioned the preparation of a suitable cement for polarizing prisms and a process of

grinding and polishing the faces of damaged prisms. The Bureau's

facilities have been severely taxed to handle all the instruments submitted, despite the additional facilities Avhich were provided. During the year 73 polariscopes and saccharimeters were adjusted and

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 necessary to

be applied to the scale reading to give the true rotation in sugar

degrees, based on the now widely accepted Bureau of Standards determination of the 100° point of the international sugar scale.

Rotation Dispersion of Sugars.

The natural rotation of the plane of polarization of light is one

of the characteristic physical properties of so-called optically active

substances. The literature in this important field is meager and,

in general, the work that has been done is usually lacking in precision and in nearly every case is referred to a single wave length

of light, namely, sodium yellow. The Bureau has shown that the

green line of the mercury spectrum is far superior to the sodium line

and is coming into more and more general use. All the rotation

constants will be determined for this wave length. The very important rotation dispersion constants for various wave lengths of

light have been almost entirely overlooked.

In continuing this research measurements have been made to determine the rotation dispersion, using solutions of various sugars.

Thus far preliminary measurements only have been made on sucrose,

dextrose, and galactose. One of the principal purposes of this investigation is to accurately measure and record the characteristic

jDhysical constants for the various sugars which are now being produced by the Bureau in a high state of purity. When this has been

accomplished, manufacturers and investigators will have a definite

guide for the purity of their products.

The rotation dispersion was also measured for two submitted

samples of abietic acid obtained from white resin. The constants

were desired for coordination with the other physical and chemical

properties of this substance.
REPORT OF DIRECTOR OTP BUREAU OF STANDARDS. 125

Saccharimeter Light Filters.

A further investigation of suitable light filters for saceharimQters

has been made. The standard filter adopted by the International

Sugar Commission is a layer 1.5 centimeters thick of a 6 per cent

potassium bichromate solution. As pointed out in the previous re- port, this filter has the disadvantages inherent in a solution. A decided improvement would be accomplished if a permanent filter,

such as a colored glass, could be used in place of the solution.

The spectral transmissions of a number of colored glasses from

several sources have been determined, and a glass has been found

whose spectral transmission curve very closely approximates that of

the standard bichromate solution. The readings obtained on the

saccharimeter with a near normal sugar solution with this glass, and

also with a number of others having slightly different transmission

<;urves, have been compared to the readings obtained, using the standard bichromate filter. The observations so far obtained indicate that

there is no difference between the readings obtained Avith a standard

bichromate filter and those obtained with a glass whose spectral

transmission curve closely approximates that of the standard filter.

However, the differences sought after are extremely small, and no

definite conclusions can be drawn until a large number of observations have been made by several observers.

The question of a light filter for saccharimeters is an important

one, and no change will be recommended until conclusive experimental data are obtained.

Standard Samples.

During the past year 88 samples of sucrose and 31 samples of dextrose were distributed. These materials were principally for industrial and scientific purposes. In view of the increased demand for

these materials, both in the laboratories of the Bureau and elsewhere,

equipment with larger capacity is being installed. Similar equipment was studied in commercial operation, and from the information

obtained a plant has been designed and ordered which will permit of

great flexibility. It will make possible the preparation of considerable quantities of the various sugars. The equipment will consist of

a 10-gallon vacuum pan, with condenser, receivers, vacuum pump,

and complete accessories.

Tests on Cover Glasses for Polariscope Tubes.

As a result of the Bureau's work in encouraging the production of

polariscope tube cover glasses in America the Customs Service and

the sugar industry generally are now wholly independent of the

European supply. It is essential that these glasses be very clear

and as nearly free from strain as it is possible to make them. The

fulfillment of the latter condition caused the German-made cover

glass to be very much in demand in the United States for many

years. During the past year large numbers of these glasses were

tested for optical homogeneity and absence of optical activity, and

it has been very satisfactory to note that practically all of them

were of American manufacture.

mn
126 ' REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Investigation of Strains in Glass by Polariscopic Methods.

Glass, when strained through improper annealing or by the application of an external force, becomes inhomogeneous. This concl.itioii

results in variations in the density and refractive index throughout

the specimen, rendering it unfit for optical purposes. To a great

extent such inhomogeneities in insufficiently annealed glass arise

from the existence of regions of compression and tension. These

stresses result from deformations due to a lack of intemperate uniformity in the glass, either while it is being made in the required

form or while it is being annealed.

The only practical method of testing glass for the presence of these

inhomogeneities and the accompanying variations in the index is to

examine it in polarized light and to determine to what degree it is

doubly refracting. To render these tests of practical value it is nec- essary to know the relation of the double refraction and the variations in the index to the stresses producing them. This relation

varies widely with different glasses, making it necessary to investigate each glass individually. Furthermore, since it is practically

impossible to remove all the compressions and tensions from the

glass by annealing it is necessary to determine the effect of their

magnitude and distribution on the performance of the glass when

used in optical instruments. These questions are being investigated

in order to obtain data which will be available in establishing standards for the fitness of glass for optical purposes. A paper on various

phases of this subject is now being prepared.

Thermal Properties of Glass.

In the region where glass loses its viscosity and becomes practically rigid it is found that there is an excessive evolution of heat

in the glass^ on cooling. On heating through the same region there

is an abnormal absorption of heat. The character of these

phenomena is altered considerably b}' the previous treatment of the

glass, whether chilling or annealing. In many respects their character suggests that in certain temperature ranges some molecular

transformation normally takes place in glass which can be suppressed by rapid cooling. This effect may account for some of the

variations in the refractive index in an insufficiently annealed glass.

For this reason a thorough study of the effect of rapid cooling on

the character of this transformation is of extreme importance in

annealing, especially since it has been foimd that a determination

of the temperature at which the heat absorption of glass occurs aids

considerably in the problem of determining the proper temperature

for annealing. A thorough investigation of this effect is now in

progress and certain phases of it have been discussed in an article

entitled "Absorption of heat in glass," published in the Journal of

the Optical Society, volume 4, page 340. Additional data on this

subject will soon be ready for distribution.

Annealing of Glass.

Nearly all types of glass must be annealed in order to remove

objectionable strains acquired in their manufacture. In annealing

optical glass the requirements are exceptionally rigid. For common

glass, however, the annealing need only be sufficient to prevent it
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 127

from breaking spontaneously or in normal use. In order, however,

to anneal the common glasses as easily and economically as possible,

it is necessary to know the annealing temperatures, the minimum

uniformity of temperature allowable, the time required for annealing, and the permissible maximum rate of cooling for each type of

glass.

Investigations are accordingly noAv being carried out by the polarimetric section in cooperation with the pyrometry and optical glass

sections of this Bureau to secure the necessary data on all the factors

which enter into the annealing of common as well as optical glasses.

Hardened Glass.

In hardening glass the process followed is practically the opposite

of that in annealing. In annealing glass the object is to eliminate

as far as possiljlc all strain, while in hardening glass the purpose is

to introduce certain strains properly distributed. Glass so hardened

has been found to be ox value in the manufacture of protective

goggles, windows, etc., where great resistance to mechanical shock

is required. Investigations as to the relative efficiency of the various

methods of hardening glass and of testing such glass have been

begun.

Refractometer in Sugar Analysis.

It has been found that the refractive index of a sugar solution

gives a very close indication of its total solid content, even when the

dissolved solids do not consist exclusively of sugar.

At a meeting of the American Chemical Societ}^ a committee was

appointed to investigate, in conjunction with the Bureau of Standards, the technical uses and limitations of the refractometer as applied to the sugar and glucose industries. ' A member of this

Bureau was made chairman of this committee. The investigation

necessitates the preparation of pure sucrose, dextrose (the methods

for which have already been completed), maltose, ievulose, and invert sugar, the preparation of their solutions in exactly known concentration, and a determination of their respective refractive indices

with the highest possible precision.

On completion of this fundamental work the influence of impurities must be studied, and, if possible, corrections must be applied

to eliminate errors. The pi^actical value of this research lies in the

fact that the refractometric estimation, once the fundamental values

are ascertained, can be carried out Yery simply and rapid•l5^

Commercial Production of Pure Dextrose.

In the previous report there were given the results of the Bureau's

investigation to assist in the development of a method of producing

pure dextrose or glucose on a manufacturing scale. After the suc- cessful completion of the laboratory experiments and the carrying

out of experimental woxic for a large glucose factory by a representatiye of the Bureau an extensive experimental plant was designed,

with the Bureau's assistance, for a large corporation S]:)ecializing in

glucose products. The plant has been completed and successfully

operated, with the result that the corporation is now completing a plant at Chicago, costing approximately $1,500,000, for the manufac-
128 REPORT OF DIRECTOR. OF BUREAU OF STANDARDS.

ture of 2)ractically chemically pure dextrose. The methods and machinery used in the manufacture of granulated sugar are largely

utilized, with the result that the dextrose crystallizes out in beautiful

small white crystals.

Cadmium Vapor Arc Lamp.

The new cadmium vapor arc lamp developed by the Bureau as a source of monochromatic light for polarimetry has not come into general use owing to the scarcity of the element gallium. This element is

indispensable in the manufacture of the lamp. A number of requests

for lamps for research work have been received from European

sources.

Society of Sugar Chemists aj;id Technologists.

The elforts of the Bureau to render assistance in the formation of

an American Society of Sugar Chemists and Technologists have been

chronicled in a previous leport. The growth of this organization

and the interest manifested by all phases of the sugar industry has

surpassed expectations. Previous experience has demonstrated that

an organization of this character invariably opens up new channels

which make it easier for the Bureau to extend its usefulness and co- operation with the industry which the society represents. The new

organization has already proven of material benefit in this connection

and constitutes a section of the American Chemical Society. The interest manifested, results accomplished, and the growth of the or- ganization have justified its petitioning that it be made a self-governing division. At the last meeting 33 technological papers, including

i foreign contributions, and covering every phase of the sugar industry, were presented.

COLORIMETRY.

General Nature and Scope of the Bureau's Work in Color Standardization and Colorimetry.

" Color " is one of the items of interest in describing and specifj^-

ing various materials and objects. It is a fact that the commercial

value of many materials depends in part upon their color. It is,

of course, obvious, on first thought, that the color of a dye or a pigment or a railway signal glass is its dominating characteristic, the

property which first comes to mind when it is thought of. While

less obvious to those unacquainted with the trade in particular commodities, it is also a fact shown by the Bureau's correspondence that

the most varied industries are intensely interested in and concerned

Avith the standardization and control of the color of their products.

Among the objects and materials for which various interests have

asked the Bureau to provide color standards or better methods of

color measurement and specification may be mentioned the following

Railway signal glasses, dyes, paints and pigments, paper, lime, gypsum, flour, tobacco, oils, butter and oleomargarine, ceramic wares,

and others. In fact, it appears from inquiries and requests received

that some one is likely to be interested in specifying the color of

almost any material or object that can be named. Much of this

interest is wholly commercial because the price is dependent upon

color, and the buyer and seller must accordingly have accurate and
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 129

reliable means of specifying this property. Aside from this there is

the purely scientific interest. The botanist requii'es means of describing the colors of his materials, likewise the chemist, geologist,

the ornithologist, and other investigators in various fields. The

anthropologist desires to specify the, color of the skin of various

races and hybrids. The psychologist and physiologist desire to

specify the colors of cards and papers which they use in their ex- periments on vision. The list might be augmented, but these illustrations will suffice for examples. Thus the Bureau's work in colorimetry had its origin in an insistent demand from many sources for

color standardization.

The meeting of these demands in a satisfactory way requires first

of all a vast amount of fundamental research. Unlike older sciences

and arts, the methods and standards of colorimetry are not well

established. There are, in general, no ready-made standards, instruments, and methods to be recommended. The work, therefore,

consists largely in the development and testing of suitable methods,

instruments, and standards. The problems met are of unusual diffi- culty, involving questions in physics, psychology, and physiology

at the same time. Although we may speak of the " color of an

object," color is strictl}^ a sensation determined by the nature of the

light entering the eye. Fundamentally, then, the specification of

color from an obective point of view takes the form of a specification

of the light emitted by a light source, the transmission of a transparent material, or the reflection of an opaque material. A large

part of the work is accordingly the measurement of such characteristics by spectrophotometry or other means. In addition, attention

must be given to the study of color vision.

Although the importance of prosecuting research in this field miist

be particularly stressed, it should also be noted that many practical

routine tests are currently made, in so far as knowledge and methods

are available. Thus, railway-signal glasses are tested by a perfectly

well-established method of determining their transmission for lights

of various hues. Glasses designed to protect the eyes from injurious

radiant energy and " ray filters " for photographic work are tested

in the same way. The spectral distribution of light sources is likewise a matter of well-established test. The spectral reflection of

paints, dyes, fabrics, and other materials are determined on request.

Because of the undeveloped nature of the subject, as well as its

limited facilities, the Bureau is able to satisfactorily meet only a small part of the demands made upon it in this field of standardization. But the subject is being systematically developed, and practical requirements are being met as rapidly as these limitations will

permit. For other information on progress, reference is made to

previous reports, 1913 to 1920, inclusive.

The Standardization of " White Light."

It is obvious that the cardinal problem of color standardization is to fix a standard for " white." This is the keystone of the whole

structure. We approach the problem from the viewpoint of common

knowledge. and common sense. Simlight is commonly called "white

light," but the light of a candle or oil flame is almost as generally

64984—21- 9
180 REPORT OF DIRECTOB OF BUREAU OF STANDARDS.

also called white, if the two be immediately' compared, the formei^-

will appear intensely bhie, the latter intensely yellow. Among common electric glow lamps we may arrange them in order as to color

between the candle and the sun. Thus, carbon filament, vacuum

tungsten, gas-filled tungsten. The light of the carbon arc is blue as compared to the gas-filled tungsten glow lamp, but yellow as compared with the sun. The sun appears yellow in comparison with

some of the stars and blue in comparison with others. Moreover,

the color of sunlight varies over wide limits during one day and during the year. Wliat. then, shall we take as a standard " white light " ? One method would be to arbitrarily say without further discussion

that the average noon sun (or some other source) is white; that is,

settle the question by definition. It is perhaps more reasonable to

define white light as the light (of an ideal complete radiator) which

will evoke the hueless sensation commonly called Avhite or gray by

the average observer under certain standard conditions, contrast

and fatigue effects being eliminated, and then find this light by ex- periment. Even if we do not set up such a definition prior to the

experimental determination, it must be admitted that the results of

such an experimental determination Avould be of the utmost interest

in considering the formiilation of the definition. A preliminary determination of this kind Avas completed during the year. The results

were communicated to the American Phy^sical Society and the Optical Society of America in December, 1920. (Jour. Op. Soc. of

Am., Mar., 1921, p. 205.) The complete account of this Avork is noAv

in press as a Bureau of Standards Scientific Paper. Since only' four

observers were included in this preliminary determination, no final

standard can be definitely recommended as yet. The results of these

four observers, hoAvever, indicate tliat white light is fairly well represented : (1) Theoretically, by the light from a complete radiator (or

nonselective incandescent solid) at a temperature of about 5.200°

absolute centigrade; (2) ])ractically by the light of the average noon

sun at Washington. The develo])ment and practical testing of an

experimental method suitable to attack the problem is regarded as a more important result than the mere finding of these preliminary

values. It is now desirable that similar determinations be made

by a large number of observers OA^er a period of time, and that the

conditions of the experiment be varied in seA^eral ways.

The Color of Various Illuminants.

The standard white light being established, it is next important to

grade other illuminants to color. Work on this problem is in

progress, in cooperation with other scientific and technical laboratories. An apparatus for providing standard light such as would be

emitted by a complete radiator at very high temperatures has been

cleA'ised aiid described. (Jour. Op. Soc. of Am., March, 1921. p. 178.)

This apparatus is now in practical use in the measurement of the

" color temperature " of high efficiency gas-filled lamps, the electric

arc, and working standards of " artificial sunlight."

Spectrophotometric data on several high intensity arcs used in

military searchlamps have been piiblished. (Bur. Stds. Tech. Paper

No. 168, August, 1920.)
KEPOET OF DIRECTOR OF BUREAU OF STANDARDS. 131

The Relation Between Color and the Spectral Distribution of Light.

In general, the same color (sensation) may be evoked by light of

many different spectral distributions (stimulus). Thus arises one

of the major difficulties of color standardization. It is a matter of

importance to find what conditions are satisfied by stimuli evoking

the same color. A great deal of data accumulated incident to other

work has now indicated one of these conditions. The subject is too

intricate to be profitably dealt Avith in detail in this report, and ref- erence is therefore made to the published paper describing the relation found. (Jour. Op. Soc. of Am., September, 1920, p. 389.)

A Direct Reading Spectrophotometer for Liquids.

As emphasized in previous reports, the ultimate physical basis of

colorimetry is spectrophotometry. A notable handicap to progress

has been the lack of spectrophotometers suitable for rapid as well as accurate work. Such an instrument is needed particularly now in the

vegetable-oil and dj^estuff industries. A new instrument has therefore been designed at the Bureau and constructed in its instrument

shop. This instrument has been exhibited to the American Oil

Chemists Society and the American Physical Society. It has also

been described to the Washington section of the American Chemical

Society, and will probably be exhibited at the Chemical Exposition

next September. It has already met with considerable interest among

chemists and oil technologists. (See, e. g., Cotton Oil Press, January, 1921, p. 42, and Chem. and Met. Eng., May 25, 1921, p. 912.)

A leading instrument maker is undertaking its commercial manufacture, and the Bureau is cooperating with this firm in further development of this and related apparatus for spectrophotometric work.

The Bureau of Standards Scientific Paper describing this instrument

is in course of preparation.

A New Study of the Leucoscope.

The " leucoscope " is an optical instrument invented by Helmholtz

and his pupils about 1878, but has been practically unknown and forgotten in recent years. The instrument is of interest in the stud}^

of color vision, and it now appears to have some practical value as an optical pyrometer. At the time of the early work with it the

results obtained could not be correlated and presented to the best

I advantage because of the lack of other data and clear concepts which

' have subsequently become available. During the past year a new

study of the instrument has been completed in the light of modern

i knowledge and ideas, and a report upon this study has been pub1 lished. (Jour. Op. Soc. of Am., November, 1920, p. 448.)

The Spectral Transmissive Constants of Dyes.

The optical transmissive or absorptive properties of dyes in

solution are of primary importance in practical analysis, identification, and standardization of dyes, as well as in a theoretical study

of chemical constitution.

An extensive investigation, the plan of which was given in last

year's report, has been suspended during the past year because of

lack of personnel to carry it on. The results already obtained have

been compiled and are now ready for publication.
132 BEPOET OF DIRECTOR OF BUREAU OF STANDARDS.

The Spectral Transmissive Constants of Vegetable Coloring

Matters.

Some work is being done in cooperation with the Bureau of Plant

Industry, Department of Agriculture, on the transmissive constants

of the pure vegetable coloring matters—xanthophyll, chlorophyll,

and carotin. These data will be of interest in the color grading of

vegetable oils and the chemical estimation of these coloring matters.

The Color and Spectral Transmissivity of Vegetable Oils.

A large amount of data on the color and spectral transmissivity

of vegetable oils (cotton seed, peanut, soya bean, sesame) has been

accumulated as a result of the Bureau's long-continued investigation

of this subject. Fragments of this have heretofore been published.

These data are now being prepared for publication in extenso. They

will be of interest to the oil-refining industry.

The Spectral Reflection of Various Materials.

A usual preliminary to the studj' of the color grading of any

particular kind of material is the determination of the spectral

reflection of a large number of represejitatiA^e samples. Such preliminary^ studies of various papers and of lime, gypsum, and

enamels have been made in cooperation with the technologic sections

of the Bureau dealing with these materials. In the case of lime and

gypsum this has led to the publication of tentative recommendations

as to color specifications. (Chem. and Met. Eng., June 15, 1921,

p. 1054.)

Investigation of the Lovibond Color Scale as Used in the Color

Grading of Vegetable Oils.

A thoroughgoing spectrophotometric and colorimetric examination

of a large set of Lovibond glasses such as are used in the color

grading of vegetable oils has been completed and the results are being prepared for publication as a Bureau of Standards Technologic Paper.

An Examination of the Munsell Color System.

This is a large system of colored charts intended, primarily, for

instruction of art students and used practically as standards in the

color-printing trade. At the request of its publishers the Bureau

has determined the spectral reflection of a number of these standards.

The results have been published during this year. (Bur. Stds. Tech.

Paper No. 167.) In this paper the scale of " value " (artist's term for

luminosity, brightness, or brilliance) is also discussed and certain

suggestions as to the further improvement of the system are made.

REFRACTOMETRY AND OPTICAL INSTRUMENTS.

In addition to the routine tests of optical materials and the performance of optical instruments, this section has devoted its time

primarily to completing the range-finder investigation reported last

year; to a comparative laboratory study of the various precision

jnethods for testing the performance of photographic lenses, with

the object of adopting the most preferable; to developing a series of
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 133

laboratory telescopes of standardized design; to designing a re- fractometer of high precision, a tool polarimeter for precision

analysis of elliptically polarized light, a simple and relatively inexl^ensive range finder for general snrve}^ work ; to an investigation of

the effect of the presence of strain on the performance of large re- flecting prisms ; and to an investigation of a method for illuminating

cross lines in telescopes. The completed activities are summarized

below.

Range-Finder Investigation.

This investigation, which was carried out iii cooperation with the

Ordnance Department of the United States Army and described

in detail in last year's report, was completed during the current year.

It consisted of a laboratory and field test of a number of different

types of.80-centimeter base range finders, the field test being carried

out at Fort Sill, where about 21,000 observations b^^ different men

in the service were made. From these observations both the probable

accurac}"^ of the different types of instruments and the probable

error of the observers were deduced.

Standardized Laboratory Telescopes.

Very acceptable improvements are possible in general laboratory

telescopes from the standpoint of choice of optical parts in Avhich

the number should be reduced to a minimum, interchangeability of

oculars and micrometers, and range in the depth of focus. The

design of three differenct sizes of such standardized laboratory telescopes has been carried ovit for the Bureau laboratories, and the

smallest of the three has been constructed in the Bureau's instrument shop and tested. It has a relativel}^ large range of focus, from

17 centimeters to infinity, and " exit jDupil " w^ell back from the

ocular, so that the e^^e can be placed at a convenient distance from it and yet command the whole field of view ; good definition and color

correction : and a neat mechanical design.

Design of a High-Precision Refractometer.

A refractometer for measuring indices of refraction to the sixth

significant figure instead of the customary fourth or fifth has been

designed and is now being constructed hj an instrument maker. This

refractometer has the same accuracy as a spectrometer and is su- perior to that instrument in that it requires the measurement of only

one angle instead of two. It excels it in that, having a provision for

reversing the circular scale, eccentricity errors are largely eliminated. Compared Avith other designs of refractometers, this one is

self-checking while tlie otliers are not, and being horizontal, does

away with one refraction of the light, which thus permits it to be

used with faint spectral lines, e. g., the G-line, where others fail.

Design of a Universal Polarimeter.

As commonly used, the name polarimeter is generally applied to

an instrument for measuring Avith precision in circular degrees the

rotation of the direction of vibration of plane polarized light by

various media tlirough which it may be passed. Polarized light,

however, has otlier properties wliich must be measured if tbat light
134 EEPORT OF DIEECTOB OF BUEEAT" OF STANDARDS.

is to be precisely specified. In <?eneral. the light vibi'ation is elliptical in form, varying between the rectilinear path (or plane polarized light) on the one liand. and a, circular path (or circularly

polarized light), on the otlier. A universal polarimeter is an instrument, therefore, which will measure any elliptical vibration, the

direction of motion producing it, and the direction of the major axis

of the ellipse. A Tool universal polarimeter has been designed b}' the

optical instruments section in cooperation with the polarimetry sec- tion and built in the Bureau's instrument shop. This polarimeter is the combined application of the half-shade Nicol prism and the

hnlf-shade Brace elliptic analyzer to the Stokes method of ellij^tic

analysis by a variable-azimuth compensator. It will measure ellipses

whose width is 0.2 their length (that is. " ellipticity "=0.2) to an

accurac}' of 1 per cent, and for circularly polarized light, where the

Stokes analyzer fails com]>lotely, it will measure this ratio to 0.05

per cent. For small ellipses it will measure azimuths (direction of

major axis) to 0.02 circular degrees, Avhile for the larger ellipticities

the accuracy of measurement is correspondingly high. The instrument is, furtliermore, designed so that it can be readily converted

into either a Brace elliptic analyzer, which is specially applicable

to the measurement of very small ellipticities, a Stokes analyzer, or

a simple rotation polarimeter.

Intensifying Lens for a Large Aperture Astronomical Reflector.

For the same quantity of light received on the photographic; plate

from each point of the object the necessary exposiire time increases

proportionately to the area of the plate which a given scene covers

that is, the speed varies inversely as the square of the magnification.

At the request of Dr. Harlow Shapley, of Mount Wilson Observatory, an intensifying doublet was designed in the optical instruments section and constructed by the Bureau's ex))ert optician for

increasing the speed of their large reflector by theoretically four

times. This lens was first computed Avith great care and the curves

repeatedly checked during the process of grinding. The laboratory

test of the finished lens was very satisfying, so that the final working test is awaited with confidence.

Design of Cameras for the Navy.

Improvements in the design of a spotting camera and a long-range

motion-picture camera for the Bureau of Ordnance of the Navy

were made in the optical instruments section and the mechanical

modifications carried out in the Bureau's instrument shop. These

improvements related principally to increasing the speed of the

cameras and reducing the mechanical vibrations of the operating

mechanism.

Special Test of Lenses for the Air Service.

Very careful and" complete tests of a number of long- focus higlispeed camera lenses were made for the Air Service of the War

Department, with the object of selecting the kind most suitable

for use. For making these tests it was necessary to design and con- struct larger attachments for the testing apparatus. With this

extra equipment the Bureau is now fitted out for the expeditious

testing of camera lenses of all sizes.
KKPOKT OF DlRl'Xaun OF BUfJEAU OF STANDARDS. 135

RADIOMETRY.

InAestigatioiis in the general subject of thermal radiation have

been confined principally to the spectral transmission of materials,

to the improvement of instruments for measuring thermal radiation,

and to the elfect of thermal radiation upon the electrical conductivity of matter.

Infra- Red Transmission Spectra.

Spectral transmission measurements were made on a series of

animal, vegetable, and mineral oils for the purpose of determining

whether by this means it is possible to detect the adulteration of one

oil by another. For example, cottonseed oil in olive oil. It was

found that the transmission spectra of all these oils are so closely

the same that they are difl&cult and uncertain of identification. This

was, of course, to be expected in view of the principle established

almost two decades ago, that the great groups of chemical compounds, for example, the fatty acids, have similar absorption spectra.

Spectral Transmission Screens.

The ordinary spectroradiometer is not applicable for determining

the spectral energy distribution of sources which are weak in thermal

radiation; for example, of stars, arid of luminescence of terrestrial

objects. It is therefore necessary to resort to various expedients, one

of which is the isolation of wide spectral regions by means of

screens. »Such screens are useful also for producing light stimuli of

large area for botanical, photoelectrical, and photochemical investigations.

During the past year a further search was made for screens having a uniformly high transmission in one part of the spectrum, terminating abruptly into complete opacity in another part of the spectrum. It was found that by suitable combinations of colored and

clear glass, also quartz (all of proper thickness) and 1 centimeter

cell of water, it is possible to determine the radiation intensity in

the spectral region for the intervals between O.Sji, 0.4p., 0.5\i, O.Q^,

0.7(ji,, 1A\)., '2.8[)., 4.1iJ., and 9;;. equaling 0.001 mm.) without involving any important correction for energy losses other than that

of surface reflection. This offers a convenient and fairly reliable

means of determining the spectral energy distribution of stars, also

a means of determining the spectral type of the companion stars of

spectroscopic binaries. For example, preliminary measurements

made with the water cell are to be interpreted as showing that the

companion star of the spectroscopic binary, ^ Ononis, is red and of

too low luminosity to affect the photographic plate.

A Portable Vacuum Thermopile.

Vacuum radiometer containers which are provided with windows

of fluorite or rock salt usually leak. The evacuation changes also as the result of the slow disengagement of adsorbed gases from the

radiometer receiver. As a result of these difficulties attempts to seal

off the vacuum radiometer permanently from the evacuating device

have not been successful.

During the past year a paper was prepared giving a descrii^tion

of a portable vacuum thermopile mounting of glasSj in which the
136 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

evacuator, consisting of metallic calcium in a quartz test tube, is

permanently attached to the container. General directions are given

for operating the device, as well as data on the thermopile, which is

of bismuth-silver. Observations extending oA^er a period of about

seven years are given on the behavior of vacuum thermopiles in

which the vacuum is maintained by means of calcium, which has the

property of combining with gases when it is heated.

Methods for Testing Glasses Used for Protecting the Eye from

Thermal Radiation.

Some time was spent in working out a quick and inexpensiA^e

method for determining the opacity of eye-protective glasses to

ultra-violet rays. The photographic method now used requires sev- eral hours for making such a test. By the new method, which is

radiometric, the test can be made in a few minutes. This method

is based upon the fact that all glasses are opaque to radiations of

wave lengths less than 0.3 /x. It is therefore necessary to examine e^-e- protectiA^e glasses for opacity to ultra-violet radiations only of wave

lengths 0.3 p, to 0.4 [x. Radiations of these waA^e lengths are easily

obtained Avithout employing a spectroscope by simply filtering the

light from a quartz mercury vapor lamp through a suitable glass screen (Corning, G., 586J; thickness, about 2.5 mm.) placed OA'er a A'acuum thermopile or a photoelectrical cell. Measurements of 1 part

in 10,000 are easily obtainable. Avhereas in order to make the tests comparalile with the specifications of the present safet}^ Code for

Eye Protection, an accuracy of 1 part in 1,000 only is necessar3^

If agreement can be obtained on this method of testing glasses for

opacity to ultra-violet radiation, this Bureau could issue to msmufac- turers standardized transmission screens and standardized s;iraples

for check measurements to the ach'^antage of all parties concerned.

Exclusion of Ultra-Violet Solar Radiation from Buildings.

Mention Avas made of this problem in the report of 1919. During

the past year, in collaboration with the Chemical DiAdsion, varnishes

were prepared and the ultra-violet absorptivity determined. The

material is to be used on the AvindoAvs of balloon hangars to preA^ent

the ultra-violet rays of sunlight from injiiring the balloon fabric.

It A\'as found that one or two coats of a good spar varnish containing to 10 per cent asphaltum varnish, applied to ordinary window

glass, is an effective means of eliminating the iiltra-Aaolet from sunlight. A single coat of spar varnish containing 5 ^Der cent asphaltum

varnish, dried in a horizontal position, transmits less than 10 per

cent of the ultra-violet solar radiation of all wave lengths less than

405 millimicrons.

Photoelectrical Investigations.

During the past year further investigations Avere made on the

spectropliotoelectrical sensitivity of substances. One line of attack

Avas the subjection of the photoelectric substance (molybdenite, stibnite) to electrical treatment: also to heat treatment for scA^eral hours

at various temperatures up to 600° C.

In the temperature range up to 500° C. sIoav heat treatment has

no definite effect upon the intrinsic i^hotoelectrical sensitivity. At
KEPOKT OF DlItKCXOK Ol" BUKKAL' OF STANDAKDS. 137

temperatures above 000° C. the sensitivity appears to be permanently decreased or entirely destroj'ed.

The general experience is that stibnite becomes photoelectrically

insensitive on melting and recrystallization. It is therefore of interest to lecord that a sample of stibnite ^vhich had been melted and

recrystallized (the surface being covered with patches of acicular

crystals) was found to be photosensitive, the spectrophotoelectrical

reaction being the same as that of the original crystal. The photoelectrical sensitivity of stibnite and of molybdenite was not affected

by passing alternating current through the material either for long

or short periods.

An examination was made of the spectrophotoelectrical sensitivity

of the mineral proustite, which is a double sulphite of silver and

arsenic. The reaction of this mineral was found to be entirely different from that of silver sulphide. At room temperatures the photoelectrical reaction of proustite is confined practically to the xdtra

violet. At low tem})eratures the intrinsic sensitivity is greatly increased throughout the spectrum, and the maximum of the photoelectrical reaction is localized in a band at 0.578 \i. In last year's rej)ort attention was called to the discovery of a sample of molybdenite which had a photonegative reaction, depending upon the wave length of the exciting light as well as upon

the magnitude and direction of the current through the crystal.

Since then further observations were made in another sample of

molybdenite which exhibits this photonegative property. This particular sample is unique in that at room temperatures the photoelectrical response is proportional to the intensitj'^ of the light

stimulus. Moreover, the spectrophotoelectrical reaction in cjuite uniform throughout the visible spectrum to 0.75ja, followed by a rapid

decrease in sensitivity to zero bej^ond At —80 to —100° C^. the

jDhotonegative reaction appears and it is similar to that previously

observed. All the new data are in agreement with the general characteristics of spectrophotoelectrical sensitivity in solids, foi-mulated

in last year's report.

DISPERSOIDS.

Intermediate betwen the general properties of matter, usually con- sidered the field of physics, and the specific properties chiefly studied

by chemists are the properties of substances dispersed in the form of

fine particles (dispersoids) and as minute cellular structures (colloids). There has recently arisen an appreciation of the great industrial importance of such substances, comprising as they do practically everything met with in every-day life, from living tissue to

potter's clay or " movie " films. Chemical reactions are usuall^?^ considei'ed as depending only upon the relative masses of the reacting

substances and not upon their surfaces ; but when such s^'stems have

not reached thermodynamic equilibrium (and this is of common oc- currence in industrial processes) transformations are taking place at

the surfaces between the substances. Now, the fine jjarticles of

dispersoids and the thin films forming the minute cells of colloids

present enormous surfaces, so that the properties of surfaces _may

here be of more importance than those of masses. Indeed, it is

found that dispersoids of widely different composition present com-
138 REPORT OP UIRKCTOK OP BUPvEAU OP STANDARDS.

mon characteristics, due to the similarity of all surface phenomena.

The systematic study of the properties of matter forming natural

surfaces is of fundamental industrial importance.

Stratified Soap Films and Molecular Reality.

_ The structure of stratified soap films has been studied in collaboration with Prof. Jean Perrin, of Paris. The black spot is just two

molecules thick, and the stratified layers increase in thickness in steps

of two molecules. This work is new and very striking evidence of

the existence of molecules and may become of practical importance

in connection with the problem of lubrication at low speeds and high

pressures.

Ultramicroscopic Study of Varnishes.

In connection with an extended investigation of the properties of

varnish, undertaken by H. A. Gardner and P. C. Holdt, of the Institute of Industrial Research, for the Paint and Varnish Manufacturers' Association (in which several other sections of the Bureau

have cooperated) ultramiscroscopic and turbidimetric studies of a

series of varnishes have been made. This work is reported in Circular 127 of that institute.

Work on a Turbidity Standard.

The question of a turbidity standard for water analysis is being

further studied. Curves have been obtained for the rate of settling

of particles of different sizes, giving the size distribution of sus- pended particles. A report of this work was given before the American Water Works Association in Cleveland, June 9, and will be

published in their journal.

INTERFEROMETRY.

The principle of interference of light waves has been applied in

calibrating standards of length and in measuring the changes in such

standards with time, temperature, and heat treatment. It has also

been used in determining the changes in the physical properties, such

as expansivity, refractive index, and density of substances. Very

precise results are obtained due to the extreme sensitivity of the

methods.

Thermal Expansion.

Using interfei-ence methods, the thermal expansion of small

samples, 1 to 10 millimeters in length, can be accurately determined.

During the past year measurements have been made on a large number of samples of glass, tempered steel, cast steel, monel metal, porcelain, " sealing-in " wires, etc. A description of the method and apparatus and the measurements made on several different kinds of glass

was published in Bureau of Standards Scientific Paper No. 393 and

in the Journal of the Optical Society of America, May, 1920.

Calibration of Length Standards.

Precision gauges which are used as length standards in machine

shops are calibrated by comparison with the Bureau's end standards.

These end standards have loeen calibrated by comparison with the
REPORT OF DIHEOTOK OF BUEBAU OF STANDARDS. 139

:standard light waves. A description of the methods and apparatus

used in determining the length of end standards and for making the

comparisons between end standard and precision gauges was published in the American Machinist, September 30, 1920, and as a Bureau of Standards Scientific Paper.

Ruling of Line Standards, Using Light Waves as Fundamental

Length Standards.

Apparatus has been constructed for ruling line standards, using

light waves as the fundamental length standard. Scales correct to one one-hundred-thousandth of an inch have been ruled. With bettercontrolled mechanical conditions, more accurate results can be

obtained.

Index of Refraction of Glass.

Measurements of the variation of the refractive index and dispersion with temperature have been made on several different types of

optical glass. The glasses were tested up to their softening temperature, which varied from 500 to 600° C. All showed an increase

in refractive index with rising temperature or decreasing density.

A paper describing the results of this investigation will appear

shortly.

Testing of Plane Surfaces.

The planeness of optical surfaces is most accurately tested by means

of the interference fringe seen in monochromatic light. The methods

and apparatus used in making such test are describeji in an article

published in the Journal of the Optical Society of Amex'ica, November, 1920.

PHOTOGRAPHIC TECHNOLOGY.

Aside from the important problem of increasing the speed and

resolving po wer and also improving the contrast results to be obtained

from photographic plates and printing out papers, the next in importance is i^robably that of developing methods for testing these

characteristics so that different operators will arrive at the same

conclusion as to the relative value of given photographic materials.

Accurate measurements of the light sensitive qualities of photographic materials are very difKcvilt to make and may be very unreliable, first, becaiise of the lack of complete knowledge of the

complex laws to ^^hich the materials are subject and the complicated

apparatus required, and second, because of the variation in the meas- urements obtained fiom materials which have been apparently subjected to identical treatment and which is found not only in materials of the same brand taken from different packages, but in materials taken from the same package, and even in different parts of

the same piece. Such a condition is not so surprising when the

extraordinary sensitiveness of modei'n photographic material is taken

into account. These various reasons account for the slow development of standardized methods of testing photographic materials.

The Bureau believes that the time has come when standardized

methods can best be introduced and is therefore giving, in its photographic laboratory, special attention to sensitometry investigations.
140 KEPOKT OF DJEECTOK OF BUREAU OF STANDARDS.

Sensitometry.

The new sensitometer ]ioted in the last unnual report is completely

described in United States Patent No. 1382272, obtainable from the

Patent Office at 10 cents per copy. This patent having been dedicated to the public the apparatus may be constructed and used by

anyone without payment of royalty.

The filter factor apparatus mentioned in the last annual report

has been described in Bureau of Standards Scientific Paper No. 409,

under the title "A New Method for Measuring Photographic Filter

Factors."

Color Sensitizing of Photographic Plates by Bathing.

This work has been carried on in cooperation with the spectroscopy

section and is described in the report of that section's activities.

SEARCHLIGHT INVESTIGATION.

This section, which was organized to carry out, in coopei-ation

with the Corps of Engineers of the War Department, certain i]i- vestigations in connection with searchlight illumination and to perform necessary tests on search lamps and search-lamp accessories,

was discontinued in February when the Engineer Corps transferred

their activities to the Engineering Testing Laboratory at Schenectady.

Completion of a Focus-Testing Apparatus for Searchlight Mirrors,

iis described in the hx^t annual report, an a])paratus of special

design was being consti'ucted to explore the form of the reflecting

sui'face of searchlight mirrors. This was completed and successfully

used for testing a number of mirrors. The method not only reveals

the \ ariation of the mirror fi'om a perfect form, but at the same

tinie shows directly whether or not this variation is within the

tolerance imposed by the size of the arc. Design of a Simple Refiectometer for Testing the Reflecting Power

of Mirrors.

A simple portable refiectometer for use l)y inspectors and others

in the factory and elsewhere was designed. Repeated calls were

made during the war by engineers for such an instrument. A description is given in the January number of the Optical Journal

of America, under tlie title " The Use of the Ulbricht Sphere in

Measuring Reflection and Transmission Factors."

Effect of Diffusion of Light from a Searchlight Beam.

For the purpose of determining the etfect of the ditl'usioii of light

from a searchlight beam on the visibility of a target, the brightness

of such beams and the amount of polarized light in them, when

using a gold reflectoi' as well as the ordinary reflector, was meas- ured at various directions and distances from the beam. The re- sults of this investigation are embodied in a foi'thcoming publication.

Among the most important conclusions derived is that a gold mirror, which by virtue of its giving less ditfusible light reduces the

briglitness of the background against which the target must be
REPORT OF DinEf'TOE CF BUKEAI' OF STAJJ'DAKDS. 141

viewed, reduces at the same time, hoAvever, the brightness of the

target, so that the latter is less visible with the gold than with the

silver mirror in the search lamp.

TESTING, INFORMATION, AND PUBLICATIONS.

Testing.

A total of about 2,200 tests Avere made, covering the following:

Quantitative spectroscopic tests for minute traces of imi^urities in

supposedly chemicalh^ pure metals: precision tests of polarimeters

and quartz control plates for the same; tests of exchange samples

of raw sugar for the quantity of sucrose and Avater present, sugar

content, and density of molasses; performance of photograpliic

lenses, binoculars, telescope lenses ; precision tests of refractometers,

refractive indices, and light transmission of optical materials;

spectral transmission of various glasses and ray filters, spectral re- flection of paper pulp, standard colored cards, " white enamel,

dyes in powder form and in fabrics ; tests of quartz mercury vapor

lamps and eye protective glasses for both radiation and mechanical

strength ; ultramicroscope tests of dispersive materials ; planeness

of optical surfaces, end gauges used for secondary standards of

length, and thermal expansion of bodies Inwing small dimensions.

Information, Activities in Societies, Etc.

A considerable part of the time of the staff is consumed in imparting information, covering the entire field of optics, to visitors

and by correspondence witli individual investigators, members of

other Government bureaus, and representatives of industrial concerns. The most numerous inquiries are in regard to methods of

making various optical measurements, hypersensitizing photographic

plates, cementing of prisms and lenses, testing strain in optical

glass, silvering of glass, and color grading; also, concerning the vari- ous light filters, lamps for dye fading, and photosensitive substances

for invisible signaling.

During the year the Bureau has cooperated with other organizations, as follows : The Optical Society of America in the standardization of the nomenclature and in the compiling of standard data

needed in spectroscopy, colorimetry, radiometry, and photography.

A representative of the Bureau has served on each of the society's

committees. The American Institiite of Graphic Arts in the standardization of process color printing. The Bureau's part in this has

consisted in determining the spectral transmission of filters and the

spectral transmission of inks submitted by the Institute. A representative of the Bureau has served on their committee. The American Oil Chemists Society on the Color Grading of Vegetable Oils.

The society's committee on this subject held one meeting at the

Bureau. (See Cotton Oil Press, September, 1920, p. 49, and January, 1921, p. 42.) At the request of this committee an intercomparison of IG glasses used as color standards for grading oil in

different laboratories was made at the Bureau and the results published. (Cotton Oil Press. January, 1921, p. 43.) The Calco Chemical Co. on the spectral reflection of dyed fabrics. The Bureau of

Mines, studying questions relating to the optical properties of smoke

and dusts. The American Chemical Society, to investigate the techr
142 I'.EPOET OF DIRECTOR OK BUREAU OF STANDARDS.

nical uses and limitations of the refractometer as applied to the

sugar and glucose industries.

Publications.

The following publications have been issued during the year bymembers of the Optics Division staif

Measureiiujnt of wave lengths (W. F. Meggers). Dictiouai-y of Applied

Physics, Sir Richard Glazebrook, editor.

Wave-length measurements in arc spectra photographed in the yellow, red,

and infrared (F. M. Walters), B. S. Rci. Paper No. 411. Wave !eu,gths longer than o,.500A in the arc spectra of yttrium, lanthanum,

and cerium (C. C. Kieis), in press. Standard wave len,gths (W. F. Meggers), .Tour, of Op. Soc. of Am., July, 1921.

Interference measurements in the spectra of argon, krypton, and xenon (W. F. Meggers), in press, pre.sented before American Physical Society, Washington, D. C, April, 1921. Xew lines in the spectrum of oxygen (C. C. Kiess), publications of the American

Astronomical Society, vol. 4, p. 170, September, 1920 ; presented before American Astronomical Society in Septemlter, 1920. at Northampton.

The excitation of the enhanced spectrum of niagnesium in a low-voltage arc (Paul D. Foote, F. jNIeggers, and F. I.. Mohler), Phys. Kev.. in press. Resonance potentials and low-voltage arcs for metals of- the second group of

the periodic tal)le (F. L. MoMer. Paul D Foote, and W. F. Meggers), B. S.

Sci. Paper No. 403

The application of the Clerget method to dilute sucrose solutions (Richard

F .Tackson and Clara L. Gillis), Louisiana Planter, vol. 66, p. 141, Feb. 26. 1921; Facts about sugar. Vol. XII, p. 190. Mar. .5, 1921: and International

Sugar .Journal, \-ol. 23. p. 217, April, 1921. The complex applicalnlity of the modified Clerget method (Richard F. Jackson

and Clara L. (iillis), Louisiana Planter, vol. GO, p. 380. June 11, 1921; Facts

about sugar, Vol. XIII. p. 10, July 2. 1921 ; and International Sugar Journal

(date of tills journal in which article appears as yet unknown).

Preparation of galactose (P'arl P. Clark), .Tour, of Biol. Chem., vol. 47, p. 1,

June, 1921. Absorption of lieat in glass |A. (>. Tool and (i. Kiclilin). Jiuir. Op. Soc. of

Am., Vol. IV, p. 340. September, 1920. Au Examination of the Munsell color system (Irwin (!. I'riest. K. S. Gibson, and

H. J. McNicholas). P.. S. Tech. Paper No. 107; presented at meeting of Optical

Society of America, New York, February, 1920.

Color and spectral comjiosition of certain high-inteusity searchlight arcs (Irwin

G. Priest, W. F. Meggers, K. S. Gibson, E. P. T. Tyndall. and F. J. McNicholas). B. S. Tech. Paper No 168. Note on the relation between the frequencies of complementary hues (Irwin G.

Priest). Jour. Op. Soc. of Am., Vol. IV, No. 5. September, 1920.

Report on cali'oration of sixteen loviboiid red .uiasses (Irwin G. Priest). Cotton

Oil Press, January, 1921. A new study of the leucoscope and its applications to pyrometry (Irwin G. Priest), Jour. Op. Soc. of Am., vol. 4. November, 1920; presented before meeting of the Optical Society of America, December, 192®. The .spectral distribution of energy required to evoke the gray sensation (Irwin

G. Priest), ,Iour. Op. Soc. of Am., vol. 5, No. 2, p. 205, March, 1921; presented

before a meeting of the Washington Philosophical Society, May, 1921; Optical

Society of America, Chicago, December, 1920; in press. A method of obtaining radiant energy having the visible spectral di.stribution

of a complete radiator at very high temiieratures (Irwin G. Priest), Jour. Op. Soc. of Am., vol. .5. No. 2, p. 178. March, 1921.

Infra-red absorption spectra of vegetable oils (K. S. Gibs-on), Cotton Oil Press,

September, 1920.

Relative spectral transmission of the atmosphere (Enoch Karrer and E. P. T. Tyndall), B. S. Sci. Paper No. 389. Preliminary note on the relations between the quality of color and the spectral

disti'ibution of light in the .stimulus (Irwin G. Priest), .Jour. Op. Soc. of Am..

Vol. IV, No. .5. p. .388, September. 1920. Tlie spectral transmissive properties of dyes ; I, of the permitted food dyes in the visible, ultra-violet, and near infra-red (K. S. Gibson, H., ,T. McNicholas.

W. E. Mathewson. E. P. T. Tyndall, and M. Katherine Frehafer), in press.
iPjjjjjp.

REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 143

Abstract of report on iuvestigations of the color and spectral trausmissivity of

vegetable oils (Irwin G. Priest), Cotton Oil Press, p. 95, July, 1920; presented

before meeting of the American Oil Chemists Society, New Orleans, May, 1920.

The cemented telescope olxieclive of Barium crown and flint (I. C. Gardner),

Jour. Op. Soc. of Am.. Vol. IV, No. 5. p. 274, September. 1920.

Positive and negative photoelectrical propertiese of molybdenite and several

other substances (W. W. Coblentz), B. S. Sci. Paper No. 398. Infra-red transmission and refraction data on standard lens and prism material

(W. W. Coblentz), B. S. Sci. Paper No. 41. Present status of the constants and verification of the laws of thermal radiation

of a uniformly heated enclosure (W. W. Coblentz), B. S. Sci. Paper No. 406;

Jour. Op. Soc.'of Am., 5, p. 131. 1021; Ibid., including a complete discussion of

instruments, methods, formula, etc., Glazebrook's Dictionary of Pliysics.

Spectrophotoelectrical sensitivity of pronstite (W. AV. Coblentz), B. S. Sci- Pai>er No. 412. Some general characteristics of si>ectropliotoeIectrical conduction in solids (W.

W. Coblentz), Jour. Op. Soc. of Am., 4, p. 249, 1920.

Physical research methods (Book pulDlished bj' the National Research Council;

light, chapters on ; I, lAght sources, filters, etc. ; III, Spectrometers ; and

VI, Speetroradiometry, by W. W. Coblentz.)

Transmission and refraction data on standard lens and prism material with

special reference to infra-red speetroradiometry (W. W. Coblentz), Rep. to the Op. Soc. of Am. committee on speetroradiometry. Jour. Op. Soc. of Am.^

4, p. 32; 1920.

Instruments and metliods of radiometry (W. W. Coblentz), report to Op. Soc. of

Am. committee on speetroradiometry. Jour. Op. Soc. of Am. 5, p. 259 ; 1921.

A portable vacuum thermopile (W. W. Coblentz). in press. Spectroradiometric investigation of rhc transmission of various substances, II (W. W. Coblentz). in press. Sur I'Espaisseur des lames stratiflees (P. V. Wells) Gautliier-Vilbirs. Pari«,

1920 ; presented l)c1ore the Brit'sh Association at Cardiff, Wales, August,

1920.

On the dilution method of counting luicteria (P. V. Wells), Jour. Wash. Acad.,

June, 1921.

On the theory of the geometric mean (P. V. Wells), in press. Turbidimetry of water (P.'V. \^'ells), presented before the American Watei'

Works Association meeting at Cleveland, June 9, 1921 (Jour. Am. Water

Works Assu, 1921).

^Measurements of the thermal dilatation of glass at high temperatures (C. <t. Peters and C. H. Cragoe), B. S. Sci. Paper No. 393. Tlie calibration and dimensional clninges of precision gage blocks (C. G. Peters and H. S. Boyd). American .Alachinist. Sept. 30. Oct. 7, 1920.

Testing of plane surfaces by interference methods (C. 6. Peters and H. S. Boyd), Jour. Op. Soc. of Am., November, 1920.

A new method of measuring photographic filter factors (R. Davis), Jour. Op. Soc. of Am., Vol. IV, No. 5, September, 1920 ; B. S. Sci. Paper No. 409

.Jour. Roy. Photo. Soc, April, 1921.

! An atlas of photographic negative eniulsions (confidential report) (R. Davis

[ and F. M. AValters, .1r.). Sept. 23. 1920.

j Sens;ton]eter for testing plates and films. Patent No. 1382272, issued June 21,

1921, to R. Dav's. The use of the ulbricht sphere in measuring reflection and transmission factors- (Enoch Karrer). Jour. Op. Soc. of Am., Vol. V, No. 1, p. 96, January, 1921.

The papers listed below were presented before meetino's of sci-

! eutific societies during the year

I Sugar section of the American Chemical Society, Chicago, September, 1920:

Comparative analyses of i-efined sugars (Frederick Bates and associates).

Commercial production of d-niannite (W. B. Newkirk and C. F. Snyder),

(ilass vacuum pan for laboratory use (M. J. Proffitt).

The comjiosition and preparation of a .sugar sirup of maximum solubility

(R. F. Jackson and C. L. Gillis).

I determination of the density of molasses (W. B. Newkirk).

I»eterniination of sucrose and true raffinose in beet products (R. F. Jackson

and C. T>. Gillis).
144 REPOBT OF DIRECTOR OF BUREAU OF STANDARDS.

Sugar section of the Americau Chemical Society. Rocliester, N. Y., April, 1921

Two single tests for the control of the crystallizer and centrifugal machine

work (M. .T. Proflitt).

The determination of color and decolorization in sugar products (H. H.

Peters and F. P. Phelps).

Preliminary note on the causes of caking in sugar (M. J. Proffitt).

Solubility of dextrose in water (R. F. Jackson and C. L. Gillis).

Washington Philosophical Society, December, 1920

Optical basis of Bittinger's camouflage painting (Irwin Q. Priest and M. K.

Frehiifer).

Washington Pliilosophical Society, May, 1921

Self-contained range finders and their errors (I. C. (Jardnert.

American I'hysicul Society, \\'ashington, April. 1921:

Stratified soap films and molecular reality (P. V. Wells).

American Pliysical Society, Chicago, December, 1920:

Expansion of sealing-in wires (C. G. Peters).

Index of refraction of glass at liigh temperatures (C. G. Peters),

Double refraction of slass tubing, etc., as indicating the strains present

(A. Q. Tool and C. G. Eichlin).

Optical Society of America, Chicago, December, 1920:

Further results on the heat al)sorption of glass (A. Q. Tool and C. G. Eichlin).

By invitation the chief of the oolorinietry section gave a lecture

on " Spectral reflection " to the technical staff of the Calco Chemical

Co. in P^eln'uarv, and the chief of the Optics Division gave a lecture

before the Franklin Institute at IMiilaJelphia in April hnd before

the Rochester branch of the American Optical Society at Rochester in May on "The polarinieter and its jn'actical applications.'"

5. CHEMISTRY.

The work of this division includes the investigation of the chemical composition and

purity of materials, studies of chemical properties and constants, researches in connection with methods of analysis, the preparation of specifications for technical materials

for other departments of the Government and for industrial and scientific laboratories. The Chemistry Division has general supervision of all chemical work at the Bureau. In

practically all questions of standardization or research the purity of the materials

involved is an important factor. Much of the work of this nature supervised by the Chemistry Division is described under the appropriate headings elsewhere in this report. ELECTROCHEMISTRY.

Included in this work are studies of electrodeposition used in electrotyping and electroi:)lating, the latter being made up of investigations of zinc, lead, nickel, copper, silver plating, etc.

Electroplating Investigations.

The principal work on electrodeposition during the year has been

in connection with a jilant for the electrolytic reproduction of en- graved printing j^lates at the Bureau of Engraving and Printing,

reference to which Avas made in the last annual report. This plant

has been maintained in satisfactory operation during the year, and

the Bureau of Standards has cooperated in bringing about improvements and economies. The experience gained by the staff' from

contact with actual operating conditions will no doubt be of value

in the study of other processes of electrodeposition and will insure

a better understanding of the problems likely to be met in commercial plants. This Avork emphasizes the need for accurate and reliable

information upon electrodeposition and the value of definite control

work in order to insure uniformly satisfactory products. Even

though the conditions met in this plant were somewhat specialized,

there is no doubt that pi-oblems similar to those there encountered
IIKPOKI' OF initKCTOH OJ' Bl'REAU OF STAKDAKDS. 145

exist in practicallj' every j)lant deA'otecl to electroplating or electrotyping.

One of the jDrincipal reqiiirements of the above process was the

production of a very durable printing surface. Special attention

was therefore paid to the deposition of nickel which would have the

desired hardness and other physical properties. As it was found

that the addition of fluorides to nickel baths has a pronouncetl

effect upon the hardness of the deposited nickel, special attention was

<le"\oted to the study of such solutions. One of the greatest diffi- culties was the development of a simple satisfactory method of analysis for these solutions. The problem was rendered more complicated

by the presence of fluorides, but this experience illustrates the large

amount of research work that may be involved to secure I'eliable

methods of analysis and control.

In connectio.n Avith the study of nickel solutions methods have been

developed for measuring and controlling the acidity or hydrogen-ion

concentration, which factor, it is believed, has an important bearing

upon the character of the deposits produced under any given conditions. It is hoped that through the continuance of this work'

methods may be devised whereby the operators engaged in nickel

deposition may be able to determine and control the acidity by means

of simple comparative tests with appropriate indicators.

As the results obtained with the above nickel solutions were so satisfactory, effoi'ts were made to adapt them to the regular electrotyping

operations. A number of experiments have been conducted on such

solutions at the plant of the Eoyal Electrotype Co., in Philadelphia.

The results thus far obtained are not entirely satisfactorj^ and are principally of value in indicating that it may require considerable

study to define the special conditions to be met in each industry.

One of the greatest needs of the electrotyping industrj^ is the production of " electrotype shells " which will be as nearly flat as possible, so that they will not require an excessive amount of labor in

the subsequent finishing operations. There is considerable field for

study in this direction.

The Bureau is cooperating with the Navy Department in the study

of the deposition of alloys of lead and tin which have proven

especially useful for certain of their requirements. This process is

being carried out successfully on a commercial scale, but there is a need for a study of the conditions whicb determine the composition

and structure of the deposited alloy and for the development of

simple analji^ical methods so that the composition may be readily

measured and controlled. Such work will also be of value in throwing light upon the deposition of alloys in general, a field in which

there is great need for investigation.

The section is frequently called upon to assist various divisions of

the Bureau upon special problems involving the electrodeposition

of metals. These problems are -often of very considerable interest

and in some cases at least may lead to new applications or developJj ments of electrodeposition. In addition a considerable amount of

I electroplating is conducted upon equipment manufactured at the

I shops of the Bureau for the various divisions. While it is not possible to conduct such work upon a very large scale, facilities are 64984—21 10
146 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

available for a considerable variety of work, and the experience

thereby gained is valuable. The increasing need and demand for

reliable knowledge upon electrodeposition is indicated by the large

number of requests which are received for information or publications. Such requests emphasize the need for further research in this

field and for a more general distribution of the Bureau jDublications

relating to it. In the above researches the Bureau has received cordial co- operation from various technical societies, especially from the American Electroplaters' Society, the International Association of Electrotypers, and the American Electrochemical Society. In the latter

organization a division upon electrodeposition is about to be formed,

which will no doubt promote interest in this field by bringing into

closer contact the persons interested in such researches. The expense

for travel involved in attending and addressing the meetings of such

technical societies is fully justified, since the usefulness of research

work is thereby greatly increased. The advisory services of an

experienced electroplater which have been secured- both by visits

and by correspondence have proven very valuable.

It is evident that there is a very large field for further work upon

electrodeposition, and that with such funds as are available or in

prospect it will not be possible to make rapid progress at the Bureau

upon many lines. Up to this time the ])rincipal subjects considered

have been the deposition of copper, nickel, zinc, and lead, all of

which require very much more investigation to place them upon a

definite scientific basis. In addition there is a great need for the

study of the deposition of silver, brass, gold. tin. iron, cobalt, and

cadmium, and other metals which miglit be used to advantage if

they were more thoroughly understood. The National Research

Council has recently undertaken to bring before the manufacturers

interested in electrodeposition the needs and possibilities for work in

this field in order to secure from them financial support which will

permit more rapid progress. If such funds are secured, they will

be devoted to studies upon electrodeposition at the Bureau of Standards along such lines as may be recommended by an advisory committee consisting of representatives of the various technical societies.

The numerous industi'ial applications of elect rophi ting and its importance in determining the appearance and durability of many

finished objects should lead manufactui'ers to support such a moffement.

GAS CHEMISTRY.

Methods of 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. Three

major lines of work have been carried forward by the section during

the year. In the order in which they originated they are: (1) The

testing of balloon fabrics; (2) the application to industrial uses of

the newly developed methods of gas analj^sis depending upon thermal

conductivity; (3) the development of imjjroved methods of producino- hydrogen. Minor problems which have arisen from time to time

will be mentioned after the more important lines of work have been

presented.
REPORT OF DIRECTOR OF BUREAU OV STANDARDS, 147

I

Balloon Fabrics.

The first half of the year was largely occupied by an investigation

of the effect of thread count and finish of the cloth upon the properties of rubberized balloon fabrics. This study was made a joint

investigation by the textile section and the gas section, and the

results obtained were embodied in a report dated January 20 and

entitled "A Study of the Etfect of Thread Count and Finish on

Balloon Fabrics."

Since that report was issued the balloon fabric work has been

largelj^ a matter of routine testing of fabrics. A total of 577 tests were made upon 318 fabrics. The tests made in this laboratory upon

two or three fabrics of exceptional properties led the Bureau to urge

that an extensive investigation be made in an attempt to develop a new type of balloon fabric of superior qualities. An allotment was

secured from the Bureau of Construction and Repair for this purpose. The laboratory facilities for testing fabrics were remodeled

and much improved during the year. These changes were made neces- sary by the return of the instruments borrowed by the Bureau

during the war.

Application of Thermal Conductivity Method of Gas Analysis to

Industrial Uses.

The first peried of development of this method. Avhich the Bureau

confidently believes is destined to become one of the most important

analj^tical methods in industry and research, was described in the two

preceding annual reports. This first period covered the development

of a laboratory instrument and the laboratory demonstration of the

possibilitj'' of applying it to numerous useful purposes. The work of

the second period, which maj' be regarded as beginning approximately^ with the pi'esent fiscal year, has been to meet the requirements

of plant conditions. The first installation made by this section, a

single-point helium recorder at Petrolia, was very satisfactory during

1 the time it was in operation. The 4-point recorder installed at

Langley Field for the purpose of determining all the constituents of

water gas and the two G-point recorders installed at Petrolia were

much less successful.

Aside from some trouble with the recording instruments themselves and an important defect in the construction of the " conductivity unit," which will be mentioned later, the mistake was made

of installing apparatus sr complicated as to require the care of an

experienced operator where no competent man was available for the

purpose, and the importance of the results to be secured did not justify the employment of one. Many details of construction also gave

trouble when applied to an apparatus intended for continuous service. The shrinking of " Bakelite " insulating bushings, which caused

I k^aks in the system, made much trouble until they were replaced by

glass-platinum joints. The use of a spool of manganin wire of poor

(juality Avhich changed resistance on standing is believed to have

I spoiled several months' work. Xevertheless, much has been accom-

' plished by the small force available for this work. An apparatus

j capable of analyzing and recording the compositions of 16 various

j gas mixtures was constructed and calibrated for the helium plant at
148 EEPORT OF DIREOTOK OF BUREAU OF STANDARDS.

Fort Worth, although when installed it was applied to only one. A recorder loaned by this Bureau to the Washington Navy Yard is

in successful operation in connection with the electrolj^ic oxygenhydrogen plant there. The success of this installation has led to a

request from the Bureau of Engineering for the construction of 12

instruments of the same kind for use at other points.

The method has been applied successfully in the laboratory to the

determination of sulphur dioxide, and an apparatus for this purpose

is now under construction. It is to be installed, when completed, at

the sulphuric-acid plant at the naval powder factory at Indianhead,

Md. Two large manufacturers of sulphuric acid have undertaken to

apply the method to the control of their plant operation, but have not

as yet completed the construction of their apparatus.

A recorder was used with much satisfaction for three months in

connection with the experimental hydrogen work at Trenton, to be

described later. This instrument was used under the most trying

plant conditions, the difficulty of sampling and cleaning the gas being quite unusual. The recorder was invaluable in this Avork and

should prove of the greatest service in many industries and investigations, since it enables the operator of a plant to follow changes from

moment to moment which can otherwise be ascertained only after

an hour or more. An apparatus has been designed and partially completed for determining the composition of balloon gas.

An auxiliary device is vmdergoing development which takes the

place of voltmeter or potentiometer in certain measurements and

which gives promise of being useful for many purposes other than

that for which it Avas originally intended.

Hydrogen Investigations.

About a year ago the Bureau was asked to report u])on the practicability of first one and then another process for making hydrogen

for balloon purposes. The investigation of these processes led to

the undertaking of a thorough investigation of the possibilities of

two new processes, one of them largely a development of this Bureau.

Funds were provided for the purpose by the Bureau of Engineering and the Air Service, and arrangements were made for modifying

an existing experimental water-gas plant belonging to the Gas Engineering Co., of Trenton, N. J., to enable this Bureau to try out the

two processes on a commercial scale.

The experiments on one of the methods have been completed.

They demonstrated the possibility of making hydrogen from the

thermal decomposition of oil at a cost much below that of any of

the methods now employed by the Government for this, purpose.

The second method, a modification of the steam-iron process, is even more promising. Experiments on this process will be begun in the near future.

An experimental electrolytic generator constructed by the Air

Service for the purpose of effecting economy in the electrolytic production of hydrogen was tested Avith negative results.

A ferrosiiicon h3^drogen plant constructed for the Navy was

recently tested. Certain modifications of this plant will bo tried

out soon.
EEPOKT OF DIREOTDE OF Bl'REAU OF STANDAKT)S. 149

Airship Slide Rule.

At the request of the Bureau of Engineering an airship slide rule

for simplifying certain calculations necessary in the design of lighterthan-air craft was developed and three sample rules constructed and

submitted to the several bureaus interested. This rule is intended

primarily to give rapid solutions of a few problems of frequent

occurrence in airship navigation, Init it can be used to advantage

in solving a great variety of problems involving lifting powers, volumes, temperatures, pressures, altitudes, and the purity of the balloon

gas. The favorable comments received from various souixes and the

fact that an order was immediately placed by the Air Service for a considerable number of these rules indicate that they have filled a i-eal need.

Bibliography of Gas Literature.

A good start has been made toward compiling a practically complete bibliography of the scientific literature relating to the properties, manufacture, uses, and analysis of gases. This work was

done preparatory to undertaking the preparation of a series of circulars which should present authoritative information on all the

. topics covered. A begiiming has been made upon such a circular on

gas density, including compressibility and thermal expansion. Unfortunately the compiler is leaving the Bureau and it will be ex- tremely difficult to secure a competent successor even if funds were

available for the work. The bibliography is of the utmost value

to the section and to the Bureau, even in its present incomplete form.

Gas Analysis.

Two investigations in gas analysis were started during the year

and both gave promise of important results but had to be abandoned

because of the pressure of other work. One of these, a study of gas

absorption, is of fundamental importance not only in connection

with gas analysis but in the engineering problems arising in every

industry'- in which gas is absorbed or purified.

REAGENTS AND APPARATUS.

In this work may be mentioned the study of methods of testing

reagents and apparatus to be used in chemical apparatus, including

j study of chemical glassware, porcelain, platinum, and platinum subI stitutes.

Chemical Reagents and Apparatus.

Lack of funds has prevented prosecution of the very important

, work of testing chemical reagents. A systematic study of the so- called " analyzed reagents " involves standards of quality and stand-

; ardization of methods of test and is therefore of direct value to

! science and the industries. For this reason means should be provided for prosecuting this work. If means are provided, this study

will' be undertaken in cooperation with the American Chemical

Society and with the manufacturers of reagents. One of the seci tional staff is a member of the American Chemical Society committee on " Guaranteed reagents and standard apparatus," and has

attended several meetings of this committee and assisted in the

preparation of specifications for certain reagents and apparatus.
150 EEPORT or DIRECTOR OF BUREAU OF STANDARDS.

These specifications and the report of this committee for the past

year will be published in a forthcoming issue of the Journal of Industrial and Engineering Chemistr3^ The Association of Scientific

Apparatus Makers of the United States is working in conjunction

with the National Eesearch 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. Considerable progress has

been made in the purification of the metals of the platinum group.

All of the palladium (about 650 grams) of this division has been

refined to a degree of purity equivalent to that of the best material

which the Bureau has received from the manufacturers. About 60

grams of osmium sponge of a high degree of purity has been prepared. All of the rhodium on hand has been subjected to purification. Some difficulty has been experienced in removing the last traces

of lead from all of this material, but it is believed that this work

will be completed in the neaf future, yielding about 400 grams of

rhodium of exceptionally high purity. Some of the metal was con- sidered to be sufficiently pure for use by the Heat Division in the

preparation of a 20 per cent rhodium—80 per cent platinum alloy.

The separation and purification of the iridium in the residues obtained from the Nitrate Division of the Ordnance Department,

United States Army, has been continued. Rhodium and iridium are the most difficult to purify of the metals of the platinum group.

Preliminary work has been started on the separation and purification of ruthenium.

In the purification of platinum notably successful results have

been attained. About 1,100 grams of platinum has been prepared of

a higher degree of purity than any the Bureau has ever obtained

from the manufacturers in this country and abroad. This work has

aroused considerable interest among the users of pure platinum, and

requests have already been received for samples of this material to

be used as a standard for comparison. The Bureau has also been

requested to supply thermocouples made from this platinum and

pure rhodium. For this purpose the highest purity is essential.

Details of the work on the preparation of pure platinum will appear

in a paper in a forthcoming issue of the Journal of the American

Chemical Society.

Some preliminary work has been done in cooperation with other

divisions of the Bureaii on the preparation of the platinum metals

alloys. With the installation of additional equipment now under

way it is believed that some progress will be made in this field in

the ensuing months.

In cooperation with the Heat Division an analysis was made of a platinum-rhodium thermocouple alloy purchased on the open market to determine the cause of its inconstancy at high temperatures.

Tests were made of certain pieces of damaged laboratory ware to determine the cause of failure, but no positive conclusion was reached.

Further work should be done in this field. A sample of platinumiridium tubing used in the manufacture of hypodermic needles was
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 151

examined and found grossly contaminated with iron. Analysis of

a dental alloy sold as containing a certain percentage of gold showed

that no gold was present. Two samples of high-purity platinum

wire were examined for a dental supply company. Tests were made

of metallic strips used in hot-wire ammeters, of miscellaneous laboratory ware, and of a reputed platinum ore. The Bureau advised with the Ordnance Department, United States

Army, in regard to the recovery of platinum from the " contact

mass " used in the manufacture of sulphuric acid in war-time powder

plants.

There has been an increasing volume of correspondence relating

to the. platinum metals. In a letter dated July 15, 1920, the Secretary of War authorized the transfer from the Nitrate Division to

this Bureau of 72.44 ounces of platinum residues previously loaned to

this section.

The United States Assay Office, continuing its cooperation of previous years, has made for the Bureau several pieces of platinum

laboratory ware. Platinum Theft.

About 80 per cent of the platinum laboratory ware stolen from this

Bureau on March 18. 1920, was recovered on March 23, 1921. Assistance was rendered the Department of Justice from time to time

in its investigation and prosecution of the theft of platinum from

the Old Hickorj^ powder plant, near Nashville, Tenn. This assistance

toolc the form of chemical analyses of some of the metal in question

and expert testimony at the trial of the persons implicated.

Miscellaneous Tests.

In cooperation with the manufacturers, tests were made of American-made filter paper, representing quantity production. The re- sults indicated that this paper is satisfactory for most purposes, but

should be improved for the complete retention of very fine precipitates in exact analj^sis. Samples of asbestos were examined for two

mining companies and foimd unsuitable for use in analytical work.

ANALYTICAL METHODS AND STANDARD SAMPLES.

These investigations cover general methods of chemical analysis,

with special reference to methods of standardization and the preparation and analysis of standard samples of iron, steel, alloy steels, ores, brasses, bronzes, chemicals, etc. Standard Analyzed Samples.

The number of standard samples called for during the fiscal year

1920-21 was 4,016, as against 5,676 in the year 1919-20. The distribution was as follows

Irous and steels 2, G18

Brass and bronze 68

Ores 140

Sodium oxalate 281

Naphthalene 72

Benzoic acid ^ 308

Sucrose 87

Dextrose 34

Metals tor melting points 292

Cements for testing sieves 107
152 REPORT OF DIRKCXOR OF BUREAU OF STANDARDS.

The decrease in the number of standard samples issued during

the fiscal year is due to three causes: (1) When Congress failed in

1920 to appropriate for the standard sample work manj^ purchasers

feared that the work would be discontinued and therefore placed

large orders before the close of the last fiscal 5^ear;,(2) the lack

of funds and equipment forced a heavy curtailment of the samples

normally issued to colleges and universities; (3) the present depression in the industries is naturally reflected in a reduced demand for

standard samples. In order that the needs of the industries and of

educational establishments may be adequatel}' 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 Avhole work upon a self-supporting basis. Certainly

only a lack of understanding of the situation could have again led

Congress to fail to provide an appropriation for work which brought

to the Federal Treasury considerable funds, the fee value of the

samples issued during the last three vears having a^'eraged almost

$10,000 per year.

Three new samples were added to the list during the year—No.

51, electric furnace high-carbon steel; No. 52, cast bronze, and No.

53, lead-base bearing metal. Ten exhausted standard sauiples were

renewed as follows : Iron C, 5d ; iron E. 7a ; Bessemer 0.4 carbon

steel, 10c ; Bessemer 0.8 carbon steel, 23a ; nickel steel, 33a ; chromenickel steel, 32a; coppei', 45a; zinc, 43a; cement, 47c; and benzoic

acid, 48a.

Cooperation in the Analysis of British Chemical Standards.

In addition to carrying on the analytical work dealing with the

Bureau's standard samples, considerable analytical Avork was also

done on the British chemical standards. In this work the Bureau

cooperated with British, Scotch, French, and Italian analysts in the

analysis of the British standard hematite cast iron " B," plain carbon

steel " 01," carbon steel " M," and chrome-vanadium-tungsten-cobalt

steel "W."

Cooperation in the Development of Standard Analytical Methods.

During the year the section cooperated with the American Society

for Testing Materials in the development of standard methods for

the analysis of aluminum, for the analysis of light akuninum alloys,

and for the analysis of limestone, lime, and hydrated lime.

Researches in Progress,

A study of the Jones reductor with special reference to the reduction of ir(m, titanium, chi-omium. molybdenum, vanadium, and ura- nium has been completed as regards the first two, and the work

dealing with the third is nearly finished. It is worthy of note that

it has been found that titnnium in any amount can be readily and

completel}^ reduced to the divalent condition, provided a few simple

and readily met precautions are observed.

Another study embraces tlie determination of arsenic in irons and

steels. Various luetliods have been studied and serious errors have

been found in some. .\ modified accurate procedure is now being

tested.
REPORT OF DIRECTOR OL' BUREAU OF STANDAIiDS. 153

kStill another stud}' dealing with the composition of certaia sulj)hides lias been nearly completed. Several sulj^hides have been

found to contain normally Avator of constitution, and 'certain others

obtained in analysis, notably those of iron, cobalt, and nickeh have

been found to possess quite different compositions than those ordinarily ascribed to them.

LUBRICATING OILS, RUBBER, PAPER, TEXTILES, INK, AND GLUE.

This section is concerned with chemical anal^'sis and investigations

of oils, rubber, paper, textiles, ink, glue, airplane dopes, etc., with

special reference to meeting particuhir requirements.

Airplane Dopes.

The decrease in testing and investigation of airplane dopes that

was commented on in hist year's report as a result of the cessation

of war activities was maintained during the past year.

Balloon Fabrics.

There vras, hoAvever. no cessation in the routine chemical examination of .rubberized l)alloon fabrics. Rubberized fabrics have a short life, and their permeability is greater than that of fabric cov- ered with goldbeaters' skins. HoAvever, the skins are difficult to

obtain in the enormous numbers needed, and their application is a

tedious and expensive matter. An investigation Avas therefore

started for the purpose of discovering some material haAang the

desirable properties of the skins but Avhich would l)e easier and less

expensive to apply.

This problem Avas attacked from different directions, and some

\ery encouraging results Avere obtained. A coated fabric of unusually

low permeability was prepared. Exposure tests to determine its

life are still in progress. OAving to the military A^alue of the work,

the results are not published in this report. In connection Avith this

chief ])roblem, Avork Avas done on other matters related to it but

of somewhat less importance.

Rubber.

The routine testing of rubber goods continued to be very heavj'',

and mAich time was given to the preparation of specifications and

further time to the study of analytical methods, the need for which

is great because of the variety^ and complexity of mixtures used in

rubber goods. A more complete account of the Bureau's work on

rubber, including that of tlie Chemistry DiAnsion, is giA^en on

page 199.

Textiles.

Most of the Avork in textile chemistry had to do Avith the routine

examination of rope, tAvine, flax, and asbestos packings, sized cloth,

wool and cotton mixtures, and tlie testing of A^arious dyed fabrics.

Some special Avork Avas done ou absorbent cotton and on a large

series of samples of haircloth intended for use in the production of

cottonseed oil. Of great interest Avas the examination of certain sealskins to determine how the}'^ had been dyed.
154 REPORT OF DIRECTOR OF BITREAL' OF STANDARDS.

Writing and Copying Inks.

A great man,y writing and copying inks were analyzed and tested

to guide the General 'Supply Committee, the Panama Canal, and the

Post Office Department in making aAvards to contractors. Throughout the 3'ear many delivery samples were also tested.

It was noted a year ago that the use of concentrated inks and of

ink tablets and powders was on the increase. Within the past 12

months feAver tablets and powders but more concentrated inks were

tested than during the preceding year. For the ordinary user these

. present no particular advantage over writiiig fluid. Large users of

ink, and especially those who distribute to branch offices from a central agency, save by needing less storage space, by lessened breakage

from freezing and other causes, and by lower cost of shipment.

Black tablets and powders are not recommended for permanent

records unless they contain the ingredients of an iron gallo-tannate

inlc of good quality and proper strength.

Stamping, Marking, and Related Inks.

Many samples of inks for use on stamp pads and duplicating

machines, as well as inks for marking and stenciling, were examined.

They were tested to find out whether they were suitable for the purposes intended.

Printing Inks.

Very few samples of printing inks were received for routine ex- amination. However, a number were analyzed for the Public Health

Service in order to find out, if possible, why inks of some colors cause dermatitis, while others have no bad effect upon the skin.

Typewriter and Similar Ribbons.

Large numbers of typewriter and similar ribbons were tested for

awarding contracts ancl for checking deliveries. The ribbons were

for use on typewriters and adding machines chiefly. The quality of

the fabric and of the ink must be determined.

Carbon Paper.

Many samples of carbon paper were examined daring the year.

Among the factors to be considered are the thickness and quality of

the paper, the amount and character of the coating, the permanence

of the copy, its freedom from smudging, and the number of copies

which can be made.

Glue, Mucilage, and Paste.

From time to time throughout the year samples of these matei'ials,

glue, mucilage, and paste, were tested.

Lubricants.

As has been the case for years a great many lubricating oils and

greases were examined. The testing has been simplified by the practically universal adoption of the specifications, and methods of the

committee on standardization of petroleum specifications. Formerly

when the specifications Avere more varied in character the testing

laboratory was put to more trouble than at present.
^B^^ REPOIIT OF DIKECTOR OF BUREAU OF STANDARDS. 155

The oxidizing effect of air upon peti'oleum oils is cominj? more

and more to be recognized as something which can not be ignored and

which should be considered in the laboratory. In addition to its influence upon the behavior of the oils in internal-combustion engines,

oxygen is the cause of the formation of sludge in transformer oils.

There are also indications that the deterioration of turbine oils is

at least partly due to oxidation.

A studj^ was made of a series of metals and their oxides, etc.. in

order to determine their effect upon the rate of oxidation of two

typical oils. An account of this work will appear in the Journal

of Industrial and Engineering Chemistry.

METALS, CEMENTS, 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, asphalts, asphalt

roofing papers, roofing felt, etc.

Built-Up Bituminous Roofing.

The term " built-up bituminous roofing " is applied to that type of

roofing which is constructed on the job from successive layers of rag

felt saturated with either asphalt or coal tar and cemented together

either with asphalt or coal-tar pitch roofing cement. There are numerous types and different methods of constructing this roofing.

An investigation was made to determine the best materials and

methods for constructing this type of roofing in order that specifications may be prepared for the use of the Government purchasers of

these materials, architects, engineers, contractors, and the general

public. This type of roofing is being used to an increasing extent,

and requests for specifications have come from the Supervising Architect's Office, Panama Canal, and the War Department. The only

specifications so far available have been those issued by interested

manufacturers, so the importance of Government specifications is obvious.

This investigation included the field of inspection of roofs giving

both good and poor service and which had been in service for from

3 to 46 years. One hundred and seventy typical jobs were selected

and inspected from a list of approximately 700 roofs. These jobs

were selected from different sections of the country in order to ascer- tain the effect of different climatic conditions upon similar materials

and to determine the relative merits of different local methods of

constructing similar types of roofs. Roofing conditions in the localities selected were also investigated and their bearing upon quality of

the work turned out was noted. In addition to the jobs originally

selected, roofs which were in the course of repair or construction and

which were run into by chance were also inspected. Also in each

locality visited a general survey of the roofing was made from the

tops of high buildings and roofs selected for more careful inspection.

Detailed information on each roof was obtained, including the

method of construction, date laid, and cost of maintenance, which

information in all cases was verified from as many sources as possible.
156 REPORT OF DIRECTOR i)V BL'RKAC OF STANDARDS.

Numerous samples were taken which hav.e been examined in the

laborator3\ This information is now being arranged for publication as a technologic paper.

At the request of the Supervising Architect, which oifice is the

largest Government user of built-up roofing, tentative specifications

were prepared for asphalt and coal-tar saturated rag felts and asphalt

and coal-tar pitch for use in constructing slag and gravel surfaced

roofing on inclines not exceeding 2 inches to the foot. These specifications were submitted to manufacturers, roofers' and manufactniers' associations, and others interested for their criticisms and

comments. Numerous criticisms and suggestions of merit were re- ceived which Avill be considered in the final draft of these specifications.

Prepared Roofing, Plastic Cement, and Roof Coating.

The specifications which were prepared for these materials last year

were furnished recently to the Quartermaster General's Office for

use in a $300,000 purchase of these materials for cantonment work.

Numerous samples of these materials have been tested for this office.

Concrete Drain Tile.

An investigation has been started to determine whether concrete

drain tile can be coated, impregnated, or otherwise treated with

substances which are of themselves resistant to alkali waters and

which will prevent the disintegration of concrete tile so protected

and exposed in the alkali soil districts of the West. A number of

tile have been treated with hot and cold asphaltic dips and have

been exposed in this laboratory to 10 per cent solutions of sodium

carbonate, sodium sulphate, and magnesium sulphate. No results as

yet have been obtained.

Mastic Flooring.

At the request of the Supervising Architect's Office an investigation was undertaken to obtain information for the preparation of

specifications for the material used for asphalt mastic flooring.

Asphalt mastic is to be used as a substitute for maple flooring in the

mail sorting rooms of post offices. Samples of materials from the

three leading manufacturers have been examined to determine their

composition and properties. Physical tests will have to be made and

some performance tests developed for use in the specifications con- templated.

Black Ship Glues (Calking Pitch, Marine Glue).

At the request of the Panama Canal a number of samples of black

ship glue were examined in order to obtain information for the

preparation of specifications. This work is not completed.

Smokestack Paints.

A large number of samples of smokestack paints were tested for

the Navy Department and the United States Shipping Board. This

work required the development of a method for testing the heat re- sistance of these materials.
KEPOKT OF DIRKCIOE OF BUREAU 0¥ STAICDARDS. 157

Belting Compounds.

In connection with Division VII-4 investigation of belting for the

Post Office DejDartment samples of saturating and coating compounds

>vere examined to determine their composition. Most of these materials were nonbituminous in character and consisted of paraffin,

light lubricating oil, rosin oil, raw and boiled linseed oil, oil paints,

giitta balata, etc. Lime Investigation.

Work on the investigation of methods of determination of available lime in quick and hydrated limes requested by the Interdepartmental Conference on Chemical Lime, which was mentioned as in

progress in the report of the preceding year, has been completed.

As a result of the work of the cooperating analysts of the Geological

Survey, the Bureau of Chemistry, and the Bureau of Standards the

conference agreed that none of the seven methods examined were

-satisfactory. Since of these methods,' however, the Scaife method

and the sucrose method gave some promise, investigations were con- tinued by this laboratory. After determining the effect of variations

in procedure upon typical lime samples a modified Scaife method

was evolved which gave values sufficiently uniform for commercial

purposes. Results obtained by the method in this laborator}^ have

been corroborated by the Bureau of Chemistry. The modified

method has been approved by the Interdepartmental Conference and

incorporated in specifications to be published by the conference. The

method has also been submitted to subcommittee V of committee

C-7 of the American Society for Testing Materials, and is being investigated by the members of that committee. The work done has

been summarized for publication.

Miscellaneous Work.

The Bureau has also been consulted by the Government and other

departments on other problems connected with the use of bituminous

materials. Some of these are the Nitrate Pit, at Savanna, 111., the

Lincoln Memorial Pool, and the roofing on the Interior Department

Building, and on various buildings at this Bureau. In connection

with an investigation of colorless waterproofing compounds (nonbituminous) under conduct of the cement section, samples of these

materials are being examined. For the same division considerable

work was done in several fields—analysis of alkali water and soil;

waterproofing and floor-hardening compounds, sand and cement mixtures from the Johnson mixer ; determination of the so-called supercement containing tannic acid ; and a series of comparative analyses

of various brands of Portland cement from Poland, Sweden, British

Columbia, and elsewhere, which showed considerable difference in

chemical composition compared with a representative type of American cement.

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.
158 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Interdepartmental Committee on Paint Specification Standardization..

This committee, whose work was referred to in last year's report,,

has continued active and has now issued a sufficient number of specifications to be of decided use in general structural painting. New

specifications will be added to this list from time to time, and the

existing specifications will be revised as the need arises, it may be

noted that not only have various branches of the Government service

adopted many of these specifications but the American Societ}^ for

Testing Materials will adopt certain of them and large users oxitside

the Government are using some. Some manufacturers are making

a point of advertising their goods as meeting these specifications.

CHEMICAL TESTING.

The number of chemical tests made in the chemical laboratories

during the fiscal year was 7,941. Distribiited by types of materials

the tests were as follows: Ferrous metals (irons and steels), 664; nonferrous metals, alloys, and c'oated metals. 866; cement and cement

materials. 1,071; bituminous products (including creosotes, etc.).

730; varnish materials (including shellacs), 426; paint materials.

733 ; lubricants, 373 ; soaps, nondrying oils, and metal polishes, 428

inks and related office supplies, 850 ; balloon fabrics, 266 ; rubber. 655 ; leather, 8; textiles, 479; miscellaneous, 392.

The tests were made for A'ery many Government bureaus and establishments and for States, municipalities, and private parties, as follows: Agriculture, 7; Commerce, 4,044 (this includes samples re- ceived from other divisions of the Bureau for chemical tests) : Interior, 22 ; Labor, 9 ; Navy. 246 ; Post Office, 380 ; Treasury, 426

War, 932; United States commissions and committees, 252 (including

United States Shipping Board, 240) ; General Supply Committee,

668 ; Panama Canal, 845 ; other independent establishments, 60 ; State

and municipal institutions, 26; private parties, 24.

PUBLICATIONS IN CHEMISTRY.

The following papers emanating wholly or in part from the

Chemistry Division were published during the year

1. Miscellaneous publication No. 46, War work of tlie Bureau of Standards.

2. Scientific Paper No. 390, The two commou failures in the Clark standard

cell.

3. Technologic Paper No. ISO, Causes and pre\ ention of the formation of non- condensible pases in ammonia absorption i-efrigeration machines.

4. Inflammability of jets of hydrogen, published in .Tour. Indus, and Eng.

Chem., 12. p. 1098 : 1920.

5. The application of the thermal conductivity method to the automatic

analy.sis of complex mixtures of gases, published in .Jour, of Indus, and

Eng." Chem.. 12, p. 894 ; 1920.

6. Technologic Paper No. 190, Notes on black nickel-plating solutions.

7. Specification and inspection of electro]ilating for the automotive industries,.

published in Automatic Industries, 44. p. 1289; 1921.

8. The use of fluorides in solutions for nickel deposition, published in Trans.

Am. Elec. Soc, 39, p. 227, and Chem. and IMet. Eng., 35, p. 1109; 192L

9. The preparation of pure platinum, published in .Tour. Am. Chem. Soc., 4.3, p. 1268 ; 1921.

10. New deoxidizers for steel, published in Chem. and Met. Eng., 23, p. 879;

1920.

11. Determination of iron by the cupferron method, published in .Tour. Am.

Chem. Soc, 43, p. 847; 1921.
REPORT OF DIRECTOR OF BUREAU OF STAKDARDS. 159

12. Circular No. 14, sixth edition. Analyzed irons and steels—Jletliods of

analysis.

013. Circular No. 26. fourth edition, .\nalyzed iron and managanese ores

Methods of analysis.

14. Circular No. 40, third edition, Sodium oxalate as a standard in volumetric

analysis.

15. Volatilization losses of phosphorus during evaporation of phosphates with

sulphuric acid or fusions with pyrosulphate, published in Jour. Am.

Chem. Soc, 42. p. 2609 ; 1920. . 16. Determination of antimony in rubber goods, published in Kubber Age and

Tire News, 8, p. 104; 1920.

17. Circular No. 38, fourth edition, The testing of rubber goods.

18. Technological Paper No. 177, Sulphur in petroleum oils. 19. Circular No. 99. The carbonization of lubricating oils. 20. Improved method for the determination of total sulphur in rubber. piil>- lished in Rubber Age and Tire News, 9, p. 47 :. 1921.

21. Technologic Paper No. 176, Slushing oils. 22. Circular No. 97. Recommended specifications for green paint—Semipaste

and ready-mixed.

23. Circular No. 98, Recommended specitication.s for volatile mineral spirits for

thinning paints.

24. Circular No. 102, Recommended specification for composite thinner for

thinning semipaste paints when the use of straight linseed oil is not

justified.

25. Circular No. 103, Recommended s]3ecification for spar varnish.

26. Circular No. 104, Recommended specification for asphalt varnish.

27. Circular No. 105, Recommended specification for liquid paint drier.

28. Determination of cobalt and nickel in cobalt steels, published in .Tour. Ind.

and Eng. Chem., 13, p. 540 ; 1921. The following are in preparation or in press

Equilibria in the system carbon disulphide-methyl alcohol and carbon disulphide-ethyl alcohol.

Preparation of pure ammonia.

Vapor pressure of carbon dioxide.

Density and expansivity of sodium chloride solutions.

Technologic Paper No. 195. Zinc cyan'.de plating solutions.

Determination of aluminum as aluminum pho.sphate.

Quantitative precipitation by ammonia of phosphoru.s jientoxide with aluniiniini

hydroxide.

Determination of molybdenum iu steel. Modified method for the determination of iron and vaiuulium after reduction by

hydrogen sulphide.

Standardization of solutions employed in the evolution method for sulphur.

Notes on the analysis of the Bureau of Standards cast bronze No. 52. Notes on the alkali-molybdate method for phosphorus in irons.

Catalytic .oxidation of petroleum oils. Determination of available quicklime an dhydrated lime.

Circular No, 111, Reconnnended specifications for flat interior lithophone

paint—White and light tints. Determiuation of the ;icid number of tung and "tber vegetable oils.

6. ENGINEERING PHYSICS.

Investigations relating to mechanics, sound, and properties of matter; testing and

development of engineering instruments; performance standards of mechanical appliances;

sound ranging; investigation of soundproofing properties of building materials; analysis

and correction of acoustical defects of assembly rooms; elastic properties of diaphragms

and springs; investigation, testing, and experimental development of aircraft instruments;

ballistics; aerodynamical testing and research. GENERAL.

The Engineering Physics Division includes sections dealing with

(1) engineering instruments and mechanical appliances. (2) sound

investigations, (3) aeronautic instruments, and (4) aeroclynamical

physics. In addition special experimental and tlieoretical researches
160 KEPOKT (W lUKFX'TOK OF BrTMLVU oy STAISTDAKDS.

are carried on b,v a staff of engineering physicists. The activities of

the division in testing and rosea roll are described in the following

pages. A less tangible but e(iually important feature of the work is

to be found in the ad"\'isorY relationship which has been developed

with other technical branches of the Government and with the

industries. This is illustrated by the participation by the Bureau (1)

in the formulation of several of the. power test codes of the American

Society of Mechanical Engineers and in the work of the A. S. M. E.

fluid meters research committee ; (2) in the work of the aerodynamics

committee of the National Advisory Committee for Aeronautics;

and (3) in numerous conferences with representatives of the Army

and Navy, particularly in connection with problems in aerod3aiamics

and ^ballistics.

ENGINEERING INSTRUMENTS.

Current-Meter Rating Station.

The accurate calibration of water current meters used in measuring the discharge of rivers and other open channels requires equipment too extensive and costty to be provided by private enterprise.

A hydraulic laboratory, designed and equipped especially for this

purpose and housed in so as to be available throughout the year, is maintained by the Bureau to supply this necessarj?^ service. "During

the past fiscal year 279 current meters of various types were calibrated for the engineering bureaus of the Government, instrument

manufacturers, and engineers in private practice.

Calibration of Instruments.

During the past fiscal year 511 instruments were tested, including

current meters, pressure gauges of various descriptions, anemometers,

water meters, speedometers, steam-engine indicators, and miscella- neous engineering instrimients.

Hydrogen Cylinder Valves.

At the request of the office of the chief of Air Service of the

Arm}^ experiments were undertaken to secure a more reliable highpressure gas valve for use on hydrogen cylinders. A series of compuj-ative tests under conditions approximating those occurring in

service were made of the A^alve now used and a number of other

types, resulting in the selection of a design which promises to meet

satisfactorilv the requirements, both as regards tightness and durability.

Safety-Release Device for Hydrogen Valves.

The investigation of hydrogen valves has been extended at the

i-equest of the Air Service to include a study of the safety-release

device which forms a part of these valves. The function of this

device is to safeguaixl the cylinder against explosion if dangerous

pressures are developed witliin the cylinder by reason of their being

accidentally exposed to high temperatures. The gradual yielding

of the safety-release device now in use under continued pressure

and its consequent discharge under ordinary service conditions has

occasioned an appreciable loss of gas. Experiments are now in prog1
KBPOKT OF DlEECrOK OF BUEEAU OF STANDAEDS. 161

ress to secure data for the specification of a device which will correct

this condition, if possible, Avithout im2:)ortant changes in the present

equipment.

Radiator Return Line Valves.

The Bureau has in the past few years made numerous i:)erform- ance tests of the automatic valves used at the outlet of radiators in

vacuum-heating systems to remove water of condensation and air

and to prevent the passage of uncondensed steam. These tests have

been made at the request of the Office of the Supervising Architect

of the Treasury' Department for its guidance in approval of equipment of this character for use on projects under its control. Valves

of this type play such an important part in the successful operation of vacuum-heating S3'stems that the Bureau has recently undertaken a series of tests of a number of representative brands collected

in the open market to determine what standard of performance is

attained in the commercial production of these apjjliances and what

performance may reasonably be required. It is proposed to publish

the general results of these tests in the near future.

Air Measurements o£ Vacuum Cleaners.

It is the trade practice to express the performance of vacuum

cleaners in terms of (1) the vacuum developed at the tool and (2)

the volume of air exhausted by the machine in a given time. No

uniform method of making these measurements has been in use, Avith

the result that the values given for these quantities by the different

manufacturers are not comparable. At the request of the Vacuum

Cleaner Manufactiu-ers' Association a standard procedure has been

ilevelojied which will reduce the ratings to a comparable basis.

Fire Extinguishers.

The investigation and testing of fire extinguishers was inaugurated at the Bureau several years ago for the guidance of the Steamboat-Inspection Service in its approval of equipment of this character on vessels under its jurisdiction. Tweh^e such devices, involving in some instances neAV principles of construction and operation, were examined during the year.

Miscellaneous Engineering Tests.

g A number of miscellaneous tests of appliances were made, such as hydrostatic tests of cylinders and other containers, examinations and

tests of air pumps, valves, and similar appliances.

SOUND MEASUREMENTS.

The principal obstacle in the investigation of scientific and industrial problems in sound is the lack of suitable measuring instruments. It has, therefore, been necessary to develop h number of instruments for qiumtitative sound measurement in the sound

laboratory.

Sound Source.

A portable electromechanical sound source has been devised whicli can be used for soimd measurements under most conditions en- countered in i)ractice. It consists of a specially designed electron

C4984—21 n
162 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

tube oscillator, together with an electromechanical output instrument of the loud-speaking telephone type. Practically the entire

audible frequency range is covered by this instrument, and wide

latitude of intensity is aA^ailable. The purity of the sound output

under various conditions has been carefully studied. This instrument has rendered valuable service in connection with sound-reflection measurements.

Intensity Measurements of Sound.

Many of the instruments used in measuring sound intensity at any

frequency, such as the Kaleigh disk or the Webster phonometer, can not readily be changed from one frequency to another over a wide I'ange. An apparatus possessing this desirable feature has

been t'onstructed, the apparatus being a development of that devised

by Prof. G. W. Pierce. A telephone receiver is used as the receiving element, and a crystal detector-galvanometer circuit forms the

essential indicating element. In order to increase the intensity

range of the instrument, two stages of electron-tube amj)lification

have been introduced, one or both of which ma}- be used according to

the requirements of the problem.

The Sound Field of a Parabolic Mirror.

The sound source and intensity measuring devices described ubo\"e

have been used to study the sound field of a large parabolic mirror

used by the United States Army for locating aircraft by sound.

Measurements have been made of the distribution of intensity and

of phase, and data have been obtained which will aid in the efficient

design of parabolic mirrors for various acoustical purposes.

Radiation Detector for Airplanes.

During the war a system of detecting airplanes by their heat

radiation was in process of development. The image of the plane

was focused on a sensitive thermopile by means of a parabolic mirror.

Tiie indicating device first used was a galvanometer of extremely

high sensitivity. The practicability of using such an instrument in

the field was seriously questioned. An indicating system, consisting

of suitable amplifiers and current reversers, was developed in the

sound laboratory hj means of which the heat radiation is indicated

by an audible signal in a telephone. The electromotive force generated in the thermopile is first amplified several thousand times by a direct-current amplifier, then reversed without interruption at suitable frequency and the periodically reversed current amplified by a suitable audio-frequencj' amplifier, to the output of which the telephone is attaclied. Adequate sensitivity is obtained in this way.

Building Acoustics,

A large number of inquiries have been received from proprietors

of buildings, manufacturers of building materials, contractors, and

.architects for information concerning the acoustic aspects of building materials and modes of construction. It has been possible to give

only limited assistance in this matter, as, in many instances, th6 data

required do not appear to be in existence. The volume and character

of these inquiries serve to emphasize the need of a well-considered
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 163

program to develop the necessary information, a program involving

a comparative study of all materials and modes of construction

prevalent in the present-day building industry.

Aside from the development of measuring instruments, little progress was made during the year in the work related to building

acoustics. This kind of work requires laboratory space of special

character. So far space has not been available which satisfies these

requirements, even approximately, but plans have been developed for a system of sound chambers which, while modest in proportion, will

make progress along this line possible. The execution of these plans

is now under way.

The Electron-Tube Drive of Tuning Forks and Other Apparatus.

The electron-tube drive of tuning forks developed last year has

been considerably improved, the electric and magnetic circuits now

used making the operation of the fork simpler and the apparatus

more available for general use. The double-slit method of obtaining

time indices from the tuning fork has been discarded in some cases and a tuned vibrator operated by the current from the plate coil of

a fork has been used to obtain the required time index marks on

films. The technique of the measurement of small-scale time

intervals has been simplified considerably in this manner. During

the year the electron-tube drive was successfully applied to the

maintenance of the vibrations of a Webster phone.

The work done by the sound laboratory in developing the use of

the tuning fork for the measurement of small-scale time intervals

has led to a number of applications to which the stalf of the laboratory has devoted the major portion of its energies during the year

just closed.

Radio Time Recorder.

An instrument for recording radio signals, specifically time signals,

was developed for the Coast and Geodetic Survey. This instrument

is sufficiently rugged and the incidental equipment is sufficiently

light to make it available for field use. It is to be used for the

determination of precise longitude of any field station with reference

to that of a standard time-transmitting station, such as Annapolis.

Radio messages have been recorded with success from European

stations with the use of only a single tube of the receiving type.

The chronographic apparatus is so designed that the lags in the

recording apparatus are minimized, local and radio signals being

recorded by the same pen.

The recorders for the longitude work are designed for long-wave

lengths. A short-wave recorder has been designed for use in connection with ballistic measurements on aircraft bombs.

Solenoid Chronograph.

In cooperation with the technical staff of the Ordnance Department, United States Army, especially with Maj. G. F. Hull-, a chronograph has been developed for the very precise measurement of

projectile speeds over small distances. Magnetized projectiles are

fired through suitably placed coils. The coils are all in series and

are connected to an oscillograph element through a transformer.
164 REPOKT OF DIKECTOE OF BUREAU OF STANDARDS.

During the passage of a shell through a coil a deflection of the

oscillograph element is obtained and the sequence of such deflections

on a moving film, together with a suitable time scale, yields the

time intervals required. Proper coordination between the firing of

the gun and the operation of the chronograph has been provided.

Some preliminary work has been done on securing other than

photographic recording Avith the solenoid coils, but definite results

of this work can not be reported at this time.

Several commercial oscillographs have been designed and recon- structed for use in various research problems at the Army proving

grounds at Aberdeen, Md,

Piezo-Electric Pressure Gauge.

Paralleling the work on the solenoid chronograph, the feasibility

of utilizing the piezo-electric effect for obtaining a graphical record

of the time pressure relation in a discharging gun has been investigated. A method utilizing a ballistic galvanometer as the indicating

instrument has been developed, and preliminary results have been

obtained of explosions in a pressure bomb which indicate that the

method is a promising one. Calibration is effected on a testing machine. If the gauge is properly designed, the quartz, which is the

piezo-electric material used, can be safely subjected to practically the

full pressure in the gun. However, a small reducing factor is provided in the gauge. The gauge is practically free from temperature

errors, a calibration at 100° C. agreeing within the error of measure- ment with that made at room temperature.

Sound Ranging.

The sound laboratory has worked in cooperation with the Signal

Corps and the technical staff, Army Ordnance, on various phases of

sound ranging. For the latter organization the section is engaged

in the development of a sound-ranging equipment on the small-arms

range at the Aberdeen Proving Grounds. The purpose of this installation is to get ballistic data from machine-gun firings by soundranging methods.

String Galvanometer.

In connection with this and other problems the provision of adequate damping of the string galvanometer systems used in artillery

sound ranging during the late war has been investigated. An

improved form of string galvanometer in which the strings are immersed in a suitable damping liquid has been developed as a result

of these experiments.

Osciilograph Element Without Damping Fluid.

When high-speed records are to be obtained, the presence of the

damping fluid in the standard type of oscillograph element involves

a loss of light which makes the securing of good records very diffi- cult. Following up a suggestion made in the Electrical Division of

the Bureau, adequate damping without the use of a damping fluid

has been secured by backing the vibrator with a narrow strip of

aluminum about 2.5 mils thick, applied symmetrically with respect

to the mirror and the vibrator strip. The window of the cell usually
REPORT or DIRECTOR OF BUREAU OF STANDARDS. 165

containing the element can be eliminated in this way, and adequate

eddy current damping is obtained if the aluminum strip is suitably

dimensioned.

AERONAUTIC INSTRUMENTS.

The aeronautic instruments section has been engaged in an extensive program of research and development work on aircraft instruments in cooperation with the Army, the Navy, the National Advisory

Committee for Aeronautics, and to a more limited extent with other

Government agencies and private concerns. Besides experimental

investigations and the development of neAV instruments a considerable amount of routine Avork on instruments submitted for tests has

also been carried out.

The development work may be considered under two heads; first,

the experimental investigations, which deal with the fundamental

physical principles involved in instrument design, and second, the

practical design and construction of new types of aircraft instruments.

Altitude Effect on Air-Speed Indicators.

An investigation of the altitude effect on air-speed indicators has

been completed and the results have been published in a report b}^

the National Advisory Committee for Aeronautics. This investigation shows that Venturi tubes when used as air-speed pressure

nozzles deviate considerably at low-air speeds and low-air densities

from the pV- law which is usually assumed throughout the range

of aircraft speeds. Attention was called to this effect in last year's

report, but at that time, owing to limited experimental facilities,

onlj' qualitative data were available. During the past year a wind

tunnel with a IG-incIi throat has been constructed and mounted in

one of the Bureau of Standards altitude chambers. Air speeds up to

approximately 100 miles per hour were attained in this tunnel under

conditions of pressure and temperature corresponding to any desired

altitude up to 30,000 feet, and the following nozzles were examined

United States Navy, United States Army, and Toussaint-Lepere

Pitot-Venturi nozzles, Badin single and double Venturi nozzles, and

the Bruhn double Venturi nozzle. Tables and charts of the altitude

correction for these nozzles to supersede the former corrections which

involve air density alone are in preparation.

Diaphragm Investigation,

Eesearch in connection with the improvement of instrument diaphrams has been continued along the following lines: («) The laws

of deflection for corrugated metallic diaphragms have been determined experimentally. The results will facilitate the work of designinf^ suitable diaphragms to conform to specific conditions of use. (h) IVIeans of computing the effective force of diaphragms—that is. the force available for performing useful work—have l)een developed

for both sylphon diaphragms and slack diaphragms. From the geometrical shape of the diaphragm and the magnitude of the fluid pres- sure the designer can immediately jiredict the effective f(n-ce for any

deflection, (c) Temperature and porosity tests have been carried
166 KEPOKT OF DIRECTOR OF BUREAU OF STANDARDS.

out on a number of rubberized fabrics, doped fabrics, and thin

leathers to determine their suitability for use as slack diaphragms.

Hysteresis in Bourdon Tubes.

Tests for elastic lag and hysteresis have been made on Bourdon

tubes. These tests were made over a pressure range of from to 80

pounds per square inch and a temperature range from to 50° C.

The I'esults as indicated by the limited number of tubes tested show

that the elastic lag and hysteresis of Bourdon tubes is approximately

the same in amount as that found in aneroid diaphragms.

Bimetallic Bars.

Tests have been carried out on flat and coiled bimetallic bars to

determine the character of the deflection with change of temperature

and also to stiid.v the elastic lag and hj^steresis. The deflections were

found to be linear over a range of temperature of from +25° C. to —40° C, and the hysteresis and temperature lag effects were small.

Such bars are capable of developing sufficient force to operate the

temperature-compensating mechanism in aeronautic instruments.

Aircraft Sextants.

In connection with the development of an improved type of aircraft sextant extended tests of available types have been carried out.

Attention has been particularly directed to a study of the optical

systems and to accuracy and convenience in use. Methods of obtaining an artificial horizon have been iuA^estigated to determine the best

form for aircraft sextants.

Aircraft Compasses.

An extensive study of all available types of aircraft compasses

and of the literature on the subject has been made in connection with

the development of a new type of compass. An extended investigation of the Bamberg distant reading compass was made both in the

laborator}' and in flight.

Turn Indicators,

An investigation of aircraft turn indicators has been recently imdertaken at the request of the Army. A survey of existing instruments has been made, and laboratory and flight tests have been con- ducted on available types of turn indicators with a view to the development of a new instrument.

Precision Barometer.

An improved model of precision barometer has been developed and

the laboratory tests indicate a satisfactory performance. The design

is based on the same principle used in the earlier model, namelj', that

of using a relatively flexible diaphragm in conjunction with a stiff

sjDring carefully selected as to its elastic qualities. The spring was

heat treated by the Metallurgical Division of the Bureau. The

pointer of the instrument makes two and one-half revolutions over

the dial. To avoid confusion in reading the instrument, an automatic

dial-shifting device has been devised to change the dial numbers

when the pointer makes more than one complete revolution.
REPORT OF DIRECTOR OF BUREAU OF STAI^DARDS. 167

Temperature Compensated Altimeter.

This instrument consists of a Bureau of Standards precision altimeter combined with a temperature compensating element. Variation of altitude reading with change in the temperature of the atmosphere is automatically corrected on the assumption that the average

temperature of the air column from the ground to the instrument

is equal to the arithmetic mean of the temperatures at the ground

and at the position occupied by the instrument.

Precision Barograph.

A precision barograph incorporating a sylphon diaphragm and

a specially heat-treated coiled internal spring is now uncler construction. This instrument will have a novel recording device which

permits the use of a chart with rectilinear coordinates instead of the

curved time scale. ordinarily used.

Rate-of-Climb Indicator, Model No. 3. Ten instruments of this type have been designed and constructed

xmder the supervision of the Bureau for the use of the Army.

Recording Rate-of-Climb Indicator.

In airplane performance tests it is often desirable to have a permanent record of the rate of climb. Recording apparatus of this

type has been designed and constructed for the Navy. The instrument consists of a rate-of-climb indicator of the capillary leak type

with S3'-lphon diaphragm. A record of the deflections of the diaphragm is obtained by reflecting light from a small mirror onto a

light-sensitive chart attached to a revolving drum.

Combined Statoscope and Rate-of-Climb Indicator.

The purpose of this instrument, which consists essentially of a Bureau of Standards rate-of-climb indicator model No. 3 combined

with a bubble statoscope, is to provide in the same instrument a

j sensitive detector of slight changes of level and a less sensitive quani titative indicator of rates of ascent or descent. By turning a thumbscrew in the case of the instrument it can be used either as a statoscope or as a rate-of-climb indicator. This instrument has been

completed and delivered to the Army.

Ground- Speed Indicator.

At the request of the Balloon and Airship Division of the Army

a ground-speed indicator for free balloons of the three-point sight

type was designed and constructed for use in the recent official

balloon race at Birmingham, Ala.

A ground-speed indicator of the optical synchronizing type has

been designed and practically completed. This instrument consists

essentially of a hexagonal glass prism which is rotated about an

axis perpendicular to the direction of motion of the aircraft relative to the ground. The rate of rotation of the prism required to

make objects on the ground appear to remain at rest is a measure

of the ground speed if the altitude is known. The instrument is so designed as to read directly the ground speed in miles per hour by

means of a tachometer attached to the rotating prism. Altitude
168 EEPOBT OF DIRECTOR OF BUREAU OF STANDARDS.

adjustment is provided so that the instrument can be set to read

correctly at any altitude.

Sextants.

Designs for a new type of aircraft sextant have been prepared and

submitted to the Army. This device differs radically in form from

the marine sextant. A bubble horizon is attached, and a single

rotating mirror is provided. This mirror is turned hy a worm and

wheel suitably graduated, thereby eliminating the large sextant

scale ordinarily used. A method of varying the size of the bubble

to compensate for temperature changes has been incorporated. Electrical illumination of the bubble and scales is provided.

Astronomical Position Finder.

It has been proposed to determine the position of aircraft at night

from any two known celestial objects, such as two stars and the

Greenwich sidereal time. An experimental model of an optical instrument of this type is now under consideration. This instrument

provides a means for determining the altitude of the pole and the

hour angle of the two celestial objects chosen and consists essentially

of a telescope and two mirrors rotatable so as to reflect the light of

the two objects chosen into the telescope. The mirrors are each independentty rotatable about the axis of the telescope and about an

axis at right angles to the telescojie. A bubble horizon is used.

Horizontal Angle Indicator.

An instrument for measuring horizontal angles from captive balloons was submitted by the Balloon and Airship Division of the

Army for test and investigation. Several changes were made which

simplified the instrument and increased its range. The various optical methods which may be used in an instrument of this t^^pe have

been studied and a second model embodying the most promising optical combination has been designed.

Tachometers.

The results of tests on an experimental model of a centrifugal

tachometer of the double-inclined weight type have been incorporated in the design of a new instrument. A circular spring type of

centrifugal tachometer, extremely simple and with few moving parts,

has been tested and found to give promising results. An instrument

of this type is being designed.

Air-Speed Indicator for Dirigibles.

The development of an air-speed indicator having a range of from

10 to 80 miles per hour for use on dirigible balloons has been imdertaken and a model instrument completed. After a study of the possibilities of the ordinary differential pressure type of air-speed indicator, the pressure-plate type, anemometer type, and hot-wire type,

the cup anemometer was selected as the most suitable for the conditions. It was necessary to employ some means of transferring the

motion of the anemometer to the instrument board without putting

an appreciable load on the anemometer. This was done by attaching

to the anemometer a specially constructed commutator which auto-
KEPOKT OF DIRECTOR OF BUREAU OF STANDARDS. 169

matically charges a condenser and discharges it through a sensitive

galvanometer at rapid interval's proportional to the rate of revolution of the anemometer. The effective current and consequently

the deflection of the galvanometer is proportional to the speed of the

anemometer.

Ballonet Volume Indicator for Dirigibles.

The purpose of this instrument is to indicate the volume of air

contained in the ballonets of nonrigid dirigible balloons. Actual

tests carried on 'inside the ballonet of a nonrigid airship at Langley

Field showed that the mechanical type of indicator which had

already been tried was less promising than an instrument depending upon the static pressure of the air in the ballonet. The design of

a volume indicator of the latter type is now in preparation.

Compasses.

Results of the investigation of compasses have been applied in the

design of a new type of double-pivot liquid-damped compass. A

model of the instrument has been nearly completed.

Standard Testing Sets for Field Use.

At the request of the Navy standard sets of aeronautic instruments have been made for field use in the comparison and calibration

of service instruments. Tliese sets consist of high and low range

altimeters, air-speed indicators, and thermometers, a tachometer,

clock, and record pad. Selected instruments were carefvdly calibrated for these sets. Carrying cases are to be provided.

Foreign Representative.

Pursuant of the policy of following the latest developments in

aeronautic instruments in foreign countries a member of the sec- tion has been detailed abroad during the last three months of the

year. Special attention was given to lighter-tlian-air craft instrument development in England, France, Italy, and Germany-. This

work has been carried on in cooperation with our military, naval,

and commercial attaches. Much valuable information has in this

manner been placed at our disposal, and in reciprocation information in regard to recent investigations at the Bureau of Standards

j has been made available to foreign officials interested in aeronautic

' instrument development.

Instrument Collection.

Further additions have been made during the year to the collection of aeronautic instruments which is maintained by -the Bureau of Standards. Sixty-fi\e new instruments ha^'e been acquired

l)y purchase abroad, from local manufacturers, and by loan from

other departments of tlie Government. These include electric and

air-driven gyroturn indicators, ordinary and distant reading compasses, chronometric. centrifugal, and electric tachometers, liquid

oxygen apparatus, air-s])eed indicators, air-distance indicators, stat- oscopes, barographs and thermographs, gasoline flow meters, accelerometers, electric thermometers, gasoline level gauges, and ])ressure

gauges.
170 REPORT OF DIRECTOR OF BI^REAU OF STANDARD^

Routine Testing.

While the major purt of the work of the aeronautic instruments

section during the pnst year lias been deA oted to the development of

new types of instruments, u considerable amount of routine testing

has been done for difl'erent departments of the Government and

private concerns. This includes 62 aneroid barometers. 3 siirveying

aneroids, 1 pocket aneroid, 3 mercurial barometers, 2 high-altitude

barographs, 1 weather barograph, 3 thermographs, 1 hydrograph,

13 air-speed indicators, 26 tachometers. 6 gyro turn indicators, 4 sextants, 1 horizontal angle indicator, 2 balloon manonreters, 1 gaspressure manometer, 4 inclinometers, 18 instrument-board thei-mometers, 16 strut thermometers. 43 sphygmonianometors, 1 airship slide

rule. 2 propeller pumps.

Flight Tests on Aeronautic Instruments.

The successful development of new types of aeronautic instruments requires that they be tested in flight in the course of development. This need has been fulfilled through the courtesy of the

^Vrmy and Navy, who have arranged to place at the disposal of the

Bureau aircraft for the testing of the instruuients which have been

under develojjment. Eighteen flights have been made in airplanes,

seaplanes, and dirigibles, and experiments have also been carried out

in captive balloons.

AERODYNAMICAL PHYSICS.

Two wind tunnels are now available at the Bureau for aerodynamical work and a third is under construction. The tunnels differ

in size and speed range and are adapted to a great variety of work.

The 54-inch tunnel, located in the wdnd tunnel building, is of the

N. P. L. tj'pe, octagonal in cross section, the 54-inch dimension being

between opposite faces. The faired entrance of the tunnel is about

4 feet long, the parallel portion 25 feet long, and the exhaust cone

15 feetf long. The diameter at the propeller end is 9 feet. The

tunnel room is 68.4 feet long, 28.6 feet wide, and 18 feet high. The

room is divided transversely near the exit end of the tunnel by a wall honeycomb, consisting of pasteboard tubes 1.5 inches in diameter

and 4 inches long, packed in a light framework, which is covered

on both sides by mosquito bar. This open honeycomb structiire serves to damp out the swirl and eddies in the air stream as it returns

from the fan to the tunnel entrance. A speed range of 17 to 90

miles per hour is attained in the tunnel with the expenditure of from

2 to 90 horsepower. Two balances are available, the first being a modified N. P. L. balance wdth an auxiliary balance for pitching

moments, used chiefly for work on aerofoils and airplane models.

The second balance is designed for very heavj^ models, such as radiator sections, engine cylinders, etc., and is adapted chiefly to

head-resistance measurements. For very accurate work at low speeds

storage-battery current may be used.

The 36-inch tunnel, located in the northwest building of the

Bureau, is of the Venturi type, circular in cross section. The en- trance cone is 12 feet long, the working portion 6 feet long, and the

exit cone 33 feet long. The diameter at the end of the exit cone and

|

the front of the entrance cone is 7 feet. The timnel room is 10617
REPORT OF DIRECTOR OE BUREAU OE STANDARDS. 171

long, 25.2 feet wide, and 10.2 feet high. Two wall honeycombs,

consisting of hollow tile covered with mosquito bar, extend entirely across the room in the path of the returning air stream. A speed

range of 11 to 180 miles per hour maj' be attained in this tunnel with

an expenditure of from 1 to 110 horsepower. Speeds over 150 miles

per hour may be maintained for short intervals of time only. This

tunnel is steady and I'elatively free from turbulence. A balance of a modified N. P. L. type is under construction, but deflection methods

have been much used in the past. The tunnel is well suited to the

calibration of airplane instriunents at airplane speeds and to the

investigation of devices functioning in a wind stream of high speed.

The third tunnel, which is now under construction, will be 10

feet in diameter and will not be housed. A speed range equal to

that of the 51:-inc]i tunnel is expected, with an expenditure of 250

horsepower. The tunnel, circular in section, will consist of a straight

part 50 feet long and an exit cone 34 feet long, 1-1 feet in diameter,

at the propeller end.

Apparatus is thus available for practically all kinds of aero- dynamic testing except propeller and windmill torque and thrust

measurements.

Aerodynamical Characteristics of Aircraft Bombs.

The aerodynamical physics section has been working for the past

two years in close cooperation with the Aircraft Armament Division

of the Ordnance Department, United States Army, on j)roblems con- nected Avith aerial bombing. During the first part of the year a re- port was prepared in which the results of all previous wind-tunnel

tests on boml) models wore analyzed and compared. As a result of

this study, and in view of the limited number of forms included, the

Ordnance Department felt that a comprehensive investigation of a large number of bomb forms should be undertaken.

The general investigation is now well under vfuj. The Ordnance

Department furnished an exceptionally good collection of aluminum

models of ogives and bodies from which a large number of bomb

forms could be built up. A convenient and accurate deflection method

of measuring head resistance was developed by the wind-tunnel staff,

and a new oscillating apparatus was designed and constructed. A

large number of tests have been conducted, the results of which give

a new conception of the i-elative importance of the various elements

of bomb design.

The Bureau has also cooperated with the Ordnance Department in

te,sts at the Aberdeen Proving Ground on service bombs dropped

from an airplane. The method used, which was devised by Maj. F.

C Brown, requires a series of photographs of the falling bomb over

a body of Avater, which are taken from the airplane with the aid of a

special moving-picture camera. A vertical reference line through the

airplane is determined by the position on the film of the image of the

)-eflection of the airplane on the body of water. Landmarks are an- chored on the water at known distances apart, the images of which

on the film serve to determine the measurement of ground speed and

the height. The camera points down fi'om the airplane and is focused

for distant objects. On a part of the film there is focused, hy means

of a camera lens and a mirror, the image of a stop watch. The camera
172 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

is located a little to one side of the center of gravity of the bomb, so that the film shows the airplane reflection, the landmarks, the bomb,

and the watch. The work of the Bureau in connection with these

tests consisted in the measurement and interpretation of the films

obtained.

Suitable reflections have been difficult to secure, and the Bureau has

assisted the Ordnance Department in the planning of a supplementary method in which cameras obscura are used. Two cameras are to

be employed. One points vertically upward, and the other, located at the end of a measured base line, points at a vertical angle toward the

first. The bomb is to be released over the vertical camera, its position

on the plotting boards being dotted in for some seconds just prior to

the release. The time of fall of the bomb is to be measured by a special chronograph, the signal at release being given by wireless. The

Bureau is constructing a special receiving set and other minor equipment necessary for this work.

Investigation of Flow Around Wind Screens.

In cooperation with the Balloon and Airship Division of the Air

Service an investigation is being made of the flow aroimd the wind

screens which are used for the protection of dirigibles when entering

and leaving their hangars in cross winds. A solid screen is objectionable for this purpose on account of the violent eddying motion produced on its lee side. The problem is to design a screen which will

give the greatest reduction in the wind speed with the least eddying.

Wind-tunnel tests have been carried out on various types of perforated screens, on the basis of which a recommendation has been

made to the Balloon and Airship Division for screens for immediate

use. The wind-tunnel work is now being supplemented by outdoor

measurements of the forces on a one-twentieth scale model of a standard type dirigible when located near the entrance to its hangar and

protected by various types of screens.

Resistance of Spherical Bodies.

Further measurements have been made of the air resistance of

spherical bodies of various tj'^pes. The importance of such measure- ments lies in the fact that the flow about spheres is very sensitive to

conditions of turbulence in the air stream. Hence, the turbulence

which has an appreciable effect on the air resistance of cylinders,

spheres, thick wing sections, etc., may be qualitatively studied by

studying the resistance of spheres under various conditions.

Through a certain range in air speed the effect of turbulence is to

jj

reduce the air resistance of a sphere. Fiu'thermore, turbulence may

be produced simply by roughening the surface of the sphere. Incidentally, these facts find an interesting application to golf balls.

Wind-tunnel measurements show that the roughened ball has less

lieacl resistance than a smooth ball for speeds corresponding to those

prevailing during the flight of a swiftl^^ driA'en ball, so that it shoidd

be Dossibie to drive a ball with a roughened surface farthei' and faster

tlian a smooth ball of the same size and weight.

Pilot balloons are used to explore the air currents in the upper

regions of the atmosphere. It is of importance to know their head

resistance. The results of wind-tunnel tests show a general agree-
REPORT OF DIRECTOIl 01-' BUREAU OF STANDARDS. 173

ment of the coefficients with those obtained for smooth spheres.

However, the results do not check numerically with those calculated

from the observed rate of ascent of the balloon in the open air. The

discrepancy is a comparatively large one, and no explanation has as yet been found. In general, the effects of turbulence are of primary

concern in the interpretation of wind-tunnel data, and any failure

in the application of Avind-tunnel results to free-air conditions should

be thoroughly investigated.

Ventilation Problems.

Toward the end of last year the Bureau undertook, at the suggestion of the American Society of Heating and v entilating Engineers,

the investigation of roof ventilators. This investigation Avas carried

out in the laboratory where conditions were under control, and, although all conditions of practice were not typified by the installation,

comparative results were obtained. The results of the investigation

were presented liefore the societj^ at their annual meeting and

aroused considerable interest. The Bureau plans to issue a technologic paper on the subject.

Testing of Instruments and Airplane Models.

The usual routine testing of airfoils, airplane models, anemometers,

and other instruments has required a part of the time of the windtunnel staff. The tunnels were also used in developmental work in

cooperation with the aeronautic instruments section and a study was

made, in cooperation with the engineering instruments section, of

the swirl correction of the whirling arm used for anemometer test- ing and of the interference effects of various anemometer mountings.

PUBLICATIONS.

The following papers from the Division of Engineering Physics

have been published during the year

Notes 111 sniall-tlow meters for air CE. P'nck iifiliani) . Teeh. I'aper No. ISB. On the use of models in investisatinp: tlie res-Stance of ship structures to ex- ternal exjilosions (E. Buckingham), .lour, of the Am. Soc. of Naval Engs.,

May, 1921.

Notes on the use of (limciisional reasonin.a; (E. Euckiugham )

, Phil. Mag., 1921. Some comparative tests of 16-iiich roof ventilators (H. L. Dr.vden, AV. F. Stutz,

and R. H. Heald), Jour. Am. Soc. of Heat, and Vent. Eng.. March, 1921.

The altitude effect on air-si^eed indicators (M. D. Hersey, F. L. Hunt, and H. N. Eaton). Rep. No. 110. National Advisory Committee for Aeronautics, 1921. Sphygmomanometers (.T. Ij. AA'ilson and H. N. Eaton), B. of S. fir. (mimeographed )

The following papers ha^e been accepted by the National Advisory Committee for Aeronautics for publication in their annual

report for 1921

Cencral classification of instruments and problems (M. D. Hersey).

.\lt:>uieters and barographs (A. H. Mears, H. B. Henrickson, and W. G. Brombacher).

Precision altimeter design (.T. B. Peterson and J. R. Freeman, .ir.). Sbitoscojies and rate-of-clinib indicators (A. H. Meai-s).

.\erograj)hic instruments (J. A. C. Warner).

Air-speed indicators (F. L. Hunt).

'I'esting methods for air-speed indicators (H. O. Stearns).

Principles of .ground-speed measurement (F. L. Hunt).
174 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Inclinometers and banking indicators (AV. S. Franklin and M. H. StiUman)

A new form of gyrostal)ilizers (W. S. Franklin).

Aircraft compasses and turn indicators (J. A. C. Warner).

Testing of magnetic compasses (R. L. Sanford).^

Aircraft tachometers (G. E. Waslibiirn).

Testing methods for tachometers (II. C. Sylvander).

Thermometers for aircraft engines (E. F. Mueller and K. M. Wilhelm).^

Air-pressure and oil-pressnre gages (H. N. Eaton).

Gasoline-depth gages and flow meters (J. A. C. Warner).

Oxygen instruments (F. L. Hunt).

Navigating instruments (H. N. Eaton).

Recent developments in aeronautic instruments (F. L. Hunt).

The following papers have been presented before technical and

scientific societies

A portable sound producer of considerable range as to frequency, and in- tensity (E. A. Eckhardt), Am. Phys. Soc, December, 1920. The sound field of a parabolic mirror (E. A. Eckhardt), Am. Phys. Soc,

December. 192Q.

Apparatus for measuring scmnd intensity (.7. C. Karcher), Am. Phys. Soc.

December, 1920.

A method of measuring phase differences in a sound field (.7. C. Karcher), Am.

Phys. Soc, December, 1920.

Some comparative tests of 16-inch roof ventilators (H. L. Dryden, W. F. Stutz, and R. H. Heald), Am. Soc. of Heat, and Vent. Engs., January,

1921.

Wind tunnels and their uses (L. .7. Briggs), Washington section of Am Soc. of Mecli. Engs., January, 1921.

Measurement of air resistance on projectiles in actual flight (E. A. Eckhardt),

^Vashington section Am. Soc of Mech. Engs., January, 1921. Electron-tube drive for tuning forks (E. A. Eckhardt, J. C. Karclier, and M.

Keiser), Am. Phys. Soc. February, 1921.

A high-speed oscillograph camera (E. A. Eckliardt). Am. Phys. Soc. Fehruarv.

1921.

A chronographic recorder of radio time signals (E. A. Eckhardt and J. C. Karclier), Tlie Philosopliical Society of Washinglon, March, 1921; Au). Phys,

Soc. April, 1921. The determination of instantaneous pressures in guns by means of a piezoelectric gage and a ballistic galvanometer (J. C. Karcber), Auv. Phys. Soc,

April, 1921.

7. STRUCTURAL, ENGINEERING, AND MISCELLANEOUS

MATERIALS.

This division is concerned with the investigation of the properties, uses, design, and

fabrication of structural, engineering, and miscellaneous materials. This includes metal

of all kinds and wood, especially when fabricated into structures or structural parts, cement, concrete, lime, gypsum, sand, stone, and sand-lime brick. Under miscellaneous

materials are included leather, rubber, and composition materials used in place of these,

textiles, paper, and lubricating oils. To make the study of these products complete, it

is desirable to take into consideration the processes by which they are manufactured. Hence, the equipment includes an experimental rubber mill, textile mill, paper machine, cement plant, etc. The division is also concerned in the improvement of tiie present and

the developing of new methods of testing and the development of standards covering

the use of the materials concerned. PHYSICAL TESTS OF STRUCTURAL MATERIALS.

General Scope of Work.

During the recent war many tests of materials and equipment were

made as quickly as possible to assist the military service in placing

contracts. Often these were of such a nature that they were of permanent technical value. At present these laboratories are making

' Contribution from tlie Electrical Division.

* Coiitiihulion from tho ITpat Division.
i ..^^^ REPORT OF DIRECTOR OE BUREAU OF STANDARDS. 175

similar tests for the military and other branches of the Government,

, ^but the munber has greatly decreased. Opportunity is therefore preI P^sented to carry on work of a cliaracter which will be of value to

j engineers and othei"s engaged in technical and industrial lines. The

I equipment of these laboratories, some of which is being moved from

j its original location to newer and more suitable quarters, will be put

in the best possible condition for efficient operation.

Some of the problems now receiving attention are very important

ones. Among these may be mentioned the calibration of testing maI chines, for which there is a constant demand from the owners of such

machines in this country, and the testing of aircraft materials.

The Emery hydraulic testing machines will be moved to the new

I quarters as soon as practicable. This will interrupt the work someI what during the coming year. The investigation of the strength of

j aircraft parts for the Navy, which will require several months to

complete, should be finished before this equipment is dismantled.

II By that time it is believed that everything will be ready in the new

I location. The use of a room adjacent to the middle wing of the in-

( dustrial building, having excellent light, Avill be very beneficial. All

' the laboratories of this section will then be so grouped that the equipment can be efficiently used and can be given proper supervision.

Much still remains to be done before these laboratories are in satisI factory condition, but progress will be made.

I Tests of Large H Columns.

' The results of the tests of large columns made for the American'

Society of Civil Engineers showed a systematic difference between

the strength of columns made of thin and thick rolled material. The

present series of tests were made to study this elTect in columns of

still larger cross-section. Thirty-nine columns having cross-sections

of five different types, (1) light and (2) heavy built-up plate and

angle sections, (3) light built-up channel sections, (4) light and (5)

lieavy solid rolled sections, were tested in the l(),000,000-pound testingmachine of the Bureau of Standards at Pittsburgh. The cross-sec- tional areas were approximately 40 square inches for the light and 86

square inches for the heavj^ sections, and the lengths were 12, 18, and

24 feet.

Physical tests and chemical analyses were made on coupons cut

from the columns and the results compared with those from tests of

the complete columns. The following summarizes the results of the

tests

1. The columns were carefully prepared, their ends were accurately

surfaced, and they were carefully centered in the testing machine.

This is shown by the uniformity of the stress-strain curves and by the

steepness and sudden brealv in the lateral deflection curves.

2. The differences in the observed average column strength of these

columns is almost wholly due to differences in the yield point of the

material of which they were constructed.

3. Lack of homogeneity of the material may account in part for

the low efficiencies of tlie heavy-rolled sections.

4. Secondary failure did not occur excejit, possibly, to a slight ex- tent in the channel section. This shows that the webs were amply

strong enough.to carry the shear and the flanges thick enough to prevent buckling.
176 REPORT OP DIRECTOK OF BUREAU OF STANDARDS.

5. A small increase in econoni}- in the use of the steel might be

obtained by increasing the radius of gyration of the sections.

6. In view of the controlling influence of the yield point of the

naaterial upon the column strength, a more precise standard of definition and measurement of yield point is needed.

7. A properly standardized ^ drop of beam " yield point will furnish a measure of the strength of column material provided the material is sufficiently homogeneous, but a different measure will be

obtained from' the " useful limit point or other extensometer measurements.

8. The yield points determined in commercial mill tests apparently bear no relation to the column strength.

9. Heavy-rolled material bought under the same material spe-;ifications (American Society for Testing Materials) will s]iov»- a lower

column strength than light-rolled material, because of a lower yield

point.

10. Increase in the ultimate strength of steel, due to increased

carbon content, apparently does not increase the yield point as greatly

as a corresponding increase due to working

Strain-Gauge Measurements on Welded and Riveted Tanks.

To determine the value of welding for sheet-steel pipe lines, instead of the iisual riveted construction, four tanks 10 feet long and

1 feet in diameter, made from y'V-inch plate, were tested under internal hydraulic pressure. One had riveted, one lapwelded, and two

butt-welded seams. Tlie welds were made with electric arc welding

machines.

Strain-gauge measui-ements were made longitudinalW, transversely, and diagonally on tlie cylindrical surface of the tanks, both

across seams and on the unjoined plate. Measurements were also

taken on the shell adjacent to tlie ends and also on the end. To determine the efl'ect of the manhole, measurements Avere made aromid

this opening in the shell on one of the tanks.

Strain-gauge readings were taken for eacli 50 pounds per square

inch increment of pressure, and at 300 pounds ])er scjuare inch an

impact test of the seams was made with a sledge and the readings

continued for increments of 100 pounds per square inch imtil fail- ure occurred. The observed strains were compared with the theoretical strains. Due to the large number of observations it was

found convenient to sIioaa' the experimental results graphically. . It

was found that the accepted theory for the design of tanks is suffi- ciently accui'.ate if the stresses are not increased by secondary stresses. The strains computed by the conmion theory for thin cylinders

agree well with the more exact tlieory and with the measure of

strains, i)rovided the latter are not affected by secondary causes. Due to the fact that the shells of the tanks were not accurately cylindrical, great changes in the strain intensity were caused by secondary

stresses. The tanks fell into two groups. One butt-welded tank and the

riveted tank failed at about the same working ])ressiire. 200 pounds

per square inch, due probably to poor welding in the case of the

welded tank. The other butt-welded and lajjwelded tank withstood

at least twice this pressure. In all cases the tanks failed by leaking
REPORT OF DIREC!T()R OF BUREAU OF STAI^DARDS. 177

so rapicUy at the seams that it was impossible to maintain the pressure.

•

Permissible Working Stresses in Steel Buildings.

At the request of the Building Code Committee of the Bureau an

investigation of the permissible stresses in steel buildings was undertaken. When the steelwork for the new annex to the Hotel Statler

in Buffalo was redesigned a stress of 18,000 wa^ ::sed instead of

1G,000 pounds per square inch, as required by the Buffalo building

code. Special permission was obtained for this increase in stress. If this was practicable for other buildings, the cost of construction

could be reduced. This, in turn, would stimulate building construction and help to relieve the present crisis.

A preliminar}^ survey of the subject indicates that little is to be

gained from tests of structural steel as made at present. Steel having a higher strength, ])erhaps obtained by heat treatment, can be

used, but the cost would probably be great, and the inspection and

testing would have to be conducted Avith great care. For buildings

subjected onh^ to static loading or, in other words, to a constant load

which remains in place for long periods of time, comparatively high

stresses can be used. Great care miist, however, be exercised to design the building for the loads which will actually occur. If the designed load is greater than the actual load, a condition which often

occurs, a waste of material results. If, on the other hand, a greater

load is used, costly failures are probable.

A summary of the stresses permitted by the building codes in this'

country is included in this report, and also references to articles in

which different phases of the question are considered. An outline of

the investigations which should be made before any change in the

present permissible stresses is reconunended is included. This whole

subject is one which should receive careful consideration, as very

important interests are involved. It seems probable that the construction of many types of building could be cheajDened without

serious disadvantages, but the amount of saving can only be estimated after a thorougli survey of the possibilities.

Strain-Gauge Test Under Load of the Arlington Building.

This reinforced concrete building occupied by the Bureau of War

Risk Insurance has a floor system of terra-cotta tile and reinforced

conci'ete, upon which few tests have been made. At the request of

the Treasury Department portions of the floor system of this building were sand loaded and the resulting deformation of the structure

measured with a strain gauge. These data are being prepared for

publication. A great deal of work was involved in analj'^zing the

results and preparing the drawings for reproduction.

Investigation of the Strength of Hollow Brick Walls.

To economize in material and so lower the cost of building conbtruction, walls have been designed using the usual size of brick but

arranging them so as to leave air spaces in the wall. Walls of this

type are being tested under concentric load to determine their

strength. Thev are 6 feet wide, 9 feet high, and both 8 and 12

inches thick. "For comparison solid brick walls of the usual con- 649S4—21 12
178 REPOBT OF DIRECTOR OF BUREAU OF STANDARDS.

struction of tlie same size are made and tested. As the load in a building is not uniformly distributed over the section of the wall, it is planned to load Avails in the future over half their thickness only

to approximate actual conditions. Although these tests are not complete, some interesting results have been obtained, and it is believed

that information will be secured which will be of considerable interest and value.

Investigation of the Fatigue Resistance of Sheet Metal.

At the request of the Navy Department, and in cooperation with

the National Advisory Committee for Aeronautics, the fatigue resist- ance of sheet metals is being determined. The metals to be used are those suitable for aircraft construction, particularly those having

light weight, such as duralumin. The thicknesses will vary from

0.02 to 0.10 inch.

Two testing machines of unique design have been made and found

to give satisfactory results upon the thinner sheets. Drawings have

been prepared for both the flexural and the impact fatigue machines,

and several of eacli are noAV being constructed. In addition to the

fatigue tests, tensile, bend, and other tests Avill be made to find the

other properties of each material. These fatigue tests are of great

importance, as experience seems to show that many of the light

alloys, including those containing aluminum, often fail from fatigue.

As many of these materials have not been used for a sufficient time to

determine their suitability for aircraft construction, laboratory tests are especially important to prevent the use of unsuitable material,

with disastrous accidents and possibly great loss of life.

Investigation of the Impact Resistance of Sheet Metal.

At the request of the Air Service of the Army the resistance of

sheet metal to impact is being studied. The materials are those

suitable for aircraft, and a wide variety of both ferrous and nonferrous alloys are to be included. The ability to absorb a large

amount of energy or work may prove to be a very important quality

in metals used for aircraft. For materials having equal strengths

it is believed that a great difference in impact resistance will be

found. As no apparatus suitable for this work was available, an

Izod and a Charpy impact machine were modified to test sheet-metal

specimens by tensile loading. The results with the Izod machine

proved to be consistent, and it will be used for the test program.

The materials will all be tested in tension, bending, etc., as well as in | j impact.

Investigation of Body-Bound Bolts.

An investigation was made of liquid air and an explosive charge

for body-bound bolts. The experiments were conducted at the re- quest of the Bureau of Construction and Repair, Navy Department,

in order to determine the force required to cause slipping of a bodybound bolt.

Two methods of obtaining a tight fit between a bolt and the

material surrounding it were used in an effort to find one which

could be used for attaching the lugs of turret guns to the deck. The

bolts used for this purpose are subjected to great shearing stresses
EEPOKT OF DIRECTOR OF BUREAU OF STANDARDS. 179

when the guns are fired. At the present time the Navy uses taper

bolts, which are drawn tightly into taper holes.

The tests were made on bolts which had been body, bound by the

following methods: (1) Liquid air, shrinking the bolt by immersing

in liquid air and allowing it to expand in the hole; (2) explosive,

inserting the bolt, which was a loose fit in the hole, and expanding it by an explosive charge placed in a small hole in the axis of the bolt.

Experiments liad previously been made on cylindrical pins which

were from 0.001 to 0.0015 inch larger than the holes, and which were

contracted by immersing in liquid air to fit the holes. Tests were

also made on taper pins, which were contracted by immersing in

liquid air and then driven into tapered holes.

The results of the investigation on the use of liquid air showed

that a tighter fit can be obtained with taper pins than with a cylindrical pin. The average unit frictional resistance as shown by the

tests on cylindrical pins was 2,150 pounds per square inch, while the

average value for the taper pins was 3,000 pounds per square inch.

The test of the bolts expanded by explosive charges showed that

satisfactory results can be obtained by this method. The average

unit frictional resistance was 2,180 pounds per square inch. The

tightness of the fit is dependent upon the size of the hole bored in

the axis of the bolt to contain the powder charge, as well as upon the

pressure of the explosion.

Investigation of the Strength of Screw Threads for the National

Screw Thread Commission.

The data have been compiled and the report completed on the

investigation of the strength of screw threads for the National Screw

Thread Commission. In this investigation tests were made to determine the effect on the strength of screw threads produced by different

clearances in the pitch diameter of the threads of a bolt and nut

assembly. The clearance was varied from 0, or a snug fit, to 0.049

inch. The results showed that for clearances up to a certain value the

strength of the screw threads remained about the same, but clearances

above 0.03 inch for a ^r-inch 16-thread assembly A'ery materially

reduced the strengtli of the threads. It was also found, as would be

expected, that the greater the number of threads per inch the greater

is the decrease in strength caused by any given clearance.

The investigation also covered the effect of variations in the

angle that the face of the nut makes with the plane at right angle to

the axis of the bolt. This angle was varied from one-half minute

to six degrees. The results shoAved that the strength of the scre\Y

threads was not affected by this cliange.

Streamline Stay Rods.

For the subcommittee on metals of the National Advisory Committee for Aeronautics a specification was prepared for the purchase

of these important parts of an airplane structure. The pilots and

others connected with the operation of airplanes feel tbat these

streamline rods are unreliable, and that crashes often result from

their failure, due possibly to fatigue.

Taking the Bureau of Construction and Repair, Navy Department

Specification No. 61, as a basis a very careful and thorough study
180 I5EP0RT OF DIRECTOR OF BUREAU OF STANDARDS.

was made of all available data and a ncAV specification j)repared. A

better distribution of sizes Avas made, so as to obtain more nearly

a geometrical series, and the tolerance in sectional area was also

graded. The British standard fine screw thread close fit was recom- mended, -.ill the dimensions and idtimate strengths were recomputed

and diagrams made to compare the proposed values with those in

the above-mentioned specification.

The material, method of manufacture, protective coating, method

of test, and inspection were all carefully considered by the subcommittee and every effort made to prepare a specification which would

insure the best streamline rods which could be manufactured at the

present time.

It was found impractical to require fatigue. X ray, or magnetic

tests at this time, but the use of these tests is urged in the hope

that they may prove reliable in eliminating unsuitable material

which occasionally gets into service at present.

Investigation of the Failure of a Duralumin Airplane Elevator.

An elevator from a J. L. postal airplane was submitted for test to

determine the cause of the disintegration of the duralumin tubes

and sheets of which it was made. The elevator,, which had only been

in service two months, showed brittleness at the trailing edges

where portions of the sheets forming the elevator surface had broken

awa}^ Tests showed that the brittleness extended for several inches

from the edge and occurred where two sheets were in contact. This

may be due to electrolytic or to chemical action upon an overworked

material, starting near the rivets where high local stresses occur and

where moisture may accumulate. The behavior of this material

shows that further study and investigations are needed if the light

allo3's, particularly those containing aluminum, are to he used with

safety for aircraft construction.

Calibration of Large Testing Machines. '

f 'alih ration, of ^flOOflOO-poinid (luihi-Tcst'nu/ Mac/i!ne at the

BoHton Navy Yard.—A comparison calibration of the 2,000,000-

pound chain-testing machine located at the Boston Navy Yard Avas

made b}' the calibration bar. extensometer method. A large 5;|-inch

diameter bar of nickel steel was used for this ]nu'pose and the deformation measured by means of a special extensometer. The bar was

first loaded in the large Emery machine of the Bureau and the

elongation measured for increments of load of 10,000 pounds. Six

runs to 1.000,000 })ounds were made. The bar and extensometer

were taken to the Boston Navy Yard and six loadings to 1,000,000

Avere made in a similar manner. A comparison of the results obtained from both machines indicated that the chain-testing machine

Avas reading about 3.4 per cent higher than the large Emery

machine.

Oalihratlon of a 1 fiOO/)00-po}i)id Ilydruidic Press.—A comparison

calibration of a l,00(),000-pound hydraulic press belonging to this Bureau Avas made by the calibration bar, extensometer method. A special

4-J-iuch diameter compression bar 28 inches long Avas used. Several

loadings to 1,000,000 pounds Avere made both in the large Emery machine and in the hydraulic press and the deformation determined for
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 181

increments of loading of 10,000 pounds b,y means of a special extensometer. From the results a comparison calibration curve was

obtained. It was found that the hydraulic press was retiding about

1.2 per cent liigher than the large Emery machine.

Investigation of Oxyacetylene Welding and Cutting Blowpipes.

At the request of the War Department the Bureau conducted an

investigation of the operation, efficiency, and safety of oxyacetylene

Avelding and cutting torches. A])paratus from 11 of the most prominent manufacturers was tested. All tests were conducted under

standardized conditions, the practical work of cutting and welding

l^eing carried on by a grou]) of experienced welders and cutters,

who were directly under the charge of the Bureau. Every effort was

made to secure data that Avould be representative only of the blowpipe action.

As a result of this investigation it Avas determined that none of the

commercial cutting blowpipes procurable are designed according

to any definite theor_y; that none of the cutting blowpipes are effi- cient in cutting metal of all thicknesses, and probably that considerable improv ement can be made in economy in cutting 2-inch' metal

and possibly in other thicknesses. The results of the investigation

I would also indicate that ijrobably the maximum thickness of metal

that may be cut economically with oxyacetylene bloAvpipes is in the

neighborhood of 12 inches.

With regard to the welding Idowpipes. this investigation i^roved

conclusively that none of the blowpipes submitted for test were

correctly designed. As a result of improper design none of the

welding blowpipes ])roved free from flash-back ]3henomena. Most

of them, therefore, are not fundamentally safe i^ieces of apparatus

and. further, the inherent defects in design result in the making of

unsound welds. This latter condition has generally been attributed

to the operator, and as the result of the frequency with which un1 sound welds occur the oxyacetylene fusion welding process has been

rather severely criticized. It is believed that the results of the

investigation show that with a properly designed welding blowpipe

satisfactory fusion welds may be made.

Summary of Tests.

' The following statement shows various materials tested by this sec- tion during the fiscal year ending June 80, 1921, together with the

number of specimens of each type :

Metals.

Iron and steel

ijiiM ivdu 24

Steel 517

541

I ==

Ahiininnni and aluniimim alloys:

Ahnniniiiii alloy 21

AInniiniini alloy, duralumin ' 70

AhiiHinuin alloy, elektron 3*^
182 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Copper, brass, and bronze:

Brass

Copper 19

29

iVfiscellaneous metals and alloys

Bearing metal, " ceco (5 Dental amalgam , q Dow metal ;

, q

Monel metal _. g

26

Fiber rope and wire rope. Rope, man i la 155

Rope, wire , 21

Scout guard rope . 2

Cordage 32

210

Other vuitcrials. Hard iiorn liber 26

Redmanol 3

29

Calibration of testing machines.

Scotl type Q 1

Miscellaneous.

Bars, clay 80

Belting 7

Body bolts : IT Bomb points 4

Bomb lugs 6

Bolts and nuts 37

Cable, current meter 1

Cbaiii, sasb IS

Chain, skid 1

Chisel, cold 6

Chisel, track 1 Enantel for sheet ii'on 18

Gears 7

(ilass, port and skylight 30

Grating, reticulated 2 Hooks, tent 10

Keyway.s tor armor plate 6

Seals, Acme -1 Springs, bed 2

Terra cotta 396

Weiibiug - 10

Wire, brass , ^ 8

Wire, bronze ' 8

Wire, magnet 37

Wii'e, music , , _ 60

Ttciiiforced conci'ete columns 4

780

Publications.

The following is an enumeration of the publications which were prepared by this section
REPORT OF DIRECTOR OE BUREAU OE STAi^DARDS. 183

Bureau of Standards Circular 101, Physical properties of materials.

An investigation of oxyacetylene \Yelding and cutting blowpipes (R. S. Johnston), in press. Results of some tests on manila rope (A. H. Stang and R. K Strickinberg),

in press. MEMORANDUMS.

Memo VII-1-16: Dimensions and tolerances for the cross-sections of streamline stay wires.

Memo VII-1-18A: Streamline wire specifications.

Memo VII-1-19 : Impact tests for woods.

OUTSIDE PUBLICATIONS.

Hardness testing of metals (H. L. Whittemore).

Article in " Mechanical engineering," July, 1921.

General Information. Furnished.

Many engineering students, as well as engineers, business men, and

others from this and foreign countries, were shown through the test- ing laboratories. Many of them were seeking information on testing

equipment, particularly as to the merits of certain type of machines.

Advice has been furnished and recommendations made concerning

rope specifications, methods of testing balls and rollers and the re- sults obtained, metal airplane construction, methods of measuring

hardness of metals, methods of measuring the impact resistance of

metals, methods of determining the fatigue resistance of metals,

methods of testing lock nuts, solving mathematical problems, and

working pressure of an autoclave.

CEMENT, CONCRETE, STONE, GRAVEL, AND SAND.

General Outline.

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 concrete

construction, development of new uses for cement products, the distribution of knowledge concerning their use, and the design and

fabrication of concrete structures. , The Bureau acts as a testing

laborator3^ for a considerable part of the cement used in the Government's construction work as far as its facilities permit.

The work of the section may be classified under two main headings: (1) Investigations or researches, (2) inspection and testing of

cement. These necessarily overlaj:) to some extent, as a certain

amount of material testing is carried out by those engaged in re- search, and a considerable amount of investigative work is done in

connection with cement inspection and testing. The available funds,

however, are about evenly divided between the two classes of work,

and it is convenient in many respects to maintain this classification

for reference pitrposes.

The first group is subdivided into several lines of investigative

work, as follows: (1) Constitution of Portland cement, (2) plastic

magnesia, (3) stucco and plaster, (4) reinforced concrete, (5) durability of concrete in alkali and sea water, (6) building stone, (7)

volume changes in concrete, (8) general concrete investigations,

(9) fineness, (10) concrete tanks for oil storage.
184 REPORT OF DTREOrOR OF BUREAU OF STANDARDS.

Xot all of these investigations liave been actively pursued during

the past year o\Aing to lack of funds, but it is hoped that work on

the most impoiiant of them at least can be continued later.

Under inspection and testing of cement is included the Avork of

sampling, testing, and ship[)ing of the cement purchased b)^ the

seA'feral departments of the Govenitnent. For carrying on this work

laboratories are nuiintained at Washington, D. C. ; Northampton

and Pittsburgh, Pa.; Denver, Colo.; and San Francisco, Calif. The

laboratories in Pennsylvania are engaged only in the testing of

cement, and the other branches are equipped to do a limited amount

of concrete and miscellaneous testing.

Constitution of Cement.

In order to advance the work with Sorel cement no nev,- work was

inaugurated dealing with the constitution of Portland cement.

There were placed in j>ress the results of the investigation of the

properties of the aluminates high in lime. These at early periods

produced strengths much in excess of those produ.ced by Portland

cement either on a mortar or concrete. The strengths developed

at three years were also very high, though when the aluminates were

commercially free " of silica there Avas a reti-ogression in strength

between the one and three year period. In those cases when silica

had been added the strengths were lower, but showed a continuous

increase witli age. The presence of calcimn sulphoaluminate was

noted in a munber of the mortar briquettes in large amounts, but

in no case had it produced disintegration. It appeared in the voids

in the form of a mass of loosely bound acicular crystals. This is the compound sujji^osed to produce disintegration in concrete submitted to the action of sea Avater. HoAvever, in these particiilar

specimens it ajipears in much greater quantities than eA'er noted in

sea-Avater concrete. l)ut has not i')roduced any signs of disintegration.

Sorel Cement.

SeA'eral lots of magnesite from different localities, after crushing

and grinding in different sizes, haA'e been calcined under closely

controlled conditions as to temperature and length of time of burning. From the resulting calciae seA'eral typical mixtures of both

a flooring and a stucco conijiosition haA'e been made. These have

been made into the usual laboratory test pieces and in addition have

been placed in service in the form of panels of flooring and stucco.

The Avorlc has not advanced sirfficiently far to permit of draAvin<j;

any final conclusions. IToAveA^er, almost Avith the first mi.xtures made

there Av as noted the marked effect Avhich different aggregates produced upon the same calcine. Tims a calcine Avhich produced a large expansion Avith one mixture of aggregates was satisfactory

Avhen the mixture was changed. The lean stucco mixtures are not

as sensitiAe to differences in the ]:)roperties of the calcined magnesite as ai"e the richer flooring mixtures.

Test of a Concrete and Hollow-Tile Floor Reinforced in Two

Directions.

The structure tested (referred to as the Waynesburg slab) is a large slab made up of clay tiles and reinforced concrete ribs. In the

Annual Report for 1920, page 189, a description is given of the test
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 185

referred to. As stated in that description the loads originally applied did not cause failure of the slab, and in order to obtain further

information additional load tests were made in November, 1920. In

this test three panels were loaded in the effort to bring about failure

and thus to determine the real factor of safety. After the loadingmaterial had been piled 22 feet high it seemed unsafe for the workmen to continue operations and the test was discontinued. On

account of the fact that the test could not be carried to failure it is

not known how great a load could safely be permitted on that slab,

but that the test results indicate possibilities for economy in building

construction will be evident from the following statement:

Current standards for design woiild permit as safe live loads on the

slab tested 33 pounds per square foot for the 16-foot square panel

and IT pounds per square foot for the 16 by 19 foot 3-inch panel,

while the 16 by 22 foot 6-inch panel would not be adjudged quite

heavy enough to carry its own weight. Trie loads actually placed on

the panels of three sizes were 1,-113, 1,184, and 920 pounds per square

foot, respectively. Reduced to e(}uivalent uniform load they are approximately 1,300, 1,090, and 850 pounds per square foot, respectively,

and correspond to factors of safety of 16.2, 17, and 18.6 for the three

sizes of panel, if the design loads be based on current standards for

design. These loads were applied in November, 1920, and nearly

eight months later (June 30, 1921) they are still in place and have

not caused failure nor excessive increase in deflection.

Moments and Stresses in Slabs.

About a year ago the Bureau undertook in cooperation with the

American Concrete Institute a study, by analytical methods and by

correlation of test data which had been secured by various agencies

during the past 10 years, of the subject of moments and stresses in

slabs. This study included " flat slabs "—that is, concrete slabs " having reinforced bars extending in two or more directions and having

no beams or girders to carry the loads to the sujiporting columns "

and reinforced concrete or tile and reinformed concrete slabs supported on girders, such, for example, as the Waynesburg slab. The

analysis developed in this study is probably the most complete which

has yet been made, and a comparison of the results of the analysis

with the stresses developed in the tests studied indicates a fair agreement between the anal^'sis and the tests for loads which cause stresses

within the yield point of the reinforcement, but the reserve strength

which is developed after the yield point of the reinforcement is reached appears to be much greater for the slabs tested than for the

individual units ordmarilj' tested in laboratories. In most designs no account is taken of the tensile strength of the concrete, but the

indication from the tests is that the tensile strength of the concrete

is a source of considerable additional strength for reinforced concrete

slabs, and possibly also for continuous beam construction. The re- sults of this investigation have formed the basis for the specifications

for flat slabs referred to in later paragraphs. These specifications were prepared by a member of the Bureau's stafl'. Specifications for Concrete and Reinforced Concrete.

A member of the staff is a member of the joint committee on standard s]3ecifications for concrete and reinforced concrete. This joint

committee is made up of five representatives from each of the fol131
186 EEPOET or DIKECTOR OF BUREAU OF STANDARDS.

lowing organizations : American Society of Civil Engineers, American Society for Testing Materials, American Railway Engineering

Association, American Concrete Institute, Portland Cement Association.

This joint coimnittee has just made public its first progress report,

and through the committee the Bureau has taken an important part

in the formulation of the specifications. In the work of preparing

these specifications the investigations of the Bureau, previously re- ferred to under the heading of " Test of a hollow tile floor reinforced

in two directions " and " Moments and stresses in slabs," have been

of much vakie. The possession of other data has also placed the

Bureau in a position to be of assistance to the committee. Among

these other data are the results secured by the Bureau from the investigations by the concrete ship section of the Emergency Fleet

Corporation and from the technologic branch of the Geological Survey about 1910.

Shearing Strength of Concrete Beams.

Although the results of the shear tests made on concrete beams in

connection with the concrete ship investigation (see p. 207 of Annual

Report for Year Ending June 30, 1919) have not yet been j)ublished,

the results obtained have received recognition in the progress report

of the joint committee on standard specifications for concrete and

reinforced concrete. Lectures presenting the results of these investigations have been given at ditferent jilaces, and much interest has

been shown in the results attained.

Durability of Concrete in Alkali and Sea Water.

Owing to reduced appropriations little has been accomplished during the past year. An attempt has been made, however, to keep in

touch with the work caiTied on by other agencies, and laboratory

tests have been undertaken by the Chemical Division of the Bureau

to determine the efficacy of bituminous coatings as a protection for

cement drain tile against alkali attack. The report on the condition

of the several experimental installations of drain tile in the West,

based on the inspections of 1919 and 1920, has not yet been completed.

This report will probably be published as a Technologic Paper, supplementing Technologic Paper No. 95, during the coming year.

Automatic Freezing and Thawing Apparatus.

A hew freezing unit has recently been installed in connection with

this apparatus, the purpose of which is to enable one to make a large

number of freezings and thawings with minimum loss of time. Instead of determining the effect of a small number of freezings on the

strength and appearance of a material, as the test is usually made, the

procedure is to determine the number of freezings which produce

complete disintegration. This is belicA'ed to be a more definite means

of comparing the weather-resisting properties of materials. A large

amount of work is planned in connection Avith this investigation, including tests on building stones, stucco, terra cotta. slate, and the

effect of waterproofing materials in preventing disintegration.

Discoloration Tests on Indiana Limestone. , The problem of determining and eliminating the cause of stains

on masonry of this important material was undertaken more than

a year ago. Twelve panels of the limestone were erected on the
REPORT OF DIRECTOR OF BUREAU OF STANDARDS 187

industrial building in September, 1919. These panels were set up

in mortars of various cements, using different combinations and

methods of waterproofing. These tests were of value in a general

way, as they served to indicate the source of the trouble, but it was

soon learned that more severe conditions were necessary in order to

produce definite results. The study of the panels and of limestone

buildings indicates that it is only in the parts of the structure where

a large amount of water penetrates the stone and leaches through the

mortar joints that the stains occur in appreciable amounts. Hence,

in order to determine more definitely the effect of different cements,

tests were made which gave exaggerated conditions. Water was

made to leach continuously through the mortars and limestones for a considerable length of time. Tests of this kind indicate that some

cements produce a much more marked stain than others, but that the

stains will not always occur with the same cement. White cements

and lime mortars also produce stains, but usually less intense than

normal Portland. The indications are that the stain in question

that is, the brown discoloration frequently called " iron stain "— is due to a small amount of organic impurity in the limestone. Water

in leaching through the mortar appears to become a solvent for this

oi'ganic matter, which is carried to the surface, where it is deposited

as the solvent evaporates. The organic impurity in the limestone

varies, and hence stains may occur in one part of the structure while

another part subject to the same conditions may remain free from

stains. Waterproof materials are being experimented with as a means of preventing the leaching of water through the mortar and

limestone. So far no cement has been found that will not produce

stains on the limestone when a large amount of water leaches

through.

Colorless Waterproofing Materials.

An extensive series of tests is in progress on colorless waterproofing materials applied to natural stone. These tests include exposure

tests to determine the durability and effectiveness of the coatings to

prevent the obsorption of water ; freezing tests to determine the value

of the materials in preventing frost action; and carbonic-acid tests

to determine the effect of, carbonic atmospheres on treated speci- mens. A preliminary report is being prepared giving the results of

exposure tests for a period of six months.

Investigations of Slate.

Samples of slate from various quarries are being collected, and

tests are in progress to determine the physical jjroperties of the

various materials. Special attention will be given to the effect of

ribbons on the strength and other properties of the slate.

General Tests on Concrete Floor Treatments.

The sections of concrete floor in the corridors of one of the Bureau's buildings which were treated with various concrete floor treatments have now been in service three years. These have been

studied with a view to determining the relative value of the various

treatments. Four distinct types have given good service with very

slight signs of wear during this period. Some of these are nonproprietary and are very inexpensive. A rejiort is available which
188 REPORT OF DIRECTOR OF BUREAV OF STANDARDS.

describes the nature of the materials under test, the methods of

application, and the resiilts of observations on the treated panels

after two years of service.

Volume Changes in Mortars and Concretes.

This Avork has been discontinued except for continuation of the

measurements on mortar slabs made up last year. The first phase

of the investigation—that is, its bearing on the durability of stuccos

was practically completed and very valualile information was obtained. It was shown that the amount of shrinkage in moi'tar coats

was largely dependent upon the amount of water retained in the

mortar when set occurred, and that the elimination of the excess water resulted in a marked reduction in the shrinkage. The removal

of excess water can be brought about by control of the " suction '* or

absoi'ption of the undercoats, wliich thus becomes an important factor in good stucco work.

Air Analyzer. ^ This apparatus was developed at the Bureau some years ago in

connection with the study of the effect of fineness of Porthmd cement

and has been found applicable to fineness determinations of other

materials. During tlie past year a considerable amount of eifort has

been devoted to modification of the apparatiis in such a way as to

adapt it to making finer separations and also to enable it to handle

softer materials. By revei'ting to the old principle of blowing air

upward through the sample of material under examination and ac- curately controlling the velocity- of the air by u.sing a flow meter of

the type described in the Bureau's Technologic Paper No. 183 suc- cessful fineness determinations have been made on such materials as ochre, hydrated lime, x^laster of paris. etc. Moreover, the size of

separation has been reduced to approximately 10 microns; that is. the

diameter of the largest particles removed by the smallest air current

is about 0.01 millimeter, or about one-tenth of the diameter of the

largest particles passing a Xo. 200 sieve. It is thus j^ossible to obtain

a better idea of the fineness of powders which have heretofore lieen

analyzed by less accurate sedimentation methods.

Standard Cement Sieves.

During the year 173 Xo. 200 cement sieves were standardized as compared with 56 standardized in the fiscal year 1920 and 56 in 1919.

This is an increase of over 200 per cent. It is believed that at the

present time no difficulty should be experienced in obtaining Xo. 200

sieves meeting the standard specifications.

U. S. Standard Sieve Series.

As noted in the Annual Eeport for 1920. specifications for a new

series of standard testing sieves have been developed in cooperation

with the "Weights and ileasiires Division of the Bureau. In connection Avith the standardization of these sieves the present specifications

ai'e liased oi\ly upon average measurements of oi^enings and wire

diameters, with certain tolerances upon these averages and upon the

maximum o])enings. It is recognized, liowever. that appreciable

differences in sieving values of sieves meeting tliese specification.--
REPORT OF DIRECTOR OI'' BUREAU OF STANDARDS. 189

will exist, purtieiilarly in the finer sieves, and data will be obtained

as the new sieA'es 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 accuracy are required. At

the present time correction factors are determined only for No. 200

sieves that are submitted for standardization, the standard cement

fineness sample being used for this purpose. It is planned eventually

to prepare standard samples whereby correction factors may be determined for sieves finer and coarser than the No. 200 in the U. S.

itaiidard sieve series.

Sieves may now be obtained from two manufacturers that are made

according to the U. S. standard sieve series and a third manufactures a series of testing sieves of which the majority nominally con- form to these specifications.

Standard Samples.

The Bureau pre});! res and keeps on hand for issue standard fine- ness samples of cement for checking up No. '200 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 accom])anied by full directions 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 No.

•JOO sieves may be compared with the Bureau's standards and correction factors obtained. These samples are also used by the Bureau

in checking up its own sie-^'es and in the standardization of No. 200

sieves submitted for certification. The two samples on hand at

present are 46g-78 per cent passing the No. 200 sieve and 47c-89 per

cent passing the No. 200 sieve.

Concrete Tanks for Oil Storage.

This investigation Avas undertaken in 1918 at the recjuest of the

Na-\y Department and the Emergen'cy Fleet Corporation, and has

since been continued as an industrial problem. The work has been

devoted largely to determining the seepage losses Avhich occur in

well-fabricated concrete tanks of 1:1^:3 mixtures filled with mineral oils, covering practically the entire range of fuel oils from light

gasoline to heavy road oil. This portion of the investigation has

been practically completed and a report has been prepared for later

publication giving the results both of laboratory- work and extensive

field inspections. Taking into account the nature of the test tanks

and the conditions undei' which they were made in relation to the

conditions obtaining in actual field construction, the general conclusion has been reached that well-built concrete tanks are suitable

for the storage of fuel oils up to about 35 or 40° Beaume, and that

the losses of such oils by seepage should be practically negligible.

On the other hand, the investigation indicates that the use of concrete tanks for storage of kerosenes and gasolines is hardly warranted except under special conditions, and that tanks vv'hich are designed and built for this purpose sliould be thoroughly tested for

permeability before being put into service.

A considerable amount of work has also been done on the testing

of so-called oil-in-oof coatings and treatments. In general, it has
190 KEPOBT OF DIRECTOR OF BUREAU OF STANDARDS.

been found that none of the treatments tested are sufficiently effective to warrant recommendation of their use. Tin foil applied over

the interior surface of the tanks with spar varnish is the only treatment which promises to reduce the losses of the lighter oils to

negligible quantities. Data have also been obtained on the effect of

pressure on rate of seepage, on the relation of viscosity to rate of

seepage, and on the tightness of joints between sections of con;-rete

placed at different times.

Measuring the Consistency of Concrete.

Further comparisons have been made between the slump and flow

table methods of measuring consistency of freshly mixed concrete.

The general conclusions from these comparisons may be summarized

as follows

For measuring the consistency of rich or easily workable mixtures

both methods are satisfactory and give results which are in close

agreement. In the case of leaner and harsher mixtures, the slump

test does not function properlj^ until the consistency is relatively

wet, and then only over a narrow range. On the other hand, the flow

table gives consistent readings on mixtures of all proportions

throughout the workable range. It has also been found that the

variation in making repeated consistency measurements on any given

batch of concrete is less with the flow table than with the slump test. The chief objection to the flow table at the present time is that it

needs standardization in order that results obtained in different

laboratories may be directly comparable. As this standardization

requires only a general agreement among testing engineers as to the

design of the flow table without necessitating extensive investigations as to the effects of various factors, it is to be hoped that the

American Society for Testing Materials will soon take steps to prescribe unifoi'm dimensions for this very useful piece of laboratory

equipment.

Measuring the Time of Set of Concrete.

The flow table has been found useful in determining the time of

set of a concrete mixture. From the time when mixing is completed a batch of concrete gradually loses plasticity, or flowability,

a property which the flow table is designed to measure. The time of

set occurs when the concrete changes from a plastic to a rigid body ; that is, when the point of zero flow is reached. By molding a series

of test specimens and determining their flow at intervals after

molding the time elapsed between mixing and the point of zero flow can be determined. In the testing of neat cement it has been found

that this method gives close agreement with the Vicat needle method

for the time of initial set. In practical applications the method

has been found useful in determining the effect of various admixtures on the time of set of concrete—e. g., hydrated lime and calcium chloride—and serves to indicate the length of time during

which a conci'ete mixture retains a sufficient degree of floAvability

for proper placing. Detailed results of this investigation were presented in a paper before the American Society for Testing Materials in June, 1921.
KEPOKT OF DIRECTOR OF BUREAU OF STANDARDS. 191

Tests of Concrete Used in Georgetown Bridge.

Concrete is the principal building material used in the construction

of the new arch bridge across the Potomac Eiver to replace the old

Aqueduct Bridge at Georgetown. The concrete laboratory of the

Bureau has been cooperating with the officers of the United States

Engineer Corps in charge of the work, and samples of the concrete

obtained at the time that the various sections of the bridge were

being poured were tested. During the year over 500 concrete test cylinders, 6 by 12 inches in size, were tested in compression, these

specimens being taken during 125 days of concrete pouring. In

addition to this work samples of cement, sand, and gravel used in

making the concrete were tested from time to time.

Concrete Accelerators.

Tests of concrete accelerators have been continued during the year.

In the latter part of the year a series of tests on the calcium chloride

type of accelerators was being carried out in cooperation with the

American Society for Testing Materials. In this series opportunity

was taken to acquire additional information on hand mixing v. machine mixing in the testing of concrete and also upon the relative

uniformity to be obtained from mortar test pieces in the form of

cubes, cylinders, and prisms. In general it may be stated that the

calcium chloride type of accelerator apparently has a beneficial effect

on most Portland cements, not onl}^ in increasing the early rate of

hardening but also in tending to correct such faults as quick set- ting and unsoundness. A limited number of experiments were

made to determine the effectiveness of calcium chloride in coldweather concreting, but inability to control or predict weather conditions led to the postponement of further tests along this line until a refrigerating system was available in which the desired temperatures could be maintained. It is possible that this work may be

resumed during the coming year.

Slag as Concrete Aggregate.

A blast-furnace slag from banks in Virginia was tested as a concrete aggregate in comparison with local gravel. The strength

results confirmed previous tests of the Bureau that blast-furnace

slag as a coarse aggregate is capable of producing just as strong

'concrete as gravel, the conditions of the tests beinej the same. The bulletin issued last year by the Bureau on Blast Furnace Slag- as Concrete Aggregate is being revised and the new issue Avill contain general information on production, tests, and specifications, to- gether with a short bibliogi'aphy on the subject.

Investigation of a Special Cement.

Throughout the year work has been jjrogressing on a Portland

cement treated by a special process of English origin, for which

unusual claims were made in regard to waterproofing and oil-proofing properties. The product Avas also stated to have greater strength

than the normal Portland cement. As the principle involved in this

process had long been known and recognized by cement chemists, the

Bureau felt justified in undertaking a limited investigation of the

material, and a more extensive program was made possible by the

interest of a Canadian company, who supplied a research associate
192 REPORT or DlPxECXOK OF BritEAU OP STANDARDS.

for this problem during a period of 11 months. In view of general

interest in the use of concrete tanks for oil storage and in view of the

claims made for the treated cement, parti cularlv as to its suitability

for tlie construction of petrol reservoirs, tlie Bureau's work was

largelj^ devoted to a study of the permeability of concrete made with

the special cement in comparison with that made with normal—that

is, untreated—cement from the same source. The work of this investigation is approncliing completion, and a final report Avill be

rendered early in the coming fiscal year. It is evident, however, that

the claims for the prodiict in regard to impermeabilit}' will not be

borne out by the tests. Just what degree of merit the product may

be entitled to can not be decided until the results of all the tests are

available.

Miscellaneous Tests.

The usual number of tests of concrete aggregates and miscellaneous

materials have been made during the 3^ear. Most of these were submitted by Federal Government agencies in various parts of the country, a considerable number were submitted by State governments and

State highway departments, and a few were submitted bv manufacturers or private concerns. Including the work of the Denver and

San Francisco laboratories, the materials tested were concrete aggregates from many sources, building stones, slates, alkali salts, soils

and waters, various materials for fineness determinations, defective

concretes, copper ore waste, slags, accelerators, floor hardeners, waterproofing compounds, reinforcing steel, galvanized sheet metals, adulterants in lye, gasoline, boiler watei'S, and paints.

Testing of Cement for Government Purposes.

The quantity of certified cement shipped to Government projects

was smaller than in the preceding year. Hovi^ever, thei'e is shown in

the table below an increase in rate at the end of the fiscal year, and

it is not expected that the next fiscal year will show any further

marked decrease in the demands. The cement was used for river

development, irrigation projects, bridges. District of Columbia parks,

l^ublic buildings, naval bases, Arm}^ camps, depots and fortifications,

Panama Canal, hospitals, arsenals, explosive plants, and island possessions. Among the offices served were Army, Navy. Reclamation.

Shipping Board, Indian Affairs, and Public Buildings and Grounds.

Shipment of tested cement Cbarrels).

Montli.

1918-19 1919-20 1920-21

July

August

September.

October. .

Noi'ember. December.

January . .

February.

March

April

May

June

1,121.960

1.0.-.3,167

i,or>3;fi98 948, 937

719', 711

247; 137

186,806

1,82,26.') 311,210

280, £29

2r-,^, 646 227,857

144, 421 168,141

1.38,164 133,462

lis; 648

80,9.39 79,894

66, 28.-, 70, .S3.", 79,590 53,798

56,605

99,8^19 63.625 52,460 93,532

75,.305 59,389

24,860 29,605

,57, ,515 .54,054 59,129

89,698

Total

E.xcludins Panama Canal.

Rejections

6,588,923

6,403,9?3

742.000

1.190,782

i; 044, 0,32 125,919

7,59. 051

724; 051

86,6,52
BEPORT OF DIRECTOR OE BUREAU OF STANDARDS. 193

Inspection was made at more than 50 shipping points located in

the District of Cohimbia and the following States : California, Colorado, Indiana, Kansas, Kentucky, Maryland, Missouri, Montana,

Nebraska, New Jersey, New York, Ohio, Oklahoma, Oregon^ Pennsylvania, Texas, Utah, Virginia, Washington, and West Virginia.

In the gradual return to prewar conditions the Bureau's cementinspection service was withdrawn early in the fiscal year from mills

in the Dallas, Birmingham, St. Louis, Louisville, Chicago, and Hudson districts. Inspection was also discontinued at one mill in the

Washington (D. C.) territory. Some large Government orders were

subsequently placed at mills thus eliminated.

The Bureau's cement-inspection service frequently involves much

special sampling, investigating, and testing not included in the regular routine of cement testing. Thus, numerous samples were received

for comparative tests, others for referee tests where quality was in

dispute, and samples of four cements from foreign countries were

submitted for determination of their properties. The importance of

testing cement prior to use has been emphasized in numerous instances. In one case the samples submitted were found to have

extremely low tensile strength, in another the wholly unsatisfactory

quality of cement proposed for use in the construction of concrete

boats was established, and in still another case cement obtained

through the salvage board and shipped across country for use in con- structing bridge piers was found to be finely ground silica sand.

One other feature of special service is worthy of mention, and that is

the assistance rendered a number of American cement manufacturers

in having their product approved for the South American market.

The labor involved in the process of obtaining the required certificates to accompany the special reports on a lot of test shipments is

quite as great as the labor of testing and making the shipments. It

is, however, a service that only the Bureau can render, and one which

it should render whenever such service is required.

Foreign Cement Specifications.

A large number of replies were received to inquiries regarding

cement specifications made through the various consular agents in

other countries. The chief requirements of these specifications have

been briefly summarized in a chart, which will soon be available for

distribution in printed form. In addition these specifications have

been more fully set forth in a larger report. In the latter are described many of the details of the methods used by the different

countries in making the various tests. The larger compilation should

be of interest to laboratories, not as setting forth procedure to be

followed by them, but because it describes and illustrates manv of

the methods and devices and offers some possible ground for suggestions tending to improve present methods.

Publications Relating to Cement and Concrete.

Publications by the staff of the cement section include the following, which have appeared during the year

Technologic Paper No. 173, Tests of bond resistance between concrete and steel (W. A. Slater, F. E. Ricliart, and G. G. Scofleld).

Technologic Paper No. 174, Effects of cal as an accelerator of the hardening of

Portland cement mixtures (Roy N. Young).

64984—21 13
194 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Technologic Paper No. 175, Pouring and pressure tests of concrete (W. A. Slater

and A. T. Goldbeck).

Technologic Paper No. 182, Effect of repeated reversals of stress on doublereinforced concrete beams (W. A. Slater, G. A. Smith, and H. P. Mueller).

Report of service tests on concrete floor treatments (D. W. Kessler), mimeographed circular issued by the Bureau in October, 1920.

Moments and stresses in slabs (H. M. Westergaard and W. A. Slater), Proceedings Am. Concrete Inst. ; 1921 . Further tests of concrete tanks for oil storage (G. A. Smith), Proceedings

Am. Concrete Inst. ; 1921.

Shrinkage of Portland cement mortars and its importance in stucco construction (J. C. Pearson), Proceedings Am. Concrete Inst.; 1921.

Effect of age of test pieces in soundness tests of Portland cement (J. R.

Dwyer), Concrete, December, 1920.

Relation between tensile and compressive strengths of cement mortars (J. R.

Dwyer), Concrete, June, 1921.

Time of set of concrete (Watson Davis), Proceedings Am. Soc. for Test. Mat;

1921.

Plastic magnesia cements (P. H. Bates and R. N. Young), Jour. Am. Ceramic

Soc. ; 1921.

LIME, GYPSUM, AND SAND-LIME BRICK.

General.

The work of this section has to do with the development of standards for these materials, the improvement of manufacturing processes to produce better or cheaper materials, and the collection and

dissemination of knowledge which will lead to their more efficient use. The work has been devoted largely to the development of new

testing methods and the obtaining of test data for use in the

preparation of standard specifications. It has been the custom for

a representative of this section to visit manufacturing plants oc-, casionally in order to keep in touch with developments in the industries. During this year 23 lime plants and 1 gypsum plant in Pennsylvania, Virginia, and North Carolina were visited.

Hydrated Lime in Concrete.

Much experimental work has been done to determine what effect

the addition of hydrated lime has on the properties of concrete.

Previous i-esults have been criticized because it was believed that all

concretes should be brought to the same degree of workability before

their other properties could be compared and no method of measuring workability seemed satisfactory. A machine for measuring

plasticity has been built, and experimental trials indicate that it

will give the expected results. The measurement of this property,

together with the measurement of consistency by means of the flow

table, should give an indication of the workability. Preliminary

experiments have been completed by this section and plans have

been laid to obtain field data on the same subject in connection with

the building of a concrete road by the Bureau of Public Koads.

Panel Tests of Lime Plaster.

Publication of the Bureau's report on the cause of popping of

lime plaster has led to a great deal of discussion. As a result ar- rangements have been made to conduct further experiments on a

semifield scale. This work will be conducted under the joint supervision of the Bureau, the National Association of Plastering Contractors, the International Plasterers' Union, and the National Lime
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 195

Association. It will consist in the erection and plastering of fullsized partitions at the Bureau under carefully controlled conditions.

Measurement of Plasticity.

The instrument designed by this Bureau to measure the plasticity

of hydrated lime has received the official sanction of the National

Lime Association. After examining nearly all the brands of hydrate

on the market it was decided that a plasticity figure of 200, as determined by this machine, is the limiting figure for a finishing hydrate ; that is, a hydrate having a plasticity of 200 or more can be

used for the finish coat of plaster. This requirement has been inserted in the tentative specification for finishing hydrate of theAmerican Society for Testing Materials. Arrangements have been_

concluded whereby plasticimeters are being manufactured for sale.

Quick Setting of Lime Plaster.

One of the points of dilference between a lime plaster and other

plasters is that the lime sets slowly. In general, it can not be stated

that this is either an advantage or a disadvantage, but under special

conditions it is sometimes desirable to be able to make lime plaster

set quickly. The first step was to devise a means of measuring the

time of set of lime plaster. This required some months of experimental work, but a satisfactory means of making this measurement

is now available. The problem is now to find some way to treat the

lime or something to add to the lime in order that its time of set may

be controlled.

Normal Consistency of Sanded Gypsum Plasters.

In the tentative specifications for gypsum plasters issued by the

American Society for Testing Materials it was stated that when test- ing both neat and sanded plasters they should be mixed with enough

water to produce a paste of a definite consistency. Since sanded

material is used at a drier consistency than neat material, it was felt

that this method of testing was wrong. The Bureau was asked to

designate a standard consistency for sanded plasters. This work

has been completed and the results adopted.

Effect of Fineness on Other Properties of Calcined Gypsum.

Every specification for calcined gypsum contains some requirement as to the fineness of the material. These requirements have

been based, as a rule, upon what the trade is accustomed to produce

rather than upon the actual needs of the consumer. The Bureau

therefore planned to obtain data which would form a fair and rea- sonable basis for the fineness requirements. This work has been

completed and published.

Plastic Gypsum.

Calcined gypsum is not sufficiently plastic to be entirely satisfactory as a plastering material. Other substances are added to it in

order to make it spread better under the trowel and to carry more

sand. The use of these other substances is justified by the saving in

labor and material without impaii-ing the quality of the finished

product. Obviously, a still greater saving could be effected if the
196 EEPOET OF DIRECTOR OF BUREAU OF STANDARDS.

gj'psum itself could be so manufactured as to have the desired property without the addition of any foreign material. An investigation

into this matter has been productiA^e of the desired riesults. By a

slight and inexpensive change in the process of manufacture the

plasticity of gypsum can be increased so that it will spread easily

and carry a large amount of sand. A patent on the process of manufacture and on the product, " plastic gypsum," has been applied for

and dedicated to the free use of the public. Many companies are

installing the equipment necessary to make this material, and one has

already put it on the market.

Action of Retarders on Gypsum.

Pure calcined gypsum when mixed with water will set in 5 or

10 minutes. This is too rapid for most work; it does not give time

to mold the mnterial into the desired form. A retarder is therefore

added, which delays the setting to from one-half to six hours, depending upon the purpose for which the material is to be used. " Commercial retarder," which is universally used, is a slaughterhouse

by-product of indefinite composition. From the standpoint of the

user of the gypsum this retarder may be criticized on several grounds

Since it is of an indefinite composition, its action can hardly be

expected to be uniform at all times; it is rather expensive, and a cheaper material might be found; it slows down the rate of set,

instead of delaying the beginning of set, and in some cases the latter

effect is desirable ; it seems to prevent the hydration of some of the

calcined gypsum, thereby causing a slight reduction in strength.

To answer these criticisms an effort has been made to discover a new material which may be used as a retarder. To date this effort

has not been successful, although all of the criticisms have been met

except the one of cost. Adhesion Betw^een Gypsum and Cement.

How to make gypsum plaster adhere to a concrete wall is a question

which has puzzled many building contractors. Experience has

taught them how to overcome the difficulty, but they are still in the

dark as to why certain precautions ai-e necessary. Another phase of

the same problem is the use of gypsum mortar pointed with cement

for exterior masonry walls. To throw more light on these questions, a study is being made of the chemical reaction between gypsum

and cement and of the differential expansion of concrete and gypsum

plaster.

Effect of Temperature of Calcination on the Properties of Calcined

Gypsum.

The most important step in the manufacture of a gypsum plaster

is the calcination of the gypsum. The effect of the temperature of

calcination on the chemical composition of the product is well

established, but little is known about its effect on the physical properties. Moreover, the presence of impurities may be expected to

modify the effect produced by any given temperature. The question

is being investigated by calcining natural gypsum rocks at different

temperatures and measuring the chemical and physical properties

of the resultant products.
REPORT OF DIRECTOR OF BUREAtT OF STANDARDS. 197

Acoustics of Wall Plasters.

This research was started last year by this section and the sound

section of the Engineering Physics Division. During this fiscal year

the status of the work was such that only the latter section could

carry on the work.

Colored Plaster.

A new method for making colored plaster was described in the

last Annual Report. It consists briefly in introducing dyed wood

fiber into the finish coat of plaster and exposing the fiber by suitable treatment of the surface. The Bureau's publication on this

subject has attracted considerable attention, which was further augmented by an exhibit of samjjles in the booth of the ISTational Lime

Association at the own your home show in New York. Progress is delayed temporarily^ by the inabilit}?^ to connect with anyone who will

manufacture the dyed fiber on a commercial scale.

Measurement of the Color of Plaster.

Because of a rapidly growing demand from architects that wall

plaster should not be white, but should rather be of such a color

as will fit in with the architectural scheme, a means of specifying

the color of a plaster is rapidly changing from academic to economic

importance. A method for measuring the color of an opaque material had alread}^ been developed by the Optics Division of this

Bureau, and the adaptation of this method to make it applicable

to wall plasters offered little difficulty. While the method of

making the measurement is rather cumbersome, the results constitute a decided step in advance. It is now possible to specify the

color of a plaster in terms which are definite, clear, and unambiguous.

Specifications for Plastering Sand.

Sand is the major ingredient in all plasters. It seems logical, therefore, that if specifications for the minor ingredients, such as lime

or gypsum, are economically justified, surely there should be a specification for sand. On the other hand, sand is a cheap material, which

is found locally almost everywhere. It is generally better economy to use a local sand, even of known inferiority, rather than pay the

freight to bring in better material. However, experienced plasterers are able to recognize good and poor sands. This knoAviedge has

never been definite!}' expressed in writing, yet the Bureau feels that

it should be made available to the general public. Fifty-three sands

from widely scattered localities have been received for investigation.

Besides the sieving analyses, the plasticities and tensile strengths of

mortars made of these sands and lime, gypsum, or cement have been

measured. Other physical properties of these mortars are now being

studied.

Effect of the Grading of Sand on the Properties of Sand-Lime Brick.

An investigation conducted by this Bureau some years ago showed

that a brick of maximum compressive strength can be made of a mixture of coarse and fine sands in definite proportions. The standard

specificatiors for building brick include requirements for transverse

strength and absorption, as well as for compressive strength. It

therefore became desirable to know what effect the grading of sand
198 EEPOBT OF DIRECTOR OF BUREAU OF STANDARDS.

would have on these two properties. Briefly, the results indicate that

the finer the saiid the higher the transverse strength and the higher

the absorption.

Lime-Water-Glass Paint.

From tests made by the Chemistry Division of this Bureau it seems

possible to develop) a good paint by the proper application of whitewash and water glass. This matter has been taken up with the

National Lime Association and one of the manufacturers of water

glass. 8ome experimental work has been done, but the Bureau has

not as yet taken an active part in it.

Tests.

Three of the tests conducted during the year were in the nature of

research work, but were made at the request and largely at the ex- pense of private individuals. They were undertaken because they

gave the Bureau collateral information, which, however, was not of

sufficient scope to warrant separate publication. These three tests

were : The measurement of the contraction and expansion of a gypsum block partition, the utilization of waste plaster molds from the

terra-cotta industry, and the measurement of plasticities of magnesite stuccoes and flooring compositions.

During the fiscal year this section has made routine tests on 17

samples of lime and 5 samples of gypsum for other branches of the

Government, and on 79 samples of lime, 21 samples of gypsum, and

10 samples of sand-lime brick for private individuals.

Cooperation.

This section has cooperated with the brick, lime, and gypsum committees of the American Society for Testing Materials. Each of these

committees have prepared one or more specifications during the past

year. The specifications for materials used in jjlastering have been

formulated by the Bureau of Standards plastering conference, a body

composed of representatives of national associations interested in

wall plastering, organized by the Bureau in January, 1920. Tentative specifications for lime used in the manufacture of glass, caustic

soda, sulphide pulp, and leather have been prepared by the interdepartmental conference on chemical lime. This body is composed of

representatives from the various Government departments. Very

active cooperation is maintained with the National I^ime Association

and the Gypsum Industries Association, both of which maintain fellowships at this Bureau. The Sand-Linie Brick Association, through

its standing committee on standards, is in close touch with this sec- tion of the Bureau.

Publications.

During the past year the following papers, emanating from this

section, have been published by the Bureau

Technologic Paper No. 169, The measurement of plasticity of mortars and plas- ters (W. E. Eniley).

Teclmologic Paper No. 181, Colored wall plaster (W. E. Emley and C. F. Faxon).

Circular No. 106—Lime : Definitions and specifications.

Circular No. 108—Gypsum : Definitions and specifications.

Circular No. 109.—Sand-lime brick : Definitions and specifications.
BEPORT OF DIRECTOR OF BUREAU OF STANDARDS. 199

The following papers were published in the technical press, as noted

Effect of the duration of hardening on the properties of sand-lime bricli (W. E.

• Emley and W. M. Cleare), Proceedings Sand-Lime Bricli Association, 1920,

p. 17. How bricls piers fail (W. E. Emley and W. M. Cleare), Proceedings Sand-Lime

Brick Association, 1920, p. 57. Durability of sand-lime brick (W. M. Cleare), Proceedings Sand-Lime Brick

Association, 1920, p. 37. Use of lime in construction (W. E. Emley), Rock Products and Building Materials, .July 3, 1920, p. 65. The popping of lime plaster (W. E. Emley and C. H. Bacon), Jour. Amer.

Ceramic Soc, November, 1920.

Results of testing gypsum products (W. E. Emley and C. F. Faxon), Jour. Amer. Ceramic Soc, December, 1920.

Normal consistency of sanded gypsum plaster (W. E. Emley and C. F. Faxon),

Jour. Amer. Ceramic Soc, February, 1921.

Elfect of fineness on other properties of calcined gypsum (W. E. Emley and

F. C. Welch), Jour, Amer. Ceramic Soc, April, 1921.

Plastic gypsum plaster (W. E. Emley), Chem. and Met. Eng., April 27, 1921;

Rock products and building materials. May 14, 1921 ; Engineering NewsRecord, June 16, 1921.

Specifications for color of gypsum plaster (W. E. Emley and C. F. Faxon),

Chem. and Met. Eng., June 15, 1921.

RUBBER.

The greater part of the Bureau's work in rubber during the past

year has been devoted to the development of standard specifications

for materials purchased by the various Government departments.

This has involved a large amount of expei*imental work and a great

many routine tests and analyses. The results obtained have also

served the purpose of perfecting the Bureau's methods of procedure

in conducting physical and chemical tests. New Equipment.

There was installed during the past year a new vulcanizing press

equipped with automatic time and temperature control apparatus

which regulates the temperature within 1° F. An automatic pump

was installed for the operation of the vulcanizing presses. The

Bureau's experimental rubber laboratory is now equipped with all

the necessary machinery for compounding and vulcanizing in con- nection with research work on the properties of rubber and compounding ingredients.

Rubber Tubing.

Commercial rubber tubing used at the Bureau was not giving satisfactory service, and for this reason a number of different types of

-experimental tubing were made in the rubber section and placed in

service in the various laboratories of the Bureau with a view to developing specifications for such material.

T^ubber Jar Rings for Canning.

The Bureau has continued its investigation of jar rings in cooperation with the States Eelations Service, Department of Agriculture.

The object of this work is to determine the aging qualities of jar

rings in use or in storage and to revise the existing specification by

the inclusion of an accelerated aging test.
200 REPORT OF DIRECTOR OF BUREAU (lE STANDARDS.

Power Losses in Automobile Tires.

The Bureau has undertaken a general investigation of automobile tires and inner tubes, and in connection with this work a rather

comprehensive program has been laid out for dynamometer tests to

study, among other things, the poAver losses or energy dissipated into

heat in various sizes of cord and fabric tires, operated under different

conditions of axle load, inflation pressure, speed, temperature, and

tractive etfort. Preliminary tests have been made to determine the

influence of these factors which, aside from matters of design, are the

principal items affecting the power loss in a tire. A continuation of

the work will involve problems of design and construction, the influ- ence of " oversize " tires, and of cord tires on power losses, mileage,

and general efficiency of operation. An investigation will be made of

inflation pressures as affecting the efficiency and economy of tire

operation. Tests will be made to determine the effects of tire fillers,

shields, puncture-proof tubes, etc., and the properties of cushion

tires will be studied.

The dynamometers employed for this work, . a Ithough designed

primarily for investigational purposes, are adapted for routine test- ing to determine the relative durabilit}' of tires and inner tubes. It

has been suggested that a number of detailed requirements in the

existing Government specifications be eliminated and that a laboratory service test be substituted therefor. In working out a plan such

as this the results of dynamometer tests will be of great A^alue in designing a standard tire-testing machine and in interpreting the re- sults intelligently.

The Effects of Compounding Ingredients on Properties o£ Rubber.

The Bureau has planned an extensive investigation of the properties of rubber and the effect of compounding ingredients on the life

of the rubber under various conditions of use and storage. A studj

is being made of the properties of rubber and composition soles after

accelerated and normal aging.

Rubber Analysis.

An important part of the Bureau's work is the analysis of rubber

goods piirchased by the various Government departments. The long

list of ingredients mixed with rubber, is constantly being extended.

The properties of some of these ingredients are such that the usual

methods of analysis give incorrect results ; thus the existing methods

must be frequently added to or revised.

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 the use of suitable organic solvents

it is possible to remove the rubber and leave behind all the mineral

matter practically unchanged. This problem has been studied at

intervals during the past few years. Cymene has been found to give

very good results. In addition, the Bureau's general analytical

procedure was modified in many minor details, so as to save time

without loss of accuracy.

Miscellaneous Materials.

Under this heading are included not only a large number of rubber articles, such as hose of various kinds, belting, valves, packings, rubber-covered wire, jar rings, rubber bands, etc., but also many
REPORT OF DIRECTOR OF BUREAU OF STAJSTDARDS. 201

materials other than rubber. As typical examples of the latter may

be mentioned asbestos gaskets, canvas belting, linoleum, flax shot

lines used by the Coast Guard, sash cords, 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. The usual tests of miscellaneous materials were made for the General Supply Committee, the results

being used as a basis for the award of contracts covering the fiscal

j^ear 1921-22. Those Government offices which purchase on their own

specifications rather than from the General Supply Schedule utilize

the Bureau's laboratories to a large extent.

Cooperation with the Rubber Industry.

It is the Bureau's policy to coo^oerate to the fullest extent with

manufacturers, with the vieAv of having the requirements of specifications conform in every way to the best manufacturing practice.

When all available sources of information have been utilized, a

specification is prepared in tentative form and presented for discussion and final adoption at a conference of the United States interdepartmental committee on specification standardization. In this

way the requirements of a specification when approved are such as to insure a commercial product of satisfactory quality and well

adapted to meet the conditions of service imposed by the Government.

The following examples illustrate the service rendered the various

Government offices by the Bureau acting in an advisory capacity

The office of the Register of the Treasury reported difficulty in

the operation of canceling machines, resulting from the improper

functioning of certain rubber roils. The difficulty was overcome by

having a number of rolls possessing the necessarj?- properties made

in the Bureau's experimental laboratory. The Bureau made a great

many tests and analj^ses for the Chemical Warfare Service in con- nection with rubber gas-mask materials. The Bureau cooperated

with the Air Service of the War Department in perfecting the vari- ous requirements for miscellaneous rubber goods. Service was ren- dered the United States Shipping Board in the preparation of specifications for rubber hose and packings. The Bureau has been re- Cjuested to make periodical tests and analyses of samples furnished

by contractors on these specifications.

Specifications.

Automobile Tires and Inner Tubes.—The Bureau has been making

a study of automobile tires and inner tulles for the past few years.

As a result of this work specifications were prepared by this Bureau

and are now being used by the War Department, Navy Department, General Supply Committee, Post Office Department, Interior

Department, Panama Canal, Treasury Department, and Commissioners of the District of Columibia. These specifications in revised

form were recommended for adoption by the United States interdepartmental committee on tire specifications June 8, 1921, and will

be published as a Bureau circular. The specifications had been submitted fo the Rubber Association of America and to a large number

of tire ro.anufacturers, and in their revision careful consideration

was given to the recommendations received from these sources.
;202 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Ftre Hose—The specification originally drafted by the Bureau

has been revised in cooperation with the Rubber Association of

America. This standard specification in revised form, as officially

approved by the specification committee of the Rubber Association,

will be published as a Bureau circular.

Rubber Goods.—At the request of the General Supply Committee,

tentative specifications for rubber goods were drawn up by this

Bureau. All sources of information, such as investigations' made

at the Bureau and specifications now in use by other organizations,

were utilized in formulating these specifications, a list of which is given below : Cotton rubber-lined fire hose, general specification for

rubber goods, rubber bands, air hose, spray hose, steam hose, water

hose, rubber stoppers, rubber tubing, molded rubber ice bags, rubber bandages, rubber hot-water bottles, rubber ring cushions, rubber

adhesive plaster (zince oxide and plain), rubber dam, rubber sheeting for hospital service, rubber tips for crutches and hospital furniture, rubber rectal tubes, rubber stomach tubes, packing (sheet,

plain), packing (cloth-insertion), packing (wire-insertion), rubber

valves, rubber jar rings, rubber cement, and radiator hose.

Publications.

Circular 38, " Tlie testing of rubber goods," was revised and amplifled ; it is now in press. -An article, " Tlie determination of antimony in rubber goods," written by

members of the Bureau's staff, was published in Rubber Age and Tire News,

vol. 8, 1920; Rubber, Engineeriug Production, vol. 2, part 1, 1921; India

Rubber .Journal, vol. 15, 1920. An article, "An improved method for the determination of the total sulphur in

rubber goods," was published in Rubber Age and Tire News, vol. 9, part 2, 1921.

LEATHER.

This work is concerned with the investigation and testing of

leather and leather goods, to determine the physical and chemical

properties and relative durability of different kinds of leather upon

which to base standards of quality.

Sole Leather.

The investigation to determine the durability of leather tanned

and filled with vegetable tanning materials as compared with leather

tanned and filled with sulphite cellulose extract is nearly completed.

Eighteen hides were prepared for these tests by three tanneries.

Alternate sides of the different hides were filled with sulphite cellulose extract, while the remaining sides were filled with a mixture

of chestnut wood and quebracho extracts. The results obtained from

approximately 250 service tests on soles are as follows:

[Results expressed in day's wear per iron (unit of thickness equal approximately to one

forty-eighth of an inch).]

Lot No.

Vegetable

tanning

material

filler.

Sulphite

cellulose extract

filler.

1 8.0

7.2

7.6

6.5

7.5

7.4

7.8 6.4

23

4

7.5 7.3
REPORT OF DIKECTOR OF BUREAU OF STANDARDS. 203

From the results of these tests it can be stated that the sulphite

cellulose extract used in these tests as a filler for sole leather does

not materially affect its durability.

The results of 20 service tests made to compare the durability of

waterproofed and nonwaterproofed oak sole leather showed that the

-waterproofed soles outwore the nonwaterproofed soles by 2.7 per

cent. This difference is negligible, and the results tend to disprove

the contention that waterproof dressing a sole prior to its application to the shoe will increase its durability.

A series of tests made on the laboratory wearing machine with

'different samples of sole leather shoAved that the interior portions

of sole leather have a greater resistance to abrasion than either the

grain or the flesh sides. The results of these tests were published as Technologic Paper No. 166. It is of interest to note that a series

of tests of similar nature made by the British Boot, Shoe and

Allied Trades Research Association gave essentially the same results.

Upper Leather.

An investigation of the suitability of shark-skin leather for shoe

uppers is still in progress. Several pairs of shoes which have the

uppers of one shoe made with shark-skin leather and the other with

•calfskin leather are being subjected to actual service tests. From

observations made up to the present time it appears that the shark

leather is as durable as calf leather and has the advantage of not

scuffing or peeling. Hence, its impairment in appearance is less

rapid. The shark leather referred to is a

" grain split." and laboratory tests show that it has greater tensile and tearing strength than

calf leather.

A quantity of hogskin leather degreased in a vacuum chamber and

then chrome tanned is being made into shoes for an investigation of

the comparative durability of hogskin and calfskin uppers.

Membrane for Air-Speed Recorders.

The results of tests made to determine the suitability of leather

prepared from the colon of a cow for use as diaphragms in air-speed

indicators show that the leather is affected considerably by cold

temperatures. The effect is greater as the tautness of the leather is

increased. The leather is also porous to some extent. These facts

exclude the use of leather where the characteristics of the indicator

depend upon the elastic qualities of the leather. It is considered

that lightness and pliability of the colon leather would make it valuable for use in instruments Avhen the readings are independent

of elastic qualities of the leather.

Rabbit-Skin Leather.

Several samples of both domestic and Australian rabbit skins

were examined during the year. Ph3^sical tests showed that the

tensile strength of these leathers was low, averaging from 1,200 to

2,000 pounds per square inch, and that the tearing strength was

also low. Raw skins tanned in the laboratory gave the same results.

In general, the surface of the skins contained many defects which

would make the use of the full-grain leather unsatisfactory. Suede

and embossed finishes cover these defects, so as to make the leather

suitable for novelties. The use of rabbit skins for shoe uppers

would not be economical on account of tlie small size of the skins.
204 REPORT OF DIRECTOR, OF BUREAU OF STANDARDS.

Preservative for Shoes.

, An investigation of various leather preservatives for use on Army

shoes was made for the War Department. Of the dilferent samples

tested the one consisting of a mixture of sulphonated castor oil,

heat's-foot oil, and mineral oil appeared to be the most satisfactory.

Specifications.

At the request of the U. S. Public Health Service specifications

were prepared for calf art leather, sheepskin art leather, russet lining

leather (calf), sheepskin lining leather (skivers), cowhide tooling

leather, and calf tooling leather. A specification for black and russet

strap leather was prepared for the Panama Canal. A standard specification for vegetable tanned leather belting has been developed.

This specification has received the indorsement of the Association of

Leather Belting Ma nufacturers, and it will be published as a Bureau

circular.

Publications Issued.

Tech. Papei' 166, " Laboratory wearing tests to determine the relative wear

resistance of sole leather at different depths throughout the thickness of a

hide."

Routine Tests.

There were tested during the past year 166 samples, including harness leather, leather belting, ledger binding, straps, packing leather,

artificial leather, rawhide lace leather, sole leather, fishskin leather,

sheepslrin garment leather and bridle leathers.

TEXTILES.

General Facilities.

The section has for the past two years been concentrating on the

development and extension of its equipment in order to meet the wide

variety of demands made for information concerning the many

fibers, yarns, and fabrics used in the textile industry. Perhaps the one greatest advance which has been made is the establishing of a

testing room where the temperature and relative himiidity can be ac- curately controlled.

The installation of the laboratory cotton mill has been completed,

and experimental fabrics are being made when necessary in order to secure samples for experimental work. The section is now prepared

to take up problems relating to manufacturing and testing in practically all of its phases.

Specifications.

Specifications have been prepared for the War Department, Navy

Department, and the Panama Canal covering a wide variety of textile materials. In practically all cases it was necessary to conduct an

investigation to determine what properties were desired before specifications which would give these properties could be recommended.

The materials for which specifications were prepared and recom- mended include mattress ticking, cloth for Army insignia, elastic

webbing, tarred marline, cloth for musette bags, rubberized sateen,

webbing, street-sweepers' brooms, caulking cotton, flax and ramie

cord.
KEPOET OE DIRECTOR OF BUREAU OF STANDARDS. 205

•:.T^i 'J<: National Association of Dyers and Cleaners.

; , The National Association of Dyers and Cleaners have offered their

cooperation in the multitude of problems on the conservation of

textiles which are confronting the dyers and cleaners and which

should also receive the attention of the wearer or consumer. No

definite program has been outlined as yet, due tq the necessity of

" establishing a permanent cooperative organization, which is most

essential for the success of the project.

Cooperation with the National Association of Woolen Manufacturers.

Considerable work has been done for the National Association of

Woolen Manufacturers on problems submitted pertaining to the

maimfacture and the properties of their finished fabrics, together

with methods for measuring these properties. The problems submitted are yevy comprehensive and require considerable time. Laboratory requirements in the form of test methods and apparatus are now under way, and pleasing progress has been made. Renewed

efforts are now in progress to derive a program in order to arrive at

an earlier solution than was planned.

Annual Technical Textile Conference.

A new committee was formed this year from the leading technical

textile men in an attempt to broaden the scope of the work to be

taken up by the committee for these annual conferences and the

assistance to be given to the industry on technical matters. It was

the opinion of the committee that a permanent committee and con- ference with associations should be established. In taking up these

new plans the time necessary would not permit the annual May con- ference to be held, but such a conference will be held during the coming year.

Microscopy of Textiles.

Microscopic and photomicrographic methods are becoming of

greater importance and are being more generally employed than

ever before in the study of various problems arising in the manufacture and analysis of textile fabrics. This section has been able to

make a more thorough study and analysis of the properties of balloon

and airplane fabrics by means of photomicrographs of these materials than it otherwise could have done.

In the study of textile fibers and the analysis of fabrics for fiber

composition the microscope is indispensable and is becoming more

generally so regarded. In order to promote the intelligent and

systematic use of the microscope in this field, this section is preparing

a series of photomicrographs of the textile fibers, which are intended to show as clearly and distinctly as possible their physical

characteristics, such as relative length and diameters, markings,

thickness, and regularity of walls, shape of ends, etc. For this purpose, of course, the individual fibers are used and not a bundle of

fibers. 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.

The Bureau is constantly adding to its collection of authentic

samples with which comparisons of various fibers are made fcjr, iclen.-
206 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

tification. During the year the Bureau requested and was permitted

to gather a large number of fur and hair samples from the National

Museum and also obtained from the Zoological Park several samples

of hair from animals which have been domesticated in several foreign countries. The numerous additions to the collection of hair

fibers afforded an opportunity for comparisons in identifying fiber

contents of press cloths made up almost entirely of hair fibers.

Balloon Fabrics.

Investigations on experimental fabrics have been continued

throughout the year. Work on problems for the Aircraft Divisions

of the Army and Navy Departments has progressed, so that several

problems are finished while others will have to be continued in the

next fiscal year.

The problem on the effect of thread count on permeability has been

completed. Cloths varying from a high number of threads per

inch to a comparatively low number were woven by the Pierce Manufacturing Co. and made up into balloon fabrics by the Goodyear

Tire and Eubber Co. These fabrics were tested and then exposed

to the weather for 210 days, test samples being cut off at the end of

every 30 days. From these tests the deterioration of the fabrics

was followed until they had reached a point where they were of no

use as balloon fabrics. The results, while not so conclusive as it was hoped they would be, indicated that a fairly high thread count,

about 120 by 130, is necessary to secure the required strength and

life of the fabrics. Several interesting points were brought out which

will need further study before they can be accepted.

Exposure tes^s on 26 frames of balloon fabrics doped and coated

in various ways are now under way. Ten-day readings of the taut- ness of each frame are being taken in recording the loss to permanency of tautness, a property of resistance to deflection. The

instrument used in this investigation, which is being conducted in an

endeavor to find a substitute for the present goldbeater skin fabric,

was developed and designed in the textile section.

Assistance was also given to the Army Balloon Service in testing a large number of representative specimens of balloon cloth which

were in storage and the most of which were to be sold as surplus.

Over 2,000,000 yards were to be sold, while the best cloths were to

be retained.

A short article was completed on the bursting of balloon fabrics, a

test which in theory was to represent the actual conditions of a

fabric in service.

An interesting problem in connection with the bursting test used

on balloon fabrics at the Bureau for the last several years has been

presented. The balloon-bursting test which is used to determine the

stresses and strains of a particular kind of fabi'ic of given size and

shape under gas pressure has proved invaluable in this field. The

problem of ascertaining whether and for what length of time a

fabric would hold up after a small hole, such as a bullet might make,

has been made in the covering, resulted in a s*^iidy of the effect of size,

shape, and orientation of a hole with respect to the systems of threads

on the resistance of the fabric to tear. From the results of this investigation a standard tear test was evolved.
KEPOBT OF DIRECTOE OF BUREAU OF STANDARDS. 207

Length Tolerance of Blankets.

An interesting problem was presented to this section by the blanket

trade. It was desired to find out what factors entered into a very

marked variance in the length of blankets and to what extent the

manufacturer was responsible for these changes. This was not only

subjecting them to loss through breach of contract suits, but in their

endeavor to overcome their difficulties the blanket company was adding several inches to the normal length, so that the blanket might be

longer rather than shorter than the stated length.

This was taken up in two phases. The first, a laboratory investigation, studied the effect of humidity on the length of a finished

blanket, using four of their regular types. The second was a study

of the effects of manufacturing processes and conditions. This latter

part is still in progress. Members of the Bureau's staff went to the,

mills and after a brief preliminary survey mapped out a program

which will probably give the necessary data for solving the problem..

These data are being collected by representatives of the mills.

This investigation is considered a very valuable one for this.

Bureau. It was taken up, first, because it was thought it might,

prove to be the entering wedge in demonstrating the result of scientific consideration of mill problems on the quality of the product. It

is also giving this section some very valuable data in regard to mill

conditions as affecting quality in general. The results of this investigation will be sent to each of the blanket manufacturers for the

purpose of having inserted in future contracts a statement regardinglength and conditions affecting it, so that any further litigation may

be avoided.

Utilization of Low-Grade Cottons.

Preliminary work has been started in an endeavor to collect some

data on the important problem of the utilization of low-grade cotton.

Those interested appear to be very willing to cooperate in this investigation, and considerable work can be done to assist the grower to

dispose of his material, which at this time has little or no market.

This would result in the designing of cheaper fabrics, thus lessening

the cost of living. No definite program has been outlined, but it is

hoped that conditions will permit the undertaking of considerable

work this coming year.

Cloth Variables Investigation.

In the manufacture of cloth there are a great many variables due

to machine design and construction of the cloth, all of which have

some effect on the quality and strength. Heretofore most of these ^ variables have been disregarded, resulting in a lack of uniformity

in the product of a mill and making it very difficult for two mills

to produce a like product.

The study of the effect of these variables on the properties of the

finished cloth is very involved, and until recently the Bureau was

not in a position to take up this problem. Now that the section has

a small experimental cotton mill, where these variables can be controlled, the problem has been taken up. As a starting point it was .. decided to take samples of cloth similar in many respects and by-
208, KEPOBT OF DIRECTOR OF BUREAU OF STANDARDS.

changing one variable at a time determine the effect on the properties of the cloth. Samples have been made, and the effect of crimp,

twist in the sing-Jes and ply yarns, and threads per inch is now being

determined. This problem will probably extend over a period of

years, but the results will be of value as they are obtained and need

not necessarily wait on the completion of the investigation.

Filter Press Cloths.

The problem of a standard oil percentage and moisture regain

for press cloths was brought to the Bureau's attention by the users of press cloths, who presented it with the purpose of haAdng a fixed

basis for transactions between manufacturer and user to eliminate

arguments and litigation in the buying of press cloths.

A number of samples were analyzed, and the results are being

studied to accomjolish the desired results. It is planned to submit a preliminary report to a committee of users and manufacturers and

have them render an opinion in regard to the conclusions to be

drawn. This seems to be the best method of handling a problem

such as this, for. it is realized that any findings that the Bureau

would submit to the trade might be rejected by either one side or the

other. This committee, which includes the principal users and manufacturers of press cloth, will give such findings as are agreed upon

more authority.

Properties of Cotton Fibers of Different States of Maturity.

A preliminary program was outlined to study the spinning possibilities and physical properties of cotton fibers before and after

they have fully matured. Microscopic examination shows that a cotton fiber has a different cell construction before it is wholly

ripe, and for this reason there has been a demand by the industry

for information concerning the relative value of the fiber in this

state as to its manufacturing possibility and performance. Results

of this work should be of great assistance in the attempt to shorten

the picking season, which lasts over a period of three or four months.

One of the benefits to be derived from this investigation would be

that the materials could be classified according to their spinning possibilities and performances, giving the manufacturer a definite commodity for his needs. The results could also be incorporated with

the effect of patent processes for chemical ripening of cotton. Due

to the lack of cooperation, no great progress was made, and the

investigation was confined to a preliminary outline which proposed

the formation of a committee of growers and harvesters for the

carrying on of the outside work.

Suitability of Paper and Cotton Bags in Relation to Burlap Sandbags.

In cooperation with the paper section of this Bureau work on the

study of the requirements of sindbags in trench and barricade

warfare was completed during the year. The study has special

reference to the cost, availability, methods of manufactui"e, durability in transportation and handling under all conditions of

weather and location for a period of predetermined life. The work

was undertaken at the request of the ranging and camouflage unit

of the War Department, who are conducting the actual service tests,
KEPOET OF DIRECTOR OF BUREAU OF STANDARDS. 209

"which as yet have not been reported. A final report under this

heading lia,s been compiled for the laboratory work.

Florida or Spanish Moss.

At the request of the W&r Department an investigation of the,

properties of Florida or Spanish moss was carried out to determine

its suitability as a mattress filler in place of hair or cotton. It was

found that when properlj^ used the moss was inferior to hair, but

was more satisfactory than cotton.

Numbered Cotton Ducks.

Through cooperation with several manufacturers of numbered or wide ducks, who furnish all of the material, a study of most of the

commercial ducks of this class was made to find out what constructions gave the greatest strength and what variations occur between

the same number of duck in the different makes. The results will

be used in preparing specifications Avhich will be recommended in

place of the existing specifications, which have proven to be unsatisfactory.

Testing of Cotton Ducks.

In conjunction with a large private textile laboratory a series ol

tests was made to detei'mine the effect of different shapes and sizes

of the test specimen on the indicated strength of duck. All of the

ordinary methods of test and several new methods were tried out

with very interesting results. It was found that each method of

test and each different shape of specimen introduced a variable, the

value of which would l^e difficult to determine except in the case of the strip method of test. The correction factor for the error

in the strip method of test can be readily determined, but for

ordinary testing can be disregarded, as the correction factor is lesji

than the variation between the individual test specimens.

Artificial Silk.

Eepresentatives of a fiber silk company used the facilities of

the bureau's testing room to run a number of tests on strength,

elasticitj^, twist, and weight of samples made at their plant for

the purpose of improving the product, if possible, in accordance

with the results obtained. The Bureau views such projects with

satisfaction, since they show that the industry is applying scientific

methods more and more in the working out of their problems and

the improvement of tlieir products.

Investigation on Waste Silk Materials.

The Bureau was asked by the Ordnance Salvage Board of the

War Depailment to determine the possibilit}' of spinning into commercial spun-silk yarns a large quantity of waste silk which was

purchased to be spun into yarn for cartridge bags.' -A representative went to the Army base depot where the material was stored and

outlined the work necessary. Boiling-off tests were made at Philadelphia in cooperation with a spun-silk manufacturer. The final

report to' the Ordnance Salvage Board contained a complete classification of waste silk used in commercial spun-silk yarns and the

64984—21 14
210 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

amount of commercial yarn that could be obtained from each tyi^e of

waste and also a complete set of photographs of both the commercial

wastes and the Ordnance Salvage Board wastes for visual comparison.

Chemical Retting of Flax.

Assistance was given to a new project for the chemical retting of

flax for use in manufacturing linen yarns. Physical tests were made

to determine whether or not the rapid chemical action has any detrimental effect on the strength of the fibers. Several numbers of

yarns were tested and also a number of samples of woven fabric.

This work was done in conjunction with exhaustive and expensive

experiments by private parties in an attem.pt to develop the linen

industry in America and which will probably continue for some

time in the future. The Bureau is glad to offer any assistance possible in the furthering of this industry.

Pompier Belts.

The fire department of the District of Columbia experienced some

difficulty in the buying of pompier belts in specifying just what loads

and what service a belt of this nature should reasonably be called

upon to furnish. A study was made of the properties of the belts

now in use, and I'ecommendations were made for several changes.

The Bureau also took up the subject of certain periodic service tests

on these belts and tests on life nets.

Asbestos Brake Linings.

Samples of abestos brake linings were submitted for test to determine their suitabilitj^ for the purpose intended. The percentage of

asbestos and other materials was obtained, the ability of the samples

to absorb water and oil and to permit ready evaporation was determined, and the results compared in the varioizs samples.

Conveyor Belts.

In conjunction with the Post Office Department the Bureau is

collecting data preliminary to writing specifications for conveyor

belting for use in post offices. The Bureau is conducting the laboratory tests and outlining the service tests, while the Post Office

Department is furnishing the belting and is carrjdng out the service

tests. Test belts made up of segments of several types of belt are now in use, and it is expected that at the end of 18 months the belts

will have shown enough depreciation to be taken out. The laboratory tests are nearing completion and will be checked against the

service tests as rapidly as possible.

Umbrella Cloths.

Some work was done on the possibility of replacing the highpriced umbrella cloths with cheaper fabric, such as balloon fabric.

Physical tests were made for comparative purposes, and the results

showed that the balloon fabric was superior in most cases. The*e

were a few essential requirements which were lacking but which

could be corrected in the original design. This short investigation

brought out the desirability of a study of the properties of a material

according to its particular use.
REPORT OP DIRECTOR OF BUREAU OP STAISTDARDS. 211

Cloth-Measuring Tapes.

Cloth-measuring tapes are usually made from flax or hemp with

or without metal threads, which aid in keeping the tape unelastic.

In an endeavor to produce a satisfactory cotton tape special yarns

were secured and are now being woven at one of the mills. The preliminary results would indicate that a satisfactory tape can be made

of cotton, but further tests must be made before any conclusions, can

be drawn.

Printer's Blankets.

An investigation of the printer's blankets used at the Bureau of

Engraving and Printing has been undertaken because of the diffi- culty which has been experienced by the Government in purchasing

satisfactory blankets. The results of this investigation will be used

in preparing specifications which will insure a blanket which will

meet the requirements and which can be duplicated when necessary.

Routine Testing.

Over 5.500 samples were tested during the past year, principally

from Government departments and organizations, of which the

Panama Canal, War Department, Navy Department, and Post Office

Department were the chief contributors. The tests coA'ered 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. While most of the tests used to estimate

the value of the Government's purchases in textiles, especially the

checking of samples to the specifications under which they were

bought, are of a routine nature, their importance in almost all of the

Bureau's research problems has been realized. The majoritj^ of the

researches are helped materially by additional data furnished by the

routine testing, and, considering the nmnber of samples which have

been tested and the care and accurac}^ necessary in their preparation,

it is very evident that routine testing occupies an important place in

textile laboratory work.

Information.

One of the Bureau's activities has been to prepare and furnish information on scientific and technical subjects pertaining: to textile

mill and laboratory equipment and also to aid in standardizing specifications and performances of textile materials. It is the tendency

of the textile industry to increase their efforts toward the adoption

of scientific methods and research in the improvement of their products. Consequently, demands on this section have been multiplied for

solution of technical problems and for information.

Cooperation with Societies and Textile Organizations.

Members of the textile section have cooperated with the following

Societies : National Research Council, American Society for Testing

Material, Am.erican Society of Mechanical Engineers, National Advisory Committee for Aeronautics, National Association of Woolen

Manufacturers, National Association of Cotton Manufacturers, National Association of Wool Growers, National Association of Dyers

and Cleaners, Cotton Duck Association, Oklahoma Cotton Growers'

Association, and Interstate Cotton-Seed Crushers Association.
212 r.EPORT OF DIRECTOE OF BUREAU OF STANDARDS.

Publications.

No extensive publications were made during the past year because

of the time required for solution of problems under way. Plans have

been made for a series of publications for the coming year.

PAPER.

General Conditions.

Practically all the equipment purchased last year has been set up

and is in operation. The addition of this equipment to the paper

mill—300-pound beater with suitable chests, supercalender stack,

sheet cutter with \a.j boy, four-plat flat screen, and additional motors—has made it possible to work more efficiently. The methods of

obtaining and tabulating data in the i^aper mill have been sj^stematized and a much hirger amount of data is now being obtained. The

constant temperature and humidity room has made it possible for

all physical tests to be of greater accuracy than ever before, and the

equipment has been adjusted and changed somewhat to produce

greater uniformity of conditions.

Stain for Sulphate Pulp in Paper.

Kraft paper may or may not be made of so-called " Kraft " or sulphate pulp, and it is someAvhat difficult to determine whether such

paper is produced by using sulphate or sulphite wood pulp. The development of a method for this purpose has been completed and the

data published (Bureau of Standards Technologic Paper 189).

The fact that a suitable mixture of two dyes (malachite green and

basic fuchsine) stains the two pulps differently is used as a basis for

differentiating between the two pulps. The selective stain colors sulphate pulp blue or blue-green, and unbleached sulphite pulp is colored

purple or lavender. It is therefore possible to estimate the relative

proportions of the two fibers when present. The procedure consists

of disintegrating the sample of paper by chemical and mechanical

means, so that the fibers are separated. A small group of these fibers are then placed on a microscope slide and treated with the prepared

stain under cextain conditions. When properly prepared, the sulphate and unbleached sulphite are easily distinguished under the

microscope, and by use of standard snmples it is possible to estimate

the proportions of the two kinds of fibers. The chief difficulty in the

past has been that similar species of wood are used in the production

of both kinds of pulp, and it is therefore necessary to produce some

distinctive color, as the fibers have much the same shape and

markings.

Condenser Paper.

Manufacturers of electrical instruments have found it difficult to

obtain paper suitable for use in electrical condensers. The two important qualities of a paper for this purpose are that it should be relatively thin (0.0005 inch) and free from conducting particles. Commercial mills are able to produce paper of this thiclmess, but find it difficult to keep out the conducting particles. A series of runs were

made using raw " shirt cuts " and linen rags. Beater rolls with iron

or phosphor bronze bars were found to be unsatisfactory for this pur-
EEPOET OF DIKECTOB OF BUREAU OF STANDARDS. 213

pose, as the paper contained a large number of conducting particles.

A special composition roll (concrete and flint) was tried and found

to give much better results. Difficulty was experienced with the

Fourdrinier machine in obtaining a paper of suitable thickness,

although paper was obtained of about 0.0008 inch in thickness and

having about two conducting particles per square foot. A special

attachment will be obtained for the paper machine to make it possible to produce paper of the required thickness. The conclusions

drawn from this work are that this paper should be made of new

" cuttings," carefully dusted and sorted after cutting, washed, and

beaten with stone or composition roll and on a Fourdrinier machine

with pick-up felt attachment to carry the web from the couch to the

drj'ers. Extreme care must be exercised to keep all dirt and metal

from the stock during the process, and clean, new stock should be.

used.

Sizing Quality of Paper.

Certain materials, such as rosin, starch, glue, etc., are added to

paper to make its surface suitable for writing and printing purposes.

This quality is called sizing, and the methods in general use of

determining this quality of paper are unsatisfactory. The development of a satisfactory method is very desirable, especially as a means

of studying the effect of sizing materials in the manufacturing process. Considerable progress has been made since last year along this

line, but it has been found that the large number of factors which influence the electrical conductivity method make it very difficult of interpretation. A different kind of method has been investigated, and

it is thought that this latter method will not only give values for the

sizing quality of paper but will permit of interpretation of the curves obtained by the conductivity method. The development of a method

for obtaining a numerical value for the sizing quality of paper will

make it possible to define this quality in specifications, to produce

more uniformly sized paper during manufacture, and to investigate

the effect of different sizing materials, their efficiency, and the effect

of the whole manufacturing process (especially beating and drying)

upon the sizing quality of paper.

Paper Testing.

Due to the large nimiber of requests, a circular (No. 107) on " The

Testing of Paper" was prepared. This circular contains information relating to the methods of testing and the apparatus emplo^-ed

in the paper laboratories of the Bureau of Standards for the routine

testing of ])aper. In the introduction a brief description of the raw

materials used, the size and importance of the pai^er industry, and

the general groups or classes of paper are given. The classification

of paper is only of a general nature. The purpose of such tests and the developm^ent of methods of testing is touched upon and suggestions are given as to the methods of developing specifications.

The testing of paper is divided into three groups, and the methods

are classed as physical, chemical, and microscopical. Under each

group the various standard methods are given in detail, with photographs of apparatus employed. No attem.pt is made in this circular

to interpret results of tests. It is brought out that changes of tern-
214 REPORT OF DIRECTOR OF BUREAU OF STAN-DARDS.

perature and humidity affect the physical qualities of paper, and

for this reason a constant temperature and humiditj^ room has been

installed. It has not been possible to give the relation between

humidity and temperature changes and the physical characteristics

of paper, but it is hoped to have this information available later.

The chemical testing of paper is concerned with the determination

of the amount and kind of filler or loading material used and the

amount and kind of sizing in the paper, and both qualitative and

quantitative methods are given in some detail. It is desirable to

know the kinds of fibrous materials out of which a sheet of paper is made, and for this purpose certain stains are used to color the fibers

on a microscopical slide. The procedure is given and suggestions

are made as to the value of microphotographs. A short working

bibliography is included, as well as regulations for tests and methods

of sampling and submission of samples for test. Paper Bags for Lime and Cement.

The development of suitable methods for testing paper bags for

lime and cement was continued from last year, and the data obtained

have been published (Bureau of Standards Technologic Paper No.

187). This paper contains information relating to the methods of

testing and the apparatus employed in determining the quality of

paper bags for lime and cement. A brief description is given of

the ordinary tests performed on paper, such as weight, in pounds,

of the standard-size ream, 25 by 40—500, bursting strength in points,

tensile strength in kilograms, stretch in centimeters, folding endurance in number of double folds, percentage of fiber composition,

percentage of ash, and percentage of rosin sizing. A special test is

developed for giving numerically the stresses and strains that the

paper of these bags undergo in service. This test is called a resiliency or endurance test. A service test is also given to determine the breaking strength of the paper Avhen the bags are filled and dropped. A

comparison is made of the results of this test with the results of the

above resilienc}^ test. Another service test is developed for determining the strength of the adhesives used in these bags. The results of

all these tests are tabulated, and from these data the very best quality bags are chosen. In the conclusions special consideration is

given the choice of best bags in determining the characteristics of

a good quality bag, and specifications are drawn up accordingly.

Paper and Cotton Bags for Use as Sandbags.

On September 6, 1919, a request was made by the Corps of Engineers, War Department, for information from the Bureau of Standards in regard to the development of a substitute for the jute fiber

used in the manufacture of sandbags and burlap. Since the raw

material is not found in this country and as the manufacturing of

jute fabric is carried on abroad it seemed desirable that a material

should be available which could be obtained at all times in the United

States. A superficial survey indicated that either woven-paper

fabric or crinkled solid paper were promising materials for this

purpose, but that commercial manufacturers had done little experimental or development work along this line. Since the paper section

of the Bureau of Standards was at that time conducting an investiga-
REPORT OF DIRECTOR OF BUREAU OF STANDARDS, 215

tion on paper bags for lime and cement, and for that reason was in a

position to undertake an investigation into a material for use in

sandbags, the Chief of Engineers placed a formal request with the

Bureau of Standards to carry on the above investigation. A confer- ence was then held between the officer representing the War Department and representatives of the paper and textiles section. Bureau

of Standards. In this conference it was decided that representative

samples of paper, cotton, and burlap should be obtained from the

manufacturers. The investigation was carried on jointly by the

paper and textile sections.

All tests in this investigation, with the exception of tests on wet

material, give results which indicate that paper 16730, a rope paper,

would be a very good substitute for burlap. This paper, however,

is very weak when it becomes wet. If this paper could be waterproofed this difficulty would be eliminated, but the waterproofing of

paper at the present time is in the experimental stage. Many formulae for waterproofing have been patented, but when they are tried

out in the paper mills it is found that they either do not waterproof

at all or destroy the suitability of the paper for the purpose for

which it is to be used. Practically all the work on waterproofing to

date has dealt only with the chemical treatment of the fiber either

before or after the paper has been made, while very little work has

been done on the scientific control of the beating process in the manufacture of the paper. It is planned by the paper section to investigate this problem thoroughly and by the use of chemicals along with

the scientific control of the beating to manufacture, if possible, a paper similar to paper 16730 and yet waterproofed sufficiently to

make it suitable in every respect for sandbags. Since paper 16730

contains 30 per cent manila and jute rope stock, which might be hard

to obtain in time of war, since the jute raw material is not under

United States control, it is probable that the paper section will also

undertake to manufacture a 100 j)er cent sulphate fiber paper that

will be as strong as the above rope paper.

Waterproofing of Paper.

In connection with the investigation of a paper bag suitable for use as a sandbag, it was found necessary to develop a paper that

would retain a reasonable strength when wet. The method of determining this quality was to compare the results obtained by test- ing the paper when dry and after soaking in water for one hour.

It was felt that an increase in the amount of rosin sizing added to

the beater would increase the wet strength of the paper. A series of runs was made, using different percentages of rosin and maintaining

the other factors as nearly constant as possible. It was found that

the addition of 6 per cent of rosin increased the wet strength to a

ratio of about one to four, whereas the ratio in the case of commercial papers tested for this purpose was one to twelve or fifteen. The

increase of wet strength seems to indicate the advisability of con- tinuing this work. A sufficient quantity of this paper should be

manufactured, made up into bags, and given practical tests. Tearing Strength of Paper.

As indicated in the previous annual report, the development of

a method suitable for determining the tearing strength of paper is

very desirable. This work was continued during the year and an-
216 KEPOBT OF DIEECTOK OF BUKEAU OF STANDARDS.

other type of instrument has been investigated. The results of all

this work will shortly appear in publications of this Bureau. Aside

from the mechanical features of the machines themselves, it has been

found that this test is affected by the rubbing of the sample during

the tear when more than one ply is used, and also that the width of

the sample affects the test. This latter is probably due to the assist- ance given by the fibers adjoining those being torn and seems to ex- tend out from the place of the tear. Although most of the instruments sold for this purpose are satisfactory for certain work, it is

thought that the two factors mentioned above must be considered

before a really accurate machine will be available.

Newsprint.

The possibility of using sulphate pulp in place of sulphite pulp

in the manufacture of newsprint was investigated. Various combinations of ground Ivood, news sulphite, and sulphate pulps were

made into neAvsprint. Small batches were run anci the results were

not very conclusive, especially due to the fact that the machine could

not be run over 75 feet a minute, while newsprint is normally manufactured at from 600 to 1.000 feet a minute. However, as far as the

tests made were concerned and not taking into account the slow speed

of the machine, it was not thought objectionable to use sulphate pulp

for newsprint.

Testing of Blotting Paper.

The method of testing the absorbent quality of blotting paper

generally in use in the Government service is not satisfactory, as it

does not take into consideration the thickness or cross area of the

sample being tested. A study has been completed on several methods;

of determining this quality, and the data will be published in the

near future. The addition of clay to the " furnish " for blotting

paper generally produces a paper with a relatively high absorbent

quality, but such a paper will not be very satisfactory for repeated

blottings on the same spot. It is thought that this factor must be

considered in the development of specifications for this grade of

paper.

Carbon Paper,

With the cooperation of the Chemistry Division an investigation

of methods of testing carbon paper has been undertaken. Not only

are various grades of base tissue ixsed and man^^ kinds of coatings

but there are few reliable methods for determining the quality and

efficiency of carbon paper. Practical life tests by typists are not

alwa3'S possible, and the analysis of the coating is of little value.

In addition to this, different kinds of carbon paper should be used

for different work and different weight paper should be used in con- nection with carbon paper for various uses. The life of a sheet of

carbon paper is important, as well as the number of manifold copies

a certain grade will make. The assistance and cooperation of the

manufacturers has been obtained, and it is hoped that the whole

question of carbon paper may be put on a more technical basis.

Testing and Information.

Routine Testing.—A suitable personnel is maintained to handle

the large number of samples of jDaper submitted by the Government

and the public for test. This work is well standardized, and nearly
EEPOET OF DIEECTOB OF BUEEATJ OF STANDAEDS. 217

all samples are reported within a week of receipt. It is difficult in

most cases to obtain suitable samples for test, and this applies to a large number of the Government bureaus. Emphasis has been laid

on the necessity for proper sam^pling, which is as important as the

testing. Below is given a statement of tests during the fiscal year

' Number of samples.

Government Printing Office 2, 3S1

General Supply Committee f 363

Post Office Department 173

Panama Canal 89

Department of Commerce 76

Department of Agriculture 72

United States Shipping Board 45

Navy Department 26

Treasury Department 22

War Department 14

State governments 8

Bureau of Engraving and Printing 2

Miscellaneous 86

Bureau of Standards 656

Total for the Government 3,963

Total for the public 298

Grand total 4, 261

Information.—A large amount of information is given to the general public and to the Government through correspondence and to

individual visitors. It is iinpossible to estimate the time spent in this

connection. A sl>ort list of -some of the more important subjects

covered is given below

The increase in the quantity of cotton linters used for paper

mamifacture has been reflected in the increase in the number of

requests for information about them. Second-cut linters, when kept

clean and jDroperly prepared, ai'e suitable for several grades of paper,

including b®ok, blotting, and writing. It has been found by experience that they must be treated somewhat differently in the beater

than rag stock.

Data and information have been furnished the Siamese Legation

to enable the Siamese Government to purchase in this country neces- sary equipment for an experimental paper mill, to use native materials, such as rice straw, lalang grass, and wild banana.

Details of necessary equipment for a paper-testing laboratory have

been furnished, including the various tj^pes of instruments that are most satisfactory.

In microscopy and photomicroscopy of paper-making fibers stains are necessary for identification and to bring out the characteristic

markings of the fibers. Information in regard to these has been

furnished.

Several samples of paper have been submitted for identification

as to source of manufacture. This is not always possible, but in

some cases the paper is so characteristic of a certain mill that it may

be done. The comparison or contrast of two papers thought to be

the same is easier.

Considerable information and assistance has been given the Tariff

Commission in regard to trade customs, nomenclature, etc.
218 KEPORT OF DIRECTOR OF BUREAU OF STANDARDS.

A large number of inquiries in regard to various paper-testing

naethods and suitable testing instruments have been received. The

publication of the accepted methods (Bureau of Standards Circular

No. 107) will somewhat lessen the burden of these inquiries.

Because of the shortage of raAV material for paper manufacture

during the first half of the fiscal year there was considerable interest shown by the public in the development of various grasses, straws,

and fibers for ^this purpose. In most cases it was not necessary to

consider the mamifacture of paper from these fibers. Paper can be

made of nearly any vegetable fibrous materials, and most of the so- called " new " fibers have been tested during the last hundred years.

In practically all cases the cost of collection, the low yield, the cost

of conversion into paper, and the low grade of paper that might be

obtained would not warrant investing money in a mill for this purpose.

Considerable interest has been expressed in clays for fillers and

for coating, but it has not been possible to give any definite information on the actual value of any clays submitted for this purpose.

Suggestions and information on specifications have been given in

reference to wrapping paper for department store use, loose-leaf

ledgers, and various book, writing, and bond papers. However,

aside from specifications for Government use, no definite specifications have been recommended as yet for general use by the public.

Information has been given on the following grades of paper:

Cigarette, book, bag, blue print, blotting, container board, index

bristol, bond, kraft, manifold, ledger, corrugated board, India, roofing felts, neAvsprint, manila, wall board, drawing, carbon, straw,

bristol board, waxed, envelope, coated book, insulating, Jacquard

cards, etc. Conferences.—Several conferences were held during the j^ear in

reference to the specification for paper to be purchased by the Government Printing Office. Eecommendations were made that a 5

per cent tolerance be permitted on weights, and that thie quantities

specified should be reasonably definite.

Monthly meetings have been attended and tentative specifications

for lime and limestone for use in the manufacture of sulphite pulp

have been submitted.

Assistance was given to the General Supply Committee in regard

to the specifications for paper in Class I. An attempt was made to

make these more uniform and have them conform as much as possible to trade practices and grades.

A revision of the specifications of the Post Office Department for

the purchase of envelopes for departmental use was recommended.

These sj^ecifications were faiilty in some cases and were not uniform.

It was recommended that manufacturers' names and mill brands be

left out of all proposals, and that the awards be made on bids submitted on specifications.

To increase the value of the work of the paper section to the

paper industry it was requested that the American Paper and Pulp

Association appoint a committee to cooperate with the section. Two

conferences have been held, and the whole question of research work,

standardization, and siDecifications is more clearly understood.

1
EEPORT OF DIRECTOR OF BUREAU OF STANDARDS. 219

Relation to the Paper Industry.

Definite contact with the paper industry is being maintained

through membership on commi'rtees of the Technical Association of

the Pulp and Paper Industry and through the advisory committee

of the American Paper and Pulp Association. Closer cooperation

with and greater service to the paper industry is gradually being

accomplished, and the opportunity of assisting the industrj^ is greater

than ever before. Actual cooperation with the mills on larger problems will follow more and more.

Publications.

The following is an enumeration of the publications issued by

this section

The testing of paper, B. of S. Circ. 107. A study of test methods for the purpose of developing standard specifications

for paper bags for cement and lime, B. of S. Tech. Paper 187. Method for differentiating and estimat ng unbleached sulphite and sulphate

pulps in paper, B. of S. Tech. Paper 189.

Su.tabilit.v of paper and cotton bags in relation to burlap bags for sand. Paper

Trade Jour., May 19, 1921.

LUBRICATING OILS.

Standardization of Instruments.

A general review of the work in standardizing methods of test w^as given in a paper read at the annual meeting of the American

Petroleum Institute, Washington, November, 1920, and published

in Journal of the Society of Automotive Engineers, volume 8,

page 481, 1921.

A paper on the " Flow Through Short Tubes " was published by

the American Society of Civil Engineers, No. 21-C, March, 1921.

The laws of flow, here discussed, form the basis of all work on the

calibration of efflux viscosimeters.

The paper on the MacMichael Viscosimeter, mentioned on page

226 of last year's annual report as prepared in collaboration with

the Bureau of Mines, was published by that Bureau in Reports of

Investigations, Serial No. 2201, January, 1921.

The new Saybolt fuel oil viscosimeter is described in report of

committee D-2, American Society for Testing Materials, 1921, and in

Bulletin No. 5 (p. 24), committee on standardization of petroleum

specifiications.

Plasticity.

The subject of plasticity (as defined in Scientific Paper No. 278)

is of interest in connection with lubricants, since greases are plastic.

Much new information has been obtained in regard to the methods

of measuring plasticity by the following investigations

1. Eeport of an investigation of the consistency of starch and

dextrin pastes will be published shortly in the Journal of Industrial

and Engineering Chemistry.

2. The consistency of varnish, some samples of which are plastic, is

discussed in Circular No. 127, Paint Manufacturers' Association of

the United States (National Varnish Manufacturers' Association

cooperating), June, 1921. This investigation was conducted at the
220 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Bureau of Standards oil laboratory, and a special plastometer designed for this work is illustrated on pages 14 and 25 of the abovementioned circular.

3. The consistency of fats used in cooking was investigated in

cooperation with the Bureau of Home Economics, Department of

Agriculture, but the results have not yet been published.

4. In a paper " On plastic flow through capillary tubes," by E,

Buckingham, presented before the American Society for Testing

Materials, June, 1921, the work of previous experimenters was discussed and a new equation proposed. Another paper in which the

matter is treated in greater detail will appear shortly in the Journal

of Industrial and Engineering Chemistry.

Physical Tests.

During the year routine tests were made on 661 samples for Government departriients and special tests were made on 51 samples for

private parties. Thirteen Saybolt universal viscosimeters were ex- amined to determine whether the dimensions were standard.

Cooperative Work.

In addition to the usual cooperation with the American Society

for Testing Materials and the committee on standardization of

petroleum specifications, assistance was given the committee on prime

movers of the National Electric Light Association in the preparation

of specifications for steam turbine oils, published in their report.

Eesults of an investigation of the " float test " for finding the consistency of asphaltic material was reported to Gommittee D-4 of

the American Society for Testing Materials, at whose request the

work had been undertaken.

8. METALLURGY.

The Metallurgical Division concerns itself with research, investigation, and testing

as related to metals and alloys, except built-up metal structures and the processes of extraction of metals from their ores. Its functions include the production of metals

and alloj^s, 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 development 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

coding 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 m.etallurgical processes, such as production of pure metals,

welding, and determination of gases in metals. GENERAL.

Position of the Metallurgical Division.

The Metallurgical Division concerns itself with experimental

research and the acquirement of knowledge in fields related to products metalhirg}'- as distinguished from process metallurg}^, which

last has to do with the extraction of metals from their ores and

smelting and refining operations. The field covered is very large,
REPORT OF DIRECTOE OF BUREAU OF STANDARDS. 221

•embracing not only manufacturing operations both for iron and steel,

but also for nonferrous metals. An endeavor is also made, particularly in cooperation with specification-making bodies, to keep

abreast of the times in the formulation of metallurgical standards

and specifications for metallurgical materials.

The Metallurgical Division is already committed to the solution

of a number of very important fundamental problems looking to

betterment in metallurgical practice. Most of these problems have

been outlined in collaboration with technical societies or groups

specially formed for the purpose of following up progress in the

various subjects.

Among the most important of these may be mentioned the investigation of the effect of sulphur and phosphorus in steel, which is being carried out in cooperation with the steel manufacturers,

specification-making bodies, including the railroads and shipping

interests and Government departments. This is a fundamental

problem of the greatest economic importance to our steel industries.

The investigation of the underlying causes and characteristics of

corrosion of metals, which will involve elaborate laboratory research

and extended field investigations in various soils with many t^'pes of

material, is being outlined systematically under the auspices of a

joint committee now being formed. In the welding of metals

several industries, such as the street railways and shipj^ards, have

come to realize that there are a great many problems of practical

importance which can be solved only by extended scientific research.

These problems are being outlined by committees representing the

street railwa3'S, shipping, and manufacturinir interests. The subject

of gases in steel is one of the most baffling in all the field of metallurgy, and enough has already been done at the Bureau and elsewhere to emphasize the importance of this problem. There is in formation a committee advisory to the Bureau on iron and steel, and it is

hoped that financial support may be forthcoming for the numerous

important problems which ought to be studied at the Bureau's

metallurgical laboratories. The investigations that the Bureau has

carried out on railroad materials, particularly chilled-iron car

wheels, ingot problems, and the role of temperature in metallurgical

problems, have excited widespread interest and it is highl}^ desirable

to continue effective work along these and similar lines.

OPTICAL METALLURGY.

Metallographic Etching Reagents and Methods.

1. Nonferrous Metals.—This investigation, mentioned in last

year's report, has been continued during the year. The results obtained for copper, which was the first type to be considered, were

published during the year as a Bureau scientific paper. The .second

series, which included the copper alloys—that is, brasses and bronzes,

nickel and its alpha alloys—has been completed, and the results

will soon appear in ])ublished form. The principles underlying the

etching of copper—that is, a slight solvent action and an accompanying oxidation—hold true for copper alloys and to a slightly

less extent for nickel and its alloys. Some new etching methods
222 KEPOKT OF DIEECTOR OF BUREAU OF STAIfDARDS.

were developed for nickel, among which may be mentioned the use of concentrated hydrochloric acid, which in many cases gives results

much superior to those obtained by I'eagents in more common use. The third series includes aluminum and its alloys. The study of

this metal has already been started.

2. Special Steels.—The characteristic properties of many of the

special alloy steels, including chromium ancl high-speed tool steels,

depend upon the microstructural constituents which' make up the

alloy. In many cases the exact nature of some of these constituents

is a matter of controversy. Special reagents for identifying such

constituents under the microscope are necessary, and considerable

progress has been made in this study, particularly in distinguishing

constituents which are the result of nitrogen such as may occur in

arc-fusion steel welds, from those caused by the carbon content, and

in the development of suitable reagents for the carbides in the various special steels. Most of such reagents are of an oxidizing nature

and very sti'ongly alkaline in their reaction.

Deep Etching as a Means for Metallographic Study.

The microscopic features of steel revealed b}' the use of concentrated acid as an etching medium were discussed in last year's report.

This method of etching has the disadvantage that the surface is very much roughened and the specimen can not be used for subsequent examinations without regrinding and polishing. An etching

reagent consisting of an aqueous solution of ammonium persulphate

was developed during the year by means of which most of the

structural features of iron and steel which are ordinarily disclosed

by " deep etching " may be revealed. The etching consists of a

relatively light attack, and the specimen is not spoiled for subsequent examinations, as is the case in deep etching with acid. The

results have been published as a scientific paper.

Structural Changes Accompanying the Tempering of Hardened

Steels.

The structural changes which occur in hardened steels upon re- heating (tempering) can readily be disclosed by special means, particularly by a measurement of the changes in different phj^sical

properties of the steel. The changes as observed by means of the

microscope are relatively slight, and but few significant mici-ographs

bearing upon this point have ever been published. This investigation, which is over one-half finished, is being carried out upon five

different steels varying in carbon content, each of which was hardened at several different temperatures, and each of which subsequently received different degrees of tempering. Thus the effects

of the three variables—carbon content, hardening temperature, and

tempering temperature-—upon the structural conditions and the

hardness are being considered. Over 800 specimens are required for

the complete study, each of which varies somewhat in its heat treatment, and hence in its microstructure.

Intercrystalline Brittleness of Soft Metals as a Result of Corrosion.

The results of the study of embrittled lead have been previously

described in a Bureau scientific paper (No. 377). An investigation

to supplement these results was carried out to show to what extent
REPOET OF DIKECTOR OF BUREAU OF STANDARDS. 223'

the application of stress to the metal while subjected to corrosion

aids in the deterioration of the material, and also the observations

were extended to other soft metals besides lead—that is, aluminum,

tin, and zinc. The results have been prepared for publication and

will soon appear as a Bureau scientific paper. In general, it may

be said that lead appears to be more subject to deterioration of this

type than do the other metals studied. Aluminum, because of the

impurities the commercial metal always carries, sometimes develops

intercrystalline brittleness as a result of corrosion, but tin and zinc

show no pronounced tendency toward it. The simultaneous application of stress to a metal under corrosion, as exemplified in the case of lead, is a powerful adjunct to deterioration by the development of

intercr3^stalline brittleness.

Other cases of intercrj^stalline brittleness in metals were submitted

to the Bureau for examination, and include the following: Duralumin sheet, used as " all-metal " airplane covering, and platinum

crucibles containing a slight amount of tin.

Corrosion of. Chromium Steels.

A stiidy of a composition different from the " stainless steel " in

common commercial use was undertaken. Nine alloys differing in

carbon and chromium content were prepared by means of the electric induction furnace. These were pressed into plates, machined

into cubical specimens, so that the surface area could be measured,

and then subjected to corrosion in acid. The loss of weight per unit area per day will be used as a measure of the relative corrodibility

of the different alloys. The corrosion tests are still in progress.

Distribution of Phosphorus in Low Carbon Steels.

This investigation, which was mentioned in last year's report, has

been completed and the results summarized and submitted for publication as a technologic paper. The irregularity of microstructure

as found in the steels after various heat treatments, and the presence

of an unusual cellular-like structure within the individual grains

as developed by etching, are attributed to the nonuniform distribution of the phosphorus, which varied in content within the limits

0.008 to 0.115 per cent. In general, the results confirm those obtained in the previous study of wrought iron of high phosphorus

content.

Effect of Abrasion Upon the Hardness of Steel.

The hardening effect of abrasion upon steel is well known. In

order to determine to what extent Brinell and scleroscope hardness,

as well as microstructure of steels, are affected by rough treatment

during the grinding processes a series of examinations was carried

out. The results indicated that the hardening effect was confined

almost entirely to a very thin surface layer, and that the Brinell and

scleroscope hardness were not affected to an appreciable extent

after rather rough treatment, such as excessive cuts by a surface

grinder. Much of the hardening of steel by abrasion ordinarily

observed appears to be the result of the heating by friction and the

subsequent " quenching action " caused by the relatively cool metal

of the interior of the piece.
224 REPORT OF DIRECTOR OF BUREAU OF STAITDARDS.

Microphotographical Work.

The microscopj^ of metals involves considerable photographical

work, since all permanent records are made in this way. During the

year 3,047 micrographs have been made, 256 of which related to materials submitted for test, the remainder more in connection with the

various investigations in progress.

Use of Etched Balls in the Brinnel Hardness Test.

At the request of the chairman of the committee on new hardness

testing machines of the Engineering Division, National Research

Council, a study based upon a suggestion which had previously been

made to the committee concerning the use of etched balls in the

Brinell hardness test was made. The ball ordinarily used for the

Brinell test is made of chromium steel. The composition is such

that even in tlie hardened state many microscopic particles of car- bide exist throughout the material. These carbide particles are miich

harder than the matrix in which they are embedded. Slight etching

of the surface is sufficient for exposing them, and when an indentation is made, as in the ordinary procedure of the Brinell hardness

determination, each carbide particle produces its own indentation, so that the impression of the ball has a " matt finish." Such impressions

are much more^ conspicuous on a polished surface of a hard steel

than are similar ones made by an unetched ball. The method appears to be very useful for extremely hard steels, particularly if the

surface has been polished. For softer materials there appears to be

but slight advantage, if any, to be gained by etching the ball previous to use. Proposed New Investigations.

In addition to the continuation of the various investigations now

in progress as outlined above, the following proposed lines of new

work for the coming year may be mentioned. In connection with

the study of corrosion a further examination of zinc-coated products

has been planned in cooperation with committee A-5 on the corro- sion of iron and steel of the American Society for Testing Materials,

with the ultimate aim of drawing up specifications for materials of

this kind. Steel and iron differ in a pronounced manner among

themselves in their resistance to atmospheric corrosion, according

to the copper content of the metal. The difference in the protective

oxide coating appears to be responsible, at least in part, for the

difference observed in the rate of corrosion. An examination of the

oxide coatings produced by atmospheric corrosion on various types

of steels has been proposed.

In connection with a study of different types of welded rail joints,

in which the Bureau has been requested to cooperate, considerable

work on the structure of welded products will be necessary. This

will include the various types of welding in industrial use, electric, hot-flame, and thermite welding.

THERMAL METALLURGY.

New Equipment.

An automatic temperature control for electric furnaces was obtained during the 3'ear, and in addition a number of furnaces, pyrometers, and auxiliary equipment formerly used in the heat treat-
REPORT OF MRECTOR OF BUREAU OE STANDARDS. 225

ment of gauo-es were combined with the equipment of the heattreatment section. Rearrangement of this equipment to provide adequate facilities for the hardening of high-speed tool steels, using y

single or double preheating methods, is now in progress. Experimental units for treatment of small samples in vacuum or definite

atmospheres, such as hydrogen, nitrogen, etc., were* also constructed.

Effect of Heat Treatment on Properties of Structural Steels.

Investigation of the effects of heat treatment on the properties

of structural steels, with particular attention to the newer types of

alloy steels for which special advantages have been claimed, has

been continued. 'Some progress in testing the carbon-chromium and

3| per cent nickel steels mentioned in last year's report and a carbonuranium and high (air-hardening) nickel-chromium steel has been

made, while in the following cases the studies undertaken have led

to definite conclusions or have been completed

One Per Cevt Carton Steel.—The tests originally planned for this

steel have been completed. The effects of varying time-temperature

relations in heat treatment on tensile and impact properties, hardness, and structure of 1 per cent carbon steel have been studied,

including {a) effect of temperature variation in hardening, (5) time

at hardening temperatures both above Acm and between Acl and

Acm transformations, (c) effects of tempering steel hardened in

different ways and effects of " soaking " just under the lower critical

range, and {d) comparison of oil and water hardening for production of definite strengths.

Molyhdenuvi. Steels.—Tests were made of heat-treated carbonmolj'-bdenum steel containing about 0.25 per cent carbon and 1 per

cent molybdenum in an effort to correlate the m.echanical properties

with the " lowering " of the transformations. When quenched from

relatively high temperatures within this "lowering range," better

combinations of tensile strength and ductilit}/ and higher impact

resistance were obtained than when hardened from lower temperatures. Similar experiments carried out on a widely recommended

chromium-molybdenum steel containing about 0.30 per cent carbon,

0.90 per cent chromium, and 0.50 per cent molybdenum, show that

the lowering of the transformations does not occur on slow cooling

until tem.peratures much higher than those ordinarily used in hardening structural steels are reached. Following completion of these

tests in the near future a publication will be prepared and, if possible, will be followed by experiments with other types of structural

molybdenum steels.

Artificial Seasoning of Hardened Steels.

While it has not been possible to continue work on this investigation, reported under "Gauge steels" in 1920, available data have

been summarized and a report prepared. The results of this work

will shortly appear in technical journals.

Tensile Properties of Steels at High Temperatures.

Boiler Plate.—Based on a large number of tests made with a specially constructed apparatus as reported in 1920, a report was

prepared entitled "Effect of Temperature, Defonnation, and Eate

649S4—21 15
226 EEPOKT OF niEEUTOR OF BUREAU OF STANDARDS.

of Loiuling- on the Tensile Properties of Low-Carbon Steel below the

Thermal Critical Range." A summary of the work involved m its

preparation is given in the following

1. An apparatus was devised for studjdng the changes in tensile

properties of metals at various temperatures, including determination of the limit of proportionality. A modified form of this equipment was also devised for studjdng the effects of variation in rapid

rates of stress application on these properties.

2. Changes in tensile strength and ductility of several grades of

boiler plate from 20 to 460° C. were determined. In addition, the

effect of the following variables on the high-temperature properties

of low-carbon steel was investigated: Cold rolling (tests on longitudinal and transverse samples), blue roiling (tests on longitudinal

and transverse samples), tensional elastic overstrain, rate of loading

(sloAv and rapid loading).

3. Partial annealing of cold and blue finished steel was also

studied, and the final report includes selected bibliography on the

mechanical properties of ferrous allo3'S at elevated temperatures.

Alloy Steels.—Comparison tensile tests of several structural alloy

steels of acknowledged industrial importance and carbon steel of

similar carbon contents at temperatures up to 550° C. were completed. The following were the type steels tested

steel type.

1 —^

Composition (per cent).

c. Xi. Cr. V.

A :.. .. 0. 38 .38

.38 .38

B 3. .5 C 3.0 1.0

r> 1.0 0.20

While the request for this work originated in the Ordnance Department, because of trouble encountered in converters used in nitrogen fixation by the Haber process, the data obtained are of value

in a Avider field, including high-pressure steam installations, crudeoil distillation, etc. The chromium-vanadium steel was found to be

tlie strongest of the alloys tested at 550° C, showing more than twice

tlie stvengtii and limit of proportionality of carbon and 3i per cent

nickel steels.

Tlicrmal Analysis,

Autographic Method for Ohtaliu'iig Incerse Heating and Cooling

Curves.—The method of determining tliermal transfoi-mations in

metals, such as carbon and ailo}' steels, which has been the standard

method in use at the Bureau for the past few j^ears, requires more

time for plotting the desired curves than to obtain the actual test data. An autograpliic attachment for present equipment was designed in order to make the routine determinations of thermal transformations more efficient and is now under construction. If suc- cessful in operation, it will be possible to make use of this equipment in metallurgical research as well, halving the time required

for tests.
KEPOET OF DIRECTOR OF BUREAU OF STANDARDS, 227

MagneMc Method of Deiermhilng Critical Ranges in Ferrous

Alloys.-—Magnetic methods of determining critical ranges have

been widely used by Japanese investigators duri)}g tiie past few

years in studying tlie constitution of alloy steels, and it has been

intimated that such methods are better ajlapted to metallurgical

investigations of this sort than the thermal methods more generally

used. A simple apparatus was constructed for correlation of transformations determined by thermal and magnetic methods, preliminary to construction of more refined equipment for use in research

work.

Iron-C'arljon Alloys.—Publication of results obtained in determination of transformations of pure iron-carbon alloys fundamental

in the heat treatment of steels has been delayed on account of the

resignation of the staff member charged with the greater part of

this work. This report will, hoAvever, be completed, it is expected,

during the coming year.

Transformations in Alloy Steels.—Critical ranges of various alloy

steels have also been determined from time to time as samples have

been received. This work, which of necessity progresses slowh^, will

in time result in accumulation of valuable data.

ElTect of Surrounding Atmosphere on Heat Treatment.

Annealing and hardening of low, medium, and high cai'bon steels

in definite atmospheres was carried out. Preliminary tensile tests of steels so treated in hydrogen, nitrogen, and vacuum showed no

changes in properties which could not be explained by differences in

cooling rates or surface decarburization. However, hydrogen an- nealing of several brittle sheets supplied by one of the research

associates resulted in a marked decrease in brittleness which Avas

not again observed upon cold rolling. Upon completion of the

preliminary tests now in progress further tests will be undertaken,

providing such work appears Avarranted.

Heat Treatment of Carbon Steel.

This iuA-estigation Avas outlined in last year's report as an investigation being conducted in cooperation with the National Research

Council in order to increase our present knowledge of the production

of sorbite, both by determining the cbnditions of sorbitizing and

determining the influence of the important variations of tensile and

impact properties of the resulting sorbite. During the year progress has been made, although, because of the extended illness of the

member of the staff working on this problem, no definite results can be given at this time.

Proposed New Investigations,

In addition to continuing Avork on the different inA^estigations

now in progress, as noted in several instances above, the folloAving

studies are planned f®r the coming year: («) Continuation of tensile tests of alloy steels at high temperatures; ih) effect of var^dng

heat treatments on the cutting efficiency (for A-arious operations) of

some tool steels in cooperation Avith the Structural Materials Division; (c) effect of several alloying elements on the properties of

cast iron ; {tl) temperature variations in large masses during quench-
228 r.iPOHT OF DIKECTOK OF BI'KEAU OF h'TAXDAEDS.

ing in commercial media and effect of size in heat treatment of given

steels; (e) studies of the heat treatment of special structural alloy

and high-speed steehs.

MECHANICAL METALLURGY.

Effect of Rolling Conditions on the Properties of a Medium Carbon

Steel.

This investigation, mentioned in last year's report, to determine

the effects of certain rolling variables upon the properties of the

finished product, has been nearly completed. The material used

was an electric steel of 0.45 to 0.50 per cent carbon, of good homogeneity and soundness, thus eliminating as far as possible the consideration of the material as a variable.

The effect of the variables was determined by means of mechanical

tests of rolled plates. Longitudinal and transverse tensile and impact tests were made on each plate rolled. At least two plates were

rolled under each set of rolling conditions.

The results obtained indicate that the pass reduction has the

greatest effect on the strength of the rolled material. The other

factors are in this order, finishing temperature, initial temperature,

and roll speed. None of these variables, however, have any marked

effect upon the usual mechanical properties. At present certain of

the results are being confirmed by additional tests and a few additional conditions are being studied. The results when completed will

be published as a technologic paper.

Following this investigation it is hoped to make similar tests on

other representative steels and nonferrous material and to compare

the effects of rolling or forging of the same material.

Fish Scaling of Enamels.

In cooperation with the Ceramic Division some work has been

done on the preparation of iron and steel sheets for enameling.

Previous studies by the Ceramic Division indicated that stock which

had been cold-Avorked was not as susceptible to " fish scaling " of the

enamel coat as was similar material not so worked. Samples were

prepared cold-worked in various manners, and after enameling substantiated the earlier results. It was also observed that a previous

roughening of the stock, as with a fine corrugated roll, followed by

cold rolling, further decreased the tendency to fish scale. The laboratory tests are being followed by similar tests on a larger scale in the

steel mills and enameling plants.

Bearing Metals.

A technologic paper (No. 188) has been issued giving the results

of tests at elevated temperature of five typical white-metal bearing

alloys, four of which correspond to alloys specified by the Society of

Automotive Engineers. The results of compression tests and Brinell

hardness tests at temperatures up to 100° C. show that tin-base alloys

maintain their properties better at elevated temperatures than the

lead-containing alloys. It is also indicated that the addition of lead

in amounts up to 5 per cent in a high-grade Babbitt does not affect

the yield point or ultimate strength at 25 or 75° C. The yield point
REPORT OF DIRBOTOR OF BUREAU OF STANDARDS, 229

of tin-base alloys is not affected by heating for six weeks at about

300° C, but the yield point is lowered in a lead-base alloy by heating

for two weeks at about 100° C.

At the request of the nonferrous metals committee of the American

Society for Testing Materials there is at present in progress a large

number of tests intended to check and revise a table of properties

accompanying the society's specifications for white-metal bearing

alloys. These tests are being made upon the purest obtainable alloys,

upon commercially pure alloys, and upon alloys made from secondary

metals.

In addition to the work outlined above there is also planned for

the coming year an investigation on the effect of rate of cooling

during solidification on the ]3roperties of bearing metals and also

further work on the standardization of wear and service tests.

Equilibria of Tin-Rich Ternary Alloys.

Some further work has been done on the study of the equilibria

of the tin-rich ternary alloys of copper, lead, zinc, and antimony in

all possible ternary combinations, up to a total of 1 per cent of each

of the added elements. The primary purpose of this investigation is to obtain data which will aid in the interpretation of results obtained

in routine testing of fusible boiler plugs, but it is also of considerable scientific interest. Freezing point determinations show that the

effects of the added elements are neither individual nor additive.

The results are now being assembled for publication, together with

similar results obtained on the tin-rich binary alloys.

Strength of Solders and Soldered Joints.

An investigation has been started to determine the tensile strength

of various grades of tin-lead, soft solders, and the effect of the common impurities upon the properties of such solders. Joints ma<le

with these solders upon many different metals and with various

fluxes will also be studied in an endeavor to arrive at the best procedure for soldering given metal. The testing of soldered joints

requires a means of readily making reproducible standard joints, and

this phase of the problem is receiving first attention.

Fusible Metals for Helium Relief Valves.

In cooperation with the Engineering Physics Division a large

number of fusible alloys have been prepared for investigation as to

their suitability for the pressure-relief valves of helium containers.

The melting range required of the alloy, together with the necessity

of a sharp melting point while under pressure, are rather unfortunate

from a metallurgical standpoint, and considerable difficulty has been

encountered in preparing an alloy which would exactly meet the

requirements.

Thermal Stresses in Chilled-Iron Car Wheels.

Although the experimental work on this investigation lias l^een

completed for some time, as noted last year, the publication of the

results has been witliheld pending an analysis of the data hy the

manufacturers of chilled-iron Avheels. The results indicate that the

maxinmm stresses developed are very close to the tensile strength
230 EEPOKT OF DIRECTOE OF BUKEAU OF STANDARDS.

of the cast iron, and that this maximum stress occurs in the proximity

of the junction of the double plates, at which place failure generally

occurs in the tests conducted at the Bureau. It is expected that the

data obtained will greatly assist the manufacturers and railroad

engineers in imjjroving the design of car wheels, particularly the

larger wheels intended for severe service.

Graphitization of White and Gray Cast Iron.

This investigation is being undertaken at the request of manufactiirers of chilled-iron car Avheels to assist them in regulating

their annealing-pit practice. Previous work had shown that the

highest temperature at which no graphitization of the tread takes

place under normal lengths of time is about 720° C. Continuing

this work, samples of white and gray cast iron have been annealed

tit low temperatures (less than 70()° C.) for various lengths of time

up to 12 days. The experimental work is now completed and the

results will shortly be published.

Thermal Stresses in Steel Car Wheels.

An investigation of the thermal stresses in steel car wheels re- sulting from brake action on long grades, similar to that carried out

on chilled-iron wheels is in progress. A large number of rolled,

forged, and cast-steel wheels, both new ones and those which have

been in service, have been secured for test. So far none of the steel

wheels have failed under conditions identical with those Avhich gave

rise to cracked plates in chilled-iron wheels.

Owing to tlifference in design of the steel wheels as compared

with th chilled-iron wheels, the distribution of the thermal stresses

is somewhat different in the two types. In the chilled-iron wheels

it vv^as found that the front of the wheel was all in tension. The tests on the steel wlieeis show that the front of the wheel is in compression near the tread and in tension near the hub. The stresses

on the back of the steel wheels, which are negligible in the chillediron wheels, are now being studied. The steel wheels will also be

subjected to higher tread temperatures in an endeavor to determine

their ultimate capacity tn resist thermal stresses as compared to the

chilled-iron wheels.

Corrosion of Iron-Silicon Alloys.

The tests of acid-resisting alloys of the iron-silicon type, mentioned

in the report of last year, have been continued. The work was con- siderably delayed owing to difficulty in securing a continuous steam

supply during the mild winter just past. This difficulty has now

been overcome by the use of individual steam baths for the hot tests,

but since only a limited number of tests can be in progress at one

time the entire i^rocedure consumes considerable time. However, it

is anticipated that during the coming year these tests, together with

others on nonferrous acid-resisting alloys, may be reported.

Titanium Treated v. Untreated Rails.

This investigation is being carried out in cooperation with the

Titanium xillo3's Co. and the Illinois Central Eailroad Co. and is a continuation of previous work done by the Bureau in studying

various processes of manufacture of steel rails, with a view to de-
EEPORT OF DIRECTOR OF BUREAU OF STANDARDS, 231

termining the proper methods of manufacture to insure sound rails.

Samples from several heats of steel, with and without titanium,

have been taken from the rails and are being surveyed for chemical

homogeneity and soundness, uniformity of mechanical properties,

microstructure, etc. The rails have been laid in portions of the track

of the Illinois Central Railroad, where their performance will be

closely watched.

Pure Platinum Wire.

Rolling and drawing equipment has been obtained for producing

fine wire from the extremely pure platinum and platinum metals

refined by the Chemistry Division. It has been found possible to

draw these metals to quite small diameters without contaminating

the original pure material. The equipment will be used for preparing standard thermocouple elements and material for studying

the properties of platinum and platinum alloys.

Metal Specifications.

The Bureau is continually cooperating with Goveriunent departments and outside agencies in the formulation of specifications for

metal products. Among those receiving such aid during the past

year mention may be made of the Navy Department, War Departs

ment, Panama Canal, Library of Congress, Society of Automotive

Engineers, American Society for Testing Materials, and the National Advisory Committee for Aeronautics. Many requests are re- ceived from outside parties for specifications for metallic products.

Generally, existing specifications can be submitted, but in some

cases new specifications are written to cover the request.

New Apparatus.

An instrument has been developed to measure the percentage

elongation of broken tensile specimens, so as to eliminate the errors which are possible in the usual methods of measuring this factor.

It consists essentially of a clamp to hold the specimen and two

movable indices. When these indices are placed in the gauge marks,

their relative position actuates a pointer over a dial which gives

directly the percentage elongation. A paper describing the instrument is in press, in which data are given showing the results obtained in measuring elongation by various methods.

Continuation Work and New Work.

Mention has been made in the various items of the work which it

is planned to continue during the coming year in this section. This

includes the determination of the properties of metals as affected

by various conditions of rolling, forging, or drawing; investigation of the properties of different grades of bearing metals, both

at room and at elevated temperatures, in combination with the effect

of pouring and casting conditions; a study of the strength of

soldered joints and the proper combinations of solder and fluxes to

be used for various metals; the corrosion of acid-resisting alloys;

measurement of the thermal stresses in steel car wheels ; a survey of

rails made from steel treated with titanium and similar steel untreated.
232 KEPOKT OF DIKECTOK OF Bl'REAL" OF STAXDAKDS.

A large number of new investigations are also planned, some of

Avliich are briefly described, as follows: It is planned to make determinations of the specific heat of metals up to and possibly above

their melting points, and also of the latent heat of fusion. These

data are of great value in metallurgical calculations, and for many

of the metals the data at present available are not reliable.

It is expected that a study will be made of the hardness of the

crystals of pure metals and of the microscopic constituents of alloys. It is hoped that this information will be of value in interpreting the pi'operties of metals and alloys and of academic interest in considering the various theories regarding the structure of

metals.

After careful standardization of the methods of making wear tests efforts will be made to conduct Avear or service tests upon bearing

metals. There is a continued call for such tests from the industry,

but because of the large number of variables involved it is at present

impossible to make tests of this kind which are satisfactory and truly

comparable.

The Bureau's attention has recently been called to a large number

of failures of car wheels occuring on one of the street car lines run- ning into the District of Columbia. It is hoped to gather statistics

on similar failures for all the car lines of the District and to determine the conditions which are responsible for the trouble encountered.

CHEMICAL METALLURGY.

Gases in Metals.

Method for Total Gas m Metals.—The method referred to in last

year's report for determining the gases evolved from metals heated

or fused in vacuum has been further developed and applied to steels

and some nonferrous metals, particularly nickel, monel, and copper.

It has been possible to eliminate the use of fragile and complicated

mercury sample-collecting vacuum piunps. substituting therefor a simple mechanical vacuum pump. The metal sample to be tested is

heated within an evacuated silica or glass tube, and the gases evolved

are immediately drawn through a train of absorbents by the mechanical vacuum pump. Water and carbon dioxide are absorbed in tubes

immediately following the vacuum furnace. The remaining gases

are drawn through a furnace containing cupric oxide heated to 20C

to 300° C. whei'eby hydrogen and carbon monoxide are oxidized to

water and carbon dioxide and absorbed in the following tubes. Provision can also be made for burning and absorbing hydrocarbons

when they are present by the use of a second copper oxide tube heated

to a higher temperature. Nitrogen may be determined by absorption

in metallic calcium vapor, as outlined in the direct method for nitrogen described below.

Tests with |.aiown gases and mixtures have shown the absorption

or oxidation of water, carbon dioxide, hydrogen, carbon monoxide,

and nitrogen to be fairly complete under the low pressures Avhich

exist in the absorbent train in this method. The high-frequenc}^

induction furnace is the most satisfactory means of heating the metal

samples in this method, although for applications of the method in cases where only temperatures below 1,000° C. are required nichrome

or chromel resistance furnaces are satisfactory.
REPORT OF DIRECTOR OF BUREAU OF STA STtARDS. 233

A preliminary publication on this method is in preparation, describing the absorption train used and the application of the AjaxNorthrup induction furnace to the heating of the metal sample.

Direct Method for Nitrogen.—¥vx^%x improvement and tests have

been made on the direct method for the determination of nitrogen

by absorption in metallic calcium vapor. Briefly, the method is as follows: A small piece of calcium is heated to 700° to 800° C. within

a silica tube evacuated to a pressure of a few millimeters of mercury, an inner tube of iron keeping the calcium vapors from coming

in contact with the silica. When the vaporization of the calcium

begins, as indicated by a decrease in the pressure within the tube,

the nitrogen or gas-containing nitrogen to be analyzed is admitted at a rate which does not allow the pressure within the tube to increase

to any great extent. About 50 cubic centimeters of gas will be absorbed in three to five minutes. When the absorption is complete the

furnace is cooled, the iron inner tube containing the calcium nitride

and other oxidation products of the calcium is removed, and the contents of the tube dissolved in ammonia-free hydrochloric acid. The

nitrogen in the calcium nitride is thus converted to ammonium chloride and is then readily determined by distillation from an alkaline

solution, absorption in standard acid, and titration.

Analyses made on pure nitrogen have given a recovery of 99,5

to 99.9 per cent of the amount taken. The gas may be either dry

or saturated with moisture. Mixtures of nitrogen with oxygen

have given 99 to 99.8 per cent recovery ; nitrogen with hydrogen,

99 to 99.9 per cent. With mixtures of nitrogen and carbon dioxide

containing not over 10 per cent carbon dioxide the recovery of nitrogen has been 99.6 to 99.8 per cent, but with greater percentages of

carbon dioxide in the mixture results have been low and erratic.

This method will be applied to the determination of nitrogen in

the gas evolved from metals in the work on total gas in metals. The

paper reporting the work is being prepared for publication.

Oxygen and Oxides in Steel.—Some applications of the Ledebur

method for oxygen and microscopic methods for oxides in steel have

been made in the course of the work, described under the heading

" Deoxidizers and slags " below. The Ledebur method is also being

used in conjunction with the work on total gas in metals and is an

aid in the interpretation of the results obtained by the latter method.

Pure Metals and Alloys.

Electrolytic Iron.—During a large part of the past year two or

three electrolytic baths have been running for the preparation of

pure iron. A number of samples of this iron, either as deposited

or after fusion in vacuum, have been supplied to Government laboratories and to educational institutions for use in various research

problems. The larger part of this electrolytic iron has been used in

the preparation of the pure iron alloys mentioned below.

Jron-carhon-mariganese Alloys.—The preparation of this series of

iron-carbon-manganese alloj^s was undertaken with the object of defining more exactly the role of manganese in steel. The carbon content of these nlloys vvas varied in steps of 0.1 per cent from 0.0 to 1.5

per cent; the manganese in steps of 0.2 per cent from 0.5 to 1.2
234 EBPORT OF DIBECTOE OF BIJKEAIT OF STANDARDS.

per cent. The starting materials were pure iron (electrolytic), pure

mano-anese, and an iron-carbon alloy (4.4 per cent carbon), prepared from electrolytic iron and pure carbon. All ingots were

melted in vacuum in crucibles of magnesia very low in silica and

sulphur. Ingots weighing 14 to 2 kilograms thus prepared were

rolled to flat bars. From these bars tensile test specimens were cut,

two from each ingot, and a specimen for magnetic tests. Thermal

analyses, microscopic examinations, and Brinell hardness tests were

carried out on material from the broken tensile specimens.

The tests on the fully annealed samples of all ingots of this series

have been completed. The paper giving the results of this work

will be published early in the coming year. Work on the properties

of alloys of some of these same compositions tested after various

heat treatments is in progress.

Iron-carhon-viangancsc-sulphur Alloys.—A series similar to the

preceding series of iron-carbon-manganese alloys, with the addition

of sulphur in the steps 0.02, 0.04, 0.06, 0.08, and 0.10 per cent, is now

in course ox preparation. These alloys will be treated and tested

in the same way as the iron-carbon-manganese alloj^s, and in addition their behavior on rolling and forging will be noted.

Pure Platinum Alloys.—The preparation of alloj'^s of especially

pure platinum with platinum group and other metals has been undertaken in cooperation with the Chemistry Division. Refractories have

been tested as to their suitability for use in melting pure platiniun

without contamination, and a special high-frequency induction fur- nace coil has been obtained which is adapted to the melting of very

small amounts of platinum by direct induction. Melts of pure

platinum in vacuum ha^'e been made in this furnace.

Gold Alloys.—During the year five series of gold alloys were prepared for use as standards in the quantitative spectroscopic analysis

of gold bullion for the United States mint.

The first three series prepared were gold-silver, gold-copper, and

gold-iron alloys. Under each series there were three steps in the

content of the metal alloyed with the gold, namely, 1. 0.10, and 0.01

per cent of either silver, copper, or iron, as the case might be. At

a later date two more series of alloys were prepared from especially

purified gold furnished by the United States mint. In these series

several impurities were together added to the gold instead of one impurity at a time as in the first three series. Thus, the fourth

series consisted of four melts of gold, containing, respectively, 1, 0.10,

0.01, and 0.001 per cent each of silver, copper, lead, and ii'on. The

fifth series was pre])ared of the same steps in percentage of impurity, but with the omission of the iron.

These alloys were prepared in an induction furnace and, when

necessary, under a stream of hydrogen to prevent oxidation of the

alloying metal. The melts Avere either cast or hammered into rods

2 to 3 millimeters thick and 4 to 6 centimeters long, suitable for use

as spark electrodes.

Refractories.

Magnesia Rcfraetories.—Large quantities of magnesia low in silica

have been prepared from Epsom salts and from basic magnesium

carbonate. This pure' magnesia has been used in the preparation of
REPORT OF DIRECTOR OE BUREAU OF STANDARDS. 285

crucibles and linin_e;s for carbon crucibles, in which many of the

pure metals and alloys prepared in this section have been melted.

Light calcined magnesia and aluminum oxide have been used as binders for the heavily calcined magnesia in the preparation of

crucibles. Eecently it has been found that the addition of from 1

to 8 per cent of magnesia fluoride serves more satisfactorily as the

binding agent.

Special Refractones.—Considerable experience with special refractories has resulted from some of the alloy and electric furnace work

of this section, particularly as related to crucibles and radiation

screens used in the work on gases in metals and crucibles for melting

platinum, gold alloys, titanium, and ferroalloys.

Small experimental crucibles for special work have been made

from pure aluminum oxide, pure lime, mixtures of zirkite-magnesia or zircon-magnesia, zircon-lined graphite crucibles, crucibles of compressed pure tungsten powder, and powdered ferrotungsten. Small

lots of magnesia and of lime have been electrically fused for use in

the preparation of special refractory shapes.

The crucibles of compressed tungsten powder have been found very

useful in connection with the high-frequency induction furnace. Such

crucibles heat very rapidly and efficiently and can be used to heat

to very high temperatures small quantities of materials which heat

with difficulty or not at all by direct induction.

Zircon-lined graphite crucibles have been used with some success in electric furnaces when the atmosphere is oxidizing.

The section has endeavored to keep in touch with the commercial

developments of metallurgical refractories, and especially the less

common refractories for special uses at very high temperatures.

Chemical Metallurgy Standards.

Ladle-Test Ingot Investigation.—In accordance with the program

of the committee of the American Society for Testing Materials

which is handling this investigation, test ingots have been obtained

during the year from nine cooperating steel companies. Two sets of

test ingots were taken by each company from each of several openhearth heats of steels of low, medium, and high carbon contents.

These test ingots were taken by the company's regular px'actice in one case and by the committee's specified practice in the other. The

latter practice modified the company's methods only by the addition

of aluminum to the mold before the ingot is poui-ed. The purpose

of this work is to ascertain (1) whether the aluminum addition

eliminates blowholes in all the types of ingot tested, and (2) wh^her

the aluminum-treated ingots are more homogeneous chemically.

The entire set of ingots has been received at the Bureau, split longitudinally, so as to facilitate the Bureau's examination. The aluminum ingots are invariably sounder and freer from blowholes, regardless of ingot type or pouring practice.

The Bureau is now drilling the ingots at three widely separated

places on the split faces, and the drillings are to be analyzed for car- bon, sulphur, and phosphorus, in order to get comparative results for

chemical uniformity on the aluminum and nonaluminum treated

ingots.
236 EEPOKT OF DIRECTOR OF BUREAU OF STANDARDS.

Invar (36 Per Cent Nickel Steel).

Some work has been undertaken on the preparation and workmg

of invar (36 per cent nickel steel), with the object of determining the

infinence on tlie properties (thermal exi)ansion, aging, etc.) of the

small amounts of impurities present in the commercial alloy.

A number of ingots have been prepared using ingot iron, or electrolytic iron, and shot-nickel, or electrolytic nickel. Ingots have thus

far been made with carbon content fixed, but with different deoxidizers (manganese, silicon, ahuninum) added in varying amounts.

Several of these ingots have been forged and specimens prepared for

chemical and expansion tests. New Equipment.

The transfoimer capacity for the operation of Arsem furnaces has

been doubled by the installation of a new 25-kva transformer and

switchboard giving an^'^ voltage from 1 to 61 in 1-volt steps. This is a duplicate of the previous equipment and makes available for electric-furnace operation 50 kva at any voltage from 1 to 61.

A new 20-kilowatt high-frequency converter for the operation of an Ajax-Northrup induction furnace has been installed. This new

equipment will be used for the preparation of alloys, castings in

chill or sand molds, and for miscellaneous melting and high-temperature work, thus allowing the use of the smaller (10-kilowatt)

converter and furnace exclusively on the problem of gases in metals.

A cabinet sand blast has been purchased and recently installed.

Proposed Work.

Special atteution dviring the coming year will be given to the work

on gases in metals and the application of the method of analysis that

has been developed for total gas in a metal, to steels and nonferrous

metals which have been manufactured by variations in commercial

practice. The lack of definite knowledge of the effects of gases in

metals and of the most efficient methods of control of gas content is

at present the cause of very serious wastes of materials, time, and

labor in almost all metallurgical work.

The work on the properties of alloys of pure (electrolytic) iron

with additions of carefully controlled amounts of impurities will be

continued. The next phase of this work (already undertaken) is the

investigation of the effect of sulphur on such alloys. This work will

correlate with the program of the joint committee on sulphur and

phosphorous in steel which is doing its work in steel mills on a commercial scale.

It is desired to continue more actively the work on special metallurgical refractories, by service tests of some of the newer electric

furnace refractories, and small-scale tests of refractories for very

high temperatures. At present the available personnel permits only

intermittent attention to the work.

The work outlined above under pure platinum alloys should also

be given special attention during the coming year:
F.EPORT OF DIKECTOE OF BUEEAU OF STAiTDAKDS. 237

EXPERIMENTAL FOUNDRY.

Experimental and Practical Castings.

The foundry has continued diiring the past year to serve the

Bureau, research laboratories, and Grovernment departments in the

making of metal and alloy castings. There was an increase over the

previous year from a total of 1,946 castings from 401 patterns to a

total of 2,358 castings from 459 patterns. The total estimated value

of castings made during the year is $2,710.

Molding-Sand Investigation.

During the past year an extensive investigation of 10 different

sands submitted hj the State Geologist of Georgia has been carried

out, the results of which showed that these sands were not natural

molding sands because of their excess of clay. This difficulty, however, was overcome by lessening the amount of water used in the

initial experiments to 10 per cent, making it possible to use any of

them as molding sands. Their uniformly high melting points and

favorable grain size made them all of practical value provided they

were properly tempered for molding purposes.

There is in preparation a circular on foundry tests of moldingsands which it is expected will give descriptions of the more important methods of tests and those in use at the Bureau.

Weathering of Art Bronzes.

As was stated in last year's report, this investigation is being

carried out in cooperation with one of the statuary manufacturers

to determine the relation of the composition of statuary bronzes to

the facilities with which they assume patinas upon exposure to

weather. The specimens have been exposed to the weather since

August, 1916, and it is planned to continue their exposure until 1926.

The various specimens now show to a slight extent the color of the

patina which they may be expected to assume. Government Bronze and Its Substitutes.

Owing to limited personnel the investigation of the influence of

small amounts of Al, Sb, and Ni added to alloys of 88 Cu, 10 Sn, 2

Zn, and 88 Cu, 8 Sn, 4 Zn has not progressed as far as was expected

during the last year. It is proposed to include the effect of the addition of small amounts of iron (from 0.10 to 1 per cent iron). In

one set of experiments the iron is to be added by means of zinc dross,

which contains a limited amount of iron, and in the second set it is

to be added in the form of ferrous oxide. This series of tests is to be

accompanied by photomicrographic studies of the broken test bars.

In addition it is expected that a series of tests will be conducted

in which nickel is to be added in the form of a nickel-tin hardener

which has already been prepared. This method it is hoped will

result in an improvement of the physical properties of the alloys.

ITEMS OF MILITARY INTEREST.

Erosion of Machine-Gun Barrels.

About 20 steels for tliis investigation, recommended b_y the Bureau

to the Ordnance Department, have been prepared. These steels were

selected because of their forgeability, machineability and possible
238 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

resistance to erosion. During the year such data as were desirable

in connection witli the physical properties of these steels have been

collected, the manufacture of the barrels and the firing tests being

conducted at Sprino-field Armory. The results of the tests to date

have demonstrated that several steels may prove to be superior to

the type of steel nov^^ being used in general production. Of the total

of 20 steels prepared, 3 have indicated their superiority to the ordinary machine-gun steel, 6 their ability to equal the ordinary machinegun steel, and 2 have been entirely elimiiiated as unfit, and the re- mainder are probably inferior to the ordinary machine-gun steel.

At present confirmatory firing tests in duplicate are being made on

the steels not yet eliminated and should be completed during the next

year.

Efforts to electroplate gun barrels have not been successful, a re- port of which work is now in progress. Eeports have already been

submitted on the etfect of poor cooling upon the life of gun barrels^

on the causes leading to bore enlargements, and on the relation between the tensile properties of the steel and the accuracy life of the

gun barrel.

Corrosion of Metals by Ammonia Gases.

The War Department, through the fixed nitrogen research laboratory, is interested in obtaining metals capable of resisting corrosion

by gases at high temperatures and pressures. Interest is manifest in

the mechanism of deterioration, rate of deterioration, loss in tensile

properties, permeability to gases, and endurance of metals suitable

for service in the fixation process. A total of 30 alloys is being investigated, 25 of which are steels and 6 nonferrous alloys. The work

so far has progressed to the point where the record of ph3'^sical properties, such as structure, strength, and thermal behavior, has been

completed.

Development of Light Armor Plate.

A research has just been begun on the development of light armorplate. This work requires the rolling, casehardening, and heat-treating of a number of special steels. Firing tests of the finished plate

are to be made at one of the Army ordnance proving grounds. This

research is a part of a larger program undertaken by the Ordnance

Department. The Bureau expects to determine the efficiency of different commercial carburizers in addition to determining the susceptibility of the different steels to carburization.

Tensile Fractures of Gun Steels.

A metallographic investigation of the relation betAveen certain

types of fractui-es and the structure of common steels has been com

pleted, and the work it is expected will be compiled into a summary

of the findings and a classification of the various fractures into groups

or basic types.

Armor-Piercing Bullet Cores.

A study of a number of different types of armor-piercing bullet cores was completed some months ago. The problem involved the

study of several steels differing in composition. A number of heat
REPOEI OF DIIIEGTOR UF BUREAU OF STANDARDS. 239

treatments were applied to each steel and tests were made of those

physical properties which are most desirable in armor-^^iercing bullet cores. The research succeeded in determining the relative fitness

of the different steels for armor-piercing ammunition. The net

results eliminated approximately six of a total of nine types of cores and concentrated design development upon those types remaining.

Miscellaneous Tests for Ordnance.

Among the several special examinations made for the Ordnance

Department on materials which had failed in service or had been

submitted as articles of merit may be mentioned anticorrosion alloys,

platings, alloy steels, bullet cores, tractor parts, tank armor, light

armor, gun metal and nonferrous alloys.

Manufacture and Properties of Steel Plates for Light Armor.

This investigation originated from the need of the Ordnance DepartAient of the Army and the Bureau of Ordnance of the Navy

for information regarding the effect on the ballistic properties of

light armor plate of certain chemical elements, such as zirconiiun.

It was carried out in cooperation with the Bureau of Mines and

the Navy Department.

Although the results on the ballistic properties are not available

for publication, an account of the mechanical properties and tests of this series of somewhat unusual steels was considered of interest,

and a publication dealing with these data is now in press.

About 193 heats of steel, prepared by the Bureau of Mines, containing in various combinations the folloAving elements, carbon, sili- con, cobalt, boron, copper, cerium, molybdenum, chromium, uranium,

and tungsten, have been studied. None of these steels presented

any difficulties in rolling into plates, except those containing boron.

Boron forms a complex eutectic, pi-obably that of an iron-carbonboron compound with iron. This eutectic is fusible at the temperatures ordinarily used in rolling, but at lower temperatures steel con- taining boron can be roiled successfully.

The usual mechanical properties and impact tests were carried out

on all the steels. It was shown that steel containing 4 to 5 per

cent carbon, 1 to 1.5 per cent silicon, 3 to 3.25 per cent nickel, and

O.G to 0.8 per cent manganese and deoxidized Avith a simple deoxidizer

such as aluminum can be produced, having a tensile strength of

approximately 300,000 pounds per square inch, with excellent ductility and toughness. This type of steel is recommended as a structural material for special purposes.

German Motor-Truck Parts.

As part of a stud}^ of the materials used in captured German motor

trucks requested b}^ the Motor Transport Corps, a large number of

ball bearings were examined. The composition and the hardness of

the balls and races are practically identical with similar material

made in this country, a carbon chromium steel being used.

Precision Altimeter.

Following the precision altimeter which was constructed last year

two additional instruments of different design have been constructed

in cooperation with the aeronautical instrument section. The sue-
240 EEPOBT OF DIEECTOE QY BUEEAU OF STAXDABDS.

cess of these instruments is largely due to the attention given to the

material and treatment of the steel springs employed. A paper

describing the necessary precautions to be observed is now in i^ress.

RESEARCH ASSOCIATES.

Tliere have been stationed at the Bureau during the past year six

research associates and assistants in metallurgy, representing industries or organizations which desired to take advantage of the facilities of the Bureau for the prosecution of investigations in which both,

the industry as a whole and the Bureau were interested. This plan

has wori?:ed excellently and could well be taken advantage of by other

industrial organizations. The following paragraphs give an account

of the progress of work of these associates during the year.

Iron in Brass.

The problem of quantitatively determining magnetically gmall

amounts of iron in brass resolved itself into a study of the magnetic

properties of brass containing small percentages of iron. The specimens used Avere cast-brass rods about 13 millimeters in diameter and

12 centimeters long, turned down to size and with a composition of

copper 82 per cent, tin 3 per cent, and zinc 16 per cent. The amount

of iron in the specimens varied from 0.01 to 0.8 per cent. Magnetic

tests indicated that the individual bars were uniform in properties,

while preliminary microscopic examination showed that up to a

certain amoru\t the iron had completely dissolved in the brass in

each case. The method consisted in connecting up two mutual inductances in such a way that their electromotive forces were equal

and balanced each other when no specimen was present. When a sample was introduced in one coil, however, and not in the other,

the galvanometer gave a deflection that was proportional to the sus- ceptibility of the specimen. By this means magnetic susceptibilities as low as 4X10"'' could be measured. From the results obtained in

these first measurements the magnetic properties apparently do not

bear any very definite relation to the per cent of iron in the brass.

The effect of work on the magnetic properties of these specimens, it is expected, will also be studied.

Sherardising.

For this investigation it was found necessary to construct a rotating, wire-wound electric furnace which was so built that the part of

the heat chamber used did not v&rj more than 3° C. in temperature.

Also the effect of the variables, time and temperature, on sherardizing was studied. Samples of iron low in carbon and with few impurities were sherardized at 340°, 370°, 400°, and 430° C. for three hours

and also for one, three, and six houi^s at 370° C. The coated samples,

the gain in weight of which had been noted, were tested by stripping

in antimon}'^ chloride solution, exposing to salt spray, tumbling in a

ball mill, and microscopic examination. The gain in weight during

sherardizing gave the amount of zinc deposited and the loss in weight

by stripping measured the total weight of the coating. The differ- ence between the two gave the amount of iron alloyed with the deposited zinc.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 241

The data collected so far, it is thought, are not extensive enough to

warrant definite conclusions. It is expected to continue the sherardizing inA-estigation by studying the addition to the base metal of

various amounts of silicon, manganese, phosphorus, combined carbon,

and graphitic carbon, and its effect on the sherardized coatings produced, also the influence of the metallic content of the zinc dust and

the rate of rotation during sherardizing.

Researches on Monel Metal.

Alternating stress tests on monel metal which have been done thus

far indicate that hot-rolled monel metal will stand at least 75,000,000

alternations of stress of 38,000 pounds per square inch. A paper in-

•cluding the results of these tests was presented before the June meeting of the American Society for Testing Materials.

The results of tests on monel metal with a Charpy impact testing

machine have been prepared in the form of a paper, which gives the

average of 10 tests as 160 foot-pounds. Tests to determine the impact

values with an Izod machine were not satisfactory, as the monelmetal specimens did not fracture.

Tests on the melting range of monel metal were found to vary

slightly with the composition. The highest range observed was

1,315° to 1,351° C., while the lowest was 1,284° to 1,319° C.

An investigation is in progress to determine the character and

quantity of gas in monel metal with the object of devising methods

of elimination.

Study of Nickel.

Tests have shown that pure nickel melted in an atmosphere of

hydrogen and solidified in vacuo is malleable and may be worked

into shape for the determination of its physical properties. Specimens are now being prepared for the determination of the properties of exceptionally pure nickel furnished by the research department of the International Nickel Co. The density of pure nickel

•cast in vacuo was found to be 8.889 g/cc. at 25° C.

Experimental work on the equilibria of nickel-nickel oxide is in

progress. Unsuccessful attempts have been made to obtain the

solidus of nickel containing small amounts of nickel oxide. It is

believed that the Bureau now has apparatus and a method which

will be suitable.

Deoxidizers and Slags.

During the year a paper was published in Chemical and Metallurgical Engineering (Nov. 3, 1920) giving the results of the first

phase of this investigation. The purpose of this first investigation

was to make a preliminary survey of probable deoxidizing alloys

containing varying amounts of manganese, silicon, titanium, and

aluminum.

The fundamental assumption of the experimental method used

was that the action of desirable deoxidizers should produce deoxidation slags (oxides of the elements in the deoxidized alloy) fusing

below the melting point of steel, the idea being that such fusible

slags would most readily separate from the molten metal, thus freeing it from foreign inclusions. Accordingly, 120 mixtures of oxides

64984—21 16
242 REPORT OF niRKC'TOR OF BX^REATT OF STANDARDS.

of manganese, silicon, titanium, and ahmiinum were made up and

the melting points of these mixtures determined. All oxide mixtures

melting above 1,500° C. were excluded from further consideration.

From the oxide mixtures melting below 1,500° C. the percentage

composition of the alloys corresponding to the oxides was calculated.

As a result of this work 73 possible deoxidizing allo_ys were computed from the determinations of oxide melting points. Nearly all

of thes^ would give deoxidation slags melting well below the melting

point of steel. The other 47 combinations were excluded from further investigation. It Avas shoAvn by this work that titanium oxide

was very effective, not only lowering melting points of such mixtures, but also in conferring greater fluidity on the deoxidation

slags.

The next phase of the work was to make some of the deoxidizing

alloys, devised as a result of the work above described. In planning

this work it was decided to confine attention at first, as far as

possible, to low-carbon alloys, since it is known that the presence of

carbon in some deoxidizing alloys introduces complications by the

formation of carbides with the active elements of the deoxidizer

and by the deoxidizing action of carbon itself. No attempt was made

to produce all the 73 alloys mentioned above, as they were represented by several groups, and there usually was little difference in

the slag-melting jjoints of such group members.

The majority of these alloys made up have been tested to some

extent for deoxidation of steel or commercially pure iron, but the

results obtained are considered far too incomplete to justify any

conclusions at this time as to their relative efficiency for deoxidation.

Such conclusions must await completion of a considerable amoimt of

experimental work, a program of which it is now possible to outline

from the previous work, as follows: (1) Removal of iron oxide,

(2) I'emoval of blowholes (gases), (3) production of sound ingots,

homogeneous chemically and physicall.y, and with minimum amount

of "pipe," and (4) prodiiction of metal that will not break up on

forging; i. e., metal free from solid inclusions and from sidphur

red-shortness. Work along the above lines is in progress, and the

folloAving may be stated tentatively as the result of experimental

deoxidations tluis far conducted

The fundamental assumption underlying the first phase of the

deoxidizer investigation, namety, that deoxidizers giving deoxidation slags fusing above the melting point of iron are undesirable,

has been confirmed. Deoxidations wei'e made with 95 per cent sili- con, 98 per cent aluminum, and with 75 per cent manganese. In

all these cases the deoxidized iron broke u]) on forging and showed

a large amount of inclusions.

It has been shown that some of the combinations of manganese

with silicon and titanium are very effective in cleansing the iron from

solid inclusions—at least so far as the small-scale tests indicate.

It has been found possible on the small scale with some of th&

latter deoxidizers to reduce the Ledebur oxygen content of the

"standard" oxygenized iron from the original 0.06 per cent to an

amount not determinable by the method.

There are indications that magnesium, calcium, and lead when

properly alloyed can be of use for deoxidation of ferrous materials-
REPOET OF Dir;KC:T()R OF BUREAU OF STAiJvDARDS, 243

Effect of Different Elements on Red-Shortness of Iron.

Considerable work has been done in studying the effect of different elements on, the red-shortness (brittleness when worked hot)

of commercially joure iron and electrolytic iron. The following

phases of the work have lieen studied in some detail, and tlie results are to appear later as a technical publication : (a) Effect of small

amounts of sulphur on the red-shortness of electrolytic iron and of

ingot iron; (b) quantitative study of effect of manganese in eliminating the sulphur red-shortness; (c) effect of oxygen on red-shortness

of electrolytic iron where less than 0.01 ]3er cent sulphur is present

(d) effect of copper on red-shortness of iron containing minimum

amounts of sulphur and oxygen and practically manganese free

(electrolytic iron).

GENERAL ACTIVITIES.

Tests.

Tests Involving the Microscopy of MetaJs.—The tests and examinations involving the microscopy of metals are nearly always of an

investigational character rather than I'outine. Considerable research

work is often required ; an interpretation of the results of the microscopic observations and the application of them to the particular case under observation are always necessary. Often recommendations,

particular^ in the case of examination of metals which failed in

service, are requested. In many cases other lines of testing, such

as determination of some of the mechanical properties, are necessary-.

The following tests are cited as typical of examinations which the

division is often asked to make. Many of the requests for such ex- aminations are received from manufacturers and other industrial

sources. Embrittled Dumlvmin

—This alloy is iised extensively in aero- nautical construction. The material examined was in the form of

thin sheets used as covering on an " all-metal " plane. After a relatively short service life the sheets showed areas in which the metal

had become so brittle that it would crumble in the fingers. The deterioration consists in an intercrystalline attack by which the " bond " between adjacent crystals is destroyed, although the body of the

crystal is not appreciably affected. Corrosion appears to be one of

the fundamental factors by which such embrittlement is produced.

Other causes for this condition Avill be sought.

Brittle Platinum.—A somewhat similar case of embrittlement was

observed in a platinum crucible submitted to the Bureau for examination. Analysis showed that the material contained a small amount

of tin. This exists in the platinmn as a compound of the two metals

in the form of films enveloping the grains to a large extent, and thus

accounts for the brittleness of this platiniim.

Niclxl Anodes.—Anodes for use as a source of nickel in electroplating should contain a considerable amount of graphitic carbon.

It not only aids in the casting of the anodes, but permits them to

corrode much more uniformly than is the case when the carbon content is low. The examination of several typical anodes showed that

the unsatisfactory' behavior of those low in carbon was apparently' the

result of intercrystalline films, presumably of an oxide nature. The

dissolving of this film allows crystals of the metal to be removed
244 KEPOKT or DIRECTOR OF BUREAU OF STANDARDS.

bodily, thus adding to the amount of " sludge " and to the roughness

of the deposit.

Brazed Joints for SJieet Copper.—An examination of different

types of brazed joints showed a simple '• lap " joint to be superior in

mechanical strength and structure to a "lock" joint. The longer

period of heating which the latter type requires for causing tlie "braze" to penetrate the joint often overheats and burns the top

fold of the "lock" so that inferior properties result. The adjacent

metal of the sheet is also much more apt to be affected than is the

case with the simpler joint.

Antique Armor.—Several specimens of fifteenth century chain and

mail armor were examined for the Metropolitan Museum of Art.

The examination indicated that the steel was made by a process very

similar to that used at present for wrought iron. The material was

afterwards carburized, hammered into shape, and often plates of

different hardness were welded together so as to present a hard outer

surface and softer backing. The material was finally quenched in

order to harden it. Oxijacetylene Cutting of Steel.—Two important features examined

in connection Avith this process were the surface hardening, which

nearly always occurs, and the production of cracks in such pieces.

The process of surface hardening by the " quenching action " of the

relatively cool interior upon the hot surface has been patented and

is used successfully in hardening the surface of many small complex

shapes which, because of their shape, would not stand the ordinary

quenching. The cracks resulting from oxyacetylene cutting appear

to be found more frequently in large sections than in small pieces.

The character of the steel also appears to play a part.

Graphitisation in Steel.—The examination of some high-carbon

steel (tool steel) submitted showed that the material had been spoiled

in annealing, so that approximately 0.5 per cent of graphite was

present. This, of course, rendered the steel unfit for any purpose for

which tool steel is used.

^Velded Steel Tubes.—The fact was brought out by the examination of specimens of welded steel tubes that for satisfactory behavior

in the welding machine a steel of low carbon and sulphur content

was desirable. Steel of a somewhat higher content of these two

elements, also containing considerable slag, gave Y&vy unsatisfactory

welds under the same conditions.

Duplex Metal Sheets.—Several examples of sheets of German origin in which the outer layers were of either copper or nickel firmly

welded (by rolling) to the steel base were examined. The sheets are prepared by rolling the required number of billets superimposed one

upon the other. It is necessary that they be protected in a suitable

manner during the necessary preliminary heating. Bullet jackets

consisting of a soft steel base with thin outer coatings of cupronickel

prepared in this manner were used during the recent war by the

German forces.

Wrought Iron.—One of the best criteria to use in deciding Avhether

a product should be classed as steel or as Avrought iron is the examination of the structure. Numerous sjjecimens have been submitted

for this examination.

Locomotive Crwnh Pin.—The examination of a locomotive crank

pin, the failure of which was the cause of a railroad wreck, showed
EEPOET or DIEECrOR OF BUEEAU OF STANDAEDS. 245

that the material had failed by " fatigiie." The material complied

in its mechanical properties with the specifications under which it was purchased. It was shown, however, that by a very simple heat

treatment the elastic properties of the steel could be very materially

improved withoTit a corresponding decrease in ductility, and also

that the structure of the steel would be put into the best condition

possible. This would serve to lengthen the life of the crank pin very

materially when subjected to " fatigue stresses."

• Steel from a Condemned Marine Furnace.—The material was submitted by the Steamboat-Inspection Service for the purpose of obtaining evidence as to whether or not the inspector was justified in

condemning the furnace. The examination revealed numerous fis- sures which had developed on the " waterside " in certain portions of

the boiler. The tensile properties of the steel had not yet been

seriously alfected, although other tests, particularly cold-bending,

showed that the material had been materially affected in its properties. The production of the " fissures " was progressive in character, so that it appeared to be impossible to say when they had

progressed to such an extent as would render the material entircl^^

unfit for use. The results of the examination, on the whole, justified

the inspector in the action taken.

Satisfactory Materials.—It sometimes happens that a metallographic examination reveals the fact that the material is entirely

satisfactory, -in which case it is evident that the cause of the unsatisfactory service must be sought elseAvhere, usually in operating conditions. Materials submitted illustrating this point were boiler

tubes showing peculiar corrosion pits and a cast-iron boiler section

which developed cracks in service.

Working of Metals.—The rolling and forging equipment of the

Bureau is quite often called upon to produce material for various

sections of the Bureau and other Government departments. Among

the work of this character performed during the past year the following may be mentioned : Forging of nickel, forging of invar, cold

rolling several hundred small sheets of steel for paint tests which

could not previously be readily pickled, rolling spring steel, rolling

very thin material as phosplior bronze, manganin, aluminum, etc.. rolling experimental alloy sheets for the Navy Department.

Fusible Boiler Plugs.-—There were tested during the year 578

fusible boiler plugs, 546 being tested for the Steamboat-Inspection

^Service. 23 for the Panama Canal, and 9 for the Interstate Commerce Commission. Of these, 140 were rejected, 72 on account of

the copper content being more than 0.3 per cent, 48 on account of

the copper content being more than 0.3 ]Der cent and the lead content more than 0.1 per cent, 14 on account of the lead content beingmore than 0.1 per cent, 2 on accoimt of copper content being more

than 0.3 per cent and the zinc content being more than 0.1 per cent,

2 on account of iron content being more than 0.1 per cent, 1 on ac- count of the antimony content being more than 0.1 per cent, 1 on

account of the casing not being bronze, and 3 on account of failures

in mechanical specifications. Eleven plugs were reported as having

loose fillings.

Miscellaneoiis Tests.—During the year miscellaneous tests have

been made upon bearing metals submitted by manufacturers, also a
246 REPORT OF DIRECTOR OF BrRRATT OF STANDARDS.

bearing grinding- compound, knitting-machine needles, aluminum

solders, cast aluminum alloys, special process treated steel, transverse

tests on cast iron, -wear tests on carbon and molybdenum steels, soldering fluxes, and brazed copper sheets.

Table of Tests.—In the past year a great variety of tests were made

of various metals and alloys for other sections of the Bureau, Governmental departments, and the public. As sho-wn by the accom- panying table, there was a total of 5,588 tests, the estimated value

for the total number being $16,690.

Tests completed during fiscal year 1921.

Heat treat- ment and

thermal

analysis.

MetalloKi-aphie (including

physical, chemical, and

corrosion tests). Fusible

Castings.

Total.

Irons and

steels.

Nonferrous meta.sIrons and

steels.

jAlumi-

' num

alloys.

Brass and

bronze.

Miscellaneous.

plugs. Ferrous.

Nonfer- rous.

For the Government:

2 2

Foreitcn and Domestic

Commerce 1 1

Bureau of Standards 1,8.525

.50 158 2 7 54 168 1,769 4,060 Navy DeDartment 5 Panama Canal 10 1 23 34 Steamboat-Inspection

Service 4 546

" f"

550 War Department 37.5 5 2 12 394 Post Office Department 1 1 Interstate Commerce

1 1 Coast and Geodetic Sur- vey 405 405 Treasury Department 1 1

4 National Advisory Committee for Aeronautics 4 U. S. Railroad Administration 38 38 Congressional Library 1 3 4

Total 2,232 50 220 3 12 56 569 168 2,190 5,500 For the public 14 1 67 2 4 88

Grand total 2,246 51 287 5 12 60 569 168 2, 190 5,588

Circulars of Information.

The Structure and Belated Proj^erties of Metals.—During the past

year a circular bearing the above title and summarizing the Bureau's

experience in the study of the structure of metals has been prepared.

The circular is a comprehensive one, and such features as methods for

revealing structure of metals, conditions alfecting structure, effects

of structure upon properties, and applications of the microscopy of

metals are discussed in detail and illustrated by means of numerous

references to materials which have been submitted at different times

to- the Bureau for examination and test. The " practical " application of the microscopy of metals has been constantly kept in mind,

and it is anticipated that the circular will serve a very useful purpose

in answering many of the numerous requests for information along

this line which are received.

MetallograpMc Testing.—The circular describing the different

lines of investigation and tests for which the Metallurgical Division
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 247

is equipped has been revised and enlarged. The circular has been

submitted for publication and will soon be available for distribution.

Nickel.—The circular on nickel (No. 100) has been issued during

the past year. This circular includes information concerning the

manufacture, chemistry, metallurgy, and physical properties of

nickel and some of its alloys.

Cooperation with Technical and Scientific Organizations.

The Metallurgical Division has continued, through committee

memberships of various members of its staff, active cooperation with

various scientific and technical societies and groups interested in

metallurg}^. Among these groups which are carrying on active

research may be mentioned the various committees of the American Society for Testing Materials, the Joint Committee on the Investigation of Sulphur and Phosphorus in Steel, the Committee

Advisory to the Bureau on Nonferrous Alloys, National Research

Council, and Engineering Standards Committee. There is in formation a committee on iron and steel representative of these industries. There is also in formation a committee for the investigation

of welding under street-railway conditions. The formation of a research group is contemplated to study in a comprehensive and systematic manner the various fundamental and ^practical aspects of

the corrosion problem. Preparations are being made for the editing of a critical table of physical-chemical constants on the advisory

board of which the Bureau is represented by the chief of the Metallurgical Division.

ommittee on Sulphur and Phosphorus in Steel.—The steel manufacturers, on the one hand, as represented by the Association of

American Steel Manufacturers, and the specification-making bodies,

on the other, such as the United States Railroad Administration and

the American Society for Testing Materials, as well as the Bureau of

Standards, have recognized for some time the urgent nec&ssity of

revision of the requirements as to the content of sulphur and phosphorus in various grades of steel. The present specifications are

largely a matter of tradition and based on fuel and ore conditions

which existed several decades ago. In view of the questions of life

hazard involved in the use of steels for various purposes, the specification-making bodies are loathe to change the sulphur and phosphorus requirements without further experimental evidence. ' There was, therefore, formed on June 23, 1919, a joint committee

for the investigation of sulphur and phosphorus in steel with the

Bureau of Standards (Dr. George K. Burgess as chairman), and

made up of representatives from the 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 and Marine

Engineers, National Research Council, Association of American Steel

Manufacturers, Steel Founders' Association of America, and American Foundryman's Association. A systematic program of investigation has been laid out and excellent progress has been made in its

execution, involving very extensive work in the Government laboratories at Annapolis experiment station, Watertown Arsenal, and the

Bureau of Standards, as well as extended service tests, and the most
248 BEPOKT OF DIRECTOR OF BUREAU OF STANDARDS.

hearty cooperation on the part of the steel manufacturers who are furnishing the materia] under the supervision of the joint committee.

The manufacturers have already spent several thousand dollars in

producing material for the committee, and the expense of testing is

being borne by the several Government laboratories and institutions.

Committee Memberships.

The metallurgical division cooperates with various committees as follows: The National Advisory Committee for Aeronautics, National Eesearch Council, American Institute of Mining and Metallurgical Engineers, American Society for Testing Materials, Joint

Committee on Sulphur and Phosphorus in Steel, American Physical

Societj", Engineering Standards Committee, Society of Automotive

Engineers, American Society for Steel Treating, Reclassification

Committee, and with the Advisorj^ Committee on the Critical Table

of Constants.

Exhibit.

There was shown at the Convention of the American Steel Treaters' Society the week of September 14, 1920, an exhibit illustrative

of the various lines of metallurgical work in which the Bureau is

actively engaged, the exhibit consisting of the work of the several

sections of the division, which was shown by means of photographs,

typical specimens, and apparatus.

Conferences.

There have been held at the Bureau during the past year two semiannual meeting of the advisory committee on nonferrous allo^'S, on

November 10 and April 20, respectively. Among the subjects discussed are the following: Specifications for hard-drawn brass wire,

modifications of a mercurous nitrate test, cadmium plating, standard

chemical samples, bearing metals and solders, casting light alloys on

to steel, material for annular safety release for high-pressure containers, aluminum alloys for all metal airplane covering, molding

sands, improvement in refractories, gases in metals, corrosion, variations of 88-10-2, expansion, spectral analysis, fatigue, and magnetic

properties.

A conference was held with respresentatives of the manufacturers

of chilled-iron car wheels at which the results of the Bureau's investigation of thermal stresses in chilled-iron wheels were discussed. The

manufacturers are much interested in this work, which they believe

will assist them in improving the quality of chilled-iron wheels and

in indicating where the design may be improved. They requested

that the publication of the results be withheld until they have had

time for their further analysis.

Correspondence and Travel.

During the year members of the metallurgical staff have had.opportunity to attend various conferences on technical and scientific

subjects.

Illustrative of the varied requests for information on technical

and scientific subjects there is given below a list of topics of corre- spondence for the month of June, 1921 : Specifications for S. A. E.
EEPOKT OF DIRECTOE OF BUREAU OF STAKDAEDS. 249

bronzes, process of babbitting boxes, seasoning of steels, commercial

grades of Monel metal, yield point of Monel, hardening copper,

standard shrinkage test for cast iron, disapore brick, standard

method of sampling pure aluminum, manufacture of 18 B. and S.

solder, steel for saw frames, breakage and heat treatment of rock

drill steels, Government bronze, tempering of aluminum, stopper

brick, duralumin, X rays in study of structure of metals, fusible

plugs, aluminum, manufacture of steel, electrically hardened lead,

high-speed and carbon twist drills, corrosion of aluminum alloys,

tensile strength of steels at various temperatures, merits of aluminmn

and copper tubing, welding of steel, gases in steel, deoxidation of

steel, corrobility of chromium steels, metals for wash boilers, etching

reagents, galvanizing lead magnesium allo^/, failure of iron pipe,

protection of molds from hot metals, stainless steel, automobile headlight specifications, niagnalite, diaphragms, compression test for

bronzes, method of test for bronze-bearing metals, failure of chilled

cast-iron freight wheels, welded rail joints, Mendall metal, tensile

properties of structural alloy steels, manufacture of tin plate, brazed

copi:>er sheets, substitutes for tin foil, copper roofing sheets, white

metal bearing alloy, steels for boiler tubes, bright annealing, aluminum cable, working of 35 per cent nickel steel, effect of zinc plating on the ph3'sical properties of streamline wire, corrosion of duralimiin,

and methods of welding practice.

Publications.

Publications by members of the metallurgical staff appearing

during the year are as follows: .

Steel rails tVom sink-liead and ordinary ingots (G. K. Burgess), Tech. Paper

178; also Chem. and Met. Eng. (November, 1920), 23, pp. 921-5, 969-75,

1017-22.

Governmental research (G. K. Burgess). Transactions lloval Canadian Inst., Toronto, V. XIII, No. l^; also Scientific Monthly. Octol)er, 1920, pp. .341-3n2. The m.croscope and the heat treatment of steel (G. K. Burgess), yearbook Am.

Iron and Steel Inst, 10 (1920), pp. 1.54-173. Results of tests of centrifu.^ally cast steel (G. K. Burgess), address before

Am. Soc. for Steel Treatiiis, Philadelphia Chapter, Feb. 16, 1921; Transactions of Society, 1, p. 370. 1921.

Properties of steel at I'igh temperatures and their relaticjn to heat treatment

(G. K. Burgess), address before Am. Soc. for Steel Treating, Washington

Chapter, Mar. 18, 1921.

The metallurgical work of the Bureau of Standai'ds, address before American'

Society for Steel Treating. Cleveland Chapter, Feb. 25. 1921, and before

Leh gh Chapter, Bethlehem, Pa., October IS. 1920.

A study of the relation between the Erinell hardness and the ?:rnin size of

annealed carbon steels (H. S. Rawdon and Emilio ,Timeno-Gil, University of

Oviedo. Spain), Sci. Paper 397. The use of ammonium persulphate for revealinsj the macrostructnre of iron

and steel (H. S. Rawdon), Sci. Paper 402; also Iron Aae, v. 106, p. 90.5 (October, 1920).

Electric-arc welding of steel: I. Properties of the arc-fused metal (H. S. Rav/-

don, E. C. Groesbeck, and L. Jordan). Tech. Paper 179. Physical propei'ties of arc-fuspd steel (?I. S. Rawdon. E. C. Groesbeck, and

L. .Jordan ) , Cbem. and Met. Eng. 23, p. 677-84.

Metallofiraphy of arc-fused steel (H. S. Rawdon, E. C. Groesbeck, and J^. Jor- dan), Cbem. and Met. En.s;., 23, p. 777-84.

Notes on electric weMing (H. S. Rawdonl, l\rech. Eng., 42 (1920), pp. 567-.571

reprinted in Electric Railway Ens;., 11 (1920), pi). 441-446.

Metallographic etching reasrents CI), for Copper (H. S. Rawdon and Marjorie

G. Lorentz), Sci. Paper 399.
250 REPORT OF DIRECTOR OF BUREAU OF STAISTDARDS.

Some types of noiiferrous corrosion (H. S. Rawtlon), Trans. Am. Elec. Soc, 38

(1921, corrosion symposium).

The presence of internal fractures in steel rails and their relation to the

behavior of the material under service stresses (H. S. Rawdon). symposium

held by Faraday Soc. (London), April, 1921; Jour, of Faraday Soc, 1921;

reprinted in Eng. (London), 111. p. 470. Some observations on season cracking (H. S. Rawdon). contribution to dis- cussion of " Season cracking of brass," .Tour, of Inst, of Met., 25. 1921.

The thermal characteristics of arc-fused steel (H. S. Rawdon), contribution

to discussion of " Heat treatment of arc welds." Welding Eng., 6 (May,

1921), pp. 44-^6.

Macroscopic examination of metals (H. S. Rawdon), Chem. and Met. Eng.,

24, pp. 385-7.

Preparation of small specimens for microscopic examination (H. S. Rawdon),

Chem. and Met. Eng., 23, pp. 475-6.

Effects of metallic structure upon properties (H. S. Rawdon). Chem. and Met.

Eng., 23, pp. 523-7.

The structure and related properties of metals (H. S. Rawdon), address Am.

Soc. Steel Treating, Philadelphia Chapter (May 27. 1921), Transactions of

the Society, 1 ; 1921.

The use of X rays in the examination of steel (H. S. Rawdon), Metal Heating,

1, pp. 14-18 ; reprinted from 1919 Yearbook of Am. Iron and Steel Inst. Welding practice (H. S. Rawdon), Letter Circular VIII-S.

Experiments in copper crusher cylinders (A. I. Kryuitsky). Tech. Paper 185. The high temperature treatment of high-speed steel and its relation to secondary hardening and to red-hardness (H. Scott), Sci. Paper 295; also Transactions Am. Soc. for Steel Treating, 1, pp. 511-26: 1921. Thermal and physical changes accompanying the heating of hardened carbon

steels (H. Scott and Gretchen H. Movius), Sci. Paper 396. Motion pictures in the mechanical testing laboratory (H. T. French), Chem. and

Met. Eng., 24, p. 131 ; 1921.

Review of recent Japanese metallurgical investigations (H. J. French), Chem.

and Met. Eng., 24 ; Microstructure of chromium steels, pp. 703-6 ; Recent

work on chromium-tungsten steels, pp. 573-5 ; Structui'e of Tungsten Steels, pp. 745-8.

New deoxidizers for steel manufacture (J. R. Cain), Chem. and Met. Eng.,

23, pp. 879-802.

Some properties of white metal-bearing alloys at elevated temperatures (R. W.

Woodward and J. R. Freeman, jr.). Tech. Paper 18S; also Jour. Soc. Auto.

Eng. V. VIII, p. 149 ; February, 1920.

Recent developments in light aluiuinum alloys (R. W. Woodward), Report

of National Advisory Committee for Aeronautics, 1920.

Sources of information and data on metals and alloys (R. W. Woodward),

Letter Circular VIII^, revised edition.

Cast iron for locomotive cylinder parts (C. H. Strand), Tech. Paper 172. Nickel (P D. Merica). Circular 100; also Chem. and Met. Eng. 23 (1921),

pp. 17-21, 73-6, 197-200, 291-4, 37.5-8, 558-60, 649-53.

Aircraft steels, discussion of Prof. Sauveur's paper (G. K. Burgess). Trans.

Am. Ins. of Min. and Met. Eng.. 62, pp. 339-340 ; 1920.

Prevention of columnar crystallization by rotation during solidification (Howe

and Groesbeck), Trans. Am. Ins. of Min. and IMet. Eng. 62, pp. 341-346;

1920.

Mechanical properties of steel at elevated temperatures, below the critical range (H. J. French), contribution to discussion of "Comparative tests of

steels at high temperatures Proc. Am. Soc. for Test. Mate. ; 1921.

The following are publications in press:

Tlie manufacture and properties of steel plates containing zirconium and other

elements (G. K. Burgess and R. W. Woodward).

Thermal stresses in chilled iron car wheels (G. K. Burgess and R. W. Woodward )

Tests of centrifugally cast steel (G. K. Burgess).

The structure and related properties of metals (H. S. Rawdon), Circular 113. Metallographic testing, revised edition (H. S. Rawdon), Circular 42. The effect of phosphorus upon the structure of low-carbon open-hearth steels (E. C. Groesbeck).
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 251

The structure of luetals and alloys (H. S. Ravvdon), American Machinist.

The effect of heat treatment upon the properties of one per cent carbon steel (H. .r. French and W. G. .Tohusojj).

The elements of heat treatment of steel (H. J. French), American Machinist.

An instrument for measuring the elongation of broken tensile specimens

(K. W. Woodward), Chem. and Met. Eng.

Properties of metals and alloys (R. W. Woodward), American Machinist.

Some meehanical properties of moiiel metal (P. D. Merica and R. G. Waltenberg), Proc. Am. Soc. for Test. Mat., 1921.

The erosion of macliine-gun barrels (W. W. Sveshniboff), Tech. Paper 191. Note on the properties of antimonial lead (.T. S. Hromatko and L. J. Gurevich),

Chem. and Met. Eng.

Effect of temperature, deformation, and rate of loading upon the tensile propfti-ties of low-carbon steels (H. J. French).

Experiments on the artificial seasoning of gage steels (H. J. French), Chem.

and Met. Eng.

The intercrystalliue embrittlement of soft metals as a result of corrosion

(H. S. Rawdon. A. I. Krynitsky, and .J. F. T. Berliner).

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 received but limited systematic technical study, the prosecution of researches tending to assist in the more rapid expansion of these industrial activities is of con- siderable importance.

CLAY PRODUCTS.

High-Fire Porcelain Glazes.

This investigation was undertaken for the purpose of supplying

needed information on high -fire porcelain glazes of the Seger cone

type, maturing between cones 12 and 16, the available information

as to compositions suitable for commercial application in the manufacture of such materials as chemical porcelain, spark plugs, and

pyrometer tubes, and on the softening points of various glazes of

this class being extremely meager. Important information has been

gained, including the limits of composition for glazes of this type.

A report of the results is in process of publication as a technological

paper.

Earthenware Bodies and Glazes.

Although much attention has been given to the prevention of the

crazing of j)ottery, this trouble still appears at intervals, and the loss

is sometimes exceedingly heavy. In view of this condition, a further

study of problems related to crazing has been made, with sj^ecial

attention to the composition of tj'pical i^otterj? bodies and glazes.

Results indicate that probable variations occurring from time to

time in the silica content of the clays in the bodies would not be

sufficient to account for the occasional recurrences of crazing. It Avas

found that a modification of the glaze composition by decreasing the

sodium oxide or feldspar and increasing calcium oxide or by substituting silica for feldspar has the eirect of reducing the crazing tendency. The lowest softening points were obtained when the refractory portions of the glaze were included in the frit, but this procedure had no apparent effect on the crazing.
252 REPOBT OF DIRECTOR OF BUREAU OF STANDARDS.'

Solubility of Some Feldspar Frits.

A large range of feldspar frits for, earthenware glazes has been

studied to determine the limits of composition within which frits

of sufficiently low solubilit}' to prevent loss during the grinding and

at the same time of proper fusibility could be obtained. The results

of t^e investigation have been prepared for publication.

Properties of Foreign and Domestic Ball Clays.

The question of suitable ball clays has become one of genuine con- cern to American potters and other manufacturers of ceramic products in which ball claj's are used. English ball clays are still depended on to a considerable extent, although the supply is becomingmore uncertain, the cost is excessive, and the quality somewhat

variable. A considerable number of good American ball clays are

available, but at present the information as to how their properties

compare with those of the English ball clays is not sufficient to enable

manufacturers to make substitutions with satisfactory assurance as

to results. In order to assist in improving this situation, the Bureau

is making a study of the properties of a large number of commercial

ball clays, both foreign and domestic. The work includes the determination of water, of plasticity, drying and burning behavior,

maturing temperature, viscosity of slip, bonding power, and color

effect in porcelain bodies. This work is nearing completion.

Hopi Indian Pottery.

The pottery made by the Hopi Indians is fired in an extremely

crude way, resulting in high loss due to its fragility. The proper

temperature for firing this material in order to produce sufficient

strength without destroying the delicate natural coloring of the ware

has been determined. A more reliable and vivid stain has been

developed for the decoration of this ware. Similar work has also

been done for the Zuni Indian School.

Hardness of Glazes.

The question of the hardness of glazes is of particular interest to

the manufacturers of white ware, as the hardest glazes would

naturally be those most registant to knife marks. The hardness of

a number of typical glazes for porcelain and chemical ware was

studied. The effects of variations in heat treatment as well as in

the composition of the glazes were determined. Increase of firing

temperature increased hardness. Porcelain glazes were found to be

the hardest and white-ware glazes and enamels the softest.

Development of a Satisfactory Chrome-Tin Matt Glaze Maturing

Between Cones 04 and 01.

The use of combinations of the oxides of chromium and tin for

the production of red glazes is common practice, but the results tend

to be erratic. In the case of wall tile uniformity of color is especially

important. In the work done a number of promising combinations

have been developed. Washing the saggers with the glaze has been

found to be essential to satisfactory results.
KEPOKT OF DIRECTOE OF BUREAU OF STAJ^rD.\RDS.

The Effect of Replacements of Sand Flint by Cryptocrystalline Flint

in Pottery Bodies.

Certain troubles in pottery manufacture are attributed to the sand

flint used in the pottery bodies, and it is of importance that the

effect of the replacement of this material, either Avholly or in part,

by other available materials should be determined. The possibilities

of the so-called cryptocrystalline flint which is available in large

quantities in southern Illinois are being investigated. A large

amount of work has been done, but the data are not sufficiently complete to justify conclusions.

Safe Rate of Water Smoking.

Clays and shales of various types were studied to determine their

behavior in water smoking after dilferent drying treatments. The

temperature range of water smoking was found to lie between 100°

0. and approximately 225° C. Results indicate that 12° C. per hour

should be a safe rate of progress during the water-smoking period

for such products as building and paving brick, assuming good ventilation or draft in the kilns.

Casting of Terra Cotta.

A study of the possibilities of the casting process for improving

the quality or reducing the factory cost of architectural terra cotta

has supplied information to the effect that very few of the terracotta bodies now in use possess good casting properties. They could,

of course, be modified by a suitable substitution of clays, but this

would probably involve increased cost of materials in some cases. The mechanical difficulties to be encountered appear somewhat formidable and make the extensive application of the casting process

in this industry of doubtful practicability at the present time.

Effect of Time of Drying on Total Shrinkage of Clays.

A number of typical shale ball clays and fire clays were studied.

Under laboratory conditions, increasing the drying temperature at

different rates to a maximum of 100° C., it was found that the re- quired drying time depends largety on the water content and the

structure of the clay, but that the total shrinkage is independent of

the drying time.

The Use of Special Oxides in Porcelain Bodies.

The investigation includes a study of the results obtained with the

oxides of zirconium, thorium, and titanium and the rare-earth oxides

of cerium, lanthanum, and didymium and tlie silicate of zirconium.

Drjdng and burning behavior, color, structure, mechanical strength,

and dielectric resistance were determined for bodies in which these

oxides were substituted for flint. Zirconium oxide produced the best

porcelain from all standpoints, while the zirconium silicate body

tended to overfire easily when used in combination with feldspar.

The rare-earth oxides proved undesirable in every way. Thorium

and titanium did not prove satisfactory. None of the oxides affected

the dielectric resistance. Some very satisfactory bodies for pyrom-
254 REPORT Oli' DIRECTOR OF BUREAU OF STANDARDS.

eter tubes, cooking ware, and electrical heating devices were developed. The results of this investigation are being compiled for publication as a technologic paper.

Cooperative Investigation of Problems Relating to Architectural

, Terra Cotta.

A large amount of work in this investigation has been made possible by the cooperation of the National Terra Cotta Society. In

addition to a continuation of the laboratory Avork at the Bureau, an

extensive program of field observations on the condition of terra

cotta in buildings under different conditions in various parts of the

United States and Canada has been carried out. In the laboratory

a large amount of work has been done in correlating the porosity and

absorption of different bodies burned to a number of different temperatures with the tensile strength, in addition to the transverse re- sistance and the resistance to sodium sulphate treatment and to ac- tual freezing. Expansivity measurements have been made on a considerable number of bodies and glazes in connection with the question of glaze fit and the role played by glaze composition in the

failure of terra cotta. Work has been started in the study of the

effect of the rate of cooling on the subsequent resistance of terra

cotta to temperature changes and other agencies.

OPTICAL GLASS.

Scope of Work.

The work of this section covers the (1) making of optical glass;

(2) the molding of optical shapes, such as lens blanks, prisms, etc.,. from such glass; (3) the annealing of glass; and (4) the improvement and development of specifications for raw materials and for

finished optical glass, as well as commercial glass for various industrial uses. Melting.

During the past year this section has made 33 experimental melts

of various kinds of glass, repi'esenting about 30,000 pounds, including borosilicate crowns, light and dense barium crowns, ordinary

and barium flints.

Molding.

Considerable progress has been made in the development of a satisfactory technique in the molding of moderately large lens and

prism blanks by the " sticking-up " process. Blanks for 3-inch rightangled prisms, which would be difficult to mold by the usual paddling process, have been successfully molded by this process, and

troubles with cracking, folds, etc., have been largely eliminated. Experimental work on the making of large slabs and disks by meltingdown rough pieces of optical glass in clay molds has been continued.

Disks for lenses of approximately 15 inch diameter have been made

and equipment for molding larger disks has been installed. ; Annealing.

Scientific work of the Bureau of Standards on the annealing of

glass has previously been reported. The findings of this investiga- i tion have been applied during the year to the annealing of optical

glass of different kinds in various sizes and shapes. The results
REPOBT OF DIRECTOR OF BUREAU OF STANDARDS. 255

indicate that the problems inAolved are more complex than has

previously been realized.

Due to the necessity of precise control of temperature conditions in

furnaces for the fine annealino; of pieces of even moderate thickness

it has been found necessary to design an electric annealing furnace of

considerable size with provision for automatic temperature control.

This furnace is in process of installation.

Optical Glass for Navy Department.

One of the fundamental purposes of the optical glass section is to assure the availability of optical glass for scientific and military

purposes from domestic sources. In the course of experimental

work on types of glass suitable for militar}^ optical instruments considerable quantities of glass of the highest quality are produced, and

a large proportion of such glass is sup])lied, by special arrangement,

to the Nav}' Department in the form of molded blanks and slabs.

During the past year these deliveries have amounted to slightly more

than 1.500 pounds, distributed as follows : Two hundred and eightysix medium flint lens blanks, 11-1: pounds; 1,758 light barium crown

lens blanks, 823 pounds; 1,357 borosilicate crown prisms, 450 pounds;

slabs and miscellaneous shapes, 672 pounds.

In addition to this the special requirements of the Bureau of

Standards for optical glass for use in research work have been

supplied.

Investigation of Colored Glass.

In addition to investigations incident to the manufacture of

optical glass for lenses, prisms, etc., the development of colored

glasses suitable for screens for use in naval telescopes and similar

instruments is also receiving considerable attention. Promising

results have recently been obtained from the work on neutral glasses

for this purpose.

Specifications.

The preparation of specifications for the purchase of glass articles,

such as tableware and sheet glass, by the various Government departments has been undertaken by this section. This work has progressed to the extent of obtaining the opinion of numerous manufacturers and dealers as to what such specifications should comprise

and obtaining samples for test.

Cooperation.

This section is cooperating with the interdepartmental conference

on chemical lime in the preparation of specifications for lime to be

used in glass manufacture. The specifications have been drafted and

submitted to representatives of interested technical societies and

manufacturers for approval.

Information.

Numerous requests for information relative to the various phases

of commercial and optical glass manufacture are being received.

The information requested includes opinions as to the quality of raw

materials used in glass making, formulae for various kinds of glass,
256 REPORT 0¥ JnRECTftR OF BUREAU OF STANDARDS.

methods of manufacture, coloring agents, annealing, causes of vari- ous defects, testing, etc. In order to facilitate answering some of

these inquiries and to furnish more detailed information, material

for a publication regarding the manufacture of commercial glass

has been collected.

REFRACTORIES.

Transverse Strength of Fire-Clay Tile.

Reliable data on the transverse strength of fire-clay tile have been

greatlj^ needed by furnace designers. Such data have now been

made available by transverse strength tests of tile at various temperatures. Tests were made on tile obtained from a number of

manufacturing districts in different parts of the country, and these

were supplemented by tests of tile made in the laboratory. A fairly

good conception of what can be obtained in the way of strength from

fire-clay tiles of moderate thickness supporting loads over bridged

gaps may be gained from the following figures, which give the

average modulus of rupture of all the commercial tile tested for each

of four temperatures. None of the brands tested gave results suffi- ciently high to exclude them from the conclusions to be drawn from

these data, and none of the tile made in the laboratory gave promise

of the attainment of great improvement on these values by the use of special mixtures of fire clays and fire clay grogs. Temperature

(centigrade), 1,275, 1,300, 1,325, 1,350; modulus of rupture (pounds

per square inch), 245.5, 98.7, 54.2, 29.5.

These results obviously indicate an extremely rapid falling off of

strength above 1,275° C, and when the effect of time is taken into

account it becomes evident that the transverse strength above 1,300°

C. is a negligible quantity from the standpoint of design.

Study of Bond Clays for Glass Pots.

A comparison was made between the significant pi'aperties of the

Gross-Almerode clay and a series of mixtures of American bond

clays to determine how closel}^ such mixtures approximate the

nature of the Gross-Almerode clay and whether any of these mixtures when used in a glass-pot body resist the action of a corrosive

glass as well as a body made from the Gross-Almerode clay. None

of the mixtures tried equaled the Gross-Almerode clay in point of

low-water requirement for plasticity and low shrinkage, but some

of the bodies made from American clays resisted corrosion better

than the bodj^ bonded with the Gross-Almerode cla.y.

Combinations of Silsceous Clay with Aluminous Grog Compared

with Reverse Combinations.

This work was done for the purpose of determining the superiority

of one of the two types of glass-pot bodies ; i. e., the type in which

an aluminous grog is bonded with a siliceous clay or clay mixture

and the type in which the grog is siliceous and the bond clay

aluminous. The results indicate the superiority of the former type.

Special Material for Refractory Tubes.

In order to furnish refractory tubes suitable for some special work

under the direction of Dr. Mendenhall, a considerable amount of ex- perimental Avork was done, Avliich resulted in the development of a
REPORT OF DIRECTOR. OF BUREAU OF STANDARDS. 257

body suitable for the making of tubes which has a softening point

of approximately 1,760° C. and resists rapid heating and cooling.

ENAMELS.

Elimination of " Fish Scaling " of Enamels on Iron and Steel.

The tendency to " fish scaling " is one of the most costly and the

least understood of the troubles of the enameler. The Bureau has

made an exhaustive study of this problem and has succeeded in

determining the causes of the tendency and in finding practical

means for correcting it. It has been demonstrated by expansivity

measurements that " fish scaling " is due, primarily, to differences

between the coefficients of expansion of metals and of the enamels

with which they are coated, the enamel being in compression at

ordinary temperatures. A second cause is the poor adhesion of the

enamels to the steel. Suitable compositions of enamel minimize the

difference in contraction of the enamels and steel and are a factor

in increasing the strength of the enamels. It has also been determined that suitable mechanical treatment of the metal previous to

enameling reduces, and in certain cases eliminates, any tendency to

" fish scaling " by providing a better bond. This is in accord with

observation of the behavior of enamels on what is termed " drawn

or spun ware."

Having succeeded in developing practical methods for correcting

the " fish-scaling " tendenc}^, the Bureau has started a program of

cooperation with both metal manufacturers and enamelers for the

purpose of applying these methods on a commercial scale. Metal

stock now being prepared in the mills will be fabricated and enameled

in five enameling plants. It is the purpose of the Bureau to publish

a combined report of this laboratory investigation and the factor}^

application in the form of a technologic paper.

Wet-Process Enamels for Cast Iron.

The dry process of cast-iron enameling is well suited to tlie coating of such large objects as bathtubs and sinks, but is not adapted

to the manufacture of such articles as stove fittings, where the ware

is small and volume production is desired. Actuated by requests

from a number of stove manufacturers, the Biu'eau has uadf>rtaken

an investigation of methods for the production of wet enamels. An

extended study has been made of both ground coats and cover coats

and a number of satisfactory compositions have been developed.

This work is nearing completion.

White Enamels for Copper.

The Bureau has in the past had a number of requests for compositions of enamels and information regarding technique for the

enam.eling of copper. While it has not been possible to make an

extended investigation of this subject, some 20 compositions have been

studied. Several of these are promising. Essential knowledge as to

technique has been gained. The results of this work will appear in

a paper in a forthcoming number of the Journal of the American

Ceramic Society.

64984—21 17
258 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Relation of Composition of Enamels to Solubility in Acids.

The work on this investigation was completed in the past year and

the results will be published in a forthcoming number of the Journal

of the American Ceramic Society. Some excellent acid resistant

enamels for application to cast iron by the dry process have been

developed and important information relative to the effect of composition on the acid resistance and adherence of this type of enamel

has been obtained.

Replacement of Tin Oxide in Enamels for Sheet Steel.

'Substitutes for tin oxide in enamels are offered from time to time,

and to determine the comparative effect of these substances on opacity

a number of them have been applied in enamels for steel. Another

phase of the problem is the development of a method for establishing definite comparative values for the opacity of the various en- amels. The colorimetry section of the Bureau is cooperating in making these determinations by means of the spectrophotometer. The

preliminary results so far obtained are most promising, and it appears that the instrument could be used to obtain a quantitative figure

showing the value of any substitute as an opacifier alone.

TESTING AND INFORMATION.

One of the functions of the division is the testing of ceramic

materials for the various Government departments and in certain

cases for outside parties. During the jDast year 134: tests on fire

brick have been made for the Panama Canal Commission. These

included fusion tests, endurance of high temperatures under load,

and tests for spalling. Twenty-five tests on refractory materials

were made for outside parties.

Thirty-four reports of preliminary tests on clays submitted were

prepared. These preliminary tests are made for the purpose of

determining whether a material is of such a nature as to justify

a more thorough investigation of its properties.

Twelve feldspars from various sources were tested during the

year with a view to supplying information as to whether the deposits from which they were obtained were of sufficient promise for

further exploitation. A number of those examined proved to be

of excellent qualit}^. This work is of importance because of the fact

that sources of supply of this essential material are somewhat

limited.

In addition to the reports of actual tests the division has been

able to be of service to a number of the Government departments

by supplying information and assisting in the preparation of specifications for ceramic materials. The departments assisted include

the Panama Canal Commission, the United States Geological Survey, the Navy and War Departments, the Department of the Interior, the Department of Agriculture, the Public Health Service,

and a number of State geological surveys.

A large amount of information bearing on specific problems of

manufacturers has been furnished, and in many cases it has been

possible to render assistance in the correction of serious difficulties.
REPORT OF DIRECTOR OE BUREAU OF STANDARDS. 259

Cooperation with Technical Societies.

Through members of its staff the division has participated actively

in the work of the American Ceramic Society, the American Society

for Testing Materials, the National Terra Cotta Society, and the

National Fire Protection Association. A large part of this work is

along the line of the development of standard tests and the establishment of standards for materials and for the construction of

buildings.

Cooperation with Commercial Organizations.

In addition to the w,ork that is being done in cooperation with

the National Terra Cotta Society the division has taken part in the

research on the properties of hollow building tile which the Bureau

is carrying out in cooperation with the Hollow Building Tile Association. Work has been started on the Bureau's part in an investigation in cooperation with an association of heavy clay products'

manufacturers, and arrangements have been made for a cooperative

study of special problems of the Associated Tile Manufacturers.

PUBLICATIONS.

During the year the following reports have been published. A

number of these are in the nature of progress reports and have been

published in outside publications in order to make the information

available as early as possible. Eeports of completed investigations

are published in the form of technologic papers of the Bureau.

Technologic Paper 165, Enameling of sheet iron and steel. Classification of enamels for sheet steel, Jouv. Am; Cer. Soc, 3, No. 12. Note on porcelain glass-pot mixtures, Jour. Am. Cer. Soc, 3, No. 7. The rate of vitrification of porcelain molded under different conditions. Jour,. Am. Cer. Soc, 3, No. 10. Possibilities for research and development in the field of refractories, Chem.

and Met. Eng., Dec. 15, 1920.

Note on tlie effect of time on the drying shrinkage of clays, Jour. Am. Cer. Soc, 4, No. 4. The watersmoking of clay. Jour. Am. Cer. Soc, 4, No. 5. Refractories for electric furnaces, report of meeting of Oct. 6, 1920, of the

Electric Furnace Association.

The solubility and fusibility of some feldspar frits. Jour. Am. Cer. Soc, 4, No. 6. The absorption of sodium hydroxide by kaolins. Jour. Am. Cer. Soc, 4, No. 6.
III. THE OFFICE.

Office management, publications, information, personnel, fund accounts, purchases,

property and stores, mail and files, scientific library, transportation and communication,

tests, ^nd general clerical and secretarial work. GENERAL.

t The activities of the office, briefly stated in round numbers for the

past year, were as folloAvs: General clerical work, secretarial and

office management of the clerical work of the divisions, correspondence, certificates and reports of tests and investigations, and records

pertaining thereto; editorial and proof inspection for manuscripts

submitted for publication, resulting in 110 new publications, approximately 6,000 new pages of printed matter, about 180,000 separate pamphlets ; appropriated and transfer fund accounts for Bureau

expenditures, amounting to nearly $1,750,000; personnel work comprising all changes of staff status and records therefor, involving

about 2,500 personnel changes and a net turnover of 50 per cent of

Bureau staff ; special and regular purchases (for Avhich 15,000 scientific and industrial catalogues are available), involving over 5,000

orders ; accountability records for 155,000 items of inventoried apparatus, machines, tools, and other equipment, including the accession

of 13,000 additional pieces; record and distribution of mail (more

than 175,000 official communications, an increase of 25,000 pieces) ; supervision of the scientific library of 21,000 volumes in the fields

of physics, chemistry, engineering, and mathematics; collation and

furnishing of technical information, issuance of a technical news

bulletin giving industrial experts the results of Bureau investigations, including supervision of the official distribution of Bureau

publications.

FINANCE.

Funds.

The regular api^ropriations of the Bureau amounted to $1,304,632.

Additional items approximating $35,000 were carried in the first

deficiency act and $15,000 of the public utility standards appropriation for 1922 was made immediately available, making a net total of

$1,354,632. There were transferred to the Bureau from other departments for cooperative investigational work, under authority con- tained in the legislative, executive, and judicial act of May 29, 1920,

the sum of $369,992, and reimbursements were also received in the

amount of $16,014.17, making the total available for obligation

$1,740,638.17.

Appropriation Statements.

The following statement shoAvs the amount and object of each

appropriation provided for the Bureau for the fiscal year 1921, the

disbursement during the year, the amount of unpaid orders at the

260
REPORT OF DIRECTOR OF BUREAU OF STA5TDARDS, 261

close of the year, and the unexpended balance remaining at the close

of business June 30, 1921

Appropriation. Total appropriation. Disburse- ments. Liability. Balance.

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5 oij finn nn ouu. uu 9C AQ7 77 ^o, oy /. 1 / 1 nAA Q s; o, UDO. OO Qc; QQ

6" -IDj 1 nn loo. uu An QQQ QQ Q7Q n7 1, 410. oy m nnn nn lUj uuu. uu 7 ns^ti (27

/, UOO. o/ 9 ono 7 c; z, yuy. ( Q/l Qft inlu, nnn uuu. nnuu ^A noi 1Q oo, uyx. ly Q A9^ 1Q .3, D^O. l.J 929 ZfSO. ACDo Investigation of fire-resisting properties 25, 000. 00 21, 184. 99 3, 642. 25 172. 76 Investigation of railway materials 15,000. 00 13,347. 87 1,442.03 210. 10 Testing miscellaneous materials 30, 000. 00 27, 159.60 2, 840. 30 .10 Investigation of public utility standards... 7 85, 272. 86 S4, 725. 81 333.83 213. 22 Radio research 8 30, 096. 00 27,243.57 2,681.75 170. 68 Industrial research 9 419,717. 46 315,219. 21 88, 578. 99 15,919.26 Sound investigation 10 7,000. 00 6, 057. 66 904. 53 37. 81 Clay products 25, 000. 00 22,380. 43 2, 391.08 228. 49 Color standardization 10, 000. 00 9, 069. 35 692. 34 238. 31 Standardizing mechanical appliances 11 35,000. 00 29, 299. 43 5,461.29 239. 28 Investigation of mine scales and cars 15, 000. 00 9,072. 30 3, 692. 50 2, 235. 20 Standardization of equipment 15, 000. 00 5,988.97 3, 623.48 5, 387. 55

Total 1,729, 022. 33 1,458, 592. 01 218, 355. 84 52,074.48

1 Includes reimbursement of $330 received from other departments.

2 Includes reimbursement of $61.01 received from other departments.

3 Includes reimbursement of S6,000 received from other departments.

Includes reimbursement of $680 received from other departments.

s Includes reimbursement of $1,800 received from other departments.

« Includes reimbursement of $6,183 received from other departments.

' Includes reimbursement ol $272.86 received from otiier departments,

s Includes reimbursement of $96 received from other departments.

9 Includes reimbursement of $369,717.46 received from other departments.

i« Includes reimbursement of $2,000 received from other departments. " Includes reimbursement of $20,000 received from other departments.

The following statement shows the condition of the appropriations for the two preceding fiscal years at tlie close of business June

30, 1921

Appropriation.

FISCAL YEAR 1919. Salaries Equipment

General expenses Grounds

High potential investigation

Testing structural materials Testing machines

Investigation of fire-resisting properties .

Investigation of pubHc utility standards.

Investigation of railway materials Testing miscellaneous materials Radio research

Color standardization

Investigation of clay products

Determining physical constants Standardizing mechanical appliances

Investigation of 0])tical glass Standard materials

Total appropriation.

$432,

12 81, " 50,

7, 15,

i< 235,

30, 25,

15 55,

15, 30,

20,

10, 20,

w 84,

4,

360. 00

200. 00

100. 76

500. 00

000. 00

094. 14

000. 00

000. 00

000. 00

000. 00

000. 00

000. 00

000. 00

000. 00

000. 00

000. 00 388.75 j 000.00 I

Disburse- ments.

.$375, 860. 09

74, 745. 24

46,279.93

7, 285. 82

14, 832. 33

224, 088. 76

29, 220. 99

24, 705. 99

54, 505. 08

14, 834. 04

29,690. 20

19, 838. 41

9, 943. 50

19, 766. 44

4,972. IS

9, 9ill. 79

82, 134. 89

3, 833. 24

Liability.

12 Includes reimbursement of $200 received from other departments

1' Includes reimbursement of $100.76 received from other departments. " Includes reimbursement of $110,094.14 received from other departments.

1* Includes reimbursement of $5,000 received from other departments.

1* Includes reimbursement of $64,388.75 received from other departments.

$7. 96

1, 619. SO

3, 093. 55

14.24

21. 19

214. 15

78. 07

357. 21

29. 10

31.43 1.60

986. 38

Balance!

$56, 491. 95

4, 834. 96

727. 28

214. 18

153. 43

11,004. 19

564. 86

215. 94

137.71

136.86 309.80

161. 59 56.50 202.13

26.22

88. 21

1, 267. 48

166. 76
262 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Appropriation.

FISCAL YEAR 1919—Continued.

Investigation ol textiles Sugar standardization Gauge standardization Renewal of storage batteries Military research, 1918-19 Investigation of mine scales and cars, 1918-19 Investigation of public-utility companies, 1918-19 Testing railroad scales

National security and defense. Military researches

Robert's coke oven Thermit investigation Altitude laboratory

Power-plant eqiupment (industriallaboratory)...

Completing laboratories Arma,ment of fortification (commerce transfer)..

Aviation, Navy, commerce transfer

Total

FISCAl TEAR 1920. Salaries Equipment

General expenses Grounds

Testing structural materials Testing machines

Metallurgical research Investigation of optical glass Standard materials Investigation of textiles Sugar standardization Gauge standardization High-temperature investigation

Testing raUroad scales Investigation of fire-resisting properties

Investigation of railway materials Testing miscellaneous materials Investigation of public-utility standards Radio research Industrial esearch, 1919-20 Industrial esearch, 1920 Sound investigation

Investigation of clay products

Color s tandardization Determining physical constants Standardizing mechanical appliances

Investigation of mine scales and cars Industrial safety standards

Testing Government materials Standardization of equipment

Platiniun and rare metals

Retaining wall Equipping laboratory, 1919-20

Total

Total appropriation.

$10, 000. 00

1' 21, 350. 00

18 433, 000. 00

20,000. 00

I'J 622, 690. 48

15, 000. 00

2» 53, 522. 52

21 41, 104. 70

100, 000. 00

40, 000. 00

4, 300. 00

60, 000. 00

31, .500. 00

235, 000. 00

22 224, 333. 03

5, 000. 00

3, 046. 444. 38

486, 760. 00

23 108, 033. 00

95, 000. 00

7, 500. 00

24 150, 718. 25

25 35, 263. 49

26 30, 129. 97

2' 63, 761. 12

5, 000. 00

15, 000. 00

28 21,800. 00

29 56, 276. 90

10, 000. 00

3« 43, 841. 06

25, 000.00

15, 000. 00

30, 000. 00

31 114, 159. 82

32 31, 555. 94

33 71, 899. 23

34 291, 775. 05

35 7, 237. 04

20, 000. 00

10,000. 00

5,000. 00

36 50, 820. 26

3' 15, 179. 73

25,000. 00

38 100, 182. 00

39 52, 292. 00

15,000.00

20, 000. 00

100,000.00

Disburse- ments.

S9, 864. 91

20, 773. 13

426, 935. 68

18, 695. 77

617, 695. 74

14, 714. 67

52, 713. 88

39, 166. 60

97, 362. 15

39, 748. 42

3, 946. 75

59, 897. 19 31,461.01

231, 870. 41

145, 506. 18

4,998. 28

2, 861, 779. 69

461, 871. 34

103, 388. 39

79, 145. 39

7, 397. 95

148, 175. 76

34, 459. 31

29, 102. 44

62, 961. 72

4, 818. 75

14, 840. 44

21,056.34

55, 455. 94

9, 930. 92

42, 839. 09

24,255. 04

14,649. 36

29, 844. 68

112, 043. 91 30,758. 55

69, 994. 12

286,685. 39

6, 876. 72

19, 824. 00

9, 937. 25

4, 996. 00

49, 597. 72

15, 061. 26

24, 459. 32

97, 454. 65

34, 463. 83

14, 982. 23

17, 674. 27 98,010.26

2, 129, 184. 86 2, 037, 012. 34

Liability.

$3. 75

1, 319. 75

'i,'^96.'42' 104. 20

737. 49

220. 60

549. 78

183.01 190.56

4,317. 55

16,077.79

618. 70

3, 972. 66

7, 129. 40 " "995.59'

174. 77

737. 50

450. 00

517. 11

'""oi'.n

206. 06

'is." 50'

1, 525. 43

625. 91

25. 30

2, 884. 56

252. 52

694. 03 12.29 23.00

1, 703. 56

151. 09

960. 28

23,715.57

1' Includes reimbursement of .$1,350 received from other departments.

18 Includes allotment of $283,000 received from War Department.

19 Includes reimbursement of §272,690.48 received from other departments

20 Includes reimbursement of $3,522.52 received from other departments.

21 Includes reimbursement of $1,104.70 received from other departments.

22 Includes reimbursement of $124,333.03 received from other departments.

23 Includes reimbursement of $33 received from other departments.

24 Includes reimbursement of $25,718.25 received from other departments.

25 Includes reimbursement of $5,263.49 received from other departments.

26 Includes reimbursement of $5,129.97 received from other departments.

2' Includes reimbursement of $43,761.12 received from other departments.

28 Includes reimbursement of $1,800 received from other departments.

29 Includes reimbursement of $16,276.90 received from other departments.

30 Includes reimbursement of $3,841.06 received from other departments.

31 Includes reimbursement of $29,159.82 received from other departments.

32 Includes reimbursement flf $1,555.94 received from other departments.

33 Includes reimbursement of $21,899.23 received from other departments.

34 Includes reimbursement of $41,775.05 received from other departments.

85 Includes reimbursement of $2,237.04 received from other departments.

36 Includes reimbursement of $35,820.26 received from other departments.

8' Includes reimbursement of $179.73 received from other departments.

38 Includes reimbursement of $182 received from other departments.

39 Includes reimbursement o£ $2,292 received from other departments.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 263

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 j)rimarily 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, except

when made for the National or State Governments. The number

of tests completed during the year, together with their value, is shown in the folloAving table

Number and Value of Tests Completed,' Fiscal Year Ending June 30, 1921.

. —

Nature of test.

*

For Government. For public. Total.

Number. Value. Number. Value. Number. Value.

Length:

—

«f:7e Qfi DO ion Other length tests Mass:Weights

OVI . i 9 9A7 90 Oj you

1,104 683. 10 4,122 1, 988. 95 5,226 2, 672. 05 Scales and balances 530 21, 027. 50 2 26. 50 532 21,054. 00 2,753 1,188. 45 7,045 3, 407. 35 9,798 4, .595. 80

164 189. 25 475 781. 75 639 971. 00 Time 5, 472 15, 738. 25 54 129. 00 5, 526 15, 867. 25

832 2, 431. 85 628 2, .357. 50 1,460 4, 789. 35

1,805 6, 563. 00 75 235. 50 1,880 6, 799. 50

69 73. 30 2,111 16, 499. 82 2, 180 16, 573. 12 Temperature:

Clinical thermometers 22, 338 1, 838. 53 1,264 143. 48 23, 602 1,982.01 Other thermometers and miscellaneous 1,610 1, 597. 97 2,427 5, 094. 93 4, 037 6, 692. 90 Optical tests: Sugar polarimetry 1,574 1, 587. 80 39 160. 00 1,613 1, 747. 80 Other optical tests 919 857. 00 1,519 2,654. 70 2,438 3,511.70 Chemical analyses: Structurafmaterials 1,070 10, 700. 00 1,070 10, 700. 00 Other materials 6,383 101, 826. 00 6, 383 101, 826. 00 Standard samples 448 837. 65 3,430 fi, 729. 35 3,878 7, 567. 00 Mechanical instruments and appli- 407 1, 722. 00 78 283. 00 485 2, 005. 00 Aeronautical instrument tests 123 1,489. 00 9 51. 50 132 1, 540. 50 Physical tests of materials: Cement 5,274 40, 804. 50 87. 50 5,281 40, 892. 00 Other structural materials 2,015 5, 876. 55 105 400. 00 2, 120 6,282. 55 Miscellaneous materials, includ- ing paper, textiles, ruliber, leather, etc 10, 129 44, 141. 25 538 1,227. 60 10,667 45, 368. 85

611 2,260. 00 23 198. 25 634 2,458. 25

204 2, 688. 25 125 403. 80 329 3, 092. 05

Total 67, 398 267, 505. 85 26, 638 45,259.63 94,036 312, 765. 48

' The tests reported in this table include only the tests for which all technical procedure was entirelj- completed during the year 1920-21.

2 In addition the Bureau inspected 2,849,564 incandescent lamps at various factories for other departments

of the Government, the fees for which would amount to $7,383.60. PERSONNEL.

During the year the Bureau staff averaged 850 regularly appointed

employees—342 statutory employees and about 508 engaged in re- search and investigations specially authorized by Congress. The

statutory positions include 201 scientific positions, 56 office assistants,

50 engaged in the operation of the plant, and 35 in the construction.

The total turnover in the personnel for the year was approximately

50 per cent, of which approximately 30 per cent were actual resignations. The personnel on June 30, 1921, consisted of 870 employees,

a net reduction of 27 employees during the year.
264 RBPOET or DIEECTOE. OF BUREAU OF STANDARDS.

Death of Two Division Chiefs. ^ The Bureau has suffered a severe loss in the death of two chiefs of

divisions, Dr. Edward B. Rosa, chief of the Electrical Division,

and Maj. Louis A. Fischer, chief of the Division of Weights and

Measures.

Dr. Rosa died on May 17, 1921, and Maj. Fischer's death occurred

as this report was beino- prepared. These two officers were seniors

in point of service, entering the Bureau at the time it was created

in 1901. Dr. Rosa was a recognized leader in fundamental electrical

researches and was also prominently identified with the preparation

of national codes of practice and safety in industrial work. He

organized the work of electrical testing, photometry, radio communication, and radio activity, as well as the public-utilities investigations

of the Bureau.

Maj. Fischer stimuLited a nation-wide interest in the subject of

trade weights and measures, and his able cooperation with State and

local superintendents and weights and measures inspectors brought

about the most cordial relations between the specialists in this field

and the Bureau. He also successfully organized the technical sec- tions of the Bureau in charge of measurements of length, mass, ca- pacity, time, pressure, and related subjects.

PURCHASE.

The 5,000 Bureau orders placed during the 3'ear comprised 286

exigency orders, 90 special orders through the Division of Supplies,

and 4,300 regular orders. The purchase office handled 2,222 prol^osals covering the needs of practically every laboratory of the

Bureau following the essential Government routine. A systematic

record of bids and purchases is maintained to aid the Bureau's staff

and facilitate the purchase work. The section also prepared all

formal contracts for larger purchases and enterprises and handled

725 travel authorizations and the records incident thereto.

PROPERTY AND STORES.

This section administers the accession, distribution, and accountability of property, the records of property, both equipment and supplies, and also the work of receiving and shipping instruments and

materials of all kinds, including the packing and shipping of all

instruments tested hy the Bureau. These functions include the

receiving at the shipping room and delivery trucking. With the

new space assigned for the main storeroom, this branch will be

adapted to serve the needs of the Bureau more efficiently.

During the year approximately 60,200 items of supplies and property were received and inspected by the staff in charge of property

and stores. The inventoried items of equipment included 13,400

pieces of apparatus and other equipment. Supplies were dispensed

by the storeroom to the value of approximately $58,000. Approximatel}^ 12|^ tons of instruments and other technical materials pass

through the shipping room per week, and 6 tons of additional transportation is required outside of the shipping room.
REPORT OF DIRECTOR OF BUREAU OF yTANDARDS. 265

MAIL AND FILES.

Volume of Mail.

The volume of mail handled shows an increase of about 25,000

pieces over the previous fiscal year, totaling approximately 175,000

pieces. This number includes only first-class mail addressed to the

Bureau and dictated replies thereto, taking no account of the large

uimiber of incoming and outgoing form letters and incoming secondclass and other mail handled by the mail I'oom, about 100,000 additional pieces per year. Intrabureau communications average about

-500 per day. Of the 175,000 pieces of mail 130,000 are brief indexed.

An automatic index for the files of index slips was installed during

the year and minimized the liability of misfiling.

Model Letters and Clerks' Instructions.

A 53-page " Standard office practice " was issued to the clerks during the year. It contains the general regulations, model forms,

standard modes of address, and samples of the correct usages for

guidance in the preparation of letters and other communications,

certificates of test, manuscripts, and reports. Daily inspection of

outgoing mail as to compliance with standard practice is conducted

by this section. Supplementary to the " Standard office practice " 11 sheets of " Office notes " were issued to the clerks reminding them

of existing practice, approved changes in practice, and new rulings

as to procedure. These have brought uniformity in the clerical work

of the Bureau with excellent results.

''

LIBRARY.

-The work of the librarian includes the maintenance of the

Bureau's collections of scientific and technical books and periodicals

with card catalogues of the same, bibliographical work, selection of

new reference books, preparing book lists for prospective accessions, accessioning of new books, loans and accountability records,

assistance to technical staff in locating sources and data, and the

binding of books and periodicals.

Accessioned Volumes.

At the close of the year the technical library of the Bureau con- tained 21,284 accessioned volumes. Except for a few law books

these are all of scientific and technical character, chiefly in the sub1'ects of physics, chemistry, engineering, and special technology.

)uring the fiscal year 1,998 new volumes were accessioned.

Technical Journals.

The Bureau receives currently 563 scientific and technical periodicals. About one-half of the periodicals are received by exchange.

The technical journals currently received comprise 229 American,

132 British (and others in English), 61 French, 107 German, 34

others, having in all 9,547 parts a year. Besides these, 275 other

nontechnical periodicals, including j^early reports, are received having 1,580 parts, making a total of 11,127 parts handled during the

year.
266 PiEPOET OF DIRECTOR OF BUREAU OF STANDARDS.

Circulation.

Most of the consultation of books is in the library and at points

where desk copies of important texts and reference books are as- signed throughout the laboratories. Besides such regular consultation, however, a monthly average circulation of 600 books and

journals was maintained throughout the year. By a cooperative

arrangement with the various libraries in Washington and outside

491 loans were made to the Bureau. In return the Bureau makes

loans to experts in other institutions and tenders the facilities of its

library for consultation and reference.

INFORMATION.

The information section has charge of the collation and dissemination of technical information, including the distribution of the

scientific and technical papers of the Bureau, which are the most

important means of rendering the results of the Bureau's research

available to the public.

Technical Documents.

Special and confidential documents received at the Bureau and

not deposited at the library have been filed or distributed to the

various scientific divisions as heretofore. The number of such documents received, however, has considerably diminished.

Special Reports.

Several reports describing the general ^A•ork of the Bureau as well

as special investigations where such reports are of a more or less

popular character have been prepared by the section for other Government organizations, technical journals, and the daily press.

The Technical News Bulletin has been issued each month to give

prompt announcement of Bureau researches to industrial experts,

research laboratories, and technical libraries, with a view to securing

prompt use of the Bureau's data in the industries.

Directing Inquiries.

Incoming inquiries by mail and tele])hone are routed to members

of the staff best qualified to answer the questions. In the case of

general inquiries concerning the functions of the Bureau, the answer

is prepared or given directly by this section. Many letters are re- ceived each week from newspaper information bureaus, and the routing of these communications forms part of the work of the section.

PUBLICATIONS.

Distribution.

Last year's report mentioned the requests for effective means of

keeping the public informed of the results of the Bureau's work.

During the past year special attention has been given to the an- nouncement of new publications which is now handled effectively in

several ways : (a) Announcements in the monthly list issued by the

Superintendent of Documents, of which a large edition is circulated ; (b) announcements in the monthly list of Department of Commerce
REPORT or DIRECTOR OE BUREAU OE STANDARDS. 267

publications, of which more than 10,000 copies are distributed to

journals, industrial concerns, and libraries; (c) technical abstracts of

all new publications distributed to the technical press; {d) announcements in the monthly issues of the Bureau's Technical News Bulletin,

and (e) publication of title and abstract in the descriptive list of

the Bureau's publications, Circular 24 and supplements thereto; (/)

an advanced copy of each new publication is sent with a personal

letter to the editor of selected technical journals directly concerned

with the subjects treated; and {g) in addition to the above copies of

Bureau publications are sent by the Superintendent of Documents

by provision of law to selected libraries throughout the country

known as " Government depository libraries," which undertake to

keep the publications available for consultation by the public.

Publications Issued During the Year.

During the fiscal year just closed the Bureau has issued 86 new

publications, a supplement to the Bureau's list of publications, and

24 reprints, 110 publications in all. The 86 new publications comprise 33 scientific papers, giving the results of scientific researches;

27 technologic papers, giving results of new investigations in the

field of engineering and general technology; 18 circulars, containing

important compiled technical information in the Bureau's field and

useful to the industries, and especially to scientific and technical

laboratories; 3 handbooks and 5 miscellaneous publications. The

new series of handbooks has been added during the fiscal year and

comprised the weights and measures manual, two safety codes, and

similar regulations prepared by the Bureau.

The following publications were issued during the year

SCIENTIFIC PAPEES.

Spectrophotoelectric sensitivity of thalofide.

An electron-tube transmitter of completely modulated waves.

Testing of magnetic compasses.

Measurement of hysteresis values from high magnetizing forces. Variation of res'dual induction and coercive force with magnetizing force. A new microphotometer for photographic densities.

Atomic theory and low-voltage arcs in caesium vapor.

Permeability of rubber to gases. Adjustment of parabolic and linear curves to observations taken at equal in- tervals of independent variable.

Relative spectral transmission of the atmosphere.

The two common failures of the Clark standard cell. Measurement of diffuse reflection factors and a new absolute reflectometer

(with bibliography).

A photographic method of detecting changes in a complicated group of objects.

Measurements on the thermal dilatation of glass at high temperatures.

Air forces on circular cylinders, axes normal to the wind, with special reference

to dynamical similarity.

Relation of the hfgh-tem-perature treatment of high-speed steel to secondary

hardening and red-hardness.

Thermal and physical changes accompanying the heating of hardened carbon

steels. A study of the relation between the Brinell hardness and the grain size of

annealed carbon steels. Positive and negative photoelectrical properties of molybdenite and several

other substances.

Metallographic etching reagents : I, for copper. Ionization and resonance potentials of some nonmetallic elements.
268 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Infra-red tx-ausuiission and refraction data on standard lens and prism material

(with bibliography).

Use of ammonium persulphate for revealing the macrostructure of iron and

steel. Resonance potentials and low-voltage arcs for metals of the second group of the

periodic table. Magnetic reluctivity relationship as related to certain structures of a eutectoidcarbon steel. A simple portable instrument for the absolute measurement of reflection and

transmission factors. Present status of the constants and verification of the laws of thermal radiation of a uniformly heated inclosure (with bibliography).

Recent modifications in the construction of platinum resistance thermometers.

Effect of the rate of cooling on the magnetic and other properties of an annealed

eutectoid-carbon steel. A new method for the measurement of photographic filter factors.

Thermal expansion of copper and some of its important industrial alloys.

Wave-length measurements in arc spectra photographed in the yellow, red, and

infra-red.

Spectrophotoelectrical sensitivity of proustite.

TECHNOLOGIC PAPERS.

Saybolt viscosity of blends.

Enamels for sheet iron and steel. Laboratory wearing test to determine the relative wear resistance of sole

leather at different deptJis throughout the thickness of a hide.

An examination of the Munsell color system : I, Spectral and total reflection and

the Munsell scale of value.

Color and spectral composition of certain high-intensity searchlight arcs. Measurement of plasticity of mortars and plasters.

Pyrometric practice.

Automatic apparatus for intermittent testing.

Cast iron for locomotive-cylinder parts.

Tests of bond resistance between concrete and steel. Effects of Cal as an accelerator of the hardening of Portland cement mixtures.

Pouring and pressure tests of concrete. Slushing oils. Sulphur in petroleum oils. Steel rails from sink-head and ordinary rail ingots.

Electric-arc welding of steel: I, Properties of the ai-c-fused metal (with bibliography).

Causes and prevention of the formation of noncondensible gases in ammonia

absorption refrigeration machines.

Colored wall plaster.

^Effect of repeated reversals of stress on double-reinforced concrete beams.

Notes on small flow meters for air, especially orifice meters. Fire tests of building columns.

Experiments on copper crusher cylinders.

Oscillograph measurements of the instantaneous values of current and voltage

in the batteiT circuit of automobiles.

A study of test methods for the purpose of developing standard specifications

for paper bags for cement and lime.

Some properties of white metal bearing alloys at elevated temperatures.

Method for differentiating and estimating unbleached sulphite and sulphate

pulps in paper.

" Black nickel " plating solutions.

CIBCUI.ABS.

Operation and care of vehicle-type batteries (with glossary).

Inks: Their composition, manufacture, and methods of testing.

Recommended specifications for green paint, semipaste and ready-mixed.

Recommended specifications for volatile mineral spirits for thinning paints.

Carbonization of lubricating oils. Nickel (with bibliography).
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 269

Physical properties of materials: I, Streugtlis and related properties of metals

and certain other engineering materials.

Recommended specification for composite thinner for tliinning semipaste paints

when the use of straight linseed oil is not justified.

Recommended specification for spar varnish.

Recommended specification for asphalt varnish.

Recommended specification for liquid paint dryer.

Lime: Definitions and specifications.

The testing of paper.

Gypsum : Properties, definitions, and uses. Sand-lime bricli : Description and specification.

Specifications for marine sextants. Recommended specification for flat interior lithophone paint, wliite and light

tints. HANBBOOKS.

National safety code for protection of the heads and eyes of industrial workers.

National electrical safety code.

Discussion of the national electrical safety code.

MISCELLANEOUS PXIBLICATIONS.

Progress report of National Screw Thread Commission.

Weights and measures : Thirteenth annual conference of representatives from

various States held at Bureau, Washington, D. C, May 24^-27, 1920.

Annual report of Director, 1920.

Buying commodities by weight or measure (extracts adapted from Bureau

Circular 55, Measurements for the household).

War work of Bureau.
IV. ENGINEERING AND CONSTRUCTION.

This division is concerned with the operation and maintenance of the power plant, 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. There

were practically no additions of any importance to the mechanical

plant equipment during the past year. One soot blower was installed

on No. 5 boiler, and boilers Nos. 3, 4, and 5 were equipped with feedwater regulators. The work of greatest moment to this section during the year was the installation of a duplicate feeder for emergency

service which has recently been completed. Interruptions in the

service, which in the beginning of the fiscal year were very frequent,

have steadily declined. It is hoped that the emergency feeder will

provide for practically continuous service. The frequency' changer

for securing 3-phase 60-cycle power has become seriously overloaded.

Steps are being taken toward securing a larger unit of similar design.

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 performed by this sec- tion. Work was continued upon equipping the laboratories in the

industrial building and the installations of permanent wiring in the

dynamometer laboratory. The paper mill and laboratory and the

cotton mill in the industrial building were fully equipped. Numerous

small jobs widely distributed but less extensive were also completed.

Owing to the smaller demand for new electric construction work a

great deal of progress was made on overhauling plant equipment. A

cable system is being designed for signals, watchman's electrical clock

stations, etc., which it is hoped may be installed in the near future.

Plumbing and Pipe Fitting.

This section is concerned with the installation, maintenance, and

repair of all pipe work required for the distribution and use of water,

steam, gas, air, vacuum, and refrigeration services, as well as piping

required in connection with the power-plant equipment. During the

past year larger jobs of new construction included the installation

of about 40 emergency safety showers in the chemical laboratory, the

complete equipment of cooling chambers and other piping in the

aeronautic instruments laboratory, additional radiators for adequate

heating of the west side of the west building, and an auxiliary steam

270
REPORT or DIRECTOR OF BUREAU OF STANDARDS. 271

main for the chemical laboratory, which main will amply provide for

the summer requirements of that building. Numerous small construction jobs were completed and a great deal of progress was made

on plant maintenance and repair work.

BUILDINGS AND GROUNDS.

Grounds.

Some progress has been made in the improvement of the appearance of the grounds. Grading was carried out south and east of the

industrial building, east of the chemistry laboratory, and west of

the northwest building.

I
V. GENERAL RECOMMENDATIONS.

Salaries.

I must again call attention to a serious condition which has been

mentioned in the last three reports of this Bureau, but unfortunately

without effect, namel3^ the great disparity between the salaries paid

scientific and technical experts in the Government service and men

engaged in similar work for industrial concerns and educational institutions. This is a real menace to the research work of the Government, which in time will be felt by every industry and individual

throughout the country.

While, as mentioned in the introductory chapter of this report,

the Bureau can offer a reasonably good entrance salary to young

men just out of college, it can not compete on anything like equal

terms with outside organizations when the more responsible positions are considered. The men in these positions are among the most

valuable in the Government's employ, and many have voluntarily

remained in the service from a sense of patriotic duty and at large

financial sacrifices. On the other hand, a large number have been

forced to accept positions with private corporations, schools, and

colleges, although in doing so they realize that the opportunities for

research will be far less than in a National institution.

There should be no need for such sacrifices as those just mentioned.

The Government can afford to pay and should pay its experts a salary on a plane with that which they can earn in private, employment. This matter is particularly serious in the case of the Bureau

of Standards, as its sole product is scientific information, which is

dependent entirely upon scientific research of the highest grade.

Many of the investigations necessarily cover long periods, and the

loss of the expert in charge may be equivalent to setting back the

whole investigation for a year. It is earnestly recommended that

steps be taken immediately to remedy this situation, the seriousness

of which is becoming greater each year.

Power Plant.

As pointed out in the reports for 1919 and 1920, the power plant

of the Bureau of Standards has for several years been inadequate to

meet the demands made upon it. The original plant was well

adapted to take care of the requirements of the Bureau at the time

it was built, but the institution has now completely outgrown the

equipment. It has been necessary to install two additional boiler

]3lants to furnish sufficient steam for heating purposes, and the

greater part of the electrical service for power and light is now

bought from the local power company. Such decentralization is

wasteful and unsatisfactory. It is a well-known fact that a number

of small units are far less economical than a larger central plant.

(Commercial electric power is poorly adapted to supply exacting

laboi'atory requirements. Interruptions to such service can not be

avoided, and such cessations of the power supply may mean the loss

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KEPOBT OF DIRECTOR OF BUREAU OF STANDARDS. 273

of valuable experimental data through the shutting down of laboratory equipment.

A modern central power plant capable of supplying all the necessities of the Bureau in the way of heat, light, power, refrigeration,

compressed air, and vacuum services should be constructed as soon as

possible. The first cost of such a plant would be saved in a short

time through greater economy in power production and more satisfactory service.

Care of Buildings.

The number of janitors, laborers, and watchmen necessary to

properly care for the buildings and grounds is still entirely inadequate. As stated in the previous report, laboratories require con- siderably more janitor and watchman service than ordinary buildings. The nature of the work is such that it requires constant care

to keep the buildings in order. Many experiments require continu- ous operation of some sort, and in buildings where such work is in

progress Avatchmen must be constantly on the alert. The watchmen

must use intelligence in case of accident and give attention to con- tinuous operations. To curtail necessary services of this character

is questionable economy, and it is a well-known fact that lack of such

service has resulted in accidents, thefts, and poor upkeep of buildings.

Buildings and Grounds.

It is recommended that provision be made by Congress for the

purchase of the land between the present boundary of the Bureau's

property and Connecticut Avenue on the east. This tract is needed

to round out the site, and as it will without doubt be purchased

eventually it would be better to secure it now before it is built upon.

Although some progress has been made during the year in grading and clearing up the grounds and in the construction of short

stretches of permanent road a more adequate fund should be provided for this purpose.

Respectfully,

S. W. Stratton,

DirecU

To Hon. Herbert Hoover,

Secretary of Commerce.

64984—21 18

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II