ANNUAL REPORT

OF THE

DIRECTOR

BUREAU OF STANDARDS

TO THE

SECRETARY OF COMMERCE

FOR THE

FISCAL YEAR ENDED JUNE 30, 1917

WASHINGTON

GOVERNMENT PRINTING OFFICE

1917
9
ANNUAL REPORT

OF THE

DIRECTOR

BUREAU OF STANDARDS

TO THE

SECRETARY OF COMMERCE

FOR THE

FISCAL YEAR ENDED JUNE 30, 1917

WASHINGTON

GOVERNMENT PRINTING OFFICE

1917

CONTENTS.

PageChart showing functions of Bureau facing. . 11

I. F\mctions, organization, and location 11

1. Standards of measurement 11

2. Physical constants 12

3. Standards of quality 12

4. Standards of performance 13

5. Standards of practice 14

6. Relation of the Bureau's work to the public 14

7. Relation of the Bureau's work to the Government service 1&

8. Organization 17

9. Location 1&

II. Scientific and technical divisions., 19-

1. Weights and measures 19 Length measures 19

Linear expansion of materials 19 Standard screen scale 20

Gauge work 20

Optical protractor 21

Leather measuring machines 21

Capacity measures 22

Volumetric glassware and hydrometers 22

Haemacytometers 22

Liquid-measuring pumps 22

Gas-measuring instruments 23

Weights and balances 23

New type of balance 24

Testing scales by use of water • 24

Track-scale work 24

Location, condition, and ownership of track scales tested 25

Reports on track scales tested 25

Technical information regarding track scales 26

Building for housing master scale 27

Density determinations of materials 27

New sugar tables 27

Barometry, and aeronautic instruments 27

Watch testing 28

Lime-barrel act 28

Rules and regulations for barrel laws 28

Uniformity in inspection of weights and measures 29

Anniial Conference on Weights and Measures 30

Cooperation with State stiia with local officials 30

Information furnished on weights and measures subjects 31

2. Heat and thermometry 31

New regulations governing tests of clinical thermometers 31

Standard temperature scale 32

Copper-constantan thermocouples 32

Depression of the ice point of thermometers 32

Standard boiling points 33- Standard heat samples for use in calorimetry 33

Standard samples for thermometric fixed points 33- High-temperature investigations 33

Low-temperatiue laboratory 34

Mercury vapor pump 35

Refrigeration constants. . 35

Calorimeter for the' determination of latent and specific heats

of fluids 35

3
4 ' CONTENTS.

II. Scientific and technical divisions—Continued.

2. Heat and thermometry—Continued. Page. Specific heat of liquid ammonia 36

Latent heat of vaporization of ammonia 36

Latent heat of pressure variation of liquid ammonia 37

Specific volumes of ammonia in the liquid and vapor phases . . 38

Comj)ressibility of liquid ammonia 38

Density-temperature-concentration relations of aqua ammonia 38

Pressure-temperature relation for vapor in equilibrium with

aqua ammonia 38

Temperature-concentration relation for vapor in equilibrium

with aqua ammonia 39

Specific heats of sodium chloride brines 39

Chemical investig'ations relating to refrigeration constants... 40

Thermal conductivities of insulating and structural materials . . 40

Fire-resisting properties of structural materials 40

Fire tests of building columns 40

Fire tests of reinforced concrete columns 42

Thermal efficiencies of column coverings 42

Strength of steel at high temperatures 43

Panel-testing furnace 43

Building codes, information, cooperative work, etc 43

Activities in technical societies, etc 44

Information furnished, reports, etc 44

Heat and thermometric apparatus tests 45

3. Electricity 45

Scope of the electrical work 45

Relation of the electrical work to the military services 46

Silver voltameter ' 47

Standard cell work •. . 47 Investigation of inductance coils 47 Study of the electromagnet mo\ing-coil galvanometer 47 A. C.-D. C. comparator 48

Bridge for testing precision resistance standards 48

Electrically operated titning fork for time measurements 48

Instrument transformers - 49

New method of testing current transformers' 49

Remote control system for motor generators 49

Electrolytic cleaning of silver 49

Electrical properties of silver sulphide 50

Methods of testing transformer oils 50

Radio service to the Government 50

Fog signalling 50

Radio direction finder 51

Radio instruments and measurements 51

Radio testing 51

Magnetic uniformity of straight bars 51 Development of a new permeameter 52

Calibration of bismuth spiralis 52

Study of the magnetic susceptibility of feebly magnetic substances 52

Magnetic analysis 52

Magnetic compass investigation 54

Increase in the Bureau's stock of radium 54

Radium emanation 54

Radium luminous preparations 54

Radium testing 55 X-ray testing 55 Improved methods of measurement in photometry 55

Life testing of gas-filled lamps 56

Investigation on flames and gas-mantle lamps 56 Tests of miscellaneous illuminants 57 Inspection and life-test of lamps for the Government 57

Electrical testing 58

Information furnished on electrical subjects 58

New fee circular 59
CONTENTS. 5

II. Scientific and technical divisions—Continued.

3. Electricity—Continued. Page.

Publications on electric units and standards 59- Public utility investigations 60

Gas service rules 60

Standards for gas ser^dce as affected by war-time conditions. . 61

Gas laboratory methods 61

Relation between heating value of gas and its usefulness 62

Inspections of gas mantle lighting 62

Proposed national gas safety code 63

Economic importance of the national gas safety code 63

Electrical service rules 64

Street-lighting service 65

National electrical safety code 65

National electrical safety code in practical use. 66

Scope and application of the electrical safety code 67

Inspections under the electrical safety code 67

Organizations cooperating in the preparation and revision of electrical safety code 6&

Electrical protection for householders 68

Special problems in overhead lines and industrial installations 68

Electrolysis problem among public utilities J 69

Economic importance of the electrolysis problem 69

Inconvenience and hazard due to electrolysis 70

Methods of mitigation of electrolysis 71

Recent electrolysis work of the Bureau 71 Leakage of current from electric railways 72

Advice to municipalities and corporations 72

Lightning protection 72

Investigations on grounding of secondary electrical circuits. . . 72

Experimental study of telephone apparatus 73

Telephone service standards 74

Submarine telegraphy 74

Relation of the Bureau to municipalities and public-service

commissions 75

Necessity for increasing the public-utility work of the Bureau. 75

4. Light and optical instruments 77 Determination of standard wave lengths 77

Infra-red photography 77 Refractive index and dispersion of air 79

Spectroscopic analysis 79

Rare gas discharge tubes 80

Solubilities in the sugar group 80

Influences of temperature on the speed of inversion of sugar. . 81

Specifications for commercial grades of sugar 81

Basis of saccharimeter standardization 81

(constants of the quartz-wedge saccharimeter 82

Rotation of quartz at high temperatures 82

Magnetic rotation by magnetic substances 82

Bureau of Standards Baume scale 83

Standard glassware for customs laboratories 84

Circular on polarimetry 84

Polarimetric tests of raw sugars 84

Sampling molasses in tank cars 84

Polarimetric tests of molasses 85

Information furnished on polarimetry 85

Polarimetric testing 85

Standard samples 85

Installation of sugar laboratory at Savannah, Ga 85

Supervision of the customs laboratories of the Treasury Department 85

Color standards investigation 86

Testing, extension, and improvement of spectrophotometric

methods 86

Fundamental data needed for reference in colorimetry 87

Establishment of working standards of color 88

Design and construction of colorimetric apparatus 89
6 CONTENTS.

II. Scientific and technical divisions—Continued.

4. Light and optical instruments—Continued. Page. Information furnished on color and color specifications 90

Tests of color, spectral transmission and transparency 90

Turbidimetry 90

Interference methods for measuring thermal expansion 91

Investigation of the performance of American-made photographic and projection lenses 91

Telephoto lenses and distance photography 91

Development of optical systems 92

Testing of optical systems 92

Refractive indices 92

Information furnished on optical systems and optical glass .... 92

Optical constants of chemical glassware 93

Radiometry 93 Constants of radiation of a uniformly heated inclosure 93

Visibility of radiation of the average eye 94

Mechanical equivalent of light 94

Emissive properties of tungsten 94

Glasses for protecting the eyes from injurious radiations 94

Photoelectric properties of various substances 95

Information furnished on radiometric subjects 95

Publications on radiometry 95

5. Chemistry 95

Rapid electrolytic determination of carbon in steel 95

Nitrogen in steel 96

The Goeren's method for determining the gas content of steels . 96

Determination of gases in steel by the Goutal method 96

Determination of oxygen in steel 96

Oxygen content of steels deoxidizable in various ways 96

Ladle ingot test investigation 96

Preparation of iron-carbon alloys 97

Platimnn investigation 97

Variation of commercial gases from Boyle's law 97

Specific gravity of gases 97

Preparation and properties of hydrogen 98

Balloon gas investigation 98

Combustion gas detectors 98

Chemical work on balloon fabrics 99

Chemical work on refrigeration problems 99

Chemical work on the standard cell 99

Electrotyping and electroplating investigation 100

Renewal of work on various analytical problems 100

Paint and varnish investigations 101

Nonferrous alloys and coated materials 101

Bituminous materials 102

Chemical work on cement 102

Chemical tests of lubricants 103

Chemical work on leather 103

Chemical analysis of rubber 103

Chemical work on paper 103 Tests of chemical glassware and porcelain 103

Standard analyzed samples 104

Chemical testing 104

Miscellaneous chemical tests and investigations 104

Chemical publications 104

New chemistry building 105

•0. Engineering research and testing 105 Water-current meter rating stations 105

Different forms of cable suspension for current meters 106

Depth of submersion of current meters 106

Fire extinguisher investigations and tests 107

Fire extinguishing equipment for wooden submarine chasers. . 107

Radiator traps used in vacuum heating systems 107 High-pressure gauges 108 Sounding tubes 108

Spirits meter , 108
CONTENTS. 7,

II. Scientific and technical divisions—Continued.

6. Engineering research and testing—Continued. Page. Patrol lanterns for the United States Coast Guard service 108

Gasoline intensifiers for automobile engines 108

Miscellaneous tests of instruments and devices 108

Cooperation with scientific and technical societies 109

Investigations relating to mechanical appliances 109

Spark-plug investigations 109

Aeronautic radiator investigations 109

Installation of aeronautic engine testing laboratories 110

Testing of aeronautic engines under conditions of reduced at- mospheric pressure 110

Liberty engine Ill

7. Metallurgy Ill

Railway materials investigation Ill

Chilled car-wheel investigation Ill

Iron-carbon system 112

Second ingot investigation 112

Ladle test ingot metallurgical investigation 112

Gases and oxides in steel 112

Gun erosion and allied' phenomena 113

Temperature measurements in metallurgical practice 113

Thermocouple nichrome-constantan 113

Failure of brasses and bronzes 113

Corrosion of brasses and bronzes 114

Impurities in cast bronze and brass 114

Properties of commercial cast brasses and bronzes 114

Foundry sands 114

Deterioration of tinned copper roofing 115

Properties of electrolytically deposited copper 115

Protective metallic coatings on metals 115

Fusible boiler plugs 115

Melting points of refractory elements 115

Cooperation with military Government departments 115

Cooperative work in metals 116

Activity in technical or scientific societies 116

Metallurgical tests 117

Information furnished to the Government and the public Il7

Circulars of information on metallurgical subjects ll7

Metallurgical publications 118

8. Structural, engineering, and miscellaneous materials 118

Investigation of structural steel columns 118

Physical investigations of railway material 119

Investigation of the physical properties of zinc 120

Investigation of methods of calibration of testing machines. . . 120

Investigation of the effect of kiln-drying spruce 120

Airplane strut investigation 121

Resistance of wood to alternating stress 121

Study of strains in car wheels 121

Machine-tool investigations 121

Strength of galvanized wire 122

Strength of latticed aluminum columns 122

Failure of bridge material 122

Strength of bridge material 122

Failure of hull material 123

Investigation of material from experimental bulkheads 123

Investigation of wire rope 123

Strength of brick piers 123

Investigation of the physical properties of earths 124

Information furnished regarding strength of metals and alloys. 125

Tests of a semi-investigative nature 125

Investigation and testing of materials for the Signal Corps. ... 126

Tests on the strength of materials 126

Investigation and testing of cement, concrete, and stone 127

Standard specifications for Portland cement 127

Foreign specifications for Portland cement. . 127

Effect of fine grinding of Portland cement 127

Minor constituents of Portland cement 128
II. Scientific and teclinical divisions—-Continued.

8. Structural, ens:ineering, and miscellaneous materials—Contd. Page.

Constitution of Portland cement 128

Granulometric air analyzer 128

Air separator for cement 128

' Standard cement sieves 129

Standard fineness sample 129

Hydraulic cements other than Portland cement 129

' Durability of concrete in sea water 130

Durability of concrete in alkali waters 130

Investigation of integral waterproofing compounds 131

Development of an accelerator for hardening concrete 131

Cast-iron reinforced concrete columns 132

Floor construction tests 132

Investigation of composition flooring 132

Value of various materials as concrete aggregate 133

Effect of moisture and temperature changes on concrete 133

Tests of field-made concrete for Lincoln Memorial 133

Investigation of building stones of the United States 133

Stucco and plaster investigation 134

Information furnished concerning cement and concrete 135

Publications on cement and concrete 136

Routine cement inspection and testing of cement and concrete. 136

Miscellaneous tests of stone, sand, gravel, etc 137

Sand-lime brick 137

Hydrated lime in concrete 137

Measuring of plasticity and sand-carrying capacity of lime 138

Properties of hydrated limes 138

Decomposition of calcium and magnesium hydroxides 138

Investigation of gypsum 138

Architectural terra cotta 139

Investigation of tile and tile walls 139' Silica-brick investigation 139

Study of American clay refractories 140

Special refractories for high furnace temperatures 140

Study of ceramic kilns 140

American plastic bond clays 140

Sizing of calcined clay 141

Clay tests 141

Porcelain investigations 141

Porcelain for spark plugs 141

Enameled-iron investigations 142

Optical-glass investigation 142

Investigation of lubricating oils 142

Information furnished regarding lubricating oils 142

Investigation of leather 143

Investigation of shark and other fish-skin leather 143

Experimental rubber plant 143

Investigation of solid-rubber tires for motor trucks 144

Rubber eye shades for the range finders of battleships 144

Cooperation with technical societies, manufacturers, and con- sumers 144

Assistance rendered Government departments 144

Information furnished on physical tests of rubber and leather . . 145

Special tests of miscellaneous materials 145

Tests of miscellaneous materials 146

Comparison of cotton and wool flags 146

Identification of textile fibers 146

Sewing-machine stitches 146

Tensile strength of fabrics 146

Textile conference 147

Information furnished regarding textiles and textile testing. . 147

Testing of textiles 147

Buttermilk casein as a paper-sizing material 147

Domestic clays in the paper industry 148

Paper-testing devices 148

Utilization of waste paper for remanufacture into paper 148

Paper bags for shipping cement, lime, and gypsum 148
CONTENTS. 9

II. Scientific and technidal divisions—Continued.

8. Structural, engineering, and miscellaneous materials—Contd. Page. Manufacture of filter paper 149

Information furnished concerning paper 149

Paper testing 150

III. Office 151

Publications 151

Technical library 152

Personnel 152

Appropriations statements 152

Summary of tests 154

Metric system 154

Exhibits of the activities of the Bureau 155 IV. Recommendations 156 Increase in scientific staff 156 Increase in salaries 156

Additions in the clerical, operating, and construction staffs 156

Increases in special funds 156

Buildings 158

New refrigerating machine 158

1

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• - ' .

Sc. or
NATIONAL BUREAU OF STANDARDS

Washington, D. C.

1917

FUNCTIONS

Development, construction, custody, and maintenance

of reference and working

STANDARDS

and their intercomparison, improvement, and application

in science, engineering, industry, and commerce.

18532°—17. {To face page 11.

)
REPORT

OF THE

DIRECTOR, BUREAU OF STANDARDS.

Department of Commerce,

Bureau of Standards,

Washington, July 1, 1917.

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

Bureau of Standards for the fiscal year ended June 30, 1917.

I. FUNCTIONS, ORGANIZATION, AND LOCATION.

Before describing in detail the various scientific and technical

problems in which the Bureau of Standards is engaged, the following

brief statement as to its functions and organization may be helpful

to those unfamiliar with the subject of standardization in the 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.

1. STANDARDS OF MEASUREMENT.

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

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

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

and working standards prepared of these parts, and for the measure- ment of greater lengths standards must be prepared which are multiples of the fundamental standard. This process of subdividing and

multiplying the standard involves difficulties as great as those met

with in the preparation of the fundamental standard itself.

The construction of a set of standard weights from a single unit is also an illustration; a whole set of standard weights must be prepared before the standard weight of the Government can become

available to the public. When the standard of length or weight has

be§n found with as many desirable qualities as possible, and before

the working standards of the subdivisions or multiples can be prepared, the question as to the method of comparison arises, which

again involves the solution of difficult scientific problems in connection Avith the balance or the methods used. These balances range

from that capable of measuring the thousandth part of a milligram

11
NATIONAL BUREAU OF STANDARDS

WashlnKton, D. C. 1917

(•UNCTIONS

Development, construction, custody, and maintenance

of reference and working

STANDARDS

and their intercomparison, improvement, and application

In science, engineering, industry, and commerce.

STANDARDS

STANDARDS OF MEASUREMENT

Reference and working standards for measurements of all kinds, including fundamental and derived STANDARDS OP MEASUREMENT for expressing the quantitative aspects of space, time, matter, energy, motion, and of

their interrelations. Bf dcfioItloD, fpeclficailon. or material itandard, coveriot, for example, length, area, and volume; ra»»9, wcishl. dtnkily. and preisurc; heat, light, electricity, and radioactivity, Includlnc quantity, flux. Intenilty, density, etc.

STANDARD CONSTANTS

Natural standards or the measured ntmicrical 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; vitcosltiei; melting and boiling points; heat capacity; heats of combustion; velocity

of propagation of Hcht; conductivities of materials to heat and light; electrochemical and atomic weights and many similar magnitudes determined experimentally with ouxl* mum 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 m.Knituilc of each consliluent property perttneot to the quality involved, and specific magnitude in unite of meaeure of luch algnlficant factor, aa uniformity, compoaltion, fortD. atnictur., and oth.ra.

PURPOSE

To aid ACCURACY IN INDUSTRY through uniform uid correct meuumTo ASSIST COMMERCE IN SIZE STANDARDIZATION of container, and

products; To PROMOTE JUSTICE IN DAILY TRADE through systematic in.pec- tion 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, e«p«riment, compu

tation, and design; To FURNISH an EFFICIENT CONTROL for industrial processes in secur- ing reproducible and uniformly high quality in output

To SECURE UNIFORMITY OF PRACTICE in graduating measuring

instruments, compiling tables, in standards of quality and performance. and wherever uniformity is desirable; To AID LABORATORY RESEARCH BY REDUCING ERRORS and un- certainty 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 diapuiei 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 Induilry by affording quality standards by which materials may be made, sold, and

tested.

4

STANDARDS OF PERFORMANCE

Specification of operative efSciency 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. durabiUtx, and Other factor, which together define the net efficiency of an appllanc, or machloo.

5

STANDARDS OF PRACTICE

Codes and regulations impartially analyzed and formulated after study and

experiment into STANDARDS OF PRACTICE for technical regulation of

construction, installation, operation, and based upon standards of measurement, quality, and performance.

Collation of standard data, numerical magnitudes, and imngw of tb. pertinent factors dafiaiaf

quality, safety, economy, convenience, and .Acicncy.

I

To CLARIFY THE UNDERSTANDING between maker, seUer, buyer, and

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

To FURNISH for each utiUty a single IMPERSONAL STANDARD of practice as a BASIS FOR AGREEMENT of all interests clearly dcfintd in measurable terms; To INSURE EFFECTIVE DESIGN and INSTALLATION of uUlitles of

all kinds

To PROMOTE SAFETY and CONVENIENCE in the maintenance and OPERATION of such utilities; To SECURE UNIFORMITY OF PRACTICE where such Is practicable, and EFFECTIVE ALTERNATES in other cases.

12 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

to the large testing machine capable of measuring a load of thousands of tons. The complete range must be covered, which involves

not onl}^ 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 througliout the

country, and thej'^ 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 ever}^ scientific investigation, industrial process, engineering

structure, or commercial transaction.

2. PHYSICAL CONSTANTS.

There are many fixed relations between physical quantities, the

values of which it is extremely important to know. These values

are usually termed physical constants," and are iised in every branch

of scientific work or industry. The amount of lieat required- to

change a pound of water into steam under normal conditions and the

relation betAveen heat and mechanical energy are two impoi^tant 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 re.qiiired 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 important commercial transactions concerned in electricity.

Accurate and authoritative values of these constants are just as

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

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

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

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

those not engaged in the scientific or technical work where these

constants are used.

3. 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 b}' means of the usual standards

of measurement. A certain kind of steel, a cement, a paint, an oil, or a paper or cloth is found by use to be good or poor. The questions

then arise. Why is it good or poor ; What are the physical or chemical properties or the particular combination of elements which make
KEPORT OF DIRECTOR OF BUREAU OF STANDARDS. 13

it of good or poor quality ; Hoav are its properties to be measured or

its constituents determined ? These are questions for the laboratory

to ansAver and inv olve 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 max result precisely in the same thing ; that

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

the Bureau's investigations in connection with the properties of materials are to enable the user of these materials, first, to select intelli-

^•ently the material best suited for the purj^ose; second, to specify

it in terms Avhich 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 busi- ness 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 Avhich information, as stated above, is se- cured in connection with the testing of materials purchased by the

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

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

where proper standards of quality and methods of measurement have

I'.een developed. It must not be assumed that the piirchaser or user

is the part}' principall_v benefited in the development of such standards; on the contrary, the manufacturer, first of all, is interested in

the quality of all things Avhich alfect the quality of his product, and

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

pointing out and measurement of those properties upon Avhich the

quality of the materials depends, it is to be regretted that its force

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

process upon Avhich the quality of the output depends.

4. STANDARDS OF PERFORMANCE.

The value of an instrument, dcA'ice, 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

Avliich are correct and susceptible of measurement. As in the case
14 REPORT OF DIEECTOR OF BUREAU OF STANDARDS.

of standards of quality, the standard involved is more often in

the form of a specification, but specifications are useless unless based

upon correct scientific and mechanical principles and supplemented

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

or not the specifications or guaranties have been complied with.

The performance of an engine or boiler, a pump, an electrical generator or motor, a weighing device, or a telescope can usually be

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

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

do this properly involves the use of standards of measurement,

standard values of constants, and standards of quality. The Bureau

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

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

which to base specifications and only to the more important classes

of apparatus. To secure this information involves investigations

quite as scientific in character and as difficult as in the case of other

standards, as well as a knowledge of technical and manufacturing

processes.

The Bureau's activities in this field have only been developed to

a slight extent and almost entirely in connection Avith Government

purchases. It has had in this, as well as in the field of the properties of materials, the most heartv cooiDeration of the various Government experts, manufacturers, engineers, and technical societies.

S. STANDARDS OF PRACTICE.

Standards of practice are generally involved in the enactment of

laws when technical and scientific matters are concerned, in the ordi- nances relating to the regulation of public utilities, and in the establishment of building and safety cedes. Like standards of performance, the}' 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 touch only upon the more important aspects

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

not be covered efficientlj' in private laboratories.

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

It is perfectl}^ obvious, even to om' unfamiliar with the subject,

that the maintenance on the part of the GoA-ernment of correct

standards of measurement or quality or performance calls for con- tinuous 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 seri- ous problem of making the results available and useful to the public.

The Bureau compares with its own standards of measurement the

standards or measuring instruments of States, cities, scientific laboratories, educational institutions, manufacturers, Government bureaus, or the public, for which a nominal fee is charged, except in

the case of the National and State Government institutions. It

gives advice concerning these standards or their use, whether it be

in connection with the e.nactineijt of laws. regu!'>t;ons, or ordinances

concerning the v\Tights and measures of everyday trade or in con-
KEPOET OF DIRECTOR OF BUREAU OF STANDARDS. 15.

nection with precision standards used in scientific work and the industries. It gives advice upon request to State and city officials,

public-service commissions, and public-utility corporations regarding the standards of measurement, or quality, or performance involved in legislation or regulation pertaining to the public utilities.

Many questions of disagreement between the public and utility companies as to these matters are referred to the Bureau for advice or adjustment, often avoiding unfair or inconsistent regulations, as well as long-drawn-out and expensive litigation. 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.

It must not be inferred from the above that the Bureau's activities are devoted principally to the interests of the user or consumer. The fundamental facts regarding standards of measurement, quality, or performance are the very things which most deeply concern manufacturers; they are fundamentally concerned, either directly or indirectly, with the improvement of methods of production or the quality

of the output. It may be said that the Bureau occupies somewhat

the same position with respect to the manufacturing interests of this

country that the bureaus of the Department of Agriculture do to the

agricultural interests. Many industries are just beginning to realize

the importance of precise methods of measurement and scientific

investigation, which, in practically every case, involve some kind of

measurement.

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

finally depend, whether in domestic or forei^ commerce. The use

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

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

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

receives hundreds of letters, as well as many personal visits from

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 measure- ments to the industries has been recognized by all the leading countries of the world. Great Britain maintains the Standards Department of the Board of Trade, which is in charge of the standards and

inspection service of the trade weights and measures; also the National Physical Laboratory, whose functions include matters pertaining to scientific and technical standards, physical constants, and

to some extent the properties of materials. The Laboratoire d'Essais,

of France, w'hile not as extensive as the English institution, is charged

with similar duties. Germany maintains three such institutions—

the Normal-Eichungs Kommission, equipped with the buildings,

personnel, and apparatus necessary in standardizing and controlling

the weights ancl measures of trade; the Physikalisch-Technische

Eeichsanstalt, covering testing and investigations in connection with
16 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

scientific and technical standards other than weights and measures;

and the Prussian Government maintains the Materialpriifungsamt,

a large institution devoted to the investigating and testing of structural, engineering, and other materials.

It is generally recognized that these institutions have been exceedingly important factors in the industrial progress of these countries.

7. RELATION OF THE BUREAU'S WORK TO THE GOVERNMENT

SERVICE.

The bureaus of the Government engaged in scientific and technical

work are necessarily dependent upon standards of measurement of

every variety. In addition, many of them are engaged in the design,

construction, and specification of a great variety of special apparatus, in which the principles of mechanics, heat, optics, electricity, and

chemistry are involved and are vital to their efficiency and successful

operation. In such matters the Bureau has been consulted most

freely by the War and Navy Departments, the Post Office Department, the Department of Agriculture, the Public Health Service, and

others.

The engineering and building construction in progress at all times

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

and safety. The work of testing and investigating the properties of

structural materials was taken up and is carried on primarily for

the purpose of securing the information needed by the Government

service in its structural work. This information is as necessary to

the public in construction work, and every effort is made by the

Bureau to make its findings in a form available to the public generally. The demands for information of this sort have come from

practically all Government bureaus and establishments, but especially

so in connection with the structural work carried on by the Office of

the Supervising Architect, the engineering branches of the Army,

the Bureau of Construction and Eepair of the Navy, the Panama

Canal, and the Reclamation Service.

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

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

performing the service in a manner that is fair to both parties con- cerned in the purchases.
EEPOKT 01" DIRECTOR OF BUREAU OF STANDARDS. 17

Among the many Government bureaus and establishments which

have utilized the Bureau of Standards as a testing institution in

connection with the purchase of supplies may be mentioned the Government Printing Office, in connection with the purchase of paper,

inks, and printing supplies; and the Post Office Department, in

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

range of materials has been tested for the Quartermaster's Department of the Army, the Paymaster's Department 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.

Many bureaus of the Government service are charged with the administration of laAvs and the establishment of regulations in which

scientific data are vital. This is true to a much greater extent than

is generally supposed. The Bureau of Standards has cooperated

freely with such branches of the Government and the service ren- dered 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 such assistance has been given are the

Customs and Internal Revenue Services; the Steamboat-Inspection

and Coast Guard Services, in the promulgation of safety regulations

and the Bureau of Navigation of the Department of Commerce, in

the administration of laws regulating the use and inspection of

ra diotelegraphy

8. ORGANIZATION.

The organization of the Bureau's scientific and technical staff is

based upon the nature of the expert service involved rather than

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

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

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 measure- ments 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 pertaining 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 may be taken up at the Bureau, whether in connection

w^ith the various electrical standards of measurement, electrical constants, the electrical properties of materials, or the performance of

electrical equipment.

18532—17—2
18 REPORT OF DIEECTOB OF BUREAU OF STANDARDS.

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

analj^sis), color measurement, the principles of optical instruments,

and the measurement of the optical properties of materials.

Practically all investigations concerning the various classes of

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

man}^ chemical standards and questions which ai'ise in connection

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

there is a chemical division, cooperating Avith every other division of

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

chemical nature that come to the Bureau and which fall within its

functions.

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

been formed dealing more specifically with large and important

classes of materials, but many of the purely scientific questions involved would be handled by one of the above-mentioned scientific

divisions or jointlj^ 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 research makes investigations and

tests regarding the performance and efficiency of such instruments,,

devices, or machinery as the Bureau may take up that do not fall

directly under one of the scientific divisions. The division is a small one and its work is devoted almost exclusively to assistance given

other departments of the Government and the General Supply Committee in designing, specifying, or testing equipment. It should in

time form one of the more important branches of the Bureau's work.

The questions pertaining to the manufacture, specifications, test- ing, ancl use of the metals and their alloys have become so important

that a division known as the metallurgical division has been formed

of the experts engaged in these problems.

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

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

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

and the care of the buildings and grounds form the engineering and

construction division.

9. LOCATION.

The laboratories of the Bureau of Standards are located in the

northwest section of Washington, on Pierce Mill Eoad, near Connecticut Avenue, and are reached by the Chevy Chase car line. They

were located outside of the business center of Washington in order to

insure freedom from mechanical, electrical, and other disturbances

common to the business and more thickly populated sections of the

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

the employees, especially those engaged in testing and scientific investigation, has been greatly increased by the location of the laboratories

in a section free from the ordinary disturbances of city life.
11. SCIENTIFIC AND TECHNICAL DIVISIONS.

I. WEIGHTS AND MEASURES.

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

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

and the general public]

Length Measures.

About 1.035 articles were measured for length during the year, of

which 781 were polariscope tubes and 156 Avere tapes of steel, invar, or linen. The remainder included 65 gauges and calipers, an increased number over last year, T line standards, 2 level rods, 58 sieves

and sauiples of sieve cloth, and 16 miscellaneous pieces of apparatus.

Linear Expansion of Materials,

During the year there were made 107 expansiv ity tests, 77 of which

were incident to research work carried on by the Bureau; the re- maining tests were made, on specimens submitted b}^ the Federal

Government and from outside sources. In connection with the research work on the linear expansion of

materials, 12 specimens of bronze. 6 of the alpha and 6 of the beta

phase, AT ere thoroughly studied, involving temperature ranges ex- tending from 20° C. to 600° C. This work was carried out as an

investigation of a theory that the differential expansion between

the alpha and beta particles, ordinarily evenly distributed in bronze,

is sufficient to cause the ruptures so commonly met in this class of

material. The results of this study indicate that the difference in. the expansion of the two phases is sufficient to cause these ruptures.

Many interesting details were observed in connection Avith this investigation. Specimens of the alpha phase are regular in their

expansion and after being heated return to their original length,

whereas specimens of the beta phase exhibit peculiarities Avhich are

quite constant and they fail to return to their original length after

being heated to 300° C. or aboA^e.

Research Avork on rolled brass Avas carried out as part of a study

for the determination of the effect of the direction of rolling on the

properties of brass. Twenty-nine samples of varying thickness were

tested, a part of Avhich Avere measured parallel and a part perpendicular to the direction of rolling. The expansion varied somewhat

Avith the thickness of the material and a permanent set resulted after

the samples Avere heated to 300° C, Avhich amounted to as much as

0.4 millimeters per meter for the thin samples. This permanent set

was either an increase or decrease in the length of the specimen

according to whether it had been cut longitudinally or transA^ersely

Avith the direction of rolling.

19
20 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

A preliminary test has been made of six representative specimens

•of 109 samjDles of copper alloy submitted by a lai'ge commercial corn- pan}^ in order to determine the probable behavior of these samples,

ilesearch work is being undertaken in connection with these samples

for the purpose of determining the expansivity properties of the alloy

from which they are made, and the results so far indicate that the

expansivity of this material is a regular function of its composition

in fact, both the first and second terms of a quadratic equation representing the expansion of each alloy vary regularly with the composition.

The unusual behavior of marble imder heat treatment seems to

have received little, if any, consideration by those interested in this

material. A study of marble subjected to heat treatment reveals the

fact that the coefficient of expansion increases from about to 0"^ C.

to 28X10"® at 300° C. Moreover, after the marble has been ex^Danded

hy heat, it does not return to its original dimensions, but a permanent

increase results, the magnitude of which depends upon the temperature to which the specimen has been heated. A permanent increase

in length amounting to as much as 4 millimeters per meter has

resulted from heating a specimen to 300° C. This work has a very

im]3ortant bearing on some of the marble industries, and is especially important in connection with the manufacture of electrical

standards where coils are wound on marble bases.

The results obtained from investigations on nickel steel, begun

during the fiscal year 1916, were checked up and data were found to

be in close agreement, both with the Bureau's previous results and

w'ith those obtained by Guillaume, wherever it was possible to draw

a comparison. This research has been completed and the results are now in course of preparation for publication.

It recently became desirable to make expansion tests to as high as

1,000° C. A new furnace has therefore been designed for this purpose, the special features of which consist of methods of making and

mounting the resistor so that it is readily accessible and easily re- placed in case of an interval break in the electric circuit.

Standard Screen Scale.

The standard screen scale for testing sieves, adopted by a confer- ence of representatives cf various technical societies. Government

bureaus, and private firms interested in sieving tests of materials,

has been issued by the Bureau, together with specifications and toler- ances under which the Bureau will test and certify sieves of this

series. This screen scale has a wide range of openings, from 8 to

0.044 millimeter (0.315 to 0.0017 inch), and is intended to cover practically all materials upon which fineness tests are made. Its adoption Avill unify the results of sieve tests and will reduce the varieties

of sieves required for such work.

Gauge Work.

As soon as it became evident that the Ignited States would be

compelled to expand its military activities, the Bureau profiting by

the experience of the national testing laboratories of Europe, began

to make preparation for the certification of gauges used in the manufacture of munitions. Representatives from the Bureau visited a
BEPOET OP DIRECTOR OP BUREAU OF STANDARDS. 21

number of the munitions plants in the country, and the methods of

gauging employed in these plants were carefully studied. A representative was also sent to Canada for the purpose of studying the

operations of the gauge department of the Ministry of Munitions, a

department organized entii-ely since the beginning of the war. The Bureau then submitted an estimate for an appropriation to

coA'er this work, to be immediately available, and the proposed appropriation w'as made a part of the act making appropriations ta

supply urgent deficiencies in appropriations for the Military ancT- Naval Establishments, which was appi"oved June 15. The BureavE

immediately ordered some of the more important pieces of apparatus that would be required in the work and in the securing of which

the element of time Avas of great importance.

A temj^orary building, constructed some years ago in connection

with experiments on the use of various kinds of cement and lime

coverings for outside walls and -which had never been finished inside, was assigned to the gauge work, and immediate steps were

taken to prepare it for occupancy. This building was almost ready

to occupy by the end of the fiscal year, and a large amount of apparatus and the force needed to carry on this work had been secured.

Optical Protractor.

In preparing for the testing of munition gauges in large quantities, it became necessary for the Bureau to design a number of

special instruments in order to carry on this work. Notable among

these is the optical protractor. This instrument consists of a microscope containing a knife-edge in the ocular plane wdiich can be

txirned about an axis practical llv coincident Avith the optical axis of

the microscope. In use the knife-edge is made coincident with the

other side of the thread and a second reading on the circle taken,,

the difference between the two readings giving the thread angle.

The principal advantage of this protractor over previous designs is

in the increased accuracy with which settings can be made. It is

possible to set the knife-edge parallel Avith the general direction of

the sides of the screw thread being measured within three minutes

of arc under good optical conditions.

Leather Measuring Machines.

At the request of various associations of tanners and shoe manufacturers, the Bureau undertook an iuA^estigation of the machines,

and methods used in the leather trade for the measurement of the

area of hides and skins, the major portion of shoe leather other than

that for soles being purchased on the basis of superficial area. The

area of the skins is generally determined bv passing them through

one special type of measuring machine. The investigation showed',

that the methods hitherto used in the testing of these machines have'

been inadequate. It was found that, in general, the readings of the'

machine were seriously in excess, due partly to over-speeding of

machines, and partly to faults in their design. These errors have

resulted in many cases in serious overcharges, amounting to large

sums of money annually.

A detailed and constructiA-e series of reports Avere prepared, intended to correct faulty methods of test and inspection, and to indi-
22 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

cate points of design requiring special attention. The brief investigation enabled a beginning to be made on the theory and design of

these machines, and it is probable that during the coming year a code of specifications governing their use and test can be issued.

Some information was collected regarding the shrinkage of skins

from the time of tannage, a factor which results in an appreciable

reduction in area, and is therefore important for consideration in

connection with the standardization of methods for leather measurement.

Capacity Measures.

The number of capacity measures submitted for test during the

year was 56. These included standards for State governments, city

governments, and for private firms.

Volumetric Glassware and Hydrometers.

The volumetric apparatus submitted for test during the year consisted of Babcock bottles, burettes, cylindrical graduates, flasks,

measuring pipettes, Giles flasks, specific gravity flasks, and transfer

pipettes. About 1,370 pieces of apparatus were submitted for test. 61 per cent of the total passing the regular tests. There were about

980 hydrometers submitted, of which 683, or 70 per cent, passed the

test. The number of pieces of special apparatus tested was 30.

Blue prints of a set of cone graduates, conforming to the specifications adopted by the Eleventh Annual Conference on Weights and

Measures, were made and sent to various manufacturei^s.

Hsbmacytometers.

Tlie manufacturers of ha?mac_vtometers. instruments fur determining the number of corpuscles in a given quantity of blood, suggested

that the Bureau issue tolerances and specifications for this tyi^e of

apparatus and take up the testing of such instruments regularly.

This suggestion led to an investigation of the accuracy of the various

type^ of hiemacytometers in use. It was foimd in the majority of

cases that the user assumed a greater degree of accuracy for the re- sults obtained than was warranted by the apparatus. In some instances the instrumental inaccuracies Avere of such magnitude as to cause errors in a count of from 25 to 100 per cent. This plainly indicated the necessity for accurately measuring the dijnensions of

hasmacytometer chamliers and for calibrating hsemacytometer pipettes. Tentative tolerances and s]3ecifications have been issued which

are meeting with general apj^roval. Methods have also been devised

for shortening the time required to test this type of apparatus.

Liquid-Measuring Pumps.

The work begun last year on the investigation of liquid-measuring

pumps, with especial reference to the gasoline pum]DS commonly used

for dispensing motor fuel, was continued and extensive tours of inspection and test were made, principally in Illinois and Pennsylvania.

The majority of the pumps tested were found in unsatisfactory condition, and in the aggTegate a very decided and significant tendency

toward a shortage of measurement was indicated. The Bureau has

given considerable aid to weights and measures officials in developing
BEPOBT OF DIRECTOR OF BUREAU ' OF STANDARDS. 23

a routine for the testing of this type of apparatus and in detecting

and correcting the defects developed.

Numerous inquiries were received from manufacturers, weights

and measures officials, and users relating to the design and test of

measuring pumps, and the preparation of the information sought in

many cases required considerable investigation and study.

An extended code of measuring-pump specifications, in tentative

form, has been drawn up and is about ready to be issued.

Gas-Measuring Instruments.

During the past fiscal year a number of laboratory gas meters for

both commercial and experimental work have been calibrated for

State government, city, and industrial laboratories. Some of these

instruments were calibrated at various rates of gas discharge, the re- sults yielding valuable data as to the behavior of this type of apparatus under various conditions.

The investigation of gas-meter testing apparatus, continued from

last year, has been carried on only to a very limited extent, due to

lack of available time. This investigation has included the study

of gas-meter provers and apparatus for testing the same. Ihe improved type of portable cubic-foot apparatus for calibrating meter provers designed and developed by the Bureau and which

was mentioned in the report of last year has been further improved.

A patent, dedicated to the public, has been granted on this apparatus. The cubic-foot apparatus in use in the past was extremely

cumbersome, whereas the new apparatus can be easily carried about

by one man and therefore will be of special value to the State inspector of meter-testing apparatus.

An important part of the work of the Bureau in this connection

has been the instruction of officials of various cities in the methods

of testing different tjpes of laboratory and commercial gas-measuring instruments.

Weights and Balances.

The shortening of the time required for testing ordinary analytical

weights, begun last year, Avas carried out even more successfully than

was expected when the work was first undertaken. The new balance

for weights from 1 to 100 grams, when used under better conditions

than had been tried before, had such constant sensitiveness that aver- age values could be adopted for different loads, and these values

needed to be checked only once or twice during a test. This re- duced the number of readings by from 10 to 30 per cent. It also

became possible to introduce the method of weighing by substitution

in such a way as to reduce still further the number of readings re- quired and at the same time to reduce the amount of handling of the

weights. The computations are also greatly lessened in amount and

much simplified. New forms were developed in which the complete

work of observation and computation appear on the same sheet.

These new forms were tried out in actual practice, perfected, and are now being printed for use in the laboratory. With a satisfactory

balance for the smaller weights it will be possible to reduce the time

required for testing by at least 30 per cent.

The Bureau tolerances for high-grade analytical weights were

adopted by one of the large scientific apparatus houses and also by
24 BEPOBT OF DIEEOTOR OF BUBEAU OF STANDABDS.

a large commission association, through which about 30 of the constituent firms have been supplied with sets of standard weights such

as are needed in their work. The adoption of these tolerances will

enable manufacturers to furnish weights to distributors of scientific

apparatus which will meet the specifications adopted by the Bureau.

Consequently, when such weights are submitted to the Bureau for

test they are more likely to be within the tolerances prescribed than

if no attempt were made by manufacturers to comply with the specifications adopted by the Bureau, and thus a great saving in time is

made in testing the weights.

Preparation is being made to test immediately any Aveights needed

for war purposes which may be submitted by the various departments of the Government or by oiitside firms. To this end every

effort is being made to keep the regular work as nearly up to date

as possible, and extra balances are being overhauled with a view to

using them should occasion arise.

New Type of Balance.

A novel type of balance, characterized by a high sensibility and

yet very simple and inexpensive to manufacture, has been developed

by a member of the staff and described in an article in a leading

engineering periodical. The results of a preliminary test showed

exceedingly good operation, and it appears that this simple and inexpensive balance compares in many respects very favorably with

the more elaborate and costly analytical balances.

Testing Scales by Use of Water.

In compliance with a request for information as to the practicability of testing scales by the use of known volumes of water, determined by filling standard capacity measures, an investigation was

carried out and very promising results were obtained. The object

of using known volumes of water for testing scales is to enable a weights and measures inspector who does not have facilities for

transporting large quantities of standard weights to test scales of

large capacities.

Track-Scale Work.

The railroad trackrsc^le work consists of that carried on at the

Bureau and that done in the field. The work at the Bureau consists of the collection and distribution of information, the preparation of tolerances and specifications on track scales and other weighing devices, the development of the correct theory of scale design

and construction, development of special devices and methods of

tests, investigations of various problems that arise, and a study and

selection of the problems to receive attention. An important feature

of this work has been the interpretation, classification, and arrangement of the data collected in the tests made in the field.

The field equipment in operation during the year consisted of two

test-weight cars of Bureau design, which have been described in

previous reports. The field work comprised the testing of scales by

leans of the equipment provided, making a careful inspection of

36 scales and reporting their condition so that the owners may be

dvised by the Bureau what repairs or changes are necessary to
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 25

put the scales in proper condition. In addition to the testing of

railroad-track scales and master scales, other scales of large capacity

are tested when occasion arises. Additional field equipment has been

purchased by the Bureau, but owing to Avar conditions it has not yet

been delivered.

Eepresentatives of the Bureau have cooperated with the various

States in the preparation of specifications for railroad-track scales

and have rendered advice to State officials in reference to technical

details relating to their equipment. Assistance has also been given

to various organizations, such as the National Scale Men's Association and the American Railway Association, in the preparation of

reports, papers, specifications, and other matters pertaining to railroad-track scales.

Location, Condition, and Ownership of Track Scales Tested.

Tests have been made in 21 States and the District of Columbia,,

the States being Alabama, Connecticut, Georgia, Illinois, Indiana,

Kansas, Kentucky, Louisiana, Missouri, Minnesota, North Carolina,

New Jersey, New York, Ohio, Oklahoma, Pennsylvania. Tennessee,

Texas, Virginia. West Virginia, and Wisconsin. In these States

there were tested during the past fiscal year a total of 508 track

scales, of which 158, or 41: per cent, passed the tolerance adopted

by this Bureau. This tolerance is based on the maximum allowable

error of a weighing of 200 pounds in weighing a car of 100,000

pounds gross weight. The results obtained from the test of 149

scales included in the total number mentioned above have not yet

been compiled.

In cooioeration with the American Railway Association, 15 master

scales were tested on a schedule submitted by them and agreed to by

this Bureau. Three of the 15 master scales tested were found to

be within the tolerance during the test, and of the remainder 5 were

not in condition to make the adjustment within the tolerance practicable. The tolerance applied to these master scales allows an

error of 10 pounds in weighing a test car of 100,000 pounds.

These master scales are the practical means available to the railroads and to the various States for the standardization of test cars,, which in turn are used for testing commercial scales.

The scales tested belonged to the Federal Government, State governments, corporations, railroads, and industrial concerns.

Reports on Track Scales Tested.

Reports of track-scale tests had been rendered to the owners of

these scales, the officials of those States which have organized departments of weights and measures, officers of weighing and inspection bureaus having jurisdiction over the scales, and to chambers of

commerce. It became necessary, on account of the great pressure

of other work to discontinue this practice toward the close of the

fiscal year, but it will be resumed as soon as the present national

emergency has passed.

These reports represent a very important phase of track-scale

work. They give the results of tests in detail, show the condition?

found by careful inspection, and make recommendations for cor- recting such faulty conditions as are present.
26 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

l"he owners of the scales have been given every opportunity to

witness the tests, and the recommendations included in the reports

have been for the most part carefully carried out. In many cases new scale installations have been made as a result of the tests and

recommendations. The work thus carried on by the Bureau reduces

the amount of shortage m weight due to faulty scales; creates confidence in the correctness of the scales between the railroads, shippers, and consignees; and tends to prevent disputes as to the cor- rectness of the weights.

Technical Information Regarding Track Scales.

Several communications were prepared on various technical matters relating to scales and weighing mechanisms, which were distributed to a general mailing list of people interested in this subject.

One of these, Specifications for Class C slotted counterpoise weights

for scale testing," Commmiication BI23, gave specifications for

weights which had been found particularly suitable for conducting

tests on railroad-track scales and railroad master scales, as well as being adapted for testing other kinds of scales, such as wagon scales,

platform scales, etc. One of the most serious problems that has to be met in maintaining a railroad-track scale is the corrosion of the parts induced by

their being located in damp pits. This subject is covered in Communication B120, entitled " Protection of track-scale parts from cor- rosion," and is supplemented by Communication BI26, gi^'ing specifications for paint for use on railroad-track scales. This is a compilation of information collected by the Bureau from outside sources and from work which is being carried on by the Bureau in other

lines.

Communication B419, under the title of " General inspection and

overhauling of track scales," gives the recommendations of the

Bureau in regard to the character and frequency of scale inspection

and overhauling.

Communication B421, under the title of "Alignment," points out

and emphasizes the need for keeping the scale parts properly aligned

and makes suggestions respecting certain details.

Communication BI22. "• Maintaining the multiplication of track

scales," calls attention to some of the meelianical principles controlling the action of railroad-track scales, points out where an improvement can be made b}^ eliminating certain faidty methods of adjustments, and shows how the test can be made in conformity with cor- rect principles.

Communication B425, " Determination of actual sectional errors

in railroad-track scales," points out how infonnation necessary for

the efficient adjustment of railroad-track scales can be obtained and

properly employed.

Communication B424, entitled " Chart for adjusting levers of railroad-track scales," furnishes the practical scale mechanic in the field

the information needed by him in making adjustments without employing mathematical computations.

Communication B414, " Types of construction to be avoided."

points out certain defects, or incorrect principles, which have been

used in many scales and which should be avoided.
EEPORT OF DIEECTOR OF BUREAU OF STANDARDS, 27

Communication B-ilS, "Explanation of reports on tests made of

railroad-track scales," explains the method of presenting the information obtained in the various details of the test and inspection

as reported to the owners of the scales.

Communication B430, " Weighing by substitution," explains a method whereby accurate weighing can be carried out on a scale

which is not in itself accurate or is not intended for weighings of

such precision as can be obtained by this method.

Building for Housing Master Scale.

In order to provide a place for installing the 100.000-pound master

precision scale purchased by the Bureau and to provide facilities for

housing the field equipment while undergoing repairs and while

being standardized, a suitable building is very urgently needed.

This master scale will afford facilities both to the Government and

to the railroads for standardizing their . railroad-track-scale equipment and would also be available for the standardizing of any railroad-traek-scale equipment such as is now owned by some of the

weights and measures departments of the States. The installation

of this master scale- and building would also furnish a correct and

efficient means of weighing and standardizing large projectiles, such

as are occasionally submitted by the War and Xavy Departments,

and large guns can be weighed with precision.

Density Determinations of Materials.

During the year density determinations of 156 samples of materials

were made. These included samples of wood and special materials

whose physical properties Avere investigated for the purpose of determining their suitability for airplane construction.

An investigation of the density and thermal expansion of sea- Avater and sodium-chloride solutions was carried out, the results of

which were used for calibrating some instruments to be used in the

rapid and accurate determination of the density of sea Avater. New Sugar Tables.

A new sugar table was calculated and will be included in Circular

Xo. 44 of this Bureau when reissued. This table shows the relation

between percentage of sugar, specific gravity of solution, and degrees

Baume, and is based on the work of Dr. F. Plato." The Baume

degrees are according to the modulus 145.

Barometry, and Aeronautic Instruments.

A short time before the close of the fiscal year the barometry sec- tion was extended in scope to include aeronautic measuring instruments in general, with the intention of placing all aeronautic measuring instruments on the same basis of scientific testing as was previously the case with altitude-measuring instruments only. A number of conferences with military officials, practical aviators, and

manufacturers regarding the status of aeronautic instruments, both

here and abroad, together with laboratory experiments on A'arious

types of instruments, have served to accumulate considerable information. The infoimation thus gathered has enabled the Bureau

" Wiss. Abh. der Kaiserlichen Normal-EIchungs-Kommisslon 2, p. 153 ; 1900.
28 EEPOET OF DIRECTOR OF BUREAU OF STANDARDS.

to answer fi'e.quent inquiries and be of assistance, in turn, to other

manufacturers and military authorities. As a single example, at the

request of the joint trial board of the Army and Navy air services, a simple and definite system was prepared for the determination of

airplane altitudes during acceptance test on airplanes. The cooperation had with manufacturers of aneroid barometers has led to definite'

improvements in the quality of the instruments produced, as is shown,

in detail by the records available in the laboratory.

On account of the large demand for information on aeronautic

measuring instruments, it seems highly desirable to issue a circular

of general information on these instruments, summarizing their uses and sources of error, and announcing the procedure governing tests

at this Bureau. An outline which will form the basis of such a circular has been prepared.

Laboratory investigations in cooperation with militar}^ authorities

have been commenced. This work has included a comparative study

of the errors in the gauges used as speed indicators and also in

various tachometers.

The Bureau is represented on the appropriate subcommittee of the

National Advisory Committee for Aeronautics' in connection with

this work.

During the fiscal year routine tests were made on 2 mercurial

barometers. 2 katanoscopes. 6 statoscopes. and 3-15 aneroid barometers. The latter number includes weather aneroids, surveying aneroids, thermobarograiDhs. altimeters, and altigraphs.

Watch Testing.

Forty-five watches Avere submitted for test during the past year,

about the same number as the Bureau received for test the previ- ous 3'^ear. All of these were submitted for the class A test, and 36- per cent of the total number passed the requirements and received

a class A certificate. Thirteen of the 16 watches receiving certificates

were of American make. The rate of the Eiefler clock has continued

satisfactory during the year.

Lime-Barrel Act.

At the first session of the Sixty-fourth Congress an act to standardize lime barrels was passed and was approved on August 23, 1916.

The general provisions went into force and effect at once, and the

penal provision became effective on January 1, 1917. This law regulates the sale of lime by establishing two mandatory standard barrels

for use in interstate commerce, containing, respectively, 280 and

180 pounds net, and by requiring that packages of less capacity shall

have the net weight of the contents stamped upon them. The Bureau

is greatly in favor of the sale of commodities by weight, whenever

such a method of sale is practicable, and it heartily assisted the committee of the National Lime Manufacturers' Association in drafting

the original bill introduced into Congress and endorsed the principles represented therein.

Rules and Regulations for Barrel Laws.

The lime-barrel law provided that rules and regulations for the

enforcement of the act. including tolerances to be allowed, should be

made by the Director of the Bureau of Standards and approved
BEPOET OF DIRECTOR OF BUREAU OF STANDARDS. 29

by the Secretary of Commerce. As soon as the law was passed, the

Bureau conducted an investigation of the manner of sale of lime in

barrels and packages, and rules and regulations were finally promulgated in accordance with the provisions of the law. These have met

Avith the approval of the trade and are regulating the subject satisfactorily. A representative of the Bureau attended the annual meeting of the National Lime Manufacturers' Association and explained

the provisions of. the law and of the rules and regulations. The great

majority of the manufacturers show a most commendable desire to

understand these provisions and to comply with them.

The Bureau found the preparation of rules and regulations for

tolerances, authorized by the standard-barrel act, a difficult under--

taking on account of the dearth of information on this subject as well as the fact that it was necessary that those adopted be simple

in their application, since the tests on barrels must be made in the

field quickly and with rough apparatus. It became necessary to

conduct investigations into the formulas heretofore published, and

when these were found to be inaccurate for the type of barrel established by law a satisfactory metal standard barrel was constructed

and a new formula derived applicable to this type of barrel.

A convenient method has been developed for representing on a

single plane the variations of a quantity which depends on several

variable quantities. This method has been appliecl particularly to

the problems of representing the capacity of standard barrels cor- responding to given measurements of the head diameter, the distance between heads, and the bulge circumference. Charts for this

purpose which will be useful for those making inspections under the

new standard-barrel act have been prepared and blue prints of them

were made. The method has also been applied in slightly different

form in the preparation of charts which will be of value to the manufacturer of barrels.

With the results so obtained as a basis, simple rules were worked

out for field inspection by means of Avhich it can be rapidly and

accurately determined whether or not barrels in use comply with the

requirements of the law. The rules and regulations thus formidated

have been completed and approved, and they are now in the hands

of the printer. When these are distributed, it is believed that the

strict enforcement of the laAv Avill become practicable and that such

enforcement Avill not result in any hardship to manufacturers or

shippers.

Uniformity in Inspection of Weights and Measures.

With the rapid spread of the inspection of commercial weights and

measures throughout the icountry during the last few years, as evidenced by the passage of State laws and city ordinances on the subject, and the consequent appointment of official inspectors, the necessity of uniformitA' of laws, of specifications and tolerances for commercial apparatus, and of inspection methods is becoming more and

mor'e evident each year. The Bureau has succeeded in the past in

making satisfactory progress in regard to uniformity of laws and

of specifications and tolerances through the medium of the Annual

Conference on Weights and Measures. There has noAv developed a great demand for a manual of inspection of apparatus to the end
30 EEPOET or DIEECTOE OF BUEEAU OF STANDAEDS.

that the specifications and tolerances adopted be uniformly interpreted and enforced and the practice standardized in the various

jurisdictions. Man}' requests have reached the Bureau for a publication along these lines. There has been no publication heretofore

issued which could be recommended as satisfactory. To meet this

need and to satisf}' these demands, the Bureau has prepared material on this subject, which is now about ready to go to the printer.

This publication will probably be issued in the form of a compact

manual designed especially for field use. It is believed that this publication will satisfy the existing demand and Avill do much to V)ring

about a standard practice throughout the country, and a marked

'increase in efficiency should therefore result.

Annual Conference on Weights and Measures.

The Bureau had planned to liold the Twelfth Annual Conferenceon Weights and Measures in Washington during the month of June.

After the date had been fixed upon and preliminary details had been

worked out, the declaration by Congress that a state of war existed

caused a complete revision of the plans. It appeared to the Bureau

that no time could be devoted to this meeting by the members of the

Bureau staff on account of the great press of very urgent business

which was rapidly developing. It also appeared questionable, in

view of the general necessitA^ of economy in expenditure of money,

time, and energy, whether the results which could be accomplished

at this time Avould compensate for the expenditure involved in the

holding of the meeting.

These matters were placed before the executive committee of the

conference by the Bureau, with the recommendation that the con- templated meeting be postponed. The result was that the committeevoted unanimously to postpone the proposed meeting indefinitely, and

the Bureau believes that this was a wise decision. The meetings will

be resumed when it appears that this can profitably be done.

Cooperation with States and with Local Officials.

During the past year the Bureau cooperated with State and local

weights and measures officials by sending representatives to meetings

of officials in the States of Indiana. Michigan, New Jersey, Pennsylvania, and West Virginia. Addresses were given on subjects con- nected with the work of the Bureau and the State and local .departments, such as the test of railroad-track scales, the enforcement of

the Federal barrel laws. etc. On account of the postponement of the

national conference, the State meetings were of especial importance

this year. The State of New Hampshire joined the list of States

having adequate laws on the subject of weights and measures by

passing a bill drafted and recommended by the Bureau and based

on the model law heretofore adopted, establishing a State-wide inspection service. This State was the last one in New England which

did not furnish such protection to its citizens. Several other States

passed bills strengthening their local laws, and in still others bills

recommended and indorsed by the Bureau were considered but failed

of passage through various causes. A number of State and local

officials visited the Bureau for the purpose of obtaining assistance

and information, and as usual much information was furnished and

many problems considered through the medium of correspondence.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 31

Information Furnished on Weights and Measures Subjects.

Much information and advice on technical matters have bsen furnished, of Avhicli tlie following may be mentioned : Use of spring

scales in the United States, especially with reference to the general

points to be considered in permitting the spring scale to be used in

trade ; weighing scales and gasoline-measuring pumps furnished to

writers for use in articles for technical magazines; the design of

weighing scales furnished on request of manufacturers and private

individuals; the relative precision of equal arm balances and platform scales with reference to the weighing of precious metals; the

design of certain weighing scales for use in the Philippine Islands;

and tolerances and specifications applying to apparatus used in the

testing of water meters. Specifications were furnished for a large

automatic scale, a scale for weighing paper to be used in the Division of Supplies of the Department of Commerce, and a weighing

apparatus listed in the Government schedule of supplies. A great

amount of information has been furnished on the density, pounds

per cubic foot, and pounds per gallon of various substances; the

design of an epicyclic train for an automobile speedometer; the

adaptability of a certain device for the measurement of molasses

in tanks; the graphical methods of calculation used by the Bureau;

and the mechanical design of a paper-reeling device.

2. HEAT AND THERMOMETRY.

[Temperature, heat, heat constants, melting and boiling points, critical points, specific

heats, conductivities, and other thermal properties ot materials, including researches on

heat units and standard temperature scales, standardization of instruments and methods

for measuring temperature, determination of refrigeration data and the fire-resisting

properties of materials and other experimental work of specific value to the refrigerating

and heating industries, in the manufacture of thermal appliances, in scientific testing and

laboratories, in fire-safety engineering, and in the industries and sciences requiring

precise knowledge of temperature measurements and heat constants.]

New Regulations Governing Tests of Clinical Thermometers.

New regulations governing the testing of clinical thermometers

have been adopted, effective July 1, 1917. The former regulations

provided for tests at four points—96°, 100°, 101°, and 108° F.—and

certificates giving the corrections found were issued, provided that

the corrections did not exceed 0.3° and that the thermometers were

free from defects. Extensive inquiries among users of clinical

thermometers had shown that the corrections given on such certificates were rarely applied, and that most users preferred a

" blanket

certificate stating that the readings of the thermometers were correct. The new regulations provide for tests at tAvo points—98.6° F.

(37° C.) and 101° F. (40° C.)—and the thermometer is certified as correct if the corrections at the lower and upper test points do not

exceed 0.1° and 0.2° F., respectively. The certificate also states that

the thermometer has been aged at least one month and that subsequent changes due to aging will probably not exceed 0.1°. The latter

statement would be true only if the bulbs of the thermometers, were

made of a suitable thermometric glass, for if the bulbs were made

of soft glass the indications of the thermometer might change by a degree within a year. However, by making two tests at intervals of

a month, the inferior thermometers can be detected and rejected.
32 EEPOET OF DIRECTOR OF BUREAU OF STANDARDS.

A nevi- and distinctive certificate bearing the seal of the Bureau

of Standards has been prepared by the Bureau of Engraving and

Printing. A number of manufacturers had been issuing their own

certificates upon forms similar in appearance to those used b}' the

Bureau, and the wording of some of these certificates was such as to give the impression, at first sight, that the certificate had actually

been issued by the Bureau of Standards. It is hoped that the

Bureau's new certificate will become so well known that its distinctive character will prevent such deception.

Circular Xo. 5, Testing of Clinical Thermometers, has been re- vised to include the new regulations and will be ready for distribution early in July, 1917.

Standard Temperature Scale.

For a number of years the standard scale of temperature used bv

the Bureau in the intervals —50° to 0° and +100° to 500° C. has

been the scale defined by the platinum resistance thermometer calibrated at three points, 0°, 100°, and 444.6°, the boiling point of sulphur. The standard scale in the interval 0° to 100° has been the

hydrogen scale of the International Bureau of Weights and Measures

and is represented by the corrected indications of a number of verre- dur thermometers which had been calibrated by the International

Bureau.

The great precision and reproducibility of the scale defined by the

resistance thermometer have led to the adoption of this scale over

the whole range from —50° to +500°. It has long been known that

this scale does not differ appreciably in the range 0° to 100° from

the hydrogen scale previously in use by the Bureau. It has been

considered desirable, however, to determine as definitely as may be

the outstanding difference between the two scales, and some of the

intercom parisons have been made.

Since the work involves the determination of a minute difference,

no statement as to results will be of value until the work is completed. Assurance may be given, however, that the adoption of the

new standard scale will produce no recognizable change in the temperatui'e scale distributed by the Bureau through the medium of its

testing work.

Copper-Constantan Thermocouples.

Some progress has been made during the year in the design of a suitable inclosure for copper-constantan thermocouples and in the

preparation of couples to be used in determining a standard calibration curve for such couples in the temperature range from —200° to

+300° C. The great utility of thermocouples and their extensive

use wovdd make such a calibration very valuable.

Depression of the Ice Point of Thermometers.

The work f)n the depression and recovery of the ice points of

lhermometei*s has been practically suspended during the year, due

to difficulty in obtaining suitable thermometers made of American

thermometric glasses, which should be included in such an investigation. It is hoped that this work will be finished in the near*

future.
KEPORT OF DIRECTOR OF BUREAU OF STANDARDS. 33

Standard Boiling Points.

The method referred to in the annual report for 1916 for determining the variation with pressure of the boiling point of sulphur

has been used to determine the variations for naphthalene, benzophenone. and anthracene, over the pressure range from 700 to 800 run of mercury. The suitabilitj' of the boiling points of naphthalene and benzophenone to define standard temperatures was well

known. Anthracene has been found to be satisfactory in that a given

sample has a definite boiling point not changing with continued

boiling, but the samples used differed considerably. With the aid of

the chemical division, it is proposed to determine whether it is feasible to purify anthracene so that its boiling point may serve to define

a thermometric fixed point. The results of this work will probably

be ready for publication Avithin a year.

Standard Heat Samples for Use in Calorimetry,

The Bureau has continued the distribution of naphthalene and

sucrose as standard heat samples. The stock of naphthalene was

rerewed. Owing to inability to renew the stock, the distribution

of benzoic acid has been temporarily discontinued. A total of 239

samples, consisting of 32 of benzoic acid, 118 of naphthalene, and

89 of sucrose, was issued during the year. These samples serve an

important purpose in enabling commercial laboratories and others

to obtain reliable results in fuel testing. Cases of dispute between

buyer and seller, due to discrepancies between results of their tests,

were not infrequent a few years ago, but no such cases have come to

the attention of the Bureau for a number of years.

Standard Samples for Thermometric Fixed Points.

In addition to the service which the Bureau is able to render

scientific workers and the industries by calibrating pyrometers, there

has been a demand for some means by which the user of pyrometers

might be able to calibrate his own instruments. Pure metals of

known melting points provide a satisfactory means for this purpose,

and during the past two years the necessary materials were obtained.

The Bureau now has available for distribution samples of pure

tin, zinc, aluminum, and copper. The melting points of these materials have been accurately determined with standardized platinum

resistance thermometers, and chemical analyses showing a very high

degree of purity have been made. These materials are intended for use primarily in the standardization of rare metal thermocouples

and the samples are of suitable size (50 to 80 cubic centimeters) for

this purpose. Circular No. 66, describing the preparation and methods of use of these samples, is now in press. The distribution of

the samples will begin about August, 1917.

High-Temperature Investigations.

Some work was done on the standardization of pyrometer lamps

that had also been carefully calibrated at several industrial laboratories as a basis for the intercomparison of the high-temperature

scale actually being used in the several laboratories in important

researches, the temperature scale being that defined by the optical

pyrometer up to 2,500° C.

18532—17 3
34 REPORT OF DIKECTOB OP BUREAU OF STANDARDS.

On account of its important bearing on the use of optical methods of temperature measurements, some work was done, as time

would permit, on the change in the effective wave length of pyrometer color screens. Considerable progress has been made on the construction of an

electric furnace, capable of operation up to 1,800° C, for work on

the melting points of palladium and platinum, two very important

fixed points of the high-temperature scale.

New methods have been developed and introduced into the laboratory for testing thermocouples, which not only increase the accuracy

but very materially reduce the time required for the tests. These

have made possible large increases in the testing work accomplished.

Work has been done on the development of a " neutral " absorbing

screen for ojDtical pyrometers, such screens being generally made of

foreign glasses not now available.

In conjunction witli the metallurgical division, standard meltingpoint samples have been prepared for distribution, as explained in

the preceding section.

Low-Temperature Laboratory.

The carbon dioxide sj'stem has been operated almost continuously

to supply i-efrigeration to the thermostatically controlled baths used

for the refrigeration constants investigations and to the low-temperature thermometer comparator.

The capacity of the air liquefier has been brought up to 12 liters

per hour. Liquid air has been made 34 times during the year, as required by the various Bureau and other Government and college

laboratories. A number of demonstrations have been given to technical societies visiting the Bureau, to science classes of several educational institutions, and to other public organizations.

The air compressor has in addition been operated on 23 occasions

to supply compressed air for the low-temperature baths of the thermal expansion laboratory. The large air compressor is at present

operated by steam. Electric power should be substituted to relieve

the heavy demands on the Bureau's boiler plant.

The electrolytic gas generator has maintained a supply of hydrogen

and oxygen for general use throughout the Bureau. The acetylene

generator has been kept in operation to supply acetylene gas as needed.

A hydrogen liquefier was made in the laboratory, and an old compressor that was purchased with the plant was overhauled, a small

compressor was improvised into a vacuum pump for precooling air,

and liquid hydrogen was produced in this laboratory during the

year. Six liquid hydrogen runs were made.

Good jorogress has been made by the instrument shops on the

construction of a new hydrogen liquefier, the designs for which were

worked out last year. To produce liquid hydrogen in such amounts

as to be of real use to the Bureau's laboratories, as well as to other

investigators who may desire to avail themselves of this unusual

laboratory facility, a new 4-stage compressor, two gas storage tanks,

and some lesser equipment should be provided.

Considerable time has been given to overhauling the extensive

mechanical equipment of the laboratory. Some time has also been
EEPOET OF DIEECTOE OF BUEEAU OF STAKDAEDS. 35

given to preliminary experiments in connection with military problems.

Mercury Vapor Pump.

An improved mercury vapor pump has been developed which will

^ve a high vacuum when used in conjunction with any pump

which will evacuate to a primary pressure of 4 centimeters or

less. The pump works by two stages in connected units, each operated by mercury vapor from a single boiler, a single gas burner being

used to evaporate the mercury. The pump is simple in construction

and can be built by a reasonably skilled glass blower. Pressures

much lower than 0.0001 millimeter may be quickly reached with the

pump.

Refrigeration Constants.

This extensive series of investigations, undertaken at the request

of American refrigeration engineers, expressed through their

national associations, includes the determination of the fundamental

constants of refrigeration engineering. The work is being carried

out with the cooperation of committees of the American Association

of Eefrigeration and the American Society of Refrigerating Engineers, the members of which have kept in close touch with the work

by visits to the Bureau and by means of the reports presented before

the annual meetings of these societies b}^ members of the Bureau's

staff. The complete series of investigations contemplated under

this topic was outlined in the annual report for 1916. The work

done during the year is briefly summarized in the following sections.

Calorimeter for the Determination of Latent and Specific Heats of

Fluids.

The principle of the unstirred or " aneroid " type of calorimeter

has been embodied in an instrument especially designed for determinations of the specific heat and latent heat of several substances in

general use as refrigerating media.

Heat developed electrically in a coil located in the central axis

of the cylindical shell comprising the calorimeter is distributed by

•conduction to the calorimeter and contents, whose initial and final

temperatures when in thermal equilibrium are measured by a platinum resistance thermometer.

Heat from other sources is excluded by enveloping the calorimeter

with a metal jacket separated from it by an air space and keeping

this jacket during measurements at the same temperature as the

calorimeter surface, using multiple thermocouples to indicate this

equality.

The calorimeter is adapted for use between —50° and +50°C.

and for pressures up to TO atmospheres in experiments where the

measured heat added is used either to change the temperature of the

contents or to evaporate a portion of the contents withdrawn as superheated vapor, in the first case the specific heat and in the second

the latent heat of vaporization being obtained when proper correc- tions are made.

A paper is now in press describing the details of construction of

and the special features embodied in this instrument, the methods
36 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

of manipulation in making measurements of the heat capacity, and

giving the results of an extended series of observations in the temperature range from —50°C. to -\-50°C. to determine the heat ca- pacity of the empty calorimeter.

Specific Heat of Liquid Ammonia.

Using the above described calorimeter, the specific heat of liquid

ammonia has been determined throughout the temperature interval —45° to -(-45° C. under saturation conditions.

Two distinct and independent methods were used, each of which

avoids sources of error possessed by the other. In the first method

measurements were made of the heat added to a fixed amount of

ammonia confined in the calorimeter at saturation conditions, and

also the resulting changes in temperature. By using data for tlie

specific volumes of the two phases and the latent heat of vaporization, the corrections for vapor are applied, giving the specific heat

of the liquid, kept saturated, as a function of the temperature.

In the second method the calorimeter is kept full of liquid at a

constant pressure. The heat added to a variable amount in the

calorimeter and the resulting change in temperature were measured.

A correction for the heat absorbed by the expelled liquid, depending

on the lag of this part with respect to the entire contents, was determined by a novel thermometric device. By use of data for the latent

heat of pressure variation of the liquid, obtained from separate

measurements made with the same apparatus and material, the cor- rections for pressure variation were applied, giving an independent

determination of the specific heat of the liquid, kept saturated, as a function of the temperature.

The greatest difference between the mean results of both methods,

and the results of either method as represented by empirical equations, is less than 1 part in 1,000.

A form of empirical equation was found which, in addition to

representing closely the results in the range of temperature covered

experimentally, conforms to several theoretical considerations re- garding the behavior of substances in general when approaching the

critical temperature.

As a final result the specific heat cr, in joules (international electric

watt-seconds) per gram per degree centigrade, of liquid ammonia,

kept saturated, in terms of the temperature??, in centigrade degrees, /

is expressed in the interval —45° to +45° C. by the equation

^ = 3.1365 -0.00057j?-F-^|^

yiSo — V

A paper giving all the necessary details of this investigation has

been prepared and sent to press.

Latent Heat of Vaporization of Ammonia.

Using the above-described calorimeter, the latent heat of vaporization of ammonia has been determined throughout the temperature

interval —42° to +52° C.

An analysis of the process occurring in the calorimeter during an

experiment leads to a method of calculation of the results Avhereby

data from other sources than the direct calorimetric observations
EEPORT OF DIRECTOE OF BUREAU OF STANDARDS. 37

enter only in the computation of correction terms which can by

careful manipulation be made small.

Variations in manipulation were introduced as a means of detecting possible systematic errors, particularly in regard to the matter

of dryness of the vapor withdrawn.

The results of each of the 34 determinations agree with the mean

result as expressed by means of an empirical equation within 1 part

in 1,000. An empirical equation was found which, in addition to

representing closely the results in the range of temperature covered

experimentally, conforms to what is known about the behavior of

substances in general when approaching the critical temperature.

As a final result the latent heat of vaporization of ammonia—that

is, the heat required to convert saturated liquid into saturated vapor

at constant temperature—in joules per gram is expressed in the range

—42° to +52° C. by the equation:

i = 137.91 Vl33- 1? -2.466 (133-t?)

If the latent heat of vaporization be expressed in calorieSjo per

gram, taking 1 calorie2o=4.183 joules, the equation becomes

X = 32.968 VT33^- 0.5895 (133- 1?) Using the results obtained for the latent heat of vaporization of

ammonia together with the specific heat of the saturated liquid, the

specific heat of the saturated vapor has been computed for various

temperatures and given in a table.

A paper giving all the necessary details of this investigation has

been prepared and will be sent to press shortly, after final revision

by the editorial committee.

Latent Heat of Pressure Variation of Liquid Ammonia.

The latent heat of pressure variation of liquid ammonia—that is,

the heat gained or lost per unit pressure change at constant temperature—has been determined as a supplement to a series of specific-heat

measurements upon the same material, in order to furnish data for

correlating the measurements made at constant pressure with those

made under saturation conditions.

Three independent methods were used in the present investigation,

the first by direct calorimetric measurement of the heat transformed

in consequence of a change of pressure, the second by computation

from the expansivity directly observed with a dilatometer, and the

third by computation from the specific volume of the saturated liquid

at various temperatures and the compressibility.

The aparatus used in the measurements consisted of the aneroid

calorimeter with accessories.

The results of the three independent methods were in agreement to

the order of precision of the measurements. In temperature interval

—40° to +40° C. and range of pressures from 20

' ^

I'ilograms — square centmieters

to saturation, the results are represented by the empirical equation

, 15
38 REPORT OP DIRECTOR OF BUREAU OF STANDARDS.

where I is the latent heat of pressure variation in joules per gram for

a pressure variation of 1 kilogram per cubic centimeter. The variation of I with pressure in the range here covered was found to be

small enough to be negligible in the application of the results to the

specie-heat investigation.

Specific Volumes of Ammonia in the Liquid and Vapor Phases.

The specific volumes of ammonia in the liquid phase were measured

in the temperature interval —45° C. to -|-45° C. with an accuracy of

about 0.01 per cent. A large number of measurements of the specific

volumes in the vapor phase were made in glass containers in the temperature interval —50° C. to -|-50° C, most of the work being confined to the low temperatures. Experiments were made to determine

the magnitude of the adsorption of ammonia on glass surfaces. Tim

insertion of a large number of small, thin-walled glass tubes within

the largest glass container used in these specific volume exijeriments

increased the surface area by a factor of approximately 10. Measurements made in these two tubes of such different surface areas, in the

interval —50° C. to -)-50° C, showed that the measurements of the

specific volumes of the vapor in glass containers Avere not affected by

adsorption by an amount exceeding the experimental errors of the

specific volume determinations.

The additional measurements at the higher temperatures (above

0° C.) required to complete this investigation will, it is expected, be

completed during the present summer.

As an independent check on the results found by the above method,

an apparatus is being constructed for the determination of the re- fractive index of the vapor throughout the above temperature interval, making use of the well-known relationship between refractive

index and specific volume. It is hoped that this method will accelerate the work and increase the accuracy attainable, especially at the

lower temperatures.

Compressibility of Liquid Ammonia.

The compressibility of liquid ammonia is required in computations

relating to other important refrigeration constants of this fluid. The

special apparatus required for this work was completed, and the

preliminary measurements made with it indicate that the more important experimental difficulties have been overcome so that the

investigation can probably be completed at an early date.

Density-Temperature-Concentration Relations of Aqua Ammonia.

Work has been continued on the determination of the densitytemperature-concentration relations of aqua ammomia for solutions

of 6 to 30 per cent by weight of ammonia over the temperature

interval from their freezing points to about 40° C. The experimental work in connection with this investigation has been nearly

completed.

Pressure-Temperature Relation for Vapor in Equilibrium with Aqua

Ammonia.

The apparatus required for the determination of this relation, of

importance in the design and operation of absorption refrigerating

systems, has been nearly completed. Aqua ammonia of known con-
REPOBT OF DIRECTOR OF BUREAU OF STANDARDS. 39

centration, as determined by volumetrically measuring its constituents, is introduced into a glass vessel proA'ided with an electromagnetic stirrer which operates in the completely closed vessel without

mechanical connection to the outside. A connecting tube filled with

mercury transmits the pressure to the pressure gauge, while the

temperature control is obtained by immersing the vessel in a thermostatically controlled bath. A temperature range of —40° C. to

-|-125° C., a concentration range of to 50 per cent, and a pressure

range of to 15 atmospheres ai-e provided for by the apparatus designed.

It is hoped that the necessary measurements may be made within

the near future.

Temperature-Concentration Relation for Vapor in Equilibrium with

Aqua Ammonia.

Most of the instrument shop work in connection with the apparatus required for the determination of this relation, of imj)ortance

in the design and operation of absorption refrigerating systems, has

been completed, and it is hoped that an opportunity will be found

to make the necessary measurements during the next fiscal 3^ear. Following is a brief description of the method adopted. The

steel container, half full of aqua ammonia, is immersed in a thermostatically controlled bath. Vapor is drawn off from the top, nm

through a condensing coil, and returned to the bottom of the container. When equilibrium is established, the concentration of the

vapor phase is determined from measurements of the density of the

condensate, and of the liquid phase by density measurements of a sample drawn from the container. Densities are determined in

slightly enlarged hydrometer cells forming part of the circulating

system. The hydrometer consists of a glass float inclosing a silicon

steel magnetic armature. Gravity control, with a series of removable platinum weights, serves to determine the large steps in density,

and interpolation by means of the force exerted by a current in a

solenoid acting on the steel armature gives the small steps.

To insure equilibrium of the vapor and liquid phases, a special

device has been designed and constructed which will not only thoroughly agitate the liquid but expose a large fresh liquid surface to

the vapor. The device consists of a paddle resembling a lawn-mower

cylinder operated by a nutating rod through a flexible diaphragm

which eliminates stuffing boxes.

Specific Heats of Sodium Chloride Brines.

The measurements of the specific heats of sodium chloride solutions were carried out with the large Dewar flask calorimeter previously used in the Avork on calcium chloride solutions. Measurements were made with solutions of chemically pure salt of 5. 10, 15,

20, and 22.5 per cent of salt by weight, respectively, with solutions of

several commercial samples of sodium chloride of 20 per cent of salt

by weight, and in the temperature interval —20° C. to -\-^0° C,

The pure salt was especially prepared for this work in the chemical division, and the work on the density-concentration relation of

these sodium chloride solutions was carried out in the division of

weights and measures. The experimental work in connection with
40 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

this investigation has been completed, but time has not been available to prepare it for publication.

Chemical Investigations Relating to Refrigeration Constants.

Two investigations under the program of refrigeration constants

have been carried out in the chemical division, one relating to the

composition and testing of commercial anhydrous ammonia and the

other to the formation and avoidance of noncondensing gases in

ammonia refrigerating systems. The preparation of the pure material,—anhydrous ammonia, sodium chloride and its solutions,

ethyl and methyl chlorides,—for use in the determination of the

physical properties, has also been carried out in the chemical division. These results of these investigations are summarized elsewhere in this report.

Thermal Conductivities of Insulating and Structural Materials.

The results of measurements of the thermal conductivities of a number of insulating materials were published in the September

issue of the Journal of the American Society of Eefrigerating Engineers. Since the date of that publication, measurements have been

made on several other materials and on some 10 samples of panel

board.

The greater part of the elaborate equipment required for the determination of thermal conductivities of structural materials has

been completed in the instrument shops. The apparatus is being

adapted for measurements up to 800° C. (1,500° F.).

Fire-Resisting Properties of Structural Materials.

The object of the investigations on the fire-resisting properties of

structural materials is to furnish architects, construction engineers,

builders. State and city building bureaus, insvirance interests, and

others with fundamental engineering data relating to the behavior

and safety of various types of building material and construction

when exposed to different conditions met with in fires.

Fire Tests of Building Columns.

Many millions of dollars are spent annually on the construction of

buildings, the integrity of which, in the event of fire, is dej)8ndent on the behavior of tlie steel columns supporting the structures. Very

little engineering data are available which would permit of any

certain conclusions as to the thickness and kind of fireproof cover- ing required to render these columns safe under various conditions

of fire hazard. The requirements of city building codes on these

questions are so different that it is evident that either some codes

a]"e requiring unnecessarily thick fireproof coverings, with undue

increase in construction costs, or else other codes are requiring too

thin coverings, with undue increase in danger to the stability of the

structure under the existing fire hazards.

The fire tests on building columns are being conducted jointly by

The National Board of Fire Underwriters, the Associated Factory

Mutual Fire Insurance Companies, and the Bureau of Standards.

The present program of tests Avas formulated after consultation with

many engineers and architects interested in fire-resisting building

construction.
KEPOKT OF DIRECTOB OF BUREAU OF STANDARDS. 41

Types of Columns.—The types of columns being tested include

rolled steel sections, built-up steel sections, round cast-iron sections,

steel pipe filled with concrete, vertically reinforced and hooped concrete columns, and wooden columns. At least one of each of the

sections is unprotected, others are partially protected by filling the

reentrant portions with concrete, and others arc completely protected

by various thicknesses of concrete, clay tile, filled and unfilled gypsum

blocks, plaster on metal lath, and common brick, in accordance with

the methods commonly employed in practice.

Materials.—The materials used in the construction of the test columns and protective coatings have been obtained from various sec- tions of the country and have been selected with a view to obtaining

those representative of their respective classes.

The column coverings have been applied by experienced men in

accordance with plans and specifications drawn to secure average

results obtainable under ordinary commercial conditions.

Methods of Test.—In the fire tests the column, mounted within a

gas-fired furnace and kept under normal working load applied by

a hydraulic ram of special construction, is exposed to a predetermined

furnace temperature rise until the column fails. A record of the

temperature at different points within the furnace and at various

points within the test sample is obtained by means of suitable thermocouples. The deformation of the column from time to time is determined by means of pairs of nichrome wires inserted into the

column at a known distance apart and extending horizontally outward through the walls of the furnace, the wires being run coaxially

through fire-clay protecting tubes.

In the fire and Avater tests, the column is exposed to a furnace temperature built up at the same rate—i. e., in accordance with the

standard time-temperature curve that has been adopted for these

tests—until the desired temperature rise in the furnace is attained,

when two opposite Avails of the furnace are rolled out of position

by means of trolleys provided for this purpose and the hose stream

applied.

Status and Sequence of Tests.—The column coverings have all

been applied. During the latter part of the present fiscal year, the

preliminary work incident to adjusting burners to secure uniformity

of temperature, to securing satisfactory operation of the ram, to

calibrating gauges, etc., and to making several preliminary fire tests

on filled pipe columns, was conducted, and on June 28 the first fire test of the regular program was successfully completed. Several fire tests have been made, and they give promise of yielding results of

far-reaching importance in building construction.

The following tabulation shows the fire tests and the fire and water

tests, classified according to the tyi^e of covering:

Fire tests of columns: Number of tests. Partial concrete protection 9

Full concrete protection 24

Reinforced concrete 6

Plister on metal lath 5

Filled pipe 4

Clay 18

Gyp'ium 5

Common brick 2

Timber columns 4

Fire and water tests of columns: various types of coverings 13
42 REPOET OP DIRECTOR OP BUREAU OP STANDARDS.

No schedule has been decided upon for testing the unprotected

cohimns, it being the present plan to test them as opportunity affords.

Witnessing Tests.—Underwriters, engineers, architects, and others

having a proper interest in the subject are cordially invited to visit

the laboratories, when in Chicago, and witness one or more of the

tests in progress. The time for the tests is schedided each week in

advance and may be ascertained through inquiry by letter, telegraphy or telephone addressed to Underwriters' Laboratories, 207 East Ohio

Street, Chicago.

A brief prospectus of the proposed tests containing somewhat

fuller information than the present brief report is about to be issued.

Fire Tests of Reinforced Concrete Columns.

The program of cooperative tests, now under way at Chicago, includes but six columns of the reinforced concrete type of construction. When this program was prepared, it was, of course, realized

that the number of such tests included at the time was wholly inadequate to determine the many possible variables that enter as important factors into reinforced concrete column construction. At that

time, however, the several laboratories cooperating in the tests re- ferred to did not see their way clear to laying out a program more

extensive than the one adopted, which would require at least three

years for its completion. Accordingly, the question of planning a com'prehensive series of fire tests of reinforced concrete columns was

deferred until the tests of the structural steel columns should be

completed.

Whatever action may finally be taken with respect to the preparation of an elaborate program of fire tests of reinforced concrete

columns, the Bureau concluded that the preparation of such a program, when it is finally taken up, would be very greatly facilitated

if there were available fire tests of a number of such columns of

representative types of construction. Accordingly, during the present year, the panel furnace at the Pittsburgh laboratories of the

Bureau has been modified to adapt it to such tests, a 600-ton hydraulic ram has been installed to apply a continuous follow-up load to

the column in the furnace, and about 30 reinforced concrete columns

have been cast. The columns include square and round sections, 16

by IG inches and 18 inches diameter, respectively, by 8 feet in length,

aggregates of different types, and different methods of reinforcement. The temperature within the column, during the progress of

the test, while the temperature of the furnace is being raised at the

predetermined rate called for by the standard time-temperature curve adopted for all such tests, is measured by means of thermocouples imbedded in the columns at various distances from the

surface.

During the last few weeks of the fiscal year, several successful

preliminary fire tests were made on some extra columns that had been

cast for the purpose, in order to test the new equipment and to

standardize the procedure.

Thermal Efficiencies of Column Coverings.

A comparison of the thermal efficiencies of the materials commonly

used for column coverings has been completed at the Pittsburgh

Laboratories of the Bureau durinff the year. A short paper giving

a summary of this work and entitled "A comparison of the heat
EEPOET OF DIRECTOB OF BUREAU OF STANDARDS. 4a

insulating properties of materials used in fire-resistive construction"

was communicated to the annual meeting of the American Society

for Testing Materials in June, 1917. This comparison of the materials themselves was preliminary to the investigations relating to

the fire-resistive properties of structural units.

Solid cylindrical test specimens, 20 centimeters (8 inches) diameter

by 40 centimeters (16 inches) length, were given the same heat ex- posure in a special gas-fired furnace. The rates of temperature rise

at four depths within the specimen were measured by means of

thermocouples mounted in 6-millimeter inch) holes extending

longitudinally through the cylinder. Cylinders, similar to the cylinder under test, were placed at each end of the latter, in good contact

with its end faces, to minimize the disturbing effects of heat losses

from the ends. The materials included in these tests were: (1) Clays

of the type used in the manufacture of hollow-tile fireproofing; (2)

concretes, including two proportions of a number of aggregates;

(3) gypsums; (4) lime mortar; (5) one specimen of a new material..

The results are now being prepared for publication.

Strength of Steel at High Temperatures.

Some preliminary tests made in these laboratories two years ago

on the ultimate compressive strength of short lengths of steel tubing

showed that at 600° C. the ultimate compressive strength had decreased to 60 per cent, and in the next 50° C.—that is, at 650° C.—tO' about 30 per cent of its value when cold. On account of the great

importance of such data in their bearing on the behavior of structural

steel building construction when exposed to fire conditions, special

apparatus has been designed for a more complete investigation of

the elastic properties of metals at high temperatures. Contracts were

placed in June for the construction of this apparatus, and it is ex- pected that measurements with it may be started in the early winter.

Panel-Testing Furnace.

This furnace, together with its accessories, designed to test wall

and partition structural units as large as 12 by 16 feet, was installed

last year, and was described in the last annual report. Seven additional panel frames required to complete the plant should be installed as soon as the necessary funds can be provided. Arrangements have been made with a committee of ship 'constructors and

operators to make a few fire tests of specially constructed panels

with a view to improvement in the fire-resisting construction of

passenger-carrying ships.

Steps have been taken to secure the cooperation of prominent engineers, representatives of engineering and technical societies, and

manufacturing associations in the formulation of a comprehensive

program of tests of the fire-resisting properties of various types of

partition and wall construction. These tests are necessarily expensive, requiring as they do the test to destruction of large structural

units. Very little progress on such an elaborate program of tests

is possible until the appropriations available for the work are

-secured.

Building Codes, Information, Cooperative Work, etc. Considerable correspondence has been carried on with engineers,

State fire marshals, fire department officials, and others interested in
44 REPOKT OF DIRECTOR OF BUREAU OF STANDARDS.

fire-prevention work, and the Bureau has cooperated with committees of the National Fire Protection Association in their several lines

of work, especially with the committees relating to State building

codes, safety to life, etc., and with the Bryn Mawr Fire Prevention

Committee in their investigations on the fire hazard in relation to

factories in which women are employed.

Work has been done in preparing an index for collating information relating to the fire-resisting features of building construction

and in collecting data on the causes of fires. A section entitled " Fires in the home " has been prepared as a part of a new Bureau circular, " Safety for the household," now in course of preparation.

Activities in Technical Societies, etc. Members of the heat and thermometry division have cooperated

with committees of the Society of Automotive Engineers on various

aeronautical problems; committees of the American Society of Refrigerating Engineers on various problems relating to refrigeration

engineering, several papers being presented before that society on

the refrigeration constants investigation under way in the laboratories of the Bureau; committees of the National Fire Protection

Association, the American Society of Testing Materials, and the

Bryn Mawr Fire Prevention Committee on various problems relating to the fire hazard, safety to life, standardization of fire tests, etc.

;

the American Society of Testing Materials on the standardization of

a new flash-point tester; the joint committee of the Bureau of Standards and the Bureau of Mines on Standardization of Motor Fuels;

and with similar bodies.

Information Furnished, Reports, etc. Several hundred special letters and reports relating to the work

of the heat and thermometry division were prepared during the

year in compliance with requests for information addressed to the

I3ureau by engineers and technical men, scientific investigators, national. State, and municipal bureaus and laboratories, etc, The subjects are treated in detail below.

Instruments, Apparatus, Materials and Methods of Test.—Mercury thei'mometers, resistance thermometers, thermocouples, optical

and radiation pyrometers, including such questions as specifications,

choice of instrument, installation and protection, methods of use, precautions in use, etc., thermometer bridges and thermocouple potentiometers, thermostats, thermometer comparators, annealing ovens,

electric and gas furnaces, gas and fuel calorimeters, high-vacuum

pump, refractories, methods of testing insulating materials, refractory materials, fire-resisting properties, heat-resisting properties of

glass, etc. Scienti-fic Data.—Thermal conductivities of metals and insulators,

freezing points, melting points, specific and latent heats, heats of

reaction, heat losses by convection, and transmission of heat through

air spaces.

Properties of iJ/a^eW«?.s.---Resistance of materials to heat, expansivity and melting points of fire brick, properties of mica, heating values

of fuels, insulating value of various materials, and properties of

porcelain.
HEPOKT OF DIRECTOR OF BUREAU OF STANDARDS. 45

Gmoline and Oils.—Addition agents for gasoline, danger of ex- plosion in filtering gasoline, gasoline substitutes, motor fuels, aero

eni'ine tests, specifications for oils and gasoline, etc. Miscellaneous.—House heating, control of temperature and humidity, refrigerators, radiators, impurities in commercial ammonia,

liquid air, freezing of fire extinguishers, fireproof safe cabinets,

manufacture of various materials, etc. Heat and Thermometric Apparatus Tests.

During the year, 2,303 mercurial thermometers of various kinds

were submitted for test, of which 2,189 were certified. Among those

submitted were 215 ordinary calorimetric thermometers, C8 precision

calorimetric and Eeckman thermometers, 16 clinical standards, and

the remainder laboratory and special thermometers of various types

and ranges from below 6° to 500° C. About 2 per cent were received

broken and about 0.8 per cent were broken in the process of testing.

Twelve thousand four hundred and six clinical thermometers were

submitted for test; of these, 11,G70, or 94.1 per cent, were certified.

The percentage rejected amounted to 5.9 of the total number submitted; 1.2 per cent were rejected on account of defects of construction, 0.15 per cent because of too gi^eat difficulty in throwing back

index, and O.fi per cent on account of retreating of index ; 0.7 per cent

were received broken; 0.15 per cent were broken in testing; and 3.1

per cent exceeded the limits of allowable errors. In addition to the above there were tested in the thermometer

laboratories 14 platinum resistance thermometers, G thermocouples,

the melting point of 11 samples of naphthalene as a basis for custom

duties, and the freezing point of 4 fire extinguisher liquids.

Among the calorimetric tests Avere 2 gas and 1 adiabatic calorimeters. Two hundred and thirty-nine standard heat samples were

furnished during the year.

In the high-temperature laboratories there were tested 2 radiation

pyrometers, G optical pyrometers, 13 pyrometric lamps, 10 base-metal

thermocouples, 55 rare-metal thermocouples, 10 pyrometer galvanometers, 5 homogeneity tests of thermocouples, 2 resistance thermometers for high temperatures, 20 melting points of refractories, and 7

special high-temperature tests. In addition there were tested G21

base-metal thermocouples for the fire tests on protected steel building

columns now being cari'ied out in Chicago.

The total amount of testing done has increased very considerably over that of any preceding year. This work was done by a somewhat

smaller staff and was made possible in part by improved methods

and in part at the sacrifice of progress on important technical investigations.

3. ELECTRICITY.

[Electromotive force, resistance, current, inductance, capacity, conductivity, insulation,

magnetic pcrmeabiUty and hysteresis, and radioaciivity, including researches on electrical units and standards, measuring instruments, and methods of measurement, and the cooperation with standardizing committees of technical societies, with testing laboratories, the

electrical industries, public-service companies, and public utility commissions, municipalities, and engineers upon problems of electrical standardization, including standards of adequacy and safety of electric service.] Scope of the Electrical Work.

One of the most important functions of the Bureau with respect

to electricity and allied subjects is the establishment and maintenance of the fundamental standards upon which all measurements
46 REPOBT OF DIEECTOE OF BUREAU OF STANDARDS.

in these fields are based, including cooperation with similar institutions in other countries so as to secure international uniformity. This

includes the intercomparison of standards and extensive research in

methods of measurement and the development and improvement of

subsidiary and derived standards. These standards are utilized and

the results of the researches are immediately applied in the testing of

reference standards and instruments for manufacturers, testing

laboratories, universities, research institutions, electric utilities, utility commissions, engineering and other interests, and various agencies

of the Government.

The testing of electrical instruments and apparatus is of two main

classes. First, there is the standardization of reference standards

and precision instruments for manufacturing and other institutions

which themselves make or standardize instruments for commercial

use or which conduct research work. It is through the work of such

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

photcmetric 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 types. The

greater portion of this testing is done for the Government services,

both for obtaining information to be used in formulating specifications, and for the testing of samples of deliveries of materials purchased 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 develcpment of those phases of engineering science in

which measurement plays an important role. Electrical, radio, and

illuminating engineering interests are all serA'ed by these investigations. The Bureau also renders important service, both directly and

indirectly, to m.anufacturing and other industries. Some of this

investigational work is on the more fundamental aspects of the principles involved, so that the results may be applicable to a class of

problems, rather than being limited to the one specific problem under

investigation. The work in measurement of lights of diff'crent colors,

the correlations of magnetic and mechanical properties of iron and

steel, and study of galvanometers are examples.

The research work in radio communication, magnetism, radio

activity, and photom?try is along lines quite similar to that in the

more purely electrical measurements. Standards have been and are being developed, methods of measurement are being improved, and

important special problems of significance to the industries and in a number of cases of particular importance to the Government, are being investigated. Specific examples of the projects in hand during

the past year are given in the sections below.

Relation of the Electrical Work to the Military Services.

Toward the end of the fiscal year there was a very great increase

in the number of electrical investigations of a military character.

Most of these investigations are made at the request of the War and

Navy Departments, and are in general of a confidential character.

The special fund granted to the Bureau by Congress toward the end

of the fiscal year for military investigations has made it possible
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 47

to add a considerable number of scientific experts and assistants and

greatly to increase the work carried on. A large portion of this

work is of direct and immediate military value, and much of it will

be of permanent scientific value apart from its military us3fulness.

Silver Voltameter,

The final voltameter paper mentioned in the annual report of

last year has now been published as Scientific Paper No. 285. This

paper summarizes the Bureau's investigations on the silver voltameter, which is the primary standard for the measurement of electric

current; it also contains the specifications for the voltameter, which

the Bureau has proposed for international adoption, and a bibliography of the subject. It has not been possible during the past year

to make further progress toward the adoption of specifications by

international agreement.

Standard Cell Work.

Some further work has been done on the TVeston normal cell, especially in regard to the methods of efficiently washing mercurous sulphate, which material is the chief source of variation in the cell. In connection with an investigation relating to the cause of the

cracking of Clark cells and the best method of preventing the same,

a number of cells of this type were set up, blanks being employed

in which the platinum terminals of the zinc limbs were subjected to

the action of zinc amalgam before being sealed into the cell wall.

Although nearly a year old, none of the cells are cracked. A number of portable unsaturated Weston cells have been made, primarily

with a view to insure to the Government an adequate supply for

emergencj'^ use.

Investigation of Inductance Coils.

The research on the inductance and resistance of standard coils at

different frequencies has been continued. A careful study has been

made of the factors which cause the inductance of a coil to decrease

and the resistance to increase with increasing frequency of current.

The most important of these are (1) electrostatic capacity between

the windings, (2) energy loss in the insulating material caused by

dielectric h5'steresis, (3) skin effect in the conductors, and (4) eddy

currents in neighboring masses of metal. The effect of all of these can be reduced by proper design.

A large number of coils have been constructed and measurements

made to determine the change of resistance and inductance with frequency. Methods have been devised for determining the effect of

each of the factors enumerated above on these coils. The experimental determination of the skin effect has been found most diffi- cult. In order to check the experimental values on skin effect theoretical formulas are needed. At present the only satisfactory formulas are those which apply to a straight wire. By means of a new

method other formulas are being developed.

Study of the Electromagnet Moving-Coil Galvanometer.

The study of the electromagnet moving-coil galvanometer for

use in alternating current measurements has been completed and the

results published. (See Scientific Paper No. 297.) These instru-
48 KEPOET OF DIRECTOR OF BUREAU OF STANDARDS.

ments are similar to the moving-coil galvanometer except that use

is made of the magnetic field of an electromagnet instead of the

field of a permanent magnet. The electromagnet is excited from

a separate source with alternating current of the same frequency

as the current to be detected or measured. A steady deflection

aiDproximatelj'^ proportional to the current is produced and the

motion can be made deadbeat by use of the proper external resist- ance. Instruments with sensitivities comparable with those for the

best moving-coil galvanometers for direct current have been constructed.

A. C.-D, C. Comparator.

Precise alternating-current measurements are usually made with

an electrodynamometer which is calibrated by reference to direct

current standards. An instrument has been devised by means of

which reference is made directly to direct current. This consists of

an electrodj'namometer whose two fixed and two moving coils are connected to form a balanced Wheatstone bridge. Both the alternating and the direct current pass through the same coils at the same

time in such a manner that there is no resulting torque when the

effective values of the currents are equal. A comparator of this kind

has beea subjected to a variety of tests, and the performance is such

as to indicate an accuracy better than 0.01 per cent. This comparator can be used to measure currents up to 0.2 ampere directly,

and, by the use of standard alternating-current resistances and standard current and potential transformers, voltages and larger cur- rents can be measured.

Bridge for Testing Precision Resistance Standards.

A resistance measuring bridge, designated especially to meet the

Bureau's needs in the accurate comparison and testing of precision

resistance standards, has been constructed in the instrument shop and

laboratory. It has been thoroughly tested and found to be highly

satisfactory. In its design special attention was directed to shielding

and thermostatic control of the temperature of rhe containing oil

bath in order to obtain the highest precision attainable. Its large

range and convenience of operation permit the comparison of re- sistance standards to be made with a minimum expenditure of time

and energy. A publication is in progress describing the bridge and

the methods used in comparing standards.

Electrically Operated Tuning Fork for Time Measurements.

This device, which has been in use in meter testing for about five

years, reads directly to 0.05 second. An electrically operated tuning

fork having a period of 0.05 second closes a contact which controls an electromagnetic counting device. By using a key in this circuit

the arrangement acts as a stop watch. Special care has to be used to

drive the fork at a uniform rate. This has now been accomplished

by operating it directly from a chronometer circuit. With slight

modification it has been found feasible to use commercial "cycle

counters " in place of the special counters previously used. It has

also been found that the method can be used with a fork having a frequency of 100, thus reading to 0.01 second. Several meter-testing

laboratories have installed duplicates of the Bureau apparatus.
BEPOKT OF DIEECTOR OF BUREAU OF STANDARDS. 49

Instrument Transformers.

The accurate testing of instrument transformers is of increasing

importance on account of their use in measuring electric energy,

especially where it is sold in large quantities or at high voltages.

Some of the State public utility commissions now require the periodic testing of all instrument transformers used in the sale of electric energy. For precision laboratory work, the potentiometer

method with a vibration galvanometer as detector, has been used for

several years. For voltage transformer testing, precision cardwound resistances have now been installed, aggregating 500,000

ohms, which enables direct measurements to be made up to 30,000

volts. A similar and equal resistance used as a protecting guard

wire eliminates leakage and errors from capacity currents to earth.

A very considerable amount of assistance has been given to some

of the State commissions and to the larger central stations and

manufacturers of apparatus in equipping tlaeir laboratories for the

testing of instrument transformers. In some cases simplified apparatus for using the precision potentiometer method is being installed,

and in other cases methods devised at the Bureau for readier adaptation to commercial use have been used.

New Method of Testing Current Transformers.

A new method of testing current transformers, particularly

adapted to central-station conditions, has been developed, and the

results are now ready for publication. The same currerit is passed

through the primaries of the transformer under test and of a standard transformer whose ratio and phase angle are known. The sec- ondaries are connected in series, aiding, and the vector difference

between the secondarv currents flows in an auxiliary circuit and is

measured directly. Either a null or a deflection method may be

used, and the sensitivity is sufficient to permit the use of portable

instruments.

Remote Control System for Motor Generators.

The somewhat elaborate system of remote control of the special

motor-generator sets has proved to be very satisfactory, and a description of it has been published during the year. (See Scientific

Paper No. 291.) The system includes five motor-generator sets, and

is permanently wired to nine laboratory rooms, so that by plugging

in a special jack one may have complete control of the speed and

voltages of the set. The phase relation between voltages is included,

and in some cases rheostats for the control of auxiliary direct current

and voltage also.

Electrolytic Cleaning of Silver.

At the request of the Department of Agriculture, the Bureau

undertook an investigation of the electrolytic reduction of silver

sulphide with particular reference to household methods of cleaning

silverware by this process. This investigation has been interrupted

by more urgent work of a military character, but Avill be resumed as soon as possible. As an outgrowth of this work, a process was discovered for preparing silver sulphide in a metallic form.

1S532—17 4
50 KEPOKT OF DIRECTOR OP BUREAU OF STANDARDS.

Electrical Properties of Silver Sulphide.

Silver sulphide may be prepared in the form of short wires and

thin strips like a metal. The wire, which must be drawn hot, has

been found to conduct electricity like a metal of high resistivity and

practically zero temperature coefficient. The strip of sulphide rolled

at room temperature has a large temperature coefficient and shows

both metallic and electrolytic conduction at the same time. It has a volt-ampere curve characteristic of a pyro-electric conductor. The

resistance of these strips has been examined with both alternating

and direct current 'with the result that the alternating-current re- sistance was nearly always found to be higher than that with the

direct current, and the passage of a small alternating current of a frequency as low as 60 cycles increased temporarily the resistance of

the sulphide while a small direct current produced the opposite effect.

The results of this investigation are now in progress.

Methods of Testing Transformer Oils.

In cooperation with a committee of the American Society for

Testing Materials, a comparative study is being made of disk and

sphere spark gaps for testing the dielectric strength of transformer

oils. A carefully prepared schedule of tests on different gaps and

different spacings is being carried out in four different laboratories.

It is expected that data will be obtained which will permit results obtained on one form of gap to be interpreted in terms of other forms

of gaps, or possibly a uniform method of testing may be agreed

upon.

Radio Service to the Government.

Cooperative work with other departments and bureaus of the Government has continued during the past year as heretofore. The

lighthouse tender Orchid and the Coast Survey steamers his and

Surveyor were equipped during the year with complete radio outfits

designed and constructed by the Bureau for the special service re- quired. At the request of the Bureau of Navigation, an investigation of radio interference in the vicinity of Boston was made.

The Bureau was represented on the interdepartmental committee

to consider hew radio legislation and took an active part in the discussion and drafting of the bill which was presented to the committee for consideration.

Additional men and funds will enable the laboratory to expedite

the work on military problems and to make the laboratory more

efficient in its cooperation with the military departments of the Government. Radio signaling is playing an extremely important part

in the war, and the radio laboratory staff is taking an active part in

the development and improvement of radio apparatus for military

purposes and is endeavoring to make the work of the laboratory as

useful as possible.

Fog Signaling.

Practical tests of the radio fog-signaling apparatus and radiodirection finder developed by the Bureau were made at the Navesink

Light Station. These tests were very successful and proved conclusively that the use of radio signaling for this purpose is a valu-
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 51

able and effective means of promoting safety at sea. A board or committee representing the Navy and Commerce Departments has

been created for the purpose of considering and recommending matters rehiting to the immediate equipment of several light stations

with fog-signaling devices. The Bureau will shortly equip the

Navesink Light Station with a permanent installation.

Radio Direction Finder.

Considerable testing and designing has been done during the past

year in connection with the direction-finding apparatus with the view

of improving its usefulness and adapting it to various practical purposes, particularly those of military importance. A large number of

equipments have been manufactured and put into actual use. Radio Instruments and Measurements.

In connection with the testing of radio instruments and equipment, studies have been made of the methods of measurement at

radio frequencies. These studies continue in progress, and include

measurements of wave length, inductance, capacity, resistance, and

current over wide ranges at radio frequencies. In order to describe

the radio work of the Bureau and to present general information

on radio measurements, a circular on the subject is in preparation.

In this publication and its subsequent revisions it is planned to give

accurate and useful information on radio instruments for the benefit

of Government officers, engineers, manufacturers, and operators.

Its scope and grade of presentation are intermediate between elementary books for amateurs and the more elaborate treatises on radio

theory and practice. It includes descriptions of instruments and

methods of measurement, collections of useful formulas and data, a development of the essential theory of high-frequency measure- ments from simple but precise low-frequencv theory, the use of re- actance curves in the rapid solution of problems, and a statement

of the radio work of the Bureau.

Radio Testing.

An unusually large amount of radio testing and calibration work

has been done during the past year for the Government departments,

for commercial concerns, and for amateurs. The facilities of the

radio laboratory have been improved as rapidly as possible to meet

the increasing demand for radio-frequency measurements, and ar- rangements are being made to improve still further the methods of

testing in order that such work may be done with greater efficiency

and rapidity. Standardization and accurate testing become more

and more necessary and important as the art of radio communication progresses, and as new devices appear new methods of testing

must be developed.

Magnetic Uniformity of Straight Bars.

The effect of nonuniformity in a specimen on the accuracy of

magnetic measurements has been studied and a method has been

developed for the determination of the degree of magnetic uniformity of straight bars. (See Scientific Paper No. 295.) _A large

number of bars have been examined for magnetic uniformity, and
52 EEPOKT OF DIRECTOR OF BUREAU OF STANDARDS.

it has been found that only a very few are satisfactory for use as standards. The bars which have been found to be satisfactory have

been carefully standardized and are used for calibration and comparison work.

Development of a New Permeameter.

A new permeameter has been developed which makes possible the

rapid determination of normal induction and hysteresis on a single

specimen. (See Scientific Paper No. 306.) This permeameter

utilizes the principle of the magnetic .potentiometer. The magnetizing force is read in terms of the magnetic potential between the

ends of the bar by means of the deflection of a ballistic galvanometer

connected to an air coil upon reversal of the magnetizing current.

The induction is determined in the usual way by means of a test coil

surrounding the specimen. The apparatus is accurate within 5 per

cent of the magnetizing force necessary to produce a given induction.

This accuracy is sufficient for most work on commercial materials.

Calibration of Bismuth Spirals.

A method has been developed for the calibration of bismuth

spirals. This consists of an electromagnet with means of inserting

either a standard test coil or a bismuth spiral in the magnetic field

between its poles. The strength of field is determined by a ballistic

galvanometer deflection when the standard coil is withdrawn from

the field.

Study of the Magnetic Susceptibility of Feebly Magnetic Substances.

A method is being developed for the determination of the magnetic susceptibility of feebly magnetic substances. The susceptibility will be determined hy measuring, by means of a sensitive

balance, the pull exerted on a sample of standard form due to cur- rent in a solenoid surrounding it. Magnetic Analysis.

Magnetic analysis consists of the determination of one or more

of the magnetic properties of steel which may be taken as criteria of

its mechanical properties. The methods of magnetic analysis may

be applied to the raw material or to the manufactured product at

any stage of its manufacture, provided the test specimen is of suitable form. Even objects whose forms do not permit of accurate

magnetic measurements may permit of comparative determinations

which, by comparison with a standard, will serve as a basis for judging their quality. The magnetic properties that may be vised are normal induction, one or more points on the hj'steresis loop, such as

residual induction or coercive force, energy loss due to rotary hysteresis, and magnetic leakage under standard conditions. In a general investigation on a particular class of steel, as many of these

quantities as possible are determined for a series of different heat

or mechanical treatments, together with the corresponding mechanical properties, such as hardness, proportional limit, ductility, ultimate strength, etc. Magnetic analysis is still in the investigational stage, but considerable progress has already been made. The one-to-one correspond-
BEPOBT OF DIBECTOB OF BUREAU OF STANDARDS. 53

ence between the magnetic and mechanical properties has been es- tablished and a number of special cases have been investigated. In

particular cases a single magnetic value may be sufficient as an index

of the mechanical properties. If more information is desired, it may

be necessary to make more complete determinations. For example,

it has been found that the coercive force is a good index of hardness.

For steel of a given chemical composition, the harder piece gives a higher coercive force. In addition, it may be possible to judge of

the internal stress from the shape of the normal induction curve. In

the course of the general investigation on magnetic analysis, a number of special cases have been studied, including the following:

One Per Cent Carbon Steel.—The investigation on 1 per cent car- bon steel has been finished. The complete results will be presented in

a paper now in course of preparation. A series of sample bars were

given different heat treatments and complete normal induction and

hysteresis measurements made in the Fahy permeameter and afterwards the mechanical properties were determined. Any difference

in mechanical properties was invariably accompanied by a corre- sponding difference in magnetic properties.

Steel Rails.—The investigation on steel rails has been made by

means of a permeameter specially designed for the purpose and ex- ploration apparatus consisting of a motor-driven magnetizing solenoid which moves along the rail at a constant rate and carries test coils for determining leakage. A photographic record is made of

deflections of the galvanometer connected to test coils. Any deviation from a straight line in this record indicates a nonhomogeneity

in the rail. By means of this exploration apparatus records have

been obtained clearly showing the strain effects due to gagging, or cold straightening, commonly applied to rails. By means of the

permeameter it was possible to distinguish between rails cooled in

summer and rails cooled in winter, and therefore likely to be in a

state of mechanical strain.

Ball-Bearing Races.—An investigation has been started for the

development of a shop method for testing the hardness of finished

ball-bearing races. Measurements of coercive force have been made

by means of an electromagnet with special pole pieces and suitable

test coils connected to a ballistic galvanometer. It has been found

that the coercive force is a good index of the hardness of the ring.

Experiments are also being made on the measurement of rotary

hysteresis. This is found by measuring the torque on a ring when

placed in a rotating magnetic field. The torque is proportional to

the energy loss of rotary hysteresis and increases with the hardness

of the ring.

Small Tools.—An apparatus has been built especially adapted to

the making of magnetic measurements on small tools, such as drills,

taps, reamers, gravers, etc. Several sets of measurements of co- ercive force have been made on drills, reamers, milling tools, and the

like, and it has been found that the coercive force gives a good indication of mechanical performance and uniformity of product.

Steel Cables.—An extended investigation is planned on steel hoisting cables. It is proposed to study the effects of various factors

which may reduce the " factor of safety " of a cable and develop, if

possible, a method for determining this reduction of the factor of
54 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

safety. It is also hoped to be able to develop a method of judging the

quality of a new cable.

Repeated Stress.—A study is being made of the effect of repeated

stress on the magnetic properties of steel. The stress is applied by

means of an electromagnet device S'milar to an electrically driven

tuning fork. The bars are removed from the apparatus at intervals

and determinations made of normal induction, residual induction^

and coercive force. It is hoped in this way to be able to follow the

course of progressive failure and that this may prove to be a useful

method for checking design.

Magnetic Compass Investigation,

At the request of the compass division of the Naval Observatory,

the joint Army and Navy Board on Specifications and the Shipping

Board, an investigation has been begun on magnetic compasses. The

investigation is for the purpose of developing a standard method of

testing compasses and the preparation of specifications for the purchase of compasses by the Government. A special form of magnetometer has been devised for the determination of magnetic moment and a rotation test for pivot friction is being investigated. It

is expected that several thousand compasses will be tested in the

course of the next year. •

Increase in the Bureau's Stock of Radium.

A 49-milligram tube of radium which was loaned by the Bureau

of Mines has been of great assistance in the routine testing during

the year as well as in the study of the methods of testing. This tube

and a second tube containing about 91 milligrams of radium have

been permanently transferred by the Bureau of Mines to the Bureau

of Standards, and constitute a very valuable addition to the Bureau's

equipment for radio-activity measurements. The radium contained

in these two tubes has a market value of about $14,000.

Radium Emanation.

The study of apparatus for impregnating water with radium emanation has been continued, and the radium emanation contents of a few therapeutic solutions have been determined. Radium solutions

to serve as standards in the measurement of radium emanation have

been supplied to scientific investigators desiring them.

Radium Luminous Preparations.

Owing to the fact that the luminescence of radium luminous preparations persists for months or years and is not dependent upon a previous exposure to light, such preparations are of great value in

the illumination of signs and dials that have to be read in the dark.

They are largely used on instruments employed in aviation and for

other military uses. The Bureau began the investigation of these preparations during

the year, and now has under study 50 specimens obtained from various sources. A photometer for the measurement of the brightness

of these preparations has been constructed and described, and apparatus for the measurement of the material after it has been applied

and for the routine testing of prepared dials is being designed.
EEPOKT OF DIKECIOE OF BUREAU OP STAlsTDAKDS, 55

The manufacturers and users of these materials are cooperating

with the Bureau in this work. Conferences concerning the military use of these materials have been had with members of the Aviation

Corps and of the French Scientific Commission. Preliminary re- ports of the work have been furnished on request to the National

Advisory Council for Aeronautics and to the Signal Corps,

Radium Testing.

The amount of radium measured during the year was about 50 per

cent greater than that measured last year. It amounted to a little over G.6 grams, which, at $100 per milligram, is worth about $GGO,000.

This radium was contained in 2S8 preparations, submitted by 24

individuals or firms, and was distributed to over 79 individuals and

institutions. Of these preparations, 1 was for Porto Eico, 2 for the

Philippine Islands, 6 for Argentina, 18 for Spain, 10 for Russia, and

2 for Japan. A number of the preparations were shipped to distributing companies; in such cases the Bureau has no information

regarding the ultimate destination of the material.

X-Ray Testing.

The Bureau is installing an equipment for X-ray testing, and it

is expected that this testing will be under way by August, 1917.

The Bureau has been requested from tune to time, for the past several

years, to undertake such work, but until now it has been unable to

do so on account of a lack of funds. The work will include not only

the testing of apparatus and materials emploj'ed in the surgical and

therapeutic applications of X-rays, but also the use of X-rays in

various other problems of military value.

Improved Methods of Measurement in Photometry.

In continuation of the work in this line reported last year, attention has been given to the further development of methods of

measurement applicable to the new types of electric lamps which

are coming into very extensive use. Little new experimental work has been done in the past year on

account of the difficulties arising from the fact that these lamps

give light differing in color from that of the standards. However,

the methods of meeting these difficulties and of correction for the

peculiarities of vision of the individual observer have been tried

out in a considerable variety of practical problems. This experience

has confirmed the conclusion that the flicker photometer, used under

proper conditions, provides a fairly satisfactory^ means of measuring lights of every color. Consequently, the Bureau has submitted

to the Illuminating Engineering Society a proposal to adopt the

flicker method as the standard one for measuring the brightness of

all lights which differ in color from the fundamental standards.

A considerable part of the work on which this proposal is based

has been published in Scientific Paper No. 299.

In rating and testing ordinary incandescent lamps, it has been

customary to measure only the mean horizontal candlepower, which

is obtained by rotating the lamps while they are being measured.

This procedure can not be used with the new gas-filled lamps, be- cause the rotation changes the convection cui'rents in the gas and
56 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

consequently affects the candlepower. Moreover, these lamps have

filaments of irregular form, and the horizontal candlepower does

not bear any definite relation to the total amount of light produced.

Consequently, the only instrument suitable for measuring these

lamps is the integrating sphere, which shows by one measurement

the total amount of light sent out by a lamp in all directions. The

90-Lrich reinforced concrete sphere built at the Bureau has proved

very satisfactory. During the year attention has been given to the

conditions of operation which may affect such measurements, and

a paper incorporating the results, together with a description of this

sphere, has been nearly completed.

Spheres have come into regular use in many lamp factories, and

one of the great practical difficulties has been to obtain a strictly

colorless material for coating the inner surface. Much time has been

spent in testing commercial paints and experimental mixtures for

this purpose; this work is not yet completed, but the use of barium

sulphate with a cellulose binder made up in proper proportions

promises to be a solution for the difficulty.

In connection with the above investigation, many measurements

of the reflection factor of materials have been made, and for such

measurements new methods have been devised which it is hoped can

be developed further during the coming year.

By using the flicker method to overcome the difficulties of color,

and the sphere for comparison of spherical candlepowers of vacuum

and gas-filled standards, sets of secondarj' standards of the gas-filled

type have been established and the candlepowers repeatedly checked

by independent comparison Avith the Bureau's standards of horizontal candlepower. The performance of these gas-filled standards

has so far been very good, and similar standards have been furnished

to a number of other laboratories and to lamp factories.

Life Testing of Gas-Filled Lamps,

The life testing of gas-filled lamps was begun during the year.

These lamps have peculiarities which necessitate special methods in

the life test as well as in the measurement of candlepower. Vacuum

lamps are usually tested at voltages considerably higher than normal,

thus shortening their actual life in order to get results more quickly

and to reduce the cost of the testing. The proportion in which the

life is reduced by a given increase of efficiency has been carefully

determined, so that the normal life can be quite accurately computed

from such " forced tests." In the case of the gas-filled lamps, however, this method can not be used because at the higher temperature

the filaments are likely to sag and open up the spirals in which they

are formed. This lowers the temperature and, consequently, the lamp

operates at lower efficiency and has a life very different from what

it would have if the filament retained its normal shape. It is therefore necessary to life test these lamps at their normal operating

efficiency, although this makes the test extend over a long time.

Investigation on Flames and Gas-Mantle Lamps.

A large amount of work has been done on gas lamps. The photoro.etric methods developed for the electric lamps are applicable also

t(t gas lafnps; the difficulties to be met are not in the mere measure-
EEPOKT OF DIBECTOE OF BUKEATJ OF STANDAKDS. 57

inent of the light produced, but rather in the adjustment and performance of the lamps themselves. Economic conditions are forcing a change in the quality of gas supplied in most American cities,

and the proper readjustment of standards of quality is an urgent

problem which can not be solved without knowledge of the effi- ciency with which different gases can be used. As a part of a general investigation of this subject by the public utility staff of the

Bureau, an extensive study has been made of the effects of variation

of heating value and composition of gas on the candlepower and

efficiency of mantle lamps at various pressures and rates of consumption. The results of this investigation are now in course of preparation for publication.

In order to compare measurements made on mantle lamps at different times and places, it is necessary to know the effects of atmos-

})heric conditions on the candlepower; these effects have been determined, and the results together with similar determinations on some

flame lamps have been incorporated in a scientific paper which is

nearly ready for publication. A comparison of the results obtained

by the Bureau on the pentane lamp with those obtained in England

has shown that the outstanding differences with regard to correction

factors are undoubtedly due to the existence of a temperature coefficient, which is, however, small as suggested in previous papers of

tlie Bureau.

Tests of Miscellaneous Illuminants.

As an outcome of the tests made last year on self-lighting emer- gency lights for life buoys, the Steamboat-Inspection Service adopted

new specifications for such lights, and this Bureau has been called

upon to test a number of them to determine whether they fulfilled

t]}0se specifications.

A number of experimental searchlights intended for use on airplanes were tested for the Navy Department, and suggestions were

made regarding the construction and operation of special lamps for

such lights.

A comparative test of 12 types of hand lanterns for the United

States Coast Guard was made as a basis for specifications, which

were drawn up to cover the purchase of lanterns by the service.

]\Ieasurements were made on a large number of street-series lamps

from various municipal lighting plants, to obtain information on the

performance in actual service of tlie newer types of lamps.

Measurements have also been made on all the common sizes of

street-series lamps to determine the variation of candlepower with

current; in these measurements lamps from several different factories

have been included.

Inspection and Life-Test of Lamps for the Government.

During the year there were inspected for the various Government

departments nearly two million lamps; of these about five hundred

thousand were carbon. Eejections on account of various defects were

unusually large, amounting to about 10 per cent of the tungsten and

to about 25 per cent of the carbon. Sample lamps amounting to 2,451

(2,076 tungsten and 375 carbon) were life tested. In comparison

with recent years the results of the tests for the year show, in respect
58 BEPOET OF DIRECTOR OF BUREAU OF STANDARDS.

to both carbon and tungsten lamps, a depreciation in quality, not only

in life, but also in the mechanical features of the lamps. Ihis depreciation is attributed by the manufacturers to the unusual condition

of increased production, shortage of competent labor, difficulty in

obtaining satisfactory raw materials, etc. Realizing that these conditions were beyond the control of the

manufacturers, the Government lowered the efficiency requirements

of the specification in order that the manufacturers might be able to

meet them.

Electrical Testing.

Instruments.—Tests of electrical instruments for the public during

the year included the following: Four voltmeters, 2 ammeters, ll

wattmeters, 11 watthour meters, 11 voltage transformers, 22 current

transformers, 1 inductance coil, 8 condensers, 8 wave meters, 17 dectemeters, 1 buzzer, 7 air condensers, 49 mica condensers, 78 resistance

standards, 1 resistance box, 9 resistance bridges, 3 potentiometers,

69 standard cells, 50 incandescent lamps life tested, 4-1 incandescent

standards furnished, 41 incandescent standards tested, one portable

photometer, 6 pentane lamps, 15 street-series lamps, 3 gas-mantle

lamps, 4 lamps for certain colors of light, 77 spherical-candlepower

standards, 1 diffusing globe, and 2 lighting fixtures.

Tests of electrical instruments made for the Government during the

year included the following: Eleven voltmeters, 17 ammeters, 2 wattmeters, C watthour meters, 2 voltage transformers, 13 current transformers, 93 dry cells, 50 electrical fans, 99 inductance coils, 9 condensers, 14 decremeters, 1 resistance bridge, 2 potentiometers, 08

standard cells, 2 air condensers, 5 mica condensers, 05 airplane compasses, 489,821 carbon lamps inspected, 1,292,223 tungsten lamps

inspected, 2,451 incandescent lamps life tested, 14 incandescent standards furnished, 30 incandescent standards tested, 48 reflectors, 3

searchlight reflectors, 9 life-buoy lights, 2 portable photometers,

6 electrical standard lamps, and 2 acetylene standard lamps.

Materials.—Materials tested for the public during the year, involving electrical measurements, included the following: Seventy con- ductivity samples, 14 inductance tests, 21 iron samples for normal

induction, 4 h3'steresis samples, 20 core-loss samples, 3 miscellaneous

magnetism tests, 198 tubes of radium, 3 emanation specimens, 1 standard radium solution, activators, 2 radio-active waters, 50

luminous materials, 3 X-ray tests of powders.

Materials tested for the Government during the past year, involving electrical measurements, included the following: Fifty transformer oils, 275 rubber gloves, 31 samples of insulating tape, 11 battery renewals, 11 fuses, 23 miscellaneous insulation tests, 400 conductivity samples, 10 inductance tests, 2 hysteresis samples, 1 core-loss

sample, 10 permanent magnets, 25 tubes of radium, 17 samples of

kerosene oil, and one sample of signal oil.

Information Furnished on Electrical Subjects.

A large part of the work connected with the various investigations

and tests consists of correspondence, in which scientific and technical

information is furnished by the Bureau. Information is also frequently furnished as a result of particular requests. Assistance and
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 59

advice have thus been rendered on electrical subjects to a number of

Government departments, to various scientific institutions, nianufactiwers, public utilities, universities, and engineers.

The Bureau cooperated with various electrical engineering, technical and scientific societies, and is represented on many of their

technical committees, particularly where electrical standardization

is involved, such, for example, as the American Institute of Electrical

Engineersj the American (Society for Testing Materials, and similar

bodies.

Assistance has been rendered the Post Office Department and the

Department of Justice in several legal ca^es, involving questions of

physics and engineering, and in which fraud was charged. Sometimes the ca^es lead to ordinary court processes, and sometimes to

postal fraud-order procedures. In some cases a considerable amount

of work was involved in investigating the various technical factors

involved.

Tables and other data were furnished for a new reprint of the

Smithsonian physical tables. An elaborate handbook on electrical

wire was reviewed and corrected for a large commercial company.

Information was furnished on the available sets of tables for mathematical calculations. As a result of a request from the War Department, the Signal Corps copper-wire specifications were carefully

studied and information supplied with a view to harmonizing them

with commercial conditions.

There has been a marked increase during the past year in the number of requests for specifications and detailed information on the set- ting up of standard cells. Many users of cells have been faced with

the necessity of making their own cells because of the increased demand and a shortage in the supply.

New Fee Circular.

The seventh edition of Circular No. 6, Fees for Electric, Magnetic^

and Photometric Testing, has been prepared and issued. Ihe principal new features of the edition are a rearrangement of the instrument schedules; the addition of considerable explanatory matter re- garding the testing of instruments, meters, transformers, and resist- ance apparatus; and the provision of a separate section for radia

apparatus.

Publications on Electric Units and Standards.

Two publications have been issued on the general subject of the

fundamental electric and magnetic units and standards. The available information on th's subject has hitherto been scattered over an

extensive literature. Circular No. GO, Electric Units and Standards,

gives a compi-ehensive and up-to-date treatment of the various units

and the standards by means of which the units are maintained. This

compendium will be of use to teachers and i-tudents, to testing laboratories, and to electrical engineers. It takes the place of certain

previous publications of the Bureau dealing with special aspects of

the subject. It includes a history of the units and the evolution of

the definitions upon which the laws on electrical standards are based.

The present status of the fundamental electrical standards is described, and the laws on electrical units in the various countries of the
60 EEPOKT OF DIRECTOE OF BUREAU OF STANDARDS.

world are given. The laws of the different countries are in substantial agreement, and the various national bureaus of standards co- operate in maintaining the fundamental standards. The circular

gives conversion factors, by means of which measurements may be

expressed in any desired unit, and also gives a selected bibliography

of previous writings on electrical and magnetic units and standards.

In connection with the preparation of this circular, a critical study

was made of the various systems of units which have been proposed

from time to time as having noteworthy advantages over the commonly used system. The results of this study were published in

Scientific Paper No. 292, International System of Electric Units and

Standards. Diverse units are used to some extent at the present time,

and are a source of confusion to the student and to the engineer. As

a result of comparing all of these systems, it appears doubtful

whether any of the proposed systems of electrical units is materially

superior even in its theoretical aspects to the international system of

units in general use, and it is concluded that there would be no compensating advantages to justify the trouble and confusion which

would attend a change of units.

public Utility Investigations.

A large and important field of work, including more of engineering and field work than most of the electrical work so far described,

is concerned with the various public utilities, particularly the electric

light and power, gas, street railway, and telephone companies. The

work includes (1) scientific and engineering research, (2) the study

of public-relations questions, (3) the preparations of specifications

regarding the quality of public-utility service, (4) methods of testing

and inspection employed by municipalities and commissions, [b)

safety rules for use by the utility companies to safeguard their employees and the public, and (G) the collection and distribution of information by published papers and through correspondence.

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

done by the Bureau of Standards for the public-utility companies

for several years. The testing of electrical instruments and meters,

of gas lamps and the standard employed in measuring the candlepoAver and heating value of gas, the life testing of electric lamps, the

testing of instruments used in telephone work, research on electrolysis

mitigation, and similar investigations and tests connected with the

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

of standards of service in the various public utilities and hence the

Bureau gradually accumulated a considerable amount of information

on these questions. Such information on several phases of the work

has been collected and published from time to time, and other publications are in preparation. The work in recent years has been considerably enlarged through special appropriations for this purpose.

Gas Service Rules.

During the past year the usual amount of work in correspondence

and conferences has been given to questions of standards for gas

service and of rules in force or proposed for adoption by cities or

States. The proposed revision of the rules of the State of Washington and the new rules proposed for the State of CoU)rado were
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 61

both examined and commented on by the Bureau during the year.

A report was also rendered after investigation of gas service conditions in Rome, Ga., covering the questions of the needed improvements in the plant and distribution system in order that satisfactory

gas service be rendered in that city. This report was rendered at

the request of the Georgia Railroad Commission, which has jurisdiction in the matter.

Bureau of Standards Circular No. 32, Standards for Gas Service, has been reprinted in the third edition because of the lack of

time for preparation of a fourth edition. The fourth edition is

urgently needed in order to bring up to date the compilation of rules

and ordinances now in force and also to take account of developments in this field brought about by improvements in gas-making

methods, changed economic conditions, and numerous other en- gineering and economic influences. Particularly it is desired that

this circular be supplemented by a publication covering special

standards for fuel-gas service. This proposal, which is made to the

Bureau by certain representative gas companies, contemplates the

adoption of standards based upon novel principles. Particularly it

is proposed to charge for gas on the basis of a certain number of

cents per million heat units and to eliminate any specific requirements as to the heating value per cubic foot. Extended laboratory

investigations as to the relative usefulness of the different gases

which might be supplied under such a standard are necessitated by

this request for the cooperation of the Bureau; it is also desired by

those proposing this new type of standard that the Bureau lend the

force of its support to the new system of charging for gas. This

could only be done, however, after a careful and rather extended

investigation. This investigation is under consideration, but as yet

no arrangements have been made to undertake the work.

Standards for Gas Service as Affected by War-Time Conditions.

The abnormal condition of the labor and coal supply, unusual

high prices for raw materials, and the demand for toluol, which

can be successfully recovered as a by-product from the city gas supplies, has given unusual importance to questions of standards for gas

quality at the present time. At the request of several States and

cities, the Bureau has given special attention to these matters, and at

the request of the Council of National Defense the Bureau has

rendered one preliminary report to it upon the scope and importance

of this subject. During the crming months a large amount of time

must be devoted to these questions in order to meet the pressing

need for information that will permit prompt adjustment of matters

Avhere changes are essential or to determine in the other cases whether

any change in standard is either expedient or necessary.

Gas Laboratory Methods.

Continuing the service rendered in past years, the Bureau has furnished information from time to time as to gas-testing methods for

cities. State, and company laboratories, by answering correspondence,

by inspection of laboratories, and by conference with city and State

representatives. As one example of this work, a representative of the

Bureau spent a week or 10 days in the laboratory of the city of
>62 KEPOBT OF DIEECTOR OF BUEEAU OF SIANDAEDS.

Cleveland and made an extended report on the improvements in

laboratory apparatus and methods which would be desirable in

order to make entirely adequate for local conditions the gas-testing

facilities of these laboratories.

Relation Between Heating Value of Gas and Its Usefulness.

An extended series of experiments has been made during the past

year to determine the relation between the usefulness of gas for

mantle lighting, ccoking, water heating, and other purposes, and

the heating value of the gas. This work was conducted at the time

primarily to answer the question addressed to the Bureau jointly by

the city of Chicago and the Peoples Gas Light & Coke Co. of that

city, namely, what is the relative usefulness of gas of 565 Btu per

cubic foot and gas of 22 candlepower. The investigation included a determination of the influence of pressure, pressure variation, rate

of gas burning, adjustment of appliances, heating value and composition of the gas, and variation of heating value upon the efficiency

with which the gas could be utilized by the customer. As a result

of this investigation a report was rendered to the city and gas company of Chicago, answering specifically the questions which they

had asked. It is concluded that if the appliances are properly adjusted and the quality of the gas is uniform the heating value is a

direct measure of the usefulness of the gas for ordinary purposes

'within the range investigated. The principal advantage or disadA^antage of one quality of gas as compared with another is therefore

the result only of the greater ease of adjustment or lesser likelihood

of getting out of adjustment of appliances when using one kind of

gas than another. The Bureau, for purposes of its report, estimated

the importance of this factor for the particular gas in question.

The further work contemplated in connection Avith the investigation of the advantage of modified fuel-gas standards, as above described, will also develop further information along these lines.

Especially it is desired to study the relative usefulness of different

gases sucii as might be made commercially if the variable heat unit

standard were adopted. These would be particularly gases of low

heating value as compared with the present commercial supplies,

tind very little information is thus far available to determine whether

or not they could be used with entire satisfaction for various applications of gas. The practicability of the proposed standards depends

largely upon the result of this investigation and it is, therefore, of

great importance that this work be pressed by the Bureau in the near

future in order that the very great advantages claimed for the new

standard may be made possible in case it proves practicable to adopt

such modified requirements.

Inspections of Gas Mantle Lighting.

In connection with the investigations thus far conducted an ex- tended series of inspections of gas mantle lamps in actual service

have been made in order to determine as far as is possible the relation between laboratory experiments and practical conditions. In
KEPOKT OF DIEECTOR OF BUREAU OF STANDARDS. 63

this work about 10,000 mantle installations have been inspected in

10 large cities, and the results have been summarized in a report

now in press entitled " Gas Mantle Lighting Conditions in Ten Large

Cities in the United States." This report also develops information

of great interest as bearing upon the advantages to the customer of

regular maintenance service hj gas companies. It is demonstrated

that lamps not so maintained regularly are much more likely to be

out of order than lamps regularly cared for by the company.

Proposed National Gas Safety Code.

During the past year the proposed " National gas safety code " has

received considerable attention by the gas engineering staff, but not as much progress has been made as was anticipated because of the necessity for interrupting this work in order to carry out the investigation, already referred to, on the subject of the relative usefulness of

different qualities of gas. The part relating to gas fitting has been

submitted to representative architects and engineers, and their comments have been received. The parts dealing with the manufacture

and distribution of gas and the design of gas appliances are nearly

completed in manuscript form but have not yet been submitted to the

advisory engineers. Information for the users of gas has been substantially covered in the gas section of the circular on Safety in the

Household, and the completion of this part of the code will be a comparativeljr simple matter. It has not been possible as yet to undertake the remaining parts of the code.

Economic Importance of the National Gas Safety Code.

The Bureau of Standards in carrying out this investigation desires

to serve as a national coordinating agency to the end that the resulting code will be acceptable and adequate, not only from the standpoint of the user of gas but also of the casualty and fire-insurance

interests, the gas companies and their employees, and the gas appliance, manufacturing, and selling interests. . The need and value of such a code is so great that the various

national organizations dealing with subjects covered by the code have

appointed special committees and expert representatives to assist in

the investigation. The following organizations are now cooperating

in this work : The American Gas Institute, the National Commercial

Gas Association, the Natural Gas Association of America, the National Fire Protection Association, the Amerioan Institute of Architects, the National Safety Council, and the National Association of

Master Plumbers. In order that the Bureau may have the fullest

information on every detail of the subjects discussed, the American

Gas Institute has appointed 12 committees, 4 in each of the three

principal sections of the counti-y—East, Middle West, and Far West.

One committee in each district is intrusted with the work bearing

upon one of the principal phases of the investigation.

It has been estimated that avoidable accidents due to ignorance,

carelessness, or faulty installation result in the loss each year of hundreds of lives and the destruction of property of large aggregate

value. It may reasonably be expected that many of these losses will
64 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

be eliminated when the code has been completed and adopted

throughout the country, both because of the official enforcement of

the code and because of its educational value to gas fitters, appliance

manufacturers, utility operators, and the general public.

The code will also serve to unify practice in gas installations and

gas-company operation work throughout the country, and it is anticipated that much needed reforms will result. This uniformity of

practice will not only tend to greater safety but will also contribute

to higher efficiency. In many cases differences between the insurance

and gas-company officials can be settled by reference to the code and

thus more harmonious cooperation of the two parties can be expected.

Already several important instances have been referred to the Bureau

for consideration with a view to the settlement of differences in insurance-inspection practices or questions as to the magnitude of the fire

hazard in certain types of gas installations. In this field the services

of a recognized national authority are essential in order to standardize the practices and to make available to all the experiences obtained in the A-arious localities. The effort of the Bureau has therefore been directed not only to the preparation of the code, but to the

collection of such information as will enable it to serve as a national

coordinating agency in this field.

Electrical Service Rules.

For several years the Bureau has been studying the questions of

specifications for electric light and power service, and the requirements that should be made by municipalities or by State publicservice commissions of the public-utility corporations engaged in

furnishing such service. This study was published early in the fiscal

year as Bui'eau Circular No. 66, Standards for Electric Service.

The demand for this circular has been large, and it is gratifying

to note that the rules, specifications, and ordinances proposed have

been made the basis for State rules and city ordinances in the instances named below. During the three years that the circular was

in preparation, representatives of the Bureau attended hearings in

various States upon invitation by the commissions interested, and

assistance was given to the commissions in Connecticut, District of

Columbia, Maryland, Missouri, New Hampshire, Oregon, and West

Virginia in drafting their rules for electric service. In a number

of the States where no public-utility commission is established, city

authorities have been assisted in drafting ordinances on the regulation of electric and gas service. Louisville, Ky., has an ordinance

based on the proposals made in Circulars Nos. 32 and 56. Since the

Circular No. 56 has been issued, the proposed State rules, with neces- sary local changes, have been adopted by the Public Service Commission of Colorado, and are being made the basis of the revision of

rules now under consideration in Illinois, New York, and Washington. The Public Utilit"es Commission of the District of Columbia has adopted the Bureau's proposed specifications for the accept- ance of types of electric meters, as given in Circular No. 56, without

change.

In addition to the propof:ed State rules and specifications for ac- ceptance of types of meters, the circular contains three i-egulatory or- dinances, suggested for cities of various sizes, descriptions of commission standardizing laboratories, and a complete and exhaustive
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 65

digest of all State rules heretofore adopted and ordinances now in

force in various cities. A revised edition is now in course of preparation, and the Bureau again wishes to acknowledge the continued

cordial cooperation of public-service commissions, municipalities, and

•

public-service corporations, the National Electric Light Association,

and the Association of Edison Illuminating Companies.

Street-Lighting Service.

For a year or more the Bureau has been engaged in a study of

street lighting in its technical and engineering aspects, with pai"-

ticular reference to the requirements that should be put into contracts between municipalities and public-service corporations for

furnishing gas and electric street lighting. A number of municipal

and private plants have been inspected, photometric measurements

made, and conferences had Avith managers and illuminating engineers.

The Bureau has been receiving the hearty cooperation of municipalities and lighting companies, but the war has necessitated a discontinuance of much of the work on the part of the Bureau, and

public-utility companies also find themselves unable to cooperate as fully as they would like to do. A special committee of the Edison

Association of Illuminating Companies on street lighting will resume

its cooperation with the Bureau at a later date.

The manuscript of a circular on " Standards for street-lighting

service " is partly completed in a preliminary form. The scope and

completeness of this study of street lighting are indicated by the

following proposed table of contents

1. The purpose and problem- of street lighting.

2. The measurement and distribution of light and illumination in street

lighting.

3. Lamps and accessories used in street lighting.

4. General principles governing the design of a street-lighting s.vstem.

5. Description of typical street-lighting systems.

6. The economics of street-lighting systems.

1. Discussion of cor.tracts for street-lighting service.

8. Suggested street-lighting contracts.

9. Statistical appendixes.

As in the case of Standards for Electric Service the Bureau seeks,

while representing the public interest, to get the utilities' point of

view also, and the study of street lighting will not be published

until full discussion and cooperation can be had from public-utility

corporations, technical societies, municipalities, and other interested

parties.

National Electrical Safety Code.

The Bureau has been engaged for four years in a study of the

life hazard in electrical practice and in the preparation 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 manitfacturing companies, others being engineers and inspectors of State commissions

and municipalities. The various national associations connected with

the electrical industry have also cooperated effectively in tliis work.

The importance of having a national code uniform in all the States

18532—17 5
66 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

is realized to be quite as great for accident-prevention rules as for

fire-prevention rules, and the advantage of having such a code prepared and presented by a national agency that can study the subject

thoroughly and consult all the interests affected is obvious.

The safety code consists of four principal parts, as follows

:

1. Rules for the installation and maintenance of machinery,

switchboards, and wire in central stations and substations.

2. Eules for the construction and maintenance of overhead and

underground lines for the transmission and distribution of electrical energy and intelligence.

3. 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 employees in working on or near electrical machines or lines.

This code does not include the matter covered by the Underwriters' Fire Code, but is parallel to the latter and consistent with it. The code is intended to be adopted by State industrial and publicservice commissions and municipalities, and to be complied with by

public-service and industrial corporations. It is also intended to be

adopted voluntarily by electrical interests when the code has not

been adopted by any administrative body having jurisdiction in their

district.

The Bureau's thorough study of the diverse conditions under which

electricity is generated, distributed, and utilized, and of the effect of

the rules on operating and construction costs has secured a code

which involves no unreasonable expense, but in general assures an

adequate measure of safety and a useful standardization of practice.

The large number of conferences held in all parts of the country for

discussion of preliminary drafts of the code aided largely in its development to the point where it was possible to recommend it for

general use throughout the country. The varying conditions in

different geographical sections, and in thickly and thinly popuial^d

districts, have been given careful attention.

The code was published originally in two installments for examination and criticism; the operating rules Avere published in August,

1914, and revised in May, 1915 ; the construction rules were published in April, 1915. Both operating and construction rules, again

revised after a general conference of all interests in Chicago in the

summer of 1916, have now been combined in a single volume which

was published in November, 1916, with a recommendation for actual

field trial. It has been the intent of the Bureau as well as the desire

of all branches of the industry, that the rules should be revised and

extended as experience in their use and the progress of the electrical

industry shows revision and amplification to be to the public advantage.

National Electrical Safety Code in Practical Use.

The electrical safety code has now been adopted in one form or

another, in part or in whole, by some 14 State administrative bodies,

and is also being used by the inspection departments of many cities

and boards of underwriters. It is being utilized as a basis for a merit-rating schedule by the casualty interests, just as the Under-
REPOBT OF DIEECTOR OF BUREAU OF STANDARDS. 67

Avriters' Fire Code has been used by the fire underwriters for some

years. Such schedule rating should result in emphasizing both tlie

merits and demerits of particular installations from the safety standpoint, and tend to reduce accidents by proper financial recognition of

each improvement made. The code is also being voluntarily applied

by a large number of utilities and industrial concerns in their own

practice. It is receiving the general approval of all these interests as rapidly as its usefulness is becoming recognized, and its advantages are seen to be greater than any minor present inconvenience

which its introduction may cause. It is becoming generally understood that the stability in electrical practice provided by such a national standard also conduces greatly toward the general economy,

the necessity for which is becoming emphasized during this period of

national stress.

Scope and Application of the Electrical Safety Code.

In view of the fact that some 80 State administrative bodies and

many cities have electrical departments, it is necessary that the

Bureau send engineers frequently to different parts of the coimtry

to assist and cooperate with these administrators and other officials

who are considering the adoption of the safety code, or as sometimes

has occurred, are considering the adoption of other electrical safety

rules prepared locally.

To aid in presenting the safety code in cases where conference is

not possible with the limited staff of the Bureau, and to assist in ex- plaining the intended application of the code, a publication has been

prepared and is about to be issued entitled " The scope and application of the national electrical safety code." In this are included

brief summaries of the different parts of the code, reasons for the

character of treatment employed, some discussion of the measures

taken to secure adequacy and reasonableness, and some recommendations for the method of conducting inspections of intallations to secure compliance with the safety-code provisions. The publication

also contains descriptions of a number of typical accidents, repetition

of which would largely be prevented by observation of the national

safety code rules for construction and operation.

Inspections Under the Electrical Safety Code.

Partly to aid in further revisions of the safety code, and partly to

assist in bringing it into actual use, the Bureau is conducting a number of inspections of different electrical systems in order to compare

electrical practice in a large number of typical cases with the requirements of the code. These comparisons are demonstrating the general adequacy and reasonableness of the rules and their value in

promoting i-eliability of service as well as safety. Such comparisons

have also had the important result of interesting many engineers in

the more active application of the safety code.

The three years' preliminary study that was given to the subjects

treated in the code, the many public conferences held in all sections

of the country, and the immense amount of work done by the engi- neers who have cooperated with the Bureau, including the representatives of the large number of national and State associations

connected with the electrical industry, probably constitute a more
68 BEPORT OF DIKECTOR OF BUREAU OF STANDARDS.

thorough studj'^ and discussion than was ever given to a similar set of rules for practice before th&y were finally promulgated for use. The trial of the code is now proving the great value of this very ex- tended preliminary study, since no important errors or oversights

in the safet}^ code have so far been brought to the attention of the

Bureau, although a number of points have arisen where minor amendments can be made in a subsequent edition. The rules are proving

generally clear and workable. Eevisions will, of course, be necessary

as experience accumulates and electrical applications increase, and

these will be made after full discussion with all the affected interests.

Organizations Cooperating in the Preparation and Revision of the

Electrical Safety Code.

Among the national organizations actively cooperating with the

Bureau in the preparation, development, and introduction of the

Siifety code are the American Institute of Electrical Engineers, the

American Electric Railway Association, the American Institute of

Architects, the American Railway Association, the American Telephone & Telegraph Co., Association of Railway Telegraph Superintendents, the Bureau of Mines, the International Association of Municipal Engineers, the International Brotherhood of Electrical Workers, the National Electric Light Association, the National Fire Protection Association, Postal Telegraph Co., Underwriters' Laboratories, Associated Manufacturers of Electrical Supplies, the National Electrical Contractors Association, the Electric Power Club,

Association of Edison Illuminating Companies, Worlonen's Compensation Bureau, and the National Safety Council. It is largely

through the cooperation of these organizations that the preparation

and introduction of the code have been thus far so successful.

Electrical Protection for Householders.

The Bureau has conducted a study of electrical hazards in the

household and the means for reducing them to a minimum. The re- sults have been incorporated in an illustrated electrical chapter to

the " Household safety '* circular, now practically ready for publication. In this study the cooperation and criticisms of lighting utilities and underwriters have been received, and the publication is in

poj)ular language, calculated to appeal to the understanding and interest of school children as well as to the intelligent householder.

Special Problems in Overhead Lines and Industrial Installations.

As an outgrowth of the work of the National Electrical Safety

Code, a study of the mechanics of overhead line construction has

proven necessary, and extended tests and field measurements have

been conducted on wires and supporting structures, the results of

which will be brought together later in a publication entitled, " Engineering data on overhead lines." Work on this publication, which

Avill be of use to engineers of utilities, and particularly to engineers

of administrators, has been delayed by the limited appropriation for

studies of this kind. The advantage of these investigations for promoting the safety of the public and the advantages to the industry in

securing greater uniformity of practice are obvious, and the studies

along this line are being continued as rapidly as the facilities permit.
EEPOBT or DIRECTOR OF BUREAU OF STANDARDS. 69

A study is being made of the best methods of providing industrial

control equipment with guards or otherwise meeting the requirements of the safety code, and manufacturers' associations are heartily

cooperating with the Bureau in this work.

Electrolysis Problem Among Public Utilities.

The majority of the street railways of the country are operated on

the single overhead-trolley plan, with the electric current flowing

into the rails through the car wheels, after it has passed through the

car motors. The current then flows back to the generating station or substation by way of the tracks and earth, some of it, however,

often flowing through underground gas and water pipes and the

lead sheaths of underground telephone and electric-light cables, and

sometimes through reinforced concrete structures. The earth con- ducts electricity by virtue of its moisture and the salts dissolved in

it, which render it an electrolyte. Hence, when the electric current

flows away from iron pipes or lead-cable sheaths, it carries away iron

or lead by electrolytic action, and this in time corrodes the pipes and

shortens their useful life and sometimes completely destroys 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

have been proposed and tried, but no standard practice for the

handling of the return current has ever been agreed upon in this

country. As the electric railways have been extended and traffic

has become heavier, the volume of current handled has increased very

greatly, and the resulting destructive effects, which are cumulative

with time, have become increasingly evident. In some cases litigation has resulted between the pipe-owning companies suffering

damage and the railway companies whose current causes the trouble.

But although the courts have considered the question of legal re- sponsibility, these cases did very little to prevent the trouble in an

effective and economical manner.

Economic Importance of the Electrolysis Problem.

. The subject of electrolysis of underground pipes, cables, and other

metal structures is one which has been given more attention in recent

years than formerly, but it still does not receive the attention in many

quarters that its importance deserves. When one considers the

enormous value of the pipe and cable properties buried in the streets

of cities and forming in many cases transmission networks between

cities throughout the country, and considering further that there

are very few water, gas, or lead-cable systems which are not more

or less subject at some points to electrolytic damage from stray currents, it is possible to better form a judgment of the practical importance of this subject. The water and gas pipe systems of this

country alone have an aggregate value at the present time in excess of a billion of dollars, and in addition to this there is a vast extent

of underground lead-cable systems belonging to telephone and elec-
70 REPOBT OF DIRECTOR OF BUREAU OF STANDARDS.

trie power companies and to municipalities. In addition to these

vast properties in the earth, a considerable part of which may be

more or less subject to electrolytic damage, there are possibilities of

trouble in the case of bridge structures, portions of steel frame buildings, and piers, which are occasionally exposed to damage from this source. While the total losses due to shortening of the life of underground

pipes and cables must be considerable, such loss does not by any

means represent the total annual damage due directly to electrolysis.

It is well known that the annual loss due to leakage of water and

gas from distribution systems is very great. It is true that only a part and probably a small part of the total leakage is due solely to

electrolysis, but it is only necessary to assume that a few per cent

of the total is due to the more rapid developments of leaks caused

by electrolysis in order to make the total loss resulting from this cause run well into the millions annually.

In making a valuation of underground pipe systems, -as, for ex- ample, in the case of a valuation to be used as the basis for a transfer

of property or for rate revision, it is necessary to consider possible

deterioration of the pipes due to electrolysis, since in those localities

in which the pipes have suffered from electrolysis the actual physical

A^alue of the system will be materially reduced.

Inconvenience and Hazard Due to Electrolysis.

It is not alone the property loss, however, that makes the electrolj'sis problem one of importance. An important fact is the inconvenience to consumers of water, gas, and telephone service due

to the interruption of the service when repairs are made necessary

by electrolytic damage. Possible interruption of the service of police

and fire-aiarm systems is also one of considerable importance to

almost every mimicipality.

Wherever currents are permitted to flow on the underground pipe

systems there is the possibility of electric arcs being formed when

pipes are disconnected, or when different pipe systems make momentary contact. Accidents of this kind are rare, but they have sometimes occurred, resulting in the loss of life and a considerable damage to property. Cases have occurred also in which leakage of gas

resulting from electrolytic corrosion of the pipe has given rise to

explosions with disastrous results. Many gas explosions in basements and manholes have occurred, and although it is difficult to

determine what proportion is due to electrolysis, undoubtedly some

of them are due to this cause. A water-pipe line weakened by electrolytic corrosion may even

present a fire hazard much greater than would result fi'om interruption of water supply at normal times. In many cities it is quite

common practice during bad fires to increase temporarily the water

pressure in the district adjacent to the fire. It is very obvious that

a badly corroded water main might be capable of withstanding the

normal pressure on the system and thus give no warning of the

weakened condition of the pipe, but at the critical juncture during

a bad fire when the pressure is suddenly increased the pipe may

burst, and thus seriously hamper the work of fire fighting. It will

readily be appreciated that in any region in which electrolysis damage is known to be in progress to a greater or less extent the mains
EEPOBT OF DIRECTOR OF BUREAU OF STANDARDS. 71

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.

Methods of Mitigation of Electrolysis.

While actual dangers resulting from the presence of stray cur- rents on underground pipe and cable systems may readily be obviated, the use of improper methods may aggravate rather than

relieve the seriousness of the trouble. In not a few cases so-called

mitigative measures which were actually harmful in their effect,

either to the system to which the measures were applied or to neighboring structures, have been installed. Altogether more than 25

separate and distinct methods of dealing with the electrolysis problem have been proposed and experimented with from time to time.

Some of these are very beneficial when properly used or may become

harmful when improperly used; and others, Avhile harmless in their

effects on the pipes, may be of no appreciable value and, hence, a

useless expenditure of time and money. It is easy, therefore, to appreciate the difficulties confronting the nontechnical man, or even

the engineer who has not given special studj'- to the electrolysis ]3roblem ; and this emphasizes the need for a more general understanding

of the fundamental principles of electrolysis by officials of utility

companies operating underground pipe and cable systems.

The Bureau has been studying the electrolysis question for the

past seven years and has done a large amount of work in connection

v/ith it. The first problem investigated was that concerning the

effects of electrolysis in reinforced concrete, after which special

attention was given to electrolysis of underground pipes. This

has included laboratory investigations concerning the effects of

electric current on concrete and metal pipes, tests of pipe coverings,

the corrosion of metals in the soil, methods of measuring soil resist- ance and various other experimental phases of the work; methods

of electrolysis mitigation that have been used or proposed; field

studies in actual practice with the application of remedies; and a determination of the cost and results obtained.

Extensive investigations have also been made into methods of

electrolysis testing in the field for the purpose of establishing the

best methods of procedure in diagnosing the cause of troubles actually experienced, determining the extent to which the underground

metallic structures are being affected, and securing engineering data

on which to determine the most effective and economical measures

that may be applied in any given case to mitigate the trouble.

Recent Electrolysis Work of the Bureau.

The Bureau of Standards has made a number of electrolysis sur- veys in various cities with the view of making detailed studies under

typical conditions, the results of which could be published for the

benefit of the public. These investigations have been made in co- operation with utility companies and municipalities concerned and

largely at their expense. Complete mitigative systems have been

installed by several cities, demonstrating the most effective means

of meeting the problem under various conditions. The Bureau makes

somewhat detailed tests in each of these places about once a year to

make sure that the protective systems are being properly maintained.
72 REPORT OF DIRECTOR OF BUREAU OF STANDAEDS.

Arrangements have been made for carrying out investigations on

the three-wire system of electric railway operation. A system of this

kind has been installed at Omaha, Nebr., and a comprehensive series

of tests have been made Avith very gratifying results. An account of

these tests will be published during the coming year. The same

system is now being installed in Springfield, Mass. This latter

system was projected more than a year ago, but owing to local conditions it was necessary to defer installation until now. It is ex- pected that this system will be in operation by October, and a careful examination of it will be made by the Bureau.

During the past year brief electrolysis investigations have been

made in about 10 southern cities. Complete electrolysis investigations have been made in Montgomery, Ala.; Hamilton, Ohio; and

Omaha, Nebr. ; and reports have been submitted to the municipalities

and public utilities operating in those cities. A similar investigation

is now in progress in the city of St. Paul, and arrangements have

been made for undertaking an investigation in Duluth, Minn.

At the present time the amount of this work which the Bureau

is doing has been greatly restricted because the majority of the

members of the staff who have been engaged in this work have been

needed for work in connection with urgent military problems. Precedence will be given to these military problems as long as it is deemed

necessary, but the electrolysis work will be resumed after the existing emergency has passed.

Leakage of Current from Electric Railways.

The Bureau has continued work in regard to the effect of treated

ties on the leakage of current from electric railway lines. This work

is being done in conjunction with the forest products laboratory.

Advice to Municipalities and Corporations.

In addition to the work of the Bureau outlined above, the results

of which are being published from time to time for general distribution, the Bureau renders an important service to the public

through the advice given to municipalities and corporations by cor- respondence and personal consultation. Frequently representatives

of utility companies and cities come to Washington for personal

interviews relating to various phases of the electrolysis and publicutility problems.

Lightning Protection.

Considerable work has been done in the direction of preparing

. specifications for the protection of buildings against lightning, but

owing to the emergency growing out of the military situation it

has been necessary to suspend this Avork temporarily. A little later, as soon as opportunity affords, this work will be continued and

specifications will be prepared for protecting different kinds of buildings and other structures, so as to make it easier for architects and

owners who wish to place lightning protection on different types of

structures to do so as efficiently and economically as possible.

Investigations on Grounding of Secondary Electrical Circuits.

Grounding the secondaries of transformers and other parts of

electrical systems to protect persons and property from electrical
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 73

dangers has, in recent years, become an important item of consideration to power companies. In view of the lack of readily accessible

information on this subject the Bureau began in 1915 an investigation with the object of presenting in a suitable form the data then

available, and supplementing it as far as seemed necessary with

laboratory and field work. This investigation has been carried far

enough to enable the preparation of the technological paper, soon to

be published, which covers the following topics: (1) Eesistance of

ground connections; (2) their uses and service conditions; (3) different forms of ground connections and the electrical characteristics

of each; (4) mechanical construction; (5) inspection and testing;

(6) fire hazard and interference Avith service; (7) costs; (8) bases

for specifications; and (9) field measurements of the resistance of

ground connections.

Experimental Study of Telephone Apparatus.

With the funds at present available, progress in this important

and most widely used branch of public-utility service must neces-,

sarily be slow. The increasing attention devoted to the subject by

public-service commissions and the general public interest in this

field make it desirable that increased funds be provided for this

work.

Attention has first been directed to the establishment of a standard

for the measurement of telephonic transmission efficiency, which in

the interest of uniformity and in order to avoid all possibility of dispute relative to transmission measurement, should be in the custody

of the Federal Government. The Bureau is now in position to make

measurements of transmission efficiency and has made considerable

progress in the development of an improved standard of transmission.

A large number of comparisons of the efficiency of transmitters and

receivers of different makes have been made wheii using the voice

as a source of sound, and in addition a study has been undertaken

of the effect of the length of subscriber's lines in common battery systems with relation to the efficiency of transmitters of various types

and makes.

In order to interpret the results of transmission measurements intelligently, even in the case of the relatively simple circuit employed

in the definition of the transmission standard and particularly in the

much more complicated circuits met with in actual practice, a thorough understanding of the theory of transmission engineering

is necessary. A study has been made of the theory of transmission over uniform and composite lines; artificial lines; the effect on

transmission of the electrical constants of the terminal apparatus

in their relation to the constants of the lines to which they are con- nected ; the effect of line apparatus such as repeating coils, and

other means of connecting two portions of a telephone circuit, as well as signalling apparatus. Such studies lay the foundation for

the formulation of the conditions to be met to give the maximum

transmission efficiency at a given frequency.

This work must be supplemented by experimental work which has

already been begun at the request of operating and manufacturing

interests. Owing to the complexity of the present-day telephone
74 REPORT OF DIRECTOR OP BUREAU OP STANDARDS.

circuits, this is a laborious undertaking, involving not only the development of suitable methods of measurement and the making of

measurements under the manifold conditions met in practice, but

also the determination of the electrical constants of representative

types of telephone apparatus under service conditions. Such work

will not only be of great general value, but its bearing on the consideration of questions raised before commissions as to the feasibility

of physical connections between different telephone systems is also

manifest. The work involves the measurement of alternating currents, voltages, frequencies, and phase relations in the telephonic

range.

The development of a method for determining telephonic transmission efficiency by other than speech tests is deemed essential.

Such a method is much needed because speech tests are not entirely

satisfactory on account of relatively large errors of measurement

(due in considerable part to variations in the carbon transmitter of

the standard circuit), especially where it is a question of determining

the effect of small differences such as those involved in determining

the influence on transmission of repeating coils, condensers, and

other apparatus used in talking circuits.

On account of resonance phenomena, especially in receiver and transmitter diaphragms, single-frequency measurements can not be satisfactory. It is therefore necessary to base results on measurements

at three or more selected frequencies combined in accordance with

the amplitude and frequency characteristics of speech. The determination of these characteristics is a fruitful field for further

investigation.

In order to carry on effectively the investigations outlined, considerable specially designed apparatus must be acquired, and the

personnel in charge of this work must be considerably enlarged.

Telephone Service Standards.

The investigation of the principles underlying the definition of

telephone-service standards is of the greatest importance to State

public-utility commissions as well as to the millions of telephone

users throughout the United States. In order to secure results of

greatest value, it is necessary to enlist the cooperation of the telephone industry, which will of course be benefited by such work. In

view of this fact the Bureau confidently counts upon its wholehearted support.

Submarine Telegraphy.

In connection with a fraud order case of the Post Office Department in which the Bureau was asked to cooperate, a study of cable

signaling and a portion of the broader field of transient phenomena

were taken up. Of particular interest in this connection is the effect

of terminal apparatus, cable relays, and amplifiers and the Squier

rhethod of alternating-current signaling, especially as related to the

speed of working. Experiments were made to demonstrate the

impossibility of claims to the effect that telephonic communication

could be had over long lengths of submarine cable of the types now

in use. Numerous tests by the aid of a 1,000-mile artificial cable

clearly indicated that the telephonic transmission apparently obtained is not true cable transmission and is easil}^ explainable by
REPORT OF DIRECTOR OE BUREAU OF STANDARDS. 75

leakage and unbalanced capacities to ground. The results obtained

are all in conformity with theory.

Relation of the Bureau to Municipalities and Public-Service Commissions.

In many States the public-service commissions have set standards

of service, and the Bureau has cooperated with most of those that

have done so. In other States the railroad or public-service commissions have taken no action in the matter, although having authority to do so. Again, in some States there are no public-service

commissions to issue regulations or to inspect the quality and safety

of the service rendered by the various utilities. In any case the cities

and towns must look after their own interests, in whole or in part,

and frequently have taken up such matters very successfully. Where

there are well-equipped and active State commissions, which have

adopted rules and are ready to hear complaints regarding rates or

service, a very large responsibility rests even in such cases upon the

municipalities. Few State commissions will ever be likely to have

a force of engineers and inspectors large enough to enable them to

take the initiative in every case and relieve the municipalities of all

responsibility. On the contrary, if the municipalities are active and

enterprising in their own behalf, and if the larger ones have wellequipped public-utility departments which can prepare the city's

complaints or requests and take them up to the State commissions

for hearing and adjudication, the State commissions would be better

able to serve all the municipalities of the State, and the municipalities would enjoy in large measure the advantages as well as the

responsibilities of home rule without its greatest disadvantages.

But for most cities and many commissions it is a difficult matter

to judge as to the quality of service rendered by its utilities. The

studies made by the Bureau are a great help in this connection, but

much remains to be done. It will conduce to fairness and a good

understanding to have the subject studied further and as definite

and complete specifications as possible made available for all

branches of public-utility service.

Obviously, it will never be practicable for any State commission

or city to handle these questions alone. Though they possess large

and able engineering staffs or employ specialists for each separate

problem, the question of what is good service or whether the service in

any given case is adequate, safe, and satisfactory can be settled only

by reference to what is done under similar circumstances 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 exjDerience of the entire country.

The Bureau has been doing this for several years, and although it

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

done enough to demonstrate the practicability and acceptability of

the method. The success and approval which the work has met so far fully justifj^ its greater development.

Necessity for Increasing the Public-Utility Work of the Bureau.

The sum available for the public-utility work of the Bureau during

the current fiscal year, including a special appropriation for the

safety work, is $65,000. Many of the States spend more than this and
76 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

some States 5 or 10 times as much. The people of the United States

spend about $2,000,000,000 a year for the service of the public utilities, or $20 per capita per annum. This includes the telephone, gas,

electric light and power, electric-railway transportation, and miscellaneous utilities, not including the steam railways. The States

through their public-utility and railroad commissions spend about

$4,000,000 a year regulating the utilities and railroads and the cities a large amount in addition, but very little of this is spent for re- search. A considerable sum could profitably be spent annually in an

efficiently conducted cooperative study of the conduct of such utilities,

defining standards of service, preparing safety rules, assisting in

local studies as to service, acting as referee or adviser in cases of

dispute, serving as a clearing house of information on all publicutility and associated engineering questions, helping to secure uniform methods of accounting (especially where public-service commissions are not yet established), carrying out laboratory tests and

investigations to answer difficult questions, and making it possible

for rules as to service and safety to be kept revised up to date after

they have once been formulated and adopted. Such work carried

on with the cooperation of the utility companies and commissions

requires a great many conferences and discussions and the harmonizing of cliiferences of opinion. Many such differences of opinion

are due to lack of precise information. Often experimental or

other studies clear up such differences and bring about uniformity

of practice.

A Federal bureau well equipped with men and apparatus, and

permitted to work in the verj^ Avide field of public utilities (outside

of railroad transportation and such subjects as the Interstate Commerce Commission is concerned with) can accomplish great good

for the public. It does not appear to be overestimating the value of

such work to say that an average benefit equivalent to 5 per cent

of the sum now paid for the service would result. It seems conservative to suppose that such benefit in improved efficiency and

better service would seldom be less than 2 or 3 per cent and sometimes

as high as 10 per cent. Five per cent of $2,000,000,000 is $100,000,000

per year, and this appears to be a reasonable estimate of the possible

value of the service being considered, assuming such service to be

efficient and ample. One cent a 3^ear per capita is only a hundredth

part of this sum, and this does not seem too much for the people to

spend cooperatively through the Federal Government to accomplish

this result. Considering the enormous cost of public-utility service,

it does not appear to be desirable to continue spending so much

without a greater effort to derive the benefits possible from a just

and adequate system of public-utility regulation.

The money value of proper regulation of the utilities is not the

only benefit to be derived therefrom, however. The increase of

safety is another consideration difficult to estimate in dollars and

cents. Still another advantage, more difficult to appraise but not

difficult to appreciate, is the favorable influence on State and municipal government. Unregulated utilities sometimes control municipalities ; improperly regulated utilities are sometimes forced to resort

to questionable methods of self-defense. Public officials charged

with the duty of regulating public utilities, but not provided with

the means of doing it equitably and effectively, ai'e at a serious dis-
KEPOBT OF DIRECTOR OF BUREAU OF STANDARDS. 77

advantage and frequently can accomplish nothing. The eagerness

with which public officials with whom the Bureau has cooperated in

the past have sought reliable information and tlieir appreciation of

the work of the Bureau indicate that if this Avork could be greatly

enlarged and made available in a larger number of cities and States,

it would be of immense economic importance and by establishing a

better understanding between utilities and the representatives of the

public woidd have a salutary effect upon municipal government. It

would also benefit the public utilities themselves, partly by increasing their efficiency and partly through the increased confidence of

the public in the fairness and efficiency of this arrangement.

4. LIGHT AND OPTICAL INSTRUMENTS.

[Wave length of radiation (visible and invisible) ; color, relative emissivity, reflectivity,

and absorption of materials for light and other radiation; transparency; and radiation

constants, including experimental researches required in determining the optical constants

of materials and of radiations; in developing optical standards of performance or quality

of optical products for manufacturers, technical experts, and research laboratories; in the standardization and testing of sugar and other materials by optical means; and in standardizing the measurement and specification of colors for such industries as dyes,

paints, ceramics, paper, inks, etc.]

Determination of Standard Wave Lengths.

A considerable number of very accurate determinations of wave

lengths of light is required for spectroscopic work. Such wave

lengths will serve as standards for the accurate measurement of wave

lengths corresponding to lines in the spectra of the chemical elements. These standard wave lengths are measured by the interferometer method and are expressed in terms of the red radiation of cadmium which is the fundamental spectroscopic standard. During the past year the Bureau has increased the existing

number of secondary standards by measuring the wave lengths of 12

cadmium lines. 21 helium lines. 56 neon lines, and 24 argon lines.

These lines are quite sharp and it has been possible, therefore, to

measure the wave lengths with an accuracy of one part in four or

five millions. They are scattered throughout the spectrum from the

ultra-violet, at 2900A, into the infra-red to 8500A. The abbreviation for angstrom is A and its length is one ten-millionth of a

millimeter.

The study of numerical relations between different spectrum lines

has been begun in connection with these accurate wave-length measurements. A well-known series formula has been tested with the

helium wave lengths and the results are contained in Scientific Paper

No. 302. In the neon spectrum it was discovered that frequencies

corresponding to several groups of lines are the same to one part in

about five millions. These are no doubt the most exact numerical

relations ever observed among spectrum lines and are of great importance from both practical and theoretical standpoints.

Infra-red Photography.

A large part of the spectroscopic investigations of the Bureau

during the past 3^ear has been in the longer wave regions of spectra

to which ordinary photographic plates are insensitive. These regions

were recorded on ordinary plates which were stained with certain

photographic dyes. The comparative efficiency of several dyes as
78 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

red and infra-red sensitizers for photographic use has been investigated ; pinacyanol was found best in the orange and red, and dicyanin

most valuable in the adjacent infra-red spectral regions. With the

use of these dyes the wave-length interval which may be photographed Avith ordinary plates is easily doubled and extended to about

2000A beyond the visible limit in the red. The value of these dyes

has been demonstrated by the photography of the infra-red spectra

of laboratory sources, of the stars, and of the sun. At present these

photographic dyes are not made in this country, although their im-'

portance in scientific work and in the industries warrants the ex- penditure of a large amount of effort upon their production and

upon the search for new ones. Up to the present there has been comparatively little accurate

spectroscopic investigation of light waves longer than those of

yellow light. The important red and infra-red regions have never been explored with the same completeness as the other regions. It

is very desirable that this be done in order to establish a broader

basis for spectroscopic chemical analysis as well as for more general

reasons. Ordinary plates stained with dicyanin have been used at

the Bureau to photograph the arc spectra of 20 of the chemical elementSj including the alkali metals, the alkaline earths, and elements

commonly found in iron as impurities. The photographs were made

with a large concave grating and the wave lengths were determined

relative to the international secondary standards in the spectrum of

the iron arc. The wave lengths photographed with these stained

plates range from .5600A to 9600A and the results for 10 chemical

elements are published in Scientific Paper No. 309. Frequency differences of pairs of lines in the spectra of sodium, potassium,

rubidium, caesium, and copper are shown by these wave-length meas- urements to be constant, in most cases, to 1 part in 100,000 in the

number of waves per centimeter. Comparison of the spectra made

it possible to detect many impurities in the elements, and this feature

of the work will, no doubt, be of considerable importance in chemical

analysis. The spectra of neon, argon, krypton, and xenon gases

were also photographed in the infra-red by means of the grating and

dicyanin-stained plates. Many new lines were thus recorded and

some striking similarities in the spectra of these gases were found.

In the xenon spectrum Avhat appear, by analogy with the other rare

gases, to be the principal lines were observed for the first time.

Through the courtesy of Director E. C. Pickering, of Harvard

University, the 24-inch reflector of the Harvard College Observatory was used for the purpose of extending the photography of long

wave lengths to stellar spectra. The results have shown the feasibility of extending observations on stellar spectra to greater wave

lengths than has heretofore been possible. A new absorption band

was photographed at the end of the visible spectrum and later laboratory experiments at the Bureau have confirmed the conjecture that

this is due to titanium oxide. There is found in this experience an- other example of the stimulating effect of celestial spectroscopy on

laboratory investigation. The general conclusions of this work

may be stated as follows: (1) Many stellar spectra possess suffi- cient intensity in the region of Avave length 8000A (infra-red) to

enable this portion of the spectrum to be photographed on plates
BEPORT OF DIRECTOR OP BUREAU OF STANDARDS. 79

sensitized with dicyanin; (2) in favorable instances stellar spectra can be recorded to wave length 8500A or possibly to even greateiwave length; (3) the region of stellar spectra beyond 7000A contains features of importance to astrophysics, especially in the case of the red stars. The Johns Hopkins University kindly placed at the disposal of

the Bureau, a suitable grating and auxiliary apparatus for the photography of the solar spectrum. Dicyanin-stained plates made it possible to record the spectrum of the sun from the red at 6800A into

the infra-red at 9600A. The dispersion and fine detail of these photographs is nearly comparable with that of Professor Rowland's

map of the solar spectrum from the ultra-violet limit to the visible

red. The measurement of wave lengths corresponding to the absorption lines and comparison of these with the lines obtained from

laboratory sources will make possible additional identifications of

chemical elements in the atmosphere of the sun.

Refractive Index and Dispersion of Air.

It has become necessary to investigate the optical properties of the

air, since they have not been determined with sufficient thoroughness for the reduction of some of the wave-length measurements.

For example, the difference in the index of refraction of the air for

different wave lengths must be taken into account in the measure- ment of secondary standards of wave length, and for the proper

discussion of numerical relations among spectrum lines it is neces- sary to reduce wave lengths which have been measured in air to their

value in a vacuum.' This requires a knowledge of the index of re- fraction of air of various densities for a large range of wave lengths.

Over 1,000 observations have been made on the index of refraction

of air for wave lengths from 2500A to 9000A, which is the entire

spectrum range easily recorded by direct photography. These observations were made for several temperatures between 0° C. and

60° C. and for several pressures ranging from zero to one atmosphere.

Spectroscopic Analysis.

The spectroscopic method of analysis has some advantages, within

certain limits, over the chemical method of analyzing chemical compounds. In some cases the quantity of the sample is too small for a

successful analysis by chemical means. The spectroscopic method

can be used to test the presence of all the constituents of a compound

in a single small sample, while the chemical method often requires

several portions of the material, each one of which is separately ex- amined for a certain element or group of elements. Furthermore, a spectroscopic analysis can generally be made much more quickly

and easily than a chemical analysis. For these reasons considerable

time has been given to developing both qualitative and quantitative

analyses by spectroscopic methods.

A large number of standard samples of alloys Avere prepared by

metallurgists and carefully analyzed by chemists. The spectra of

these definitely prepared and analyzed samples were then compared

with the spectra of samples of unknoAvn content. In this way the

unknown specimens were analyzed with accuracy. This method has

been especially valuable in the analyses of boiler safety plugs of
80 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

fusible tin. Several hundred such plugs have been examined and

found to average 0.2 per cent copper, 0.1 per cent lead, 0.05 per cent

zinc, and 0.07 per cent iron. The specifications for these plugs allow

0.3 per cent total impurities and the spectroscopic method is now

A^ery simple if the impurities fall Avithin this range. An analysis

of 10 plugs can be made in about 90 minutes in this way, while the

chemical methods require about three days. Thirteen aluminum

alloys Avere examined spectroscopically and the type of alloy determined. Thiii;een samples of zinc ore, electrolytic zinc, and muds

from electrolytes were examined for rare elements by spectroscopic means. A number of iron, steel, brass, platinum, and glass samples

have also been examined. All the glass samples contained lithium

and it was found possible to make comj)arative determinations of

the sodium and potassium content which were roughly in accord

with the chemical analyses.

The spectroscopic method of analysis is extremelj^ sensitive and

often detects impurities Avhich escape the chemical method. In

cases Avhere the chemical quantitative analysis can not be replaced

by the spectroscopic method, a rapid preliminary spectrum qualitative analysis often saves the chemist much time.

Rare Gas Discharge Tubes.

The spectra of the rare gases can only be examined by confining

small quantities of the gases in glass or quartz tubes and .sending

an electrical discharge through them. The design of these tubes is a matter of much importance and has received considerable attention

at the Bureau. Both glass and fused quartz tubes containing hydrogen, helium, and argon have been made. Some of these tubes were

required in work at the Bureau, and several were furnished to other

Government bureaus and to scientific institutions. It was found

possible to make excellent discharge tubes of argon directly from

the air. A small bulb of quartz or Pyrex glass was filled with

calcium chips and attached to a tube containing air. Maintaining

the calcium at a temperature of about 300° C. for several hours

abstracts all of the nitrogen and oxygen and leaves quite pure argon

in the tube at about the proper pressure for spectroscopic Avork.

The frequent requests for the rare gases and their great importance

and promise in scientific Avork demands the production of neon,

argon, krypton, and xenon on a larger scale.

Solubilities in the Sugar Group.

The data obtained on the solubilities of sugars and on the influence of foreign substances upon these solubilities have an industrial as well as a scientific importance. The preparation of the

sugai'S of commerce always involves their crystallization from impure solutions. The quantity of sugar Avhich can be obtained hj a

crystallization depends upon its solubility in the presence of the

particular impurities Avhich occur in the crude materials. Cane and

beet molasses are simply solutions of sugar in Avater containing large

quantities of mineral salts and invert sugar.

During the past year the Bureau has investigated the solubilitj^

of sucrose in the presence of glucose and invert sugar (invert sugar,

obtained by the decomposition of sucrose, is a mixture of glucose
REPOET OF DIRECTOR OF BUREAU OF STANDARDS. 81

and levulose), and the solubility of glucose in the presence of

sucrose and levulose. The results thus far obtained show that the

conclusions reached by previous investigators are incorrect. The

investigation' is being continued and the influence of mineral salts

IS being studied. In this manner it is intended to stud}^ individually

the constituents that make up the complex systems in molasses.

Influences of Temperature on the Speed of Inversion of Sugar.

Under the influence of acid, sucrose decomposes to form a mixture

of two sugars, namely, glucose and levulose. This mixture is called

invert sugar. The decomposition or " reaction " occurs with a measurable velocity which is very sensitive to temperature influences.

This reaction is used to estimate sucrose quantitatively when other

optically active substances are present. The technique of this method

is in need of improvement on account of its Avide application in the

analyses of sugar mixtures. As a first step the velocities of the reac- tion for the range of temperature employed have been determined.

The expei^ments consisted of measurements of reaction velocities at

relatively great velocities. The results of the experiments showed

that the velocities could be expressed by a mathematical formula

which had been derived theoretically by previous workers.

Specifications for Commercial Grades of Sugar.

One of the most important problems confronting the sugar industry, both from the standpoint of the manufacturer and the public,

owes its origin to the absence of definitions or specifications of the

various grades of commercial sugars. This matter has been brought

to the attention of the Bureau a number of times. Considerable

difficulty has been experienced by manufacturers of cand}^ due to

variations in the sugar, it frequently being necessary to modify the

formulas of candies on this account. In another instance the Navy

Department was furnished with an inferior grade of sugar by a contractor. Recently the question of specifications which would define

die different grades of commercial sugars, both white and brown

(or soft) sugars, has been brought up by domestic producers.

From preliminary investigations the Bureau is convinced that, owing to the variations in quality which now exist, the work of preparing rigid specifications for the grades currently on the market will

be considerable, but once such specifications are established the uncertainties of quality in the different grades of sugar will be practically eliminated. The Bureau hopes to be able to carry out this

important investigation in the near future.

Basis of Saccharimeter Standardization.

The results of the Bureau's investigation of the present basis of

standardization of saccharimeters were set forth in the last annual

report. The most important item was the correction of an error of over one-tenth per cent in the 100-degree sugar point of the

saccharimeter scale, the net result being the saving of $60,000 annually in the revenue of the Government from imported sugar and a much larger gain to the producers of sugar. Owing to the present

conditions in Europe, the Bureau has abandoned hope for the present

of a correction of this error by the international committee which

18532—17 6
82 KEPOET OF DIRECTOR OF BUREAU OF STANDARDS.

was appointed to make a recommendation regarding the matter.

Despite this fact the Bureau has conckided that it is no longer warranted in standardizing sugar-testing apparatus on , a basis now

known to be in error. Accordingly, certifications will be changed at

an early date to the new value of the 100-degree sugar point of the

saccharimeter.

Constants of the Quartz-Wedge Saccharimeter.

The Bureau has described, in Scientific Paper No. 268, the preparation of pure sugar and the many critical tests made to establish its

purit3^ This substance was used to fix accurately the 100 per cent

point of the saccharimeter in order that sugar analysis in connection

with the sugar industry and for tariff assessment purposes might rest

on a proper basis. Sugar in common with a large class of other substances alters or " rotates " the plane of Aubration of plane-polarized

light b.y an amount almost exactly proportional to its concentration.

This property has been utilized for the exact analysis of these substances in instruments called saccharimeters and polarimeters.

It is now proposed to extend the investigation to the remainder

of the sugar scale in order to ascertain the corrections to be applied

for changing concentration of sugar. Thus the 80, 60, 40, and 20

per cent points on the scale will be determined with the same precision as the 100 per cent point. It is hoped in this way to establish

a valid working basis for accurate sugar analysis.

At the same time precision measurements of the rotations of the

sugar solutions will be made on the polarimeter. These measure- ments Avill supply data for the calculation of the variation of the

specific rotation with changes of concentration of the sugar solution.

Rotation of Quartz at High Temperature.

The natural and magnetic rotation of light by crystalline and

quartz, and the magnetic rotation of light by the amorphous quartz

have been studied at high temperatures. Additional knowledge of

the properties of quartz is of special importance from the theoretical standpoint, because of its extensive use in polariscopes and

other optical instruments and because of its relation to the problems

involved in the study of the history and formation of the earth.

Crystalline quartz has a transition point at about 575° C. ; at this

temperature the crj'stal changes over into another crystal form.

This is shown in the experimental curve of the natural rotation by an

abrupt change of direction. Above this point the temperature has

little effect upon the rotation, Avhile just below it a small change in

temperature causes a large change in the rotation. On the other

liand, the magnetic rotation of both the amorphous and crystalline

forms is found to be practically independent of temperature, increasing very slightly as the temperature rises and showing no

change at 575° C. « Magnetic Rotation by Magnetic Substances.

A research has been undertaken on the magnetic rotation of

metallic films, namel3\ iron, iron oxides (hematite, magnetite, etc.),

and nickel, from room temperature to temperatures as high as possible (about 1,000° C. in some cases). This Avork has opened a field
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 83

which has heretofore been unexplored. The behavior in this region

of the substances mentioned is of great theoretical importance, existing theories having been based on the experimental facts observed at

ordinary temperatures.

The experimental dilRculties involved in carrying on the work are

necessarily numerous and difficult to overcome. A powerful electromagnet placed between the polarizer and analyzer of a very sensitive

polariscope was used, the pole pieces being perforated to allow the

beam of light to pass parallel to the lines of force through the substance in the magnetic field. Specially constructed furnaces to obtain the high temperatures were required. These furnaces had to be

small enough to go in between the poles of the magnet and yet give

a uniform temperature. Thermocouples and a sensitive electrical

apparatus were utilized for taking temperature measurements. A

gas-tight furnace was necessary for the work on the metallic films, so that the film could be kept in an atmosphere of hydrogen, oxygen,

or other gas during the experiment, a long quartz and glass tube

extending through the magnet being used for this purpose. The

film to be observed was placed inside this tube, and the furnace was

slipped over the outside of the tube containing the film in such manner that the film was in the center of the furnace and in the center

of the magnetic field.

The results obtained show that the magneto-optical effect (rotation of the plane of polarized light) becomes zero in the ferromagnetic substances at the temperatures at which their magnetic properties are lost. This effect is especially clear and sharp in the case of nickel, the rotation falling abruptly to zero at about 360° C, the

temperature at which nickel loses its magnetism. In the case of iron,

the phenomena are much more complex. With the increase of temperature from room temperature, the magnetic rotation begins to

decrease rapidly. It rises again somewhat at about 300° C, indicating that some change or transformation is taking place, then gradually falls off again to practically zero at about 780° C, the transformation of iron. The films were deposited electrically on thin

quartz plates placed in a high vacuum.

Bureau of Standards Baume Scale.

The existence and use of over 20 different Baume scales have caused

considerable confusion and misunderstanding in the industries. These

are arbitrary scales, used indiscriminately, in the determination of

the density and the percentage of sugar in solutions. The great importance of correcting this situation is shown by the action of the

Association of Official Agricultural Chemists at their last meeting in

recommendng that the Bureau of Standards make a study of the

problem, with the object of establishing a suitable standard Baume

scale for use in the sugar industries. The Bureau has already recognized the need of such a scale and had previously conferred with

several persons prominent in the field of sugar analysis. The matter

was taken up in cooperation with the division of weights and measures of this Bureau and a new Baume scale, together with tables for

its use giving eqviivalents in per cent sugar and specific gravity, was

constructed. The new scale is to be used at 20° C, the standard temperature in sugar analysis.
84 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

The advantages of the new Bureau of Standards Baume scale are shown by the following: (1) It is based upon the specific gravity

values of Plato, which are considered the most reliable of any available; (2) it is based on 20° C, the most convenient and widely ac- cepted temperature for sugar work; and (3) it is based on the modulus 145, which has already been adopted by the Manufacturing Chemists Association of the United States, the Bureau of Standards, and

by all American manufacturers of hj^drometers.

Standard Glassware for Customs Laboratories.

The Bureau has undertaken to interest American manufacturers in

the production of standard glassware, owing to the difficulty experienced by the Treasury Department in obtaining suitable glass apparatus for use in the testing of raw sugars. Specifications were sent to a number of makers and very favorable replies were received. It is thought that, in future, the American manufacturers will be able to

meet the demand for these supplies.

Circular on Polarimetry.

There has been a rapid growth in recent years in the applications

of polarimetry to the arts and sciences, with a proportionate increase

in the requests made upon the Bureau for information. Circular 44,

on Polarimetry, which includes a resume of the work done at the

Bureau of Standards and elsewhere, has to a large extent furnished

the desired information. It has been revised and considerable matter

added in the appendixes. The new material comprises 10 tables, including the new Bureau of Standards Baume scale for liquids heavier

than water, results of recent researches, a consideration of the polarization of low-grade products, a resume of the work of the International Commission for Uniform Methods of Sugar Analysis, and

amendments to the United States Treasury Department Sugar Regulations.

Polarimetric Tests of Raw Sugars.

The -present disturbed conditions in freight transportation have

resulted in raw sugar importations being entered at unusual points.

However, the samples received by the Bureau were mainly from the

larger customs ports. There were 1,243 samples of raw sugar tested.

About 50 per cent were direct polariscopic determinations of the

quantity of sucrose present, and the remainder were tested for the

percentage of moisture in addition to the direct polarization.

Sampling Molasses in Tank Cars,

Owing to the conditions prevailing in water transportation, large

quantities of molasses are now shipped in tank cars from Cuba by

way of Key West. The merchandise is loaded in the cars at Habana

and transported to Ke}^ West by ferries and. thence, to numerous

points in the country by rail. The securing of representative samples

of molasses in the tanks has proven a difficult matter, and a member

of the Bureau was sent to Key West to study the subject. This study

has resulted in the preparation of suitable regulations covering the

sampling of molasses in tank cars, and these regulations will he is- sued as soon as their preparation has been completed.
BEPORT OF DIKECTOK. OF BUREAU OF STANDARDS. 85

Polarimetric Tests of Molasses.

The constantly increasing use of Cuban molasses in the United

States has made it imperative that the Bureau give further consideration to the testing of this material. A number of samples have

been studied and reported on. As yet, however, no satisfactory

method for an accurate determination of the density of molasses has

been found.

Information Furnished on Polarimetry.

A further increase in the diversity of the information requested by

the general public was noted during the past year. A considerable

demand for information regarding older types of saccharimeters and

other apparatus has arisen. The abnormal domestic sugar production and the scarcity of all kinds of sugar-testing equipment has

made it possible for the Bureau to furnish much valuable assistance

to the industry. In special cases the Bureau has departed from its

established policy and made accurate adjustments on saccharimeters

so as to render them fit for service. The manufacture of polariscope

tubes and cover glasses, inaugurated by the Bureau in this country,

has been continued with success. Present conditions have emphasized the importance of having all classes of scientific apparatus

manufactured in the United States.

Polarimetric Testing.

During the year there were tested about 500 cover glasses for

optical homogeneity, and 24 quartz-control plates were standardized.

Standard Samples.

Seventy-three standard samples of sucrose and seven samples of

dextrose were distributed during the year. These materials are used

principally for industrial and scientific purposes, such as the standardization of saccharimeters and for the determination of the heat

value of fuels.

Installation of Sugar Laboratory at Savannah, Ga.

A large sugar refinery was completed during the past year at

Savannah, Ga. This made it necessary to establish a customs laboratory at that port for the purpose of collecting the revenue on sugar.

The Bureau^ was requested to supervise the equipment and installation of this laboratory, which it did satisfactorily.

Supervision of the Customs Laboratories of the Treasury Department.

The work of supervising the operation of the customs sugar laboratories has been continued with gratifying results. It was found

necessary to modify the existing regulations owing to abnormal sugar

importations, and as far as data are available, this has apparently

been accomplished with no diminution in the accuracy of the tests. The port of Savannah has been added to the list of those ports sending samples dailj'^ to the Bureau for check analysis. The work of

assisting the Treasury Department in improving the equipment, personnel, and efficiency of its general customs laboratories is progressing very satisfactorily.
86 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Color Standards Investigation.

For several years past urgent demands for advice and assistance

in measuring and specifying the colors of light sources and materials

have been made on the Bureau by various industrial and commercial interests. To enable the Bureau to develop methods and instruments to meet these needs, Congress made a special appropriation

for the fiscal year ended June 30, 1917. Some of the fundamental

work necessary in this investigation has been initiated and is in

progress.

While some of the tasks comprehended in this investigation may

be said to be completed or nearly so, the investigation is of such

nature and magnitude that it must be continued several years before

a general definitive report can be made. Besides undertaking the

fundamental research problems in this investigation, a great deal

of time and attention has been given (1) to the technical application

of colorimetry and spectrophotometry to specific problems in industry, (2) to routine colorimetric testing by methods already established, and (3) to furnishing, on request, information and advice

in regard to color measurements and color standards. In fact the

aggregate attention necessarily given day by day to specific tasks

and current correspondence of this kind is so great as to impede

very much the progress on the main inA^estigation and delay its completion. The instruments and methods used in this work are also

applicable to certain military and naval problems; and in the present emergency these resources of the Bureau are being utilized, even though it involves delay in carrying out the fundamental work of

the color standards investigation as originally planned, ^ome features of the colorimetric work are reported upon in the following

paragraphs. 1

Testing, Extension, and Improvement of Spectrophotometric

Methods.

The physical basis of color specification is spectrophotometry. By

this is meant the measurement of photometric intensities as a series

of points through the spectrum. For example, suppose a yellow

glass is to be tested: qualitative examination by means of a spectroscope will show that it transmits red, yellow, and orange light quite

freely, while transmitting less green and little or no blue and violet.

The function of spectrophotometry is to determine quantitatively

the transmission (ratio of light transrhitted to light falling on the

glass) for each kind of colored light separately. Now each kind of

colored light in the spectrum can be specified definitely by its wave

length ; and the result of such a test is a curve showing the relation

of transmission to wave length. Such a curve determined with ac- curacy by reliable methods constitutes a unique specification of the

color of the sample.

As mentioned in the report for last year, there was need of improving the methods for these determinations, particularly in the

blue. This work has been undertaken as planned, and the spectrophotometric methods in use at the Bui'eau have been further tested

and checked. Test specimens of various colors of glass have been

carefully prepared and measured on one instrument (Konig-Martens

spectrophotometer) at the Bureau. Through the courtesy of the
EEPOBT OF DIRECTOK OF BUREAU OF STANDARDS. 87

physics department of Cornell University, these same specimens

have been again measured by a representative of the Bureau on an

instrument of another type (Lummer-Brodhun) at Cornell and their

transmissions for blue, violet, and ultra-violet also determined by a photographic method (Hilger sector apparatus). This procedure

makes jDOSsible the detection of small errors and gives much more

confidence in final results. Such counterchecking of results will be

continued and elaborated. Apparatus is being installed for spectrophotometry by another independent method using the photo-electric

effect.

Fundamental Data Needed for Reference in Colorimetry.

The establishment of color standards and standard methods of

color specification will require the compilation, systematization, and

publication of a great deal of data and information, some of which

is now available in the literature, and some of which will have to

be obtained experimentally. It is planned to publish a circular and

other special papers on this subject as soon as such matter can be

put in proper form.

A great deal of time has already been given to compiling, computing, tabulating, and plotting data so as to have it in form con- venient for reference in colorimetric investigations and tests. Among

the data so prejoared in tabular and graphic form during this year

are the following

(1) Spectral Distribution of Radiant Power in Various Light

Sourees._—The color of a light source is determined by the relative

amounts of radiant power of different wave lengths which it emits.

Thus, if the power emitted by a source consists entirely of radiation

of a single definite wave length, it will give rise to a saturated color

sensation corresponding to that wave length. If it contains radiations of various wave lengths, the color will be determined by the

relative amounts of radiant power of these different wave lengths.

The sun and all incandescent solids (carbon particles in oil and gas

flames, the filaments in electric lamps, etc.) emit radiation of all

wave lengths over a wide range but in very different proportions for

the different wave lengths. Thus, while all of these lights are approximately " white," some are very bluish relative to others. It is

of fundamental importance in colorimetric work to have available

for ready reference curves showing the radiant power of various

sources as a function of wave lengi;h (spectral distribution curves).

Such data have accordingly been collected and plotted to a uniform

standard scale. Also, the theoretical distribution of a perfect radiator at various temperatures, as given by the formulas of Wien and

Planck, has been newly computed and plotted, using most recent

data. The compilation of these data is of sjDecial interest because

its consideration and discussion are necessary preliminaries to the

definition of " white light," one of the first steps in the establishment of color standards.

(2) Spectral Disfrihution Com/puted from the Rotatory Dispersion

of Quartz.—" Color screens " of known spectral transmission—that

is. having a knoAvn transmission for light of each wave length in the

visible spectrum—are of great importance in colorimetry. Colored

glasses and dyed gelatine films are used to some extent for this
88 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

pui'iDose, but they have the disadvantage that their spectral transmissions and, consequently, their colors are not readily adjustable at

will nor conveniently and certainly reproducible. An optical system

composed of a quartz plate between two nicol prisms may be used

as a color screen, and the color is adjustable by varying the thickness

of the quartz plate and the angle between the principal planes of the

nicol prisms. The spectral transmission of such a system can be

computed a priori with great precision, but such computations are exceedingly long and tedious. It has therefore seemed advisable to

compute a great number of such curves for different constants and

preserve them for ready reference. About 600 curves of this kind

have now been computed and plotted.

(3) Special Tables of the Trigonometric Functions Used in Photometry.—In some photometric and colorimetric work the computations require frequent use of the square of the sine of an observed

angle read in degrees and hundredths of a degree. There being no

tables of this kind of sufficient accuracy available, a set has been

computed as follows

{a) 0° to 10° at intervals of 0°.02 to six decimal places.

(&) 10° to 80° at intervals of 0°.02 to four decimal places,

(c) 80° to 90° at intervals of 0°.l to four decimal places.

The computation and copying of these tables has been carefully

checked and photographic copies made for current use in the laboratory. They will possibly be published later. In the meantime a limited number of photographic copies may be supplied to those in

need of such tables.

Less extensive tables of the fourth power of the sine and the square

of the tangent have also been prepared.

Establishment of Working Standards of Color.

Although the ultimate terms of a color specification shovild be absolute without reference to material colored standards or particular

apparatus, nevertheless, working standards are important and essential. Some of the working standards of color to which attention is being given are the following

(1) Light of Known Standard Color.—For the time being, working standards of light of known color have been provided by empirically color matching (by voltage adjustment) a number of

vacuum tungsten lamps with a standard acetylene flame of previously

known spectral distribution. These lamps have been numbered and

marked and are preserved as the laboratory working standards for

light of this color.

(2) '''"Artificial Daylight.''^—Another necessary working standard is " artificial daylight." There are on the market several combinations

of lamps and colored glasses intended to give " artificial daylight."

These have been developed by different experts on the basis of some- what different definitions of " daylight." It is important that these

be intercompared and that a standard " artificial daylight " be

adopted. An investigation of these " artificial daylights " is now in

progress at the Bureau.

An original method of producing " artificial daylight " has also

been devised at the Bureau and developed theoretically and experimentally. It has been found by theoretical computations that the
EEPOKT OF DIEECTOR OF BUREAU OF STANDARDS. 89

spectral distribution of daylight can be approximately matched by

light from an artificial source modified by transmission through a quartz plate between nicol prisms. The constants for such apparatus have been determined theoretically and the color match verified

experimentally. A paper on this subject is in preparation for publication.

(3) Colored Solutions.—Various colored salts ahd other substances

in solution have some value as vrorking standards of color. It is important that substances used for this purpose have their spectral

transmissions accurately determined. During the year the spectral

transmissions of a number of such solutions, submitted to the Bureau

and proposed as color standards, have been determined. A few

other solutions have also been examined, and it is planned to extend

this investigation to include as many as possible reproducible colored

solutions of known purity and concentration. While there exist considerable previous data on this subject, they are largely qualitative or only crudely quantitative. The purpose of the present investigation is to obtain quantitative data of the highest possible accuracy.

(4) Colored glasses.—Colored glasses are also important as working standards of color. An extensive collection of colored glasses of

standard manufacture is being made. The specimens are carefully

prepared, marked, and filed in a systematic way. Their spectral

transmissions are also being carefully determined by different methods and filed so as to be available for ready reference. It is intended

to continually extend and augment this collection of glasses and data.

Design and Construction of Colorimetric Apparatus.

The design and construction of new instruments and apparatus are important features of the color standards investigation. The construction of the variation of thiclmess color comparator, mentioned

in the report of last year, has been completed in the instrument shop

of the Bureau, and the instrument has been installed and adjusted in

the laboratory. The construction of a new trichromatic colorimeter

is in progress.

Specific Technical Applications of Colorimetric Methods.—The

end and purpose of the color standards investigation is to provide

standard methods and apparatiis needed to make color specifications

possible in science, industry, and trade. The following are the important specific problems to which attention has been given this

year.

1. Specification of the Saturation of Yellow Tints in Butter and

Oleomargarine.—Frequent and persistent demands have been made

on the Bureau to draft a form of specification which would be suitable to define rigox'ously in law a limiting value of what, in common parlance, may be called the " color," the " depth of color," the

" strength of color " or the " yellowness " of butter and oleomargarine. In compliance with this demand, methods have been developed and definitely formulated, and a report on this subject has been

published. (See Technologic Paper No. 92.)

2. The Photometry of Lights of Different Colors and the Specifications of Their Colors.—The determination of the relative candlepowers of lights of different colors is one of the most difficult problems of photometry, while the convenient specification of the color
90 EEPOET OF DIRECTOR OF BUREAU OP STANDARDS,

of a light is the fundamental problem of color specification. A

method which greatly facilitates the solution of both of these problems has been developed and tested. Reports upon this method have

been made to the American Physical Society. December, 1916, and

April, 1917, and published in the proceedings of those meetings in

the Physical Review.

3. Examination of Glasses Intended to Protect the Eyes from

Harmful Radiation.—There are on the market a number of glasses

recommended to protect the eyes. At the request of the American

Medical Association, the Bureau has undertaken to determine the

spectral transmissions of a considerable number of these glasses. A

great deal of this work has been done and a report will probably be

published during the coming year.

4. Color Grading of Cottonseed Oil.—The investigation of the

color of cottonseed oil has been continued, but has been delayed

owing to the impossibility of securing certain needed apparatus.

The effect of temperature on the rate of fading of the oil has been

studied. It is found that the color fades, even in vacuum-sealed

cells, somewhat more rapidly at temperatures from about 20° to

35° C. than below this temjDerature.

5. Transparency of Paper and Tracing Cloth.—To meet the demands of purchasers and manufacturers, a standard method for

grading the transparency of paper and tracing cloth has been formulated and liublished. (See Circular No. 63.)

Information Furnished on Color and Color Specifications.

Information relative to color, color specifications, and related

toi^ics has been given to man^^' applicants, both in personal conference

and by correspondence. Among those to whom such information

was furnished are the following: Refiners of oils, railway officials,

architects, teachers of art, packing companies, textile manufacturers, paper manufacturers, manufacturers of optical apparatus,

chemists, physicians, and the following departments and bureaus of

the Government: Bureau of Chemistry, Navy Department. Bureau

of the Census, Bureau of Lighthouses, Interstate Commerce Commission, Bureau of EntomologA% and other branches of the service.

Tests of Color, Spectral Transmission, and Transparency.

A considerable number of tests of color, spectral transmission, and

transparency have been made during the past year for the Navy

Department, the Post Office Department, the Department of Agriculture, and other branches of the Government service, as well as for a number of industrial concerns and other interests.

Turbidimetry.

Turbidimetry is the quantitative measurement of turbidity. A

medium is made turbid by the presence of minute particles in suspension, which scatter light in all directions. The quantity of scattered

light can be taken as a measure of turbidity. A turbidimeter based

upon this principle has been designed and constructed by the Bureau.

With it every liquid examined, even the purest doubly distilled water,

has been found turbid. The turbidity of relatively clean air is quite

appreciable. The instrument measures a definite optical quantity,

namely, the fraction of the incident light scattered by the turbid

medium in a particular direction. This is the simplest quantitative
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 91

meaning that can be attached to the word turbidity used in an optical

sense. The turbidimeter can, therefore, be used to define a new

standard of turbidity.

The turbidity standard used in water analysis, as a guide to the

efficiency of the filtration of municipal water supplies, has long been

unsatisfactory. The Bureau has requested samples of standard turbidity from water laboratories representing the State and city boards

of health. These have been received and are now being intercompared. The results will show the variation in the standard now in

use, and will give the relation between the present and the proposed

new standard. The Bureau will then be in a position to furnish a uniform standard of turbidity to the entire country.

Interference Methods for Measuring Thermal Expansion.

The apparatus, using the interference of light waves to measure

thermal expansion, has been thoroughly tested and found to work

satisfactorily. The expansion coefficients of several different makes

of chemical glassware have been determined, the purjDose being to

find the relation of thermal expansion to breakage on sudden change

of temjDerature.

The investigation of a new method for measuring the expansion of

very small samples has been completed. The advantages of this

method consist (1) of the smallness of the sample required; (2) the

elimination of the difficulty of obtaining the interference fringe data,

it not being necessary to count the passage of fringes during the

temperature change nor to make measurernents on fringes of more

than one wave length; and (3) the very troublesome correction for

change in the refractive index of air with temperature is eliminated.

The results of this study were communicated to the Philosophical

Society of Washington, and it is expected that a full description of

this method will appear later as a scientific paper of the Bvireau.

A method for determining the difference in expansion of these

samples from the same specimen simultaneously has been devised and

tested. It has been successfully applied in testing the relative expansions of various parts of rails in connection with the Bureau's investigation of the cause of failure of rails. This investigation is being

continued.

Investigation of the Performance of American-Made Photographic

and Projection Lenses.

An investigation was started on the relative performance of American-made photographic and projection lenses. European-made

lenses have been very popular in this country, as they were supposed

to be of the highest type of perfection. Very little is known of

American-made lenses, as no comparative data have ever been piiblished. A survey of American lenses would show where they could

be used to best advantage. Several lenses were examined and measured, but it was considered impracticable to continue this work for

the present, due to the difficulties vmder which the lenses have to be

manufactured and the scarcity of good raw material.

Telephoto Lenses and Distance Photography.

Several types of lenses and cameras are being investigated in con- nection with their proposed utilization for photographing at great
92 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

distances. Certain data, such as the appearance of the rocks on an

inaccessible mountain peak, become possible only when they can be

photographed from an accessible point. One type of camera was

deA'eloped which gave very good results in the laboratory. It will

be further tried out under actual working, conditions. Other types

of lenses show very good promise and will be given further trial.

Development of Optical Systems.

The constants of some telescopes for use by the Navy Department

were measured, and further work will be carried on to adapt the

design to American-made optical glass. The different tj'^pes of glass

required for the Navy were reduced to four well-defined types. The

standardization of the types of glasses used and of the types of telescopes will make possible production in the required quantity in the

shortest time.

Testing of Optical Systems.

The Bureau has received a great many binoculars and telescopic

instruments, both from the Navy and Army and from manufacturers

with a view to improving the output. Especially has the amount of

light let through been interesting. The early part of the European

war forced the manufacturers to use inferior opaque glasses, thus

producing binoculars with very low light transmission. Many tests were perfox-med, and during the last year an improvement of over 50

per cent has been noticed. The field, resolving power, and general

definition were well up to the standard.

Refractive Indices.

The amount which a ray of light is deviated in passing into a piece

of glass is known as the refractive index. The refractive index

changes with the wave length of light used, this change being known

as the dispersion. These two constants determine the type of optical

glass and the uses to which it is put. The manufacture of glass in

this country has made measurements of this type very imjDortant,

and a great many tests have been carried out for opticians and optical manufacturers. These constants are also very important in

those industries where oils and liquids are used, where it is necessary

to test the purity of these substances. Several tests were performed

on oils at the request of manufacturing companies.

Information Furnished on Optical Systems and Optical Glass,

A great many inquiries have been received and answered regarding

the adaptability and the practicability of optical instruments. Much

time has been spent with the Navy Department in drawing up suitable specifications for various kinds of optical glass and optical

instruments.

Many samples of optical glass have been tested for strain, strise,

refractive index, and transparency, to obtain an idea of the progress

being made in their manufacture. The results are very gratifying.

The methods of testing optical glass for strain and striae and the

method for measuring the transparency of glass wex*e requested by

several manufacturers, so that they could be in a position to gauge

their own progress. These methods are being fully developed in
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 93

order to make them commercially more practicable, and will be published in a circular as soon as completed.

Optical Constants of Chemical Glassware.

In connection with the determination of the types of glassware in

this country for chemical purposes, the strain has already been determined. An attempt was made to correlate the heat resistivity and

physical strength with the strain and the refractive index of the

glass, but it has been found very difficult, as composition and expansion of the glass and the thickness of the vessel play a very important part.

Radiometry.

Various investigations have been continued in the general subject

of radiometry, including the improvement of instruments for measuring radiant energy.

The application of the photoelectric cell as a precision instrument

in radiometry was investigated. Several potassium photoelectric

cells, made by Kunz, were compared with a bismuth-silver thermopile

by determining the transmission of colored glasses in the blue and

violet. This type of radiometer is not so easily affected by thermal

disturbances as is a thermopile, and is therefore well adapted for cer- tain special investigations.

A high resistance iron-clad Thomson galvanometer was constructed

to replace the electrometer in photoelectric work. The device is from

35 to 40 times as sensitive as a low resistance galvanometer and a sensitivity of i—lX^O'^^ ampere is easily attained on a three to four

seconds swing. This galvanometer combined with a photoelectric

cell is especially adapted for transmission and reflection measure- ments in the part of the spectrum extending from the blue into the

ultra-violet.

A determination of the energy distribution in the visible spectrum

of several gas-filled tungsten lamps, to be used as color standards,

required considerable investigational work.

Constants of Radiation of a Uniformly Heated Inclosure.

During the past year several investigations have been made of subsidiary problems connected with a further determination of the constants of radiation of a black body. An absolute thermopile for

measuring the constant of total radiation in a vacuum was con- structed and tested, as well as a vacuum-linear thermopile. The circle of the spectro-radiometer and its reading microscopes were modified and calibrated. New tungsten lamps were prepared for the

optical pyrometer mentioned in the report of last year.

Measurements were made to determine the absorption of a 50-centimeter column of dry air, and of air containing water vapor, to determine whether there is a correction to the constant of total radiation

data previously published. The results obtained indicate no correc- tion when using air which is free from water va]3or. The corrections

to the observed data for losses by reflection from the radiometer

receiver were recomputed and the value of the coefficient of total

radiation was foimd to be the same as previously reported. These

data are of importance in determining the scale of temperature at
94 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

high temperatures, and they are of interest in view of their intimate

relation with the fundamental physical constants.

Visibility of Radiation of the Average Eye.

It is important to know how the eye responds to lights of different

colors but of the same energy value. During the past year the investigation of the relative sensibility of the average eye to light of

different colors was completed. The visibility of radiation of 130

subjects was determined, and various applications were made of these

data to problems in radiometry.

A solution of salts was prepared which has a transmission curve

coinciding very closely with the visibility curve of the average eye.

Using a cell containing this solution, interposed between a thermopile

and a source of light, further tests were made of this combination as a physical photometer. Using these visibility data, computation

shows that tlae eye is so sensitive that the minimum perceptible light

is probably less than one billionth erg.

Mechanical Equivalent of Light.

A mathematical equation was obtained of the above-mentioned

visibility curve of the average eye. This equation was combined with

Planck's equation of spectral radiation of a black body. Using the

radiation constants of a black body and its brightness at various temperatures, it was possible to obtain the luminous equivalent of radiation or the so-called mechanical equivalent of light.

Independent checks of this constant were obtained by measure- ments upon an incandescent lamp of known candlepower, using the

physical photometer mentioned in the preceding section. The data

obtained by various methods indicate that the mechanical equivalent

of light is of the order of 1 lumen=0.0016 watt of luminous flux of

maximum visibility, or 1 watt=49 candles.

These data are of use in various physical problems and will have

an important practical application should the time arrive when

" light " is purchased as radiant ]3ower, just as electrical energy is

purchased at the present day.

Emissive Properties of Tungsten.

The emissive properties of tungsten were investigated by two methods. One investigation consisted in the determination of the selective

reflection of plane, highly polished mirrors of timgsten in the visible

and in the infra-red spectrum. A depression was found at 0.8 in the

reflectivity curve, which is the cause of a marked selective emission

band found in incandescent tungsten.

The second investigation was on the selective emission of straight

and helical filaments of tungsten, in which it was shown that the

increased brightness within the helix is due almost entirely to multiple reflection. The most important deduction is that the radiation

from within the helix is not sufficiently close to that of a uniformly

heated inclosure to be used in the calibration of pyrometers.

Glasses for Protecting the Eyes from Injurious Radiations.

Attention has been called in previous reports to the importance of

this subject, and during the past year data were published on the

protective properties of typical glasses.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 95

It will no doubt be understood that radiometry is the logical basis

upon which to specify what constitutes ample protection from injurious radiations, whether ultra-violet or infra-red. At present information is quite lacking concerning the energy density and time

of exposure necessary to produce injurious effects upon the eye.

Photoelectric Properties of Various Substances.

Conditions have arisen which make it desirable to determine the

photoelectric sensitivity of substances in different parts of the spectrum, the energy measurements being made with a thermopile, which

is a nonselective radiometer. Such an investigation is in progress

and the results seem very promising.

Information Furnished on Radiometric Subjects.

In addition to experimental work, considerable information has

been given in compliance with specific requests for information on

radiometric matters, such, for example, as the radiative properties

of materials suitable for covering radiators ; the reflective properties

of metals ; Patent Office inquiries ; standard sources of light ; the effect

of the heat of the moon upon plant life; thermal-radiodynamic signaling devices ; selenium cells ; the design of greenhouses to be maintained at a uniform temperature ; and the application of radiometric

methods to physiological and psychological problems.

Publications on Radiometry.

During the past year the following papers on radiometry were

published: Technologic Paper No. 93, Glasses for Protecting the

Eyes from Injurious Radiations ; Scientific Paper No. 300, Emission

of Straight and Helical Filaments of Tungsten; Scientific Paper

No. 303, Relative Sensibility of the Average Eye to Light of Different Colors and Some Practical Applications to Radiation Problems;

Scientific Paper No. 305, Luminous Radiation from a Black Body

and the Mechanical Equivalent of Light; and Scientific Paper No.

308, Reflecting Power of Tungsten and Stellite. Experimental data

were furnished for Scientific Paper No. 304, Calculation of the Constants of Planck's Radiation Equation : An Extension of the Theory

of Least Squares.

5. CHEMISTRY.

[Chemical composition and purity of material, chemical properties and constants, including researches upon methods of analysis, specifications for technical materials, and_ preparation of pure materials for standardization work for the Government and for industrial and scientific laboratories.]

Rapid Electrolytic Determination of Carbon in Steel,

The method developed for the rapid estimation of carbon in steel,

referred to in the report for last year, has been improved and the

results will soon be described in a forthcoming paper. The method is

extremely rapid and seems to be well adapted for control Avork in

steel plants; at the same time its accuracy is high. The carbon

dioxide formed by burning the steel in oxygen is collected in a solution of barium hydroxide of known strengtli and conductivity. The

resultant decrease in conductivity of the solution is a measure of the

carbon burned.
96 REPORT OF DIRECTOR OF BUREAU OF STAITDARDS.

Nitrogen in Steel.

A direct method for determining gaseous nitrogen in steel has been

devised and experimentally tested. The nitrogen (which may be

admixed with any other gas or vapor that is free from nitrogen) is

brought in contact with vapor of metallic calcium in a suitable apparatus and under reduced pressure. The nitrogen is immediately

absorbed by the calcium as nitride. When this is dissolved in hydrochloric acid ammonium chloride is formed, and in this the nitrogen

is determined by the usual methods. Experimental tests on s^^n- thetic mixtures were vei-y satisfactory.

The Goeren's Method for Determining the Gas Content of Steels.

The Goeren's method for determining the gas content of steels

depends upon melting the steel mixed with metals which lower its

melting point to a convenient working temperature, in an evacuated

tube, and analyzing the gases evolved.

Much progress has been made in constructing the complicated

apparatus required by this method, and when assembled the method

will be given a thorough trial.

Determination of Gases in Steel by the Goutal Method.

In pursuance of a plan to investigate sources of error in present

methods for determining gases in steel and to originate new methods,

if needed, the Goutal method was made the subject of study. This

method consists in dissolving the steel in a solution of copper-potassium chloride in an apparatus which permits the gases given off during solution to be absorbed. Contrary to Goutal's conclusions, it has been found that the gas content thus obtained is an entirely

fictitious one so far as concerns carbon monoxide and carbon dioxide,

since these gases are generated by the oxidizing action of the cupric

salt on the carbides present and there is, therefore, no relation between the observed percentage of these gases and the amounts actiaally present in the metal. A paper on this subject is in course of

preparation.

Determination of Oxygen in Steel.

A study of the Ledebur method for determining oxygen in steel

has been completed and a paper on the subject is in preparation.

This paper will contain results of tests for oxygen in a number of

steels and irons by the Ledebur method, with special precautions to

aA^oid all known or suspected sources of error. Oxygen Content of Steels Deoxidizable in Various Ways.

The improved Ledebur method referred to in the preceding sec- tion is being used to examine for ox3^gen content several heats of

steel made (1) by ordinary commercial methods and (2) by variations of commercial practice with regard to deoxidation methods.

The results of this investigation will be embodied in a paper.

Ladle Ingot Test Investigation.

The work begun a year ago on ladle ingots has been continued and

four sets of ladle test ingots made in molds typical of American

practice have been cast under uniform conditions of customary prac-
EEPOBT OF DIBECTOR OF BUREAU OF STANDARDS. 97

tice at two steel plants. Two sets were of " rising " steel and two

of "nonrising" steel. To the former aluminum was added in the

mold at the time of pouring and the effect was to produce physically

sound steel. All these ingots are being examined metallographically

and later will be tested chemically for segregation.

Preparation o£ Iron-Carbon Alloys.

The general problems relating to the preparation of alloys of iron

and carbon and the development of new alloy steels are discussed

in the report of the metallurgical division. These problems involve

much cooperation in research and testing on the part of the chemistry

division.

Platinum Investigation.

It has been impossible to take up the extended research upon the

chemical and physical properties of the platinum metals which was

referred to in the report of last year, but provision has been made for

beginning it during the coming year unless the exigencies of the war

situation should make it expedient to postpone the work still further.

Several substitutes to replace platinum ware for chemical and

physical uses have been proposed, and one of these has been submitted at the Bureau to a series of tests which show it to compare

very favorably with platinum for most chemical uses. This is an

alloy of 80 parts gold and 20 parts palladium. Alloys of quite

•different composition which have been submitted for test or soon

will be submitted may prove suitable for use in other ways but are not likely to find extended use by chemists.

The New York assay office, continuing its cooperation of the past

year, has made for the Bureau over 20 crucibles and a few miscellaneous articles of platinum which have given satisfaction. It is hoped that the Government laboratories generally will soon be able

to draw their supplies from this source.

Variation of Commercial Gases from Boyle's Law.

The variation of natural gas from Boyle's law is of sufficient importance to introduce important differences in the apparent volume

of gases measured at high pressure, as, for example, in connection

with orifice meters, proportional meters, and other commercial metering equipment. At the suggestion of the Bureau, a means for taking

account of this variation has been tried out in practice by certain

natural-gas engineers and considerable success is anticipated in the

further application of this method for correcting for the variation in

compressibility of the gas from the theoretical values.

Specific Gravity of Gases.

The work reported a 3^ear ago on the specific gravity of gases has

been continued and the specific gravity balance devised at the Bureau

has been given field trials and certain improvements indicated as desirable have been made. The perfected apparatus has been constructed for use by a considerable number of natural-gas companies^

and these are employing it regularly in their laboratories. Arrangements have been made for marketing this balance by one of the

makers of physical-chemical apparatus, and the number of requests

18533—17 7
98 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

for information on the subject indicates that wide application of

the instrument is to be expected. The full investigation and its re- sults are reported in Technologic Paper No. 89, A Specific Gravity

Balance for Gases.

The closely related work on the effusion method for specific gravity determination has also been carried to a very successful conclusion and a report on this work has been made in Technologic Paper

No. 9-1, Effusion Method for Gas Density. The theoretical aspects of

this work have been developed in cooperation with one of the other

divisions of the Bureau and a paper covering the conclusions is practically completed. This theoretical consideration of the subject has

demonstrated the relation between the various properties of a gas

and its apparent specific gravity as determined by the effusion

method with apparatus of different characteristics. A most interesting theoretical development is that the effusion phenomenon is

one of stream-line flow and not a molecular phenomenon as ordinarily

believed.

Preparation and Properties of Hydrogen.

Additional determinations of the heat of combustion of pure

hydrogen have been made, but until the heat division of the Bureau

can give more time to this subject, little progress can be made in the

pi-epa ration and the study of the properties of pure gases. It is inadvisable to begin work on carbon monoxide and carbon dioxide

imtil the work on hydrogen has progressed further.

Balloon Gas Investigation.

At the request of the Signal Corps and of the Navy Department the

Bureau is investigating methods for the generation of hydrogen,,

making certain tests of the materials from which this gas will be

generated and cooperating in the drafting of instructions for the

personnel which will operate and maintain the field and service

equipment. This work will include study of hydrogen generation

and compression and the filling of balloons, both to prevent explosions and to maintain the highest operating efficiency feasible under

service conditions.

Combustion Gas Detectors.

An important research, in cooperation with one of the other divisions of the Bureau, on detectors for combustible gases has led to

results of importance. Four types of detectors have been perfected

which are suitable for various locations and uses. The type recom- mended to the Navy Department for use on submarines has proven

so satisfactory in tests at the Bureau and the Brooklyn Navy Yard

that it has been adopted for use on certain vessels. A report on this

subject has been requested by and made to the naval authorities of

Great Britain and Italy on the types of detectors specially recommended for naval use. The question of the application of these devices for the detection

and determination of carbon monoxide in the air has also been considered, but it is doubtful if the practical apparatus for use outside

the laboratory can be made sufficiently sensitive to detect less than

0,1 per cent of carbon monoxide, which is the maximum quantity
KEPOKT OF DIRECTOR OF BUREAU OF STANDARDS. 99

that is considered safe to permit in the atmosphere where persons

are working.

Chemical Work on Balloon Fabrics.

At the reqiiest of certain branches of the Navy and War Departments, the Bureau undertook to make tests on the permeability of

fabrics for balloon construction to hydrogen and other balloon gases.

1'his work indicated at once the need for more precise information

than was available as to methods of permeability determination, the

t-'ignificance of these tests, and for other work on balloon fabrics. As

nn outgrowth of this testing the Bureau has undertaken an extended

investigation of testing methods, life test on "fabrics, and the improvement of fabrics in order to increase their life or to improve

them in certain characteristics.

As a result of this work there has been developed a tentative specification for characterization of fabrics, covering permeability,

Aveight, and strength, and including methods for performance of

tests to determine compliance with these specifications. These will

supersede other specifications that contained certain requirements

which seemed impossible of interpretation or were meaningless and

will probably make possible more satisfactory relations between the

Government and the makers of these fabrics. The tests on permeability are almost completed, so that it is now possible to define

with considerable accuracy the relation between tests under one set of conditions and those under another set and to eliminate the uncertai^^ty in the significance of these test results.

The exposure test planned to determine the life of fabrics includes

heating, exposure to light and radiation, exposure to weather, and

comparison with actual service tests of the fabric in aircraft. The

lest involves experiments on glues and protective coatings for both

balloons and other aircraft. The cooperation of manufacturers, the

Signal Corps of the Army, and the Navy Department in this work

will make the results of wide interest and value.

Chemical Work on Refrigeration Problems.

The work on refrigeration problems has made satisfactory progress

and will be continued the coming year unless interrupted by more

urgent demands in other directions. This work has involved the

jireparation and testing of pure materials and the study of gas formation in ammonia refrigeration systems. Specifications for an- hydrous liquid ammonia have been prepared, and a report has been

made on methods of testing and the composition of commercial

.samples.

Chemical Work on the Standard Cell.

The standard-cell work has developed in such a way that it has

been possible to furnish practical results in the construction of standard cells, which are necessary and very difficult to obtain in the

market.

A series of Clark (zinc) cells was prepared in August, 1916, which

show great constancy. They were set up with the special object of

avoiding gas formation and the cracking of the amalgam limb. A

]->aper on the subject is now in preparation.
100 EEPOET OF DIEECTOR OF BUEEAU OF STANDAKDS.

A considerable number of unsaturated cadmium cells have been

prepared for the purpose of meeting the public demand, in view of

the inability of manufacturers to supply them under present conditions. Such cells are quite necessai-y in work depending on hightemperature measurements and are essential in the prosecution of

certain phases of war work. The results accumulated will form the

basis for several papers.

Electrotyping and Electroplating Investigation.

Largely as a result of the work conducted by the Bureau upon the

use of American ozokerite, there has been placed upon the market

molding wax which appears to be satisfactory for electrotyping.

This has not yet, however, come into extensive use, owing in part to

the difficulty of adapting any one mixture to the variable conditions

existing in different establishments.

During the year some progress has been made in cooperation with

the electrical division upon the study of the conductivity of copper

solutions. The results indicate, however, that there is a need for an extended and fundamental investigation of the methods of determining the conductivity of such solutions.

It is hoped to make more rapid progress upon some of the specific

electrotyping problems during the next year through the cooperation

of the international Association of Electrotypers, who have agreed

to pay the salary and traveling expenses of a chemist to work upon

their problems at and under the direction of the Bureau.

No definite progress has been made in the general study of electroplating problems. Numerous requests for information and for

tests have come from the public and from Government departments.

One of the most pressing needs in this industry appears to be the

formulation of specifications for various kinds of plating, based upon

chemical and metallographic examination, and possibly upon ac- celerated corrosion tests, such as, for example, the " salt spray test." In most cases, however, intelligent formulation of such specifications will involve a more or less detailed study in plant and laboratory of the conditions affecting the properties of the deposits.

In order to make such investigations at the Bureau on a semicommercial scale, a plating laboratory is now being installed, provided with a 3-lcilowatt generator and a number of small stoneware

tanks. As the Avork progresses it will be necessary to increase this

equipment to include apparatus for cleaning the articles and for

polishing the deposits, etc. With the present staff assigned to this work, it will probably be

possible to study the above and any other plating problems of military importance likely to be referred to this Bureau. Rapid progress

upon the more general and fundamental problems of electroplating

will, however, require additional assistance.

Renewal of Work on Various Analytical Problems.

Arrangements have been made to renew the work on various

analytical problems undertaken some time ago but discontinued be- cause of press of work in other fields. Among such problems are the study of volumetric standards, the analysis of phosphate rock,

and the s+it^^ of the mialitv of reagents. The latter subject is now
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 101

SO urgent that the American Chemical Society has taken steps to secure the active assistance of the Bureau in this work. It is recognized that with the limited force available under present abnormal

conditions it will not be possible to make very rapid progress on these

problems.

Paint and Varnish Investigations.

A number of investigations on paints and varnishes have been con- ducted during the past year in cooperation with a committee of the

American Society for Testing Materials, some of which are the

practical testing of varnish; a study of unusual drying oils (Lumbang and Perilla) ; a determination of foots in linseed oil; a determination of the flash points of paint thinners; specifications for paint

pigments ; the preparation of standard methods of analysis of paint

materials; and others.

A large number of service tests of paint and varnish was made

for the federal General Supply Committee.

A convenient color scale of varnishes has been devised by making

use of solutions in strong sulphuric acid of varying amounts of

potassium bichromate.

A circular of information on paint and varnish, giving descriptions of raw materials, methods of manufacture, and methods of

application of paint and varnish has been prepared for publication.

A satisfactory formula has been evolved for a paint that should

be extremely white, dry flat, and adhere to cement, wood, or eloth

surfaces.

An important line of work that should be taken up is that of field

tests. This comprises the systematic study of various paint materials by inspections of painting operations on large scales in vari- ous localities, and of occasional check panels of similar materials

made at the Bureau.

Nonferrous Alloys and Coated Materials.

The major part of the work on nonferrous alloys and coated materials has been confined to routine testing of material for the

Panama Canal and the Supervising Architect of the Treasury

Department.

More or less research was involved in the following items:

Study of the efficiency of the Parker Eust Proof Process to prevent

corrosion of iron and steel ; work on metal lathing in connection with

the Bureau's stucco investigation; testing of fusible boiler plugs;

examination of a failed fuse box cover from a locomotive in the

Canal Zone: analysis of copper for an industrial concern; analysis

of copper cable for the Argentine Naval Commission, and a determination of the zinc coating on galvanized wires. Of three methods

used in connection with the last problem, namely, the antimony-hydrochloric acid method, the lead acetate method, and stripping in

dilute sulphuric acid with correction for iron dissolved, it appears

that the second and third yield results that are in fairh^ close agreement, while the first gives results which are too high.

A comparative corrosion test on brass and monel metal confirms

commercial experience that the monel metal ordinarily gives better

satisfaction.
102 EEPOET OP DIRECTOB OF BUREAU OF STANDARDS.

At the request of the "War Department, tests were made to determine the comparative durability of certain sherardized and electrogalvanized steel castings. Samples prepared by four companies were

tested by the " salt spray " method. The tests showed the electrogalvanized samples to be superior to those that were sherardized.

Bituminous Materials.

The work on bituminous materials has developed materially. The

number of samples has increased and those of new type are being submitted which require the development of special methods of testing.

About 400 samples of the important brands of roofing and waterproofing felts from about 40 manufacturers have been received and

filed for reference, both as an aid in identifying these materials and

to enable the Bureau to keep in touch with what is to be foimd on

the market. The samples will also prove of value in passing on prepared roofings to be used on the various cantonment buildings

recently constructed or under construction. The office of the Quartermaster General, United States Army, requests that the Bureau

should be familiar with all of these materials. After these roofings

have been in place a year or two they will be inspected, and it is believed that much valuable information will be gained.

Samples of authentic tars from various sources have been obtained from which it is proposed to distill creosote oils. These oils

will then be studied as authentic oils to serve in grading oils that

are i-eceived for test. It is also planned to ascertain whether or not

the Forest Service method of distillation produces an undue amount

of " cracking " of the oil. Arrangements have been made to study a number of samples of

" ship's insulating felt," known commercially as " Irish felt," with

the object of developing a satisfactory specification.

The melting point of asphalt has been the object of some study

and the ring and ball method of determining it. since adopted as standard by the American Society for Testing Materials, has been

submitted for the cube method in an air bath.

A representative of the Bureau visited the asphalt lakes in Trinidad and those in Bermudez State, Venezuela, and gathered much

information that will be of value in testing the asphalts from these

sources. The same representative returned by way of the Canal

Zone, where materials in service which the Bureau had tes*:ed were

inspected. The information so gained is of great value in determining the fitness of materials for this climate and for the uses to

which thej are put.

Chemical Work on Cement.

In addition to the regular routine work on cements, limes, and

plasters, much work has been done in cooperation with the cement

division in investigations of the chemical changes occurring in mortar and concrete when exposed to sea water, " alkali " waters, and

under abnormal conditions. Further cooperative work is planned

on the problem of drain tile disintegration in other than alkali"

waters. A number of concrete floor-hardeners were examined for

the cement division preliminary to a more extended study of the use and utility of such materials.
EEPORT OF DIEECTOK OF BUREAU OF STANDARDS. 103

Chemical Tests of Lubricants.

The demand for tests of lubricants has been so very great during

the past 3'^ear that it has been impossible to take up tlie contemplatetl

study of certain problems along this lino. Cooperative work with

the American Society for Testing Materials has continued in this

direction.

Chemical Work on Leather.

For some time physical tests of leather have been made at the

Bureau and the need for chemical control has become eviilent. The

chemical division is now engaged on this work and, in addition, the

National Tanners Association is cooperating witli the Bureau on

the subject. A rapid and sufficiently accurate method for determining the specific gravity of leather has already been devised.

Chemical Analysis of Rubber.

The method devised at the Bureau, referred to in a previous re- port, for the direct determination of rubber by combustion of the

nitrosite involved many difficulties, even when compounds containing

new rubber were analyzed. These difficulties have been overcome

and it is now possible to obtain correct results even when reclaimed

rubber and lampblack are mixed Avith new rubber. A paper describing the method is now in preparation.

The factors which influence the determination of rubber and an

accelerated aging test are under investigation and have yielded preliminary results of promise.

The Bureau has assisted in the work of tlie Joint Rubber Insulation Committee and its method for the determination of total sulphur

in rubber has been adopted by the committee as an alternative procedure.

Chemical Work on Paper.

Hydrocellulose, in powdered form, prepared from waste parchment paper, has been purchased and used as a filler instead of the

clay and other mineral matter commonly used. Samples of paper

made at the Bureau were tested in a wet plate press and gave excellent results.

A form of colloidal cellulose, not described in the literature, has

been prepared. It is hoped to use it as a sizing for paper.

Work has been started, and is still in progress, on paper containers

to be usecl as substitutes for tin cans. A bulletin on this subject has

been issued jointly "with the Bureau of Foreign and Domestic

Commerce.

There has been considerable demand for Technologic Paper Xo. 87,

describing the method for recovering pulp and paraffin from scrap

paraffin paper.

An investigation of the precipitation of rosin sizing, after considerable progress liad been made, had to be dropped temporarily

because of more urgent work.

"Tests of Chemical Glassware and Procelain.

Comparative tests of a number of brands of domestic and foreign

glassware and porcelain for chemical use have been made and the

results will soon be published.
104 KEPORT OF DIRECTOB. OP BUREAU OF STANDARDS.

Standard Analyzed Samples.

Another great increase is shown in the demand for the Bureau's

standard samples. The number called for during the fiscal year 1917

\yas 3,536, as against 2,697 in 1916, and 1,826 in 1915. The distribution was as follows: Irons and steels, 2,867; brass, 54; ores, 229;

sodium oxalate, 139; naphthalene, 120; benzoic acid, 30; sucrose, 76;

dextrose, 6 ; metals for melting points, 13 ; cement for testing sieves,

2. Six samples under the last two items are new and have been

issiied only during a part of the year. An Alabama iron sample is

also new. Three steel samples have been renewed.

The rapid groAvth in the demand for the samples makes it increasingly difficult with the means at command, to replenish exhausted

stock and to add to the list of samples. Hence, it happened more

than once that considerable time intervened between the exhaustion

and renewal of a sample. A special fund should be available for the

purchase and preparation of materials, apparatus, and appliances.

Chemical Testing.

Somewhat over 9,000 tests were made in the chemical laboratories

of the Bureau during the year. They involved the following materials: Ferrous metals (irons and steels), 319; coated metals, 832;

nonferrous metals and alloys, 912; mateiial from elcctrotyping baths,.

27; cement materials. 1,205; coal tars, asphalts, and saturated felts,

984; burlap and building paper, 53; linseed oil, turpentine and

driers, 562 ; varnish and shellac, 495 ; red lead, white lead, and putty,

371 ; paint materials, 407 ; greases, 109 ; soaps, 203 ; nondrying oils and

metal polishes, 130; lubricating oils, 431; inks and ink materials,

368; flax packing, 17; asbestos, 60; paper, 761; rubber, 281; sealing

wax, 11: Avools and textile materials, 121; miscellaneous, 382;

total, 9,041.

The above tests were made for about 80 Government bureaus and

establishments, including, practicalh^, all the executive departments,

and for States, municipalities, and private parties, as follows: Agriculture, 19; Commerce, 1,380: Interior. 152; Labor, 20; Navy, 293;

Post Office, 346; Treasury, 2,462; War, 350; Panama Canal, 2,574;

Government Printing Office, 680; General Supply Committee, 423;

other Federal institutions, committees, and commissions, 65; State,

municipal and other institutions and committees, 150; and private

parties, 126.

Miscellaneous Chemical Tests and Investigations.

Many miscellaneous tests of interest have been made upon a great

variety of subjects and materials, in part as follows: " Glasso," a material intended to prevent clouding of wind shields and goggles by

rain or mist; Columbian Spirits, recommended as superior to ethyl

alcohol for analytical purposes, and found not to be as suitable

for soap analysis as ethyl alcohol ; " Safetch," a material said to be

excellent for use on aluminum plates used in map printing; and

similar preparations.

Cherriical Publications.

The following papers, circulars, and addresses emanating from the

chemistry division have been published during the year or are nearly ready for publication: Technologic Paper No. 87, Recovery
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 105

of Paraffin and Paper Stock from Waste Paraffin Paper; Technologic

Paper No. 89, A Specific Gravity Balance for Gases; Technologic

Paper No. 88, Studies on Paper Pulp; Technologic Paper No. 94,

Effusion Method for Gas Density; "Our analytical chemistry and

its future" (Chandler Foundation lecture, Columbia University);

"Determination of gas density," to be published in a technical journal ; " Calibration of the gas interferometer," to be published in a

technical journal; "Gas investigations of the National Bureau of

Standards"; proceedings of the Sixteenth Annual Convention of the

Wisconsin Gas Association, March 13, 1917 ; " Reducing matter extractable from filter paper," Journal of the American Chemical Society, volume 39, page 928, 1917 ; Technologic Paper No. 98, The Effects

of Heat on Celluloid and Similar Materials; "Composition and

testing of commercial liquid ammonia," Journal of the Society of

Refrigerating Engineers, volume 3, page 30, March, 1917; Circular

No. 25 (revised). Standard Samples—General Information; Circular No. 62, Specifications for and Methods of Testing Soaps; and

Circular No. 69, Paint and Varnish Materials.

New Chemistry Building.

Delays due to certain differences with the contractor for construction and inability to obtain certain materials for equipment

and labor for installation made it impossible to occupy the new

chemistry building early in 1917, as had been expected. The transfer

of men and working equipment began in June and will be completed,

it is hoped, before the end of July. The occupation is progressing

under difficulties, for not all of the necessary piping and fittings are in place even now, but the transfer is rendered necessary by tha

pressing demands for the space now occupied by the chemistry forca

in four other buildings.

The additional emergency appropriation of $35,000 recently provided will probably permit the whole building to be fully equipped.

However, the equipment installed thus far provides no more than

for the present force of chemists, which is being rapidly increased

to meet the needs of the war situation.

6. ENGINEERING RESEARCH AND TESTING.

[Operative efficiency of mechanical appliances, accuracy of engineering instruments, conditions affecting their effect i/e use, e. g., structure and design as related to durability and

efficiency; methods of standardization and test, standards of performance, and funda- mental researches on the scientific principles involved in speedometers, pressure gauges, water-current meters, anemometers, tachometers, gasoline and other motors, propellers,

and other airplane parts and materials, etc.]

Water-Current Meter Rating Stations.

One of the most important engineering services rendered by the

Bureau is the furnishing of accurate calibration of current meters.

The^e instruments are used by civil and hydraulic engineers in the

measurement of the velocity of flowing water in rivers, irrigation

canals, and other open channels, to secure data for the computation

of the quantity of water discharged through such channels in a given time, data necessary in the development of the water re- sources of the country in power development, irrigation, flood prevention, and similar projects. To secure accuracy in these measurements, the instruments must be calibrated from time to time. A
108 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

body of still water mnst be available for this purpose, together with

equipment for towing the instrument through the water at dilFerent

uniform speeds and for accurately recording the observations.

Adequate installations of this character are costly and ai'e necessarily confined almost entirely to Government stations and large

university laboratories, which are not always available for this

purpose. In the new rating station designed and constructed by the

Bureau especially for this work, exceptional facilities are afforded

. for the calibration and study of these instruments. Since the entire

flume was housed in a year ago, the station is in continuous operation throughout the year. While a majority of the ratings made

are for the different engineering bureaus of the Government, this

service is also performed for engineers in private practice, a rating curve and table being furnished for a nominal fee.

During the past fiscal year 277 current meter ratings were made.

Of this number 203 were for the Government departments and 74 for

engineers outside the Government service. The latter figure shows

an increase of about 80 per cent over the number for the previous

year. A number of special tests were also made, including tests of

six meters of a new type for an instrument manufacturer, a special

rating for the Canadian Geological Survey, and tests of meters for

research work by Government bureaus.

Different Forms of Cable Suspension for Current Meters.

In making measurements of current velocity in deep streams, the

current meter is suspended from a cable on a hanger, to which are also

attached weights of a standard form to keep the cable in an approximately vertical alignment. The number and size of weights used

vary for different conditions met in the field. At the request of the

United States Geological Survey, an investigation was conducted of

the deviations from the rating made with its standard form of cable

sui:)port, produced by each of several arrangements of weights commonly used in the field differing from the ordinary standard in the

size of weights and in their position on the usual strap hanger

relative to the meter.

Factors were obtained by means of which the standard rating table can be used without a special rating of the meter for each particular

case. The results of this investigation have been embodied in a circular issued to its field engineei's by the Geological Survey. This

investigation has been extended at the request of the Geological

Survey to obtain similar data for new equipment which has recently

been adopted for field use. Depth of Submersion of Current Meters,

An investigation has been in progress to determine the effect of the

depth of submersion on the rate of rotation of the small Price cur- rent meter. Tefts have been made for depths of from two-tenths of

a foot to 2 feet for velocities from one-half foot to feet per second.

This work has been practically completed. The results thus far

obtained indicate that for the same velocity the rotation of the meter

is in general increasingly retarded as the meter approaches the surface, but that this effect practically disappears at depths greater

than 1 foot.
EEPOKT OF DIRECTOR OF BUREAU OF STANDARDS. 107

Fire-Extinguisher Investigations and Tests.

A report has been made to the Steamboat-Inspection Service,

embodying the results of an examination and test of 75 different

makes of hand fire extinguisliers, in compliance with a request from

that Bureau. Included in these different makes were extinguishers

of the dry powder, soda and acid, and carbon tetrachloride types.

The various devices submitted have been classified and the limitations

and particular fields of service of each type have been outlined.

Each extinguisher was tested from the standpoint of safety and

reliability in operation and effectiveness as a first-aid fire appliance.

The Steamboat-Inspection Service has been furnished with data

for use as a basis for the future approval of devices of this character

used on vessels under its jurisdiction. As a result, a number of

extinguishers which do not embody the most modern practice in the

construction of these devices will not be included in the list of

approved extinguishers. It was found, for example, that a large

proportion of the small hand extinguishers which use extinguishing

fluids consisting principally of carbon tetrachloride were, owing to

their principle of operation or defects in their construction, unreliable and not suited for first-aid fire-extinguishing purposes.

The testing of extinguishers which have been submitted since the

first report was made and the retest of those which have been modified since the first tests and resubmitted is still in progress.

A more extended investigation of several types of fire extinguishers

with especial reference to their use on vessels has been planned

for the coming year.

Advice has also been furnished to other Government bureaus in

connection with the purchase of fire extinguishers.

Fire-Extinguishing Equipment for Wooden Submarine Chasers.

At the request of the Navy Department, the Bureau is investigating the subject of fire protection for the engine compartment of

wooden submarine chasers. The unusual conditions to be met on

board these small wooden vessels introduce a fire hazard requiring

special fire-extinguishing equipment of the most reliable and efficient

type. The problem is being studied in the light of all available data

on the subject and experiments are l^eing conducted to determine the

kind of fire-extinguishing equipment that is best suited for the

purpose.

Radiator Traps Used in Vacuum Heating Systems.

The testing of different makes of radiator return line valves, undertaken at the request of the Supervising Architect of the Treasury Del)artment, has been continued. These valves are used in vacuum heating systems. One of these devices is installed at the outlet of each

radiator in such a system, its function being to keep the radiator at

maximum temperature by the continuous removal of the air and

water of condensation, and to prevent the escape of uncondensed

steam into the return pipe. The economical and satisfactory operation of a heating system of this character is largely dependent on the

successful operation of these valves. Thousands of these devices are annually installed by the Treasury Department in public buildings

under its control. Samples of the greater number of the many
108 BEPOET OF DIKECTOB OF BUEEAU OF STANDAEDS.

valves of this character on the market have been tested. Data havebeen secured to determine a standard of performance for these devices and to enable the Government to select for its use the best valves

available.

High-Pressure Gauges.

While inexpensive apparatus for the checking of pressure gauges

for the measurement of the ordinary range of working pressures is available, the same is not true for pressures in excess of 1,00(>

pounds per square inch. During the past y^ar, the Bureau has been

called upon to calibrate 22 of these instruments designed for maximum pressures from 1,000 to 30,000 pounds per square inch. This

service was performed principally for gauge manufacturers and munition makers.

Sounding Tubes.

A series of tests were made for the Coast Survey to secure data for

establishing a scale for a new form of sounding tube being developed

by that service.

Spirits Meter,

A series of tests were made for the Internal Revenue Service of a new type of meter for the measurement of distilled spirits to determine its suitability for customs purposes.

Patrol Lanterns for the United States Coast Guard Service.

Tests were made for the Treasury Department to determine the

effect of high wind velocities on 12 different types of patrol lanterns

for use by the Coast Guard service. The tests were conducted in the

wind tunnel at the Washington Navy Yard, where it was possible to

subject the lanterns to wind velocities up to GO miles per hour.

Gasoline Intensifiers for Automobile Engines.

There are a number of materials on the market Imown as gasoline

intensifiers, for which the claim is made that when added in small

quantities to gasoline, an increased engine efficiency is secured. Six

of these materials were tested with a six-cylinder automobile engine

driving an electric absorption dynamometer, and a sample of gasoline alleged to be treated by a secret electrochemical process was

tested in the same way. The apparatus used was very sensitive and

capable of indicating small differences in power developed, but in

no case was there any noticeable increase in power or efficiency of

the engine when using the treated gasoline as compared with its

performance when using straight gasoline under the same operating

conditions.

Miscellaneous Tests of Instruments and Devices.

The routine tests of the engineering instrument section amounted

to 439, including 277 current meters, 22 high-pressure gauges. 64

pressure and vacuum gauges, 10 anemometers, and 66 miscellaneous

tests of instruments and devices, including tachometers, indicators,

air pumps, fire extinguishers, valves, paper testers, speedometers, etc.
KEPOET OF DIRECTOR OF BUREAU OF STANDARDS. 1C9

Cooperation with Scientific and Technical Societies.

The Bureau is cooperating with the National Fire Protection Association in developing standard requirements for the design and

installation of automatic sprinkler equipments, including " dry pipe " systems which are used in buildings when the temperature falls below the freezing point of water, and chemical sprinkler systems in

which liquids other than plain water are used as the extinguishing

agent and whose operation involves chemical reactions. The Bureau

is also cooperating with this association in establishing standard

specifications for pipes and pipe fittings, and in encouraging the

general adoption of the National Standard Fire Hose Couplings. A

revised edition of Circular No. 50, National Standard Hose Couplings and P'ittings for Public Fire Service, has been published and

there is evidence that municipal fire departments throughout the

country appreciate more fully than ever before the advantages of

fire-fighting equipment that is made interchangeable by the use of

standard connections.

Investigations Relating to Mechanical Appliances.

The investigations summarized under the following topics ai'e illustrative of a general type relating to mechanical appliances,

which are now carried out in several divisions of the Bureau, but

which will probably be combined into a new section of work relating

to mechanical appliances.

Spark-Plug Investigations.

Work has been done in cooperation with the electrical division and

witli the Pittsburgh laboratories of the Bureau in an investigation

of the causes of failure of ignition spark plugs in aeronautic engines,

with a view to remedying the difficulties. > Study of the behavior of many different makes of spark plugs,

both by laboratory experiments and service tests in an aeronautic

engine, have in part led to the preparation and adoption of accept- ance specifications by tlie Signal Corps. Tests are being made under

these specifications at the Bureau.

Test samples covering the whole range of possible porcelain composition, have been made up at Pittsburgh and are being tested for

their thermal and electrical behavior.

Arrangements have been made for the construction of spark plug

porcelain from the most promising of these compositions.

The temperature conditions to which spark plug porcelains are

subjected are being investigated by direct temperature measurements

in actual service with a view to devising means to meet satisfactorily

the conditions of high temperature and extreme temperature gradients which occur in aeronautic engines.

Aeronautic Radiator Investigations.

Work was started in May on an investigation of the relation between the geometric form of radiator cells and the cooling capacity

and head resistance of radiators under varying conditions of air

velocity and air pressure.

The program includes (1) a study of the fundamental laws of air

flow and heat transfer in cellular types of radiators by means of
110 EEPORT OP DIBECTOR OP BUREAU OP STANDARDS.

measnrements on all typical radiators now in use and other forms,

which are necessary to complete the series of practicable cell dimensions; (2) application of the results to tlie design of radiator cell

dimensions for maximum efliciency under various conclitions of

pressure and A'elocity; and (3) the establishment, if possible, of

designs for standard radiator units which can be readily built and

made interchangeable.

Equipment for this investigation, including a miniature wind

tunnel with a section 20 cm. square, built within a vacuum chamber,

has been substantially completed.

Installation of Aeronautic Engine Testing Laboratories.

In cooperation with the Signal Corps, the Bureau has built a dynamometer laboratory comprising equipment for the testing of

aeronautic engines up to 400 horsepower by means of an electrical

dynamometer. A separate installation for running service and

endurance tests of engines of practically any output is also under

Construction. In this latter installation, the engine is connected to a

test propeller to permit the taking of observations on the effectiveness

and durability of various devices and auxiliaries under service conditions. In both of these plants provisions were made for an accurate

study of engine perform{\nce, by the application of means for measuring power output, fuel input, speed, heat balances, etc. The object of this equipment is to provide a moans of studying

(he fundamental elements of the design and operation of aeronautic

engines with the immediate view of eliminating minor operation

difficulties and improving the construction of aeronautic power

plants, by furnishing reliable and accurate data.

One of the points to be determined by investigations of this

character is the max^'mum compression ratio that can be used with

safety in practice (this quantity determines the maximum power

output that is attainable with a given type and size of engine). This

work re(iuires an exact knowledge of the behavior of spark plugs

and ignition devices, as well as accurate measurements of the amoimt

of heat which must be taken care of by the raditor system. Another

important problem is the design of the radiator itself, an investigation of which is being made in cooperation with the National Advisory Committee for Aeronautics. The data hitherto available

regarding the heat-dissipating capacity of given radiator designs,

have been inadequate to give designers a sure basis upon Avhich to

work. Another is the problem of proper lubrication of the aero- nautic motor, both as to quantity, quality, operating characteristics,

and the oils to be used, including the temperature at which those

oils may be safely run. Still another is the effect of various fuels

and carburetion systems and of different designs of intake and

exhaust manifolds, all of which have a marked effect on the efficiency

and reliability of the aeronautic power plant.

Testing of Aeronautic Engines Under Conditions of Reduced Atmospheric Pressure.

In cooperation with the subcommittee on power plants of the

National Advisory Ccmmittee for Aeronautics, the Bureau is building a laboratory for the testing of aeronautic eng'nes under conditions of reduced atmospheric pressure, in order to determine among

other things, the effect of different grades of fuel with respect to the
REPOET OF DIEECTOR OF BUREAU OF STANDARDS. Ill

variations of atmospheric air pressure encountered under conditions

of actual flying. It may be that for high altitude service considerable

impi-ovement in power, climbing ability, and speed can be obtained

by the use of special fuels. The same laboratory will serve for test- ing out other methods and applicances, such as carburetion accessories, which have been pi-oposed for increasing the power output

at high altitudes. All of this work is of the utmost military

significance.

Liberty Engine.

Since the middle of June, the design work on the Liberty Engine,

which is to be produced on a large scale for uee on American-made

airplanes, has been temporarily quartered at the Bureau of Standards. All divisions of the Bureau have corperatcd to the fullest

extent in supplying technical information of every character and,,

where necessary, have conducted investigations to aid in the production of this motor.

7. METALLURGY.

[Thermal analysis and structure of metals, heat treatment and its effect upon the properties of metals and alloys including the researches involved in determining the causes

of metal failures, cooling and heating curves; the investigation of hardening, annealing,

tempering, cementation: the determination of critical ranges; and the preparation of- pure metals and alloys.]

Railway Materials Investigations.

The main outstanding rail problem from the standpoint of safety

in railroad practice is that of the prevention of transverse fissures.

The work of the past year has been directed in a number of ways

toward the determination of the nature and causes of such fissures.

A number of fissured rails furnished by various railway companies have been thoroughly studied and reported to the companies;

the inveftigation included physical, chemical, and metallographic

examination.

More work has b?en done on the distribution of temperature in

cooling rails of different sections, as throwing light upon the behavior of rails upon the hot beds.

A study has been made of the steel at various parts of the head

of fissured and normal rails in order to detect any evidences of lack

of thermal efiiiilibrinm (delayed transformation) which might

account for the brittleness usually associated with the steel at the

center of the head of fissured rails. This study included delermlnations of density, thermal analysis, and microscopic examination.

Determinations of the coefficients of thermal expansion at various

locations near a fissure has failed to indicate any significant

variations.

The investigation to date indicates that none of the ordinary

chai'acteri sties, including structure, expansion and chemical analysis

of fissured rails (except possibly the mechanical properties), exhibit

any variation from the normal condition in which cause might be

sought for the abnormal service behavior of the rail.

Chilled Car-Wheel Investigation.

Measurement has been made of the stresses developed in the plate

of the three standard master car builders Avheel (025, (57') and 72

pounds) by heating of the rim or tread of the wheel. Such heating
112 BEPOKT OF DIRECTOE OF BUEEAU OF STANDAEDS.

in service is produced by the friction of the brake shoe on the wheel

tread and leads to numerous wheel failures by the cracldng of the

plate. The present investigation will furnish information regarding

the magnitude and distribution of such stresses in different weights

and designs of wheels and should be a basis for rational alterations

in such weights or design as may later be undertaken through the

proper associations. Stresses were produced in these tests equal to

20,000 to ^4,000 pounds per square inch; tliese are close to the

ultimate breaking strength of the cast-iron of the wheel plate.

Work is being continued on the annealing characteristics of castiron, particularly of car wheel compositions. This work is at

present concerned with the effect of variation in sulphur and manganese content in the velocity and temperature of the decomposition

of the white iron carbide. A paper is now in preparation dealing

with certain phases of the analytical methods for the determination

of carbon.

Iron-Carbon System.

Several ingots of pure iron and of iron-carbon alloys have been

cast in the new larga vacuum furnace. These ingots have been

forged, rolled, or drawn into shape for various physical measure- ments and supplied to other divisions of the Bureau or to outside

laboratories for tests. Further thermal analyses have been made of

the various carbon compositions. After the furnaces and transformer are moved to the new chemistry building, it is hoped that

greater progress may be made in this work, and that several n6w

phases may be taken up, including a study of the equilibria of systems other than the iron-carbon one. In this manlier the effect on

steel of different elements, such as sulphur, manganese, and phosphorus, may be studied under ideal conditions, including the elimination of the elements not being studied.

Second Ingot Investigation.

The results of the tests made in cooperation with the Pennsylvania

Eailroad of rails manufactured from different types of ingots are

in shape for the preparation of a published report. The results

include determination of physical properties, microstructure, segregation, etc., and indicate the effect of type of ingot upon the finished

rail.

Ladle Test Ingot Metallurgical Investigation.

Work is being continued in cooperation with the chemical division, with a view to determining the best form of test ingot, as well as the amount of segregation which may be expected in steel ingots.

Gases and Oxides in Steel.

The work on gases and oxides in steel should be extended as soon

as the analytical methods are sufficiently adequate to include a thorough investigation of the effect of these impurities on the properties

of steel. This will include also a study of the effect and efficiency of

various commercial deoxidizers for steel. The chemical features of this work, which include a study of the

best methods for the analytical work involved in such investigations, are covered in the report of the chemical division.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 113

Gun Erosion and Allied Phenomena.

The Bureau has been asked several times by the War Department

for information concerning certain aspects of the gim erosion problem, and therefore the Bureau has undertaken a preliminary laboratory investigation of the behavior of metals when very quickly

cooled from high temperatures. It is believed that practical field

investigation of this problem can be much aided by a laboratory

study of those properties of different metallic materials which are concerned in their service behavior in the form of gun linings. This

•will involve a study of certain properties of these materials at high

temperatures.

Temperature Measurements in Metallurgical Practice.

Within the past three years studies have been made of the feasibility of temperature measurements in steel plants with particular

reference to the measurement of rolling temperatures and those of

the molten steel in the open-hearth furnace, in the Bessemer converter, and during pouring and teeming. It has been shown (see

Technologic Paper No. 91) that the measurement and pyrometric

control of furnace casting and ingot teeming temperatures present

no serious difficulties or uncertainties. For this purpose the most

satisfactory type of instrument is one of the special pyrometers

using monochromatic light and permitting observations from a distance of streams of metal. For streams of liquid iron or steel, the

most probable value of the emissivity to take, using red light

(X=0.G5 jx), is e=0.40. The value of e for liquid slag is usually

about 0.C5, but it varies with the composition. Determination of the

temperature of charge of Bessemer converters is not deemed practicable by such pyrometric methods. The temperature of the openhearth bath is usually kept between 1,600° and 1,670° C.

Thermocouple Nichrome-Constantan.

In connection with work on the distribution of temperature in a cooling rail, a study was made of the suitability of various materials

for thermocouples operating up to 1^000° C. Tests showed that for

immersion in steel at 1,000° C., thermocouple nichrome-constantan

is very satisfactory. It maintains a calibration constant to within

10° C. at 1,000° C. throughout its life; the calibration curve is nearly

linear and shows no departure from a smooth curve.

Failure of Brasses and Bronzes.

During the year publication has been made of the results described

in the report of last year on the subject of the failure of brasses

and bronzes. In addition, the investigation of the thermal expansion

of alpha and of beta brass has been completed, and progress is

reported in the stress corrosion tests of manganese bronze.

The thermal expansion of beta brass, although at ordinary temperatures equal to that of alpha brass, is, at temperatures from 400°

to 450° C., approximately 50 per cent greater than the latter. The

beta grains in a rapidly cooled 60:40 brass containing both alpha and

beta will be in a state of local tension, the alpha grains in compression. This initial stress may be responsible for subsequent failure and

18532—17 8
114 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

cracking in failed brass bolts which have come to the attention of

the Bureau and are known to have been quenched in water. It is

shown also that these local stresses lower the proportional limit of

a brass.

The samples of annealed manganese bronze subjected to corrosion

in a water tank at the Bureau for over six months, while under tensional stresses equal to their proportional limits, have so far shown

no signs of cracking, although slight corrosion has set in. These

tests are to be extended and amplified.

Corrosion of Brasses and Bronzes.

Study has been made of the microstructural features of corro- sion in cast bronzes and in wrought 60 :40 brass of the type of Muntz

metal. This work is being continued with the purpose of ascertaining the structural electrolytic potential differences and the effect of

such differences upon corrosion. A study is also being made of

the effect of stress upon corrosion. It is apparent from the metallographic studies made, both at the Bureau and abroad under the

auspices of the British Institute of Metals, that the corrosion of

brasses and bronzes is most intimately related to the features of

structure.

Impurities in Cast Bronze and Brass,

An investigation has been undertaken of the specific effects of the

usual impurities in cast brass and bronze upon its properties, chiefly

phj'^sical—tensile, hydraulic, resistance, etc. The results of this investigation will indicate the extent to which scrap may be used in

producing castings of these metals and will be a basis for establishing chemical specifications for them. Defects and failure of cast- ings are frequently attributed to the presence of small amounts of

impurities, which should, probably, more properly be attributed to

improper foundry practice in melting and pouring the alloys.

Properties of Commercial Cast Brasses and Bronzes.

Numerous tests have been made at the Bureau's foundry of both

88:10:2 and 88:8:4 (coppei'-tin-zinc) metal cast into a form of test

bar recommended by the Naval Gun Factory (Washington Navy

Yard). This is a core sand cast, cast to size specimen fed along its

whole length. This form of test coupon gives very uniform results

for these medium shrinltage metals. These tests will be con- tinued with the cooperation of five commercial foundries and with

that of the Naval Gun Factory. The results will form a basis for

the defining of specifications for the metals so tested.

Foundry Sands.

Comparison has been made of the mechanical properties of fine

French facing sands and of American ones used as substitutes for

these. It has been shown that one or two American sands are equal

to the imported French sands in every respect except that of tensile

strength. Samples made up of the various sands have indicated that

the tensile strength of the French sands is superior to that of the

American ones. A report is to be made before the American Foundrymen's Association at its fall meeting.
EEPOKT OF DIKECTOR OF BUREAU OF STANDARDS. 115

Deterioration of Tinned Copper Roofing.

The tinned copper roofs of certain buildings have, within some 8

to 10 years after installation, become quite badly pitted. Investigation showed that this pitting is primarily due to the structure of

the tin coating. This coating, produced by the application of molten

tin to the surface of the sheet, contains an alloy layer next to the

copper which is slightly electronegative to it. Such a coating, therefore, gives only a mechanical protection; as soon as the copper is

exposed, galvanic action sets in and the copper is attacked. Plain

copper on some of the buildings had suffered no deterioration under

the same service conditions. Tinned copper must be looked upon as a quite unreliable material for roofing purposes, inferior to plain

copper, and in most cases inferior also to tin plate.

Properties of Electrolytically Deposited Copper.

A preliminary report has been published of the studies of copper

electrodej)osition in electrgtyping baths. These studies have re- sulted in establishing tentative specifications for the deposition of

such copper, concerning the composition of bath, current density, etc. In connection with this work there has been published (Transactions of American Institute of Metals, 1916) an article, giving a description of the microscopic structure of electrodeposited copper.

The occurrence and effect of twinned copper crystals or grains as deposited are discussed. The conclusion is reached that the grain

size of such deposits does not alone determine the physical properties.

Protective Metallic Coatings on Metals.

In connection with the general work on protective metallic coatings on metals, a report has been made giving a comparison of the

basic lead acetate and the hydrochloric acid-antimony chloride

methods of determining zinc on galvanized iron. This work is to be

continued in the direction of comparative service tests (salt spray

test) of zinc coating applied by different methods—sherardized, galvanized, and electrogalvanized.

Fusible Boiler Plugs.

Further investigation has been made within the year of the mode

of introduction of impurities, such as lead, copper, and zinc, into

the tin fillings of fusible boiler plugs. The effect of heating the

tin and the casing to different temperatures on the copper content of

the filling has been determined, and manufacturers have been advised of these results in order that they mny meet the SteamboatInspection Service specifications.

Melting Points of Refractory Elements.

Several additipnal determinations have been made of the melting

points of the most refractory elements, chromium and manganese,

and aj)paratus assembled for the completion of the work. The

melting points of some 140 steels of different composition have also

been determined by optical pyrometer methods.

Cooperation with Military Government Departments.

One of the features of the work of the metallurgical division has

been its greatly increased contact during the last year, and particu-
116 REPORT OF DIRECTOR OF BUREAU OF STAKDARDS.

larly during the past three months, with the military Government

departments.

The Bureau is cooperating with the Bureau of Construction and

Repair of the Navy Department and the Signal Corps of the War

Department in an extensive investigation of light aluminum alloys

for rolling and casting. It is hoped that alloys may be developed of

greater specific mass tenacity than those at present in use. The Bureau has been of some service in connection with the set- ting of certain Navy Department specifications for brasses.

Besides a number of routine tests for the Government military

departments, this division has, often in cooperation with other divisions, conducted special investigations and investigative tests of

very interesting character. Typical instances are corrosion of Muntz

metal bolt, for Boston Navy Yard ; examination of samples of Duralumin alloy used in Zeppelin construction, for Bureau of Construction and Eepair, Navy Department; investigation of failed metal

parts, for Signal Corps, War Department; examination and comparison of zinc coatings on shrapnel tinning leads, Office of Ordnance, War Department; cracking of steel rivets (submarine hull

construction), for Bureau of Construction and Eepair, Navy Department: identification tags of Monel metal for seamen, for Bureau of Identification, Navy Department.

Cooperative Work in Metals.

A feature of the work of the metallurgical division has been its

method of cooperation with technical societies or industries in the

prosecution of its investigational work. In this manner the work it undertakes may proceed upon the very broadest lines and with full

pertinence to industrial practice.

A committee of the American Institute of Metals and other technical societies meets twice a year at the Bureau and discusses the

Bureau's work in nonferrous metals.

Through the membership of its staff members in various committees of the American Society for Testing Materials it cooperates with

this association in its standard work. Such committees are: The

chilled car-wheel subcommittee; the subcommittee on preservative

metallic coatings for metals; the nonferrous metals committee; and

the subcommittee on the methods of analysis of steel.

It cooperates with five commercial and one Navy Department

foundry in its investigation of the properties of commercial brasses

and bronzes, with the Pennsylvania Railroad in its work on sound

ingots, and with the Aluminum Co. of America in its investigation

of light alloys.

Activity in Technical or Scientific Societies.

The results of the Bureau's metallurgical work ha>ve been presented

in papers and discussed before the following societies : American

Chemical Society, American Electrochemical Society, American Institute of Metals, American Societj' for Testing Materials, Iron and

Steel Institute of Great Britain, American Foundrymen's Associauon, Washington Academy of Sciences, American Institute of Mining Engineers, and The Franklin Institute. Several members of

the metallurgical staff are serving actively as officers or as members
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 117

of committees of those technical or scientific societies cooperating

with the Bureau on metallurgical subjects.

Metallurgical Tests.

' A summary of the metallurgical tests is given below; their total

value in fees is $3,666.26. Of these test items, 94 per cent were for

the various departments of the Government and 6 per cent for private individuals and corporations. Many of these tests were of a very important nature, involving considerable investigation and

special installations, and some have served as starting points for

special experimental research.

Heat treatment and thermal

analysis.

Metallographic.

Name.

Irons and

steels.

Nonferrous metals.

Identification

of metal and

process

of manufac- ture.

Metal

failures.

Miscella- neous.

Fusible

plugs.

Brass and

bronze

failure.

Miscella- neous.

Grand

total.

For the Government:

88 19

17 20 126

13 25 2 49 2 270 2 4 11 14 303 Steamboat - Inspection

547 547

2 6 11 19 War Department 9 2 19 1 31

Total 103 2 279 14 71 558 2 4P 1,075

3 4 17 34 fi 64

103 2 282 18 88 558 3() 52 1,139

Information Furnished to the Government and the Public.

Requests are constantly being received for information concern- ing metallurgical topics. Often these are of unusual nature and re- quire much time in preparation. During the past year information

on some 200 dilferent topics has been furnished. In view of this,

steps have been taken to prepare a comprehensive metallurgical .bibliography and file of information to facilitate the preparation of re- plies to such requests.

Circulars of Information on Metallurgical Subjects.

A rather extensive circular of information on copper has been prepared, dealing primarily with its physical properties, and with the

effect of variations in composition and in the conditions of the

process of manufacture upon these properties.

The circular on metals for pyrometric standards is in press.

Eequests for information on certain subjects have been so numerous

that letter circulars have been prepared ; the following subjects have

been covered or are being taken up: The "hardening" of copper;

the heat treatment of steel; welding; brass and bronze; and light

aluminum alloys.
118 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Metallurgical Publications.

The following metallurgical publications and special papers, most

of which have been reprinted in foreign or American technical or

scientific journals, have been issued during the year: Technologic

Paper No. 91, Temperature Measurements in Bessemer and OpenHearth Practice; Scientific Paper No. 296, Thermoelectric Measurement of the Critical Eanges of Pure Iron ; Technologic Paper No. 82,

Failure of Brass: 1, Microstructure and Initial Stress in Wrought

Brasses of the Type 60 Per Cent of Copper and 40 Per Cent of Zinc;

Technologic Paper No. 83, Failure of Brass: 2, Effect of Corrosion

on Ductility and Strength of Brass; Technologic Paper No. 84,

Failure of Brass: 3, Initial Stress Produced by the "Burning-in"

of Manganese Bronze ; Technologic Paper No. 90, Structure of Coating

on Tinned Sheet Copper in Relation to a Specific Case of Corrosion

" The embrittling action of sodium hydroxide on mild steel," published in Metallurgical and Chemical Engineering, May, 1917;

" Notes on the thermocouple nichrome-constantan," published in

Metallurgical and Chemical Engineering, June, 1917; "Some problems in physical metallurgy at the Bureau of Standards," published

in the Journal of the Franklin Institute, July, 1916; "Note on the occurrence and significance of twinned crystals in electrolytic copper," published in Transactions of American Electrochemical Society, 1916; "Preliminary studies in the deposition of copper in

electrotyping baths," published in Transactions of American Electrochemical Society, 1917.

There are also in press or in course of preparation papers on the

following subjects: Thermal expansion of alpha and beta brass;

copper; some unusual features in the microstructure of wrought

iron; typical case of the selective corrosion of Muntz nietal; comparison of basic lead acetate and the hydrochloric acid-antimony

chloride method for determining zinc coatings on sheets and wires;

preliminary report on fine-facing molding sands; determination of

oxygen in steel ; determination of gases in steel ; determination of

cadmium in brass; and determination of graphite in cast iron. \^ A number of investigations have been concluded within the past

year or brought to such a state as to warrant soon the publication of

results.

8 STRUCTURAL, ENGINEERING, AND MISCELLANEOUS MATERIALS.

[Strength, hardness, elasticity, plasticity, permeability, composition, structure, and other

physical and chemical properties of structural and miscellaneous materials, such as cement, stone, clay, lime, paper, textiles, rubber, etc., including laboratory and field work

in developing methods of test, standards of quality, and the relation of quality to the

efiicient utilization of such materials.]

Investigation of Structural Steel Columns.

An important investigation on the strength of steel columns has

been conducted for the past few years in cooperation with committees

of the American Society of Civil Engineers and the American Railway Engineering Association.

The columns comprising the series investigated for the American

Society of Civil Engineers were designed primarily to study the effect

of cro.ss section. Nine different types were fabricated in both light
REPORT OF DIRECTOR OF BUREAU OF STANDARDS, 119

and heavy sections. The original series as outlined comprised three

dilferent lengths of each type and three columns of each length in

both light and heavy sections. This program was later extended to

five diiferent lengths for certain of the types and three dilferent

weights of material.

The series tested for the American Eailway Engineering Association were designed primarily to study the effect of lattice bars and

batten plates, as well as different end conditions. In this series both

light and heavy sections, each with three different lengths and three

<;olumns for each length were tested.

The work of testing of the columns of these two series was completed during the year, and reports on the tests were furnished to the

committees of the two societies.

An exhaustive program has been outlined with a view to determining the quality of the metal from which the columns were fabricated.

The results obtained to date on this supplementary program seem

to account for some of the rather startling results obtained on the

columns tested. This supplementary program is about one-third

completed.

Tliis investigation, comprising a total of 240 columns, is the most

comprehensive investigation that has ever been undertaken on the

strength of steel columns and the results obtained therefrom will be

of great value to engineers and architects as soon as the results be-

<;ome available.

The publication of preliminary reports of the results of these investigations have appeared from time to time in the proceedings of

the respective societies as progress reports. Work is now under way

for the publication of a final report of these committees on these investigations during the coming year.

During the past year the Bureau has received 233 steel columns by

transfer from the Watertown Arsenal. These represent cohnnns purchased in 1908 for an investigation originally intended to be con- ducted at that place. The work of testing these cohnnns has been

postponed until the results of the series just completed may be

thoroughly studied.

Physical Investigations of Railway Material.

The work done during the past year on railroad materials has been

that of investigating the cause of failure of rails previously submitted by various railroad companies. This investigation has included

the determination of the physical properties of various parts of the

rail, as well as tests on complete heads, webs, and bases. In connection with this work, the division has had the cooperation of the chemical and metallurgical divisions in chemical analyses and microscopic

examinations. A number of rails have thus been investigated and

reports of these investigations Avith conclusions have been furnished

the various railway companies interested.

In addition to a study of the physical, chemical, and metallurgical

problems, as usually made, a preliminary study has been made on the

distribution of internal stresses in the various parts of a rail. A sufficient amount of work has not as yet been done to warrant the drawing of any definite conclusions.
120 KEPOKT OF DIRECTOR OF BUREAU OF STANDARDS.

Investigation of the Physical Properties of Zinc.

The investigation on the physical properties of cast zinc has been

carried on during the past year upon material submitted by a commercial company which represents exceedingly pure zinc, and material submitted by another company which represents a grade of zine

containing considerably greater impurities. The investigation comprised tensile, compressive, torsional, cold bend, and hardness tests.. This investigation has been very illuminating in regard to the effect

of small quantities of impurities in zinc. The zinc representing the

pure material was found to be almost entirely devoid of elastic property, while the zinc containing some impurity showed considerable

elastic property. It is hoped to extend this investigation to comprise

other pure metals, and the results obtained will be published as a

technologic paper.

Investigation of Methods of Calibration of Testing Machines.

During the early part of the year considerable work was done on

the ways and means of calibrating testing machines up to full capacity and some very satisfactory results were obtained. Three methods

are being investigated to determine their relative merits, namely i (1) The adaptation of the hydraulic support in combination with a

suitable portable registering device; (2) calibration of vertical test- ing machines by the substitution method; and (3) the use of a series

of standard bars of different sectional areas, in conjunction with a suitable extensometer. This work has been temporarily suspended

due to the pressure of work of a more urgent character.

A chrome-nickel bar 4 inches in diameter and 8 feet long was prepared to be used for checking the constancy of the large Emery

machine in tension. A suitable extensometer was also built in the

shops of the Bureau for use in measuring the elongations of this bar

under stress. This, while far from the ideal, is the only available

method at the present time to keep check on this machine. Its use has

been found fairly satisfactory.

A number of testing machines have been calibrated up to 50,000

pounds by the use of the sensitive levers possessed by the Bureau.

Comparison has also been made of machines of larger capacity up to

800,000 pounds with the large testing machine in the laboratory of

the Bureau. The methods adopted in this case consisted of a tension

bar and the comparison of the elongations obtained on the machine in

question with the elongations obtained for similar loads upon the

Bureau's testing machine. This work, in no sense, can be considered

as a calibration and must only be considered as a comparison of

machines.

Investigation of the Effect of Kiln-Drying Spruce.

The scarcity of good air-dried spruce for the purpose of airplane

manufacture has led to an investigation of the effect of kiln drying

on spruce timber. This investigation is being carried on in cooperation with several furniture manufacturers who have the necessary

facilities for kiln drying the lumber. It is hoped that this investigation will result in a suitable method for kiln drying spruce which will

give a material as satisfactory for use in airplane construction as the

present air-dried spruce. This work has been outlined and is now in
EEPOKT OF DIRECTOR OF BUREAU OF STANDARDS. 121

progress. The results, when obtained, will be communicated to the

Aircraft Board of the Government for their immediate use.

Airplane Strut Investigation.

A tentative outline of the investigation of airplane struts was

submitted to the various airplane manufacturers for criticism and

suggestions before this work Avas begun. The suggestions made are

incoi'porated into the final program in so far as this was possible.

Work is now under way on an investigation to determine a suitable

column formula for u=e in design of airplane struts. This investigation is being conducted upon air-dried spruce and comprises

lengths of L/R from 25 to 250. It is the intention to determine from

this investigation an empirical formula to be used as a guide in the

design of airplane struts, no formula at present being available for

this work.

Resistance of Wood to Alternating Stress.

Investigation on the resistance of various kinds of wood to alternating stress was undertaken some time ago. A few preliminary

experiments were conducted on a machine now in the possession of

the Bureau, but this machine was found to be wholly unsatisfactory

for the work. The results obtained, however, were indicative of the

necessity of such an investigation and a machine was designed and

has been built in the shops of the Bureau. The investigation is now

under way. A sufficient number of tests have not yet been made to

warrant the drawing of any conclusions. A battery of these machines is now being built so that the results may become immediately

available for use at the present time. These results will be communicated to the proper board, when available, for their guidance in

the selection of material for aircraft production.

Study of Strains in Car Wheels.

"Work on the strains produced in car wheels under braking conditions has been carried on in cooperation with the metallurgical diviBion. In this investigation, which is of a preliminary nature, the

various strains produced in the different parts of the wheel were

measured with various temperature conditions of the rim.

As a means of interpreting the measurements made on the wheel

under different temperatures, tensile tests were made upon test bars

cast from the same melt as the wheel. In this test elongations of the

bar were measured for different stresses under a series of temperatures varying from 20° C. to 300° C, representing the range of temperatures used on the wheel.

Machine-Tool Investigations.

An important investigation has recently been inaugurated in co- operation with the research committee of the American Society of

Mechanical Engineers on the cutting action of machine tools. It

is intended to study exhaustively the manner of chip formation as well as the power consumed in the cutting of metals. This is an investigation of exceedingly broad scope and will require considerable

time before any definite results can be obtained. There is at present

practically no literature on the subject which might be used as a
122 BEPORT OF DIRECTOR OF BUREAU OF STANDARDS.

guide in outlining such an investigation. It is proposed to study

different types of tools, different angles of the cutting tools, and

different grades of steels for use in these tools. The Bureau some

time ago purchased a planer dynamometer for this investigation,

but the work has been delayed, as no suitable planer was available.

During the past year an 8-foot by 25-foot planer has been installed

and work is now in progress.

Strength of Galvanized Wire.

The Bureau was consulted by a commercial company relative to

the reason for loss of ductility in wire due to galvanizing. Samples

of this product have been submitted and an investigation is now under

way to determine the reason for this brittleness induced by galvanizing and also to determine ways and means to overcome this

effect. The results, when obtained, will probably be published as

a technologic paper.

Strength of Latticed Aluminum Columns.

This investigation was undertaken at the request of the Joint

Army and Navy Airship Beard, in order to determine safe working

loads for columns fabricated from light aluminum alloys to be used

in dirigible construction. Eighteen columns designed by this board

have been tested and a reporL thereon has been submitted to them.

These columns were of doubtful design and suggestions have been

made to the board for their modification. These suggestions were

acted upon by the board, and other columns are now being fabricated

wliich will be tested by the Bureau some time in the near future.

Failure of Bridge Material.

During the year investigations of the failure of bridge material

have been undertaken. A bridge which had been in service for about

20 years recently collapsed without warning, resulting in the injury

to life and property. This failure is being investigated in order to

ascertain if it is due to the pecidiar characteristics of the material

itself. This work is noAv in progress and the results will be published as soon as completed.

Strength of Bridge Material.

The report on the investigation of the strength of large bridge

columns was presented for publication and is now in press. The

tests were conducted upon 18 columns corresponding to original

members in the long-span bridges recentl,y erected at Memphis,

Tenn., Metropolis, 111., and St. Louis, Mo. The columns ranged in

length from 15^ to 24| feet, and in cross-sectional area from •i2 to

110 square inches, and were constructed of carbon, silicon, chrome,

mayari, and nickel steels. The compression strengths of the columns

were found from the tests to vary from 31,000 to 45,000 pounds per

square inch for the carbon steels and from 47,000 to 61,700 pounds

per square inch for the alloy steels. Most of the columns developed

a strength equal to the yield points of their component steels; 6,

however, failed by local buckling or by bending at the ends. Numerous supplementary tests were made on lattice bars, pin plates,

transverse diaphragms, and other details and the laws of behavior

determined.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 123

An investigation was conducted in cooperation witli a large bridge

manufacturing compan}^ to furnish reliable data upon the behavior

of columns of built-up trusses used in ordinary building construction. The angle columns were tested in lengths from 3 to 25 feet.

The experimental work covering 167 columns is completed and the

data are being collated for publication.

Failure of Hull Material.

An investigation of hull material, with a view to determining the cause of failure of a high tensile plate while being handled at the

shipping yard, was requested by the Bureau of Construction and

Repair. This investigation has been attacked from the standpoint

of internal stresses, a large number of measurements having been

made upon the plates submitted and some very interesting results

obtained. Investigations on the tensile strength and microscopic

analysis of this plate have also been made and the results are now

being studied. A report embodying certain recommendations on

this material will soon be submitted to that bureau.

Investigation of Material from Experimental Bulkheads.

An investigation was also conducted at the request of the Bureau

of Construction and Repair upon material from experimental bulkheads. This investigation comprised physical tests including the

detei'mination of the ultimate resilience of the materials in question,

as Avell as microscopic and chemical analysis of the material. This

investigation has been completed and a report has been submitted to

that bureau.

Investigation of Wire Rope.

The report on the investigation of the strength and other physical

properties of wire rope has been submitted for publication. This

report contains a review of individual tests made upon 275 Avire

ropes ranging in diameters from -j inch to 3;^ inches, inclusive ; also nu- merous supplementary tests of wires, fibers in the hemp cores, lubricants, and preservatives used in the manufacture of the rope. The

investigation covered five of the more important and commonly used

classes of American Avire rope.

A cooperative investigation was made with a prominent bridge

construction corporation to determine the effects of sheaves upon the

tensile strength of steel hoisting rope. The specimens were tested

under conditions approximating those existing in the case of hoisting blocks of derricks and dredges for comparison with direct tensile

tests. The results of the tests showed that the sheaves reduced the

strength in some cases as much as 25 per cent, this depending upon

the diameter of the sheaves, which ranged from 10 to 18 inches. The

report of these tests has been submitted for publication, and it is

believed will be of value to engineering, construction, and erecting

firms.

Strength of Brick Piers.

An investigation of the load-bearing value and other properties of

large brick piers has been completed and is being prepared for publication. This investigation was conducted in cooperation with the

National Brick Manufacturers Association, and includes tests of 50
124 EEPOKT OF DIEECTOR OF BUREAU OF STANDARDS.

brick piers of large size. In the construction of these piers, three

grades of brick from each of four widely separated districts east of

the Mississippi River were used.

A study was made of various types of bonding and of different

grades of mortar. Numerous auxiliary tests were made on the materials used. The methods used in the erection of the test piers is believed to be representative of modern practice in brick masonry,

and the districts represented are such as to give a fair average of

clay-brick product east of the Mississippi Eiver. The following

conclusions are drawn from the results obtained:

The strength of brick piers depends primarily on the quality of

brick and kind of mortar used. Of the mortars used, the cement

inortar develops about twice the strength of the lime mortars, of

SJ.700 and 1,400 pounds per square inch, respectively, for the highest

grade of brick. The cement mortar is harder to work, however, and

a combination lime and cement mortar which does not appreciably

effect the strength of the piers is cheaper, and has much better working qualities. The combination used in the present investigation was

1 part of cement and lime (by volume 65 per cent and 35 per cent,

respectively), to 3 parts sand. The strength of piers laid in the

combination cement and lime mortar was practically the same as those laid in a 1 : 3 cement mortar, giving twice the strength of those

laid in 1 : 6 lime mortar and about four times the strength of those

laid in 1 : 3 lime mortar. The type of bond as concerns the number

of header courses used has little, if any, effect upon the ultimate

compressive strength of the piers. The introduction of wire mesh

in the horizontal joints adds strength if used in all the joints. This

does not apply, however, if used in every third or fourth course only,

and may even decrease the strength of the pier. The transverse

rather than compressive strength of the individual brick is believed

to bear the closer relation to the ultimate strength of brick masonry.

Investigation of the Physical Properties of Earths.

The investigation of the physical properties of earths was undertaken in cooperation with the committee appointed by the American

Society of Civil Engineers to study the subject of a classification

for earths suitable for the needs of engineering practice. Numerous

experiments have been made to study the behavior of various earths

under different conditions of loading, and to determine the most

practicable and efficient form of pressure gauges to use in such investigations. The relative frictional resistances, decrees of compression, and cohesive factors in the case of sand and clay when different

per cents of moisture are present have been determined. The lateral

pressures in earths induced by known vertical loads have been meas- ured and the frictional resistances calculated.

It was shown in the results that a change of density in the earth

of but a few per cent is often accompanied by large changes in its

phvsical properties, especially the relative compressibilitv. The

iriction and cohesion was generally increased with the addition of

different percentages of water in the case of sand. The mean angle

of repose for dry standard sand was found to be 39 degrees, a some- what higher value than that commonly given in eneineering treatises.

The progress report of this investigation will be given in the August,

1917, proceedings of the American Society of Civil Engineers.
REPORT OF DIRECTOR OE BUREAU OF STANDARDS. 125

Information Furnished Regarding Strength of Metals and Alloys.

Services of a consulting nature have been rendered on the strength

of steel, alloys, woods, and similar materials. These inquiries, cover- ing a wide range of subjects, have come from private individuals,

public officials, State and National Government departments, universities and schools, engineering societies, and research labora^tories.

The assistance rendered in this connection is entirely distinct from

that of making tests for the determination of the physical properties

of materials. Many of the inquiries were in the field of design, others

asked for advice on suitable testing machinery and methods of tests. In many cases references to technical literature were sought on

various subjects. Advice on the interpretation of existing specifications has often been given and in other cases has been requested

regarding the modification of existing specifications. Publications of

the Bureau have been furnished whenever the information contained

therein would furnish an adequate response to the inquiry. In other

cases the available engineering literature was searched and references

to suitable articles furnished.

Tests of a Semi-Investigative Nature.

A great many tests have been conducted of a semi-investigative

nature to determine the physical properties on materials as well as

to determine suitable material for certain purposes. Among these

may be mentioned the following:

1. An investigation of the efficiency of welded steel plate, welded

by means of oxy-acetylene and electric processes. These were tested

in comparison with riveted joints to determine the relative merits of

the different methods of construction.

2. An investigation was made of the burglar-proof qualities of a chest for the Post Office Department. This safe was not found to

possess these qualities and the Post Office Department was therefore advised accordingly.

3. An interesting investigation was conducted for the Panama

Canal, in which advice was requested on the purchase of shovels for use on the Panama Canal. A thorough strength test and chemical

analysis was made of these shovels. A comparison of the results obtained on the bid sample and lot shipment was made and recommendations forwarded to the purchasing department of that organization. These recommendations proved so satisfactory that a second

lot was submitted to the Bureau for investigation before purchase

was made.

4. Another investigation conducted for the Panama Canal was a thorough study of machetes and grubbing hoes. This investigation

included physical, chemical, and microscopic examination of the

machetes, with recommendations regarding the material submitted.

Grubbing hoes were submitted to the Bureau for advice as to the

selection of two different qualities of grubbing hoe. After investigation the Bureau advised the purchase of the cheaper grade of hoe; in

fact, the only difference ascertainable was that of price. This will

mean a considerable saving to the purchasing department of that

organization.

5. The question of selection of material for periscope tubing was

submitted to the Bureau for decision by a large commercial company.
126 REPORT OF DIRECTOK OF BUREAU OF. STANDARDS.

Extensive tests were made of two different grades of material sxibmitted and recommendations as to their respective qualities were

made.

6. Hydrostatic tests on a 12-inch oxy-acetylene welded pipe were

conducted, at the request of the Supervising Architect. Suitable

recommendations were made.

7. An interesting test conducted for the Navy Department was

that of the comparative strength of a copper-plated airplane strut

compared with a similar strut not plated. This resulted in an in- crease in weight of about 64 per cent, due to the copper plating and

an increase in strength of about 11 per cent.

8. A number of tests have been made during the past year for the

metallurgical division in an investigation on welded bronzes. Different methods of welding were investigated and the efficiency of

these determined.

9. An investigation was conducted for the Chief of Ordnance of

the War Department on the effect of the substitution of soft material

for cold-drawn material used in the manufacture of heads for

shrapnel shell. This investigation was conducted to learn what effect

this substitution would have on the expansion of the Bourrelet, and

also to determine if any danger would arise by jamming of the shell

in the gun when fired.

10. Advice was also requested relative to the expansion of materials entering into shrapnel, as well as the method to be employed in

determining the yield point of the material. An investigation was

made of suitable instruments which might be employed in this determination and specific recommendations were made, both upon the

method to be employed and the instruments suitable for this work.

Investigation and Testing of Materials for the Signal Corps.

During the past year the investigations and tests relative to materials used in aircraft construction have reached such magnitude that

the office of the Signal Corps has detailed men, assigned to the Bureau and working under its direction, to assist in the execution of

this work.

Tests on the Strength of Materials.

The following is a summary of the testing done in the structural

materials division representing a very substantial increase over the

number and range of tests conducted during the previous year : Tests

for all Government departments, exclusive of the Signal Corps (Aircraft Engineering Division) of the War Department, 613; Signal

Corps, 627; private parties, 122; and other tests, 26; total, 1,388.

The material tested included steel wire ropes of 2^ inches and 3^

inches in diameter, manila rope, steel bars, cold chisels, machine

bolts, brass tubing, conduit pipe, turnbuckles, carriage bolts, bolt

stock, wire, steel rods, dies, structural steel, wood columns, ash,

spruce, safety belts, aluminum alloy piston, propeller wood, fuselage

wire, angle steel, galvanized pipe, acetylene welded pipe, nickel steel

strut, starter shaft, wrist pin, trolley wire, piano wire, cable, rivets,

bronzes, sheet metal, brass spinning rod, copper steam pipe, brass

hexagon nuts, bi-onze bearing metal, steel metal slitting saws, etc. Tests were also made to determine the strength of flanged unions

on pipes of 6, 8, and 10 inch diameters; the strength of couplmgs on
KEPOKT OP DIRECTOR OP BUREAU OP STANDARDS. 127

oil-well casings of the same diameter; two tile walls; 10 individual

hollow building tile, and approximately 100 individual brick for

compression ; 85 wire ropes for tensile strength ; 25 14-inch porcelain

insulators were tested to a proof load of 500,000 pounds; and a

60-ton double-end crane hook Avas tested for proof load of 50 tons.

Investigation and Testing o£ Cement, Concrete, and Stone.

The work done in connection with the investigation and testing

of cement, concrete, and stcne, and similar materials is of three

kinds, namely: (1) The determination of the physical properties of

cements, concretes, sands, crushed stone and gravels, building stones,

plaster, drain tile, and other so-called cement products; (2) the

development and investigation of methods and apparatus for testing

these materials; and (3) the investigation of the durability of these

materials under various conditions, and to a certain extent the development of improved methods of handling and utilizing these materials in actual construction; for example, in the mixing and placing

of concrete, in the application of stucco and plaster, and in the manufacture of drain tile. Standard Specifications for Portland Cement.

Meetings of the joint conference of representatives of the United

States Government, the American Society for Testing Materials,

and the American Society of Civil Engineers, held during the year,

resulted in the adoption of a standard specification for Portland ce- ment. This specification became effective January 1, 1917, for the

use of all offices of the United States Government, and is an improvement over the old specification. Certain essential requirements,

such as strength, fineness, and setting properties, have been increased; certain unessential requirements, such as tests of neat ce- ment, 100-mesh requirement, air and water soundness pats, etc.,

have bean omitted. Other limitations Avhich did not improve the

quality of cement, but were a handicap to certain manufacturers,

such as the low sulphuric anhydride and magnesia limitations have

been made more liberal. The new specification, although an improvement over the old, can not be considered as entirely satisfactory, as there is no test which furnishes specific information as to the

relative value in concrete of tha products of different mills. Further improvement should be possible in the near future with the

continuation of these investigations and researches.

Circular 33, third edition, containing the revised specification for

Portland cement, was issued January 18, 1917.

Foreign Specifications for Portland Cement.

A collation is being made of all foreign specifications for Portland

cement. This information is being obtained through the assistance

of tlie various consular agents. A large number of specifications

have been received from different countries and they will be translated and combined in a paper in the near future.

Effect of Fine Grinding of Portland Cement.

As the result of considerable discussion concerning the value of

fine grinding of cement, an investigation was started in 1915 to de-
128 REPORT OF DIRECTOR OF BUREAU OF STANDARDS,

termine the effact of fineness of cement on its strength and other

physical properties.

The results of the compressive strength tests of concretes, con- taining several brands of cement reground to various degrees of fine- ness, so far obtained tend to confirm the previous conclusions that,

on the average, for each per cent increase in fineness the compressive

strength is increased 2 per cent.

Minor Constituents of Portland Cement.

There is in process of publication the results of work dealing with

the effect of magnesium upon the properties of Portland cement.

This is one of the minor constituents which are usually supposed to

have little or no effect upon the general properties of cement. However, in this work it was shown that a little less than 5 per cent produces a noticeable change in the softening temperature of the clinker,

though otherwise the resulting cement is not deleteriously affected.

The early strengths which can be developed above 7 per cent are decidedly decreased. The other minor constituents are now in course of being investigated, especially iron oxide and the alkalis. The

former retards the setting to a decided degree, but does not materially affect the later hardening. It appears, also, that the alkalis

have the property of making the early setting very erratic, in some

cases causing it to turn quick-setting during storage.

Constitution of Portland Cement.

The investigation which is being carried on in the experimental

cement plant of the Bureau dealing with the properties of Portland

cement as affected by changes in composition has been progressing

very satisfactorily during the year. A considerable amount of time

has been spent in studying the results at hand, especially through

showing the general deportment of the cements in concrete. It

appears from these results that the quantity of the various constituents is a factor of great importance, as well as the condition in which

they are present.

Thus, it seems that if the same mix is burned at two different temperatures, that temperature which produces the finer grained clinker

will produce the most active cement. Very hard-burned clinker,

especially when the constitutents are larger grained or crystalline,

does not appear as active as clinker burned at a low temperature for

a longer period. As a result, thin sections of all clinker in the investigation have been made and are being examined both for the

amounts and the character of the various constituents.

Granulometric Air Analyzer.

The granulometric air analyzer which has been in successful

operation for three years, continues to demonstrate its usefulness in

the quantitative separation of finely ground cements and other

powders. Aside from more or less routine mechanical analysis of

cements, the analyzer has been employed in the study of foundry

clays and moulding sands, and for the separation of carbon, copper,

and emery powders.

Air Separator for Cement.

An apparatus has been devised for the separation of "flour" from

the coarse material of Portland cement by means of air. Flour of
I REPOET OF DIEECTOR OF BUEEAU OF STANDAEDS. 129

3 degrees of fineness are now obtained. During the past year improvements have been made in this apparatus, consisting mainly of

a new feeding device which increases the efficiency of operation, and

a new dust collector has also been designed.

While the air separator is still in the experimental stage, it has

already produced a large amount of fine material which has been

used in the very important investigation of the value of fineness of

Portland cement. Up to the present time this is the only known

device capable of separating the fine particles of cement from the

coarser material in considerable quantity, and at the same time controlling absolutely the degree of fineness of the separated material.

The control both of fineness and gradation is an absolute prerequisite

for success in studying the effect of fine grinding of cement on the

strength of mortars and concretes, and the chief obstacle to rapid

progress in the investigation is the excessive slowness in production

of the fine grades of cement of normal granulometric composition.

Consequently, it is important that the air separator be developed

primarily for larger capacity, and steps have already been taken to

meet this requirement.

Standard Cement Sieves.

Thirty-two 200-mesh sieves have been calibrated during the year

to determine whether they meet the Bureau's modified sieve specification which was adopted in 1914. This service has been of much

assistance to testing laboratories, as a correction factor is furnished

with the certificate of test. The application of this correction factor

makes possible much greater concordance of results than were previously obtainable, thereby preventing many disputes between the

manufacturer and consumer. With the increase in the fineness re- quirement of specifications for cement this work should be of still

greater service to the public. The comparatively small number of

sieves tested this year is an indication of the scarcity of high grade

sieving cloth, which is entirely an imported product, and also that

laboratories and maniifacti;rers are making more and more use of

the Bureau's standard fineness samples.

Standard Fineness Sample.

New cement samples of standard fineness have recently been prepared and made available to owners of cement-testing sieves. These

samples are used for checking the sieving values of such sieves, and

afford a means of comparing the so-called standard sieves with the

fundamental standards maintained at the Bureau. The new samples are slightly finer than those previously issued, conforming more

nearly to the requirements of the cement specifications adopted January 1, 1917.

Hydraulic Cements Other than Portland Cement.

The investigation of the compounds of lime and alumina with

small amounts of impurities of silica, iron oxide, and magnesium

have been continued with most gratifying results. Alumina and

lime burned in the rotary kiln in the proportion of 1 to 1, or 5 to 3

and then ground, give cements which have much greater strength in

concrete than Portland cement. One to 6 gravel concrete gave a 18532—17 9
130 REPORT OP DIRECTOE OF BUREAU OF STANDARDS.

strength of almost 3,000 pounds per square inch at the end of 24 hours.

This showed continuous gain up to six months, when a strength of

7,600 pounds per square inch had been attained. Specimens stored

in the drying closet showed a decrease after this time to 6,700 pounds,

while those stored in the laboratory after this period increased to

8,200 pounds per square inch at the end of a year.

This high strength was due to the quick hardening (but slow set- ting) of the aluminate which is accompanied by the splitting off of

colloidal hydrated alumina. This latter acts as a mineral glue.

That the strength developed is greater than that developed by Portland cement is due to the greater amount of colloidal material

formed.

Durability of Concrete in Sea Water.

The investigation of the effect of sea water on concrete has been

continued and practically all concrete structures on the coasts of

North America, Panama, and Cuba have been examined and reports

have been issued to the Navy Department on several of the yards.

Data are being collated on the condition of concrete and methods

employed in construction of concrete structures in various harbors

of the world. These data are being obtained through the vario'is

consular agents and reports have been received on a large number

of structures.

The investigation has shown that all concrete exposed to sea water, irrespective of location, is subject to chemical disintegration

unless properly fabricated and protected. If sufficient care is taken,

and proper designs and methods followed, the concrete will be

durable. Practically all reinforced concrete structures, including

those owned by the Government and public, in sea water are failing,

due to improper design which causes the corrosion of the reinforcement. The conditions found demonstrate that the designs advocated

by present engineering practice will not insure permanent or durable

structures. It is anticipated that the results of this investigation

will be published during the ensuing year.

Durability of Concrete in Alkali Waters.

The investigation of the durability of concrete in alkali waters

was started in 1913, and was instituted because of its importance to

various branches of the Government using concrete in irrigated districts, where the alkali occasionally becomes concentrated in the soil,

and as a result of the many requests received for information on

the subject. The investigation is being conducted in cooperation

with the Reclamation Service, the drainage division of the Department of Agriculture, and the Portland Cement Association, to determine the durability of concrete of various kinds in concentrated

alkali soils and methods of mitigating failure.

As part of the investigation some 8,000 specially prepared drain

tile made under the Bureau's supervision were installed in concentrated alkali soils in Colorado, Montana, Wyoming, Arizona, Wasliington, New Mexico, and Utah. A number of these tile are taken

up and tested each year. The results of the first year's tests were

published in Technologic Paper No. 44.

As an extension of this work, a large number of concrete blocks

were made using aggregates to be found on the various projects as
EEPOBT OF DIRECTOR OF BUREAU OF STANDARDS. 131

well as an aggregate of known excellent quality at Denver. These

blocks were installed in localities similar to those in which the drain

tile were installed and are to be examined from time to time for indications of disintegration.

A second progress report has been prepared, to be published as Technologic Paper No. 95. This paper contains the results of tests of drain tile made during the first three years and a statement of

the condition of the concrete blocks after one year's exposure. The

results show that concrete and cement drain tile will disintegrate

in some of these soils, unless the best of materials are used and

special care is exercised in fabrication.

The results of tests made in 1916 showed that many of the tile

installed on one of the projects in the Middle West had been attacked

by some agent in the soil or drainage water. There is no alkali

present in the soil on this particular project and the type of disintegration differs from that found in the western drains, where the

drainage waters carry appreciable quantities of alkali salts. Since

thousands of miles of cement tile drains installed in the humid re- fions of the East and Middle West are apparently giving satisaction after years of service, it is not believed that this type of disintegration is general, although it confirms complaints as to the lack

of durability of cement drain tile in widely separated districts of

the East and Middle West, where failures have been found and

previously explained as beiug due to the use of poor aggregates and

improper methods of manufacture. An investigation is being made

to determine the extent and cause of this type of faihire. Additional tests are to be made from year to year and the report amended

as results are available.

Investigation of Integral Waterproofing Compounds.

In compliance with a demand for more definite information con- cerning the value of integral waterproofing compounds, an advisory

committee was organized in 1916, composed of representatives of the

Government, engineering societies, waterproofing companies, and

prominent engineers interested in this investigation, to formulate a program. The program which resulted from several meetings of this

committee contemplated the construction of concrete tanks by contract, both with and without waterproofing compounds, under conditions simulating actual field conditions. All arrangements were completed for carrying out this program, but the increased work incident

to the national emergency has caused the temporary postponement of

this investigation.

During the year a number of waterproofing compounds were tested

in the laboratory. Special tests were made on Toxement waterproofing compound for a Government department to determine the effect

of its addition to concrete upon the density and weight. Its addition

was found to materially decrease the density and decrease the weight

per cubic foot.

Development of an Accelerator for Hardening Concrete.

At the request of the United States engineer office at Memphis,

Tenn., an investigation was made to develop a method of producing

a concrete which would have considerable strength in a comparatively

short time. The results of tests indicate that the addition of a small
132 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

amount of calcium chloride with some cements in 1:2:4 concrete

resvilted in a strength increase of about 100 per cent in 24 and 48

hours. To further substantiate these results and obtain information

as to the durability of concrete containing small amounts of calcium

chloride, a comprehensive series of tests have been started. The

results obtained to date indicate that concrete gaged with a 6 per cent

solution of calcium chloride increases in strength from 60 to 110 per

cent in two and three days. The results of tests up to six months

do not show any detrimental effect from the addition of the calcium

chloride.

Cast-iron Reinforced Concrete Columns.

There is now being prepared for publication the results of tests of

20 concrete columns which contained as an unusual feature cast iron

as reinforcement. This method of reinforcing was proposed by von

Emperger, who used the cast iron in the form of hollow cast-iron

pipe which formed the core of the column. The concrete is cast

around this hollow core, which may, if desired, be filled with concrete,

and reinforced with the usual spiral reinforcing.

The results show that this type of column would be very economical

so far as cost is concerned. The cast iron is not stressed to more

than 60 per cent of its maximum strength when the concrete fails,

and also apparently is strengthened by the concrete, so that all local

weaknesses are eliminated and there is no su(iden failure so common

to plain cast-iron columns. The columns were able to carry stresses

amounting to 10,000 pounds per square inch and like hooped columns

gave pronounced indication of approaching failure.

Floor Construction Tests.

An investigation was made of two types of floors recentlj^^ introduced in Washington. At the request of the District building department, a loading test was made on a " Schuster " two-way reinforced combination hollow tile and concrete floor. For the Navy

Department a test was made on a " Metropolitan " gypsum composition floor reinforced with twisted steel cables. This type of floor

combines strength and elasticity with lightness of construction, and

has been subsequently used by the Navy Department in some of their

new structures.

Investigation of Composition Flooring.

This tei-m is applied to certain noncombustible resilient flooring

preparations in which the binder or cementitious material is " Sorel " or magnesium oxychloride cement. The other ingredients of the

preparation are certain inorganic fillers, such as very finely ground

quartz or limestone, asbestos, wood flour, and coloring agents. The

finished floor has certain properties such as resilience, quietness, and

lack of changes of volume, which allow it to.be used in large slabs.

In order to obtain certain basic information in regard to the

effect of foreign bodies in the ingredients and, also, information in

regard to the effect of varying the amounts of the ingredients usually

used, extended investigations have been started. This Bureau is

malring use of the active cooperation of a newly formed National

Composition Flooring Association which is desirous of having a uniform specification drawn up covering their product.
KEPOKT OF DIRECTOR OF BUREAU OF STANDARDS. 133

This problem is of particular interest at the present time in view

of a necessary change in the source of the magnesite. This latter

material had, imtil the last two years, been obtained from Greece.

When this supply was cut off active prospecting was undertaken in

tliis country and some fairly good deposits located in California.

The problem was further complicated by the fact that the imported

material was delivered in this country in the calcined form. Since

the proper calcination of the magnesite is of fundamental importance, this has been made one of the phases of the investigation.

Value of Various Materials as Concrete Aggregate.

In cooperation with State geologists and others, representative

samples of mine tailings, criished slag, sands, gravels, and stones are being obtained for test to determine their suitability as aggregates for concrete mixtures. A large number of tests have been

made on fine and coarse aggregates from various sections of the

United States. Comprehensive tests of the value of basalt and other

aggregates from the Columbia River district, Washington, were

made. The results of the investigations will be published upon

their completion.

Effect of Moisture and Temperature Changes on Concrete.

Work was continued on the investigation of the action of concrete when subjected to a variation of temperature and moisture

conditions. The present work has been confined to making measure- ments on concrete roads and pavements with the ultimate aim of determining the most effective distance for the spacing of transverse

joints in concrete. During the past year nmnerous measurements

have been made on experimental slabs installed on the Bureau

grounds and on a Delaware road-. These measurements confirm

previous results in indicating that the concrete is subject to a rather

definite annual cycle of changes in volume ; during the wet and warm

spring months an expansion occurs in the concrete, and during the

drier months the concrete contracts.

A portable comparator is being used to measure accurately the

volimaetric changes in various cement mortars and plasters. The

initial work has consisted of determining the contraction which

occurs when a cement mortar obtains its set. Work has been done

with mortars of various degrees of richness and results show that

lean mixtures contract less than rich, and that mortars mixed when

the hiunidity is high contract less than when mixed at the time the

humidity is low. This work is being continued, and it is anticipated

that a report will be issued during the ensuing year.

Tests of Field-Made Concrete for Lincoln Memorial.

Concrete cubes and cylinders of varying consistencies were made

in the field from the concrete as actually used in the construction

of the approaches to the Lincoln Memorial. These specimens were

tested at various ages to determine their compressive strength. The

results showed that the concrete of a consistency suitable for chuting

was of sufficient strength to meet the requirements of the work.

Investigation of Building Stones of the United States.

In connection with the cooperative investigation of building stones

which is being carried on with the United States Geological Survey,
134 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Bureau of Mines, and Office of Public Roads, 50 samples of commercial marble have been tested to determine their compressive strength

in a dry and wet state, transverse strength, perpendicular and parallel to the bedding, tensile strength perpendicular and parallel to

the bedding, percentage of water absorption, specific gravity, porosity, weight per cubic foot, electrical conductivity, coefficient of

expansion, resistance to frost action, resistance to the penetration of

stains, and chemical composition. A report on these tests is now

being prepared for publication.

A collection of the various commercial marbles has been made and

placed on file at the Bureau of Standards. This collection at present

consists of 75 polished slabs 8 inches by 12 inches and represents

the principal commercial marbles of Vermont, Massachusetts, New

York, Maryland, Georgia, North Carolina, Alabama, Missouri,

Colorado, and California. This collection is now exhibited in suitable cases and may be examined by those interested in studying and

comparing the various types of American marble.

Thirty-five samples of sandstone have been collected from the

important quarries of the United States and the work of preparing

test specimens is well underway. The physical properties of these

will be determined in approximately the same manner as those of

the marble.

Various samples of building stones submitted by other Government departments have been tested to determine their ^suitability for

particular purposes.

Stucco and Plaster Investigation.

A series of tests, primarily to determine the comparative durability of various types of plastered metal lath on exterior walls,

w^as undertaken in 1911. The results of these tests, obtained from

the exposure of small panels, indicated the necessity of carrying out

an investigation on a much larger scale. Accordingly a new and

more comprehensive series of tests were planned, the program of

which was put into the hands of an advisory committee consisting of

representatives from the Govei-nment, engineering societies, the

Associated Metal Lath Manufacturers, the Portland Cement Association, the Gypsum Industries Association, the National Lime Manufacturers' Association, the Hollow Tile Manufacturers' Association,

and a number of engineers, contracting plasterers, and specialists.

The recommendations of this committee were followed in the con- struction of a test structure, approximately 200 feet long, 26 feet

wide, and 24 feet high, the exterior walls of which are divided into

56 panels approximately 15 feet wide and 10 feet high. These panels

are constructed of terra cotta hollow tile, monolithic concrete, brick,

gypsum block, plaster board, and wood and metal lath, and are plastered with a number of typical stuccos, the work being carried out

under the supervision of the advisory committee. The structure was

completed in November, 1916.

The first progress report on this investigation has been published

as Technologic Paper No. 70. This report is mainly descriptive,

giving the complete history of the test structure and the individual

panels, together with a statement of the condition of the panels in

April, 1916.
REPOET or DIBECTOE OF BUEEAU OF STANDARDS. 135

In the summer and fall of 1&16 an addition to the test structure

was erected, providing 22 new panels, the specifications for which

were based largely on suggestions obtained from a study of the

original panels, and approved by the stucco committee. A report

on the new panels will be embodied in the second progress report

to be issued during the coming year, in which it is planned to include a full discussion of the results obtained to date, and a tentative stucco

specification setting forth the fundamental requirements of base

construction, mixtures, and application. While this tentative specification will undoubtedly be modified in the light of later developments in the investigation, it will nevertheless make available the

information gathered by the committee from a more comprehensive

study of the subject than has ever before been attempted.

The field examination of stuccos originally planned as a part of

the investigation has been begun by a study of stucco structures from

1 to 20 years old, mainly residences, in the vicinity of Philadelphia,

New York, Boston, Cleveland, Chicago, and Pittsburgh. It is not

planned to publish the results of the field inspection until the country has been more widely covered, but frequent reference to the

field observations, so far as available, will undoubtedly be made in

the second progress report.

The experimental work on interior plasters, which was to have

been begun in 1917, has been postponed, probably for the duration of

the war. Greatly as this work was desired by the committee, there

was no hesitation on the part of any who had contributed to the

funds for erecting the test structure in authorizing its use for laboratory purposes. The temporary and permanent alterations in this

building will not interfere with the future carrying out of the original plans.

Information Furnished Concerning Cement and Concrete.

Many inquiries were received during the year from architects, engineers, contractors, and builders who sought information concerning

methods of waterproofing concrete, the value of waterproofing compounds, methods of construction to be employed in sea water, effect

of using sea water for mixing concrete to be placed in sea water,

physical properties of concretes of various mixtures, the cause of

staining of plaster Avails and ceilings, the relative value of various

concrete aggregates, methods of making magnesite composition

floors, methods of preventing dusting of cement floors, methods of

designing concrete road slabs, suggestions for building code i-equirements, the cause of failure of concrete structures, durability of cement

drain tile, the effect of sewage on concrete, the physical properties

of marbles, methods of treating stone to reduce absorption, specification for stucco, fire-resisting properties of structural materials,

the corrosion of metal lath, reinforcement of gypsum plasters, the

interpretation of cement specifications, methods of coloring concrete, etc. From the general public requests were received for information on

methods of mixing concrete, laying of concrete sidewalks, waterproofing basements, suitability of various materials for use in concrete, durability of concrete in sea water, durability of composition

magnesite floors, the physical properties of stone, the cause of failure
136 BEPOBT OF DIRECTOR OF BUREAU OF STANDARDS.

of drain tile, the effect of frost action on concrete, suitability of concrete for oil and acid storage tanks, quality of American Portland

cements, dampproofing brick and tile walls, dusting of concrete

floors, corrosion of metal lath, etc. From cement manufacturers, architectural stone manufacturers, and

commercial testing laboratories requests were received for information

on the accuracy of selves, methods of standardizing sieves, the physical

properties of concrete, the value of fine grinding, apparatus for

granulometric analysis, cause of failure of drain tile, the interpretation of cement specifications, quick hardening concrete, standard

methods of testing, etc.

Publications on Cement and Concrete.

The following papers on the subject of cement and concrete were

published during the year : Technologic Paper No.' 58, Strength and

Other Properties of Concretes as Affected by Materials and Methods

of Preparation; Technologic Paper No. 70, Durability of Stucco and

Plaster Construction; and Circular No. 33, third edition (revised),

United States Government Specifications for Portland Cement. One

paper is in course of preparation and will be published as Technologic Paper No. 95, Durability of Cement Drain Tile and Concrete in Alkali Soils.

Routine Cement Inspection and Testing of Cement and Concrete.

Cement was inspected during the year at 16 different cement mills,

located in Virginia, Maryland, Pennsylvania, and New Jersey. The

inspection work included the taking of samples, their testing, and

subsequent supervision of packing and shipment to the various departments and offices of the Government. A total of 8,345 samples

were tested for the Navy, War, Treasury, Post Office, Commerce, and

Interior Departments, Panama Canal, Supervising Architect's Office,

District of Columbia, Lincoln Memorial Commission, Smithsonian

Institution, State of Massachusetts, etc. Inspection was made of

295,720 barrels of cement for shipment to Panama and 351,650 barrels for shipment to Government departments in the United States,

for use in the construction of Federal buildings, river and harbor

improvements, and for the State of Massachusetts. Cement was inspected for export for one companj^ and certificates of the quality

were furnished previous to shipment to Argentina. The inspection

of all cement used by the District of Columbia necessitated that an

inspector be stationed permanently at the cement mill in Maryland.

Shipments to the District liave ranged during construction periods

from 1 to 4 carloads daily. During the year 72,000 barrels of cement

were rejected on account of failure to meet the Government specifications.

A considerable amount of cement was made and tested at the

Pittsburgh branch of the Bureau in cooperation Avith various societies in the course of formulating new specifications for Portland

cement. A very large number of concrete cylinders were also tested, as part of a study the Bureau is making of cement manufactured

in its own experimental cement plant.

Seven concrete columns 20 inches in cross section and varying in

length from 5 to 10 feet, taken from a collapsed structure, were
EEPOET OP DIRECTOR OF BUREAU OF STANDARDS. 137

tested to determine whether the concrete was of a satisfactory quality.

These columns proved of particular interest, as they showed to a very marked extent the effect of excessively wet mixes. The fine

material from the concrete had segregated in layers in the column to

a depth of several inches, producing planes of practically no strength,

although through the main part of the column the concrete was of

fair quality.

Miscellaneous Tests of Stone, Sand, Gravel, etc. During the year a total of 355 miscellaneous samples, consisting of

sands, screenings, gravels, stones, asbestos roofing boards, waterproofing compounds, gypsum, magnesite cements, concrete, alkaline soils,

waters, etc., were received for test. Sand-Lime Brick.

It is believed that sand-lime brick of better quality and less cost can

be made by improving the methods of manufacture. An investigation was first undertaken to determine the effect of various factors

upon the properties of a brick-made lime and sand, both of very

fine size of gram, that is, smaller than 200 mesh. A decidedly

stronger brick was obtained with a composition of equal parts by

weight of lime hydrate and sand than with any other proportion.

The best molding pressure was found to be 10,000 pounds per square

inch. Maximum strength was attained by steaming from 4 to 8

hours, longer periods causing a decrease in strength. This result

in steaming was found to occur also with brick containing 10 per

cent lime hydrate and 90 per cent of sand graded from 20 mesh

to dust.

The investigation is being continued, using graded sand to replace

the 200 mesh sand. The factor now being studied is the effect of the

size of grain of the sand upon the compressive strength, trans- verse strength, and absorption of the brick.

Hydrated Lime in Concrete.

Hydrated lime in small amounts is being added to a great deal of

the concrete now being used for various reasons. It is desirable to

know the effect of such an addition upon the properties of the concrete, and with this in view an extended series of tests w^as inaugurated covering the compressive strength, absorption, adhesion to re- inforcing, coeiiicient of expansion, etc., of concrete. A preliminary

resume of the results show as follows

Compressive strength is in general decreased from 1 1© 20 per cent

by additions of hydrated lime, but in some instances the strength is

increased. Strength tests were made upon 1 : 1^ : 3, 1:2:4, 1 : 2^ : 5,

and 1:3:6 concretes of various ages up to one year. Two-year

and five-year specimens remain to be tested.

Additions of lime h3^drate increased the absorption of water by

concrete from 10 to 50 per cent. The order of increase is indicated

by a change of from 6 to 8 per cent absorption in a 1:3:6 concrete.

The adhesion of concrete to steel was decreased from 1 to 40 per

cent by additions of from 10 to 20 per cent of lime hydrate.

Tlie effect of lime hydrate upon the expansion of concrete is being

determined, using bars 4 inches by 4 inches by 4 feet. It is proposed
138 REPORT OF DIRECTOR OP BUREAU OP STANDARDS.

to continue the investigation, determining the effect of lime upon segregation of aggregate and resistance to abrasion.

Measuring of Plasticity and Sand-Carrying Capacity of Lime.

The plasticity and sand-carrying capacity of lime are of great

importance commercially, but no satisfactory method of measuring

these properties has been so far devised. After a considerable number of experiments, an entirely new machine has been constructed

for this purpose. A lime paste or mortar is molded into a cylindrical form and pressure applied by means of a paddle pressed

against the revolving specimen. The tangential and vertical forces

acting upon the specimen are measured and from these the coefficient

of friction is determined. The test is repeated, placing the specimen

upon a plaster block which absorbs water from the paste, causing a more or less rapid increase in the magnitude of the force acting upon

it. From these data the work done upon the specimen is calculated.

A comparatively low coefficient of friction and a low value for

work done indicate a plastic lime. The machine is being tested out

thoroughly by the use of a number of lime hydrates from various

parts of the country.

Properties of Hydrated Limes.

It was found that very few hydrated limes passed the standard

specifications adopted in 1915 by the American Society for Testing

Materials. Consequently 34 samples of hydrate were collected from

various sections of the country and thoroughly tested according to

the existing and to certain proposed specifications. The latter were

adopted as tentative specifications for masons' hydrate by the

American Society for Testing Materials in June, 1917. In order to

aid in drawing up final standard specifications, the examination of

lime hydrates is being continued. In conducting cooperative investigations of this kind, the Bureau is able not only to make reliable

suggestions but also to obtain a very desirable knowledge of the material under consideration as it appears on the market.

Decomposition of Calcium and Magnesium Hydroxides.

The decomposition of calcium and magnesium enters into a number of problems connected with the manufacture, testing, and use of

hydrated lime, since the latter is composed chiefly of calcium hydroxide and sometimes contains more or less magnesium hydroxide.

The temperature of decomposition of these hydroxides and the rates

of decomposition at various temperatures have been determined.

From the results a method is being developed for determining the

degree of hydration of these two oxides in lime hydrates. This is very necessary, as it has been found that lime hydrate which has been

" burned " or had part of the combined water driven off by too high

a temperature during hydration loses some of its plastic properties.

Investigation of Gypsum.

Tliis Bureau is cooperating with a number of manufacturers and

societies in devising methods of testing and specifications for gypsum and gypsum products. The tests investigated and the methods

for conducting them adopted by the committee were: (1) Determina-
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 139

tion of free water for raw gypsum only; (2) fineness; (3) chemical

analysis of raw or of calcined gypsum; (4) precaution for physical

tests; (5) normal consistency ; (6) water-carrying capacity ; (7) dry

bulk; (8) tensile strength; and (9) microscopic investigation.

Architectural Terra Cotta.

The use of certain burned clays in the molded or cast form, known

as architectural terra cotta to distinguish it from terra cotta or hollow

building tile, is increasing very rapidly, supplanting to a certain degree cut stone and architectural metals. As a larger part of the

output is placed on the exterior of buildings, where it is subjected to

all the severe weather conditions of this climate, it is very essential

that it must have certain weather-resisting properties. It is also

in certain unforeseen cases called upon to take stresses induced by

movements of parts or the whole of the structure.

Under these conditions it seemed desirable to determine the physical

characteristics of terra cotta as now manufactured in order to ascer- tain if it is possible to improve the present method of manufacture

and also to study its use and methods of placement in structures.

This investigation will begin with a study of the various clays used

and will follow the material through its various stages until its final

placement on the structure.

Investigation of Tile and Tile Walls.

A report of the results of tests on about 200 hollow building tile is

being prepared for publication. These tile developed strengths ranging from 4,000 to over 10.000 pounds per square inch when tested on end and about one-half to three-fourths of these amounts when

tested on edge or flat. The tests made to determine the relative degree of absorption of water showed values ranging from 6 to 11 jDer

cent; a, vitrified tile to the same scale of hardness ranging between

1 and 2 per cent. The strength of the tile was found to decrease

almost directly with its degree of absorption.

The tile program also includes the testing of walls of widths from

3 to 6 feet ; of from 6 to 8, and 12 inches in thickness ; and of uniform

heights of 12 feet. The strength of a wall tested in this manner

varies approximately from 200,000 to 600,000 pounds, depending on

the thickness of the wall. About 10 walls have been tested and the

work will be continued for the present year. The program is being

carried out in concert with other laboratories, each laboratory en- deavoring to cover the different geographical clay and manufacturing

districts.

Silica-Brick Investigation.

The extensive study of silica refractories, begun in 1916, has been

practically completed. Several important facts have been brought

out in connection with this work. Thus it has been found that wellburned silica bricks should show a specific gravity of not more than

2.36, and upon refiring to 1,500° C. a linear expansion of not more

than 2 per cent in terms of the original length. Simple tests of this

kind offer a ready means of detecting inferior products, a fact of

considerable importance to the by-produce coke oven and the steel

industries, which largely depend upon the use of silica refractories.
140 KEPOET OF DIRECTOR OF BUREAU OF STANDARDS.

Study of American Clay Refractories.

For the purpose of assisting in the classification of American clay

refractories, a large number of fire bricks have been examined with

reference to their softening temperature, their ability to resist a pressure of 40 pounds per square inch at 1,350° C, and their volume

and porosity at various temperatiires up to 1,500° C. Since most of

the domestic makes are represented in this series of tests, the information should be of a fundamental character and useful in the preparation of specifications governing their use.

Special Refractories for High Furnace Temperatures.

In meeting very severe furnace conditions which prevail when

crude oil is used as a fuel, as under marine boilers, the employment

of refractories possessing a wide margin of safety would be very desirable, since these Avould make it possible to force combustion when

occasion requires it. A studj'- of special refractories for this purpose

was made and resulted in the production of bodies consisting of calcined high-grade flint clay with kaolin as the bonding material,

which are capable of standing up under extremely severe conditions,

both as to temperature and pressure. Still more refractoi-y bodies

were produced from a mixture of kaolin and alumina, partly precalcined, which approach the composition of sillimanite, AlgOgSiOg.

For very high temperatures a composition was developed consisting

of 84 parts (by weight) of magnesite and 102 parts of calcined

alumina, intimately blended and fired to a high temperature. Crucibles were made from this mixture, which corresponds to that of

magnesia spinel. These were able to resist a temperature of 1,700° C.

very satisfactoril3^ Materials of this type formerly were produced

only by the Royal Porcelain Manufactory at Berlin. v Study of Ceramic Kilns.

With the constant increase in the cost of coal the fuel consumption

of ceramic kilns and furnaces has become a question of national importance. It is evident that kilns of the greatest thermal efficiency

must be employed and the firing processes must therefore be con- ducted economically. This subject received attention during the past

year in the study of a new type of kiln, the so-called tunnel kiln, an

installation of which, in New Jersey, was closely examined with ref- erence to its heat efficiency, temperature distribution, and character

of heat losses.

A kiln of the older, down-draft type, but fired with producer gas,

was made the subject of another study. This kiln, located in Indiana,

was tested in a similar manner, and incidentally information was collected concerning the advisability of using producer gas as a fuel for

periodic kilns. These reports have been completed and will appear

in the form of a technical paper.

American Plastic Bond Clays.

A study of 28 domestic plastic fire clays suitable for use in the

manufacture of glass pots and graphite crucibles has been completed.

It has been shown that from the standpoint of quality the domestic

materials are available, which make possible the replacement of the

clays formerly imported from Europe. Attention, however, has been
REPORT OF DIRECTOR OP BUREAU OF STANDARDS. 141

called to the necessity and desirability of blending two or more clays,

thus replacing the old practice of depending upon a single clay.

Emphasis has been placed upon controlling the properties of the

mixtures which are impossible when only one clay is used. In spite

of the difficulties now being experienced by manufacturers of such

refractories, the principles enunciated should prove of value in building up a sound practice. In the paper on this subject now in preparation both the European and the American methods of manufacturing

glass refractories and crucibles are reviewed and described.

Sizing of Calcined Clay.

The sizing of the grains of calcined clay in mixtures used for the

making of glass pots, crucibles, sanitary ware, etc., has a very important effect upon the resulting structure of the fired product. The

results obtained by varying the amount of each size of grain for

different purposes have been worked out in an elaborate investigation, which has been completed and is being submitted for publication.

Clay Tests.

Approximately 300 tests of clays have been made for State geologiT

cal surveys and private individuals, especially with reference to finding new sources of kaolins, plastic bonding, and paper clays. Several

new deposits of suitable clay have thus been located in Alabama. A

number of clays have also been tested with reference to their adaption to new uses, especially in connection with the manufacture of

chemical stoneware. In several instances detrimental properties of

clays now being used have been detected and attention called to their

defects.

Porcelain Investigation.

In the continuation of the study of porcelains the scope of the work

has been greatlj^ extended and now includes practically the entire

field of hard-fire porcelains based entirely on the use of domestic

clays and kaolins. New features have also been introduced by re- placing the quartz (flint) by calcined kaolin, artificial sillimanite,

fused alumina, and zirconium oxide. Similarly, the feldspar has

been replaced, either wholly or in part, by eutectic combinations of

kaolin, quartz, and magnesia. In this manner it has been found possible to produce entirely new types of porcelains with characteristic

properties. Such properties as the softening temperature, the vitrification range, and the volume changes which the porcelains undergo

are being determined for each of the 90 porcelain compositions.

Porcelain for Spark Plugs.

The insistent demand for spark plugs capable of standing up under

severe use in aeroplanes, tractors, etc., has been the incentive for con- ducting experiments aiming to produce bodies capable of giving

maximiun service. For this purpose the compositions of the French

and German special spark plugs have been reproduced and are now

being tested for dielectric strength in the laboratories of the Bureau.

Additional hard-fire porcelain compositions are likewise being tried

out for this purpose.
142 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Enameled-Iron Investigations.

Two technical papers are in course of preparation on this general

subject, one dealing with the manufacture of enameled cast iron and

the other of sheet-steel products. Although these industries are rapidly increasing in magnitude and importance, the technical literature relating to the processes involved has been very meager and

sometimes misleading. In the work now in preparation the attempt

will be made to cori;elate the information available and to bring out

principles not generally recognized. A comparison is also being

made of American and foreign enameled products.

Optical Glass Investigation.

The work on optical glass progressed as far as it could with the

laboratory equipment available. For this reason, during the latter

half of the fiscal year a larger furnace was installed capable of holding one pot carrying a charge as large as 1,000 pounds. With this

unit, it has been found possible to make successful melts of crown

and prism glass. Experiments are being conducted upon other

glasses which are in demand.

In order to increase the rate of progress in this work, a new kiln

house with eight melting furnaces and suitable molding and testing

equipment is being erected.

Pots for use in connection with optical glass are now being made

from domestic raw materials for the purpose of developing suitable

compositions for special glasses which are very severe upon the clay

mass of the pot.

Investigation of Lubricating Oils.

The test for demulsibility or resistance of an oil to emulsification

was reported upon last year. A description of this test, published by

the Bureau as Technologic Paper No. 86, aroused so much interest

among refiners and consumers that the Bureau's supply of copies for

free distribution was exhausted within a month. The Panama Canal

has incorporated this test in specifications for steam turbine oil. The determination of viscosity so that it may be expressed in some

rational unit is a matter of much importance, as the vague units

in common use frequently lead to confusion. Considerable work has

been done toward the standardization of the Saybolt Universal Viscosimeter, but the completion of this investigation has been delayed

by the great amount of war work on hand. A preliminary account

of this work has been published in a paper presented before the

American Society for Testing Materials at Atlantic City and a technologic paper has been prepared which gives a more complete

account of the method of determining absolute viscosity.

Information Furnished Regarding Lubricating Oils.

Ordinarily, tests are not made for private parties, but many re- quests are received from large consumers for advice concerning the

testing of oil. A very large amount of correspondence has been con- ducted during the past year in compliance with such requests. Addresses have also been delivered before associations by representatives

of the Bureau concerning the testing of lubricating oils.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 143

Investigation of Leather.

There are differences of opinion among tanners, manufacturers,

and consumers regarding the relative value and wearing quality

of different tannages of leather used in the manufacture of shoes and

no satisfactory specification or method of test has been developed.

The problem is of special importance at the present time in view

of the large quantity of leather required for military purposes.

This situation has caused the Bureau to take up an investigation

of the subject and the hearty cooperation of the National Association

of Tanners has been secured.

During the past year experiments have been conducted, with very

encouraging results, with a machine designed for testing the wearing

quality of sole leather. Interesting experimental results have been

recently obtained in testing the wearing quality at different parts of

the hide. The results obtained, when considered in connection with

an examination of the leather tested, were pronounced by a number

of leading sole-leather tanners to be in accord with the known variation in wearing quality as learned by years of experience. This

fact may be offered as strong evidence in favor of the value secured

by the testing machine. If the machine gives true indications of

the relative wearing quality at different points of a hide, it may be

assumed that its results will indicate correctly the wearing quality of

different leathers.

Experiments will be continued to include the different tannages of

commercial leather with the view of determining their relative wearing quality. The wearing quality will be studied by comparing the

results obtained with the Bureau's testing machine with the results of

actual service tests. Other physical properties will be studied and

chemical analyses will be made in order to develop standard specifications and methods of testing. Tests will also be made to determine the relative wearing quality of sole leather as compared with the

numerous leather substitutes.

Investigation of Shark and Other Fish-Skin Leather.

The Bureau, in collaboration with the Bureau of Fisheries, is investigating the problem of tanning shark and other fish skins. A

large number of skins have been distributed among the various tan- ners who are experimenting with the methods of producing tanned

skins of a quality that may be used as a substitute for certain grades

of leather. The experiments have not been entirely successful in all cases, but a number of tanned sldns submitted for test have given very

encouraging results. The Bureau is investigating the physical properties of the different tannages and it is thought that further experiments will develop methods of tanning by which fish skins may be

made into leather adapted for many useful purposes.

Experimental Rubber Plant.

Some progress has been made in studying the physical properties

of rubber, but a very limited amount of time could only be devoted

to this subject on account of the great amount of routine work.

Additional data have been secured on the effect of dry heat on rubber

stationery bands, rubber insulation of wire, and rubber compounds

in general.
144 REPORT OF DIRECTOR OF BUREAU OF STAKDARDS.

The machine designed at the Bureau for testing the wearing

quality of sole leather has been used experimentally for studying

the relative wearing quality of rubber compounds such as are used

for the tread of pneumatic tires. Eighteen compounds have been

experimented with and the results indicate that the apparatus may

be adapted for testing the wearing quality of tire stock and rubbercomposition soles.

The Bureau's experimental rubber-mixing plant has been handicapped to a great extent during the past year by the unusual demands

for special tests along other lines.

Eight rubber compounds were mixed and vulcanized into sheets

in connection with a study of the aging properties of rubber.

About 50 pounds of crude rubber were washed and dried and 19

rubber compounds were mixed and vulcanized for experimental

purposes.

Investigation of Solid-Rubber Tires for Motor Trucks,

The Bureau is investigating the physical and chemical properties

of solid-rubber automobile tires for the War Department. Tires of

different manufacturers have been secured and experimental work

is already under way to ascertain the physical and chemical characteristics of the different rubber compounds used, with the object

of establishing definite specifications and methods of testing.

Rubber Eye Shades for the Range Finders of Battleships.

During the fiscal year 1915 the Bureau conducted experiments for

the Navy Department with the view of producing a rubber compound that would be suited for eye shades to be used in connection

with the range finders of battleships. Numerous trial compounds

were mixed and vulcanized into eye shades which, after being subjected to service conditions for about six months, were returned to

the Bureau for examination. Several of the samples were found to

have given good service and of these a compound Avhich showed no

perceptible deterioration was selected as a standard and will be

specified in placing orders for eye shades in the future.

Cooperation with Technical Societies, Manufacturers, and Consumers. The Bureau is actively cooperating with the American Society for

Testing Materials and with a number of testing laboratories representing manufacturers and large consumers in the development of

specifications for rubber goods^ such as insulated wire, rubber hose,

rubber belting, valves, insulating and friction tape, etc. Work of this sort is of a distinct value in keeping the Bureau in

touch with the progress of manufacturing practice and the Bureau's

research laboratory serves a very useful purpose in affording facilities

for careful and accurate determinations of the physical properties

of rubber.

Assistance Rendered Government Departments.

The Bureau acts in an advisory capacity for the various Government departments in furnishing specifications for miscellaneous materials and in making reports covering the results of tests in connec-
EEPORT OF DIKECTOE OF BUREAU OF STANDARDS. 145

tion with supplies furnished on contract or submitted with competitive bids. The following instances illustrate the nature of this

service

The Bureau assisted in the preparation of specifications for rubber dredging sleeves by request of the Chief of Engineers, War

Department.

A test for the resistance of oils 'to emulsification, which was developed at the Bureau, has proved satisfactory in specifications and

has been adopted by the Panama Canal.

Thirty-two samples of inner tubes for automobile tires were submitted under competitive bids to the Post Office Department. The

-Bureau's report covering the results of physical and chemical tests

of these tubes was used as a basis for awarding the contract.

Fourteen samples of rubber bands were tested for the Post Office

Department, the General Supply Committee, and the Panama Canal.

The Bureau's reports were used as a basis for the award of contracts.

Information Furnished on Physical Tests of Rubber and Leather.

Numerous requests have been received for information regarding

the testing of rubber and leather and for the results of the Bureau's

experimental work along these lines. As a rule, these requests come

from the more progressive manufacturers who realize the advantages

of reliable laboratory tests in developing their products and in maintaining uniformity in the quality of their raw and manufactured

materials. In the majority of cases referring to rubber the desired

information is supplied by reference to Bureau Circular No. 38,

third edition, which illustrates and describes the apparatus and

methods of testing rubber developed at the Bureau and also gives

the results of experimental work in determining the physical properties of rubber.

Special Tests of Miscellaneous Materials.

There have been made during the past year 136 special tests, some

of which were of an experimental nature requiring detailed attention and special equipment. Under this head may be mentioned the

following

Samples representing 500 feet of cotton rubber-lined hose purchased by the District of Columbia Fire Department were tested

according to specifications prepared expressly for this material. Five

samples of cotton rubber-lined fire hose were tested for the Panama

Canal and 20 samples of linen fire hose were tested for the Office of

the Superintendent, State, War and Navy Building.

Twelve samples of tanner shark and other fisliskins were tested

for strength and stretch. In one case many tests were made to determine the relative tensile properties at all points of the skin.

Three tanned calfskins were tested to determine the relative

strength and stretch at all points of the hides.

Twenty-four samples of sole leather were tested .under different

conditions to determine their wearing quality.

Eighteen samples of different rubber compounds were tested for

wearing quality.

Three samples of rubber hospital sheeting were tested for a manufacturer of this material.

18532—17 10
146 REPORT OF DIRECTOR OF BUREAU OF STANDARDtS.

A sample of pneumatic tire for use in connection with airplanes

was tested for the Signal Corps of the War Department.

A sample of cotton rubber-lined fire hose was tested for the Department of Engineering, city of Hartford, Conn.

Tests of Miscellaneous Materials.

During the past year a total of 956 miscellaneous samples were

tested, including the following items, Avhich are rei^resentative of

the materials handled: Rubber hose, 156; packing (asbestos, rubber,

etc.), 200; rubber-covered wire, 189; leather belting, 47; canvas belt-' ing, 25 ; hack-saw blades, 122 ; and sole leather, 19.

The majority of these tests were made at the request of the Panama

Canal and the General Supply Committee, in connection with contracts for Government purchases. Numerous tests were also made

for the various Government departments and for manufacturers

who lack the special facilities offered by the Bureau's laboratory.

Comparison of Cotton and Wool Flags.

A series of exposure tests have been made upon flags made from

cotton and from woi'sted bunting to determine under what conditions it would be desirable to use the cheaper cotton material. The

large and increasing consumption of bunting has made this question one of considerable importance. This investigation has been

completed and the results will be published soon in a technologic

paper of the Bureau entitled " Comparative Durability of Cotton

and Wool Flags."

Identification of Textile Fibers.

Any scientific examination of a textile material presupposes a knowledge of the kind or kinds of fiber of which it is composed.

This information, w^hen lacking, may usually be best obtained by a microscopical examination. The Bureau has recently purchased a photomicrographic outfit which will greatly facilitate and improve

this branch of the work.

Sewing-Machine Stitches.

Tm'o of the more common types of stitches have been compared as

to the relative ability of the resulting seams to resist breaking when

subjected to tension applied perpendicularly to the direction of the seam. Tests were made both with the seam intact and with one or both of the constituent threads cut at the middle of the test piece.

Technologic Paper No. 96, Comparative Tests of Stitches and Seams,

gives in detail the methods of test used and the results obtained.

Tensile Strength of Fabrics.

One of the most useful methods of estimating the quality or durability of a fabric is to study the effect upon it of tension applied in

the direction of each of its sets of threads. The rate of stretching

under uniformly increasing tension is of particular interest in con- nection with fabrics to be used for structural purposes. A curve- drawing apparatus has been designed and attached to one of the

Bureau's strength-testing machines for automatically registering this

effect. There has also been designed a new testing machine which
REPOET OF DIRECTOR OF BUREAU OF STANDARDS. 147

ma}^ be manipulated at A'arious speeds, giving a large variety of

methods of loading. This machine will be found useful in studying

the effect upon the tensile properties of fabric of alternations in the

manufacturing processes. For securing the desired atmospheric condition for this work an instrument has been installed which automatically regulates the moisture.

Textile Conference.

During May the second conference relating to the technical consideration of textile materials was held at this Bureau. A large

immber of technical and scientific men attended the meeting and the

papers presented were very well received. A full report of the

proceedings will be published by the Bureau shortly. It is expected

that a similar meeting will be held next year.

Information Furnished Regarding Textiles and Textile Testing.

A great many requests have been received by the Bureau for

information regarding the testing and properties of textile materials.

These inquiries are very often suggestive of new phases of research.

The various departments of the Government require specifications

to regulate purchases and, when desired, this Bureau assumes the

responsibility of writing these specifications.

Testing of Textiles.

This Bureau has made tests of a routine nature upon 3,492 samples

of textile materials. Included in these materials were a large variety

of commercial grades and kinds of fabrics, twine, thread, yarn, waste,

and loose fiber.

Buttermilk Casein as a Paper-Sizing Material.

Casein is the principal proteid in milk and as such has a high food

value. Cheese contains both the fat and the casein of the milk, butter contains the fat only. Since the manufacture of butter is more

profitable than the manufacture of cheese, there is always a considerable quantity of both skim milk and buttermilk. The skim milk

and buttermilk contain the casein of the original milk. The casein

may be recovered by various processes, and it finds an . extensive use

as the adhesive by which a film of clay or other similar material is

bound to a sheet of paper. The finished paper, known sls coated

paper, has a very smooth surface well adapted for the reproduction

of photographs and for the printing of high-grade illustrations.

The casein investigation was started at the request of the Dairy

Division of the Bureau of Animal Industry. Department of Agriculture, and is a joint investigation with it. Its end of the problem

has been a study of the production of skim and buttermilk caseins,

while the application of casein in the paper industry is being developed by the Bureau of Standards.

Almost all paper makers expi'ess a strong preference for the French

caseins. This does not seem to be due to any necessary inferiority

of the domestic product, but rather to the fact that domestic producers do not turn out a uniform product. Different users express a preference for casein made in different ways. Casein made from

buttermilk or from a mixture of buttermilk and skim milk can be
148 EEPOET OF DIRECTOR OF BUREAU OF STANDARDS.

used, but does not seem to be a standard product. Certain mills

claim that they find some of it suitable. Others have not been able

to use it at all. Since the origin of a casein can not be told definitely from its appearance, it is likely that the expressed opinions of

the industry can not be taken as final. Any investigation which will

tend to bring together the user and the manufacturer of casein; to

improve the domestic product, both as to quality and to uniformity

and to encourage the use of milk which would otherwise be wasted

can not fail to be of benefit. At this time it must not be overlooked

that this product has a distinct food value and that it should be the

aim of the manufacturer to use for this purpose milk which could not

be used for food under the existing circumstances.

The particular purpose of the investigation is to establish the most

suitable methods for the production of skim milk and buttermilk

caseins, devise methods for testing the finished product, and to

study the best methods for its use in the paper industry.

Domestic Clays in the Paper Industry.

The examination of imported and domestic china clays for use as a paper filler and as a coating material for paper is being continued.

Its purpose is to determine those characteristics which produce the

best results in the paper industry. The clays are being examined,

both chemicalh' and physically, together with tests to determine the

rate of slaking, color of the clay, and water mixture, etc. It is the

purpose of this investigation to replace the imported clay by a suitable domestic clay.

Paper-Testing Devices.

The necessity for standard methods of testing materials has spread

to the paper industry, and a demand has been created for testing

devices, the results of which may be interpreted in terms of the

quality of a paper to be used for a particular purpose. The testing

devices now in use are not entirely satisfactory, as they are of the

empirical type. Data from a series of comparative tests, using

several of the well-known testing devices, have been secured and are now being compiled. Certain changes are also being made in these

testing devices, together with a study of some of the more common

faults found. The results of this investigation will place the test- ing of paper on a firmer basis and provide means for securing more

accurate data relating to the quality of a particular paper.

Utilization of Waste Paper for Remanufacture into Paper.

The utilizatiori of waste paper for remanufacture into white paper

is growing in importance each vear. At the present time over 25

per cent of all paper made is collected for remanufacture and a very

large part of this material is used in making white papers. The

present methods, however, are very wasteful in that a large percentage of the material is lost in the recovery process. It is the

purpose of this investigation to study the present recovery methods,

particularly with regard to the effect of the chemicals used and the

loss due to overheating.

Paper Bags for Shipping Cement, Lime, and Gypsum.

The investigation to determine the most suitable paper for use in

the making of cement, lime, and gypsum bags has been completed as
REPORT OF DIRECTOR OF BUREAU OP STANDARDS. 149

far as the laboratory tests are concerned. This work has involved

a long series of tests, including all those tests regularly applied to

paper, together with several tests especially devised for the purpose.

The results so far are not such as will enable definite conclusions to

be drawn. This is due to the fact that it has been impossible to make

a satisfactory connection betAveen the laboratory data and actual service conditions.

No reliable information could be secured from either the user or

the manufacturer of bags, because no systematic tests were being

made. In some cases bags that were condemned as being entirely

unsatisfactory proved by a laboratory test to be of a high quality.

The reverse of this has also been experienqed and such conflicting

conditions have made it difficult for the laboratory to put the proper

interpretation upon the laboratory results. In several cases it has

been shown that proper bags were being improperly used, thereby

causing excessive breakage and condemnation of the iDag. These

conflicting data have necessitated the development of a service test for the laboratory by which it is hoped to interpret the laboratory

data into actual service conditions.

Manufacture of Filter Paper.

Filter paper is used in all chemical laboratories and in large quantities in industrial work for filtering out fine suspended particles

from a liquid. The highest quality of filter paper is imported and

under present conditions it is almost impossible to obtain it. Many

inquiries have been received at the Bureau, asking if it was possible

to obtain domestic filter papers of suitable quality. None is made

in this coimtry and therefore an investigation as to its manufacture

has been started at the Bureau. Samples of the best grades of

imported papers have been obtained and they are being subjected to

a series of tests to determine their physical and chemical properties.

Filter papers must have a very low percentage of ash, a rapid rate

of filtering, and must be free of certain constituents. The chemical

treatment after manufacture is highly important and, so far, this

final chemical treatment has not been satisfactorily Avorked out. It

is proposed to continue the investigation along this line, as the final

chemical treatment determines the quality of the paper.

Information Furnished Concerning Paper.

Assistance was rendered in the preparation of definite specifications covering the general needs of the various branches of the

Government service. Work of this kind is continuous as there is a constant demand for pulp and paper products to meet special uses and the constantly changing requirements of the Government service.

Continuous assistance is required by the Congressional Joint Committee on Printing, the Gen'feral Supply Committee, and the Post

Office, War, and Navy Departments.

Inquiries covering a very wide range have been recei^^ed from the

pulp and paper industry. While most of these have been handled

by mail, in many cases the persons interested have visited the Bureau

in order to study the methods in use at first hand. Among the

visitors have been chemists and engineers of large manufacturing

establishments, representatives of trade associations, and persons
150 EEPOET OF DIRECTOR OF BUREAU OF STANDARDS.

engaged in the paper business. Several of them have been interested

particularly in the experimental paper-making equipment of the

Bureau, Avith a view to introducing something of a similar nature

in their own establishments.

The Bureau always endeavors to aid manufacturers who may have

difficulty in making satisfactory deliveries on Government contracts

and many suggestions have been made during the year to such manufacturers. Many requests for the standard samples and specifications used by the Goverinnent have been received and complied with,

and in addition to this many specifications have been prepared to

meet the requirements of paper for special uses. Attention has been given to the utilization of certain waste materials, due to the large number of such inquiries continually being

received.

Many visitors have been shown through the paper laboratory and

the nature of the work explained to them. This has helped to

spread among the trade a knowledge of the facilities of the Bureau

and in many cases has shown the manufacturer where the Bureau

could be of material assistance to him.

Paper Testing.

During the past year the Bureau has tested 3,095 samples of paper,

3,033 for the Government Printing Office and the Government departments and 62 for public and private interests.
III. OFFICE.

Publications.

During the fiscal year just ended the Bureau issued 67 publications, of which 61 were new and the i-emainder revised editions.

Approximately 56 publications were reprinted, owing to* the large

demand for those papers. The new publications included 4 numbers

of the Bulletin of the Bureau, which completes the thirteenth volume

of the scientific papers. There were also issued 28 new scientific

papers, 20 new technologic papers, 9 new circulars, and 3 new miscellaneous publications.

The following new scientific papers were issued during the year:

A Study of Inductance of Four-Terminal Resistance Standards

Sensitivity and Magnetic Shielding Tests of Thomson Galvanometer

for Use in Eadiometr}^; Volume Effect in Silver Voltameter; Constants of Spectral Eadiation of Uniforml}^ Heated Inclosure or Socalled Black Body, II ; Summary of Experiments on Silver Voltameter at Bureau of Standards and Proposed Specifications; Determination of Aluminum as Oxide; Calculation of Planck's Constant

C, ; T^Tieatstone Bridges and Some Accessory Apparatus for Eesist- ance Thermometry ; Damping of Waves and Other Disturbances in

Mercur}' ; A Variable Self and Mutual Inductor; System of Remote

Control for Electric Testing Laboratory; International System of

Electric and Magnetic Units; Saccharimetric Normal Weight and

\ Specific Rotation of Dextrose; Freezing Point of Mercury; Determination of Degree of Uniformity of Bars of Magnetic Standards;

Thermoelectric Measurement of Critical Ranges of Pure Iron ; Study

of Electromagnet Moving Coil Galvanometei-s for Use in Alternating-Current Measurem.ents ; Standard Substances for the Calibration

of Viscometers; An "Average Eye" for Heterochromatic Photometry, and Comparison of a Flicker and an Equality-of-Brightness

Photometer ; Emissivity of Straight and Helical Filaments of Tungsten; Aneroid Calorimeter for Specific and Latent Heats; Wave

Lengths of Stronger Lines in Helium Spectrum; Relative Sensibility of Average Eye to Light of Different Colors and Some Practical Applications to Radiation Problems; Calculation of Constants

of Planck's Radiation Equation; Extension of Theory of Least

Squares; Luminoiis Radiation from Black Body and Mechanical

Equivalent of Light; Experimental Study of Fahy Permeameter;

Note on Electrical Conductors in Metals at Low Temperatures;

Reflecting Power of Tungsten and Stellite.

The folloAving new technologic papers were issued : Density and

Thermal Expansion of American Petroleum Oils; Properties of

Calcium Silicates and Calcium Aluminates Occurring in Normal

Portland Cement ; Properties of Some European Plastic Fire Clays

Constitution and Microstructure of Porcelain; Liquid-Measuring

Pumps; Failure of Brass: 1, Microstructure and Initial Stresses in

Wrought Brasses of the Type 60 Per Cent Copper and 40 Per

151
152 KEPOET OF DIRECTOR OF BUREAU OF STANDARDS.

Cent Zinc ; Failure of Brass : 2, Effect of Corrosion on Ductility an'I Strength of Brass; Failure of Brass: 3, Initial Stress Produced by

the " Burning in " of Manganese Bronze ; Manufacture and Properties of Sand-Lime Brick ; Resistance of an Oil to Emulsification ; Recovery of Paraffin and Paper Stock from Waste Paraffin Paper;

Studies on Paper Pulp; Specific Gravity Balance for Gases; Structure of Coating_ on Tinned Sheet Copper in Relation to a Specific

Case of Corrosion; Temperature Measurements in Bessemer and

Open-Hearth Practice; Measurement and Specification of Physical

Factors which Determine Saturation of Certain Tints of Yellow

Glasses for Protecting Eyes from Injurious Radiations; Effusion

Method of Determining Gas Density: Durability of Cement Drain

Tile and Concrete in Alkali Soils; Comparative Tests of Stitches

and Seams.

The following new circulars were issued : Proposed National Electrical Safety Code; Standards for Electric Service; Electric Units

and Standards; Specifications and Tolerances for Weights and

Measures and Weighing and Measuring Devices; Specifications for

and Methods of Testing Soaps; Specification of Transparency of

Paper and Tracing Cloth ; Rules and Regulations for Enforcement of

Lime-Barrel Act; Gas Calorimeter Tables; Standard Samples for

Thermometric Fixed Points.

The following miscellaneous publications were issued : Some Technical Methods of Testing Miscellaneous Supplies; Annual Report

of the Director of the Bureau of Standards for the Fiscal Year ended

June 30, 1916; Eleventh Annual Conference on Weights and Measures of the United States.

Technical Library.

The library contained at the close of the fiscal year 14,929 acces- sioned volumes, all of a scientific and technical character with the

exception of a few law books. Two hundred and ninety-seven scientific and technical periodicals are currently received. This number

does not include 94 (77 of which are German) not received on account

of the war.

Personnel,

During the year the Bureau staff comprised 252 statutory appointees and about 265 engaged in researches and investigations

specially authorized by Congress. The statutory positions included

149 scientific positions, 37 office assistants, 41 engaged in the operation of the plant, and 25 in construction work. There were 778 personnel changes during the year. These included 204 separations

from the Bureau, of which 114 were resignations. There were 219

promotions and 338 appointments during the year,

Appropriation Statements.

The following statement shoAvs the amount and object of each appropriation provided for the Bureau for the fiscal year 1917, the disbursement during the year, the amount of unfilled and unpaid orders

at the close of the year, and the unexpended balance remaining at the

close of business June 30, 1917:
REPORT OF DIRECTOR OF BUREAU OF STANDARDS, 153

Appropriation. Total

appropriation. Disburse- ment. Liability. Balance.

Salaries Equipment

General expenses

Repairs and alterations Grounds

High-potential investigation

Refrigeration constants Testing structural materials Testing machines

Investigation of fire-resisting properties

Public-utility standards Railway materials Testing miscellaneous materials Radio research Color standardization Clay products

Physical constants Standardizing mechanical appliances. .

Testing railroad scales, etc Radio laboratory Chemical laboratory

. Equipping chemical laboratory

Total

$311,720. 00

50,000. 00

28, 500. 00

5,000. 00

6, 000. 00

15, 000. 00

15, 000. 00

100, 000. 00

30, 000. 00

25,000. 00

40, 000. 00

15, 000. 00

20,000. 00

a 14, 459. 71

10, 000. 00

10, 000. 00

5, 000. 00

10,000. 00

40,000. 00 50,000.00

200, 000. 00 35,000.00

S277, 357. 70 33,276.48

19, 104. 30

1, 379. 21

2, 803. 62

13, 822. 86

14, 394. 70

90, 034. 04

25, 254. 75

18, 355. 12

37, 668. 56

12, 660. 74

17, 408. 56 12,511.20 6,661.30

9,212. 13

2, 932. 50

2, 729. 09 31,861.32

1, 334. 76

194, 699. 86

11,385.39

$12,479.11

16, 723. 52

9, 187. 94

3, 387. 03

3,152.93

1, 101. 83

575. 95

9, 815. 03

4,547.03

6, 644. 88

2, 089. 38 2,322.07

2, 512. 88 1,644.81

3,324. 08

787. 87

1, 694. 08

7, 114. 16

8, 138. 68

733. 80

5, 034. 48

23, 473. 68

821,883. 19

1,035,679. 71 836, 848. 19 126,485.22

207. 76

233. 76 43.45

75.31 29.35

150. 93

198. 22

242. 06

17. 19 78.56

303. 70

14.62

373. 42

156. 75

47,931.44

265. 66

140.93

72, 346. 30

o Includes reimbursement of $4,459.71. The following statement shows the condition of the appropriations

for the two preceding fiscal years at the close of business June

30, 1917:

FISCAL YEAR 1915.

Appropriation.

Salaries Equipment

General expenses

Repairs and alterations Grounds , High-potential investigation

Refrigeration constants Testing structural materials Testing machines

Investigation of fire-resisting properties

Public-utility standards Railway materials Testing miscellaneous materials Testing railroad scales, etc

Total

Total appropriation.

$293 o57

27

2

6

15

15 10030

25

25: 1520

4o:

, 500. 00

311.33

000. 00

; 000. 00

, 000. 00

000. 00

; 000. 00 ,000.00

000. 00

;ooo. 00

000. 00

000. 00

000. 00

,000. 00

670, 811. 33

Disburse- ment.

$278, 379. 16

55, 198. 58

25, 965. 04

1,998. .52 5, 998. 74

14,984. 96

14, 997. 89

99, 759. 68

29, 853. 15

24, 650. 37

23,230.31

14,839. 06

19, 920. 64 39,821.07

649,597.17

Liability.

$1,127. 07

364. 00

53. 95

117. 02

1,410. 33

110. 00

100. 08

3, 282. 45

Balance.

815, 120. 84

985. 68

670. 96 1.48

1.26

15.04

2.11 186.37 29.83

349. 63

359. 36

50.94

79.36 78.85

17, 931.71

a Includes reimbursement of $7,311.33. FISCAL YEAR 1916.

Salaries Equipment

General expenses

Repairs and alterations Grounds

High-potential investigation

Refrigeration constants Testing structural materials Testing machines

Investigation of fire-resisting properties. Public-utility standards Railway materials Testing miscellaneous materials Current-meter testing tank

Heating system, north laboratory

Radio research Testing railroad scales, etc

Total

50

27!2

6! 15:

is: loo:

3o:

25:

25: 15

2o:

3:

3, 012;

40,

780. 00

000. 00

000. 00

000. 00

000. 00

000. 00

000. 00

000. 00

000. 00

000. 00

000. 00

000. 00

000. 00

000. 00

000. 00

308. 74

000. 00

687, 088. 74

8283,079. 84

47, 723. 70

26,656. 01 1,985.88

5,901.11

14,799. 92 14,923.23 99,437.16

27,634. 65

24, 879. 78

24, 756. 29 14,427.15

19,999. 96

2, 998. 34

2, 520. 54

12, 140. 49

27, 728. 78

651,592.83

81, 666. 24

263. 20

1.58

152.00

250. 37

2, 264. 51 82.00

3.00

292. 51

12,271.22

17,246. 63

$15, 700. 16

610. 06

80.79

14.12

97. 31

48. 08

76. 77

312. 47

100. 84 38.22

240. 71 280. 34

.04 1.66

479. 46

168. 25

18,249. 28

o Includes reimbursement of 82,308.74.
154 REPOKT OF DIRECTOR OF BUREAU OF STANDARDS.

Summary of Tests.

The work of the Bureau involves, among other things, a large

amount of testing of standards, measuring instruments, and materials. It involves primaril}^ the 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.

During the fiscal year 1917 the Bureau made 155,818 tests and inspected 1,782,044 incandescent lamps at various factories for other

departments of the Government. Of the total tests, 145,939 were for

the Government and 9,909 for the public. The testing was distributed as follows, according to the nature of the tests: Length

measures, 387; mass, 3,746; capacity, 1,189; temperature, 15,763;

hydrometry, 926; miscellaneous, 23; optical, 1,365; time, 69; electrical, 1,290; photometr}^, 2,864; chemical, 13,170; engineering (miscellaneous), 611; engineering (instruments), 482; structural materials, 107,078; paper and textiles, 5.583; metallurgical, 1,402. The

estimated fees amounted to $194,778.14, of which $17,765.47 were

collected on account of tests for the public. The fees noted for

Government tests are included merely for comparison purposes, as no charge is made for tests performed for the National or State

Governments.

Number and Value of Tests Completed, Fiscal Year Ended June 30, 1917.

Nature of test.

For Government. For public. Total.

Number. Value. Number. Value. Number. Value.

197 S491.80 190 S427.95 387 $919. 75 Mass 2,309 27, 554. 85 1,437 606.00 3,746 28, 160.85 Capacity 900 455. 25 289 278. 05 1,189 733. 30 Optical 1,327 1, 980. 50 38 173. 00 1,365 2, 153. 50 Hydrometry 650 681. 15 276 377. 60 926 1,058.75 Miscellaneous 16 60.00 7 8.50 23 68.50 Time 1 100.00 68 322. 50 69 422.50 Temperature 12,850 2, 475. 07 2,913 3, 124. 10 15, 763 5, 599. 17 Electrical 736 3, 684. 77 554 3, 387. 37 1,290 7, 072. 14 2,568 9,411.50 296 625.50 2,864 10,037.00 Chemical >> 10,047 79, 688. 40 3, 123 6, 192. 00 13, 170 85,880.40 Physical and mechanical tests:

" Engineering, miscellaneous 481 1,773.00 30 65.50 511 1, 838. 50 Engineering instruments 421 2, 150. 50 61 400.00 482 2, 550. 50 Structural materials 106, 627 31,281.50 451 1, 359. 90 107, 078 32,641.40 Paper and textiles 5,417 10,880.00 166 313.50 5,583 11,193.50 Metallurgical 1,392 4,344.38 10 104.00 1,402 4, 448. 38

Total 145, 939 177, 012. 67 9,909 17, 765.47 155, 848 194, 778. 14

o In addition, the Bureau inspected 1,782,044 incandescent lamps at various factories for other depart- ments of the Government, the fees for which would amount to 88,910.22 additional.

i> Of these tests, 7,633, amounting to $64,331, were chemical tests made on structiiral materials.

Metric System.

The general use of the metric system in Europe and the need for

supplies and equipment in the metric system has called for a greatly

increased use by American manufacturers. Manufacturers and ex- porters in large numbers have appealed to the Bureau for assistance

and information concerning the metric system and the equivalents.
EEPOET OF DIRECTOR OF BUREAU OF STANDARDS. 155

A large number of charts and circulars have been distributed for

this purpose.

In addition, the movement of the troops to Europe has brought

forth an extended demand for information as to the metric system

for the officers and men in both the Army and Navy. The battleships, cantonments, arsenals, and the various bureaus of the War

Department have been supplied at their request with metric

literature.

A very large distribution of metric system publications has gone

to the public schools of the country at their request. This is

especially large in the case of public schools located in manufacturing districts.

Exhibits of the Activities of the Bureau.

Frequent requests are received from -various organizations for the

Bureau to make exhibits of its activities at expositions or conventions. While it is recognized that such publicity as is thereby given

increases the usefulness to the public of the Bureau work and publications, it has not been possible to comply with all of such requests

owing to lack of funds and personnel available for such work. In

fact, under present war conditions it Avill probabh^ not be feasible to

participate in any such exhibits. However, when normal conditions' are restored, funds should be especially ]3rovided for the proper

preparation and organization of exhibits t3"pical of the activities

of the Bureau, such work to be put on a sure and permanent basis.

The excellent results obtained for past exhibits indicate that a reasonable expenditure will be fuU}^ justified.

Among the exhibits in which the Bureau has participated during

the year are the following: Second Exposition of Chemical Industries, New York, N. Y.. September 25 to 30, 1916; American

Chamber of Cormnerce. Washington, D. C., January 30 to February

2, 1917; American Metric Association, New York, N. Y., December

26 to 28, 1916; Aeronautic Exposition, New York, N. Y., February

8 to 13, 1917; and the Industrial and Export Exposition, Springfield,

Mass., June 23 to 30, 1917. The metric exhibit prepared for the

American Metric Association has been permanently installed in the

American Museum of Natural History.
IV. RECOMMENDATIONS.

Increase in Scientific Staff.

The demands upon the Bureau in connection with the scientific

work of the country, the industries, and especially the military

departments of the Government, have grown by leaps and bounds.

The Bureau is not only neglecting much work that should be done,

but has been compelled to do many things in a temporary and superficial manner. This has been true especially during the past three

years ; nevertheless, every effort has been made to utilize the resources of the Bureau to the greatest possible extent in assisting the public

to meet these new conditions and in aiding the military departments

in the application of science to their problems. The demand on the

part of the industries for accurate and reliable scientific data, a rapidly increasing one, has never been as great nor as important as at present, and such data will be of particular value at the conclusion

of the present war. A conservative estimate for the additional

services needed has been prepared and will be submitted. This estimate has been based solely upon the most urgent and pressing needs

of the Bureau. It is hoped that Congress will recognize the importance of this increase and provide accordingly.

Increases in Salaries.

Never has the demand for scientific and technically trained men

been as great as at present. This has resulted in the loss of many

well-trained men in the Bureau's staff. Tlie time has come when

some of the salaries paid such experts must be increased or their

services dispensed with. This can not be done without a loss in

quality and the deterioration of the high standard of the Bureau's

work.

Additions in the Clerical, Operating, and Construction Staffs.

The clerical staff is entirely inadequate and should be increased

to meet the present urgent needs, which have greatly multiplied on

account of the new demands made upon it. This is true especially

in the care of property', files, records, and correspondence.

The addition of the chemical building, finished a year ago, and

two new buildings now in process of erection, to be completed before

June 30, 1918, n^ake it absolutely necessary to increase the operating

force of the mechanical plant.

The testing and investigational work of the Bureau is greatly

handicapped by the lack of sufficient instrument workers. Estimates

will be submitted for additional assistance of this kind.

Increases in Special Funds.

Increases are urgently needed in several of the special fimds under

which the Bureau is carrying on important work. The structural

material fund is barely sufficient to care for the testing work of the

156
EEPOET OF DIRECTOH OF BUREAU OF STANDARDS. 157

Government service. It should be increased by at least 50 per cent

in order that the Bureau may undertake more investigational work

needed by the Government service and by the public. The importance of this work can hardly be overestimated, not only from the

standpoint of economy and efficiency in the structural work of the

Government, but from that of the efficient and economical use of

these materials on the part of the public and the military services.

The Bureau's work in connection with public utilities has proven

of the utmost importance. The fund available is insufficient to cover more than two or three problems. The present appropriation might

"well be increased several fold; it would meet with the hearty approval of all public-service and municipal bodies having to do with

the regulation of public utilities. It would contribute greatly to

better service on the part of public utilities, as well as to the conservation of life and property.

The enormous annual loss of property by fire emphasizes the great

necessity for a better Imowledge of the fire-resisting pro^Derties of

materials and construction. To be of value such work must be car- ried on with specimens commensurate with those used in practice.

The Bureau's work in this direction has been well organized and

much of the apparatus constructed. However, funds are needed for

additional equipment as well as materials upon which to work, which

in such cases are necessarily expensive; therefore, this fund should

be increased to at least threefold its present value.

An increase is needed in the fund for miscellaneous materials, due

to the growing tendency on the part of the Government to buy such

materials according to properly prepared specifications and tests. During the past year the Bureau submitted an estimate to provide for the determination of physical constants, a part of which

was approved by Congress. These constants are of the utmost value

in scientific and industrial work. Their determination involves the

most difficult work in physics and chemistry. The Bureau should

ever be the source of accurate and authoritative values of this kind

and ample provision should be made for their determination.

The funds available during the coming year for the investigation

of mechanical a^Dpliances are insufficient to meet even the needs of

the Government service alone. This is true especially of the large

number of military appliances and devices that have been submitted

to the Bureau by 'the militar}^ departments. Here again, as in the

purchase of materials, the Government is purchasing machinery and

all sorts of devices in accordance with carefully prepared specifications, and suitable tests are made before their acceptance. The standard of performance in such cases and the methods of measuring the

same are equally important to the manufacturer and to the public.

This fund should be increased to two or three times its present value.

In general, it has been thought best to submit only such estimates

as are urgentlv needed to care for prese:it work rather than to enter

new fields. However, several exceedingly important cases have arisen

for which estimates will be submitted. The work of the Bureau in

connection with the investigation of optical glass has proven of the

utmost importance, both in militarj^ and scientific Avork, and in view

of the necessity for the development of important kinds of glass

which have heretofore been imported, an increase in this special fund

will be submitted.
158 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Estimates will be submitted for work in connection with the following: Standard materials; textiles, paper, leather, and rubber;

electrodeposition metals ; research fellowship ; metallurgical research

chemical reagents; illumination investigation; radio activity; magnetic analysis; insulating investigation; and sea-water concrete investigation. All of these investigations are urgently needed in con- nection with the scientific, industrial, and military development of

the country ; in most cases the results obtained will be applicable to

all of these interests.

Buildings.

Attention is again directed to the urgent necessity of placing the

structural material work of the Bureau in permanent quarters. An

estimate for a suitable site, building, and additional equipment has

several times been submitted and is again presented. It is earnestly

hoped that favorable action will be taken during the coming year.

New^ Refrigerating Machine.

A new machine to produce the refrigeration needed in laboratories

is essential. The present machine was installed in 1904 and was well

suited to the conditions then existing. However, the growth of the

Bureau's work and the addition of new buildings make an increase

of capacity imperative, while these and other conditions indicate

marked economy to be obtained from a motor-driven compression

machine instead of the present absorption type.

S. W. Stratton, Director.

Respectfully,

To Hon. William C. Redfield,

Secretary of Commerce.

o