ANNUAL REPORT

OF THE

DIRECTOR

BUREAU OF STANDARDS

TO THE

SECRETARY OF COMMERCE

FOR THE

FISCAL YEAR ENDED JUNE 30, 1915

WASHINGTON

GOVERNMENT PRINTING OFFICE

1915

ANNUAL REPORT

OF THE

DIRECTOR

BUREAU OF STANDARDS

TO THE

SECRETARY OF COMMERCE

FOR THE

FISCAL YEAR ENDED JUNE 30, 1915

WASHINGTON

GOVERNMENT PRINTING OFFICE

1915

CONTENTS.

Page.

I. Functions, organization, and location 11

1. Standards of measurement 11

2. Pliysical 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 16

8. Organization 17

9. Location ^ 18

II. Scientific and technical divisions 19

1. Weights and measures 19

Weights and balances 19

Capacity and length measures 19

Sieve testing 20

Volumetric glassware 20

Density tables for petroleum oils 20

Barometry 20

Testing of watches 21

Precision and empirical equations 22

Inspecting and testing scales 22

Operation of test-car equipment 23

Condition of track scales 23

Linear expansion of materials 24

Annual conference on weights and measures 25

Tolerances and specifications 25

So-called net-weight amendment to the pure-food law 26

Standard-barrel act 26

Information furnished on subjects pertaining to measures

of length, mass, capacity, and time 26

Publications on weights and measures 27

2. Thermometry, pyrometry, and heat measurements 27

Platinum resistance thermometers 27

A AVheatstone bridge for resistance thermometry 28

A multiple junction thermoelectric thermometer 28

The emergent stem correction for thermometers in creo- sote oil distillation flasks 28

Low-temperature thermometer comparator 29

Specifications for laboratory standard thermometers 29

Recording deep-sea thermometer 30

Other thermometric investigations 30

Characteristics of radiation pyrometers 30

Radiating properties of metals and oxides 31

Other investigations relating to pyrometry 32

Methods of testing refractory materials 32

Standard heat samples 32

Gas calorimetry 33

An aneroid calorimeter 33

Specific heat and heat of fusion of ice 34

Heat capacity of water and the mechanical equivalent

of heat 34

Control of atmospheric humidity in laboratory rooms 34

Constant-temperature room . 35

Thermal conductivities of insulation and building materials ^ 35

Temperature conductivity of cotton bales 36

Tests of household refrigerators 36

Liquid-air plant 36

Industrial viscosimetry 37

3
4 CONTENTS.

II. Scientific and technical divisions—Continued.

2. Tliermometry, pyrometry, and heat measurements—Continued. Page.

Standardization of flash-point testers 37

Refrigeration constants 38

The fire-resisting properties of structural materials 39

Fire tests of building columns 39

Thermal efficiencies of column coverings 40

Strength of steel at high temperatures 40

Thermal expansion of structural materials 41

Panel-testing furnace , 41

Building codes 41

Recommendations concerning fire-resistance investigations 41

Fire tests of insulated slieet-metal cabinets 42

Melting point of concrete ^ 44

Observations in connection with the International Ice Patrol of 1915 44

Testing of heat and tliermometric apparatus 44

Information furnislied, reports, etc 45

New worli and equipment for heat and thermometry 46

3. Electricity 46

Weston standard cell 46

Mercury standard olnn 47

Silver voltameter 47

Inductance of electrical shunts 48

Simple method for testing electrical instrument trans- formers 48

Measurement of earth resistivity 48

Standard air electrical condensers 48

Galvanometers 49

Parallel-decade potentiometer 49

Circular on electric measuring instruments 49

Measurement of conductivity of electrolytes 50

Resistance and inductance of bimetallic wires 50

Magnetic method of determining flaws in steel rails 50

Correlation of magnetic and mechanical properties 50

Magnetic permeameters 51

Temperature coefficient of magnetic permeability 51

Core losses in iron at high inductions 51

Magnetic circular 52

Radium testing 52

Increase in the Bureau's stock of radium 52

Alpha ray activity of uranium oxide powder 52

Radium emanation 52

Circular on radium 52

Radio communication 53

Radio sets for lightliouse tenders 53

Radio interference 53

Promotion of safety at sea 53

Design of inductance coils for radio work 53

Proposed work in radiotelegraphy 54

Additional facilities needed in radiotelegraph work 54

Effect of atmospheric conditions on flame standards of

candlepower 55

Photometry of lights of slight color difference 55

Illuminating engineering 56

Electrical testing 57

Information furnished on electrical subjects 59

Public-utility investigations 60

Service standards for illuminating gas 60

Electric light and power service 61

Cooperation with the Underwriters' Laboratories 62

Electrolysis mitigation 62

Lightning protection 64

National electrical safety code 64

National gas safety code 65

Telepliony 65
CONTENTS, 5

Scientific and technical divisions—Continued.

3. Electricity—Continued. Page.

Relation of the Bureau to municipalities and publicservice commissions 66

Necessity for increasing the public-utility work of the

Bureau 67

4. Optics 68

Determination of standard light wave lengths 68

Information furnished on spectroscopic subjects 69

Investigation of vacuum tubes of the rare gases 69

Quantitative spectroscopic analysis of steel 69

Spectroscopic analysis of an alloy which is liquid at room temperatures 70

Spectroscopic tests 70

Standardization of industrial sugar testing 70

Conference of polarimetric experts 70

Constants of the saccharimeter 70

The specific rotation of pure sugar 71

The rotation dispersion of sucrose (cane sugar) 71

Pure and intense light sources for polarization work 71

Referee work upon molasses testing 72

The optical rotation of dextrose (grape sugar or glucose)- 72

The optical rotation of levulose (fruit sugar) 73

Samples of standard sugars 73

Oven for vacuum work 73

Magnetic field of optical magnet 73

Supervision of the Customs Service laboratories 73

Polarimetric tests of raw sugars and molasses 74

Miscellaneous polarimetric testing 74

Polariscope tubes for sugar testing 74

Color standards and color specification 74

Spectrophotometry 75

Color specification by means of the rotatory dispersion

of quartz 76

Color of cottonseed oil 77

Method of specifying a color limit for oleomargarine 77

Investigation of proposed rosin color standards 78

Establishment of a standard method for testing the trans- parency of tracing cloth 78

Study of method of measuring the turbidity of spinal

fluids 79

Study of the properties of fog at sea 79

Information furnished on optical subjects 79

Investigation of the commonly found errors in photogi-aphic lenses 79

Speeds of photographic shutters 79

Standard lenses for opticians' trial sets 80

Testing optical systems 80

Refractive indices 80

Information furnished as to optical instruments 80

Radiometry 80

Nocturnal radiation measurements 81

Radiometric outfit for physiological work 81

Glasses which are opaque to infra-red rays 81

The Stefan-Boltzmann constant 82

Measurements on the radiation from stars 82

5. Chemistry 82

Standard analyzed samples 82

Chemical tests of an umpire nature 83

Investigation of the methods relating to the analysis of

irons and steels 84

Preparation of iron carbon alloy 84

High-temperature carbon combustions 84

Test of surface combustion furnace 85

Ladle-test ingot investigations 85

Standard methods for the analysis of pig iron and iron

castings for export 85

Standard methods for the analysis of steels 85
6 CONTENTS.

II. Scientific and technical divisions—Continued.

5. Chemistry—Continued. l*age. Tests on steel for other divisions of the Bureau 85

Sampling and analysis of coal 85

Chemical work in connection vs^ith paper 85

Textiles 86

Distinguishing sisal and manila 86

Lubricating and transformer oils 86

Gum arable 86

Articles involving danger to life or property 86

Chemical analysis of rubber 87

Printing ink 87

Determination of oil and resin in varnish 87

Soap 87

Paint investigation 88

Gas analysis 88

Preparation and testing of gases of high purity 89

Control of purity of the Bureau's oxygen supply 90

Colorimetric determination of acetylene 90

Determination of phosphorus and sulphur in calcium car- bide 90

Distillation of liquid air in a magnetic field 90

Preparation of naphthalene 90

Bituminous materials 90

Phosphate rock analysis 91

The chemistry of electrotyping 91

Investigations relating to electroplating 91

Standard cells 92

Chemical work in connection with refrigeration constants- 92

Conductivity of electrolytic standards 93

Platinum investigation 93

Research of the methods and standards employed in volumetric analysis 93

Chemical testing 93

Miscellaneous chemical tests 94

Publications 94

Transfer of the work of the contracts laboratory of the

Bureau of Chemistry to the Bureau of Standards 95

The new chemistry building 95

6. Engineering research and testing 96

Physical equations 96

Aerodynamics ^ 96

Vacuum cleaners 97

Radiator traps used in connection with vacuum systems

of heating 97

Anemometers as speed indicators for aeroplanes 97

Water current meter rating station 97

Gasoline engines 97

Tests of miscellaneous instruments and devices 98

7. Metallurgj' 98

Fusible tin boiler plugs 98

Properties and standard test specimens of bronzes 98

Radiation from metals and oxides 99

The quality of platinum ware 99

Causes of failures of railway materials 300

Causes of failure in car wheels 100

Transverse fissures in rails 101

Finishing temperatures of rails 101

Sound-ingot research 101

Test-ingot investigation 102

Foreign railway specifications 103

Failure of structural brasses 103

Preparation of pure-iron and iron-carbon alloys 104

The iron-carbon equilibrium 104

Determination and distribution of carbon in steels and

irons 104

The physical properties of pure iron and copper 104
CONTENTS. 7

II. Scientific and technical divisions—Continued.

7. Metallurgy—Continued. I'age. Melting points of steels and refractory elements 105

A test of a surface-combustion furnace 105

Nomenclature of nonferrous alloys 105

Investigation of molding sands 105

Pyrometric standard samples 106

Specifications for metals 106

Cooperation with manufacturers on nonferrous metals 106

Metallurgy and chemistry of platinum-group metals 106

Systematic investigation of the properties of metals 106

Aid rendered the public by metallurgical investigations 107

Metallurgical testing 108

Information furnished as to the properties of metals 108

Metallurgical publications 109

8. Structural, engineering, and miscellaneous materials 110

Structural-steel column tests 110

Tests of large columns for long-span bridges 111

Causes of failure of railway materials 111

Standard test specimen for cast bronze 112

Influence of time in testing steel specimens 112

Behavior of spring steel under repeated static and

dynamic stresses 112

Calibration of testing machines 112

Information regarding the strength of metals and their

alloys 112

Tests on the strength of materials 113

Standard specifications for Portland cement 114

Hydraulic cements other than Portland cement 114

Further studies of the hydration of Portland cement 114

Clinkering temperature of the raw mixes used by Port- land cement manufacturers 115

The effect of varying the composition of raw mixes used

in Portland cement manufacture 115

Suitability of various clays, limestones, etc., for making

Portland cement , 116

Investigation and testing of cement, concrete, and stone 116

Durability of concrete in alkali waters 116

Standard cement sieves . 117

Standard fineness sample 117

Effect of fine grinding of Portland cement 117

Granular analysis of cement 117

Stucco and plaster investigation 118

Effect of moisture and temperature changes on concrete- 118

Strength of reinforced-concrete structures 119

Value of the high-pressure steam test of Portland cement- 119

Physical properties of sand cements (silica cements) 119

Value of various materials as concrete aggregate 119

Compressive strength of Portland cement mortars and

concretes 119

Effect of sea water on concrete 120

Fusion of concrete 120

Dusting of concrete floors 120

Investigation of concrete aggregate for Panama Canal 120

Development of an accelerator for hardening concrete 121

Stone investigation 121

Investigation of fire protection for steel columns 121

Investigation of the fire-resisting qualities of partition

and supporting walls 121

The value of tufa rock and volcanic ash as a material

for admixture with Portland cement 122

Investigation of integral waterproofing compounds 122

Roiitine cement inspection and testing 122

Miscellaneous investigations and tests 123

Information furnished as to cement and concrete 123

Publications on cement and concrete 124

The purification of clay 124
8 CONTENTS.

II. Scientific and technical divisions—Continued.

8. Structural, engineering, and miscellaneous materials—Contd. Page.

Porcelain from American raw materials 124

American raw materials replacing the imported glass pot

and crucible clays 124

Mixtures of easily vitrifying and refractory clays with

reference to their rate of vitrification 125

Vitrification of clays and electrical conductivity 125

Softening of porcelain at kiln temperatures 125

Enamels and colors 125

Enameled iron and steel 125

Optical glass 125

Properties of halloysite 125

Silica brick 125

Testing of fire bricks 126

Hollow building tile 126

Experiments on strength of large brick piers 126

Investigation of the resisting power of soils 127

Cooperation with technical societies and institutions 127

Information as to clays and clay products 127

Clay testing 127

Testing of clay products 128

Method of measuring plasticity of lime 128

Improvement of plasticity of hydrated lime 128

Bonding material in sand-lime brick 128

Introduction of carbon dioxide during the stream treat- ment of sand-lime brick 129

Method for estimating the amount of free lime in the

presence of some silicates and aluminates 129

Information about lime and sand-lime brick 129

Temperature of decomposition of gypsum 130

Effect of compression in baling of raw cotton 130

Manufacture of American-grown flax 130

Identification of textile fibers 131

Automobile-tire fabric investigations 131

Adulteration of textile materials 131

Moistiire in cotton fiber 131

Physical properties of spool thread 132

Tensile strength and weight of fabric as influenced by its moisture content 132

Worsted yarn of commerce 132

Comparative tests of cotton and wool flag bunting 132

Scouring of domestic wools 133

Determination of the length of textile yarns of com- merce 133

Methods of testing twine 133

Textile tests 133

Information furnished on textile subjects 134

Publications on textile subjects 135

Investigation of paper for permanent records 135

Influence of atmospheric moisture on printing paper 136

Comparison of various types of paper-testing devices 136

Utilization of old papers for remanufacture into paper 136

Casein and its application to the paper industry 136

Paper testing 137

Information furnished on paper 137

Investigation of lubricating oils 138

Investigation in connection with Government power plants as to quality of lubricating oils 138

Properties of rubber 139

Investigation of rubber hose 139

Kapok flber for life preservers 139

Efficiency of hack-saw blades 140

Investigation and tests of shot lines for the United

States Coast Guard 140

Test of fire hose for use in the District of Columbia 140

Tests of miscellaneous materials 140
CONTENTS. . 9

Page.

III. Office, and engineering and construction 140

1. Office 140

Publications 140

Technical library 141

Personnel 142

Correspondence 142

Storeroom 142

Appropriation statements 142

Statement of tests 143

2. Engineering and construction : 144

Mechanical plant 144

Construction facilities 144

Care of buildings and grounds 144

IV. Recommendations 145

Buildings 145

Transverse testing machine 145

Radio laboratory 145

Salaries and additional assistance 146

Clerical services 146

Skilled and unskilled labor 147

Technical investigations 147

Promotion of export trade 147

REPORT

OF THE

DIRECTOR, BUREAU OF STANDARDS.

Department of Commerce,

Bureau of Standards,

Washington, July 1, 1916.

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

Bureau of Standards for the fiscal year ended June 30, 1915.

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, for the

measurement 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

been 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 with the balance or the methods used. These balances range

from that capable of measuring the thousandth part of a milligram

11
12 EEPOET OF DIEECTOR OF BUEEAU OF STANDAEDS,

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

not only a large number of working standards, all of which must

agree with the fundamental standard, but apparatus suitable for the

comparison of these standards with all of the lengths or weights

found in practice.

These steps and equipment are absolutely essential in order to secure uniform measurements of length or weight throughout the

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

to be measured, whether it be length, weight, temperature, heat,

light, or the various electrical measurements or other standards of

measurement. These standards in one form or another are involved

in practically every scientific investigation, industrial process, engineering structure, or commercial transaction.

2. PHTSICAL CONSTANTS.

There are many fixed relations between physical quantities, the

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

'of scientific work or industry. The amount of heat required to

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

relation between heat and mechanical energy are two important physical constants; their values are used in practically every computation in connection with the designing of steam engines and boilers,

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

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

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

equally important in the refrigerating industries. The value of the

relation between electrical and mechanical energy is involved in

many important commercial transactions concerned in electricity.

Accurate and authoritative values of these constants are just as

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

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

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

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

those not engaged in the scientific or technical work where these

constants are used.

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 by means of the usual standards

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

then arises, Why is it good or poor; what are the physical pr chem-
EEPORT OP DIBECTOR OF BUREAU OF STANDABDS. 13

ical properties or the particular combination of elements which make

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

its constituents determined? These are questions for the laboratory

to answer and involve physical and chemical investigations of the

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

account the purpose for which the material is to be used ; to set the

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

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

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

the Bureau's investigations in connection with the properties of

materials are to enable the user of these materials, first, to select

intelligently the material best suited for the purpose; second, to

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

to make the necessary tests to ascertain whether or not the material

supplied is in accordance with the specifications.

The actual testing of materials by the Bureau of Standards to

ascertain whether or not they comply with specifications is confined

almost exclusively to Government purchases, but . in maldng 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

is even more important to the general public, and is distributed in

the form of suitable publications.

The Bureau does not compete with private testing laboratories,

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

secured in connection with the testing of materials purchased by the

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

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

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

the quality of all things which affect 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 which the

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

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

process upon which the quality of the output depends.

4. STANDARDS OF PERFORMANCE.

The value of an instrument, device, or machine almost always

depends upon the efficiency of its performance. In such cases it

is necessary to state the performance desired or guaranteed in terms
14 REPORT OF DIRECTOR OP BUREAU OP STANDARDS.

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

form of a specification, but specifications are useless unless based

upon correct scientific and mechanical principles and supplemented

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

or not the specifications or guaranties have been complied with.

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

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

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

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

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

those cases where there is a lack of definite information upon 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 with Government

purchases. It has had in this, as well as in the field of the properties

of materials, the most hearty cooperation of the various Government

experts, manufacturers, engineers, and technical societies.

5. STANDARDS OF PRACTICE.

Standards of practice are generally involved in the enactment of

laws when technical and scientific matters are concerned, in the

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

establishment of building and safety codes. Like standards of performance, they are dependent vipon 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 Avork, where National uniformity is desired—fields which can

not be covered efficiently in private laboratories.

6. RELATION OF THE BUREAu's WORK TO THE PUBLIC.

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

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

scientific and technical investigations of the highest grade, involving

the most competent expert services and the best scientific equipment.

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

making the results available and useful to the public.

The 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 enactment of laws, regulations, or ordinances concerning
BEPORT OF DIRECTOR OF BUREAU OF STANDARDS. 15

the weights and measures of everyday trade or in connection 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, of 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 foreign commerce. The use

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

improvement of quality, efficiency, or the development of new 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, while not as extensive as the English institution, is charged

with similar duties. Germany maintains three such institutions

the Normal-Eichungs Kommission, equipped with the buildings,

personnel, and apparatus necessary in standardizing and controlling

the weights and measures of trade; the Physikalisch-Technische
16 REPORT OF DIRECTOR OP BUREAU OP STANDARDS.

Reichsanstalt, covering testing and investigations in connection with

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 BUEEAu'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 Eeclamation 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 i*ealizing 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.
KEPOKT OF DIRECTOR OP 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 have 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 laws 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 radiotelegraphy.

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

with the various electrical standards of measurement, electrical constants, the electrical properties of materials, or the performance of

electrical equipment.

10739°—15 2
18 REPORT OF DIRECTOR 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

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

and the measurement of the optical properties of materials.

Practically all investigations concerning the various classes of

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

many chemical standards and questions which arise in connection

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

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

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

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

functions.

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

been formed dealing more specifically with large and important

classes of materials, but many of the purely scientific questions

involved would be handled by one of the above-mentioned scientific

divisions or jointly with it. The work of the technical divisions is

just as scientific in character, but deals more specifically with manufactured products.

The work of the structural engineering and miscellaneous mateI'ials 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, and 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 Imown 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 Road, near Connecticut Avenue, and are reached by the Chevy Chase car line. It

was 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 inves-
REPORT OP DIRECTOR OP BUREAU OP STANDARDS. 19

tigation, 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.

1. WEIGHTS AND MEASURES.

Weights and Balances.

Investigation of the constancy of analytical weights commonly

used in chemical and physical laboratories have extended over a number of years. It has become increasingly certain that these

weights are much less reliable than is generally assumed. Serious

changes have been noted in many cases where there is known to

have been no special cause for change.

Several high-grade precision balances have been investigated with

special reference to the proper placing and alignment of the knife

edges, and also as to the straightness of the knife edges and bearings.

This preliminary work has given information on which it will be

possible to base more intelligent study of these points with a view to

establishing specifications and more satisfactory methods of testing

these balances. Both makers and users of analytical and other

high-grade balances are greatly in need of standard specifications

and methods of testing these balances.

Plans for equipping the high-precision weighing room secured at the close of the preceding year were partially developed, but could

not be completed because of the pressure of other work.

Of the 3,355 weights tested during the year, 1,884 were for cities,

firms, individuals, etc., and 1,471 were for various branches of the

Federal Government, the State governments, and State institutions.

The large number of tests for State governments show the con- tinued interest in weights and measures inspection. The purchase

by several of additional standards shows the expansion of the State

work. This is especially noticeable in the case of apothecaries' and

metric denominations.

Capacity and Length Measures.

Thei-e were tested during the year 70 capacity measures, including

the standards of several States, and 362 length standards, of which

27 Avere tapes of the nickel-steel alloy. This alloy, because of its low

coefficient of expansion, is being increasingly used for precise sur- veying operations.

An improved method for testing cubic-foot bottles has recently

been developed which is more rapid than the usual method and the

equipment required is less expensive. Instead of using a large and

expensive balance for weighing first the empty bottle and then the

bottles filled with water, use is made of Archimedes' principle in a very simple and comparatively inexpensive piece of apparatus. By

this method one man can test a cubic-foot bottle in about twenty

minutes, whereas the ordinary balance method requires two men

about an hour. It is expected later to apply this method to the testing

of large capacity measures.
20 KEPOKT OF DIEECTOE OF BUEEAU OF STANDARDS.

Sieve Testing.

There were 225 standard sieves or pieces of wire cloth tested during

the year. These inchided, besides the usual 100-mesh and 200-mesh

sieves used in fineness determinations of cement, several sets of

graded sieves for testing other materials. The pieces of wire cloth

included a number of samples of bronze window-screen cloth for use in the Panama Canal Zone, of which measurements were made

to determine whether the mesh and diameter of the wires conformed

with the specifications.

Sieving screens are used in a large number of industries and there

has been a considerable demand for a recognized standard screen

scale in which the screens bear a simple and definite relation to one

another. For the purpose of establishing such a scale, the Bureau

has been making inquiries of the manufacturers using wire sieves

in grading or testing their products to determine the sizes of sieves

most used, with a view to preparing specifications for a scale of

screens which may be suitable for all industries making use of

sieves. A final decision has not as yet been reached in this matter.

Volumetric Glassware.

The glassware tested by the Bureau comprises flasks, cylindrical

graduates, transfer pipettes, measuring pipettes, burettes, and Babcock test bottles. A great deal of this testing is done for various

branches of the Government service. There has been a very considerable falling off in the number of pieces of volumetric glassware

submitted for test during the year, only 1,632 pieces being received;

but the lessening of work on this account has been more than counterbalanced by the 2,306 hydrometers submitted, against 1,213 last

year, and 309 density determinations made, against 109 the previous

year.

Density determinations on samples of sea water were made during

the year in connection with the ice patrol being carried on by the

Government in its safety work on the North Atlantic Ocean. It is

expected that further samples will be collected and their densities

measured at various temperatures, in order to determine the relations

existing between density, temperature, and salinity of sea water.

Density Tables for Petroleum Oils.

Petroleum-oil tables were prepared during the year and will be

published in the form of a circular. The density and expansion of

American petroleum oils obtained from the oil fields of California,

Indiana, Louisiana, Ohio, Oklahoma, Pennsylvania, and Texas were

determined, and form the basis of the tables. These tables, comprising about 100 pages, will be found of great practical value in the

oil trade in various ways, such as in calculating the number of gallons

of oil in large shipments when the quantity is determined by weight

and in ascertaining the quantity of oil in storage tanks.

Barometry.

Apparatus has been constructed and used for calibrating aneroid

barometers at —35° C, the cooling being done by carbon dioxide

and the temperature controlled by lamps and fan in a vacuum

chamber.
REPORT 01* DIRECTOR OP BUREAU OF STANDARDS. 21

Investigations of aneroid, barometers previously conducted by the

Bureau have been confined to the inherent errors of the instruments.

The consideration of secular or of transient errors, being less urgent,

was not taken up for careful study until the present year. Regarding

these latter errors, certain facts have been established by suitable

experiments, (a) concerning the nature of the changes occurring in use and transportation, and the causes giving rise to them; (h) con- cerning the temperature lag of the air, inside the aneroid, or the

time needed for the temperature difference to drop to about one-third

of its initial value, which was found to vary according to the style

of case and degree of circulation of air and from which conclusions

were drawn as to the time necessary in test. It further appears that

transient thermal errors are wholly due to this temperature lag, and

not to local heating.

It has been found by experiment that aneroid barometers may

be successfully compensated against temperature effects at constant

pressure, but still go seriously in error when temperature and pressure

are both changed. Apparatus has been constructed for changing

the temperature and pressure at the same time. The specification of

this error has been reduced to a quantitative basis, and has been

called the temperature coefficient of scale value to distinguish it from

the previously recognized temperature coefficient of reading.

During the year 16 aneroid and 7 mercurial barometers were tested.

Testing of Watches.

The testing of watches for the public, a line of work which was

inaugurated last year, has been continued this year. Three trials,

involving the test of 30 watches, have been held during the year,

each test lasting 54 days.

Watches are divided by the Bureau into two classes according to

the character of the tests, namely, Class A, for watches adjusted to

five positions, and Class B, for watches adjusted to three positions.

A certificate of performance is issued to all watches passing the test. The regulations under which the watch tests are conducted, including criteria and tolerances by which the performance of each

watch is judged, were issued in the form of a circular during the

past year. This circular includes suggestions on the care and

handling of watches, a list of the stations sending out time signals,

and a list of the boundary -points between the various standard time

sections.

In addition to the regTilar test of high-grade watches, the Bureau

has commenced an investigation of stop watches, chronograph

watches, and timers, for registering short intervals of time, principally for the purpose of determining the suitability of various

kinds to the needs of the different branches of the Federal Government. The Bureau is also investigating the relative reliability of

cheaper grade of watches for the purpose of obtaining some definite

information as to rates of watches having fifteen jewels or less, the

degree of isochronism they have, aiid what is the usual accuracy of

their adjustment for isochronism. From these data a definite idea

of the relative merits of watches of different grades will be obtained, a point concerning which very little information is available.
22 REPORT OF DIRECTOR OP BUREAU OF STANDARDS.

Precision and Empirical Equations,

There has long been felt the need of a simple and definite rule for

estimating the precision of the constants of linear empirical equations, since nearly all of the work done by the Bureau in determining the properties of materials and the corrections of measuring

instruments falls under this head. The rules afforded by the

classical texts on least squares have never come into practical use, because they are enormously complicated and not primarily con- cerned with the facts the laboratory wants to ascertain. This need

has been filled by certain formulas which have been devised and

which have proved very useful in the regular work of the Bureau.

Inspecting and Testing Scales.

During the first three months of the last fiscal year 5,000 parcelpost scales for the Post Office Department were inspected at the plant

of the Triner Scale & Manufacturing Co., Chicago. On this contract valuable work was done by the Bureau in improving the general desigTL of the scale and the details of its construction and manufacture. These scales were equipped with approximately 175,000

single counterpoise weights, each of which had to be separately inspected and tested for accuracy before acceptance. It was necessary

to devise special methods of testing in order to make it possible to

test so large a number of weights individually without an inordinate

expenditure of time and effort.

During the year a large number of tests were made on new scales

and scales in service, on the request of the Post Office and other

Federal departments. Especially important was the work of scale

testing done for the Navy Department at the various navy yards on

the eastern coast, detailed recommendations being furnished that

department in relation to the methods to be used in the installation,

operation, maintenance, and test of the numerous scales under its

jurisdiction. A total of 78 scales other than railroad track scales

were tested for this department in connection with the work of the

test car. A number of scales were also tested for the War Department at

Fort Hunt, Va., and Fort Washington, Md.

A sample of an automatic scale and one of a hanging spring-dial

scale, submitted to the Post Office Department for the parcel-post

service by a Chicago contractor, were given a thorough inspection

and test with regard to points of design, and numerous recommendations were made relative to making the scales suitable for vise in the

postal service.

The preliminary study made of the damping of scales resulted in

the discovery of considerable useful data relative to the amount of

friction which will be met in commercial scales and disclosed valuable information relative to the comparative merits of two different

lever systems in the matter of variability and inaccuracy due to

friction.

A careful test and inspection were made, and a full report submitted, on a number of samples of stabilized equal arm trip scales

submitted by a New York City manufacturer, who submitted these

scales to the Bureau with a view to obtaining an opinion on their
EEPORT OF DIRECTOR OF BUREAU OF STANDARDS. 23

design and construction and receiving suggestions as to the methods

which should be employed to improve them.

New drawings were prepared for one of the approved types of

60-pound cast-iron test weights, and of the various forms of approved sealing devices for closing the adjusting cavities of Class C

weights.

A paper was prepared on the subject of automatic scales, and read

before the Tenth Annual Conference on Weights and Measures.

For the purposes of this paper, information was compiled in large

amount in relation to the various types of automatic scales on the

market, and drawings and literature of every sort were procured

and placed on file for reference on this important subject.

In connection with the same paper, a study was made of the cam

and pendulum construction used in the more usual types of automatic scales, and useful analytical and graphical methods were

devised for the design of the cams used in these scales. This is

work of very great importance to the manufacturer and should be developed more fully, as the amount of exact information available

to the designer of this apparatus is very meager.

The Bureau acquired during the year a large platform scale of

10,000 pounds capacity, mainly for the purpose of checking its

own standards of this denomination, which form a part of the railroad track scale testing equipment of the Bureau. This has temporarily been installed in the engineering shop in order that the crane forming a part of the equipment in that shop might be used to

handle the large masses involved. It is doubtful, however, whether

the floor of the shop is sufficiently strong to carry the additional

weight involved in the test of such large masses, and it is urgently

recommended that a special laboratory with a suitable crane and

foundation be provided for the test of heavy weights, for which

there is an increasing demand. Such a laboratory would also afford

facilities now lacking and badly needed for erecting and testing

large scales and provide much-needed room for the scale-inspection

work of the Bureau.

Operation of Test-Car Equipment.

The equipment for testing railroad track scales, purchased in

1913, has been in continuous service during the year, with the ex- ception of a period of about one month, when it was withdrawn in

order to make necessary repairs. Subsequent to the test and standardization of a master scale for the State of Minnesota, in July,

1914, 338 railroad-track scales in the States of Minnesota, Wisconsin, Indiana, Iowa, Missouri, West Virginia, Virginia, North Carolina, South Carolina, Georgia, Florida, Alabama, and the District

of Columbia; and 78 scales other than railroad-track scales, in the

navy yards at Norfolk, Va., Charleston, S. C, Key West, Fla., and

Pensacola, Fla., were tested. These scales were located in 86 different cities or towns, and of the track scales 241 were owned by

railroads, 89 by manufacturing concerns, and 8 by the Federal Government.

Condition of Track Scales.

Of the 338 track scales tested, 107, or about 32 per cent, passed

and 231, or 68 per cent, failed to pass the tolerance adopted by this
24 KEPOKT OF DIEECTOR OF BUREAU OF STANDARDS.

Bureau, which allows a maximum possible error of 200 pounds in

weighing a car of 100,000 pounds. The magnitude of the possible errors of weighing a 100,000-pound car were found to vary in commercial scales from 30 pounds to 21,600 pounds.

Reports giving the condition of the scales tested have been ren- dered to the States which have organized departments of weights

and measures. They have also been rendered to the owners of scales

when such reports were requested, in which were given the condition

of the scale and advice relative to the proper maintenance and repair

of the scale. These individual reports, beginning June 1, 1915, were

sent to the owners whether they were requested or not. The acknowledgments of these reports show that the work is appreciated and that

frequently repairs and new installations follow as a result.

Progress has been made in developing improved methods of test- ing and adjusting track scales, and considerable work has been done

relative to the establishment of a standard method of determining

their capacity. Several scales were examined and their capacity

determined for State departments, but it was found necessary to

limit this work to a very small amount, owing to the smallness of

the force.

Specifications were prepared for the use of the National Zoological

Park in the purchase of auto truck scales. Some progress has been

made in the preparation of railroad-track scale specifications which

will be of value to scale manufacturers, purchasers, and users. An effort has been made to serve as many States and as large a

territory as possible with the equipment available, but with 21 States

visited to date since October, 1913, it is apparent that more than the

present car and. the one soon available will be needed in order to

carry out even a small part of the work. An additional office force

will also be required to handle the results of the track-scale tests and perform the work in the numerous other fields, such as grain

weighing, at present awaiting development.

Linear Expansion of Materials.

During the year the range of temperature available for measure- ments of thermal expansion, electrical resistance, and magnetic

permeability in the oil bath regularly used to over 300° C. was

extended downward to a temperature of —40° C.

Improvements have been made in the electric furnace used for

heating uniformly specimens under test for thermal expansion.

Specimens need no longer be limited to the single length of 30 cm. and a diameter of from 5 to 10 mm. ; the furnace is now capable of

receiving specimens having any multiple of 5 cm. up to 30 cm. in

length, and almost any cross section, not necessarily uniform, up to

2 or 3 cm. The simultaneous measurements of thermal expansion and electrical resistivity, which were commenced a little over a year ago, are progressing favorably and data are gradually accumulating.

An investigation has been started to obtain new data on the thermal expansivity of fused silica (quartz glass) throughout a wide

temperature interval, and to compare the expansivities of various

specimens prepared under different conditions. There has been ac- quired by the Bureau a set of 20 specimens, especially prepared for
EEPOBT OF DIEECTOE OF BUEEAU OF STANDAElDS. 25

this investigation, and representing in duplicate the five types of

products, both annealed and unannealed, made by the donor of the

specimens. Since fused silica has already become a sort of international standard for thermal expansion, it is important to know the

nature and extent of variations in the expansivity of specimens from

various sources and subjected to various treatments. It has a wide

range of commercial uses, on account of its small expansivity and its

resistance to the action of many chemicals. The investigation now

in progress is likely to explain why certain types of the product give

better results than others,

A study of the expansivity of nickel steel has been commenced for

the purpose of assisting American manufacturers in developing

methods for producing nickel steels of specified thermal expansivity

combined with stability-of dimensions and other desirable properties.

At the present time practically all nickel steel for scientific purposes

is imported from Europe.

Experiments on the expansion of structural steel and the elastic

properties and strength of materials at high temperatures have been

iindertaken in connection with the investigation of fire-resisting

materials being conducted by the Bureau. Studies will be carried

out on the expansion of specimens selected from different parts of

typical steel shapes, in order to determine the change in length on

first heating steel beams or columns to high temperatures, and to as- certain whether this expansion is xmiform or not throughout the section. These investigations are to obtain data much needed by engi- neers for designing structures that may be subjected to temperatures

above the ordinary atmospheric range.

Annual Conference on Weights and Measures.

The Tenth Annual Conference on Weights and Measures was held

May 25-28, 1915, at which there were present 28 delegates representing 18 States, the District of Columbia, and the Philippine Islands;

69 city and county weights and measures officials; and about 80

visitors, representing railroads, manufacturers of weighing and measuring apparatus, trade bodies, etc. The purpose of the conference is to bring together State and local

weights and measures officials to discuss administrative and technical

problems which arise in the work. It also serves to point out the

great financial saving to the public in having State supervision and

local inspection of all weights and measures in commercial use. When it is considered that within the decade that these conferences

have been taking place about two-thirds of the States have undertaken this work and vast improvement is reported from practically

all sections of the country, it may be presumed that the conference is' having marked success in this important economic work.

Tolerances and Specifications.

One of the most important accomplishments of the Annual Conference on Weights and Measures, from an administrative point of

view, is the adoption of tolerances and specifications for weights and

measures and weighing and measuring devices. The necessity for

uniform tolerances and specifications is a pressing need, on account

of the vast interstate commerce carried on in the United States, and
26 EEPORT OF DIRECTOR OF BUREAU OF STANDARDS.

it is believed that those adopted at the last conference will meet this

need, which is felt by all weights and measures officials. Heretofore

there have been no regulations of this character recognized by the

various States.

So-Called Net-Weight Amendment to the Pure-Food Law.

In the amendment of March 3, 1913, to the National Food and

Drugs Act of June 30, 1906, provision is made with regard to food

in package form for the establishment by rules and regulations of

reasonable variations and tolerances, and also exemptions as to small

packages. This Bureau is cooperating with the Bureau of Chemistry

of the Department of Agriculture in the collection and analysis of

data on the weight and methods of packing food put in package form,

with a view to establishing tolerances and variations provided for in

the law. This investigation has been going on for a number of

months and satisfactory progress is being made.

Standard-Barrel Act.

An act establishing a standard barrel was passed by Congress last

winter and approved March 4, 1915. This act, known as the " standard-barrel law," fixes a standard barrel for fruits, vegetables, and

other dry commodities, and certain subdivisions thereof, and a standard barrel for cranberries. This act refers both to interstate and intrastate transactions and is the first mandatory standard for general

commercial use ever established by Congress under the power given

to that body by the Constitution " to fix the standard of weights and

measures." It is expected that this will be of great help to manufacturers, shippers, commission men, and consumers, since for the

first time the term " barrel " will have a definite and certain meaning

in the United States. Eeasonable variations from the standard are permitted and the Bureau of Standards is empowered to establish

tolerances and rules and regulations for the enforcement of the act. Efforts to obtain uniform weights and measures laws among the

States have continued to receive the earnest support of the Bureau,

and have met with gratifying success during the past year. Among

the States to which assistance was rendered by this Bureau and in

Avhich satisfactory legislation was passed may be mentioned Oklahoma, Oregon, West Virginia, Utah, Minnesota, and California.

Information Furnished on Subjects Pertaining to Measures of

Length, Mass, Capacity, and Time.

Information concerning screw threads has been furnished in an- swer to numerous inquiries with regard to the correct figures for,

and the use of, various screw-thread systems, wire, and sheet-metal

gages. Among the tests made was one on the determination of the

variation in pitch of a screw and the standardization of a bar, both

to be used in a comparator for the verification of the accuracy of the

standard gages, limit gages, etc., made by a well-known manufacturer of machine and mechanical specialties.

The Bui-eau has kept in touch with the work of the committee on

tolerances in screw-thread fits of the American Society of Mechanical

Engineers, and was represented at several meetings of the committee.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 27

There has been an increasing demand for information as to instruments and methods for measuring the humidity of the atmosphere. A large number of letters have been written and a number

of psychrometer charts have been prepared and sent out.

As an example of the value of the Bureau's work on the density

and thermal expansion of petroleum oils, it may be stated that the

rate of expansion of a sample of fuel oil was measured for a railroad company in order to determine whether the temperat tire cor- rection factor for specific gravity should be 0.0004 or 0.0005 per degree Fahrenheit. It was stated by the railroad company that this

difference in expansion meant a gain or a loss to them of between

2,000 and 3,000 barrels of oil per month on a single contract.

Information, specifications, and blueprints for the construction of

bench standards for the comparison of steel tapes have been furnished

two organizations planning to construct such standards.

The Bureau receives a large number of letters from weights and

measures officials throughout the country asking for information and

advice concerning their work. It is the aim of the Bureau to assist

these officials in every way possible, and to cooperate with them in

their work.

Publications on Weights and Measures.

There have been published during the year the report of the

Ninth Annual Conference on Weights and Measures; Circular No.

51, Measurement of Time and Test of Timepieces; and Circular

No. 47, Units of Weight and Measure.

A paper covering the barometry investigations of the Bureau has

been practically completed for publication in the Bulletin of the

Bureau. It presents concisely and without experimental details the

final and practical results of the various barometry investigations

conducted by the Bureau.

2. THERMOMETRT, PYROMETRT, AND HEAT MEASUREMENTS.

Platinum Resistance Thermometers.

The construction of 11 platinum resistance thermometers has been

completed. These thermometers, which involved the most painstaking workmanship, are designed for measuring temperatures with

the highest attainable accuracj'^ from —200° C. to about 600° C,

and when standardized will serve as the instruments for reproducing

the standard scale of temperature of the Bureau. The instruments

designed for low temperatures are provided with means for drying

the air within the thermometers to prevent the condensation of

moisture on the coil and leads. The instruments designed for measuring small temperature changes of a few degrees with an accuracy

of a few ten-thousandths of a degree, besides being provided with

drying heads, are inclosed in closely fitting platinum cases from

which the coil is insulated by the thinnest sheet of mica, so that the

thermometer coil will follow rapidly vax-ying temperatures with the

minimum of lag. This t^'pe of thermometer, which was developed

by the Bureau and which has been described in Scientific Paper

No. 200, is finding extensive use in engineering and research laboratories. The high-temperature thermometers are mounted in ex- ternally glazed porcelain tubes. All of the thermometers are con-
KEPOEO:' OF DIRECTOR OF BtlREAU OF STAlSTDARDS.

structed so that variable lead resistance can be eliminated, and stray

electromotive forces are reduced to a minimum. On account of its

high electrical conductivity, resistance to oxidizing influences, and

small thermoelectromotive force against platinum and copper, the

thermometers are provided with gold lead-wires, with the exception

of the calorimetric type, which have the usual flat copper leads to

the platinum coil.

A Wheatstone Bridge for Resistance Thermometry.

The highest accuracy attainable in the measurement of small temperature intervals met with in calorimetry with the most carefiilly

standardized thermometers of the mercurial type is of the order of

0?002or 0?003 C. When higher accuracy is required, use must be

made of electrical thermometers of the resistance or thermoelectric

types, used in connection with a suitable resistance bridge or potentiometer. The present bridge was especially designed for the re- quirements of the Bureau in calorimetric work of the highest ac- curacy. Special features are mercury contact links, the use of shunt

dials for the 0.0001, 0.001, and 0.01 ohm decades, a new form of

hermetically sealed coil, and complete oil immersion of contacts as well as coils in order to reduce disturbing thermoelectromotive forces.

Measurements by the Thomson double-bridge method are also provided for. A complete description of this bridge has been published

in Scientific Paper No. 241.

As a result of the experience gained with the use of this apparatus, a simplified type of bridge adapted to resistance thermometry

has been designed and constructed and has been in use for a year or more. This will be described in a future number of the Bulletin of

the Bureau.

A Multiple Junction Thermoelectric Thermometer.

A multiple junction thermocouple, made by the Geophysical Laboratory and kindly loaned to the Bureau, was standardized by comparison with a platinum resistance thermometer to an accuracy of

0?001 orO?002 in the range 0° to 50° C. This multiple thermocouple

has been used by the above laboratory to standardize a number of

their couples and it thus serves to define the temperature scale for

the precision work of that laboratory in the range 0° to 50° C.

The Emergent Stem Correction for Thermorneters in Creosote Oil

Distillation Flasks.

Thermometers used in distillation flasks are subject to error if a portion of the thermometer stem, containing the mercury column, is emergent from the flask and is at a temperature different from that

of the bulb.

This emergent stem correction error is discussed with particular

reference to creosote oil distillation. Emergent stem corrections were

determined, applicable to a particular type of thermometer when

usedjn four types of distillation flasks.

Tne average correction found for the ordinary side-neck distillation flask at 200° C. was 4?5; at 250°, 6?0; at 300°, 10?5; and at 350°, 15?5, with differences of as much as a degree between the same
REPOBT OF DIBECTOR OF BUREAU OF STANDARDS. 29

readings on different runs, making it evident that the average cor- rections could not be relied upon to better than a degree. For the

same temperature, using the same thermometer in different flasks,

the greatest difference in the stem corrections found was 2° C.

Eeasons for variations in emergent stem corrections for different runs on the same flask are discussed. The greatest errors are caused

by the use of unsuitable thermometers and variations in the rate of

rise of temperature. The most suitable thermometer for distillation

flasks seems to be a continuous-scale graduated stem type of mercurial

thermometer having a length of about 40 cm. The effect of radiation and condensed vapor on the temperature

measurement is discussed.

The magnitude of the disagreement in distillation results when in one case allowance is made for stem correction and in another case

it is not, is shown by example.

A method was suggested by which the total correction (including

scale correction and emergent stem correction) to a thermometer used

in distillation flasks can be determined at two points by reading the

thermometer first in the vapor of boiling naphthalene (temperature

218° C.) and then in the vapor of boiling anthracene (temperature

340° C). Interpolations for the corrections betAveen these two points can then be made. This method was investigated and found to be

reliable to 1° or 2°. This investigation has been published under the

above title in Technologic Paper No. 49.

Low-Temperature Thermometer Comparator.

A low-temperature comparator was designed and built. It consists of a large cylindrical Dewar flask containing a suitable liquid

(gasoline or pentane) and is provided with a motor-driven stirrer.

Cooling to —60° C. is effected by expanding (through a sensitive valve

and an immersed coil) carbon dioxide obtained from the CO, compression system maintained at the Bureau. Below —50° C. liquid

air supplied through a siphon in the required quantity is used and

temperatures down to —150° may be obtained. An electric heating

coil in the bath is used to aid in temperature regulation. An investigation of the temperature distribution in the bath has shown that

at —50° the temperature over a length of about 25 cm. is uniform to

0?01 or 0?2C.

Specifications for Laboratory Standard Thermometers.

Some time has been given to the preparation of specifications for

high-grade laboratory thermometers of a type suitable for working

standards in the laboratories of the Bureau and in other scientific

and technical laboratories. After the thermometers made up in ac- cordance with these specifications have been thoroughly tried out

and the specifications have been finally revised in the light of the

experience resulting therefrom, it is planned to publish a circular

on specifications for laboratory standard thermometers. Such a circular would answer numerous inquiries addressed to the Bureau^ on

this subject and would be of great service to many scientific and

technical laboratories in furnishing information as to the equipment

of the laboratory with reliable working standards.
30 REPOET OF DIKECTOR OF BUREAU OF STANDARDS.

Recording Deep-Sea Thermometer.

At the request of one of the Government bureaus, designs were

prepai'ed for a deep-sea thermometer which would give a continu- ous record of deep-sea temperatures with an accuracy much greater

than is attainable with the ordinary reversing type of mercurial

thermometer, an accuracy of 0?01 being desired. The principle

adopted is similar to that of the mercurial thermostat, except that

the platinum contact point is movable. This contact point, mounted

on the lower end of a steel rod (0.5 mm.), is driven downward

through the bore of the capillary by clockwork mechanism until the

platinum point comes into contact with the mercury meniscus, when

an electric circuit is closed, the rod lifted upward a short distance,

after which it again proceeds downward as before. The upper end

of the rod carries a point which marks a continuous line on a roll

of paraffined paper, a scale being simultaneously recorded by similar means. The whole mechanism is inclosed in a steel cylinder (40 cm. high by 12 cm. diameter) capable of resisting deep-sea pressures.

An opportunity has not yet been found for constructing and trying

out this design.

Other Thermometric Investigations.

Owing to the very great demands on the thermometric section for

testing, it has been possible to give but little time to several investigations that have an important bearing on the work of this section.

There has been a considerable demand both from other laboratories of the Bureau and from outside laboratories for thermocouples

standardized at very low temperatures (—200° C). A stock of

special wires for this purpose was purchased some time ago and it would be of great advantage to the Bureau to standardize these

wires so that they could be issued for use for low-temperature measurements. It is hoped that the necessary assistance can be given to

this section so that the important work of establishing the low-temperature scale can be taken up and completed in the near future.

Some progress is reported on the following investigations:

The standardization of the specially designed and constructed

platinum resistance thermometers described in the earlier sections

of this report.

The determination of the " ice-point depressions " of different

thermometric glasses after heating and of the rate of recovery of

the same. The standardization of a complete set of mercurial thermometers

for use as working standards in the interval —40° to 500° C. The

completion of this investigation is essential to the work of testing.

Characteristics of Radiation Pyrometers.

Kadiation pyrometers are instruments in which the measurement

of the temperature of a body is based on the measurement of the intensity of the radiation (both light and heat) emitted by that body.

The object of these present investigations has been twofold—(1) to

assist the pyrometer manufacturer in producing a more reliable and

satisfactory instrument and (2) to call attention to the possibilities

of the instrument, and the precautions which must be understood by

technical and scientific men who employ this method of temperature
REPOBT OF DIRECTOR OF BUREAU OF STANDARDS. 31

measurement. Full details of this investigation have been published

in Scientific Paper No. 250. The paper treats in detail the following

subjects

:

1. General principles of radiation pyrometry, fundamental equations, and mechanical requirements which must be considered in the

construction of the instrument.

2. Types of radiation pyrometers. The construction of the various

pyrometers available is discussed, and the principles upon which

many of the working parts operate are considered.

3. Methods of calibration. Tavo methods are given, one a primary

method in which the calibration is obtained by sighting the pyrometer

into an opening in a uniformly heated inclosure, known as a " black

body," the temperature of which can be measured by thermocouples.

The other method is a secondary method which may be used to calibrate other pyrometers by comparison with a standard pyrometer

calibrated by the first method.

4. Method of use. Under this heading are considered methods of

obtaining the reading of the pyrometer, extrapolation of the temperature scale to higher temperatures than those at which a calibration can be made, methods of automatically recording which permit a continuous automatically printed record of the temperature of a furnace during a prolonged run, as well as a check upon the operators

of the furnace. These records are very valuable in the technical industries. Radiation pyrometers in general require a rather large source upon which the pyrometer is sighted. Methods are given for

obtaining the correct temperature when the source is of insufficient

size to meet this requirement.

5. Discussion of errors. The elimination of the errors in measure- ments with radiation pyrometers is of great importance. These

errors are considered in detail for every type of instrument. If the

precautions given are strictly followed, the temperature measvirements can be relied upon. If these precautions are not followed,

errors may be involved of such magnitude that in general the readings of the instrument will be of no value whatever.

6. Applications. The use of the radiation pyrometer for the study

of the radiating properties of glowing materials is considered, and

data are given for correcting the readings of radiation pyrometers,

sighted upon several metals and oxides in the open, to true temperatures.

Radiating Properties of Metals and Oxides.

An important factor in recent metallurgical progress in the development of special alloys is the better control of temperatures that

is now possible.

In many of- these processes the temperature must be measured by

optical or radiation pyrometers. These pyrometers read incorrectly

when sighted upon glowing metals in the open. It has been the

purpose of this investigation to determine the corrections neces- sary to apply to the pyrometer readings to obtain the correct temperature of the material sighted upon. The investigation of nickel

oxide was reported last year. The paper has since been published

as Scientific Paper No. 224. Partly from the purely scientific interest, the radiation of platinum has been studied and a theory has been
32 REPORT OF DIRECTOR OF BUREAU OF STANDARDS,

developed connecting the total radiation with the resistance and

temperature of a metal. This work was published in Scientific

Paper No. 243. The fourth number in this series, Scientific Paper

No. 249, is an investigation of the radiometric properties of iron

oxide. Corrections are given which permit the measurement of the

true temperature of a steel rail; for example, as it passes through

the rolls. The temperature gradient through the layer of oxide

formed upon glowing iron in the open air was also measured. The

outside oxide layer on a glowing iron rail may be 100° cooler than

the iron immediately under the oxide.

In the coming year these investigations will be extended to other

metals and oxides.

Other Investigations Relating to Pyrometry.

Some time has been given to the preparation of papers on " The

Center of Gravity and the Effective Wave Length of Transmission

of Pyrometer Color Screens " and on "A New Relation Derived from

Planck's Law," which will be completed and submitted for publication eai-ly in the next fiscal year.

Methods of Testing Refractory Materials.

The Bureau is cooperating with the Amrerican Society for Testing

Materials in a study of the methods of testing materials used to withstand high temperatures. Methods of determining the following

properties are being studied : Melting point ; chemical composition

;

thermal conductivity; thermal expansion; porosity; permanent volume change ; crushing strength at ordinary and at high temperatures

;

resistance to abrasion; resistance to spalling; resistance to slagging

action.

Any experimental work that may be required will be done in one

or the other of the laboratories of the Bureau equipped for the work

in question.

Standard Heat Samples.

In the last annual report was described the determination of the

heats of combustion of specially purified samples of cane sugar,

benzoic acid, and naphthalene. This work has since been published

in Scientific Paper No. 230. Samples of these substances are now

regularly sent out by the Bureai; as standard heat samples and are widely used by chemists and engineers for the standardization of the

calorimeters used for testing the heat values of fuels, foods, etc. Two hundred and fifty-three of these standard heat samples were

furnished during the year to numerous industrial plants using large

supplies of fuel, such as cement, steel, cotton, and paper mills ; coal,

oil, and gas companies; electric power companies; and chemical

manufacturing plants ; as well as to university, technical, municipal,

State, and National testing laboratories and bureaus.

As time permitted, determinations have been made of the heats

of combustion of other substances, such as hippuric acid, anthracene,

camphor, phthalic acid, pthalic anhydride, and salicylic acid. The

samples on which these determinations were made were prepared

several years ago. The determinations should be repeated on more

recently purified samples before the results are ready for publication.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 33

Another calorimeter jacket, very similar to that used in the investigation above referred to, has been constructed by the instrument

shops of the Bureau, and detailed working drawings have been furnished to a manufacturer who contemplates putting it on the market

so that it will be available to laboratories requiring the highest

accuracy in calorimetric measurements.

A new edition has been issued of Circular No. 11, entitled "The

Standardization of Bomb Calorimeters." This circular contains

more complete information on the use of the standard heat samples

for the standardization of bomb calorimeters than was contained in

the previous edition. The most important feature of the circular,

however, is the change in the standard heat unit of the Bureau,

effective July 1, 1915, to which change attention is directed. After

careful consideration the Bureau has decided to adopt as the fundamental unit of heat the calorie, expressed in terms of the capacity

for heat of water at 20° C., instead of at 15° C, as heretofore.

Gas Calorimetry.

The publication of Technologic Paper No. 36, on " Industrial Gas

Calorimetry," and of Circular No. 48, on " Standard Methods of Gas

Testing," both of which were reviewed in last year's report, has

resulted in greatly increasing the demands on the Bureau for the

testing of gas calorimeters, the work in this section being several

months in arrears. A member of this division together with a member of the chemical

division were called on as referees to investigate the differences in

the results of heating value tests found in a large eastern city by the

engineers of the State ]Dublic-service commission and by the engineers

of the public utility supplying the gas.

An investigation that has been carried forward from year to year

is one relating to the determination of the heating value of the more

important elementary gases that enter into the composition of natural

and manufactured gases. Some progress can be reported this year

by the chemical division in the preparation of very pure hydrogen

for this work and by this division in a number of determinations of

the heat of combustion of samples of this hydrogen. It is to be

hoped that the necessary assistance can be given to this section to

take care of the increasing demands for testing, so that greater

progress will be possible on this important investigation.

An Aneroid Calorimeter.

For the measurement of specific heats and latent heats of substances imder pressure (for example, anhydrous ammonia, carbon

dioxide, etc.) and for other purposes outside of the range of application of the familiar form of liquid calorimeter, there was developed

a calorimeter which utilizes for equalization of temperature the

thermal conductivity of a solid copper shell in connection with a

built-in heating coil and a built-in platinum resistance thermometer.

Details of the design, construction, and operation are described in

Scientific Paper No. 247. Results of the standardization of the

instrument are given, and also, as the results of a test of its performance, a few experimental determinations of the specific heat of water

in the interval from 0° C. to +40° C. The precision attained was

10739°—15 3
34 EEPOET OF DIRECTOE OP BUEEAU OF STANDAEDS.

such _ as to indicate an entirely satisfactory performance of the

calorimeter. The results of these determinations are in fair agreement with the mean of a number of the more reliable measurements

in recent years, but must not be considered as an authoritative

measurement by the Bureau of this very important quantity.

Specific Heat and Heat of Fusion of Ice. As a part of the program outlined later under the title " Refrigeration constants" there were completed a series of experimental determinations of the specific heat of ice in the temperature range

from —40° to 0° C. and of the heat of fusion of ice. The measure- ments were made by means of the calorimeter of aneroid type described above.

The specific heat of four samples of ice, all of high but of different

degrees of purity, was determined. By analysis of the results the

conclusion drawn is that (s) the specific heat of pure ice, may be

represented between —40° and —2° by the equation s=0.56574-

O.OOI863G, the unit being the 20° calorie, and 6 being the Centigrade

temperature. Between —2° and —0?05 the specific heat does not

exceed the value given by this equation by more than 0.004/6^. The

specific heat of impure ice, within the same temperature interval,

was found to be greater than that of pure ice by an amount 80 1 /G^,

where 1 is the (centigrade) freezing temperatui-e of the ice. The

value found for the latent heat of fusion of ice is 79.76 20° calories

per gram, which is within 1 part in 4,000 of the value determined

last year by an entirely different method. The results are communicated in Scientific Paper No. 248.

Heat Capacity .of Water and the Mechanical Equivalent of Heat.

No progress has been possible on this investigation during the past

year.

This investigation is of fundamental importance in fixing the primary unit of heat. In the half dozen or more extended pieces of

work that have been published on this subject, which may be said

to be more or less generally accepted, there appear startling discrepancies, and it is evident that this fundamental measurement has

not been made with anything like the degree of accuracy which

modern calorimetric practice demands. In the course of the calorimetric researches that have been under way in the laboratories of the

Bureau during the past several years, a great deal of valuable data

have been obtained on the capacity for heat of water. The work has

suggested improvements in apparatus and in methods of experimentation which will be tried out as soon as opportunity permits. In view

of the importance of the work and of the discrepancies in existing

data, it is deemed best to withhold publication until the work has

been carried out with the highest accuracy that can be obtained by

the best modern methods.

Control of Atmospheric Humidity in Laboratory Rooms.

In many technical and scientific laboratories the effects of atmospheric humidity are such that it becomes of importance to maintain constant conditions not alone as to temperature but as to
BEPOET OF DIRECTOR OF BUREAU OF STANDARDS. 35

humidity as well. Examples of such, laboratories are certain customs

and textile laboratories and electrical laboratories. This division has

been cooperating with some of the other divisions in a study of

feasible methods of controlling atmospheric humidities in laboratory rooms.

Constant Temperature Room.

One of the laboratory rooms was rebuilt during the year as a special constant temperature room for the thermal conductivity measurements. The walls were well insulated and a special cooling and

heating system with automatic control installed, so as to maintain

any temperature from that of freezing water to as hot as an observer

working in the room can stand. The room was designed especially

for service tests of pipe coverings, which series of tests can be started

as soon as observers may be available to assign to it. Thermal Conductivities of Insulation and Building Materials.

This work has been undertaken at the request of the railway companies in connection with insulation requirements of steel passengercar construction, and the Railway-Mail Division of the Post Office

Department, in connection with insulation specifications for steel

postal cars; the manufacturers- of building insulation materials,

steam and brine pipe coverings, etc. ; the furnace construction industry; and the furniture construction and refrigeration industries,

in connection with the construction of cold rooms and refrigerators.

Thermal conductivity data are also of importance in connection with

building construction in its bearing on the heating of buildings, the

resistance of walls, floors, etc., to the flow of heat and transmission of fires, the effectiveness of fireproof coverings of columns,

girders, etc. Notwithstanding the fact that thousands of thermal conductivity

measurements have been made in many different laboratories, the

results are extremely unsatisfactory, showing wide discrei^ancies.

The need of standardization is obvious, but the problem presents unusual difficulties and the progress of the investigation is necessarily

slow.

A piece of trial apparatus, taking samples in the form of slabs

about 8 inches square, has been in satisfactory service for some

months, and a similar apparatus for much lai-ger samples has been

constructed and used to some extent. Preliminary reports of the

work have been submitted for criticism and consultation to the

manufacturers who furnished samples. Especial attention is beinggiven to the investigation of the factors which determine the insulating properties of an air space, such as thickness of air layer,

distance between baffle plates to break convection streams, etc. A

proper understanding of these factors will have an important bearing on the cellular wall construction of cold rooms, refrigerator cars, and car insulation in general.

Some time has been given to the design of an apparatus adapted

to the determination of the thermal conductivities of materials up

to temperatures corresponding to red heat, as well as at ordinary

temperatures.
36 KEPOET OF DIEECTOE, OF BUEEAU OF STANDARDS.

Temperature Conductivity of Cotton Bales.

For the purpose of determining the feasibility of destroying by

heat a particukxr boll weevil found to be present in bales of imported

Egyptian cotton, the Bureau of Entomology of the Department of

Agriculture requested this Bureau to determine the time required to

bring all points in the interior of a bale of cotton to a certain minimum temperature, when the exterior was maintained at a higher

known temjDerature.

To this end copper-constantah thermocouples were placed, with

considerable difficulty and labor, at various points in the interior of

the bale, the bale placed in a specially thermostated constant temperature room maintained at approximately 150° F., and readings

taken hourly, both day and night, for about one week, on the thermocouples in the interior of the bale, until they all reached a temperature somewhat in excess of 120° F., which was the temperature supposed to be necessary to destroy the boll weevil. A complete report

of the results of this test was submitted to the above-mentioned

bureau.

Tests of Household Refrigerators.

A comprehensive test of commercial refrigerators was carried out

for the War Department as a basis for the award of a contract.

These tests related to ice consumption, temperature distribution, and

air circulation within the refrigerators. As a result of the data obtained in these tests, the Bureau is endeavoring to cooperate with

manufacturers in the direction of improvement of this jiroduct.

Parts of this test of refrigerators are necessarily confidential, but

the parts that can be made public are summarized in a popular

manner in Circular No. 55, " Measurements of the Household."

It is hoped that an opportunity will be found to make more extensive tests along these lines, especially on the cheaper grades of

refrigerators in common use in the household. Deficient insulation

may result in unnecessary expenses and waste, and very often it would be possible for the manufacturer to very materially increase

the efficiency of his refrigerator without any very significant increase

in cost. Inefficiency is probably as often due to lack of knowledge

of the important features of the design, of physical properties of

mateiials used, etc., as it is to an attempt to cheapen manufacturing

costs.

Liquid-Air Plant.

The liquid-air plant has supplied liquid air to the several divisions of the Bureau as it has been required by the researches and

tests in progress. On several occasions liquid air has been furnished

for lectures before teachers' organizations. The carbon dioxide

compressor has been operated almost continuously throughout the

year to operate low-temperature baths required by the investigation

of refrigeration constants and by the thermometer laboratories.

Three new liquefiers have been constructed and tried out. One of

these has a capacity, when used with brine precooling, of about 6

liters of liquid air per hour.

A new electrolytic oxygen and hydrogen gas generator has been

installed for furnishing these gases to the chemical laboratories.
EEPORT OF DIEECTOR OF BUREAU OF STANDARDS. 37

Industrial Viscosimetry.

The most important laboratory test of the lubricating value of an

oil for the purpose in view is the viscosity test. The instruments

most widely used by the oil industries in the specifications of the

viscosities of lubricating oils, in domestic and foreign commerce, are the Saybolt-Universal, the Engier, and the Eedwood viscosimeters.

At the request of the American Society for Testing Materials and

of many industrial oil chemists, the Bureau undertook an intercomparison of these instruments and recently submitted a report of this

work to the above-mentioned society. This report contains suitable

conversion tables so that results found with any one type of these

instruments can at once be converted to the scale of either of the

other two types.

The Bureau is constantly receiving requests from technical men

for information on the measurement of the viscosity of lubricating

oils. Nearly fiftj'' long letters and reports were prepared during the

year in reply to such requests. More assistance is needed for this

work, which at present is carried as a side line by one whose time

is otherwise more than fully occupied. Important work that has been

deferred from year to year is the preparation of a circular on industrial viscosimetry which would serve to answer numerous inquiries

such as are referred to above. The Bureau is constantly in receipt of

requests for standard viscosity samples, which would enable oil chemists to standardize and check from time to time their viscosimeters,

in the same way that they now can check their heating value tests by

means of the standard heat samples furnished by the Bureau. This

work can be placed on a most satisfactory basis as soon as an assistant can be assigned to it.

Standardization of Flasb-Point Testers.

One of the important tests of an oil to determine its safety in use and its suitability for particular applications as well as for compli- ance with specifications is the determination of its flash point ; that

is, the temperature at which it gives off volatile vapors that will

ignite explosive!}^ if brought into contact with a flame or object at

high temperature. This flash point is dependent not alone upon the

chemical constitution of the oil, but is very materially influenced by

many other factors, such as whether the cup is open or closed, the

form and dimensions of the apparatus, the point of application of

the flame, the size of the latter and time of its application, the protection against air draughts, the height of the oil in the cup, the

degree of stirring of the oil, the method of taking the temperature of

the oil, the rate of heating the oil as the flash point is approached,

the barometric pressure, and many details of manipulation. Hence,

it is of importance to investigate the effect of these various factors

to enable the test to be standardized.

The Bureau has undertaken the standardization of the flash-point

testers of the Abel-Pensky and of the Pensky-Martens types as modified by the Bureau of Mines. Four of these instruments were

submitted for test in March, 1915, and a considerable amount of

experimental work was done with them. As a result of this work

certain modifications were proposed and are now under consideration

by the Bureau of Mines. Arrangements have also been made to
38 KEPOET OF DIEECTOB OF BUREAU OF STANDAEDS.

cooperate with that bureau on the preparation of the necessary

standardization specifications and of the operating directions.

Refrigeration Constants.

This very extensive investigation, undertaken at the request of

American refrigeration engineers expressed through their national

associations, includes the determination of the fundamental constants

of refrigeration engineering.

The VFork is being carried out with the cooperation of committees

of the American Association of Refrigeration and the American

Society of Refrigerating Engineers, the members of which visit the

Bureau annually, keep in close touch with the work, and have ren- dered valuable assistance by practical suggestions. The program is as follows

:

(a) The latent heat of fusion of ice.

(b) The specific heat of ice, —60° to the melting point.

(c) The specific and the latent heats of common refrigerants, such

as ammonia, aqueous ammonia solutions, carbon dioxide, and ethyl

chloride.

(d) The specific and the latent heats of the vapors of the common

refrigerants.

(e) The densities or specific volumes of the saturated vapors and

of the liquids commonly used as refrigerants.

(/) The vapor pressure-temperature relations of the substances

commonly used as refrigerants.

(g) The density-concentration relation for aqueous ammonia solutions.

(A) The vapor pressure-concentration relation for aqueous ammonia solutions.

(^) The specific heats of brines.

(j) The density-concentration-temperature relations of brines.

(k) The thermal conductivities of insulating materials used in

cold-storage construction.

(Z) Certain works problems, the solution of which seem to require

the facilities of this Bureau.

The investigation involved the original design and the construction in the instrument shops of the Bureau of a large number of

accurate and complicated pieces of apparatus. These have been re- modeled as the experience gained in their use dictated, and the actual

measurements made with them have progressed as follows

:

The measurements upon ice have been entirely completed and published (a) in Scientific Paper No. 209, reviewed in last year's annual

report, and (b) in Scientific Paper No. 248, reviewed in an earlier

paragraph of this report. The results of this latter were communicated to the American Society of Refrigerating Engineers at their

annual meeting in December, 1914, and are incorporated in the Transactions of that society.

The measurements upon ammonia received the principal attention

during the latter part of the year, and some of the results should be

ready for publication early in the coming year. In particular, the

measurements (c) of latent heat and specific heat of this substance

are well advanced.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 39

The thermal conductivities of insulating materials used in coldstorage construction are being determined in connection with similar

measurements upon materials used for insulation in other ways, an

investigation which is the subject of a special paragraph elsewhere in

this report.

Among the works problems which called for investigation by the

Bureau that of the presence of noncondensible gas in ammonia refrigeration systems received considerable attention. A preliminary re- port upon this subject was included in last year's annual report.

The Fire-Resisting Properties of Structural Materials.

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

structural materials is to furnish to architects, construction engineers,

builders, State and city building bureaus, insurance interests, and

others 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.

The wide scope of these investigations requires the close cooperation of many of the laboratories of the Bureau. Thus at present the

heat, weights and measures, electrical, concrete, ceramics, and structural materials laboratories are engaged on various phases of this

work, such as the measm-ement of high temperatures, the design and

construction of large furnaces for testing building panels and partitions, the fire tests of partitions built up of different structural materials, the determination of thermal conductivities and expansions of

various structural materials, safety rules for electric wiring and

problems appertaining to the national electrical code, etc., and the

load-carrying capacities of structural steel columns under exposure to

fire conditions when unprotected, partially protected, and fully protected by fireproofing coverings of different materials applied in

various thicknesses and in the various ways commonly used in building construction.

This work serves as an excellent illustration of the broad scope of

an engineering investigation that requires the cooperation of a number of the scientific and engineering laboratories of the Bureau.

Fire Tests of Building Columns.

Many millions of dollars are annually spent on the construction

of buildings, the integrity of which, in the event of fire, is dependent

on the behavior of the steel columns supporting the structures. Very

little engineering data are available which would permit of any cer- tain conclusions as to the thickness and kind of fireproof coveringrequired to render these columns safe imder various conditions of

fire hazard. The requirements of city building codes on these questions are so different that it is evident that some codes are either

requiring an unnecessarily thick fireproof covering, with undue in- crease 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 carried out jointly

with the Underwriters' Laboratories, of Chicago; the Mutual Laboratories, of Boston; and the Bureau of Standards. In the first

series of tests are included over 70 structural-steel, reinforced con-
40 EEPOET OF DIRECTOR OF BUREAU OF STANDARDS.

Crete, and cast-iron columns. The columns will be tested in a specially designed furnace now nearing completion in the Underwriters'

Laboratories in Chicago. The columns to be tested are designed for

a working load of 50 tons. Each column will be placed in the furnace, a constant follow-up load of 50 tons applied by a hydraulic

machine, and the column heated until it fails. The temperature in

the furnace and in various parts of the column will be measured by

suitable thermocouples; and the amount of deformation produced in

the column during the test will be measured by means of a suitable

apparatus which has been especially designed for this purpose.

The steel columns are of various types commonly used in building

construction, such as rolled H, plate and angle, plate and channel,

latticed channel, etc. Some of the columns will be tested unprotected,

some partially protected, and others full}'^ protected. The protective

coverings are concrete, plaster on metal lath, clay tile, and gypsum

tile. The protective coverings will be made from representative

materials obtained from different parts of the United States.

Much of the necessary preliminary work of this large program

of column tests has been done. It is expected that the protective coatings will be api^lied during the coming autumn and winter and that

the actual fire tests will begin in the spring of 1916.

Thermal Efficiencies of Column Coverings.

Tests are under way at the Pittsburgh laboratories of the Bureau

on the rate of temperature rise within cylindrical specimens of the

various materials used for fireproofing building columns, with a view

to supplementing and checking the results of the column tests. A

special gas-heating furnace has been built for this work and a large

number of cjdinders of different materials have been prepared with

suitable provision for inserting thermocouples axially, with their

junctions at different distances from the heated cylindrical surface.

Cylinders similar to the cylinder under test are placed at each end

of the latter, in contact with its end faces, to minimize the disturbing effects of heat losses from the ends.

Strength of Steel at High Temperatures.

As a preliminary to the tests of the building columns, some tests were made upon steel tubes to determine the relation between the

load they will support and the temperature to which they are heated.

The ultimate compressive strength was measured by mounting the

tubes in a testing machine, the tubes being heated quite uniformly

by a suitably spaced electric heating coil wound over the outside and

loss of heat from the ends being reduced to a minimum by asbestos

disks. The temperature was measured by a thermocouple within the

tube extending some distance beyond the center and then doubled

back on itself to minimize the effects of conduction to the cooler

ends. The behavior of such a tube may be expected to simulate

closely that of a steel column. The tests were made primarily to

obtain information as to what is to be expected in the much more

elaborate tests of actual columns, and to serve as a guide in the

design of the apparatus for those tests, especially the apparatus for

measuring the temperatures of the columns. The results of these

preliminary experiments seem to show that the protective covering on
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 41

a steel column, to be effective in a fire, must prevent the steel from

reaching a temperature in excess of about 625° C. (1,150° F.).

More elaborate tests on small building columns are to be made in a special furnace built for such tests at the Pittsburgh laboratories

of the Bureau.

Thermal Expansion of Structural Materials.

The weights and measures division has completed the designs for

an oil bath and for an electric furnace which provide facilities for

the determination of coefficients of expansion in the temperature

range from that of liquid air (about —190° C.) up to about 700° C.

The construction of these rather elaborate pieces of apparatus has

been completed in the instrument shops of the Bureau and will be

applied, as time permits, to the determination of the coefficients of

expansion of structural steels, the samj)les to be tested being taken

from different parts of the sections of large building columns and

girders of known composition and elastic properties.

Panel-Testing Furnace.

During the latter part of the fiscal year the erection of a penaltesting furnace was begun, which will afford the best modern facilities for testing the fire-resisting properties of building partitions, the test panel being 12 by 16 feet in area. The equipment

provided consists of an oil-burning furnace, with necessary boiler,

blower, oil tank, etc., 5 massive structural steel frames into which

the test panels are built, suitable trolleys, crane, structural steel

panel rack, etc., to enable the built-in panels to be moved into position

before the furnace, fire pump for applying the hose stream from a

l|-inch nozzle on the heated partition under test, to simulate fire

conditions, etc. This plant, when fully equipped with 7 additional

panel frames, will cost about $15,000 and will be the most complete

of its kind at present available. It is expected that fire tests can be

started early in the coming winter. Steps will be taken to formulate

a comprehensive program of fire tests of various building materials

after consultation with representatives of the various engineering

and technical societies and manufacturing associations interested in

the manufacture and use of these materials.

Building Codes.

The engineering data resulting from investigations such as those

above referred to must serve as the foundation upon which building codes must be constructed. Some progress has been made during

the year in compiling the municipal building codes, not alone with a view to furnishing information to State and city building bureaus

and to others interested along these lines, but with a view to a comparative study of existing codes to assist in planning a systematic

program of investigations to definitely answer the man_y important

questions about which there are still great differences of opinion.

Recommendations Concerning Fire-Resistance Investigations.

In the seA'eral preceding paragraphs there has been given a brief

summary of the work of the Bureau relating to the investigations of

the fire-resisting properties of structural materials. The data sup-
42 REPORT OF DIRECTOR OP BUREAU OF STANDARDS.

plied by such tests, however elaborate and comprehensive they may

be, will only be utilized to their fullest advantage after they have

been considered by all the numerous interests concerned and have

been finally incorporated into State and municipal building codes.

The goal toward which this work should tend, therefore, is to supply the necessary engineering data on which to base a much-needed

revision of our building codes. With the appropriations at present

available it is possible to undertake investigations on only a few of

the important features of building construction. Hence, as shown

by the foregoing summary, the present activities of the Bureau along

these lines are concentrated on the tests of building columns and of

building partitions. Many other important features of building con- struction should be made the subject of systematic investigations,

such as floors, roofing, fire doors and shutters, and wired glass. To

install a satisfactory equipment for testing floors under conditions

of load and fire will require about as much more. Upon the completion of the panel-testing furnace now being installed, the Bureau

will have a very complete plant that should be operated continuously

during the next few years in order to obtain the necessary data on

the many different materials entering into building construction.

This work is necessarily expensive, as it involves the testing to

destruction of full-sized specimens. With the present appropriation only occasional tests can be made and the present equipment,

therefore, only very inefficiently utilized.

Not all of the equipment referred to above should be immediately

provided. It is of great importance that one or more of the more

important items be provided each year in order that the several

lines of investigation can be carried along together, thus rendering

possible the accumulation of the necessary engineering data to warrant a revision of our building codes within a reasonable time, say

the next five or six years.

Along with the investigations referred to, a number of subsidiary

investigations having an important bearing on building construction

should be carried out, such as sprinkler systems, storage of inflammables, and temperature actually attained in various types of fires

from field inspections and special laboratory tests. In the last few years many public organizations have become

active in a nation-wide campaign to reduce the present annual fire

losses of a quarter of a billion dolla-rs. The Bureau should do its

part to assist in this great movement for National conservation.

To provide for the immediate requirements of this work, namely,

the installation of the necessary facilities for beginning the fire tests on floors, fire doors, roofs, etc., and for the continuous and efficient

operation of the large panel-testing furnace now nearing completion,

it is recommended that the appropriation for this work be increased

to $50,000 a year.

Fire Tests of Insulated Sheet-Metal Cabinets.

At the request of the General Supply Committee, the Bureau made

a number of fire tests on insulated sheet-metal cabinets of the type

that had been submitted to that committee for the award of contract

for the ensuing year. The cabinets tested were 7 in number, the product of six different manufacturers, and were purchased on the open
REPOET OF DIEECTOB OF BUREAU OP STANDARDS. 43

market. The dimensions of the cabinets varied somewhat, but were

about 6 feet by 3 feet by 2 feet.

The test was made by mounting the cabinet within a large gas

furnace in such a way that the cabinet was exposed to the flames on

all sides. Thermocuples mounted on the outside of the cabinet, but

near its outer walls, and in the interior space of the cabinet, served to

measure the temperatures. Paper and small pieces of wood were

also placed on the shelves within the cabinet. The temperature, as recorded by the thermocuples in the furnace, was raised quite rapidly

to 1,500° to 1,700° F. A temperature of 400° F., which is sufficient

to seriously damage contained documents, was reached in the various

cabinets in from 6 to 23 minutes after starting the fire in the furnace.

After the tests the cabinets were taken apart and examined for details

of construction, insulation, damage to contents, operation of doors,

etc. A detailed report of the tests was sent to the General Supply

Committee.

While one of the conditions of these tests, namely, exposure to fire

on all six sides, was more severe than would be likely to prevail in

an actual fire, this fact would not materially influence the relative

rating of the several cabinets and it would not affect the conclusion

that these cabinets do not alford sufficient protection to contained

documents when they are used where the fire hazards are even moderately severe. In fireproof buildings, with steel furniture, and little

combustible matter to support a fii'e, their use would he perfectly

safe, but in buildings having wooden floors, furniture, etc., and

sufficient combustible matter to support even a moderate fire for half

an hour or so, most of these cabinets would not afford sufficient protection to contained documents.

In view of the fact that some of the cabinets included in these tests are extensively advertised by the makers as safe under the most severe

fire conditions, and even as being approved by the Government, it seems probable that at least a part of the public may be misled into a false sense of security in using some makes of cabinets for the storage of valuable documents.

An examination of the cabinets after they were taken apart showed

that in most cases there was only a thin layer of insulating material

between the inner and outer sheet-metal walls, a thick layer of air

being depended upon for thermal insulation. The construction of

these cabinets seems to indicate that there is a very general misunderstanding as to the insulating properties of an air space. While it is

true that the thermal conductivity of quiescent air is very low, yet

under the conditions prevailing in these cabinets when exposed to

high temperatures there is a very large amount of heat transmitted

through an unobstructed layer of air by convective circulation of the

air and by radiation through the air. The amount of heat thus transmitted can be very much reduced by a suitable insulating material.

In vieAV of the very unsatisfactory conditions found as a result of

these tests, a report was sent to each manufacturer whose product

Avas included in these tests, giving in detail the results of the tests of his product and containing suggestions for improvement. The

Bureau has since received communications from a number of manufacturers stating that a much-improved product had been developed

and requesting that the Bureau make further tests along the same
44 EEPOET OF DIEECTOR OF BTJEEAU OF STANDAEDS.

lines, a request which it is hoped can be met if the present crowded

schedule of work will permit.

Melting Point of Concrete.

The melting point of 11 samples of concrete that had been through

the Edison fire was determined with a view to ascertaining the temperatures that had been attained in this fire, some of the concrete in

this fire being in a condition which showed evidence of softening

and flow.

Observations in Connection with the International Ice Patrol of

1915-

In connection with the International Ice Patrol of the U. S. Coast

Guard cutter Seneca^ the Bureau was represented on all the cruises

of that vessel by one obserA^er and on one of the cruises by two

observers. Practically continuous records were obtained of the temperatures of the sea water, including a rather detailed study of

the temperatures of the currents off the Banks of NeAvfoundland and

vicinity, with frequent determinations of the densities of the sea water, current measurements on the tail of the Great Bank, and

some further observations on the temperature variations of sea water in the immediate vicinity of icebergs. Work done on atmospheric nucleation with respect to the formation of fog, including

measurements of corona and of total liquid contents of fogs, is

described in another section of this report.

Testing of Heat and Thermometric Apparatus.

During the year 1,300 mercurial thermometers of various kinds

were submitted for test, of which 1,190 were certified. Among those

submitted, there were 278 ordinary calorimetric thermometers, 78

precision calorimetric thermometers, 17 clinical standards, and the

remainder laboratory and special thermometers of various types and

ranges from below 0° to 500° C, including 5 recording thermometers.

About 1.8 per cent were received broken and about 2.7 per cent were

broken in the course of testing.

Sixteen thousand five hundred and twenty-four clinical thermometers were submitted for test ; of this niimber 14,929, or 90.4 per cent,

were certified. The j^ercentage of those rejected amounted to 9.6

per cent of the total number submitted; 0.8 per cent were rejected

on account of defects in construction, 1.1 per cent because of too

great difficulty in throwing back index, 0.4 per cent on account of

retreating of index, 0.4 per cent were received broken, 0.5 per cent

were broken in testing, and 6.4 per cent exceeded the limits of allowable errors. In addition to the above, there were tested a total of 7 platinum

resistance thermometers and 1 indicator for a platinum resistance

thermometer.

Among the calorimetric tests made by the Bureau, 11 were for the

heating value of fuel oils and bituminous materials, 2 of calorifiers

(instruments for transferring a known amount of heat), 4 of gas

calorimeters, 253 standard heat samples, 1 for the specific heat of

linseed oil, and 1 for the determination of the water equivalent of

a bomb calorimeter.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 45

In the high-temperature laboratories there were tested 3 radiation

pyrometers, 11 optical pyrometers, 1 absorption glass for optical

pyrometers, 35 rare-metal thei-mocouples, 8 base-metal thermocouples,

6 thermocouples with pyrometer galvanometers, 3 pyrometer galvanometers, and 1-1 homogeneity tests of thermocouples.

Among tests involving the melting points of various materials, 9

Avere for fire brick, 11 for concrete material, 3 for high-temperature

cements, and 3 for metals.

Besides the above testing, a number of special tests were made involving 3 fire tests of building stones, 6 determinations of the melting

points of samples of ceresene, 1 determination of the melting points

of samples of paraffin, 6 cold tests of rubber samples, several determinations of the freezing points of samples of fire-extinguisher fluids,

9 efficiency tests of refrigerators, and 30 determinations of thermal

conductivities. Other special work carried on was the preparation

of a special steel ingot, soft outside and hard inside; a study of the

behavior of silicon carbide ware in air at 1,800° C. ; the preparation

of carbides in an electric furnace; a study of the temperature con- ductivity of bales of cotton ; and the standardization of a pyroheliometer.

Almost every variety of industry and manufacturing interests is represented in the above summary of tests, as well as Government,

State, and municipal bureaus and commissions, technical schools,

universities, etc. Among the thermometers tested were included a number of working standards used by manufacturers to control the

accuracy of thousands of thermometers put on the market; the

clinical thermometers were tested for the several medical bureaus of

the Government, State medical institutions, manufacturers, hospitals,

dealers, physicians, and individuals ; calorimeters were tested for the

gas industries and State commissions; and standard heat samples

were furnished to numerous industrial jjlants using large supplies of

fuel. In the high-temperature tests of pyrometers, melting points,

etc., are represented every variety of industry in which the control

and measurement of high temperatures is an important factor in the

product of the plant, such as iron and steel plants and allied industries, cement, gas, and ceramic plants; electric manufacturing

companies; manufacturers of high-temperature measuring apparatus,

tools, springs, axles, automobiles, etc. ; as well as technical and university laboratories, etc. Of the total work of testing done by the division of heat and

thermometry, somewhat less than half is done for the various

bureaus of the Government, the remainder for the general public.

Information Furnished, Reports, Etc.

An important feature of the work of this division has been the

information that has been furnished by means of letters, and often

quite complete reports, on subjects related to its lines of work. Several hundred sucla communications were prepared during the year.

The requests for information came from nearly every type of industry; from manufacturers; National, State, and municipal laborartories and bureaus; from scientific investigators; from committees

of engineering and technical societies; and from many others. The

subjects treated were of every variety; for example, thermometry;
46 EEPORT OF DIKECTOB OF BTJEEAU OF STANDARDS.

thermometer specifications; comparators for testing thermometers;

thermoelectric pyrometers; cold junction corrections; optical pyrometers; radiation pyrometers; installations suited to particular

requirements; calorimetry; heating value tests of gases; specific

heats of liquids and gases: heats of combustion of gases; definition

of the British thermal unit ; melting points of oxides, fire bricks, ash,

cements, etc. ; refractory glazes ; decomposition temperature of calcium carbonate; thermal concluctivities of insulating materials,

bricks, etc. ; apparatus for testing thermal conductivities ; testing of

steel car sections; containers for molten oxides; tests of refrigerators; fire tests of insulated steel cabinets; baffle plates and burners;

viscosity measurements; conversion tables; flash-point testers; re- sistance of pipes to the flow of liquids and gases; design of gasburner nozzle; design of aeroplanes and windmills; windage of flywheels and steam turbines; ventilation; commercial separation of

oxygen and nitrogen by air liquefaction ; uses of liquid air ; heat of

sublimation of ice below 0° C. ; rules for the computation of horsepower of hydraulic and steam turbines; and condensation of moisture on iron car roofs.

New Work and Equipment for Heat and Thermometry.

A number of metals and salts, of accurately determined melting

points, should be certified by the Bureau and supplied to technical

men to enable them to quickly and conveniently check the accuracy

of their pyrometers, just as standard combu.stion samples now furnished by the Bureau serve to check heating value tests. Numerous

requests have been received by the Bureau to furnish such standard

melting-point samples. The necessary preliminary work to issuing

such samples can be started as soon as frmds are available for purchasing a sufficient supply of materials. The fees received for the

standard samples would nearly, if not quite, pay for the work and

materials.

A number of important items of equipment, which have been

deferred from year to year, are urgently needed and should be provided for, such as electric furnaces, heavy current transformers and

rheostats with the necessary special wiring, thermocouples, refractory porcelain for high-temperature work, bomb calorimeters, gas

tanks, standard thermometers, and a new resistance bridge.

3. ELECTRICITY.

Weston Standard Cell.

Studies continue in progress on the Weston normal cell, the primary standard of electromotive force. The aim of this work, which

has extended over a niunber of years, is to secure control OA^er all the

factors afl'ecting this fundamental standard. Cells may then be

constructed according to a definite procedure, such as to have a predetermined electromotive force accurate to a few parts in a million, and such as to continue unchanged indefinitely. The chief source of variation in the cell is the mercurous sulphate. It has

been ascertained that this substance, when prepared by alternatingcurrent electrolysis, gives very constant electromotive force, but different samples do not quite agTee. The study of these differences is
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 47

actively in progress. It has been found that the preliminary washing produces negligible elfect, while acid strength and temperature

are important causes of variation. The effects of the rate of stirring

and size of grain are imder investigation, indications being that

fine-grained samples give higher electromotive forces than the

coarser-grained samples.

The type of standard cell used in ordinary electrical measurements, the unsaturated Weston cell, is under investigation as to its

reproducibility and constancy. Such cells when set up with alternating-current mercurous sulphate were found to be very constant.

Mercury Standard Ohm.

The unit of electric resistance is defined by international agreement in terms of a specified column of mercur}^ in a glass tube at

the temperature of melting ice. Such standards have been set up at • the Bureau, and the paper describing the work is in press. (See

Scientific Paper No. 256.)

Silver Voltameter.

The international ampere adopted by the International Electrical

Congress (London, 1908) as one of the two primary electrical standards is defined as the continuous current which deposits silver from

an aqueous solution of silver nitrate at the rate of 0.00111800 gram

per second, under certain conditions. The instrument used in making such deposits of silver is the silver voltameter. Many investigators have published the results of their experiments with this

instrument, but at the time of the electrical congress much remained

to be learned about it. The Bureau has actively prosecuted its re- searches in this subject for several years past and has published six

papers on the subject. During the last year the Bureau has cooperated with Prof. Hulett, of Princeton University, who had previously

made an extended study of various voltameter problems. The re- sults of this work include the discovery of a hitherto unsuspected

source of error in washing the deposits of silver. The Bureau's

'

work and Prof. Hulett's work have now been brought into excellent

agreement. (See Scientific Paper No. 240.) The last few months

have been spent in an effort to determine the amounts of foreign substances deposited with the silver. These are commonly called " inclusions." A considerable number of deposits have been heated to over 600° C. both with a flame and in a furnace to expel these inclusions. The very concordant results which have been obtained indicate the inclusions to be about 0.004 per cent on the average when

the electrolyte is pure. This Bureau- has previously published

0.00111804 as the value it has determined for the electrochemical

equivalent of silver by means of its voltameters and absolute current

balance. The latest work on inclusions, mentioned above, now makes

it appear that the value 0.00111800, the figure adopted by the London

Electrical Congress, is the best assignable value for the electrochemical equivalent. On the above basis we are now able to compute

anew the value for the faraday, which is an important constant in

the science of physical chemistry. It is equal to 107.88 (the atomic

weight of silver) divided by 0.00111800, which is 96,494 coulombs.
48 KEPOKT OF DrKECTOB OF BUREAU OF STANDARDS.

This value can not be accepted as settled, however, inasmuch as

official specifications for the silver voltameter have not yet been

agreed to internationally. It is probable, however, that the value

96,500 for the faraday is within a hundredth of 1 per cent of the

true value expressed either in absolute or international coulombs;

that is, coulombs defined in terms of the absolute or international

ampere, which are numerically in extremely close agreement.

Inductance of Electrical Shunts.

A study has been made of the inductance of resistance standards

such as are used in the measurement of large currents. (See Scientific Paper No. 246. ) The ordinary methods can not be used for the

measurement of such inductances, because these standards are fourterminal conductors of a special form. Two methods were devised

for the purpose and were found to work well in the laboratory.

Simple Method for Testing Electrical Instrument Transformers.

A method was developed for testing instrument transformers by

the aid of ordinary watthour meters, such as are used in buildings

to measure the consumption of electrical energy. (See Scientific

Paper No. 233.) Attempts to determine the ratio and phase angle

of these transformers by using watthour meters in both primary and

secondary circuits have not met with much success. The method

here developed is to determine simply the difference between two

transformers, one of them being a standard. It was discovered in

connection with this work that commercial watthour meters are constant enough in their performance to serve as test instruments in

this comparison, their variation in successive tests being surprisingly

small.

Measurement of Earth Resistivity.

A knowledge of the electrical resistivity of earth is often neces- sary in connection with grounding electrical systems and in the study

of the effect of stray currents in the earth. An improvement in the

methods of measuring earth resistivity has been made by using four

electrodes and considering the measurement to be that of a fourterminal conductor. The troublesome large resistances at the electrodes are thereby eliminated. A paper describing the method has

been prepared.

Standard Air Electrical Condensers.

For some time there has been a need for better standard air con- densers for use in the alternating current measurements at the

Bureau. Such condensers consist of two sets of metal plates interleaved with one another, the two sets being electrically insulated

from each other. It is very difficult to make them mechanically rigid.

Great improvements have been made in this respect by a new design

using quartz insulators. A number of the new condensers have been

constructed, and are found to have a very constant electrical capacity.

The capacity does not change with frequency of charge and discharge.

New air condensers have also been designed and constructed for use in radiotelegraphy. The plates have a spiral shape, such as to

facilitate many of the high-frequency measurements.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 49

Galvanometers.

One of the investigations in progress relates to the sensitiveness

of galvanometers. These are used in various kinds of electrical

measurements in which the accuracy or precision must be high;

such, for example, as the comparison of resistance standards (on the

values of which measurements of electrical power depend) and the

measurement of temperature to 0.001° C. hj means of resistance

thermometers.

A paper on the general design of sensitive galvanometers has been

prepared. The paper gives and discusses the mathematical relation

between the operating constants of a galvanometer and the factors

entering into its construction, such as the magnetic field and the

shape, size, and kind of material of its parts. Procedures are outlined for the construction of galvanometers for various particular

purposes.

For industrial purposes alternating current is largely used. This

has necessitated the development of methods for testing alternatingcurrent apparatus and as progress is made there is a demand

for higher accuracy in the measurements. Where a high accuracy

is required null or balance methods are usually employed and these

require some kind of detector which will give a definite indication

when an alternating current is passed through it. For certain classes

of work a telephone receiver answers the purpose very well, but for

alternating currents of low frequencies it is very insensitive. In

such cases the vibration galvanometer is much more sensitive and is

used to a considerable extent. In some classes of work, however,

there is a need for a still mere sensitive detector. By a careful study

of the problem, making use of the experience gained in the construction and use of sensitive galvanometers for direct current, alternating-current galvanometers of high sensibility are being developed.

The theory of the separately excited galvanometer has been studied and such instruments have been constructed and used. The

performance of these galvanometers can be varied by changing the

constants of the circuits to which they are connected. They can be

made as sensitive as the best direct-current galvanometers, and are

particularly useful in alternating-current bridge measurements. A

scientific paper on these instruments has been prepared for publication.

Parallel-Decade Potentiometer.

An improvement in the accurate measurement of temperature has

been made possible by a new potentiometer designed here and constructed during the spring. The small electromotive forces used in

the thermoelectric method of temperature measurement can be measured with increased accuracy by means of this instrument. The set- tings of the potentiometer are varied by moving a high-resistance

shunt from one set of coils to another. Thermal electromotive forces

generated at the sliding switches do not materially affect the measuring circuit.

Circular on Electric Measuring Instruments.

Bureau Circular No. 20 has been thoroughly revised and brought

up to date. This new edition was prepared with the cooperation of

10739°—15 i
50 KEPOET or DIRECTOR OF BUREAU OF STANDARDS.

a number of engineers and instrument makers and the meter committee of the National Electric Light Association. This necessitated

a number of conferences and considerable correspondence. The circular presents the principles underlying the construction and operation of commercial electrical instruments, together with information

concerning the advantages and limitations of the various types such

as will assist the user to determine which general type is best suited

to a given purpose. The design, sources of error, and the testing of

electric instruments are treated.

Measurement of Conductivity of Electrolytes.

The electrical division cooperated with an investigator working

under the Carnegie Institution of Washington in this research, the

work being done at the Bureau. Most liquid conductors of electricity are electrolytes, and no satisfactory methods of measuring

their conductivity have hitherto been perfected. To eliminate disturbing factors, one of the first requirements is a source of alternating current free from harmonics. Several types of generators were

investigated, and one was found suitable. A satisfactory measuring

bridge was developed. The conditions were found for eliminating

the effect of change in voltage upon the measured conductivity. The

effect of frequency of the measuring current and the effect of the

type of electrodes were studied. Very high accuracy was attained

in the final measurements.

Resistance and Inductance of Bimetallic Wires.

Wires made up of a steel core with an outer copper sheath are used in electric power transmission and in telephone work; having

greater strength than copper wires, they can be used in longer spsns.

Accurate data on the electrical properties of these wires has been

lacking. The resistance and inductance vary with the frequency of

alternation of the current. Measurements of these quantities were

made, and formulas and tables prepared, for the commercial sizes

and grades of copper clad steel wire and iron telegraph wires. (See

Scientific Paper No. 252.) In connection Avith the work, a study

was made of the magnetization of an iron wire by a current flowing

through it. Magnetic Method of Determining Flaws in Steel Rails.

An examination of the possibility of detecting flaws in steel rails

by a magnetic method has been in progress for some time. Two

15-foot sections of an 80-pound rail were used. Artificial flaws introduced into these specimens can be located by magnetic measure- ments made with large coils which are arranged to slide along the

rails. This investigation is carried on in cooperation with the engineering division of the Bureau, the mechanical tests and magnetic

tests being complementary. The results so far obtained indicate

that the magnetic method of finding flaws in rails may possibly become commercially feasible, although much remains to be done in

that direction.

Correlation of Magnetic and Mechanical Properties.

The investigation seeking to correlate the magnetic and mechanical

properties of steel continues in progress. Data have been collected
REPORT OF DIRECTOR OE BUREAU OF STANDARDS. 51

on the magnetic and mechanical properties of several series of carbon

and alloy steels after different heat treatments.

Magnetic Permeameters.

A thorough investigation of an important type of permeameter

was completed during the year. (See Scientific Paper No. 228.)

This is an instrument for measuring magnetic permeability, and has

been extensively used in the past for commercial testing. This permeameter consists essentially of a magnetic circuit in which there is

interposed a suspended coil carrying a constant current. A deflection of the coil is a measure of the induction through the specimen

of iron under test. It was found that the indications of the instrument require corrections in some cases as large as 100 per cent. The

correction is different for different grades of test specimens. It was

concluded that with great care in its use, such a permeameter is capable of yielding results sufficiently accurate for commercial requirements.

A new permeameter has been developed at the Bureau. It is capable of measuring permeability with speed and accuracy. By its use

it was found that some of the standard magnetic bars prepared by

the laboratory five years ago were not sufficiently homogeneous. A

new set of standard bars has been prepared, examined for homogeneity, and carefully measured for their magnetic constants.

Temperature Coefficient of Magnetic Permeability.

Magnetic tests of iron are ordinarily made without regard to the

temperature of the sj^ecimen. When an accuracy of 1 per cent in the

permeability is required, the temperature has to be considered. An

investigation just completed has shown that temperature coefficients

may be as great as one-third of 1 per cent per degree. A knowledge of

this is important not only because room temperatures vary, but also

because the bar of iron may be 10° to 20° C. higher in temperature

than the room, owing to the heat developed in the magnetizing coils.

The results of test on a given material can not be corrected to standard temperature by means of data obtained from other materials,

because the temperature coefficient is different for different materials

and even for the same material with different heat treatments. The

only generally reliable way to avoid errors arising from the effect of

temperature upon permeability is to regulate the temperature of the

specimen under test. (See Scientific Paper No. 245.)

Core Losses in Iron at High Inductions.

One of the chief considerations in the design of dynamos and other

electric power apparatus is the limitation of power loss due to heating in the iron. It is, therefore, of great importance to have an

accurate Imowledge of the behavior of iron when subject to magnetizations such as cause large losses of power. This has been the subject

of special study for some time past. It has thus far been possible to

extend the measurements from the former limit of 10,000 to 15,000

units of induction.
52 KEPOET OF DIRECTOR OF BUREAU OF STANDARDS.

Magnetic Circular.

Bureau Circular No. 17 on magnetic testing has been revised and

extended and will shortly be issued. The methods used at the Bureau

are explained in detail. This information has frequently been sought

in inquiries addressed to the Bureau. Information is given upon empirical formulas for approximate calculations of induction and core

loss. Typical characteristics of ordinary commercial magnetic materials such as are used in electromagnets and permanent magnets are

given. The circular is a valuable compendium of information on

magnetism.

Radium Testing.

There has been a great increase in the volume of testing which the

radium laboratory has been called on to do for the public. The

apparatus for the testing of radium salts is being improved. The

Bureau has been called upon to measure single specimens that contain nearly 16 times as much radium as the largest standard. To

facilitate such work a set of lead filters has been carefully standardized. By sci-eening the electroscope with lead plates, it has been

found possible to measure satisfactorily a specimen containing 16

times as much radium as the standard. Further studies in connection with such measurements are being made. The method is not,

however, so satisfactory as it would be if the laboratory possessed a supply of radium more nearly comparable with the large specimens

sometimes submitted for test.

Increase in the Bureau's Stock of Radium.

An increase in the Bureau's stock of radium is needed. The Bureau

should have a much larger standard of radium than at present. Large

test specimens could then be standardized by a more direct comparison, and the present 15 milligram standard could be placed in the

vault and retained with greater safety as a primary standard.

Alpha Ray Activity of Uranium Oxide Powder.

A study of the alpha ray activity of uranium oxide powder has

thrown doubt upon the validity of such activity as a guide to the

amount of radioactive material contained.

Radium Emanation.

Second only in importance to the study of radium salts is the investigation of radium emanation. Such work has been carried on

throughout the past year. The equipment is being continually improved. An interesting auxiliary is a 1,500-volt battery made up of

dry cells such as are used in flash lights.

Circular on Radium.

Part of the work of the radium laboratory is to act as a clearing

house of information. Attention is being given to the indexing and

abstracting of the literature on radium. A circular is in preparation, setting forth in a popular manner those facts concerning

radium and radioactivity and their technical measurement which

are of general interest or which should be clearly understood by all

who desire to employ radium or the allied substances in any way.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 53

Radio Communication.

The radio laboratory has assisted the Bureau of Navigation of the

Department of Commerce with technical information from time to

time, and has designed, tested, and adjusted instruments used in

examining the radio equipment of ships by the inspectors of that

Bureau.

Radio Sets for Lighthouse Tenders.

Five complete radio equipments for the Bureau of Lighthouses

were designed and their construction supervised by this laboratory.

They are installed on lighthouse tenders and are provided with a number of special features adapted to the needs of the lighthouse

service. As a result of the attention given to the design of these sets,

they were purchased at a smaller price than the usual commercial

sets of the same range, and are much more efficient in the service for

which they are intended. In the development of this equipment,

valuable experience and information were gained which could hardly

have been obtained in any other way. The tenders equipped with

radio apparatus will be of greater service in promoting safety at sea than ever before. Being at no time cut olf from communication

with the lighthouse or with ships, they will be a much greater aid to

navigation.

Radio Interference.

An investigation was made of a case of alleged interference caused

by a large power arc operated by a commercial company, at the re- quest of the Bureau of Navigation. Other companies and the Navy

Department complained that this company was sending out wave

lengths not allowed to it by law, such as to cause troublesome interference with radio messages from other sources. The company

claimed that it was sending only wave lengths within the legally prescribed limits. A study of the waves actually used by the company

showed that while the main sending wave length was as the company

claimed, the apparatus gave rise to subsidiary and shorter waves

which caused the trouble. It has not heretofore been recognized

that arc generators may send out reinforced harmonics of the fundamental wave in such volume as to cause interference.

Promotion of Safety at Sea.

Some improvements in radio apparatus are being developed which

will be of assistance particularly to those branches of the Government having to do with the protection of life and property at sea. One of these is a fog-signaling device. With such a device automatically sending out radio waves, either on a ship or at a lighthouse,

other ships could navigate in a fog with greater safety. Another

device which if successful would be of great assistance in navigation is a direction finder. This relatively simple apparatus permits

the operator of a radio set to determine from what direction a message is being sent. This should be of great advantage, especially

in emergencies. The device is under study.

Design of Inductance Coils for Radio Work.

A study has been made of the practical design of inductance coils

for use in high-frequency circuits, such as wave meters, receiving
54 REPOET OF DIRECTOR OE BUREAU OF STANDARDS.

tuners, and transmitters. The inductance coil is one of the two most

important elements of a radio circuit, and information as to the

proper design of such coils is being continually sought by the manufacturer and user of radio apparatus. A number of coiis have been

received from manufacturers, colleges, and Government departments,

and tested at frequencies ranging from 50,000 to 1,000,000 cycles

per second.

Proposed Work in Radiotelegraphy.

A number of additional lines of work in radiotelegraphy have

been either begun or planned for the coming year. The design of

radio apparatus is at present limited by lack of precise data on the

high-frequency resistance of conductors of various forms. Investigation will, therefore, be made of the resistance of straight wires and

strips and coils of various shapes, wound with various kinds of wires,

and mounted in various ways. Of like importance is new data on

the dielectric losses in various types of radio condensers. The

methods of measuring resistance, current, and wave length at high

frequencies are being studied.

Information as to the behavior of different types of antennas is

urgently needed. At present the ground resistance, radiation resistance, and other characteristics of various types of antennas can not be

determined with great accuracy. The methods of measuring resist- ance and capacity of antennas should be studied, together with the

question of the dielectric and hysteretic properties of the soil. Permanent towers are needed, upon which experimental antennas can be

mounted, so that the problems now in hand and others which will

arise may be adequately treated.

The use of radiotelegraphy by this Government to promote safety

and as an aid to navigation has been by no means as thoroughly developed as it might well be. This Bureau hopes to be of greater

assistance to other civil branches of the Government in the future

than it has been able to be heretofore, particularly to such as are engaged in the protection of life and property at sea. Such assistance

may take the form of information upon the technical possibilities

of radio instruments and equipment, the standardization of apparatus, and the adaptation of radio equipment to the particular needs

of a given service.

Additional Facilities Needed in Radiotelegraph Work.

The increasing requirements of the radiotelegraphic work, as to

space and experimental facilities, necessitate a separate building.

Auxiliary to the building there should be two towers about 150 feet

in height for the support of experimental antennas. The building

would house not only the radio laboratory of the Bureau but also

those of the Army and Navy, now located in a few of the rooms of

the Bureau laboratories. Considerable work has been done in the

Bureau laboratory, as has already been outlined on preceding pages,

but the rapidly increasing importance and range of radiotelegraphy

demands a considerable extension of the work, for which the present

space and facilities are quite inadequate. Not alone the design of

radio apparatus and the assistance of other bureaus in securing suitable equipment, but a thorough study of the scientific principles

underlying the art, are urgently needed. An appropriation of $50,000
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 65

for a building for this work has been requested. This request is

renewed. An increase from $10,000 to $20,000 of the appropriation

for apparatus and for assistance in connection with tlie radio work

is also desired. The Bureau of _ Standards is an ideal place for the

location of a well-equipped radio laboratory. The close proximity

of the radio laboratory to the other scientific and instrumental re- sources of the Bureau would be a distinct advantage. The building

would be two stories in height, would be located south of the electrical laboratory, and would be connected by means of a tunnel with

the other buildings, so that all the generators and other facilities of

the Bureau would be directly available.

Effect of Atmospheric Conditions on Flame Standards of Candlepower.

In the pursuit of its plans for putting tests of gas on a more exact

basis, the Bureau found it necessary some years ago to make a special

study of the flame standards of candlepower which are used for such

tests. In order to be able to calibrate such lamps accurately at all seasons of the year a precise knowledge of the effect of atmospheric

conditions was necessary, for variations due to these conditions may

be as great as 20 per cent. Thorough determinations of the effect

of humidity were made, the results of which have been confirmed

by all the more recent tests. In order to certify the candlepowers which the standards would

have in cities at different altitudes, however, it is necessary also to

know the effect of changes in barometric pressure, and the natural

variations in pressure in Washington were not sufficient to determine this effect over the required range. A set of tanks was therefore constructed in which the lamps could be supplied with the

proper flow of air at a high or at low pressure, while the corresponding candlepowers were measured by a suitable photometer.

Such measurements have been made on the best types of standard

lamps and also on the types of gas burners most commonly used in

tests. The same apparatus has been used for exact determinations

of the effect of humidity on the gas flame, which has never before

been made. This work is now ready for pviblicaticn, and will show - more fully than has heretofore been done the real significance of the

results of tests of gas under various conditions.

Photometry of Lights of Slight Color Difference.

The tendency in recent developments of lamps has been continually

toward the production of whiter light, so that exact comparison with

the older standard lamps to which all our measurements must be re- ferred becomes increasingly difficult. The work done last year in determining the equations of curves showing the changes in candlepower and efficiency of tungsten lamps when the voltage is changed

has been published in Scientific Paper No. 238, and the results have

been widely used in lamp factories. Another paper, dealing particularly with certain peculiar difficulties which arise in the measure- ment of the new gas-filled incandescent lamps, has been prepared

for publication.

All measurements of lights differing in color from the fundamental

carbon standards have hitherto been essentially unsatisfactory, for
56 KEPOKT OF DIRECTOR OF BUREAU OF STANDARDS.

two reasons—in the first place it is very difficult for any one to judge

when equality has been obtained in the photometer, and hence the

results vary erratically; in the second place, when enough measure- ments have been made to average out these erratic variations there

still remain differences between individuals. In other words, the

candlepower really is different for different observers, and the proper

value to assign is that which the average person would get.

It is hardly justifiable to assume that the few men in a laboratory

fairly represent the average of people in general imless some test has been made to show their relation to that average. Such tests have recently been devised, but have not been sufficiently well tried

out to be generally adopted.

The Bureau (in cooperation with the research committee of the

Ilhiminating Engineering Society) has planned an extensive investigation to consist of (1) the establishment of average values by

having 100 or more observers make measurements on certain colored

lights; (2) a test of the proposed method of choosing observers who

properly represent the average thus established; and (3), if the

method proves to be practical, the calibration of colored glasses, solutions, multivoltage standard lamps, and other devices which are used

to obviate the difficulty due to color. This work is just being started

and is to be prosecuted as actively as possible during the summer,

while the amount of routine testing is small.

Illuminating Engineering.

Provision is needed to enable the Bureau to take up in an adequate

manner some of the most urgent problems in illuminating engineering

that concern municipalities. The lighting of streets and public

spaces, public buildings and auditoriums, stores, factories, and private

homes is a matter that is receiving a great deal of attention in recent

years, and a great many new and improved methods, as well as fixtures and appliances for the purpose, have been developed; but re- liable information as to the value of much of this material is hard

to obtain.

The claims made by manufacturers are often conflicting, and there

is a great need for an unbiased agency, such as the Bureau of Standards, to make photometric and other tests and to determine the performance of the appliances that are on the market. For the use of

the Government, States, and cities alone such information would be

of great value, but it would also be of immense value to the general

public, and particularly to architects and contractors who are specifying and purchasing such appliances. We know also from tests which

we have made that improvements at practically no cost could often

be made if the necessary information were available. The subject

is a highly technical one and directly in line with the Bureau's work,

and a moderate appropriation would yield valuable results.

During the past year information has been collected regarding

street lighting from a large number of cities, and it is expected that a careful study of this data will furnish results of interest to many

cities. Some of the experimental work done is mentioned under the

heading " Photometry."
REPOET OF DIRECTOR OF BUREAU OF STANDARDS. 57

Electrical Testing.

Standards, instruments, and materials are tested by seven sections

of the electrical division. In the following enumeration, the more

important tests for the Government are so indicated.

Standard cells arid resistance apparatus.—Tests were made during

the year on 74 Weston portable cells, 6 Weston normal cells, 1 Carhart-Clark cell, 11 precision rheostats, 6 potentiometers, 8 volt boxes,

9 wheatstone bridges, 12 resistance standards for current measurement, 83 precision resistance standards, and 99 wires and cables for

conductivity measurement. Of the last item, 95 were for the Panama

Canal.

Capacity and inductance.—The tests for capacity and inductance

included 17 electric condensers, 6 inductance coils, 2 measurements of

inductance of resistance coils, and 7 insulation resistance tests. A

test was made of the dielectric constant of some varnished cambrics

for use in a high-voltage transformer. It was found that the apparent dielectric constant varies with the air space in the condenser in

which the material is used. The effect increases with the heterogeneity of the dielectric.

Radium.—There were tested by the electric division during the

past year 82 specimens of radium and mesothorium. These specimens, 14 of which were for the Government, aggregated 2.127 grams

of radium, valued at $254,000. One large test was of 250 miligrams

for Italy, for use in hospitals and laboratories there. Some of the

specimens in this lot were found to be mounted in a slightly defective

manner; this case is an example of the service which the Bureau

frequently renders by pointing out defects in standards as well as testing them. There were also 3 tests of emanation of radioactive

water, 11 standard sohitions and emanation standards, and 2 samples

of radioactive material. The last was a special test for the Department of Agriculture.

Electric measuring instruments, etc.—The following tests were

made for the public: 14 voltmeters, 22 ammeters, 13 wattmeters, 30

watthour meters, 18 voltage transformers, 32 current transformers,

2 special transformers, 12 samples of wire, 5 samples of tape, 6 pairs

of rubber gloves, 2 recording potentiometers, and 8 dielite cylinders.

The following articles were tested for the Government: 7 voltmeters, 4 ammeters, 2 wattmeters, 3 watthour meters, 1 current transformer, 15 motors, 35 dry cells, 16 samples of wire and cable, 38

samples of tape, 1 sample of varnish, 2 samples of sheet insulation,

34 transformer coils, 150 pairs of rubber gloves, 15 porcelain insulators, 1 glass insulator, 4 electric " healing " devices, and 37 electric

fans. The electric fans were tested for the General Supply Committee. Measurements of air delivery and relative efficiency are used

by the General Supply Committee in awarding the annual contracts

for electric fans.

Magnetism.—^Magnetic materials tested during the past year included 69 samples of iron for measurements of normal induction,

21 determinations of hysteresis, 51 core loss measurements, and 3

miscellaneous magnetic tests. Photometry.—1,253,604 electric lamps were inspected and 3,141

lamps life tested for the various Government departments; of the
58 EEPOET OF DIEECTOE OF BUEEAU OF STANDAEDS.

former 692,745 lamps were tungsten and the rest carbon, and

of the latter 2,400 were tungsten and the rest carbon. Other tests

for the Government were 86 reflectors and globes, 4 spherical reduction factors of electric lamps, 30 samples of kerosene and signal oils,

2 portable photometers, 1 illnminometer, 1 comparison of illumination from motion-picture machines, 1 test of acetylene signal lamps,

and 21 gun-sight lamps. The following tests were made for the

public: 140 incandescent lamps tested for candlepower, 2 color

screens, 11 pentane lamps, 1 hefner lamiD, 1 sample of pentane, 1

retinal sensivity tester, 2 luminous arc lamps, 1 kerosene mantle

lamp, and 4 luminous-flame oil lamps.

Besides routine tests of lamps, reflectors, photometers, etc., the

following tests of special interest have been made. Samples of the

two most wideh!- used types of " luminous arc " lamps for street

lighting were' tested to determine their efficiency, the distribution of

the light, and the life of the electrodes. Comparative measurements

of the illumination furnished by several kinds of motion-picture

machines were made as a basis for the choice of a type of which a large number were to be purchased by various Government departments. An acetylene signal lamp used by the Coast and Geodetic

Survey for long-range triangulation was tested and experiments

were made to show the great increase in intensity which could be

gained by using a concentrated filament electric lamp instead of

the acetylene flame. A kerosene mantle lamp was measured in comparison with luminous flame lamps and found to give about four

times as much light for a given consumption of oil. Photometric

tests of kerosene oils have only recently been begun by the Bureau

;

this year 30 samples were tested for the Government following the

procedure outlined in the specifications. The specifications are not

sufficiently definite in many respects, and when possible the tests have been made under different conditions to determine the effect

of various factors not sufficiently well defined. Although kerosene

is the illuminant used by more people than any other, its effective use has received comparatively little study, and considerable effort

might profitably be expended in determining the properties of the

oil which affect its illuminating value.

Among the photometers calibrated was one to be used by the

Public Health Service in studying illumination in factories and in

some of the Government offices. Another photometer, which was

tested for the Weather Bureau, was fitted with reducing screens and

color screens to extend the range of the instrument so as to make

possible measurements of intensities up to that of direct sunlight,

while a third, intended for the Bureau's street-lighting investigations, was fitted with absorbing screens to make possible the measure- ment of illumination in poorly lighted streets; the extreme range

covered by these instruments was such that the highest illumination

measured was about 1,000,000 times the lowest.

The life tests made on incandescent lamps supplied under Government contracts showed that the quality of these lamps is being steadily improved, so that although the requirements of the specifications

have been materially raised in the last year nearly all the lamps

supplied to the Government passed the life requirements by a con- siderable margin. The advantage gained by conducting these tests
EEPORT OF DIEECTOE OF BUEEAU OF STANDAEDS. 59

is well illustrated by the results of a test made by the Bureau on

lamps supplied by coiitractors to the State Hospital of New York,

where tests are not regularly made. It developed that the lamps

which were being supplied were decidedly inferior to those which

the Federal Government obtains. A few tests of the life of lamps

were also made for private parties in cases where circumstances made

the tests of sufficient importance to justify the work being done here.

Considerable time was spent on a test of gun-sight lamps for use

in the Navy. This included a determination of the best intensity

for such use and a test of several types of lamps made up for trial.

A satisfactory form was finally obtained, and specifications for it

formulated.

Radio instruments.—Tests of radio instruments included 5 wave

meters, 5 inductance coils, 1 variable condenser, and 10 decremeters,

5 of which were made for the Government.

The above list of tests does not include a considerable number of

magnetic tests, tests of Weston cells, etc., made for various laboratories of the Bureau.

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 in replying to particular requests. Some instances from the correspondence of the electrical division during the

past year may be given.

A great many inquiries regarding radium and radioactive preparations were received and answered. The subjects included the

testing of therapeutic preparations, water activators, etc. The cor- respondence shows the need of a circular of information on radioactivity. This has been in preparation and will shortly be issued.

The Bureau is a repository, not only of scientific, technical, and

commercial standards, but also of exact information in regard to

units and standards. Compilers of physical tables seek such information from the Bureau. Material on units and electrical data

were furnished for new editions of two books of tables during the

year.

A variety of information has been furnished on the subject of radiotelegraphy. Suggestions for research, bibliographies, data on design and performance of coils, and particulars regarding the practical details of radio stations were among the information supplied.

Valuable service has been rendered by preparing opinions as to the

technical worth of certain fraudulent devices. One of these was a primary battery alleged by the inventor to have extraordinary

efficiency. It was supposed to be such an economical source of energy

as to be superior to dynamos for the supply of electric heat, and

could be used for the heating of houses. These claims have been used

to extract large sums of money from the public. An inspection of

the battery and a few simple tests showed that the claims amounted

to a contradiction of well-lcnown laws of nature, and that the battery is in the ordinary class of batteries such as are used for door

bells and signal systems. In such cases, the Bureau cooperates with

other branches of the Government concerned. Sometimes the case
60 EEPOET OF DIEECTOE OF BUEEAU OF STANDAEDS,

leads to court processes, and sometimes to postal fraud orders.

Another class of electric fraud embraces a number of devices supposed to cure diseases or otherwise benefit the human body. Several

of these were submitted and examined during the year. " Electric " and " magnetic " rings and other appliances for the cure of all bodily

ills have had a vogue for many years, and it is extremely difficult to

eradicate them. Possibly a public statement as to their utter absence

of electric or magnetic action will be of some assistance in discrediting them.

Public-Utility Investigations.

The electrical work so far mentioned has to do with the determination and maintenance of electrical standards, the investigation of

methods of measurement, study of the electrical properties of materials, the design and improvement of instruments, and the testing of

instruments and materials, all of this being done in the fields of

electricity, magnetism, and photometry.

Another large and important field of work, some of which has

more of an engineering character than most of the 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 scientific and engineering research, the

study of public relations questions, the preparation of specifications

regarding the quality of service, methods of testing and inspection

employed by municipalities and commissions, safety rules for use by the utility companies to safeguard their employees and the public,

and the collection and distribution of information by published

papers and through correspondence.

Service Standards for Illuminating Gas.

This work has been carried on for several years under the direction

of the electrical division, with the cooperation of the other divisions

of the Bureau, especially the chemical and heat divisions. Regulations for gas service, as made by cities or State commissions, include

among other things the requirements as to meter accuracy and the

testing of meters, the specifications of the heating value or candlepower of the gas (or both), the degree of chemical purity as ex- pressed by the limits set to the amounts of sulphur and ammonia

that are permitted, the variations in pressure that may be allowed,

and the manner and frequency of tests to determine whether the

operating companies conform to the requirements.

In addition to investigations carried on by the Bureau for the past

five years on this subject, which have resulted in a considerable number of papers published in the Bureau's scientific and technological

series, a careful study was made of the rules and regulations of cities

and States, and a thorough discussion made of the subject in Bureau

Circular No. 32, first published fou^r years ago. This was revised

and republished two years ago and a third edition has been prepared

and published during the past year. This publication has had a wide circulation and serves a most useful purpose in setting forth

the proper basis for regulations; it also discusses the relation between

the quality of gas and the efficiency of manufacturing processes, and

the most satisfactory terms in which to specify gas quality and

methods of testing.
REPORT OF DIRECTOR OP BUREAU OF STANDARDS. 61

This circular also contains model ordinances for the use of cities

which control their own utilities, and state rules suitable for the

adoption of State commissions which fix the standards of service for

all the companies of a State.

In the original preparation of this circular as well as in its subsequent revisions the Bureau has had the cooperation of the gas industry, a special committee of the American Gas Institute having

read the manuscript and offered suggestions. Many engineers of

cities and commissions also gave similar assistance.

The advantage of having such cooperation between representatives

of the industry, of the public, and of a disinterested national institution that is possessed of ample experimental facilities is obvious. It

results in rules and requirements that are more nearly just and adequate, gives to the public greater confidence in the service of the

utilities, and makes recourse to the courts much less frequent.

Another publication issued during the year is Circular No. 48,

which gives a detailed technical discussion of methods of gas testing.

This was the joint work of several divisions of the Bureau.

The Bureau has given assistance to a considerable number of State

commissions and cities in connection with the adoption of ordinances

or orders regarding gas service, and has sent a representative to a number of public hearings conducted by State commissions during

the year. It is of much importance that the regulations and requirements of the several States and cities shall be as uniform as consistent with progress and justice to the companies and the public.

The Bureau aims to serve in some measui'e as a clearing house of information on many of the scientific and public relations questions

arising in connection with the regulation of gas companies, and to be

perfectly impartial as between the companies and the public.

Electric Light and Power Service.

During the past two years the Bureau has been studying the question of the specifications for electric light and power service, and the

requirements that should be made by cities or State commissions of

public-utility companies furnishing such service. This study is similar to the studies described above concerning gas service and the

conclusions and recommendations resulting from the study will be

shortly published as Bureau Circular No. 56. The principal factors

of such service are its quality and reliability, and the accuracy of

the meters that measure it. Steadiness of voltage and continuity of

service, without which electric lighting is not satisfactory, are phases

of quality and reliability that have sometimes been included in regiilatory ordinances, while the permissible errors of meters and frequency of testing of the same are almost always included. As the

requirements that can fairly be made differ under different circumstances, it has been necessary to prepare more than one set of specifications for cities. Hence, three model ordinances have been prepared, one for large cities, one for medium-sized cities, and one for small

cities and towns. In the first the requirements are more detailed

and the quality of service required is higher than for smaller places.

In the third, requirements are fewer and inspections by the city or town are not contemplated; but the character of service to be ex- pected is specified and there is a basis for further requirements when

practicable.
62 KEPOKT OF DIRECTOR OF BUREAU OF STANDARDS.

A set of rules suitable for adoption by State commissions has also

been prepared, and a digest given of the requirements of all the rules

now in force by commissions.

In this work also we have had the cooperation of the electric companies and State commissions, many valuable criticisms and suggestions having been received after reading the manuscript. The Bureau has cooperated for years with the meter committee of the National Electric Light Association, and one of the important subjects

of the new circular is meter testing and meter accuracy.

At the invitation of public-service commissions, representatives of

the Bureau have attended a number of hearings in various States

where proposed rules for the regulation of electric service were under,

discussion, and have given commissions assistance in formulating

such rules. In every case the Bureau seeks, while representing the

public interest, to get the utility's point of view also, and has always

consulted the utilities concerned before publishing any proposals or suggestions as to rules or regulations.

Cooperation with the Underwriters' Laboratories.

Another question now being studied came to the Bureau because

of its relations with the Underwriters' Laboratories. The Bureau co- operates with the Underwriters' Laboratories in some of its work,

and had an agreement whereby appeals may be made to the Bureau

in certain cases where the rulings of the laboratories are protested.

The Underwriters' Laboratories is a private institiation, but is performing a public function, and it is thought desirable that an appeal

to a public body should be possible without resort to courts of law,

especially since the questions at issue are usually of a scientific or engineering nature.

The first case under this arrangement to come to the Bureau was

a joint appeal by the Underwriters' Laboratories and a manufacturer of renewable cartridge fuses, a device for protecting electric

circuits. The Bureau is making a thorough investigation of various

types of approA^ed nonrenewable fuses as well as the renewable fuse

under discussion, and is examining fuses as they are used. It is also

conferring with insurance and municipal inspectors and engineers

who have had experience with various types of inclosed fuses. Some

of the experiments are being made in the Bureau's laboratories, and

others in power stations where a large amount of power is available

for the larger sizes of fuses. Some of these tests are to be made in

conjunction with certain of the fuse manufacturers. Wlien the

question is decided and a report rendered, a full digest of the experiments and all the evidence gathered will be published, so that the

public will be able to judge as to the merits of the question at issue.

The case is of great importance to manufacturers and to the public.

Electrolysis Mitigation.

The majority portion 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 cui-rent 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
EEPOKT OF DIEECTOE OF BUEEAU OF STANDAEDS. 63

the lead sheaths of underground telephone and electric light cables,

and sometimes through reinforced concrete structures. The earth

conducts electricity by virtue of its moisture and the salts dissolved

in it, which renders it an electrolyte. Hence, when the electric cur- rent 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 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 caused the trouble. But although the courts have considered the question of legal responsibility,

these cases did very little to prevent the trouble in an effective and

economical manner.

The Bureau has been studying the question for the past five years

and has done a large amount of work in connection with it. This has

included laboratory investigations concerning the effects of electric

current on concrete and metal pipes, tests of pipe coverings, the cor- rosion of metals in the soil, methods of measuring soil resistance, and

various other experimental phases of the work; methods of electrolysis mitigation that have been used or proposed and the results

obtained; field studies in actual practice with the application of

remedies and a determination of the cost and results obtained.

During the past year some additional work was done in St. Louis

and Springfield (Ohio) and a very complete report prepared on the

survey made at Springfield, Mass.

This survey was made at the invitation of the city of Springfield,

and most of the public-utility companies of the city, including the

gas, electric-light, telephone, and telegraph companies. The railway

company did not unite in the invitation, but gave the engineers of

the Bureau free access to its property and full information regarding

its current, cables, and station operation. The cost of the survey and

the report is borne in part by the Bureau and in part by the utilities.

The object of the work is not merely to benefit Springfield, but to

demonstrate the method of procedure in making electrolysis surveys,

and in securing relief from electrolytic corrosion in an efficient and

economical manner. A complete electrolysis survey was also made in

Altoona, Pa., and a full report thereon submitted to the city and

utility companies.

Another phase of the electrolysis work is the studying of the various methods of bonding rails at joints so as to provide good con- ductance for the electric current flowing through the rails. The three

aspects of these joints which are most important are their permanence, their conductance, and their cost. A very thorough study of
64 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

the subject has been made and a full report is being prepared for

publication. In this work the Bureau has had the full cooperation

of many of the electric railway companies and the manufacturers of

rail bonds.

Still another phase of the subject is the question of roadbed resistance, since the amount of electric current flowing away from the

tracks is reduced when the electric resistance from rails to earth is

increased. In order to get definite information to aid the Bureau in

making recommendations to railway companies, a number of sec- tions of roadbed have been constructed on the Bureau grounds, and

their resistance measured from time to time.

The work of the Bureau on electrolysis has been received most

favorably by many railway officials and engineers, but very many

still feel that it is a hardship to provide adequate conductors for the

return current, having for so long been accustomed to turning it loose

in the earth to return as best it could.

Lightning Protection.

A study of the protection of buildings against lightning has been

in progress for several years, and a publication on the subject has

been prepared, to be issued as Technologic Paper No. 56. This includes a full discussion of the methods of lightning protection, the

results of experience as shown by vital statistics and the records of

fire-insurance companies, and other interesting information. The

work Avill be contimied and specifications prepared for protecting

different kinds of buildings so as to make it easier for architects and

owners who wish to place lightning protectors on various types of

structures to do so as efficiently and economically as possible. The

Bureau has conferred Avith the manufacturers of lightning protection material and hopes to have their further cooperation in preparing specifications for protection systems. Additional papers prepared for publication during the year included Electrolysis and its

Mitigations (Technologic Paper No. 52), Report on Electrolysis Conditions in Elyria, Ohio (Technologic Paper No. 54) , and Report on

Electrolysis Conditions in Springfield, Ohio (Technologic Paper

No. 65).

National Electrical Safety Code.

The Bureau has been engaged for two years in the study of the

life hazard in electrical practice and in the preparation of a national

electrical safety code. In this work it has had the cordial cooperation and assistance of a large number of the ablest and most experienced engineers of the country, many of whom are connected with

the electrical operating and manufacturing companies, and others

are engineers and inspectors of State commissions and municipalities.

The importance of having a national code, uniform in all the States,

is quite as important for safety rules as for rules for reducing the

fire hazard; and the advantage of having such a code prepared by

an unbiased national agency that can study the subject thoroughly

and consult all the interests affected is obvious. One of the four

parts of the code, namely, the part containing the rules to be observed

in the operation of electrical equipment and lines, was published as Bureau Circular No. 49 nearly a year ago and republished last May
REPORT OF DIRECTOR OF BUREAU OP STANDARDS. 65

after revision with the cooperation of the National Electric Light

Association and many electrical companies and engineers of commissions. The other three parts of the code, in preliminary form, were

published as Bureau Circular No. 54 last April after several manuscript editions had been successively revised and rewritten. Eepresentatives of the Bureau have held conferences in many cities on the

subject, extending from Boston to San Francisco, and have collected

an immense amount of information and criticism which is now being

used in the revision of the code, preparatory to a second preliminary

publication. In the near future there will be held in Washington

a national conference on this code; delegates will attend from the

various engineering societies, several of the State commissions, a number of the larger cities, insurance interests, the National Council

of SafetjT^, and a delegate from each of the groups of engineers with

whom we have held conferences in the various cities. This will be

a very representatiA^e gathering, and it will be asked to discuss,

amend, and approve the national electrical safety code, which by the

time it is presented for discussion will probably have imdergone more

thorough study and discussion than has any similar set of rules

before being adopted by an administrative body.

National Gas Safety Code.

The Bureau is also engaged in the preparation of a national gas

safety code, along the same general lines as the electrical code, and

is receiving the cordial support of the gas industry. This work has

been taken up more recently and has not progTessed far enough to

publish more than an outline. The safety code will consist of five

parts, as follows

:

1. The manufacture of gas.

2. The distribution of gas.

3. The design, construction and testing of gas appliances.

4. The piping of buildings and the installation of fixtures and

appliances.

6. The use of gas and the care of appliances.

The first two parts of the rules will apply to the gas companies

and their employees; the third to the manufacturers of gas appliances; the fourth to plumbers and gas fitters and the inspection

department of cities; the fifth to the users of gas, domestic and

industrial.

There can be no question as to the great need of such a safety code,

and we have every reason to expect the fullest cooperation of all

the interests alfected in its preparation.

Telephony.

The Bureau has done comparatively little in the testing of telephone transmitting and receiving apparatus and switchboard equipment, but is now taking i;p this important work and hopes to develop it in an adequate manner. Telephone standards need to be

fixed and facilities provided for making tests whenever required

by cities or public service commissions, as well as when requested by

telephone companies or by manufacturers of telephone apparatus

and equipment.

On the plea of public convenience and necessity for interchange

of service, petitions for physical connection between telephone sys10739°—15 5
66 EEPOET OF DIRECTOR OP BUREAU OF STANDARDS.

terns under different ownership, whether operated in different localities or in the same locality, and even cases involving the connection

between intercommunicating systems in hotels, business establishments, etc., with one or both local operating companies, are being

brought before public service commissions with increasing frequency.

One of the questions involved is whether, if such physical connections were granted, the transmission of speech between telephones of

the two systems would or would not be impaired by such connections in comparison Avith the transmission between two telephones of

the same system. This question, as well as the more general question

of what is proper and adequate service under given conditions, and

many others, are susceptible of experimental study, and the representatives of the public should have facilities for such tests available, and competent and experienced persons to make the tests. The Bureau will cooperate with manufacturing and operating

telephone companies and telephone associations, as well as with State

commissions and city officials, in this as in other public-utility work.

Relation of the Bureau to Municipalities and Public-Service Commissions.

In some States there are no public-service commissions to issue

regulations or inspect the quality and safety of the service rendered

by the various utilities. In some other States the railroad or publicservice commissions have taken no action in the matter, although

having authority to do so. In either case the cities and towns must

look after their own interests, and frequently have taken up the

matter with enterprise and undei'standing. Where there are wellequipped and active State commissions, which have adopted rules

and are ready to hear complaints regarding rates or service, still a veiy 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 each case, and relieve the municipalities of all responsibility. On the contrary, if the municipalities are active and enterprising in their own behalf, and the larger ones have well-equipped

]3ublic-utility departments, which can prepare the city's complaints

or requests and take them up to the State commission for hearing

and adjudication, the State commission 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 it is a difficult matter to judge as to the quality

of service rendered by its utilities. The studies made by the Bureau

of Standards have been directed toward simplifying this problem

by providing well-defined specifications of what constitutes good

service, and the Bureau has a considerable correspondence with commissions and cities on this subject. The resources of the Bureau,

however, are not sufficient to enable it to do as much as ought to

be done, and some of the most important subjects in this connection

have not been taken up at all. It will obviously never be practicable for any State commission or

city to handle these questions alone. Though they possess large and

able engineering staffs or emplqy specialists for each separate problem, the question of what is good service or whether the service in
BEPOET OF DIKECTOR OF BUREAU OF STANDARDS. 67

any given case is adequate, safe, and satisfactory can only be settled

by refei'ence 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 in a large way. One method of doing it is

for the States and cities to get together and establish a special

bureau or institution for the purpose, the several States and cities

paying for any service derived therefrom. The new Utilities Bureau

of Philadelphia is such an institution, and there is ample field for

its activities. But it has appeared very desirable for a bureau of

the Federal Government to do a certain portion of the work ; hence,

the Bureau of Standards has been doing this in a somewhat experimental waj'' to test the desirability and acceptability of the method.

The success and approval which the work has met so far seem to

justify its expansion.

Necessity for Increasing the Public-Utility Work of the Bureau.

The sum available for the public-utility work of the Bureau,

including a special appropriation for the safety work, is $40,000 per

year, and allowing for the supervision and assistance rendered from

ithe general funds it may be considered as $50,000 per year. Many

of the States spend more than this, and some States five or ten times

as much. The people of the United States spend about two billion

dollars 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 four million dollars a year regulating the utilities and railroads, and the cities a large

amount in addition. A considerable sum could profitably be spent

annually in an efficiently conducted cooperative study of the con- duct 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 pviblic-utility and associated engineering questions, helping to secure uniform methods of accounting 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 requires a great many conferences and discussions, and the harmonizing of

differences of opinion. Many such differences of opinion are due to

lack of precise information. Often experimental or other studies

clear up sTich differences and bring about uniformity of practice.

A Federal bureau well equipped with men and apparatus, and permitted to work in the A'ery wide field of public utilities (outside of

railroad transportation and such subjects as the Interstate Commerce Commission is concerned with), would 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
68 REPORT OF DIRECTOR OE BUREAU OF STANDARDS.

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 is a reasonable estimate of the possible value of the service

we are considering, assuming such service to be efficient and ample.

One cent a year per capita does not seem too much for the people to

spend through the Federal Government to accomplish this result.

At present the Bureau of Standards is s]3ending one-twentieth of

this, and has accomplished enough to show how valuable such work

is. If the funds available for this woi'k could be gi-adually increased

as the work develops until each person in the country was contributing, say, only one-fourth of a cent per year, and the total was

one-fourth of a million dollars, the sum would still be less than several of the larger States are spending alone, and yet the results of

the work being made available for every St'ate would yield in the

aggregate a large return to the people. Considering the enormous

cost of i:)ublic-utility service, it does not appear to be desirable to

continue spending so much withoiit a greater effort to derive the

benefits possible from a just and adequate system of public-utility

regulation.

But the money value of proper regulation of the utilities is not

the only benefit to be derived therefrom. The increase of safety and

reduction of accidents 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 uitilities are sometimes

forced to resort to questionable methods in self-defense. Public offi- cials charged with the du:ty of regulating public utilities, but not

proT'ided with means of doing it equitably and effectively, are almost

helpless.

4. OPTICS.

Determination of Standard Light Wave Lengths.

The determination of standard wave lengths has been continued

throughout the year. The growing importance of spectroscopic

analysis adds importance to this work and the need of standard wave

lengths will be illustrated in the following paragi-aphs. During the

year 131 standard wave lengths in the iron spectrum were published

in Scientific Paper No. 251. The region covered in this publication

extends from wave length 2,850 A to 3,700 A, all in the ultraviolet

(1 A=0.0000001 mm.). The work on the visible portion of the iron

spectrum is well imder way and will soon be ready for publication.

OAving to their extreme sensitiveness to red and infrared, photographic plates which ai-e prepared at the Bureau will enable us to

carry these investigations far into the infrared.

The prosecution of this piece of research necessitated the installation of a concave grating, apparatus for sensitizing photographic

plates, apparatus for depositing. metallic films cathodically, and the

addition of considerable other laboratory equipment. Aside from

sixpphdng half-silvered mirrors for interference work, the cathodic

apparatus has been useful in coating galvanometer mirrors with
REPOBT OF DIRECTOR OF BUREAU OP STANDARDS. 69

platinum, and in plating mica with platinum for constructing a special condenser. Another by-product of this research wa3 the determination of certain wave lengths in the neon spectrum. (See

Scientific Paper No. 251.)

Information Furnished on Spectroscopic Subjects.

The spectroscopic information furnished to Government bureaus

and to firms and individuals has been of quite a varied nature. In

most instances this information could be given at once, but in the

following cases some investigation was necessary. A suitable source for violet and ultraviolet light was found for the Bureau of Chemistry. The detection of minute quantities of impurities in ammonia

by spectroscopic means was investigated at the request of the division

of chemistry. The purity of electrolytic iron was investigated for the

metallurgical division. This investigation led to the correct indentification of certain lines in the iron spectrum which are due to impurities. It also showed the extreme difficulty of obtaining iron

entirely free from manganese, copper, and silicon.

Investigation of Vacuum Tubes of the Rare Gases.

For this investigation quartz vacuum tubes with sealed-in electrodes were furnished by the Cooper-Hewitt Electric Co., and filled

either at this Bureau or by Sir W. Ramsey. The' investigation

showed that the spectra of these gases have not been determined with

sufficient care, and a more extensive study of these spectra will be

necessary before the purity of the gases can be proven. It is certain

that Xenon is seldom, if ever, free from Krypton, and, conversely,

Krypton probably contains Xenon.

Quantitative Spectroscopic Analysis of Steel.

This subject was investigated at the request of various manufacturers of steel. At present, in the judgment of the majority of eminent spectroscopists, the quantitative spectroscopic analysis of steel can be made only by an experienced observer at the expense of great

labor and the exercise of much patience. An attempt has been made

to bring the subject within the scope of the average analytical chemist and to increase the accuracy of the results. The results to date are

quite encouraging. The preliminary work is rather large, but once it has been done the labor of analysis is not great. Consider a single

simple example, the estimation of the chromium content of a lowcarbon steel. Leaving the other constituents of the steel essentially in

the same proportions, samples are made up, or selected from stock,

having a chromium content of 0.02 to 4.00 per cent, each sample having about 25 per cent more chromium than the one before. The

spectrum of each of these samples is photographed, and the comparison of a photograph of the spectrum of the unlmown with this series

pei'mits an estimation of the chromium content to be made with some

accuracy. In the case of the elements niobium and molybdenum, the

estimation of small quantities by spectroscopic means is more reliable

than the chemical analysis. In general, the spectroscopic rivals the

chemical analysis wherever the element in question is present in quantities less than 5 parts in 10,000.
70 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Spectroscopic Analysis of an Alloy which is Liquid at Room Temperatures.

This unique alloy was sent to the Bureau for analysis. The chemical analysis proved to be very difficult and a spectroscopic examination was made at the request of the chemical division. The sample

was found to consist of gallium, indium, and zinc. It contained no

mercury nor cadmium. In the course of the investigation, the spectra

of the rare elements gallium and indium were found to be incorrectly

determined and a redetermination, using purer material than has

been hitherto employed, is greatly to be desired.

Spectroscopic Tests.

The ultra-violet transmission of two absorption cells was determined for the Weather Bureau. The performance of a spectroscope

was investigated for the Bureau of Chemistry. Tests of the ultraA'iolet transmission of samples of glass have been made for various

manufacturing firms.

Standardization of Industrial Sugar Testing.

The absence of standardized methods of testing sugars and sugar

products has long been a handicap to the industry. The values of the

materials tested make it necessary to secure the most accurate tests possible. Owing to the lack of a central standardizing bureau in the

Western Hemisphere, the industrial concerns were for many years

thrown entirely upon their own resources to obtain methods of test- ing. Hence, a diversity of methods of testing existed, not only among

the companies doing business in the United States, but also between

this and other countries with which the United States does a large

import business. The Bureau has, therefoi"e, increased its efforts

toward securing the adoption of standardized methods where experts

are in disagreement as to the best methods, and then to make these

standardized methods available to Central and South American countries. Circular No. M, on Polai'imetry, has been issued. The interest aroused is shown by the demand for this publication, not only

from this coyntry, but also from all parts of the woiid. The first

edition was soon exhausted and the work of revising for a new and

more complete edition is now in progress

Conference of Polarimetric Experts.

The work of obtaining standardized methods of sugar testing

would be greatly facilitated by calling a conference of the scientists

interested. It lias been suggested that if such a conference could be

brought about it would be possible to secure an agreement on important methods which have long been in dispute. The Bureau hopes

to take the initiative in this matter during the coming year.

Constants of the Saccharimeter.

Several years ago an investigation of the reading of chemically

pure sugar on the scale of the saccharimeter (a polariscope for testing

sugars) was undertaken. This is of fundamental importance, since

this reading fixes the 100-degree point of the sugar scale in terms of

which the purities of other sugars are determined. The 100-degree
REPOBT OF DIEECTOR OF BUREAU OF STANDARDS. Tl

point now used by the Bureau for standardization purposes and by

the greater portion of the sugar world was determined by Euro^oean

Governments. The Bureau's investigation shows that this constant

is too high by over one-tenth of a per cent, a relatively large error. The loss to our Government in duties that should have been collected on imported sugars amounts to over $50,000 a year and the producers of raw sugars have received less compensation than they

should have received. - The importance of the issue as brought forward by the Bureau's

investigation was recognized by the International Sugar Commission by appointing an international commission with one member

from each of three countries—the United States, Germany, and

Austria. A member of the Bureau was appointed chairman. Owing

to the present conditions abroad, no cooperative work has so far been

attempted. The Bureau's investigation has, however, been extended

and new values have been obtained for a number of other constants

which are dependent on the 100-degree point of the saccharimeter

and which are of great importance to the sugar industry, and for

scientific purposes. Out of this new work has come additional evidence which strengthens the Bureau's position on the question of the

error in the 100-degree point. The necessity for a common basis of

testing to be agreed upon by the leading nations is of such importance

that the Bureau is still testing all apparatus and the Treasury Department is still collecting the revenue on sugar, on the basis given

by the old value of the 100-degree point. It is hoped that a change

to the new and correct value can soon be made.

The Specific Rotation of Pure Sugar.

Perhaps the most important of the physical constants of pure sugar

(sucrose) is its specific rotation; that is, the rotation of the plane

of polarized light by a solution containing unit weight in unit volume.

This constant expressed in circular degrees has been studied for

many years by the various countries interested. Because of the high

purity of the sugar and the precision of measurement required in the

research on the constants of the saccharimeter already referred to, advantage was taken of the opportunity to obtain a very accurate determination of the specific rotation. The value secured for sodium

light was 66? 529 at 20° C.

The Rotation Dispersion of Sucrose (Cane Sugar),

The amount of the rotation of the plane of polarized light by pure

sugar is different for different colors. This variation has not been

studied for many_ years. A more accurate knowledge of these

phenomena is required by manufacturers if further advancement in

saccharimeter design is to be made. Preliminary measurements have

been made and they show a disagreement with the results obtained

by previous investigators.

Pure and Intense Light Sources for Polarization Work.

The attempt to measure accurately the rotations of sugar for different wave lengths (colors) of light has necessitated further study of

the problem of obtaining pure and intense sources of light. This is

perhaps the most troublesome problem in polarimetric work. Never-
Y2 REPOET or DIRECTOK OF BUREAU OP STANDARDS.

tlieless, considerable progress was made during the year. A burner

for either sodium or lithium has been perfected, and improvements

made in the rotating cadmium-silver arc. These, together with the

quartz mercury vapor lamp, are capable of giving intense light of

various wave lengths fairly uniformly distributed throughout the

visible spectrum.

In addition some time has been spent on the study of dispersive

systems for producing pure light of high intensity with a view to

finding more suitable dispersive materials, but this work has suffered

on account of the scarcity of optical glasses due to conditions abroad.

Referee Work upon Molasses Testing.

The use of the exhausted molasses from the manufacture of cane sugar for road making, cattle feeding, and distilliftg purposes is

steadily increasing. Only a few years ago this by-product was in

many instances thrown into the sea in order to get it out of the way.

It is now being shipped to this country in large quantities. The distillers especially are dependent upon it for the preparation of alcohol

and alcoholic products by the fermentation of the sugar contained.

The molasses is sold on the basis of its total sugar content and to

determine this has never ceased being a problem to both buyer and

seller. In order to obtain the total sugar, it is necessary to determine

not only the sucrose, but also the invert sugar or " glucose " and any

other varieties of sugar which may be present. The appraisal of the

molasses is based upon the analyses of buyer and seller and a third

analyst who acts as a i"eferee. The continued disagi'eement between

the results of the different analysts finally resulted in the Bureau

being requested to act in the capacity of referee, and, furthermore,

to advise in the selection of suitable analytical methods. It was

found that among the methods in vogue are some which although

recommended by apparently reliable authorities are seriously at fault.

The inherent difficulty of the test as well as the need of selecting the

proper methods of procedure will require considerable investigation.

This work has progressed satisfactorily and in the meantime the

Bureau has made the referee tests on the samples from a number of

importations.

The Optical Rotation of Dextrose (Grape Sugar or Glucose).

Dextrose or glucose, sugars of which grape sugar is an example, is a substance widely distributed in nature but is nowhere to be obtained in a pure state. Inasmuch as 'the analysis of materials con- taining it depends upon a knowledge of the properties of the pure

dextrose, much effort has been spent in purifying the substance and

investigating its properties. The investigation of its optical rotation

upon the saccharimeter which permits the use of white light sources,

and upon the polarimeter, which requires monochromatic sources,

has been continued and will be available for publication during the

current year. One manufacturing firm has written to the Bureau

for information upon this problem. The substance is also available

as a standard for controlling the analysis of reducing sugars, a

large class of sugars not including sucrose, which are analyzed by

their chemical effect upon copper in alkaline solution.
KEPOET OF DIBECTOE OF BUEEAU OF STANDAEDS. 73

The Optical Rotation of Levulose (Fruit Sugar).

Levulose or " fruit sugar " is of wide occurrence, but, like dextrose, is never found in a pure state. The work of preparation and

purification has been continued and a few preliminary measurements

made. Inasmuch as the rotation of this substance is particularly

susceptible to changes of temperature, apparatus has been constructed

to control the latter very precisely during the polarization. This

apparatus has also been of use in the work upon molasses, which also

demands precise temperature control.

Samples of Standard Sugars.

The work of preparing and issuing standard samples of sucrose and dextrose to be used in the standardization of saccharimeters and

for standards of combustion has been continued, owing to the constantly increasing demand by manufacturers and scientists for these

materials. A total of 91 standard samples of the sucrose and dextrose were issued during the year. This is an increase of about 50

per cent over the preceding year.

Oven for Vacuum Work.

A high-temperature electric oven has been designed and built for use in the preparation of vacuum apparatus, such as quartz mercury

vapor lamps, which it is necessary to raise to a high temperature

during the process of evacuation. It is believed that the prolonged

heating which is now possible will also eliminate the moisture from

the vapor lamps used largely in many kinds of physical investigations, y Magnetic Field of Optical Magnet.

In studying the rotation of the plane of light waves which occurs when many substances are subjected to the presence of a magnetic

field, it has been found necessary to know the exact distribution of

force in the field produced by the Bureau's large electromagnet.

A preliminary study has been made under various working conditions (different pole pieces, different distances between the pole

pieces, different current strengths, etc.). The field of force along

the axis of the pole pieces has been explored with a bismuth spiral

(a device for measuring the strength of a magnet field), and the intensities plotted against the distance from the center of the field.

Curves have also been plotted showing the magnitude of the change

in the field strength caused by varying the distance between the pole

pieces and also by varying the current strength.

Supervision of the Customs Service Laboratories.

The important work of supervising the Treasury Department's

sugar-testing laboratories has been continued. The results obtained

by increasing the accuracy of the work have been highly gratifying. A mechanical system for controlling both the humidity "and the temperature pf the air has been installed in the New York laboratory

and a series of comparative sugar tests will be made simultaneously

with the Bureau's laboratory. The data secured by these tests should

be of great value and it is hoped will settle several vexatious questions regarding the necessity for temperature control in routine

sugar testing. Additional assistance has also been rendered the
74 REPORT OF DIRECTOR OP BUREAU OP STANDARDS.

Treasury Department with the object of making needed improvements in the equipment, personnel, and efficiency of its general cus- toms laboratories.

Polarimetric Tests of Raw Sugars and Molasses.

During the year 1,257 samples of raw sugars were tested. The

samples were mainly from the large ports of entry and the results

were used to check the accuracy of the customs laboratories. A number of samples of molasses were tested, the nature of the test and

the amount of work performed depending on the conditions under

which the sample was submitted.

Miscellaneous Polarimetric Testing.

A number of very pure samples of turpentines have been submitted

to the Bureau and their natural and magneto-optical rotations determined. It is hoped the data will aid in the identification of

turpentines. Other routine tests were made, such as polariscopes,

quartz control plates, and cover glasses for polariscope tubes.

Polariscope Tubes for Sugar Testing.

Practically no polariscopic apparatus is manufactured in the

United States. In an effort to make a beginning at overcoming this

very undesirable condition, the Bureau has designed a polariscope

tube. These tubes are used to contain the sugar solution while it is being read in the polariscope. The best European-made tubes are expensive, there is always delay in obtaining them, and they are inadequate in strength and scientific design. After an experimental

tube had been perfected at the Bureau, an American firm succeeded

in reproducing it so satisfactorily that the number of failures when

subjected to testing were less than the foreign-made tubes. The

Treasury Department has purchased these tubes in large numbers

and they are now on the general market, where they are fast displacing the imported article. There has thus been made available

to the American sugar industry a polariscope tube that is superior

in design, more durable, more costly to manufacture, and yet less ex- pensive than the European tube. Owing to the present difficulty of

securing apparatus from abroad, the sugar industry is suffering from

a lack of polariscopic apparatus, with the single exception of polariscope tubes. The Bureau hopes to succeed in establishing the manufacture of all polariscopic apparatus in this country.

Color Standards and Color Specification.

The need of scientifically valid and at the same time practicable

methods of specifying the color of materials is urgent in many industries as well as in scientific investigations. The demands made on the

Bureau for colorimetric tests and for information and advice relative

to color standards and color specification are frequent and persistent

and come from sources having such diverse interests as manufacturers, dealers, engineers, psychologists, opthamologists, dairymen,

biologists, chemists, and those who for lack of a better term may be

called the general public. For example, such requests have been re- ceived from the Navy Department, the Weather Bureau, the Bureau

of Chemistry, the Pennsylvania Railroad Co., the Automobile Club
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 75

of America, the National Dairy Union, the Society of Cotton Products Analysts, the Bellevue Hospital of New York City, the Eugenics

Record Office, and A^arious manufacturers, consulting engineers, and

scientific inA-estigators. The Bureau's correspondence shows that our

correspondents are interested in specifying the color of such substances as glass (signals, headlights, spectacles for e3"e protection),

petroleiun oil, cotton-seed oil, turpentine, rosin, paper, textiles (materials for uniforms, silks and felts for organization insignia, etc.)?

eggshells, egg yolks, butter, oleomargarine, dyes, water (as an index

of purity), solutions of various chemicals, portland cement, tobacco,

porcelain, flour, blood, and the human skin.

In many cases the need of reliable color specification is due to

purel_y commercial causes. The price of the commodity (cotton-seed

oil, for example) is determined by its color and a dispute as to correct

grading is a matter of dollars and cents between the buyer and seller.

In such cases the need of authoritative standards and methods of

measurement is keenly felt by dealers whose interests are involved.

On the other hand, there is also pronounced need of color standards

and methods of specification in various scientific investigations and

researches in physics, chemistry, biology, and psychology, where the

interest is often purely scientific and academic. Finally, in still other

cases color specification is a matter involving personal and public

safety, as in the instance of colored glass for eye protection, railway

and marine signal glasses, etc. In response to many of these varied demands during the year, the

Bm^eau has been able to perform tests and alford information and

advice as requested. On the other hand, owing either to lack of

assistance or to the xmdeveloped nature of the subject, it has been

impossible to conform to others. It will doubtless be possible to deal

satisfactorily with many of these latter cases at some future time, and

the applicants have been so informed. In this connection, it may be

pointed out that, compared with many other divisions of the Bureau's

work, this subject is new and unstandardized, being now in the formative stage. Much of the current work is, therefore, of a preliminary

and tentative nature. Assumptions must be tested; fundamental

facts,must be established by painstaking research; new instruments

must be designed and constructed; and methods of measurement must

be devised, tested, and S3^stematized. The important thing in this

division now is to lay secure foundations for the future, but, as is

shown in this report (see below), the current demands of the public

are largely met. although not in as complete and satisfactory a manner as is desirable. The demands made on the Bureau for this kind

of work would seem to justify the approj^riation of a special fund to

be used in ])utting it on a more satisfactory basis.

In the following paragraj^hs report is made on particular featm-es

of the year's work in regard to color siDecification, color standards,

and color grading.

Spectrophotometry.

The fundamental physical basis of color specification is spectrophotometrj^ Daylight is a mixture of many colored lights of all

hues—red, orange, yellow, green, blue, violet, and their transition

steps. For the sake of definiteness and accuracy in the subject, a
76 EEPOET OF DIEECTOK OF BUEEAU OF STANDAEDS.

colored light is specified by its wave length rather than by a color

name. A transparent substance which transmits light of certain

wave length more freely than others will generally appear colored,

the exact hue and tint being determined by the relative transmission

for the different wave lengths, while the shade is determined by the

total transmission. The task of spectrophotometry in this connection

is to detex'mine the transmission (ratio of transmitted light to incident light) for each wave length separately. The instrument for

making such determinations is called a spectrophotometer, being a combination of spectrometer (instrument for measuring wave

length) and photometer (instrument for measuring light intensity).

An accurate specification of spectral transmission (relative transmission for the different wave lengths) constitutes a complete and cer- tain specification of color, as a property of the substance.

During the year progress in spectrophotometry has been made in

the following particulars

Routine experimental methods have been improved and simplified

in a way to increase convenience and insure reliability.

By the design of a special slide rule a saving of about 50 per cent

in time of computing results has been accomplished with an accom- panying increase in convenience and reduction of mental fatigue.

The wave-length scale of the spectrophotometer has been recalibrated by a method independent of that used in its original calibration in 1913, and the first calibration closely verified.

Several satisfactory intercomparisons and countercheck experiments have been carried through in order to test the reliability and

accuracy of the methods used.

In order to have at hand a supply of color screens of known properties, the spectral transmission of a number of selected marked glass

samples has been determined and the samples and data systematically filed for future reference.

Although a great amount of work remains to be done and is outlined for the future, the s]3ectrophotometric work is now considered

to be well established and in good order. During the year reports on

spectrophotometric tests or investigations have been made for the

Pennsylvania Eailroad Co., the Automobile Club of America, Corning Glass Works, Society of Cotton Products Analysts, Florida Cotton Oil Co., National Dairy Union, Bureau of Chemistry, Weather

Bureau, and for Mr. Basset Jones, illuminating engineer. Tests were

also made for the photometric division of the Bureau of Standards,

and the Bureau of Plant Industry was afforded facilities and assist- ance in a spectrophotometric investigation of certain solutions of

interest in the study of chestnut blight. Detailed instructions for

calibrating the wave-length scale of the Konig-Martens spectrophotometer were supplied by request to the United States Food and

Drug Laboratory, New York City. Owing to lack of sufficient as- sistance, it has now become necessary to decline some routine spectrophotometric tests and refer the applicants to private testing

laboratories.

Color Specification by Means of the Rotator}' Dispersion of Quartz.

The many colored constituents of white light may be separated

and recombined in varying proportions by means of a property of
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 77

crystalline quartz known as rotatory dispersion. On this principle

there is constructed a colorimeter known as the quartz colorimeter.

Considerable time has been spent in critical study of this instrument

in the attempt to better adapt it to practical use. This work is still

in progress. A by-product of this study has been the suggestion of a novel method of comparing the candlepowers of lights of different

colors. This proposed method was definitely outlined by a member

of the Bureau staff at the meeting of the American Physical Society

in April, 1915.

Color of Cotton-Seed Oil.

The investigation of the color of cotton-seed oil mentioned in previous reports has been continued, although it has been greatly handicapped for lack of assistance. Progress has been made in the following particulars

:

The spectral transmission (see paragi'aph on " Spectrophotometry ") of a number of authentic samples of oil has been determined.

The' relative transmission for blue and yellow has been determined

(by means of a photometer and selected color glasses) for a number

of samples and the results considered as a function of color graded by

other methods. The determination of this relative transmission may

prove to be a satisfactory and practicable means of grading the oil. The permanency of the color under different conditions has been

studied. It is commonly known that the color is very fugitive when

exposed to light and air and that it fades more slowly in the dark.

Experiments this year have shown that the color is very permanent

even when exposed to direct sunlight, provided all air has been re- moved and the oil is kept sealed in vacuo. The establishment of this

fact is important as indicating the possibility of preserving standard

samples.

The color of samples of oil in different thicknesses has been read on

the Aron's chromoscope (a type of quartz colorimeter) to show the

relation between thickness and the scale readings of this instrument.

By invitation, the Bureau's expert in charge of this investigation

made a report on it at the Annual Convention of the Society of Cotton Products Analysts, Birmingham, Ala., in May, 1915, and this

report is being published in the Proceedings of that society.

Desiring to expedite this investigation and have it prosecuted more

rapidly than the Bureau's resources would permit, the Society of Cotton Products Analysts and the Interstate Cotton Seed Crushers' Association have provided about $1,700 to pay salaries of assistants to

carry on this investigation under the direction of this Bureau.

Accordingly, at the close of the year plans were adopted for the con- duct of such an investigation in the Bureau's laboratories. An as- sistant was selected and the work under this arrangement is now

well under way.

Method of Specifying a Color Limit for Oleomargarine.

At the request of the National Dairy Union, the Bureau has devised a method for specifying a color limit for oleomargarine. The

inception of this method was mentioned in last year's report. During the past year it has been developed and perfected and more

thoroughly tried out. This form of specification is believed to be

practicable as well as scientifically valid. The essential feature of
78 EEPOET OF DIBECTOE OF BUREAU OF STANDARDS.

the method is the specification of the color limit in terms of the

relative reflecting power for blue and yellow. For the sake of definiteness and precision, the wave lengths of the blue and yellow are

specified. The specification then reads : The diffuse reflecting power

for light of wave length Ji36 micromillimeters {blue) shall not he

less than — per cent of the diffuse reflecting power for light of wave

length 578 micromillimeters {yellow)^ the temperature of the sample

heing 70° F. The Bureau has designed and constructed a suitable

apparatus for measuring the ratio herein specified. This form of

specification was recommended to the National Dairy Union at its

conference at the Bureau June 2, 1915; and that organization has

adopted it, inserting " 70 " in the blank space before " per cent."

Investigation of Proposed Rosin Color Standards.

As mentioned in the report for 1914, a comparison of the colors

of natural rosins with their proposed glass standards for rosin colors

had been undertaken at the request of the Bureau of Chemistry,

Department of Agriculture, and was in progress at the close of the

fiscal year 1914. Final report on this investigation was made to the

Biu'eau of Chemistry on November 27, 1914. It summarized the

following conclusions:

1. The proposed glass standards do not match the same nominal

rosin grades (present trade standards) submitted. Some, indeed,

moi'e nearly match other grades. The proposed standards are generally (with one or two exceptions) paler than the present rosin

trade standards submitted.

2. The relative transmission for light of different colors is not

the same for the proposed standards as for the natural rosin. This

is an undesirable characteristic.

3. The color intervals between successive grades of the proposed

standards are not of uniform value.

Establishment of a Standard Method for Testing the Transparency

of Tracing Cloth.

The necessity of measuring in some way the transparency of

tracing cloth and semitransparent papers has been brought to the

Bureau's attention by the request of the Treasury Department, Navy

Department, Post Office Department, and several manufacturers and

dealers. In order to bring about uniformity and a general understanding among all interested parties, it has been necessary to formulate a standard method of test. The Bureau's method which has

been used in a tentative way for two or three years previously has

now been perfected and definitely adopted as a standard routine

test method. A circular statement was issued in February, 1915,

and sent to interested parties; and the method as outlined therein

has been approved by several qualified experts outside of the Bureau. The Navy Department, which formerly had a specification of

its own, has signified its intention of writing future specifications in

terms of this method of test. The essential feature of the method is the measurement of the

contrast between perfect black and perfect white as seen through

the tracing cloth. The Bureau has designed and constructed suitable apparatus for making this measurement.
REPORT OF DIKECTOR OE BUREAU OP STANDARDS. 79

The American Ceramic Society has also become interested in this

method as affording a means of measuring the translucency of porcelain. By invitation the Bureau's expert on this subject described

the method to that society at its annual convention at Detroit in

February, 1915, and his paper is being published in the Transactions

of that society.

Study of Method of Measuring the Turbidity of Spinal Fluids.

At the request of the Psychiatric Institute of the State Hospitals

of New York, a study of the turbidimeter was made to determine its

usefulness in measuring the turbidity of spinal fluids. The study of

this serum is of importance in the diagnosis of diseases of the brain.

The results obtained with the preliminary instrument show that it

is entirely applicable, and a representative of the Bureau has assisted

the institute in designing apparatus to be used in this work.

Study of the Properties of Fog at Sea.

The great influence of fog upon the safety of vessels at sea makes

a scientific investigation of fog desirable.

A preliminary investigation of the properties of fog at sea was

made in cooperation with the ice patrol of the Coast Guard Service on

the May cruise of the Seneca. A study was made of the number of

nuclei present in the sea atmosphere. Nuclei are small " dust particles," always present in the air, upon which the water vapor condenses. The number of these condensation nuclei, or the nucleation, is a most important characteristic of the atmosphere in relation to fog. The amount of liquid in the fog particles was also

studied.

Information Furnished on Optical Subjects.

Information relative to such subjects as color specification, transparency, translucency, turbidity, and interferometry (methods of

measurement in terms of the wave length of light) has been supplied on request to many applicants, sometimes by correspondence

and again by personal conference. Among those served in this way

were the Navy Department, the Department of Agriculture, the

Pennsylvania Railroad Co., the General Electric Co., the Waltham

Watch Co., the A. D. Little Co., of Boston, Bellevue Hospital, of

New York City, and others.

Investigation of the Commonly Found Errors in Photographic

Lenses.

Methods have been developed for the measurement of the errors which interfere with good definition near the center of the field of

view. Measurements have been made on the principal types of

commercial lenses for four different colors and for zones extending

from the center to the edge of the lens.

This investigation in conjunction with previous ones gives a numerical measurement of the quality of a lens. The results of this investigation are being prepared for publication.

Speeds of Photographic Shutters.

Preliminary determinations of the speeds of photographic shutters

have shown that many shutters are erroneously marked and, there-
80 EEPOET OF DIRECTOR OF BUREAU OF STANDARDS.

fore, an investigation of their speeds and efficiencies has been started.

As an example, several shutters gave an almost uniform speed of

1/40= when set at 1/25% 1/50= and 1/100=.

Standard Lenses for Opticians' Trial Sets.

An investigation of the methods of standardization of opticians'

trial sets is being carried out in order to eliminate some of the endless

confusion arising from the numerous errors in trial set standards.

Two sets submitted by one of the leading manufacturers are now being standardized and will be used by them as primary standards.

Testing Optical Systems.

The testing of optical systems has been done largely for the different departments of the Government. These tests embrace various

types of optical instruments, including photographic lenses, searchlight mirrors, binoculars, telescopes, projection lenses, submarine periscopes, and gun sights.

A marked increase in light transmission of certain optical instruments has been noted since last year. In some cases this increase is more than 40 per cent.

Refractive Indices.

The extent to which light is deviated from a direct course when

passing through a transparent substance is defined as the refractive

index of the substance.

Kefractive index determinations have been made of glass and va- rious materials as requested for tests. Also some standard test plates

have been furnished to manufacturers for calibration of their instruments for measuring refractive indices.

Information Furnished as to Optical Instruments.

Many requests have been received for information and advice con- cerning optical instruments.

A comparative investigation of the optical parts of motion-picture

machines was made for the purpose of selecting the most suitable

machine from those submitted as samples in connection with the purchase of such machines by one of the departments.

Many have applied for advice regarding the practicability of projected optical systems, and much assistance has been rendered in this

direction. Simple formulse for spectacle lenses free from astigmatism for oblique rays were developed, at the request of one optical

firm.

Considerable time has been devoted to consultation work with

the various departments of the Government, as well as with the different divisions of this Bureau with reference to the design, specification, testing, and use of optical systems. Also, data have been furnished which enabled some optical systems to be repaired in this

country where formerly repair parts could only be obtained abroad.

Radiometry.

In many physical, chemical, and physiological investigations it

is of great importance to know the behavior of substances when subjected to stimuli of radiant power, light, and heat rays; that is, radiant energy of all wave lengths, whether visible or invisible to
BEPOBT OF DIRECTOR OF BUREAU OF STANDARDS. 81

the eye. During the past year the Bureau has continued its investigation in connection with the improvement of instruments for meas- uring radiant energy, especially instruments for measuring radiant

energy in absolute value. Important advances were made in shielding the galvanometer from external magnetic disturbances and

thereby improving the reliability of the radiometric measurements.

The design of galvanometer coils was also investigated. Coils

wound in 1, 2, or 3 sections of graded wire were compared with a

set of three standard coils, and the magnetic force exerted by them

was thus determined. As a result of this investigation, a coil, wound

empirically Avith a single grade of wire, was found which is as

elRcient as a coil wound according to theory and having three sec- tions of graded wire. Furthermore, a coil which was empirically

wound was found which was about 20 per cent more efficient than a

coil having the same resistance but wound according to theory. In

addition to magnetic shielding and the design of the coils, further

attempts in improving the galvanometer are in progress. The results

of this investigation are ready for publication.

Nocturnal Radiation Measurements.

Nocturnal radiation is usually a loss of heat from terrestrial substances into space. This has a profound influence upon terrestrial

temperatures and, hence, upon vegetation. During the past year

instruments were constructed for the United States Weather Bureau

for investigating this loss of radiation into space, the direct practical application being the question of the cause of frosts upon certain

mountain sides which are covered with fruit trees. Radiometric Outfit for Physiological Work.

Radiometric instruments, including galvanometer, thermopile, etc., are in the process of construction for the United States Public Health

Service. This apparatus is to be used in measuring light stimuli in

connection Avith investigations of vocational diseases.

Glasses Which are Opaque to Infra-Red Rays.

There has been considerable agitation of the question of the protection of the eyes of workmen exposed to the intense infra-red

radiations from red-hot furnaces and from the intense luminous

radiations from arc lamps, etc. Glass manufacturers are actively

engaged in the production of spectacle glasses which absorb all the

infra-red rays, but have a high transmission in the visible spectrum.

During the past six years and especially during the past year vari- ous glasses have been examined for their transparency in the infrared, and from the results obtained the Bureau is in a position to give

authoritative information relative to general cases of eye protection

by means of colored glasses.

In this connection, it is relevant to repeat the statement made in

last year's report regarding the necessity of carrying on investigations of the properties of materials, even though the immediate

practical application of the data may not be apparent. In that re- port ca_ses were cited where the data obtained dicl not appear to have

immediate application. The present case of the application of data,

obtained some years ago, on the transmission of colored glasses is a

10739°—15 6
82 KEPOET OF DIRECTOR OF BUREAU OF STANDARDS.

further illustration of the importance of carrying on investigations

of the properties of materials, even though an immediate application can not be made of the data so obtained.

The Stefan-Boltzmann Constant.

The coefficient of total radiation from a perfectly radiating body,

commonly called the Stefan-Boltzmann constant, was thoroughly investigated during the past year by means of an improved radiometer

applicable for evaluating radiant energy in absolute measure. The

investigation was made imder various conditions as to atmospheric

humidity, blackness of the radiator, different kinds of receivers, etc. The value of the coefficient of total radiation as determined by this

method is (7=5.74X10""^^ watt cm"~^ deg~*. The investigations made

during the past twenty years, using different methods, were subjected to rigorous analysis. Corrections were made for atmospheric

absorption, and it was then found that all the reliable investigations

give values which are close to (y=5.7. The data obtained in this

investigation have been assembled into a paper which is ready for

publication. The first part of this paper deals with instruments for

evaluating radiant power in absohite measure; the second part of

the paper gives an analysis of all the data available on the coefficient

of total radifition, as well as subsidiary data on atmospheric absorption, etc.

Measurements on the Radiation from Stars.

During the past 47 years numerous attempts have been made to

measure the heat received from stars. In last year's report attention

was called to the perfection of a minute thermocouple of bismuthplatinum in a vacuum maintained by means of metallic calcium.

During the past year a number of these stellar thermocouples were

compared in the laboratory and also in connection with a 3-foot

reflecting telescope at the Lick Observatory, Mount Hamilton, Cal.

The instruments proved to be satisfactory. Measurements were made

on 112 celestial objects, including 105 stars, the bright and dark bands

of Jupiter, the rings of Saturn, etc. Stars to the 6.7 magnitude were

measured, and the whole research constitutes the first really success- ful measurement of stellar radiation by means of instruments of this

type. The data obtained have already found useful application and

it is hoped that further work may be continued. With this end in

view, the above mentioned investigation of the efficiency of galvanometer coils was made ; further work is in progress on increasing the

sensitivity of the galvanometer and the thermocouples. Recently

two papers have been published by astronomers who used the above

mentioned radiometric measurements in discussing the probable temperature of stars.

5. CHEMISTRY.

Standard Analyzed Samples.

The demand for the standard samples that are under the control

of the chemistry division has shown a good increase of almost 200

over the previous year. A part of this increase arises from the
EEPOKT OF DIRECTOR OF BUREAU OF STANDARDS. 83

abnormal demands of the last four months on the part of certain

industries, growing out of the European war. The worth of the Bureau's series of analyzed standard samples,

and the need of standards of analysis of the highest purity to those

engaged in industrial pursuits, as well as to those engaged in teaching and studying, is so well established that the maintenance and

increase of this series of (at present) 38 samples should be assured

by a moderate fund continued from year to year. This fund should

be available for salaries and travel, as well as for the purchase and

preparation of materials, apparatus, and appliances. It is believed

that an annual appropriation of $4,000 or $5,000 will cover expenses

of every kind in connection with these standard samples.

No new samples have been added to the existing series, but the

Alabama iron, referred to in the last report as iron E, has been subjected to analysis and will be issued to the public as soon as certain

discrepancies are reconciled. An interesting development of the

analysis of this iron is the discovery that it has an unusually high

vanadium content of about 0.08 per cent. The inquiry at once suggested itself: Is this normal or accidental? If normal, it would

mean that the Alabama ore, coke, or fliix used in making this particular iron were, one or more, appreciably vanadiferous. Tests instituted by the chief chemist of the Tennessee Coal & Iron Co.,

at the suggestion of the Bureau, show as far as they go that the

Alabama ores and coke, but not the limestone flux, do carry vanadium,

but in amounts less than is shown by the pig iron E. The matter

has undoubtedly some commercial significance and should be investigated further by those interested.

It has not been possible as yet to devise a method by which a cast

brass can be produced of composition so uniform throughout the

ingot as to obviate the need of mixing after the mass has been reduced

to chips. The method of " atomizing " a pot of molten metal by

means of superheated steam seems well adapted for relatively low

melting alloys, like type metal and babbitts, but has not been success- fully applied yet to brasses. Even with the white alloys, the yield

of grains of suitable size is rather low (30 to 40 per cent), so that an

inconveniently large mass must be melted in one lot in order to provide

the needed few hundred pounds of finished product. In cooperation

with the Bureau, experiments will be continued by representatives of

the National Lead Co. and the New Jersey Zinc Co. in the hope that

the process can be improved and made applicable to the higher melting alloys.

Chemical Tests of an Umpire Nature.

The Bureau is frequently requested to determine for commercial

firms, or to help them to determine, the composition of a material

which they wish to employ as an analytical standard in their own

work or concerning the composition of which there is seemingly

irreconcilable dispute. Such requests usually involve more or less

research and are refused unless it is shown that their own or commercial analysts are imable to afford the information sought. If shown,

however, it is held to be eminently proper to give all the aid possible.

Some recent tests of this nature have been on the manganese content of a certain steel standard ; the silicon content of certain steels

;
84 BEPORT OE DIRECTOR OF BUREAU OF STANDARDS.

the sulphur content of certain irons; the lead content of a western

standard lead ore; and the correct determination of cadmium in

spelter.

Usually the work done at the Bureau has been accepted as conclusive by those interested, either as to the true composition or as to the

method used. The reputation of the Bureau as a court of resort in

many lines of chemical analysis is high, and it should be maintained

by increasing the number of men assignable to analytical research of

a high order and adequately recognizing the ability of those who

prove themselves most worthy.

Investigation of the Methods Relating to the Analysis of Irons and

Steels.

The large amount of iron and steel testing called for and the

large number of new methods of analysis, or modifications of old

methods that are put forth, make it imperative to devote perhaps

more time to trying out certain of these methods than is the case in

any other branch of the Bureau's analytical work. Such work may

lead to modifications of the methods employed by the Bureau, but

as a rule the knowledge acquired from it, while of value, is not of a kind to justify publication. Examples of this kind that have been

handled are, precipitation of tungsten as the pentoside by stannous

chloride ; the influence of vanadium on the titration of iron by potassium dichromate; the titration of titanium solutions by ferric chloride; the titration of ferric chloride by sodium thiosulphate ; the

reduction of compounds of chromium, vanadium, molybdenum, and

tungsten in the zinc reductor, and, the titration of iron by stannous

chloride. A new method of determining vanadium and chromium

in the presence of each other is now being studied.

Preparation of Iron Carbon Alloys.

The preparation of pure electrolytic iron and of alloys of iron and

carbon begun in the previous year has been actively continued in co- operation with the Division of Metallurgy. A paper embodying

the results of this research is nearly ready. The technique neces- sary for such investigations, involving the selection of suitable

furnaces, crucibles, electrolytic baths, and related questions, has

been worked out for this and similar future investigations. _A

series of alloj^s with not to exceed 0.02 per cent of total impurities

has been made for use in exploring the thermal equilibrium diagram

for the iron-carbon system. Preparation of large ingots by similar

methods for investigating other physical properties is under way.

High-Temperature Carbon Combustions.

The experimental work on high-temperature carbon combustions,

referred to in the last report, has been completed and the results are being prepared for publication. Suitable high-temperature apparatus has been devised for making combustions at a temperature

above the melting point of iron oxide, so that carbon retained by the

oxide may be liberated. The method has been applied to a wide

range of the Bureau's standard irons and steel samples, with the

result that the certificate values are in most cases confirmed, the

maximum deviation by the new method being 0.02 per cent carbon

(higher) in one or two instances.
EEPOKT OP DIEECTOE OF BUREAU OP STANDARDS. 85

Test o£ Surface Combustion Furnace.

Much work has been done on a furnace for high combustion and

a paper on the subject is about read}^ for publication.. The work

shows that temperatures in excess of 1700° C. can be obtained readily

with gas of not over 620 B. t. u. heating power; that the best ratio

of air to gas is in the neighborhood of 5.5 to 1, and that small

deviations from this ratio exert marked effects on the maximum

temperature attained. Further work with refractories that will

permit of attaining higher temperatures is contemplated.

Ladle Test Ingot Investigation.

The first stage of the ladle test ingot investigation is completed

and has been reported upon to the American Society for Testing

Materials. The conclusion reached is that no geometrical shape of

test piece can be chosen to give a sound ingot unless the steel has

had previous suitable metalliirgical treatment to eliminate the harmful effect of occluded or dissolved gases, oxides, and slags. The next

stage of the work will be an endeavor to find a simple and proper

treatment to insure sound ingots.

Standard Methods for the Analysis of Pig Iron and Iron Castings

for Export.

The chief chemist of the Bureau, as the American representative

on a subcommittee of the International Society for Testing Materials, has prepared, with the assistance of other experts, proposed

methods for the analysis of pig iron and iron castings for export,

which will appear in this year's Year Book of the American Society

for Testing Materials as tentative methods for use in this country,

subject to final action by the society a year hence.

Standard Methods for the Analysis of Steels.

In cooperation with the American Society for Testing Materials,

the Bureau has taken a leading part in compiling methods for the

analysis of plain and alloy steels. The first of these specifications

has received the approval of the society and the second is before the

society for further action.

Tests on Steel for Other Divisions of the Bureau.

Many analytical tests of a more or less extended nature have been

made in cooperation with other divisions of the Bureau, among which

may be specially mentioned those on rail failures.

Sampling and Analysis of Coal.

In cooperation with the committee on coal analysis of the American Chemical Society, acting in conjunction with a similar committee

of the American Society for Testing Materials, the Bureau has

helped in the revision of methods for the sampling and analysis of

coal. These methods are now before the latter society for a year's

consideration before the final vote is taken.

Chemical Work in Connection with Paper.

The first of the work on paper pulp is nearing completion. The

chemical constants of the more important pulps have been deter-
86 EEPORT OF DIEECTOE OF BUEEAU OF STANDAEDS.

mined, and the resistance of the pulps to hydrolizing and oxidizing

agents has been ascertained. The eifect of esterification has been

studied. The observations made will assist in a later study of the

effect of filling and sizing agents upon the life of paper.

The study of changes occurring in ground wood pulp under the

influence of active oxygen, sunlight, and heat has been completed.

This is of importance in determining the effect of residues of lignin

in paper pulps.

Some information has been gained on the determination of sizing

agents.

Textiles.

The chemical division has made numerous determinations of moisture in fabrics for the textile section of the Bureau in an effort to

substitute a bone-dry basis for the air conditioning of textiles. A

large amount of routine examination of fabrics has also been con- ducted for the textile section.

Distinguishing Sisal and Manila.

An attempt has been made to find some means by the use of stains

of distinguishing manila from sisal in cordages, but with only partial

success, since such distinctions as have been noted are not applicable

to both coarse and fine varieties. The situation has been put before

manufacturers of cordage in the hope that some of them may be able

to follow up the clues indicated by the Bureau.

Lubricating and Transformer Oils.

Considerable time has been spent in endeavoring to improve the

" carbonization " test and to connect the carbonization factor with the

behavior of oils imder other conditions. The results of this investigation are now being prepared for publication. The test, similar to

that of Kissling, seems to give satisfaction with gas-engine oils.

A leading oil refinery used part of one of the Bureau's reports as an advertisement and quite recently the Bureau was informed that

the oil purchased on its recommendation by the Post Office Department is entirely satisfactory.

Data on the carbonization of other classes of oils are being ac- cumulated.

Gum Arabic.

A research begun in the early daj^s of the Bureau's chemical activities on methods for detecting and determining gum arable has been

renewed. A new method was devised, but has been withheld until

more information can be gathered as to one or two points. This work

was taken up in connection with Government purchases.

Articles Involving Danger to Life or Property.

Many reports and opinions covering the chemical composition of a wide range of substances supposed to involve fire or life risk have

been prepared for the Steamboat-Inspection Service to serve as a

basis for its decisions regarding the acceptance of the articles in

question as freight by passenger-carrying vessels. In most cases no

laboratory work was necessary ; in others, simple tests sufficed, while
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 87

the still pending question of ferrosilicon may eventually lead to an

experimental research.

Some of the more important subjects upon which the Bureau has

been requested to report with reference to safety are ferrosilicon,

porosity of fillers used in acetylene cylinders, thermit, polishing

cloth, and slickers.

Chemical Analysis of Rubber.

Considerable progress has been made in studying methods of chemical analysis for rubber goods. A paper on the determination of

total sulphur in rubber is in print and another on the determination

of barium sulphate and carbonate is nearly completed. Since many

specifications permit the use of barium sulphate as a mineral filler

without having the sulphur which it contains considered as part

of the total sulphur, it is necessary to be able to determine this constituent in the presence of any possible disturbing factor.

Cooperative work on rubber has been continued with two organizations, namely, the American Chemical Society and the Joint Rubber Insulation Committee. In cooperation with the latter body, the

Bureau has devoted much effort to the development of a more satisfactory method for the determination of fillers in rubber.

The rubber exjDerimental mill at the Bureau has been in successful

operation and has proved of much assistance in connection with the

above investigation. Its use has revealed the fact that the Bureau's

method for determining the amount of oil substitutes present in rubber compounds yields low results.

A tubing machine and a steam vulcanizer have been added to the

existing equipment and with these the subject of rubber laboratory

tubing will be investigated. The Bureau has taken up this subject

of tubing with several manufacturers and as a result three new

compounds are now being tried out in actual service. It is hoped

that these compounds will be more satisfactory than those that have

been obtainable from the schedule of the General Supply Committee.

A third edition of Circular No. 38, on the Testing of Rubber Goods,

has been issued, very much enlarged by the addition of new matter,

including the chemical methods in use at the Bureau.

Printing Ink.

Circular No. 53, on The Composition, Properties, and Testing of

Printing Inks, has been issued and is in frequent demand. Additional information is being gathered for the purpose of extending

the scope of this circular. Very little has been published heretofore

on the subject.

Determination of Oil and Resin in Varnish.

The Bureau has been studying the question of the determination

of oil and resin in varnish and the results obtained show a decided

advance in this dilficult subject. A paper dealing with this investigation is now in course of preparation.

Soap.

Practically all branches of the Government service have been invited to cooperate with the chemistry division of the Bureau in pre-
88 EEPORT OP DIEECTOK OP BUEEAU OP STANDARDS,

paring specifications for soap materials, with the view of reducing

the number of varieties now bought and of malring it easier for manufacturers to bid in connection with the annual contracts. There has

been prepared the first draft of a circular of information on soap,

which is now in the hands of representatives of the various branches

of the Government service and numerous manufacturers for criticism.

Paint Investigation.

The question of specifications for materials used in paints and

varnishes has always occupied a considerable share of the attention

of the chemical division. The preparation of specifications for paint

materials is an important field of work and much thought has been

devoted to this subject in cooperation with the American Society

for Testing Materials. Other subjects handled during the past year

in cooperation with the same society have been the revision of specifications for purity of raw linseed oil from North American seed,

new specifications for the purity of boiled linseed oil from North

American seed, the purity of raw Chinese wood oil, turpentine, and

the definition of terms used in paint specifications. It is believed that

this work will be of material assistance to the paint and varnish industries, as well as to the usei's of these materials. The Bureau has

also cooperated in preparing methods for the analysis of white pigments, which are now being considered for adoption by the American

Society for Testing Materials. These methods of analysis were developed almost entirely in this Bureau and a large amount of work

incident to the preparation of the specifications and definitions was

done by the chemistry division.

Considerable work has been done during the past year in connection with an exposure test of certain commercial white paints on wood. This investigation is still in progress.

Gas Analysis.

In furtherance of the Bureau's efforts to improve and standardize

methods of gas testing, a comprehensive investigation of the leadacetate test for hydrogen sulphide in gas was carried out and the

results have been published as Technologic Paper No. 41. The numerous factors which affect the delicacy and reproducibility of this test,

which is of importance in testing the purity of satisfactory gas supplies, have been investigated and a standard procedure and apparatus

for carrying out the test have been recommended. It is of interest

to note that the American Gas Institute has adopted practically the

recommendation of the technologic paper for the gas analyst's handbook, which is in preparation.

An exhaustive study of methods and apparatus for exact and commercial gas analysis has been begun. Several new forms of apjoaratus for gas analysis and for use in closely related problems have been

devised and are now under construction, including notably a weight

burette with very accurate compensator for temperature changes and

a balance for determining the specific gravity of small amounts of

gas. A very complete bibliography of the literature on gas analysis

has been prepared. This bibliography, wliich contains more than

2,000 references, is arranged in duplicate by subject and by author

and includes many abstracts of the articles.
REPOKT OF DIRECTOR OF BUREAU OF STANDARDS. 89

Preparation and Testing of Gases of High Purity.

The Bureau has been engaged for some time in the preparation of

apparatus and the devising of means for maldng in a high state of

purity the various gases which are tlae constituents of commercial

gas supplies. The preparation of these gases and the determination

of their physical and chemical properties will form an important

part of the laboratory investigation for a considerable time to come,

being preliminary to the determination of the properties of their

mixtures with each other as they occur in fuel and illuminating gases.

Hydrogen has been prepared by electrolysis and by the action of

sulphuric acid on zinc and of hydrone on water. A generator working on the Kipp principle, but possessing a number of novel features,

has been designed and constructed for use in generating hydrogen

from zinc and acid. This generator can be evacuated completely

before filling with acid and air-free acid can be introduced without

danger of contamination. The space above the liquid in the reser- voir is at all times filled with hydrogen of the highest purity, thus

preventing the contamination by air of the hydrogen generated. A

very satisfactory electrolytic generator and gas-purifying train has

been constructed. Several samples of the hydrogen from the different sources mentioned have been tested by chemical analysis, by determining the density of the gas by weighing, and by intercomparison in

the gas interferometer. The application of the interferometer in gas

analysis problems is being studied, particularly as offering a valuable

means for the accurate testing of the pure gases that are to be

prepared.

Te determination of the heat of combustion of hydrogen has been

undertaken by the chemical division in cooperation with the division

on heat and thermometry. Satisfactory progress has been made on

the preliminary series with this gas and it is planned to continue the

work, both with the hydrogen and with the other pure gases as they

are prepared. The methods developed on the pure gases can then be

applied on synthetic mixtures of known composition. The calculation of the heating value of gas mixtures from results of analysis is

very desirable, but until much progress shall have been made in the

study of gas analysis, as well as in the study of calorimetric constants,

there is little hope of making application of this method of computation for accurate work.

A number of pieces of apparatus worthy of mention have been

designed for use in the laboratory work in connection with gas investigations. There has been designed, and constructed in the instrument shop of the Bureau, a gas holder of 14 liters capacity which is

well adapted»to storing gases of high purity without contamination,

since the gas is retained in contact only with glass, steel, and mercury. Other pieces of apparatus that have been devised are an

apparatus for the determination of svilphur in gas, possessing a marked advantage over that previously used; several new forms of

gas-washing apparatus, which have been found very convenient in

gas analytical work ; and a new form of pipette for gas analysis work,

intended to give rapid and complete absorption. A thermostat has

also been built which will be used first in connection with the determination of gas density and later for general work in the laboratory. This apparatus operates very satisfactorily, the stirring and
90 EEPOET OF DIRECTOR OF BUREAU OF STANDARDS.

regulating devices being so efficient that the temperature is maintained constant within 0.005° C.

Control of Purity of the Bureau's Oxygen Supply.

The oxygen supply of the Bureau has been examined for possible

impurities a number of times and tests have been made on it to

determine the amount of combustible impurities which would vitiate

the results obtained in exact calorimetry in which this oxygen has

been used.

Colorimetric Determination of Acetylene.

Considerable attention has been given during the past year to an

investigation of the colorimetric method for the determination of

acetylene, suggested by work done in the previous year. An account

of the earliest work on this general problem was published in December, 1914, in the Journal of the American Chemical Society as "A

quantitative test for water by the use of the acetylene-cuprous chloride reaction." The quantitative application of the method for the

determination of acetylene proved to be very satisfactory, as results

indicate a possible accuracy of about 0.02 mg. C2H2, but the effort

which was made to apply the method to the quantitative determination of very small amounts of water brought to light two difficulties

which seemed insurmountable, namely, (1) the difficulty of removal

of acetylene from the calcium carbide which was used, and (2) the

incompleteness of the evolution of acetylene from the water in the

samples taken. A paper embodying the results of this research is

nearly ready for publication.

Determination of Phosphorus and Sulphur in Calcium Carbide.

A new method for the determination of phosphorus and sulphur

in calcium carbide has been developed, but the results of the investigation have not yet been prepared for publication.

Distillation of Liquid Air in a Magnetic Field.

A brief article was prepared and published in the Journal of the

American Chemical Society on experiments made two years ago on

the distillation of liquid air in a magnetic field. The object of the

research was to ascertain if distillation in the magnetic field would

have a favorable effect on the separation of the constituents of the

air ; apparently some advantage does accrue, but not a great one.

Preparation of Naphthalene.

A new lot of naphthalene was prepared by the chemistry division

for use as a standard material for the calibration ot calorimeters.

Fifty pounds of crude material was purified by crystallization with

subsequent sublimation in vacuo. Bituminous Materials.

A careful study has been made of the equipment and methods for

testing bituminous materials in the laboratories of manufacturers,

consumers, public institutions, and others, and as a result the equipment of the laboratory of the Bureau dealing with these materials

has been brought more up to date and important modifications have
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 91

been made in the methods in use for routine testing. In connection

with bituminous paints, it has been found tliat the asphalt used is

fluxed not only with the common fluxes, asphaltum or paraffin oils,

but also Avith rosin, pine oil, stearine pitch, fats, and fatty acids.

Phosphate Rock Analysis.

Very little, if any, progress has been made on the problems relating

to the analysis of phosphate rock. It is very desirable that this work

be carried to completion in order to render available the large

amount of data that has already been obtained on this subject.

The Chemistry of Electrotyping.

The study begun over a year ago to give electrotypers much needed

information for the control of their solutions has been prosecuted

actively, mainly by analyzing a large number of samples received

from commercial electrotyping plants. The primary object of these

analyses was to gain a Imowledge of the conditions now prevailing in

the industry and of the problems in need of study.

In addition an efi^ort has been made to get into closer touch with

electrotypers' organizations, both of employers and employees, by

means of informal interviews, wherein the nature and advantages of

scientific work in this field are pointed out. In general these bodies

have shown a marked interest in such work. A brief circular (Circular No. 52), giving simple methods of analysis of copper electrotyping solutions, has been issued. A revision of this circular is now

in preparation which will contain a summary of the information

that is available in this field and an explanation of the simple electrical and chemical terms.

In cooperation with representatives of the electrotyping industry

and with certain other divisions of the Bureau, the chemistry division

has undertaken the following researches in connection Avith this subject: The determination of the density of copper sulphate-sulphuric

acid solutions; the determination of the conductivity of copper sulphate-siilphuric acid solutions; a study of the effect of the conditions of deposition upon the hardness, tensile strength, and structure

of electrolytically deposited copper ; and the possibility of the application of cobalt deposition to electrotyping.

Other problems in urgent need of study for the benefit of the el.ee- trotyper's industry are the composition and physical properties of

ozocerite and other materials used in molding wax, the composition

and physical properties of graphites suitable for electrotyping, and

the operation of nickel electrotyping baths. The latter might well

be included in a study of nickel-plating baths in general.

Investigations Relating to Electroplating.

The advance thus far made toward the study of electroplating

has been of interest primarily to electrotypers. The American Electroplaters' Society recently requested the Bureau to cooperate with

them in a study of plating operations. Such a study would involve

problems in electrochemistry, analytical chemistry, and metallography. It is impossible, however, for the present limited force to

make rapid progress in the electrotyping field, let alone that of
92 EEPOET OF DIEECTOE OF BUEEAU OF STANDAEDS.

electroplating. It is recommended, therefore, that a special fund be

secured, if possible, to be devoted to the study of electrotyjoing and

electroplating problems.

Standard Cells.

Progress on the investigations having to do with standards of electromotive force has not been on the whole as satisfactory as could be

desired, because of frequent interruptions made necessary by other

work. A few cells have been set up with mercurous sulphate made

by the alternating current, which gives very constant and reproducible results. Twenty kilograms of cadmium sulphate have been

purified and this material will be used in setting up the large series

of cells necessary to test the alternating current x^roduct. Some

20 additional samples of mercurous sulphate have been made under

conditions where each of the factors have been varied for the purpose

of determining the best conditions of preparation, although it is

already fairly well Imown just what constitutes satisfactory conditions. This preparative work, which can be almost indefinitely ex- tended, has been temporarily abandoned and the setting up of cells

with material made under conditions that are satisfactory will give

results in the immediate future. Unsaturated cells have been set up

for the first time for the use of the Bureau's laboratories, and they

show excellent behavior.

Chemical Work in Connection with Refrigeration Constants.

Progress in work on the constants of materials used in refrigeration has been satisfactory. The purification of materials is well in

hand and has been keeping pace with the requirements of those interests using them for physical measurements.

The subject of ammonia has been 0C3up3dng a considerable share

of the attention of the chemistry division. An apparatus with many

new features has been devised for the fractional distillation and,

possiblj'-, the sublimation of substances at low temperatures. In cooperation with the optical division, the use of the characteristic absorption bands of pyridine in the ultra-violet has been tested, using aquaammonia. The indications are that this test is sensitive to 3 parts

in 1,000,000. Further work is necessary and, if possible, a similar

method will be applied for the detection of acetonitrile in ammonia.

Carbon compounds as such are being tested for by combustion of the

gaseous ammonia in oxygen and estimation of the carbon dioxide

formed.

While it has been possible to pick out the best commercial ammonia

as a starting point for preparative work, and perhaps for general

chemical work where gaseous ammonia may be used, it will be neces- sary to do some additional work before rational specifications for the

material can be developed. Eesults obtained from the investigation

being conducted on gas formation will have a considerable bearing

on these specifications.

The cause of formation of noncondensing gases has been attacked

from all the various points that have suggested themselves, which

makes the work rather extensive in scope. Work on the following

more or less independent phases of the problem is under way and
REPORT OP DIRECTOR OP BUREAU OP STANDARDS. 93

some progress has been made on each : The sohibility of gases in

liquid ammonia; decomposition of ammonia under working conditions of both the absorption and compression plants, which are to

be simulated in an apparatus for that purpose; gas formation under

working conditions in the plant of the Bureau Avith special reference

to the locality of formation and behavior of the gas in the system;

and a study of the quantity of the gas formed and the amount of

ammonia lost in purging in the commercial plants of Washington

and Baltimore.

Sodium chloride has been purified for use in making brines for the

density and specific heat determinations. Calcium and magnesium

chlorides that are to be used for similar purposes have been analyzed.

Conductivity of Electrolytic Standards.

Some progress has been made on the investigation of the absolute

measurement of electrolytic resistance. It is desirable that more

attention be given to this important problem, since the need for

research on this subject is becoming more and more evident.

Platinum Investigation.

It is not necessary to renew in its entirety the suggestion of last

year for the transfer of the Mint's platinum to the Bureau of Standards, since the Director of the Mint lias undertaken, as soon as arrangements can be made, to provide Government laboratories

with platinum utensils derived from the platinum which accumulates during refining operations in the Mint. There will be

needed, however, an advanced analyst to make a specialty of the

analytical chemistry of the platinum metals, for upon such work

will depend in large measure the value of the advice this Bureau can

give to the Mint in reference to the proper specifications for different

forms of finished Avare. The services of a very competent chemist

will be needed for some years, working in cooperation with certain

other divisions of the Bureau, on the determination of the constants

of the metals of the platinum group and of their alloys.

Research of the Methods and Standards Employed in Volumetric

Analysis.

A study of the methods and standards employed in volumetric

analysis is of fundamental importance for exact work in almost all

lines of chemical analysis. The need for this research is even more

pressing than a year ago, and work shoidd be undertaken on this important problem as soon as possible. The services of a chemist qualified in physical and analytical chemistry will first be needed and with

the advancement of the work additional help will become necessary.

Chemical Testing.

The routine testing in the chemical division during the past year

has increased very largely in consequence of taking over the work

of the contracts laboratory of the Bureau of Chemistry. However,

the increase is not altogether due to this cause, since there has also

been a noticeable increase due to improved methods in the purchasing

of Government supplies.
94 EEPOET OF DIEECTOE OF BUEEAU OF STANDAEDS,

More than 12,500 tests of materials were made by the chemical

division during the year. They involved the following materials:

Ferrous metals (irons and steels) , 981 ; coated metals, 641 ; nonferrous metals and alloys, 1,106 ; material from electrotyping baths,

398; cement materials, 1,296; coal tars and asphalts, 533; saturated

felts, 258 ; burlap and building paper, 211 ; linseed oil and turpentine, 541; driers, 313; varnish and shellac, 610; red lead, 184; white

lead, 284 ; putty, 186 ; graphite paint, 249 ; miscellaneous paint colors,

472 ; greases, 51 ; soaps, nondrying oils, and metal polishes, 498 ; oils

(lubricating), 373; inks (printing), 28; ink materials other than for

printing, 474; flax packing, 24; asbestos, 39; paper, 2,267; rubber,

256; rope, 5; wax (sealing), 30; wools, 39; textile materials, 49; miscellaneous materials, 410.

The Bureau's chemical tests were made for about 70 Government

bureaus and establishments, including practically every executive

department, as follows: Agriculture, 24; Commerce, 906; Interior,

93 ; Labor, 44 ;_ Navy, 302 ; Post Office, 564 ; State, 1 ; Treasury, 495

;

War, 403 ; United States committees and commissions, 45 ; General

Supply Committee, 610; Isthmian Canal Commission, 3,144; Government Printing Office, 1,685; other independent Government establishments, 6,491 ; State, municipal and other institutions and committees,

318 ; and private parties, 419.

During the past year there were distributed 1,633 iron and steel

samples, 48 brass samples, 155 ore samples, and 90 sodium oxalate

samples, as against 1,300 iron and steel samples, 57 brass samples,

183 ore samples, and 89 sodium oxalate samples distributed during

the previous year. No samples for colorimetric and polarimetric

standardization are included in these statistics. Since the chemistry

division has now taken over the responsibility for the prompt shipping of these latter samples and is also mainly responsible for their

preparation, it is intended to include them in subsequent reports

from this division.

Miscellaneous Chemical Tests.

In addition to the routine testing mentioned above, certain miscellaneous tests were made for the Government and others, which were

sufficiently thorough in character to make them partake of the nature of investigations. Among the subjects treated in this connection were metal polishes; the removal of stains from painted and

varnished surfaces and marble ; preparation of ink for marking metal

time cards; preparation of specifications for imitation Damar varnish; methods of applying enamel to small articles, such as shoe

buckles; kapok, its value in life preservers; rendering the paper of

drawings and prints sufficiently transparent to enable blue prints

to be made directly; a substitute for galvanizing; prevention of the

rusting of iron ; and the action of boiler compounds.

Publications.

The following papers and circulars have been published during

the year or are nearly ready for publication, namely, " Hewettite,

Metahewettite, and Pascoite, Hydrous Calcium Vanadates" (in

cooperation with the geophysical laboratory of the Carnegie Institu-
EEPOET OF DIRECTOR OF BUREAU OF STANDARDS. 95

tion of Washington, and published in the Proceedings of the American Philosophical Society) ; Scientific Paper No. 232, " Equilibrium

in the System Lead Acetate" (in cooperation with the optical division) ; Technologic Paper No. 41, "Lead Acetate Test for Hydrogen

Sulphide in Gas " ; Circular No. 48, " Standard Methods of Gas Testing"; Distillation of Liquid Air in a Magnetic Field" (published in

the Journal of the American Chemical Society, vol. 37, p. 1715);

third revised edition of Circular No. 32, " State and Municipal Regulations for the Quality, Distribution, and Testing of Illuminating

Gas"; "Technical AVork of the Bureau of Standards in the Gas

Field" (published in the Gas Record, vol. 1, p. 291) ; Circular No. 53,

"The Composition, Properties, and Testing of Printing Inks";

Technologic Paper No. 45, "A Study of Some Recent Methods for

the Determination of Total Sulphur in Rubber " ; third edition, en- larged, of Circular No. 38, "The Testing of Mechanical Rubber

Goods " ; " The Determination of Oil and Rosin in Varnish " (nearly

ready for publication) ; Circular No. 52, "Regulation of Electrotyping Solutions " ; " Gas-Washing Apparatus with Enclosed Filter " (published in the Journal of Industrial and Engineering Chemistry,

vol. 7, p. 534) ; "Apparatus for the Determination of Sulphur in

Gas " (published in the Journal of Industrial and Engineering Chemistry, vol. 7, p. 620) ; "A Qualitative Test for Water by the Use of

Acetylene-Cuprous Chloride Reaction" (Journal of the American

Chemical Society, vol. 36, p. 2462); "The Colorimetric Determination of Acetylene" (nearly ready for publication) ; "A simple StoneFrame Chemical Hood " (published in the Journal of Industrial and

Engineering Chemistry, vol. 7, p. 1726) ; "The Preparation of Pure

Iron and Iron-Carbon Alloys" (nearly ready for publication) ; "A

Test of a Surface Combustion Furnace" (nearly ready for publication) ; " Determination of Carbon in Steels and Irons by Direct Combustion in Oxygen at High Temperatures" (published in the Journal

of the Washington Academy of Science, vol. 4, pp. 393, 1914).

Transfer of the Work of the Contracts Laboratory of the Bureau

of Chemistry to the Bureau of Standards.

On July 1, 1914, in accordance with congressional provision, the

work of the contracts laboratory of the Bureau of Chemistry was

assumed by the chemical division of this Bureau. Owing to the

similarity of this work with that of the existing structural materials laboratory, it was deemed advisable to operate the two forces

as a single unit until a plan for reorganization could be effected.

This reorganization has been accomplished and the work is now proceeding in a satisfactory manner.

The New Chemistry Building.

Throughout the year a building committee consisting of members of the chemical staff of the Bureau, with the aid of the superintendent of the Bureau buildings and grounds, the architects, and the

ventilating engineer, have been engaged in preparing plans for the

new chemistry building authorized by Congress. The plans for the

building have been completed and the specifications printed. It is
96 EEPOET OF DIRECTOR OF BUREAU OF STANDARDS.

expected that the construction of the laboratory will begin by

September 1.

6. ENGINEERING RESEARCH AND TESTING.

Physical Equations.

During the past year the following papers along the lines of technical thermodynamics and engineering physics have been published

" Physically Similar Systems. Illustrations of the Use of Dimensional Equations," published in October, 1914, in which is considered

an important theorem regarding the forms of complete physical

equations, which is the most convenient statement, for practical use, of the principle dimensional homogeneity.

" Formulee for the Windage of Flywheels," published on January

15, 1915.

"Model Experiments and the Forms of Empirical Equations,"

presented to the June meeting of the American Society of Mechanical Engineers.

These papers will all form parts of a more comprehensive paper

to be published by the Bureau later.

A short paper has also been prepared on the dimensional theory of

wind-tunnel experiments to accompany a series of experimental

papers published by the Smithsonian Institution.

Aerodynamics.

Numerous requests for information or for experimental work on

aerodynamics have been received; for example, on subway ventilation, testing of roof ventilators, the design of windmills and aero

propellers, and the characteristics of aeroplane speedometers. Information has been supplied on some of these points and experimental tests have been made on air meters, anemometers, and electric

fans. The most important of such requests and inquiries have come

from the National Advisory Committee for Aeronautics. A report

on existing t5'^pes of aeroplane speedometers has been furnished to

them and will be published later by the Bureau, and work is now

in progress on the desigTi of a new speedometer for use by the Army

and Navy.

In the further development of aeronautics and aviation, many

physical investigations must be carried on in cooperation with constructors and operators and in response to requests for physical information and numerical data suggested by their practical experience. It is important that the Government be able to have this

purely scientific work done in its own physical laboratory, the

Bureau of Standards.

AAHiile some of this work can be taken care of under the present

conditions at the Bureau, to respond satisfactorily to the demands

which are being made the Bureau must have an adequate equipment

for experimental research in aerodynamics, and such an addition to

its staff as Avill permit of important new investigations being undertaken as requested and without unreasonable delay. It is therefore

proposed to establish a section of aerodynamics to take charge of this

work.
BEPORT OF DIRECTOR OF BUREAU OF STANDARDS. 97

Vacuum Cleaners.

Portable vacuum cleaners for use in public buildings are purchased by the Treasury Department under specifications which are based upon the results of an investigation recently conducted at this

Bureau. As a result of the Bureau's work in this field manufacturers have introduced certain changes in the design of their machines which increase both their efficiency and capacity as shown by

tests under operating conditions.

Radiator Traps Used in Connection with Vacuum Systems of

Heating.

Information of decided practical value has been obtained in the

investigation of radiator ti-aps used in vacuum systems of heating.

This work was undertaken at the request of the Supervising Architect of the Treasury. The special apparatus that was installed for

conducting this investigation has given excellent results, and the

study of the performance under operating conditions of 26 different

makes of traps is nearing completion. The data obtained will be

used in the preparation of specifications for radiator traps to be

used in connection with the heating systems of Government buildings.

Anemometers as Speed Indicators for Aeroplanes.

At the request of the Langley Aerodynamical Laboratory, a report

has been prepared on anemometers for use as speed indicators for

aeroplanes. This report, which is based upon an exhaustive study

of the various types of anemometers, including i^itot tubes, will

appear as a Bureau publication in the near future.

Water Current Meter Rating Station.

The testing of current meters, which Avas formerly conducted at

Chevy Chase Lake, is now carried out in a reinforced concrete tank

recently completed at the Bureau. This testing tank, which is 400

feet long, 6 feet wide, and 6 feet deep, offers excellent facilities for

rating meters, particularly meters of special and delicate design such

as are used by the Government bureaus to measure the velocity of ocean currents. The autographic recording mechanism designed at

the Bureau and constructed in its instrument shops, and the electrically driven carriage with hydraulic gear for accurate speed control, constitute the most complete equipment for meter rating in this

country. Although the new testing station has been in operation

only a few months, meters for test have already been received from

various parts of the United States and from Canada. The greater

part of the Bureau's work in this field at present is for the Geological Survey and the Reclamation Service, but it is certain that

the exceptional facilities offered by the new station will greatly in- crease the number of meters sent in by State governments and

engineers.

Gasoline Engines.

The Bureau's laboratory for testing the power and fuel consumption of gasoline engines such as are used in automobiles, motor boats,

and aeroplanes has been in operation for about two years. The electric absorption dynamometer used for this woi'k was installed by

10739°—15 7
98 EEPOET OF DIEECTOB OF BUREAU OF STANDARDS.

the Signal Corps of the War Department, and has been operated

under the Bureau's direction. A number of gasoline engines have

been tested, but the large demands made upon the limited engineering force have rendered it impossible to undertake any experimental

work in this field.

Tests of Miscellaneous Instruments and Devices.

The greater part of the Bureau's work in this field consists in the

rating of current meters, of which 285 were tested during the past

year. In addition, 131 tests of miscellaneous devices were made, including steam, vacuum, and hydraulic gauges, fire extinguishers,

vacuum cleaners, anemometers, tachometers, water meters, valves, and

life preservers.

7. METALLUKGY.

Fusible Tin Boiler Plugs.

An investigation has been completed and prepared for publication

on the failure and deterioration of fusible tin boiler plugs. This

safety device for preventing boiler explosions is widely used in stationary and locomotive boilers and is required on the marine boilers

on all steamboats coming under the jurisdiction of the SteamboatInspection Service, which Service brought the matter to the Bureau's

attention through the failure of a plug to operate on the steamer

Jefferson, causing loss of life. Some 1,200 plugs, both used and new,

were examined, and this investigation has shown that, although pure

tin is called for in the specifications, it often is not furnished by the

manufacturer. It appears that only 0.3 per cent zinc as impurity

is sufficient to eventually cause the complete oxidation of the tin

filling, thus rendering the plug dangerous, whereas strictly pure tin

plugs will remain sound. Several of the specifications now in force are shown to be inadequate. It would probably we well to license a limited number of manufacturers of fusible boiler plugs whose product could be controlled by Federal inspection, and not permit promiscuous manufacture. At present the Steamboat-Inspection Service

submits to this Bureau sample plugs from new manufacturers.

Properties and Standard Test Specimens of Bronzes.

The results of the investigation, undertaken at the suggestion of

the American Institute of Metals, on the variations in foundry practice as influencing the properties of standard test specimens of the

zinc bronze, known as Government bronze of composition 88 copper,

10 tin, 2 zinc, are embodied in a forthcoming technologic paper.

The Bureau also has assisted in the preparation of the specifications

for this bronze in cooperation with the American Society for Testing

Materials. An extension of this work is outlined, consisting in the

intercomparison of the properties of such specimens prepared from

the same ingot metal, but by different foundries, according to a definite and uniform plan of procedure. This will afford information

as to variations which may be expected in meeting specifications.

A metallographic examination has also been made, and the results are ready for publication, of the samples of zinc bronze (88 Cu,

10 Sn, 2 Zn) prepared at the Bureau by various methods. It would

appear from this investigation that the presence and distribution
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 99

of oxides in the casting is the predominating factor determining its

quality.

This bronze has also been studied to determine its microstructural

changes accompanying annealing. The results, which will be published shortly, show that the bronzes are very different in their

behavior from steel and show no recrystallization or " grain refining "

unless they have been previously cold worked, as by rolling or hammering.

Radiation from Metals and Oxides.

The radiation intensities characteristic of the several metals and

oxides, or their monochromatic and total emissivities, are of considerable metallurgical and pyrometric importance. The work described

in last year's report on " The Emissivity of Nickel Oxide " has since

been issued as Scientific Paper No. 224.

The same methods have been applied to iron oxide and published

in Scientific Paper No. 249. Iron oxide in the spectral region

X=0.65 ]x is almost " black," having an emissivity varying from 0.98

to 0.92 in the range 800° to 1,200° C. The total emissivity increases

from 0.85 at 500° C. to 0.89 at 1,200° C. The corrections to be applied

to optical and total radiation pyrometers when sighted on iron oxide

are as follows

:

500 °C. 600 °C. 700 °C. 800 °C. 900 °C. 1,000

°C. 1,100 "0.

1,200 °C.

Radiation pyrometer +30 +30 +35 + 1 +35 + 2 +40 + 4 +40 + 6 +45

+10

The micropyrometer (see Scientific Paper No. 198) has also been

adapted to the measurement of the monochromatic radiation of metals and oxides, it being possible to take observations rapidly and

over a large temperature range on a quantity as small as 0.01 mg.

presenting a surface of 0.25 mm-. The results of observations on 23

metals and 12 oxides have been published in Scientific Paper No.

242, showing that, in general, there is no temperature coefficient of

emissivity and that for several metals, including platinum, there is a discontinuity in radiation at the melting point. This would render

the Violle unit of light, based on platinvim brightness at its melting

point, a variable standard.

The Quality of Platinum Ware.

The thermoelectric method of classifying platinum ware, described in the last year's report, has been supplemented by measure- ments on the loss of weight of platinum on heating, with the object of

determining the specifications and best composition for platinum

ware, such as crucibles, Avhich ai^ subject to loss of weight on heating; a phenomenon which is very troublesome to the analytical

chemist and which reduces the accuracy of his results. This investigation, which was undertaken at the suggestion of the American

Chemical Society, afforded incidentally an opportunity, through the

many samples examined, to form an estimate of the purity of high-
100 EEPOET OP DIRECTOE OF BUREAU OF STANDAEDS.

grade platinum ware on the American market. Thus, of 164 samples examined, including a wide variety of objects, 43 pieces contained an equivalent iridium content of less than 0.5 per cent and 110 less

than 2 per cent iridium. The loss of weight on heating for iron-free

crucibles ranged from 0.71 mg. to 2.96 mg. per 100 cm^ and per hour

at 1,200°, the greater losses being for crucibles containing iridium

and the lesser with those containing rhodium. From the thermoelectric measurements of purity, combined with a microscopic examination, the probable loss of weight for any platinum crucible can be

predicted with sufficient accuracy for analytical purposes. It is suggested, for highest grade crucibles, that iron-free platinum containing 3 to 5 per cent rhodium be specified. This thermoelectric examination of platinum purity is now a regular Bureau test; also the

Bureau's advice has been sought by several departments of the Government and other large users of platinum concerning purchases

under this test. Causes of Failures of Railway Materials.

In conjunction with the engineering and chemical divisions a comprehensive series of investigations of the causes of failure of railway

materials has been undertaken, including some of the fundamental

problems in the manufacture, design, and properties of rails, wheels,

tires, and axles, as related to their failure in service.

During the past year considerable necessary equipment has been

assembled and a start made on several problems, including soundingot research, rail-finishing temperatures, transverse fissures in

rails, properties of cast iron, thermal analysis, and metallographic

methods of examination.

A very important event in this connection was a meeting held at

the Bureau May 22, 1915, attended by the technical representatives

of 24 railway systems, at which the work of the Bureau on railway

materials was discussed and a plan of cordial cooperation inaugurated, including the furnishing by the railways of statistics of fail- ures and material for examination. It is believed that by thus working in cooperation with the railroads and gaining the benefits of their

varied and extensive experience and technical advice, more rapid

and efficient progress in the solution of the problems of the causes of

failure of railway material will be made. The advantages of a centralized experimental laboratory which also has access to the material in service are manifest.

Causes of Failure in Car Wheels.

A study of car wheels is projected in view of the fact that they

constitute one of the principal causes of railway accidents, and there are many matters of uncertainty as to best practice in manufacture

and design. There are, for example, over 20,000,000 " chilled castiron " wheels in vise in the United States and thej^ are interchangeable

from one railway to another, so that specifications should be rigid

and uniform. Some of the items to be studied are statistics, foundry

practice, mixtures used in manufacture, effect of sidphur on properties, braking and internal strains, strength of and best design, properties of hot cast iron, soaking pit practice, and relation of combined

carbon to annealing. A beginning has been made on the last item.
EEPOKT OF DIEECTOR OF BUREAU OF STANDARDS. 101

Transverse Fissures in Rails.

The problem which the railway conference of May 22, 1915, con- sidered the most urgent is the determination of the causes of " trans- verse fissures," a hidden defect or split in the rail which often makes

its occurrence evident only by the rupture of the rail by a train. A

series of questions on this subject have been submitted to practically

all the railroads in the United States, asking for their experience,

data and samples, and for suggestions as to methods of attack. The

replies which are being received will be a most valuable guide in

orienting this investigation, which will involve work in the laboratory, mill, and service, including trials of artificial producton of such

fissures by several methods, metallographic and chemical surveys of

rails containing fissures compared with sound rails, examination of

rails which have withstood long, severe service, and the effects of

mill practice, including internal strains, gagging, and the completion

of the chemical reactions across the rail section as influenced by

manufacture. It is also hoped to have the cooperation of the optics

division in the determination of the variation of expansion coefficient across the rail section. '

Finishing Temperatures of Rails.

The survey of American practice regarding the finishing temperatures and properties of rails, mentioned in last year's report, was presented before the American Institute of Mining Engineers and has

been j)ublished as Technologic Paper No. 38. The subject of finishing temperatures is one of the greatest importance in rail manufacture, and the discussion of the subject was participated in by several

of the most prominent authorities in the country ; and this discussion

brought out a general confession of ignorance of many matters con- nected with the relation of methods of manufacture to the resulting

properties of rails. It is hoped to be able to aid in the solution of

some of these outstanding uncertainties. In Technologic Paper No.

38, the " shrinkage clause " in rail specifications such as those of the

American Society for Testing Materials (defining the finishing tem-

]3eratures by the shrinkage of the rail) was shown not to fulfill the

intended requirements of its framers in limiting the temperature to

slightly above the recalescence point. The rail committee of the

American Society for Testing Materials presented a report concluding " there is lacking anything which points to such decided differ- ences in the quality of rails rolled at varying temperatures as theoretical considerations have led some of us to expect." The society has

instructed its rail committee to cooperate with the Bureau in a further investigation of this important matter.

It is also proposed to study several allied questions, including the

relation of rail section to the temperature distribution on cooling,

and the relation of the latter to the completeness of the chemical

reactions, internal stresses, and metallographic transformation for

different sections and compositions of rails.

Sound Ingot Research.

The use of only sound steel ingots for the manufacture of rails

and other structures, on which the safety of the public depends, is a matter of the greatest importance. With the cooperation of several
102 EEPOKT OF DIRECTOR OF BUREAU OF STANDARDS,

steel manufacturers, the Bureau has been enabled to compare the

behavior and properties of several types of ingot, including the Hadfield form, consisting in (1) piping steel, (2) cast large end up, (3)

suitable sink head with (4) air blast on charcoal and slag. This

method produces an ingot, 90 per cent of which is physically and

chemically sound. The results of this investigation, including also

an examination of rails rolled from some of these ingots, were presented before the American Institute of Mining Engineers and also

before the British Iron and Steel Institute. Opportunity has also

been offered for a further study of this tyi^e of ingot by the Pennsylvania Railroad, which is to have rolled into rails 100 tons of Hadfield ingots, to be studied in detail by the Bureau.

Arrangements are also being made to study other processes of

manufacture of sound ingots, such as the compression process of

Mr. B. Talbot, of Middlesbrough, England, and the " hot-top " ingots

of the Cambria Steel Co., together with an examination of the effects

of such ingredients as vanadium and titanium.

It is believed that an impartial study by the Bureau of the methods

of manufacture of steel ingots, blooms, rails, and similar prodiicts

will be helpful in stimulating an improvement in manufacturing

methods and should result in more rigid specifications being enforced

for those products the use of which involves life hazard.

Test Ingot Investigation.

A matter of very great practical importance in the buying and

selling of steel, involving acceptance or rejection of the material

under specifications, is the determination of its analysis. The usual

practice is to take for analysis a " test ingot " from the ladle before

casting and assume this to be representative of the finished j)roduct.

These test ingots vary greatly, however, in shape and size and quality, and it seemed desirable to endeavor to standardize this practice.

The study has been continued during the past year with the co- operation of the American Society for Testing Materials. Data

have been collected regarding American practice in the matter of the

shape and size of such ingots, methods of sampling, etc. Seventeen

of the leading steel companies have cooperated in the work by furnishing sample ingots of various grades of metal. This first series

examined represents ingots poured directly; thatis, without the addition of aluminium, silicon, or other substances for rendering the

metal compact and free from blowholes. Later the influence of such

additions Avill be considered.

Fifty-five ingots have been examined up to date. This examination, so far, has been entirely metallographic, including the mapping

out of the regions of segregation of sulphur (as an index of the

segregation in general) and the determination of the presence of

included " scale," oxides, etc., in the porous metal. Careful chemical

surveys of selected types will supplement and confirm this work.

Up to the present the investigation seems to warrant the conclusion

that shape and size of the ladle ingots are minor factors and that

the investigation of the subject of additions to the metal upon pouring to render the ingot sound and free from holes is the most satisfactory solution of the problem.

This work should be extended eventually by a comparison of " test ingot" analysis with that of the finished products. It would ap-
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 103

pear that, at least for certain classes of materials, such as rails, the

"test ingot" method of analysis should be rejected in favor of the

analysis of the finished product.

Foreign Railway Specifications,

A technological paper has been prepared on foreign railway

specifications for rails, wheels, axles, and tires. This material was

collected with the aid of the Department of State from the Governments or railway administrations of Austria-Hungary, Belgium,

France, Germany, Great Britain, Holland, Italy, Russia, and Sweden.

The circular contains a comparison and discussion of these specifications, including a summary of accident statistics, as well as translations of the foreign text of the specifications for rails, wheels,

axles, and tires. It is expected the circular will be of interest to

those responsible for and interested in the specifications for such

railway material in the United States. In general, it may be stated

that the foreign railway material, such as rails, wheels, tires, and

axles, appear to perform the duty imposed upon them in a more adequate manner than is the case in America.

Failure of Structural Brasses.

A comprehensive study of the causes of failure in service of structural brasses and bronzes has been undertaken by the Bureau. The

costly experience of the New York Board of Water Supply on its

Catskill Aqueduct project as well as the failures of bronze in the

Minneapolis filter plant and elsewhere, the former of which has

been widely advertised, raised the questions whether the bronzes

used for such structural purposes were suitable for the purposes for

which they were designed, whether the specifications were inadequate, or the methods of manufacture at fault. There appears to be

a very serious lack of reliable data upon which to draw up specifications for this type of material and the ordinary tests do not

lasually give an indication of the true permanency of such bronzes

which may easily be spoiled in manufacture.

The Bureau has had the cooperation of a number of brass and

bronze manufacturers who have furnished material made, as suggested by the Bureau, in several ways; and the Bureau has been

able to obtain failed material from several sources, including the

New York water board, city of Minneapolis, and the Navy Department.

The relation of the presence of internal stresses to methods of

manufacture and subsequent heat treatment have been carried out

for numerous samples from various sources. It would appear that

the presence of these internal stresses, sometimes associated with

corrosion, is largely responsible for failure. It has also been shown

these stresses can be removed by annealing, without serious detriment to the physical properties. The effects of corrosion on stressed

brasses is also to be studied. There is in this problem of defining the

just limitations of nonferrous alloys for structural and other purposes a wide field of research.

A preliminary account of the work already done is being prepared for publication.
104 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Preparation of Pure Iron and Iron Carbon Alloys.

It is shown that previous work on the iron-carbon diagram is unsatisfactory because of the great variation in the materials used. It

was, therefore, thought necessary to produce a series of alloys of great

purity to form the basis of a redetermination of the diagram at the

Bureau of Standards. The general method consisted in melting

electrolytic iron with sugar carbon in magnesia crucibles. The electrolytic iron was prepared from ingot iron anodes in a chloride bath

with or without the use of porous cups. The operation of melting

the iron with carbon gave great trouble at first because the ingots

obtained were full of blowholes and contained considerable quantities

of impurities. These difficulties were overcome by melting in a vac- uum furnace and making crucibles of especially pure magnesia, made

and calcined at the Bureau of Standards. A satisfactory procedure

was finally worked out and a series of alloys prepared of the composition Fe-f-C= 99.96 per cent. The Iron-Carbon Equilibrium.

During the early part of 1914 work on the thermal analysis of pure

iron was completed and the thermal study of the iron-carbon series

was started. A large number of alloys ranging from 0.02 to 1.8 per

cent carbon were made up and observations taken by the inverse rate

and derived differential methods for some 250 heating and cooling

curves. These observations have all been plotted and a study of

the effect of rate on the location of the critical points has been started.

Upon the completion of this work and a study of the effect of decarbonization, the results will be ready for publication. Work on this

problem has been delayed or interrupted by the preparation and

installation of exhibits for the San Francisco exposition and by

testing.

Determination and Distribution of Carbon in Steels and Irons.

The improvement of analytical methods in metallurgical chemistry

are of great economic significance as well as of scientific interest.

Two methods for the rapid determination of carbon in steels have

been devised, one by direct combustion in oxygen at high temperatures, a preliminary account of which has been published ; the other

by a conductivity titration method, which is in preparation.

The relation of the amount of graphite to the heat treatment of

cast iron is of importance in the maniifacture of chilled cast-iron

wheels. Some preliminary work has been done in cooperation with

one of the wheel manufacturers.

The Physical Properties of Pure Iron and Copper,

The pure iron made at the Bureau is being studied for several of

its physical properties. Scientific Paper No. 236 has been published

describing the experiments on the electrical resistance and temperature coefficient of pure iron between 0° and 950° C. These experiments, carried out with a precision of 1 in 300,000, demonstrate the

nonexistence of transformations below 757° C, show the Acg and Ar^

transformations to begin at the same temperature 894° C. and extend

over 25°, and accompanied by a decrease in resistance on heating and

an increase on cooling through the A3 transformation. The Aj trans-
EEPOET OF DIRECTOR OP BUREAU OF STANDARDS. 105

formation, the interpretation of which is still in dispute, is evidenced

by a very sharp cusp at 757° C. in the temperature coefficient curve, or by an inflexion in the resistance curve. Exact measurements have been taken of the resistance of copper in

the interval 0° to 100° C. with the object of detecting allotropic

changes which have been reported by Prof. E. Cohen, of Utrecht.

Melting Points of Steels and Refractory Elements.

The determination of the melting points of a considerable number

of steels of practical importance has been undertaken and is nearly

complete. Also the melting points have been determined, by means

of the micropyrometer, of practically all of the refractory chemical

elements. It is hoped to be able to publish these results shortly.

A Test of a Surface Combustion Furnace.

In view of the fact that the surface combustion process appeared to

offer many advantages for high-temperature laboratory furnaces, in

which the Bureau is interested, it was decided to submit a crucible

furnace of this type to a thorough test. For the purpose, the furnace

was equipped with meters on the gas and air lines, and with a chimney to permit the collection of flue-gas samples. In several runs the

mixture proportions were maintained constant while varying the rate

of gas consumption. Temperatures were read by a Holburn-Kurlbaum optical pyrometer. The highest temperature reached was

1,675°, at which point the muffle failed. The test established that

complete combustion could be attained without excess air, that the

best air-gas ratio was 5-6, and that a 20 per cent excess of air caused a lowering of furnace temperature of 100°. An account of this test,

which is the first of its kind, is in course of preparation.

Nomenclature of Nonferrous Alloys.

A paper which evoked considerable discussion was presented before

the American Institute of Metals on the " Progress in the Nomenclature of Alloys." There is great need for systematizing the naming

of complex alloys and of their constituents. The coining of new

names and the use of proper names is being discouraged, and it is

probable that from the several suggestions which have been made a

rational system of nomenclature may be worked out which meets the

needs of the foundryman on the one hand and is correct scientifically

on the other hand. The Bureau of Standards in cooperation with the

American Institute of Metals is considering the matter, and it has

been hoped to bring about uniformity for the English-speaking coimtries through the cooperation of the British Institute of Metals and

its allied ' societies ; and possibly, at least as concerns some of the

fundamental principles, international agreement may be reached

through the active advocacy of the subject by the editor of the International Journal for Metallography.

Investigation of Molding Sands.

In cooperation with the American Institute of Metals, the Bureau

has begun an investigation of the properties and methods of testing

molding sands, with the object of finding out the characteristic qualities of such sands as have proved serviceable and endeavoring to put
106 EEPOET OP DIKECTOE OF BUEEAU OF STANDAEDS.

on a better scientific basis the classification of molding sands. A preliminary report will be presented at the fall meeting of the American

Institute of Metals.

Pyrometric Standard Samples.

In response to numerous requests, arrangements are being made for

the preparation, testing, and certification of certain pure metals of

known and exactly determined melting points, such as tin, zinc,

aluminium, silver, and copper, as pyrometric standards for distribution for the calibration of pyrometers. Several firms have offered to

assist in furnishing such samples. The metallurgical and heat divisions will cooperate in this work.

Specifications for Metals.

The Bureau has received many verbal and written requests for

copies of its specifications for various metals and alloys, and surprise

is often expressed that the Bureau has no specifications of its own for

these materials. There are many lines of specification work in metals

which it would be highly desirable for the Bureau to take the lead in

framing specifications which would serve as models for other branches

of the Government service and elsewhere. This would require a considerable increase in the staff. Some of this work is, of course, now

done in connection with committees of the several technical societies,

but the work could well be sj^stematized. As at present conducted, it

is somewhat haphazard and accidental and often is not backed by

sufficient experimental evidence such as the Bureau could furnish.

Cooperation with Manufacturers on Nonferrous Metals.

A very important feature of the work in metals at the Bureau has

been the cooperation with manufacturers on nonferrous metals, including representatives of the American Institute of Metals, the

American Chemical Society, the American Institute of Mining Engineers, the American Society for Testing Materials, and the American Electrochemical Society. Two well-attended meetings have been

held during the past year at the Bureau, which has greatly aided in

suggesting and mapping out lines of work, securing typical materials

or samples, and obtaining the aid and benefit of the experience of

many manufacturers for several problems in which the Bureau is

interested. Very cordial and reciprocal relations have thus been

established, which are of mutual benefit.

Metallurgy and Chemistry of Platinum-Group Metals.

Provision should be made for the study of the metallurgy and

chemistry of the metals of the platinum group. This would require

the installation of special furnaces and refining apparatus in addition to the chemical equipment, and the services of two or three men,

one of whom should be skilled in platinum refining.

Systematic Investigation of the Properties of Metals.

Knowledge of the properties of even the more commonly used

metals and alloys, especially at high temperatures, is very meager,

and their determination requires, in many cases, elaborate and costly

experimental arrangements and considerable skill.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 107

The Bureau is in receipt of many insistent and reiterated demands

for many of these constants which can not be obtained elsewhere and

which are needed in many lines of practical work. There is no way

in which the metallurgical division of the Bureau could better serve the community than by inaugurating a systematic series of experiments on the determination of the physical constants of metals.

This work should be divided into two correlated classes—(1) the

gathering and digesting of existing data, much of which exists only

in private records, especially of some of the larger manufacturing

companies (the Bureau should become a clearing house for the as- sembling and publishing of data thus made available) ; (2) actual

experimental investigations by the Bureau.

That the country needs and expects the Bureau to take up this

work on a more extensive and comprehensive scale than has been

hitherto possible is evidenced by the fact that representatives of five

of the principal scientific and technical societies have pointed out the

necessity for such w^ork, as have engineers separately. A resolution

was passed by the iron and steel committee of the American Institute

of Mining Engineers "that the Bureau of Standards be requested

by this iron and steel committee to give attention to determining

some of the lacking chemical and physical data concerning iron, more

particularly the latent heat of fusion, specific heat in the liquid state,

and heat conductivity up to the melting point, of pure iron and typical steel and cast iron."

It is also felt that such determination of physical constants when

made by the Bureau will be unbiased, exact, and carry the weight of

the authority of an impartial body of experts. This is an important

phase of the matter, particularly when dealing with products that

come into competition with each other.

Several manufacturers have expressed the willingness and urgent

desire to furnish in quantity the pure materials required, such as

zinc, aluminium, and copper, which would be especially purified for

the purpose. A special fund should be provided for this purpose.

Aid Rendered the Public by Metallurgical Investigations.

Most of the investigations being made of metals have been undertaken at the request of technical societies, departments of the Government, railroads, manufacturing firms, or individuals; and in all cases the problems being studied are of general interest and represent endeavors to find answers to specific questions of considerable

importance to large classes of people.

As examples may be mentioned the study of structural bronze and

brass failures, which is of far-reaching importance in defining the

proper use of and specifications for these materials, first imdertaken

at the instance of the board of water supply of the city of New York

and the city of Minneapolis, and later with the cooperation of many

manufacturers; the investigation of causes of failure of fusible tin

boiler plugs, requested on behalf of the Steamboat-Inspection Service,

but of interest to ali users of boilers employing this safety device;

and the determination of the quality of platinum ware, started at the

request of the American Chemical Society, and of interest to all users of such material.
108 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

Metallurgical Testing.

The following tests were completed during the year

Name.

Heat treat- ment, thermal

analysis. Metallographic.

Fusible plugs.

s>nd.

lauutgs.

MisceUar

neous.

Grand

total. Nonferrous metal.

Irons and

steels.

RailfaUures.

Identifica- tion method

and

process

of manufacture.

Metal

faUures.

Miscolla- neous.

For the Government: Panama Canal 2

45

3

104

246 Bureau of standards

Misoellaaeous 5 2 9 1,0U3 2

Total 5 50 2 134 9 1,063 2 1,2G5

38 7 13 173 1 232

Grand total 5 88 2 141 9 13 1,063 173 3 1,497

Of these 1,497 test items, 1,265, or 85 per cent, were for Government

departments. The Government tests were distributed among the

Isthmian Canal Commission (106), Bureau of Standards (69),

Steamboat-Inspection Service (1,062), Bureau of Lighthouses (5),

War Department, Quartermaster General's Office (6), Interstate

Commerce Commission (3), Naval Inspector of Ordnance, .Philadelphia (3), and 1 or 2 each for the chief clerk's office, Department of

Commerce; Naval Supply Depot, Brooklyn; Naval Gun Factory,

Washington; Bureau of Mines; Superintendent, Capitol and

Grounds ; National Zoological Park ; corporation counsel. District of

Columbia; Post Office Department; and Supervising Architect's

Office, of the Treasury.

Several of these tests, particularly of failed materials, necessitated

elaborate researches, and will serve as the basis for publications con- cerning the various types of metal failures.

Information Furnished as to the Properties of Metals.

The metallurgical division of the Bureau has furnished by corre- spondence much information concerning the properties of metals,

and has received many visits from representatives of firms desiring

similar data. For example, in one month representatives of the

following interests visited the Bureau to ask its advice: A watch

company, concerning nonmagnetic and nonexpansible alloys; a steel

company, on the improvement of rails with titanium; a brass company, as to metallographic methods; a car-wheel company, concern- ing railway materials and metallographic standards; a car-wheel

company, in regard to chilled wheel design and service ; a steel company, as to temperature control in the manufacture of ordnance; a brass company, concerning properties of nonferrous alloys, etc. Others have visited the Bureau to become acquainted with its methods
KEPOET OF DIEECTOE OF BUEEAU OF STANDAEDS. 109

of testing and research, among them representatives of railroads,

steel works, universities, instrument manufacturers, etc. Typical questions handled by correspondence have been the improvement of malleable iron, from a manufacturer; aluminium dis- ease, from a farmer; paint for metals to stand 800° F., from an

enameling firm; case hardening and composition for rock drills,

from a mining company; bronze bearings for heavy grinding machines; alloy that can not be remelted at original melting temperature; fusible boiler plugs data, from manufacturers; strength of

vanadium steel, from an engineer; cooling curves of ordnance steel,

from an ordnance officer; suitable steel for guy rods: soldering of

iron sheets; failure of locomotive boilers by cracking at seams; case hardening of machine steel ; alumina in steel, from a steel company

;

properties of forged Trrought iron ; equi^'alence of Ni and Cr to car- bon in hardening rails, from a railroad ; numerous inquiries concern- ing foundry practice, both fi'om iron and brass foundries; abrasion

of metals; exjoansion of metals with tune and temperature, from a railroad company : methods of manufacture of various alloys ; melting points and heat treatments of steel : suitable metals for printingplates; cutting metals with metallic disks; suitable resistance wires;

substitutes for zinc for various uses; metallic thermostats, from

an instrument manufacturer; bearing metals for watches and for

locomotive parts; properties of molybdenum, from a handbook compiler; composition of a white nontarnishing alloy, from a manufacturer, etc.

Metallurgical Publications.

The following publications have been issued during the year : Technologic Paper Xo. 38, on " Observations on Finishing Temperatures

and Properties of Rails ; " Scientific Paper Xo. 2'2-J:, " Xickel Oxide ; "

Scientific Paper No. 212, " Measurements with the Micropyrometer ; "

Scientific Paper No. 249, " Iron Oxide ; *' Scientific Paper No. 236,

" Electrical Resistance and Critical Ranges of Pure Iron ; " " Progress in the Nomenclature of Alloys," published in the Transactions

of the American Institute of Metals, Vol. VIII. p. 46, 1914; "Determination of Carbon in Steels and Irons by Direct Combustion in

Oxygen at High Temperatures,'" published in the Journal of Washington Academy of Sciences, vol. 4, p. 393, 1914; ''Sound Steel

Ingots and Rails," published in the Proceedings of the American

Institute of Mining Engineers and the Proceedings of the Iron and

Steel Institute of Great Britain. Other papers in course of preparation and in press are " Characteristics of Radiation Pyrometers ;

"A Study of the Quality of Platinum Ware ; " "An Investigation of

Fusible Tin Boiler Plugs ; "

" Standard Test Bars of Zinc-Bi*onze

:

88 Copper, 10 Tin, 2 Zinc:" "Some Foreign Railway Specifications: T\^ieels. Rails, Axles. Tires;" "The Microstructural Changes

Accompanying the Annealing of Bronze : 88 Copper. 10 Tin. 2 Zinc ; "

" Failure of Structural Brass; " " Preparation of Pure Iron and Iron

Carbon Alloys ; " "A Test of a Surface Combustion Furnace ; " and

" Methods of Testing Molding Sand."
110 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

8. STRUCTURAL, ENGINEERING, AND MISCELLANEOUS MATERIALS.

Structural Steel Column Tests.

An important investigation now in progress which is of vakie to

the engineering and architectural professions consists of a series of

cohimn tests which the Bureau is making in cooperation with the

steel-column committee of the American Society of Civil Engineers

and the steel-column committee of the American Eailway Engineering Association.

The series of the American Society of Civil Engineers comprises

9 different types of cross section. With one exception, 18 columns

of each type have been fabricated for testing, 9 of light and 9 of

heavier structural shapes. The 9 columns, both of the light and

heavy kind, are made in 3 different lengths, so that there are 3 columns of each type and weight of section having the same length.

During the progress of this investigation it was decided to extend

this series of columns by 24 additional columns now being fabricated.

These columns will be of the same types as those already furnished,

but some will have different lengths and others will be made of

heavier structural shapes.

The American Eailway Engineering Society's columns comprise

18 latticed columns with rectangular bearing plates at both ends.

Only one type of ci'oss section but of two different weights of structural shapes has been tested. Both light and heavy columns are made

in 3 different lengths, there being 3 columns of each length and

weight of cross section. Thirty-six additional columns of this type,

but modified in some single detail, are now being fabricated for the

purpose of determining the effect of such modifications on the

strength of the columns.

In addition to these column investigations, a large number of steel

bridge columns have been tested in cooperation with prominent

engineers. The columns are facsimiles of members from long-span

bridges which are being erected or soon will be erected in America.

The reports on the data and results of these tests, when completed,

will be very valuable to bridge designers, as such data on large size

columns have not been available before.

The purpose of these tests is to determine the best forms of cross- section of columns and also to correct or confirm the formulas used

by engineers and architects for calculating the strength of columns.

Not alone are such formulas valuable for determining the loads

which can safely be carried by the columns used in various structures, but they also enable the designer of columns to make the most

economical use of the steel emplo5^ed in their construction.

Although the testing of these columns consumes much time, since

it must be done very carefully in order to secure reliable results, this

investigation has made good progress during the past year. More

than three-fourths of the two series of columns have now been tested.

The results of these tests show that with one exception the columns

made of the heavier structural shapes fail at loads per square inch of

cross section which are about 10 per cent less than those which produce failure of the columns of the same type but of lighter section.

The work has not progressed far enough to admit of drawing any
REPOBT OF DIEECTOR OF BUREAU OF STANDARDS. Ill

definite conclusions from the tests, and it may be necessary to again

extend the present program of the investigation before arriving at a

final interpretation of the results.

Tests of Large Columns for Long-Span Bridges.

Through the cooperation of several consulting engineers and manufacturers Avith the Pittsburgh branch laboratory, it has been possible

during the last three years to carry to completion an investigation

upon the strength and behavior of 18 large bridge columns when

under loadings. The columns varied in size from 50 to 120 square

inches in cross section, and were constructed of various alloys and

high-carbon steels, some of the specimens being the largest ever

tested. These 18 specimens corresponded throughout with certain top

chord members selected from the following long-span bridges re- cently erected in America: The Municipal Bridge, at St. Louis; the

Chicago, Burlington & Quincy Railroad Bridge, at Metropolis, 111.

;

and the new bridge at Memphis, Tenn. In carrying out this investigation a study was made of the action of the columns as a whole to

determine the relation of maximum loads to yield points of the grades

of steel used. The elastic coefficients of the " built-up " members

were found and the causes of initial strain induced in fabrication

hj the driving of rivets were analyzed. The laws affecting the distribution of stress and strain in the lattice, pin plates, and other details were studied with reference to the efficiency of these particular

types of details used by their designers. Heretofore the inadequate

capacities of American testing machines have imposed restrictions

which prevented tests being made on large columns to the full maximum load at failure. Many of the present columns sustained from

3,000,000 to 6,000,000 pounds before collapse, and the derived data

covering the behavior during tests will be of value to bridge and

consulting engineers and manufacturers Avho are engaged in the construction of large railroad bridges. The research will also afford

practical data for a proper formulation of the real mechanics of

the column. These mechanics have in the past largely been based

on purely theoretical considerations founded upon inductions made

from the results gotten in the case of small laboratory specimens,

there being but few systematic investigations previously made upon

large columns of the type here considered.

Causes of Failure of Railway Materials.

The investigation as to the causes of failure of rails and other

railway material has been continued during the past year. Numerous

specimens of rails which failed in service have been received by the

Bureau from several railway companies Avho offered their cooperation and assistance in this work. The failure of each of the specimens

furnished was caused by the formation of transverse fissures in the

interior of the rails and the Bureau is now endeavoring to ascertain

under what conditions this type of failure is produced. Special, shop

equipment to facilitate the preparation of the specimens for the

necessary chemical, microscopic, and physical tests has been recently

installed. The results of this investigation will contribute toward

safer railroad communication.
112 BEPOET OF DIEECTOE OF BUEEAU OF STANDAEDS.

Standard Test Specimen for Cast Bronze.

The investigation made by the Bureau at the reqviest of the American Institute of Metals preliminary to the establishment of a standard test specimen for cast bronze has been completed. About 800

sj)ecimens were prepared from a typical bronze consisting of 88 per

cent of copper, 10 per cent tin, and 2 per cent zinc, and tested for

ultimate strength. The results of these tests taken in conjunction

with the results of the investigation of the metallurgical division led

to the adoption of a certain form of cast test specimen as a standard

for such materials. (See also "Metallurgical investigations.")

Influence of Time in Testing Steel Specimens.

The investigation made by the Bureau in cooperation with the

American Society for Testing Materials to detennine the effect of

the speed of application of the load on the yield point of a steel

specimen in tensile tests has not yet led to any definite conclusion,

the results obtained so far not being sufficiently concordant. The

yield point is the load in pounds per square inch at which a flow of

the metal occurs when subjected to tension or compression. The

purpose of this investigation is to ascertain the best speed of applying the load when making commercial tensile tests of A^'arious kinds

of steel.

Behavior of Spring Steel under Repeated Static and Dynamic

Stresses.

Work has been continued on the heat treatment of 1 per cent

carbon steel with special reference to the development of endurance

to repeated stresses such as are met in service. The steel is being

studied in the quenched condition as well as in its final state after

being drawn. This work has brought out some difficulties, the solution of which it is hoped will advance our theoretical knowledge

and improve the practice of heat treatment. This investigation

has been carried on jointly at the Bureau and the Altoona shops of

the Pennsylvania Eailroad on certain locomotive springs which have

been a source of considerable trouble up to the present time.

Calibration of Testing Machines.

It is desirable to test the accuracy of the reading of testing machines from time to time, especially during the course of a long

investigation. With this point in view, the Bureau has secured

apparatus for testing machines up to 50,000 pounds capacity and has

undertaken the design and construction of apparatus with which it

hopes to be able to standardize its own machines as well as those of

the public to a point which lies as far beyond the 50,000 pound limit

as may be necessary. Considerable progress has been made during

the past year in this direction, so that the Bureau will soon be ready

to standardize machines to 200,000 pounds capacity.

Information Regarding the Strength of Metals and Their Alloys.

Much assistance has been rendered by the Bureau during the past

year in the form of answers to correspondents seeking information

as to the strength and other properties of metals and on allied subjects. These inquiries were received from Federal Government de-
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 113

partments, municipal and State governments, universities and

schools, engineering societies and research laboratories, corporations,

and private individuals.

The inquiries relate to a wide range of subjects. Many were

requests for technologic papers issued by the Bureau and sources of

engineering literature printed elsewhere. Specifications for various

materials, such as pipes, steels, hard-drawn copper bars and wires,

hardware, tools, timber, materials for machine parts, and helical

springs were often requested and on several occasions the Bureau was

asked to interpret the existing standard specifications for materials

and methods of tests. The Bureau's opinion has been frequently

sought regarding the feasibility of various new devices, such as waterproof piles, devices for pneumatic riveting, and welding joints.

Inquiries have been made concerning the testing machines, methods

of testing, and kinds of testing apparatus needed for particular

purposes. Information as to the cause of failure of manufactured

materials has been the basis of many requests.

Tests on the Strength of Materials.

The test of compression and tensile strength, transverse bending

Kstrength, and hardness made at the Washington laboratories were for

practically all departments of the Government. Over 200 tests were

made on ferrous metals. These tests included, besides the usual

specimens of different steels, tests of a jack cable reel, steel and galvanized iron wires, shafting, rollers, horseshoes, rail specimens,

screw-box collars, header test bars, cast and malleable iron bars and

bolts. One hundred and eighteen tests of nonferrous metals Avere

made, such as bronzes and brasses, monel metal, bronze sash chains,

and copper wires and plates and aluminum bars; 28 tests of sundry

materials, such as porcelain insulators, vulcanized fiber, micanite,

glass rings, and timber ; compression tests of two large 10-inch glass

cubes used for the insulation of radio towers, and tensile tests of 15

hemp ropes have been ipade. Besides, more than 300 pieces of

structural steel for two Federal buildings, now being erected, were

inspected; 5 testing machines having capacities of 100,000, 200,000,

400,000, and 800,000 pounds, the last being the Emery machine at

the Watertown Arsenal, were calibrated or compared with the

Bureau's machine; 3 jackscrews were tested for lifting capacity and

3 large bridge columns for ultimate strength.

Numerous tests of a general routine nature at the Pittsburgh

branch were made for various departments of the Government and

for manufacturers or individuals, these covering 290 tests of manila

rope ranging in diameter from one-half inch to 3^ inches, 25 tests of wire cables, a number of tests of porcelain insulators for wireless

transmission towers, and numerous miscellaneous tests upon steel

and iron bars, granite blocks, as follows

:

In connection with the work of the cement division, there were

made 750 tests upon standard 6-inch concrete cylinders, 100 6-inch

cubes of concrete, and 1,350 tests of 2-inch cement cubes. There

were made numerous tests for manufacturers, these consisting of 12

tile walls, 6 feet long and 10 feet in height, both transversely and

under compression ; 4 transverse" tests on street-car rails to determine

efficiencies of various methods of electric welding, and a number of

10739°—15 8
114 REPORT OF DIRECTOR OF BUREAU OF STANDARDS,

tests of brick of various types. Four large hydraulic jacks of 40

internal diameter to be used in connection with the erection of longspan bridges were tested under proof loads to determine the action

and efficiency of the cylinder packing rings. Twelve car couplers

were tested under proof loadings, and a number of miscellaneous

tests, aggregating about 100 specimens, were made on specimens of

steel for rolls, cast-iron specimens, granite and limestone cubes,

hollow tile, flexible casing for lamp cord, etc. Standard Specifications for Portland Cement.

Meetings of the joint conference of representatives of the United

States Government, the American Society of Civil Engineers, and

the American Society for Testing Materials were held during the

year and final agreement was reached on one specification for Portland cement which was recommended to all three organizations for

adoption. If this specification or a modified form is finally agreed

upon, it will result in one recognized American standard instead of

several as at the present time, with its attending advantages to the

cement industry as well as the engineer. The recommended specification includes several modifications from previous existing specifications which it is believed will furnish a cement of improved quality.

The United States departmental conference on cement specifications,

which was organized by the Bureau of Standards, will probably take

action upon this specification during the ensuing year.

Hydraulic Cements Other than Portland Cement.

In the investigations under way dealing with Portland cement it has been necessary to determine the properties of the silica-aluminalime compounds other than present in normal Portland cement. The

result has been the finding of some very interesting lime-alumina

compounds which developed very hard dense mortars which have a Yevj high strength at early periods. The introduction of moderate

amounts of silica and iron oxides into these serves to increase still further the high strengths which are obtained in compression, and

also results in the production of ternary compounds which seem to

have hydraulic properties of considerable value. A survey of these

less known and seldom used compounds has been but preliminary,

although the results have justified further work which was carried on

at the Pittsburgh branch during the year with burnings made in the

rotary kiln.

Further Studies of the Hydration of Portland Cement,

There was published during the past year a paper on the Hydration of Portland Cement. This represented the results of an investigation, carried on largely during the previous year at the Pittsburgh

branch, dealing with the products of the hydration of the constituents of Portland cement clinker. There was no quantitative relation established between the products of hydration and the strength

produced. During this year, however, the constituents ordinarily

present in clinker were prepared, after much difficidty, in sufficient

amounts to make sufficient tensile specimens to allow breaking at

periods as late as one year. These constitiients were tested, not only

alone, but when mixed in about the proportion . as found in normal
EEPOET OP DIEECTOR OF BUEEAU OP STANDAEDS. 115

cements. Furthermore, the rate of hydration was followed by frequent microscopical examinations and the amounts of hydration determined by determ^inations of the amounts of T\'ater chemically combined. The results obtained confirm in almost every detail the deductions and predictions made in the paper ali-eady issued.

Clinkering Temperature of the Raw Mixes Used by Portland Cement

Manufacturers.

Owing to the nature of the flame used in the manufacture of Portland cement, it is almost impossible to determine the temperature at

which the raw mix is heated to clinker. This flame is in the nature

of a cone surrounded by partially burning coal dust which almost

entirely obscures the clinker at the hottest part of the kiln. But the

temperature at which the proper combination of the various elements

of the raw. mix takes place is of great interest, especially when considered in connection with its lowering or raising produced by

changes in composition. Seventy-three raw mixes have been burned

at the same temperatures and the resulting clinker examined. This

data is now being examined in connection with the composition of the

mixes. There is also being made the melting (softening) point of

these mixes. This work is being carried on with the Pittsburgh

branch laboratory experimental kiln.

The Effect of Varying the Composition of Raw Mixes Used in

Portland Cement Manufacture.

One of the more comprehensive studies of the Pittsburgh branch

of the Bureau of Standards is determining the effect on the general properties of Portland cement of changes in the composition,

Avhich carries with it the determination of changes in the kind and

amounts of the various constituents normally present. In this investigation 74 different cements have been made in the experimental

plant of the Bureau. These have been examined petrographically,

chemically, and their strength prodiicing properties determined—as neat cements, mortars, and concretes. The 180-day specimens of all

the cements have been broken, and consequently it will be possible to

publish the results of the investigation, though specimens have been

made for much longer periods which will entail the issue of the

supplemental papers.

There have been included in this investigation three series of burnings, of which it is thought advisable to issue the results separately.

One of these deals with white Portland cements, which differ from

normal cements largely in their very low iron-oxide content. To

make the investigation a little more comparative, there will be

included some results obtained from burnings of very low alumina

and high iron-oxide content.

The other two series deal with the important matter of the magnesia content of Portland cement. In these series there are burnings

of cement of very low magnesia content and of a content as great as 25 per cent. It may not be anticipating too much to say that the

limits for the magnesia content as specified in all standard specifications are well within the amounts which produce any injurious

effects.
116 EEPOET OF DIRECTOR OF BUREAU OF STANDARDS.

Suitability of Various Clays, Limestones, etc., for Making Portland

Cement.

There are frequent demands made upon the Pittsburgh branch of

the Bureau for the rendering of an opinion in regard to the availability of various materials for the manufacture of Portland cement.

However, the Bureau has not yet made any detailed investigation of

this character for the public, since when the inquiry is answered by a

general statement in regard to the cost of building a new cement

manufacturing plant and placing a new brand upon the market no

further information is wanted. It is not generally understood that a

deposit of raw material sufficiently large to last for 20 years for a plant turning out not less than 1,000 barrels per day—which is the

smallest plant unit that would make adequate returns on the investment—is absolutely necessary. The deposit should also be examined

carefully by a geologist to determine its uniformity in composition,

since lack of this would produce excess cost of manufacture and

other difficulties resulting in a lack of uniform cement. While the

Bureau is very willing to make trial burnings of raw materials, it

advises first a careful survey of the deposit, the determination of the

likelihood of interesting sufficient capital in the proposition, and a survey of the neighboring market.

Investigation and Testing of Cement, Concrete, and Stone.

The work in the cement section is of three kinds

(a) The determination of the physical properties of cements, conci'etes, sands, crushed stones and gravels, building stones, plasters,

drain tile, the investigation of the durability of these materials under

various conditions, and the investigation of testing methods.

(h) Special investigations of the above and other similar materials at the request of Government offices to determine as to whether

they are satisfactory under special service requirements.

(c) The testing of samples of cement submitted by various Govei'nment offices to determine as to whether the cement meets the

requirements of specifications upon which it is purchased, together

with sampling of cements at the point of manufacture and supervision of shipments under Government seal.

Durability of Concrete in Alkali Waters.

This investigation 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 re- ceived for information on the subject. The investigation is con- ducted in cooperation with the Reclamation Service, the drainage

division of the Department of Agriculture, and the Association of

American Portland Cement Manufacturers 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 imder the Bureau's supervision were installed in concentrated alkali soils in Colorado, Montana, Wyoming, Arizona, Washington, New Mexico, and Utah. The

results of the first year's tests published in Technologic Paper 44

show that concrete will disintegrate in some of these soils unless the
EEPORT OF DIRECTOR OF BUREAU OF STANDARDS. 117

best of materials are used and special care is exercised in the fabricating of the concrete. Additional tests are to be made from year to

year and the report amended as results are available. As an extension of this work short concrete columns are to be fabricated and

installed during the ensuing year on projects in Colorado, Wyoming,

Nevada, South Dakota, Montana, and New Mexico. These are made

under various conditions and are to be inspected after exposure for

various periods.

Standard Cement Sieves.

As a result of the further investigation of the standard 200-mesh

sieves results of which were published in Technologic Paper 42, it Avas found desirable to change the specifications for standard sieves

and require a given uniformity when tested with a standard fineness

sample. This modification of specifications has benefited the testing

laboratory by insuring greater uniformity of results.

Standard Fineness Sample.

As a result of requests for a standard fineness sample which could

be used by laboratories for checking their sieves and operators, an

investigation was made of the suitability for this purpose of various

materials, such as ground quartz, alumina, burned clay, cement, etc. This investigation resulted in the adoption of such a sample which

is now available to the public in two grades. There has been considerable demand for these samples since their preparation in December, 1914.

Effect of Fine Grinding of Portland Cement.

There has been much discussion as to the value of fine grinding of

cement, the tendency being to require finer grinding, although little

is laiown as to its elfect. On this account it has been deemed advisable to investigate the effect of the fineness of cement on its strength

and other physical properties.

In connection with these investigations it was necessary to develop

an apparatus for the purpose of separating in quantity the " flour " of Portland cement from the coarser particles. Three grades of

fineness are being obtained with the separator, the coarsest of which

readily passes the 200-mesh sieve. Several brands of Portland ce- ment are also being reground to various degrees of fineness to be

tested in concrete. It will probably be a year or more before conclusive results will be available.

Granular Analysis of Cement.

Investigations have been continued with the granulometric analyzer. Much work has been done with the object of making the

analyzer more compact and convenient for laboratory use. The

proper shape of bulb, the effect of abrasion of particles on the results

of analyses, effect of differences in specific gravity of cements on the

sizes of particles blown off and the least height of stack that may be

used, were investigated. In connection with the specific gravity and

height of stack investigations, more than 10,000 cement particles were

measured with the microscope. The results of these investigations

have been reported in Technologic Paper 48.
118 REPOET OF DIEECTOR OF BUREAU OF STANDARDS,

In addition to work done with the analyzer as a part of the programs of investigations by the Bureau of Standards, work has also

been done in connection with investigations by several cement companies.

" Flour " determinations have been made on samples of litharge,

red lead, hydrated lime, ground sand, etc. The air analyzer may be said to supplement sieve determinations

of fineness, being capable of producing much finer separations than

those obtainable with the 200-mesh sieve. On account of the lack of

uniformity in the size of openings of the 200-mesh sieve the determinations by the air analyzer are more accurate as to the limiting size

of particle in each degree of fineness obtained.

Stucco and Plaster Investigation.

A series of tests, primarily to determine the comparative durability of various types of plastered metal lath on exterior walls,

was 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 was planned, the program of which

was put into the hands of an advisory committee consisting of representatives from the Government, engineering societies, the Associated Metal Lath Manufacturers, the Association of American Portland Cement Manufacturers, the Gypsum Industries Association, the

National Lime Manufacturers Association, the Hollow Tile Manufacturers Association, and a number of plastering contractors. The

recommendations of this conunittee have been followed in the execution 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 being constructed of terra cotta hollow tile, monolithic concrete,

brick, gypsum block, plaster board, and wood and metal lath, and

will be plastered with a number of typical stuccos. The work will

be carried out under the supervision of the advisory committee, and

it is anticipated that the finished panels will represent the best ex- amples obtainable of exterior stucco construction. The stucco panels

will be completed in the fall of 1915; later the interior of the structure will be available for tests of interior plasters on walls and ceilings. Eesults will not be available for a year or more.

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 straingauge measurements on concrete roads and pavements with the

ultimate aim of determining the most effective distance for the

spacing of transverse joints in concrete. The results obtained show

that changes in the moisture content of the concrete has greater

effect upon the volumetric expansion or contraction than the normal

atmospheric variation in temperature between seasons. The maximum expansion of concrete occurs in the early spring and maximum contraction in midsummer. Further measurements will be

needed to determine the absolute quantitative effect of moisture and

temperature conditions.
EEPORT OF DIRECTOR OF BUREAU OF STANDARDS. 119

Strength of Reinforced Concrete Structures.

An investigation of full-size concrete structural members of

various design to establish the laws governing their behavior was

inaugurated. An advisory commmittee has been organized, composed of prominent engineers expert in concrete design, to act with

the Bureau in the execution of the program. A thorough and ex- haustive series of tests will be made on numerous full-size members

of reinforced concrete construction in the form of both individual

and composite structures. The work is in a formulative stage and

no results are yet. available.

Value of the High-Pressure Steam Test of Portland Cement.

The investigation of the value of atmospheric and high-pressure

steam tests as a means of determining the soundness of Portland

cement has been continued and the results available to date have

been published as Technologic Paper 47. This test has been ex- ploited during the past few years by some engineers and widely

discussed in the technical press. The results obtained to date indicate that cements meeting the requirements of this test are no

stronger or more durable when employed in concrete under normal

conditions than cements passing the present standard cement specifications but failing to pass this test.

Physical Properties of Sand-Cements (Silica Cements).

During the past two years a study of the physical properties of

several sand cements has been made. This work was continued this

5'^ear and the results to date have been collated and will be published

in the near future. Cements of this character have been extensively

used on Government work. The tests to date indicate that concrete containing sand cement as the binding material is inferior

in strength to concrete containing the same amount of standard

Portland cement. The difference in strength of the two concretes

becomes more marked as the ratio of the cement to aggregate decreases. Value of Various Materials as Concrete Aggregate.

In cooperation with State geologists and others, representative

samples of mine tailings, crushed slag, sands, gravels, and stones are being obtained for test to determine their suitability as aggregate for

concrete mixtures. Many inquiries are received concerning the value

of these materials. Results of the investigations will probably be

published in State reports and subsequently in Bureau papers as the

results accumulate.

Compressive Strength of Portland Cement Mortars and Concretes.

A study was completed of 20,000 tests of Portland cement mortars

and concretes collated from the many investigations made by the

Bureau of Standards and the structural materials laboratories of

the Geological Survey, which were transferred to the Bureau of

Standards in 1910. The results show that several of the generally

accepted methods for proportioning concrete mixtures are incorrect

and that certain precautions are necessary in the fabrication of concrete to ensure a product of known quality. The effect of variation
120 EEPOBT OF DIRECTOE OF BUREAU OF STANDARDS.

in the quantity of cement used, the effect of different exposures while

hardening, the effect of aging, etc., is discussed. The relative value

is shown of various aggregates such as gravels, limestones, granites,

trap rocks, cinders, sands, and stone screenings, also the relative

value of rounded and sharp-grained sands. Proper methods for

testing and selecting aggregates are also suggested.

Effect of Sea Water on Concrete.

The investigation of the effect of sea water on concrete has been

continued by inspecting many concrete structures along the Atlantic

and Pacific coasts of the United States, the coast of Nova Scotia and

NeAV Brunswick, by careful investigation through physical examination and tests of structures which had failed, and collating information on the condition of concrete structures exposed to sea water in

various ports of the world. These data are being obtained through

the various consular agents, and reports have been received on a large number of structures. It is anticipated that during the ensuing

year a report will be prepared showing the conditions under which

concrete should be used in order to have permanency under sea-water

exposure. The results of this investigation will be of value to the

Government and all engineers interested in marine construction.

Fusion of Concrete.

The Bureau was asked to investigate the reported fusion of concrete in a burned building. Since the fusion of concrete had never been observed under such conditions, an investigation was made. It

was found that the concrete had apparently fused in several of the

buildings where the fire was known to have been of exceptional

severity and long duration. Laboratory investigation upon samples

of unexposed concrete from the same buildings showed that the concrete would fuse at a temperature of approximately 1,240° C. This

comparatively low fusion temperature was due to the trap-rock aggregate. It was evident from the melted steel that temperatures

were obtained in portions of the buildings well above that required

to cause fusion.

Dusting of Concrete Floors.

Experiments have been started to determine a suitable material

for treating the surface of concrete floors to prevent dusting and

increase their durability. This work is part of a more comprehensive

investigation which is now being outlined to determine proper

methods of construction which will mitigate dusting. An abrasion

machine has been designed for testing flooring materials which it is

believed will give results comparable with the actual wear on floors,

and plans have been made for extensive tests on various flooring

materials. Results of this investigation probably will not be available for a year or two.

Investigation of Concrete Aggregate for Panama Canal.

A rather exhaustive series of tests was made of the aggregate at

present used in the concrete work on the Panama Canal. Due to a decrease in the demand for material of this character on this project,

it was planned to eliminate all but one of the plants producing concrete aggregate, but it was desired to retain that one which produced
REPORT OF DIRECTOR OF BUREAU OP STANDARDS, 121

the material yielding the most dense and strongest concrete. With

this in view several tons of the available aggregates were submitted

to the Bureau and tests were made, with the result that it was rec- ommended to employ Ancon crushed stone and screenings. Experiments were also made on concrete containing crushed rock up to 4

inches in size, and it was found that material of this Irind increased

the amount of inert material that could be added to the same amount

of cement without impairing the strength of the resulting concrete.

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. A concrete of this character was desired as a substitute for willow mats for use in revetment work on the Mississippi

River. The decline in the supply of willows available for this purpose necessitated the finding of a suitable substitute. A large number

of experiments were made and results that are promising have been

obtained. It is contemplated to continue the work along the present

lines and publish the results in the near future.

Stone Investigation.

In connection with the cooperative investigation of building stones,

machinery has been installed for cutting and grinding test pieces, and

representative samples of stone have been collected, in cooperation

with the Geological Survey and Bureau of Mines, from 80 quarries.

Thirty samples of marble and limestone and 86 samples of other

stones, totaling 2,784 specimens, have been tested to determine compressive, tensile, transverse strength, on edge and bed, specific gravity,

absorption, hardness, staining quality, and resistance to frost action.

A card-index system for filing stone records has been worked up

and all available tests made at this Bureau and other laboratories

have been collated and filed therein for ready reference. A paper

containing the available data will probably be prepared for publication during the ensuing year.

Investigation of Fire Protection for Steel Columns.

The Bureau has cooperated with the Underwriters Laboratories

in developing the program of fire tests of various types of steel columns under load. Preliminary designs of protective coverings were

prepared and tentative suggestions made as to the concrete and mortar mixtures and materials to be used. Several conferences were held

and further assistance rendered in the development of the final program. This investigation contemplates tests of a large number of

full-size structural steel columns, protected by commercial coverings

such as concrete in various forms, tile, and gypsum. The tests will

probably be made during the ensuing year.

Investigation of the Fire-Resisting Qualities of Partition and Supporting Walls.

Designs were completed for the construction of a testing plant

including a furnace and 12 panel frames for making fire tests of

partition and supporting walls. The frames are heavy steel I-beam

and plate sections 17 feet long by 13 feet high and will accommodate
122 KEPOET OF DIRECTOR OP BUREAU OP STANDARDS.

a wall 12 by 16 feet up to 12 inches in thiclmess. The furnace is designed to have a temperature uniformity within 40° for any two

points on the wall for temperatures between 1,400° and 2,500° F.

The testing plant will also be provided with fire pump and equipment to give a water stream up to 80 pounds per square inch pressure

through a 1-^-inch nozzle. Most of the equipment has been ordered

and part of the construction work completed, but the plant will not

be ready for operation until about January, 1916.

The Value of Tufa Rock and Volcanic Ash as a Material for Admixture with Portland Cement.

At the request of the United States Engineer Office at Honolulu,

Hawaii, an investigation was started to determine the suitability of

certain tufa rock and volcanic ash, found in that territory, for use

as a material to be mixed with Portland cement to produce a cheaper

but satisfactory cement for building purposes. The materials have

been received and the tests are in progress. It is expected that a report of these tests will be published during the coming year.

Investigation of Integral Waterproofing Compounds.

In 1912 a number of cement stucco panels approximately 3 by 12 feet

in size were erected in which various integral waterproofing compounds were incorporated. These panels have been exposed to the

weather and observations made from time to time. Their present

condition indicates that none of the so-called integral waterproofing

compounds have appreciable value ; some of them are deleterious and

cause cracking and disintegration. About 10 per cent by volume of

hydrated lime appears to appreciably decrease the water absorption

property of the stucco and has no deleterious effect. This work is being continued by the erection of several large panels containing

waterproofing compounds in connection with the general stucco investigation. Plans have also been formulated for the organization

of a committee to outline a comprehensive series of tests on the integral method of waterproofing against water pressure. Many inquiries are received on this subject and it is of much concern to all users of cement.

Routine Cement Inspection and Testing.

Cement was inspected during the year at 12 different cement mills

located in Virginia, Maryland, Pennsylvania, and New Jersey. The

inspection work included the taking of samples, their testing, and

subsequent inspection of packing and shipping. A total of 10,125

samples were tested for the Navy and War Departments, Bureau of

Lighthouses, Panama Canal, Supervising Architect's Office, District

of Columbia, Lincoln Memorial Commission, etc. Inspection was

made of 480,808 barrels of cement for shipment to Panama and

207,877 barrels for shipments to Government departments in the

United States, for use in the construction of Federal buildings, river

and harbor improvements, etc. Cement was inspected for three companies for the Government of

Argentina. This included the sampling and testing of 91 samples,

approximately 61,400 barrels. It was necessary that this cement
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 123

should pass the United States Government specifications for Portland cement before it could be accepted by the Argentine Eepublic.

At the Pittsburgh branch laboratory the routine testing of cement

for the public has been very slight ; but for Government uses it has

been so great that it was necessary to place local inspectors at three

different plants, who take charge of the sampling and shipping alone,

the actual testing being done as usual at the laboratory. It is gratifying to note that the quality as furnished has improved very markedly. Thus, out of 329,000 barrels sampled, it was necessary to reject

only 14,600 barrels. During the previous year it was necessary to

return to the manufacturer more than twice this amount.

Miscellaneous Investigations and Tests.

A total of 306 samples were tested consisting of sands, screenings,

gravels, stones, asbestos roofing boards, sand-lime brick, gypsum,

magnesite cements, composition flooring, concrete, cement accelerators, etc. Twenty-three commercial waterproofing compounds were tested for

the Lincoln Memorial and Arlington Memorial to determine their

efficiency in preventing moisture and stains from penetrating the

pores of marble. Six samples of marble were submitted to abrasion

tests to determine the one most suitable for use in the floor of a building which had a floor failure due to severe service. Four commercial types of composition flooring were tested for the United

States Marine Corps to determine their suitability under special conditions. Three samples of sandstone were investigated to determine

their resistance to fire.

Information Furnished as to Cement and Concrete.

Many inquiries were received during the year from architects, engineers, contractors, and builders who sought information concern- ing 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 walls and ceilings, the relative value of various

concrete aggregates, the cause of failure of magnesite composition

floors, methods of preventing the dusting of cement floors, methods of

designing concrete road slabs, suggestions for building code requirements, durability of cement drain tile, the physical properties of

marbles, specifications for stucco, fire-resisting properties of structural materials, the corrosion of metal lath, reinforcement of gypsum

plasters, 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 stones, the cause of fail- ure 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 mamifacturers,

commercial testing laboratories, requests were received for informa-
124 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

tion on the accuracy of sieves, the physical properties or concrete, the

value of fine grinding, the value of silica cements, cause of failure of

drain tile, the interpretation of cement specification, value of sieve

agitating machines, quick hardening concrete, standard fineness samples, standard methods of testing, etc.

Publications on Cement and Concrete.

The following papers were prepared during the year : Technologic

Paper 42, " Standardization of No. 200 Cement Sieves ; " Technologic

Paper 44, "Investigation of the Durability of Cement Drain Tile

in Alkali Soils;" Technologic Paper 47, "The Value of the HighPressure Steam Test of Portland Cements ; " Technologic Paper 48,

"An Air Analyzer for Portland Cement ; " and Technologic Paper

58, "The Compressive Strength of Portland Cement Mortars and

Concretes."

The Purification of Clay.

It has been shown that very small amounts of caustic soda, car- bonate of soda, and silicate of soda contained in the water employed

in washing clays biding about a sharper separation of the clay and

its impurities. The process has been installed in one plant and is

being tried out by others. The product thus purified is superior in

quality to that obtained by the usual process.

The object of increasing amounts of the same reagents in reducing

the quantity of water used in casting slips has been worked out for a number of American clays. A simple efflux tube for determining

the fluidity of slips used for casting clay wares has been designed.

In this manner the addition of the chemicals can be controlled in

factory practice.

The strilring effect of sodium-oxalate additions to Florida kaolin

in reducing the water content have also been studied.

Porcelain from American Raw Materials.

Experiments conducted both from the laboratory and shop standpoint have demonstrated, first, that the domestic kaolins can be purified so as to result in ware of excellent whiteness and, second, that

from American kaolins, ball clays, feldspar, and flint a high grade

of chemical porcelain, as well as of hard fire table ware, can be

produced. Cooperation was carried on with a number of American

pottery plants.

American Raw Materials Replacing the Imported Glass Pot and

Crucible Clays.

An exhaustive study of some 15 imported and more than 100

domestic fire clays carried on in cooperation with manufacturers of

glass pots has been carried on during the past year. The distinctive

properties of the foreign clays were clearly defined and it was sought

to replace them by mixtures of American clays. It was shown that

while no single American clay found so far possessed all of the qualities of the best European plastic materials satisfactory results can

be obtained by the use of a mixture of several domestic clays. The

present work demonstrates that the importation of clays for the purposes of the glass and crucible industries is unnecessary, since there
BEPOBT OF DIRECTOR OP BUREAU OF STANDARDS. 125

is a considerable number of excellent clays in Missouri, Kentucky,

Tennessee, Pennsylvania, New Jersey, and Illinois available for this

work.

Mixtures of Easily Vitrifying and Refractory Clays with Reference

to their Rate of Vitrification.

In many industrial plants it is necessary to oppose the rapid vitrification of a readily fusible clay or to accelerate it when an inherently

more refractory material is used. Work which was done with mixtures of clays representing the opposite types and the extent to

which they interact and modify each other was demonstrated.

Vitrification of Clays and Electrical Conductivity.

It has been shown that the softening and partial fusion of clays

when being fired is coincident with a marked increase in electrical

conductivity.

Softening of Porcelain at Kiln Temperatures.

Previous work along this line has been continued and completed.

The specimens which liave passed through the often repeated heat

treatment are being studied microscopically, since they approach

equilibrium conditions very closely. The universal constitution of

porcelains will thus become known.

Enamels and Colors.

Owing to the failure of the European supply a number of color

and enamel compositions for clay ware and glass have been prepared

and placed at the disposal of maimers of such material.

Enameled Iron and Steel,

A suitable furnace has been erected and work has been begun on

the study of metal enamels Avith special reference to enamel coating

resistant to chemical reagents and to abrasion.

Optical Glass.

This country is entirely dependent on Europe for the supply of

glass used in the manufacture of all kinds of optical goods. For this reason the study of the manufacture of optical glass was begun.

Suitable furnaces and apparatus were installed. The work is now

under way, but no completed results can as yet be reported.

Properties of Halloysite.

A peculiar clay-like mineral occurring in southern Indiana in large

quantities, called indianite, a modification of halloysite, was ex- amined with regard to its physical properties and composition. It

was found suitable for the manufacture of high-grade refractories

and appears to be adapted even to pottery making.

Silica Brick.

The properties of silica brick used in furnaces are being studied

with special reference to their permanent expansion and change in

crystalline structure.
126 EEPOET OF DIRECTOR OP BUREAU OF STANDARDS.

Testing of Fire Bricks.

In cooperation with the American Gas Institute and the American

Eefractories Association considerable work has been done in testing

the resistance of fire clay products used in gas and coke oven plants

to high heats and to loads at furnace temperatures. This information

is to be used in working out specifications for refractories used in

such important industrial plants.

Hollow Building Tile.

During the past two years a study of the physical properties of

tile have been made in cooperation with manufacturers. Numerous

experiments have been conducted to find the relative resisting power

of different size tiles. The elastic coefficients have been determined in

several hundred specimens, chiefly in order to determine the amount

of variation that may be expected in the modulus (the ratio of load

on tile to its compression under load), this information being desired

by engineers in connection with the designing of tile walls and the

ultimate loads on different grades and shapes. The relative effi- ciencies with respect to loading for different arrangement of bracing webs have been determined, and the comparative advantages of

laying tile in different position in walls have also been studied. Some

experiments were carried out to find the relative stiffness of different

walls against lateral pressures, different types of wall construction

being used, the walls always being of sizes comparable to those used

in practical construction.

Experiments on Strength of Large Brick Piers.

This investigation has been conducted in cooperation with the

National Brick Manufacturers' Association to determine the physical

properties of large brick piers when under various loadings up to

failure. The brick for the piers were selected in such a wa}^ as to be

representative of the manufacturing output of the important geographical districts east of the Mississippi; these being the eastern

district, covering New York and adjacent territory; the Pittsburgh

district, covering western Pennsylvania and Ohio; the Chicago and

Galesburg districts; and the southern brick manufacturing belt.

Vitrified, hard, and common brick were used in the piers and they

were laid up in various kinds of mortar, chosen to be representative

of engineering and architectural practice. The piers were 2^ feet

square and 10 feet high. The elastic constants of the piers were

determined and a study made of the causes which most influence

failure with respect to the grade of brick, type of mortar, bond,

manner of laying the brick, and age of pier, with a view to defining

the best load-carrying efficiencies of actual piers used in modern

practice. Numerous supplementary tests are being carried out on

the individual brick to determine independently their physical properties. These included a series of tests to determine the ratio of the

strengths of bricks tested flat to those tested on edge. In this series

three grades of bricks were used, one half of these being tested flat,

the other half on edge, making a total of 90 individual tests. Thirty

of the large piers have already been tested.
EEPOET OF DIRECTOR OP BUREAU OF STANDARDS. 127

Investigation of the Resisting Power of Soils.

A cooperative investigation has been taken up the past year conjointly with the committee of the American Society of Civil Engineers to determine the resisting properties of soils under the various

conditions which arise in engineering practice. Numerous factors are presented in connection with the design of foundations and re- taining walls, the bearing power of piles, the influence of which

properly can usually be determined only experimentally by laboratory methods. Another class of factor arises in connection with the

investigation of the laws of flow of plastic materials, as in the case of clay-working plants, or in the phenomena connected with the flow

and pressure of grain in elevators. A still further class of phenomena presents itself in connection with the laws of controlling the

movement of large masses of earth, as in the case of avalanches, or

in the engineering problems of subsidence of earth, the action of

freezing in forcing over large walls, etc. The experiments thus far

conducted have been largely for the purpose of determining to what

extent this branch of investigation will lend itself to laboratory

methods, as against the use of statistical methods or judgment applied to field observations, such as has largely been done in the past

by many engineers. Various physical coefficients are being found in

these connections for different media which simulate actual earths,

such, for example, as the density in relation to the pressure, the coefficient of frictions between the earths and bodies " immersed " in

them, and the ratio of induced lateral pressure to vertical pressure,

with a view to determining what practical range may be expected

in these coefficients when the experiments are repeated, either under

identical conditions or otherwise. The purpose ultimately is to secure

definite data for applying to problems of engineering design after a

suitable practical classification of known earths has been determined.

Cooperation with Technical Societies and Institutions.

The Bureau cooperates with technical organizations and educational institutions by contributing papers and articles to their transactions and assisting in giving short industrial courses for the benefit

of manufacturers. Very clos6 cooperation is being maintained with

the National Brick Manufacturers' Association in the testing of large

brick piers, with the American Ceramic Society, the American Society for Testing Materials, the National Paving Brick Manufacturers' Association, and a number of State organizations.

Information as to Clays and Clay Products.

Requests for information come from a large number of present

and prospective manufacturefs, and in many cases personal visits are made at the laboratories with specimens of raw materials or finished

products. This phase of the work is growing more and more in

scope and volume. In unusual cases trips have been made to the

plants at the expense of the manufacturers.

Clay Testing.

A considerable number of clays have been tested and particular

attention was paid to deposits which seemed to be promising raw

materials for the pottery and refractory materials industries. Koa-
128 KEPORT OF DIRECTOR OF BUREAU OF STANDARDS,

lins, plastic clays, shales, and surface clays were tested, coming from

Florida, Tennessee, North Carolina, Texas, Georgia, Alabama, Missouri, Illinois, Pennsylvania, Maryland, Ohio, Indiana, and other

States.

Testing of Clay Products.

Physical tests of fire bricks, building tile, building and paving

bricks, and electrical insulators have been made throughout the year

in considerable numbers for Government departments, particularly

the Panama Canal, as well as for the public at large.

Method of Measuring Plasticity of Lime.

Plasticity is by far the most important property of lime, frequently

governing not only the use but also the price of the material. It is therefore extremely important that some method of testing for this

property be established. Following the theory for the behavior of

plastic bodies under load, a method of test has been developed and

a machine designed and built for the purpose. The lime to be tested

is mixed with the proper amount of water to form a putty and

molded. The mold is immediately removed, and sufficient load is

applied to the specimen to cause rupture. The rupture occurs along

certain well-defined planes. Measurements of the angle which these

planes make with the vertical, and of the load applied, give sufficient

data to substitute in Merriman's formulas. The values of the " coefficient of internal friction " and of the " coefficient of cohesion " can now be calculated. The first tells whether the lime is sticky or sandy,

the second whether it can be spread out into a thin coat or will tear

easily under the trowel. The method has been applied to a large

number of samples of hydrated lime, with satisfactory results.

Improvement of Plasticity of Hydrated Lime.

If hydrated lime is mixed with water, the putty formed will not

be, in general, so plastic as that made from quick lime. This lack

of plasticity is due to the presence in hydrated lime of what is

known as "burned hydrate." This material differs physically, chemically, and optically from hydrated lime. The evidence at hand leads

to the belief that it is a basic hydrate, which can be formed either

during the process of hydration, when the lime may not be given

a sufficient amount of water ; or, the heat generated may be sufficient

to decompose partially the hydrate which has already been formed.

Attempts are being made to eliminate the production of this material by changing the design of the machine used for hydration.

Bonding Material in Sand-Lime Brick.

Sand-lime brick consists essentially of sand bound together by a compound of lime and sand which is formed by the action of steam.

This compound has been loosely designated as a " hydrated calcium

silicate." Since the properties of the brick depend largely on the

behavior of the bonding material, it is desirable to know just what

this substance is and how it will be affected under different conditions. The material was prepared by mixing pure lime and pure

silica in the proper proportions and treating them with steam under

high pressure. The resultant product was found to contain one mole-
KEPOET OF DIBECTOE OF BUEEAU OF STANDAEDS. 129

cule of lime combined with one molecule of silica. There is also some,

water held in chemical combination, but this seems to vary somewhat

with the method of preparation. The silicate is attacked very readily

by carbon dioxide, but this action resulted in an increase in the

strength of the specimens treated.

Introduction of Carbon Dioxide During the Steam Treatment of

Sand-Lime Brick.

In view of the effect of carbon dioxide on calcium metasilicate, it was thought possible to improve the strength of sand-lime brick by

introducing carbon dioxide into the cylinder where the bricks are cured with steam. This process was patented, but is not now in use. There seems to be no doubt as to the results obtainable, the question

being largely one of overcoming mechanical and economic difficulties.

Method for Estimating the Amount of Free Lime in the Presence of

some Silicates and Aluminates.

When examining the calcium silicate found in sand-lime brick,

mixtures of lime and silica were treated with steam. It was neces- sary to determine how much of the lime was left uncombined. The

silicate is so readily decomposed that no ordinary method of analysis

could be used. The method finally decided upon was to suspend the

sample in a mixture of 2 parts of glycerin and 10 parts of alcohol,

and titrate the lime with a solution of ammonium acetate in alcohol,

using phenolphthalein as an indicator. The method was found to be

accurate in the presence of all the compounds which might be present

in sand-lime brick. It is accurate in the presence of tricalcium aluminate if especial precautions are taken to eliminate all water. It is

not available in the presence of tricalcium silicate.

Information About Lime and Sand-Lime Brick.

The questions asked the Bureau by manufacturers of lime deal

mainly with plasticity or with plant equipment. One man wants to

know whether his lime is more plastic than another's. One wants to

Imow how to improve the plasticity of his hydrate. Information is

desired as to the type of kiln which can be used for burning lime

when oil or coke is used for fuel. Consumers desire information

mainly in regard to the kind of lime which should be used for a given purpose and Avhere such lime can be obtained. The Bureau is frequently called upon to examine samples of limestone and report

on it to prospective purchasers of quarries. Miscellaneous inquiries

include the cause of hard lumps or of colored matter in the lime and

the availability of oyster shells, marl, or coral as a source of lime.

The National Lime Manufacturers' Association recently established

the Hydrated Lime Bureau for the purpose of advancing' the interests

of hydrated lime. All of their advertising literature is submitted to

the Bureau of Standards before publication, in order that no state- ments will go out to the public which can not be substantiated.

Requests for information relative to sand-lime brick are general

in their nature, as, " What is sand-lime brick, and is it safe to use

it? " To answer such questions a circular describing the process of

manufacture and properties of the material is now in course of

preparation.

10739°—15 9
130 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

It is desirable wherever possible to hare first-hand information

about the condition of the industry and that the manufacturers,

dealers, and consumers become personally acquainted with the work

of the Bureau. In line with this policy, all of the lime plants now

operating in Washington and Oregon were visited. Especial attention was paid to the equipment of the plants, their efficiency and

capacity, the quality of lime produced, and the market conditions.

It is hoped that the acquaintances formed with manufacturers, dealers, and consumers will result in mutual advantage to them and to

the Bureau and that they will feel more inclined to place their problems before the Bureau for solution. Thus the Bureau will be better

able to understand their difficulties.

Temperature of Decomposition of Gypsum.

Plaster of Paris, or " hard wall plaster," is an important article in

the building trades. It is obtained by the calcination of gypsum.

There are, however, other jDroducts which can be foi-med by calcination, and the one which is produced depends mainly on the temperature used. Since these products differ materially in their physical

properties, the temperature of calcination is an important commercial factor. A sample of pure gypsum was heated to constant weight

at different temperatures, and the material produced was examined.

At 110° to 120° C. it lost three-fourths of its water, the product

being plaster of Paris. At 140° to 150° C. it lost the rest of the

water. The material left was " soluble anhydrite." When mixed

with water this material sets as quickly as plaster of Paris and produces a much stronger specimen. If the dry material is exposed

to the air, it will quickly absorb water and revert back to plaster

of Paris. At about 350° C. soluble anhydrite changes to ordinary

anhydrite without any loss of weight. This anhydrite is practically

inert to water and will not set in any reasonable length of time.

Effect of Compression in Baling of Raw Cotton.

An investigation has been commenced to determine the effect of

compressing raw cotton to densities up to 50 pounds per cubic foot.

At the present time American cotton is compressed to densities from

20 to 30 pounds per cubic foot, while cotton put up in Egypt and

India is packed to a density of about 40 pounds per cubic foot. If

cotton can be compressed at high densities without injury to the

fiber, much smaller bales would result. The smaller bales would thus

make handling less difficult, reduce the cost of transportation, lessen

the cost of covering the cotton, and great saving would result to

the railroads, steamship lines, and warehouses. This investigation

was urgently requested by the General Managers Cotton Association

of the Southeast, and it is hoped that facts will soon be obtained.

The results of such an investigation should be very helpful to all

that handle raw cotton.

Manufacture of American-Grown Flax.

An investigation was made of linen yarns and fabrics manufactured from domestic flax. Practically all the linen consumed in the

United States is imported. One concern situated in the Middle West

has attempted to grow flax and manufacture linen materials upon
BEPOBT OF DIRECTOK OF BUREAU OF STANDARDS. 131

a commercial scale and to compete with the foreign goods. The

Bureau has obtained samples of the domestic product and compared

them with similar imported materials. Comparison of the results

of physical tests of yarns, household linen, and dress goods showed

that the quality of the domestic material was equal to that of the

imported.

The results have considerable significance in that under proper

supervision flax can be grown in this country to produce fiber which

could be utilized in the manufacture of many linens now imported.

Identification of Textile Fibers.

An important investigation has been planned and some work done

to determine methods of fiber analysis which will unmistakably

identify certain fibers. This investigation will require a careful

study, as all the properties of the various fibers used in textile fabrics

will probably need to be examined. This study is of growing importance on account of the many new processes to which fibers are now subjected.

Automobile-Tire Fabric Investigations.

The cotton mills manufacturing automobile-tire fabric and the

dealers in this cloth have in many instances developed their own

methods of tests. The Bureau was urgently requested to develop and

to standardize methods for testing this material. In cooperation

with several mills the Bureau developed a method for determining

tensile strength. This method has been adopted at least for one year

by the textile committee of the American Society for Testing Materials. Several members of the society are some of the largest users of tii'e fabric. Many hundreds of tests have also been made to determine better methods for selecting tensile strength test specimens

and for the determination of weight, threads per inch, elongation

of fabric, moisture, crimp or yarns, etc. An extensive investigation

upon the comparison of various tire fabric tensile-strength testing

machines was made during the year. The results were of value in

that they showed the inaccuracy of machines in use. One machine

was found to record consistently incorrect readings of about 40

pounds, the tests being made upon fabric giving breaking stresses of

about 220 pounds.

Adulteration of Textile Materials.

An important field of research is that of ascertaining the extent

to which textile materials are adulterated and misrepresented. The

public is becoming more and more concerned and often demands a guarantee that the goods purchased are as represented. Many tests

by the Bureau during the past year conclusively illustrates the need

of an extended investigation. The present work will be continued

during the next fiscal year and, if possible, the variety of goods analyzed will be greatly enlarged.

Moisture in Cotton Fiber.

In response to several requests a preliminary investigation was

made upon the rate and quantity of moisture cotton fiber would

absorb or give up under various atmospheric conditions. A special
132 KEPOET OF DIEECTOR OF BUEEAU OF STAJTDAEDS.

instniment was cleA'ised and constructed in order to make accurate

determinations. The preliminary results indicate that much valuable information should be obtained by the use of this instrument.

The work has only recently been undertaken, but will be continued

during the coming year. The results of this investigation will contribute toward a better knowledge of the important action of moisture upon textile materials relative to its weigh.

Physical Properties of Spool Thread.

A large number of tests were made upon common spool threads ex- tensively used in the household and by garment manufacturers.

Spool threads ranging in size from Xo. 12 to Xo. 70 were tested for

tensile strength and number. One spool marked " No. 36 and 12,000

yards per spool" actually tested No. 28 and 11,500 yards of thread.

It is hoped that an extended investigation upon this subject can be

made the coming year.

Tensile Strength and Weight of Fabric as Influenced by its Moisture

Content.

The effect of moisture upon the strength and weight of textile

fabric has been Imown in a general way for many years. It is only

recently, however, that American manufacturers, buyers, and sellers

have realized that they should become definitely acquainted with the

moisture content of the fabric they are handling. For instance,

automobile-tire fabric (cotton) breaking at 240 pounds, with 3.5 per

cent moisture content, will have a tensile strength of 320 pounds,

with 8.5 per cent moisture present. Under these conditions of moisture there will be a difference in weight of about 1 ounce per square

yard.

Wool fabric is influenced, by the presence of moisture, in the same

direction to that of cotton as regards weight, but in the opposite

direction relative to tensile strength. In other words, wool fabric

will become heavier with additions of moisture but its tensile strength

will be less. In view of its importance, future work will cover a wide scope of testing and research.

Worsted Yarn of Commerce.

"Wool-yarn manufacturers have requested the Bureau to make a study of the oil and moisture content of the more common worsted

yarns. Considerable data have now been compiled, but a much

greater variety of yarns will be studied the coming year. Other

physical properties, such as tensile strength, correctness of yam

number, and effect of atmospheric moisture will be investigated.

Comparative Tests of Cotton and Wool Flag Bunting.

For many years wool fiber has been employed in the manufacture

of bunting in the higher priced flags. During the past year cotton

bunting and cotton flags were manufactured at about one-half the

price of the wool bunting. A series of comparative tests were made

upon several brands of wool bimting and cotton bunting. The tests included tensile strength, weight, fastness of color, and exposure to

weather conditions. The cotton bunting was superior to the wool

bunting in man}' respects: therefore cotton is being used rather

extensively for many purposes.
EEPORX OF DIEECTOE OF BUREAU OF STANDARDS. 133

The results of tests were furnished to all Government departments,

and the Bureau is informed that a considerable saving in many offices

has resulted from the use of cotton flags as a substitute for tvooI.

Scouring of Domestic Wools.

Assistance was given the Division of Animal Husbandry. Department of Agriculture, concerning the shrinkage of certain wool fleeces.

These fleeces were carefully grown under the supervision of Government experts with the view to an investigation of the yield of clean

wool and a study of the character of the staple. The Bureau scoured

35 fleeces and reported the yield of clean wool. The investigation

was done in connection with range breeding experiments that will be

continued for some years.

Determination of the Length of Textile Yarns of Commerce.

Considerable study has been made upon methods of accurately

determining any length of yarn which has been wound in skeins or upon bobbins, cops, spools, etc. A new apparatus was designed and

constructed by the Bureau, and the results of tests thus far indicate

that the instrument will be satisfactory. The first importance of this

instrument is in determining an accurate length, then by ascertaining the weight of a certain length the size or yarn number can be

calculated. The knowledge of the ya^rn number is of the greatest

importance in the manufacture of yarns and fabrics, to the con- sumer, and in the application of the duty to imported yarns. Under

the terms of the last tariff law all imported yarns are taxed at varying rates according to their yarn number. The Bureau has fiu'-

nished the Customs Service considerable information in designing

apparatus and developing better and more economical methods for

textile analysis at the various ports. Further researches will be

conducted, and it is believed that a_ method will be developed by

which many of the controversies arising in the trade can be readily

and satisfactorily settled.

Methods of Testing Twine.

A very important field of work is the drafting of specifications and

the testing of twine.

Several of the Government departments combined use more than

$300,000 worth of twine a year. The Bureau drafts the specifications

for many of these departments, and tests are made upon the deliveries

to ascertain if they comply with the requirements. Two thousand

and twenty-five balls of twine were tested dining the year.

The Post Office Department purchases twine specifying a certain

yardage and tensile strength at a definite weight. The Bureau tests the samples imder the specified conditions, and it thus enables the

price to be satisfactorih' adjusted.

Textile Tests.

The materials submitted for examination and the number of samples tested by the Bureau as routine work numbered 3.444, classified as follows : Common twine, 2.023 : imported yarn, 860 ; thread, cord,

cable, and rope, 61 ; denims, tire fabric, bags, sheeting, canvas, blankets, imiform cloth, tracing cloth, coin sacks, flag bunting, book

cloth, dress goods, cement bag fabric, shirting, gingham, etc., 500.
134 EEPOET OP DIBECTOE OF BUEEAU OF STANDAEDS.

More than 300 additional samples were tested in cooperation with

mills who assisted the Bureau in some of its investigations. These

were not considered as ordinary routine tests. The samples of material designated above do not properly illustrate the work involved, as the actual number of routine tests were

more than 33,000. Samples were submitted by Government establishments and others, and the following number of tests were made:

Post Office, 16,752 ; Custonis Service, 8,600 ; Interior, 3,084 ; Treasury,

464; Agriculture, 430; Commerce, 130; Panama Canal, 106; War,

150 ; Mississippi River Commission, 240 ; private parties, 3,240.

The number of tests increased 33 per cent over the previous year

that is, more than 10,000 tests. Information Furnished on Textile Subjects.

Many inquiries were received from automobile-tire manufacturers

and mills making tire fabric desiring information concerning the

testing of the cloth. Several mills sent the Bureau numerous data

covering many months of tests, and in return the Bureau rendered

assistance in suggesting better methods of compiling these data,

methods of tests, and necessary laboratory apparatus and its calibration. The results of the Bureau's investigations were also furnished

the mills. The Bureau's activities have led to the adoption by the

members of the textile committee of the American Society for Testing Materials of tentative methods for testing and specifications for

automobile-tire fabric.

There have been numerous requests by testing laboratories regarding tensile-strength apparatus to install for various textile tests. From the general public many inquiries were received as to simple

methods for determining adulterations, the effect of cotton mixed

with wool, employment of artificial silk as a substitute for natural

silk, jute as a substitute for flax, hemp, and wool, etc. From cotton mills information was often requested upon the influ- ence of moisture in the atmosphere when the fiber was passing through

certain processes and that of the resultant moisture in the finished

product.

The various Government departments were rendered assistance in

the drafting of specifications for textile purchases and testing of the

deliveries. The latter work was instrumental in the rejection of

many deliveries which did not comply with specifications. The work

also facilitated the economic purchase of textile supplies. Much cotton bunting and flags are now being used instead of wool, as the

Bureau has found that the cheaper cotton material, in many instances, can be economically employed.

The Bureau has assisted manufacturers of special textile apparatus

in suggesting improvements on their present machines and desirable

new devices needed by the textile industry. It has also constructed

machines for the accurate determination of length of textile yarns

and the " crimp " of yarns that have been woven into a fabric.

Considerable assistance was given the Customs Service in the

proper appraisement of duties upon textile yarns.

Several months of work were devoted in scouring raw wool fleeces

for the Agricultural Department. The results of the investigation

were valuable to that office in their sheep-breeding experiments.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 135

Special information was given in regard to linen produced from

domestic flax.

Publications on Textile Subjects.

The Bureau has recently published a revised edition of Circular

No. 41, on " Testing and Properties of Textile Materials." The previ- ous edition of the circular was issued two years ago. It deals in a general way with textile analyses, with particular attention given to

methods of test; atmospheric conditions under which certain tests should be performed ; precautions to be exercised ; results of special

tests; adulterated textile materials; rates of charges, etc. Nearly

2,000 copies of the previous issue have been furnished on request to

interested parties, and it has been especially in demand during the

past year.

Textile schools, manufacturers, buyex's and sellers, mill workers,

etc., use this circular as a guide in their testing, and it serves in a large way to educate the textile trade along lines of more scientific

manufacturing, buying, and selling. This is becoming more and

more important for the reason that the large consumers buy upon

definite specifications and test all deliveries.

An investigation has been made upon certain characteristics of

common cotton yarns with special reference to tensile strength and

yarn number under different atmospheric conditions. The results

of the investigation have been printed and distributed to the textile

trade as Technologic Paper No. 19, "The Physical Properties of

Cotton Yarns."

Technologic Paper No. 57, entitled " Difference Between Weight

of Raw and Clean Wools," is now ready for distribution. The paper

deals with the yield of clean wool obtained after scouring. Tests

were made upon 49 fleeces of typical Australian and New Zealand

wools commonly imported into this country. The investigation was

made to ascertain the shrinkage variation in two samplings of the

same fleece and the difference in shrinkage between two fleeces of the

same breed of sheep. The results are given in detail and should be

of value to wool manufacturers and wool buyers.

The Bureau will forward these papers upon request and will also

furnish any other textile information that can be supplied.

Investigation of Paper for Permanent Records.

The statement is often made that for durability no paper made

under modex'n methods can compare with that made 100 or 200 years

ago. Undoubtedly many of the modern papers would have a relatively short life as compared with those papers made before the

introduction of some of the Avood pulps and before the use of chemical bleaching became necessary to satisfy the demand of the public

for bright white papers.

The question of the xipkeep of modern libraries is a serious one,

and at the request of a number of libraries this Bureau is investigating the conditions that cause paper to turn yellow and become brittle.

At the present time there are no reliable tests which can furnish

information in regard to the possible life of a paper in actual use. The object of this investigation is to develop such tests, in order

that permanent papers may be used when needed.
136 EEPOKT OF DIRECTOR OF BUREAU OF STANDARDS,

Influence of Atmospheric Moisture on Printing Paper.

Paper used for general printing and for printing by means of

the various color processes, such as lithography, etc., are subject to

expansion and contraction, due to changes in the amount of moisture

in the air. This change in size, if excessive, may cause a serious loss

to the printer, due to the spoiling of partly finished work. At the

suggestion of a number of lithographers and printers this question

has been taken up for the purpose of devising means to overcome

this difficulty. There appears to be a point above which a change

in the relative humidity (per cent moisture content of the air) will cause a greater change in the dimensions of a sheet of paper than is found to be the case for similar changes in relative humidity below

that point. Certain manufacturing conditions tend to increase the

effect of atmospheric moisture on the change in size of paper.

It is proposed to study the manufacturing conditions involved, in

order to determine means whereby the effects caused by change of

humidity may be overcome. Comparison of Various Types of 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 when used for a particular purpose. With this in view,

the Bureau is noAv carrying out a series of tests on a number of types

of testing devices commonly used in the paper industry.

Utilization of Old Papers for Remanufacture into Paper,

One of the most available materials has been very largely over- looked in the demand for a new raw material for the manufacture of

paper. Only a small percentage of all paper made is collected for

remanufacture. The methods for the recovery of this possible raw

material are very wasteful, adding to the cost of the finished product.

It is proposed to study the present methods employed in the

recovery of old papers, with the object of determining the most suitable method.

Casein and its Application to the Paper Industry..

Casein is an important substance found in milks. It may be used

as an adhesive and as such is very largely used in the paper industry

to bind a thin film of clay or other material to the surface of the

paper. Paper so treated is known as coated paper, and is used in the

i-eproduction of photographs Avhere detail is essential and for printing by means of the various color processes, such as lithography, etc. Casein is produced from either skim milk or from buttermilk.

Commercial skim milk caseins are superior to buttermilk caseins,

due to the fact that they contain less insoluble material, greater

adhesive properties, and their use requires a less complicated method.

The best caseins are imported, and for this reason any investigation

tending to improve the domestic product will help to make an American industry less dependent on foreign made goods.

This casein investigation was undertaken at the request of the

Dairy Division, Bureau of Animal Industry. Department of Agriculture, and is a cooperative investigation. The Dairy Division has
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 137

installed the necessary apparatus for the manufacture of casein, and

the Bureau of Standards has undertaken the study of its application

to the paper. Most of the necessary machinery for coating paper

has been installed in the paper laboratory, and much of the preliminary work has already been done.

The particular purpose of the investigation is to establish the most

suitable methods for the production of skim milk and buttermilk

caseins, in order to overcome the great variation in quality found in

commercial lots. Attention will be given to methods of testing the

finished product and also the best methods for its use in the paper

industry.

Paper Testing.

During the past year the Bureau has tested the following samples

of paper : For the Government Printing Office and the Government

departments, 3,909 samples; for public and private interests, 157

samples ; total number of samples tested, 4,066. The large amount of

routine testing is an increase of 36.6 per cent over that done last

year and has very seriously handicapped the paper laboratory in

carrying out the investigations that have been demanded.

Information Furnished on Paper.

This section has been called upon by the several departments to

render special service in connection with the preparation of their

paper specifications, and assistance to departmental committees on

awards of contracts of this kind has been given to the congressional

Joint Commmittee on Printing, General Supply Committee, Post

Office Department Supply Committee, Committee on Awards for

Government Envelopes, Committee on United States Currency

Paper Awards, and a number of other committees.

The range of inquiries has covered not anlj the methods and

processes used in the pulp and paper industry and the testing of

jDapers but also many inquiries from allied industries. In a number of cases manufacturers have submitted samples of imported

papers, with the request that a report be made as to how such papers

could be duplicated. Special attention is always given to an inquiry

Avherein assistance may be rendered to an American industry.

The following is a list of a few of the inquiries received and give

an illustration of the range of subjects covered by means of letters

and reports

:

Report to State of Connecticut as to a suitable paper for their

court publications for permanent use. Reports on the possibility of using certain waste grasses for paper

making, it being shown that none of the common grasses are suitable, due to low yield of material, and the cost of manufacture.

Such material can only be used when other products of value besides

paper pulp are secured.

Requests for standard paper samples and specifications and lists

of testing devices and the method of operating the same. Request for samples of various paper-making fibers and pulps and

lists of manufacturers of various pulps and papers.

Suitability of various sizing materials.
138 EEPOET OF DIEECTOK OF BUEEAU OF STANDAEDS.

Suitability of waste cotton lint from cotton seed for manufacture

into paper pulp and guncotton.

The manufacture of vegetable parchment paper and reason why

the imported article is of superior quality to that of domestic manufacture.

Details as to the manufacture and use of the following papers:

Cigarette paper; dialyzing paper; chemical filter paper; photographic paper ; lining paper for electric dry batteries ; decalcomania

paper, etc.; stereotype matrix paper; lithograph paper; offset

paper, etc. The Bureau has been visited by a great many representatives of

the paper trade and has succeeded in establishing cordial relations

that will greatly enhance its cooperative work in the paper industry.

Investigation of Lubricating Oils.

As a result of trouble that has been experienced from the emulsification of engine oils in service, the Post Office Department has re- quested this Bureau to investigate the subject with the view of developing an adequate test for emulsibility. This investigation is well

under way, and the apparatiis that has been designed for carrying out

the work is giving very satisfactory results. A test for emulsibility

has been developed, and it has proved of so much value as an aid in

selecting the most suitable oil from samples submitted by prospective

contractors that it has been added to the list of routine tests to which

oils received from Government departments are submitted. In its

present form the test does not apply to steam-engine cylinder oils.

This test has been communicated to the American Society for Testing

Materials for the information of the committee on standard tests for

lubricants.

The conversion tables for intercomparison of different measures of

viscosity, which were mentioned in the last annual report, have been

presented to the American Society for Testing Materials, and will be

published in their proceedings as the work of this Bureau.

A publication is in course of preparation in which the theory of

viscous flow, upon which the action of viscosimeters depends, will be

considered in detail.

Investigation in Connection with Government Power Plants as to

Quality of Lubricating Oils.

During the past year the Bureau has employed an oil engineer

whose duties are to investigate all complaints of poor service of

oils delivered under Governmental contracts in Washington, to ascer- tain the reasons for unsatisfactory service, and to suggest remedial

measures. Numerous visits have been made to Government power

plants upon request, and in this Avay the Bureau has been able to

render valuable assistance of a distinctly practical nature.

A large number of oils have been tested, and the General Supply

Committee has been advised in regard to revising the forms of

contract for the purchase of lubricating oils for Government departments. Specific recommendations have been made, in cooperation with the chemical department, in regard to the comparative value

of oils submitted by contractors.
BEPOET OF DIKECTOB OF BUREAU OF STANDAEDS. 139

Properties of Rubber.

An investigation of the physical properties of rubber, with special

attention to the influence of temperature on these properties, has

shown satisfactory progress during the past year. The results of this

work appear in the third edition of Circular No. 38, " The Testing of

Mechanical Rubber Goods." Practically all of the testing machines

and apparatus used in this work have been developed at the Bureau.

The Bureau's equipment, which includes a mixing and vulcanizing

plant and a testing room with automatic temperature regulation,

offers exceptional facilities for research work. A rubber-tubing machine has been installed and is now being used for the production of

experimental tubing of various compositions. The object is to develop specifications for laboratory tubing which will insure more

satisfactory service than has been obtained in the past. During the

past year 34 rubber compounds have been made. About one-half of

these have been made into tubing which is being given a service test under A'arying conditions in the different laboratories of the Bureau.

A number of samples of special composition have been prepared and

are being used in checking different methods of chemical analysis.

The Bureau has cooperated with manufacturers and technical

societies in developing specifications for and methods of testing

rubber.

The special apparatus and testing machines designed at the Bureau

have been of distinct benefit to the rubber industry and to large

purchasers of rubber goods.

Investigation of Rubber Hose.

Specifications for rubber hose often require that the tube or lining

be made from calendered sheet. As distinguished from handmade

tubes of this kind, tubes are sometimes made by machinery, the

process being known as " squirting."

During the past year the Bureau has conducted experiments with

the view of developing a test that may be depended upon to identify

tubing as " calendered " or " squirted." The investigation has not

been completed, but from the results thus far obtained it appears that

the elasticity of rubber that has passed through a tubing machine

is practically the same in all directions, whereas it is generally known

that calendered sheet is more elastic in the transverse than in the

longitudinal direction. It is thought that a test for elasticity will

prove to be the most satisfactory method of distinguishing between

handmade and machine-made tubes in cases where tubes can not be

identified by inspection.

Kapok Fiber for Life Preservers.

At the request of the Steamboat-Inspection Service, this Bureau

has investigated the value of kapok fiber as a buoyant material for

life preservers, and a report based upon the results of chemical,

microscopical, and physical tests has been made.

It was found that the buoyant qualities of kapok fiber are not the

same for all products of similar trees, and since the difference is

purely physical it was recommended that the final valuation of kapok

should be on a physical basis. The best test of a life preserver is
140 KEPOKT OF DIKECTOK OF BUREAU OF STANDARDS.

a buoyancy test, extending over a definite time, during which time

the preserver should be totally submerged at intervals.

Efficiency o£ Hack-Saw Blades.

Very little progress was made during the past year in the investigation to determine the relative efficiency of hack-saw blades, taken

up at the request of the General Supply Committee. The data thus

far obtained show that the specifications in general use can not be

relied upon to secure blades of good wearing quality and high

efficiency. The Bureau's work has shown that m order to compare

the results obtained in different laboratories it is not only necessary

that the metal used for testing the blades be the same, but that in

each case the blades be tested under the same conditions as regards

cutting speed, pressure on blade, and length of stroke. The work of

this investigation will be continued and pushed as rapidly as circumstances will permit.

Investigation and Tests of Shot Lines for the United States Coast

Guard.

Tests of unusual importance have been made in connection with the

purchase of flax shot lines for the Coast Guard. The service re- quired of shot lines is of such a nature that it is necessary to exercise

the greatest care in selecting the material used in their manufacture

and to subject the lines to careful inspection and test. During the

past year 160 samples (representing 51,300 yards) of shot lines have

been tested, one-half of which was rejected for failure to meet the

specified requirements of tensile strength.

Test of Fire Hose for Use in the District of Columbia.

At the request of the District Commissioners, the Bureau has on

several occasions during the past year tested 50-foot lengths of fire

hose submitted by various manufacturers under competitive bid for

acceptance by the District of Columbia Fire Department.

These tests have resulted in a saving of about 50 per cent in the

cost of hose without sacrificing anything in quality or efficiency.

Tests of Miscellaneous Materials.

]\Iiscellaneous tests which were made principally for Government

departments included 158 samples of rubber hose, 115 samples of

packing (rubber, asbestos, etc.), 209 samples of rubber-covered wire,

35 samples of rubber bands, 246 samples of rope, 94 samples of leather

belting, 37 samples of hack-saw blades, and smaller numbers of

various other materials, amoimting to 1,057 samples in all.

III. OFFICE, AND ENGINEERING AND CONSTRUCTION.

1. OFFICE.

Publications.

During the fiscal year just ended the Bureau issued 137 publications, of which 46 were new and the I'emainder revised editions and

reprints. The new publications included five numbers of the Bulletin of the Bureau of Standards, which completes the eleventh volume

of the scientific papers. There were also issued 25 scientific papers,

10 new technologic papers, 8 new circulars, and 3 miscellaneous publications.
REPOBT OF DIRECTOR OF BUREAU OF STANDARDS. 141

The following new circulars were issued during the year : " Units

of weight and measure, definitions and tables of equivalents," " Standard methods of gas testing," " Safety rules to be observed in

the operation and maintenance of electrical equipment and lines," " National standard hose couplings and fittings for public fire service," " Measurement of time and tests of timepieces," " Regulation

of electrotyping solutions," " Composition, properties, and testing of

printing inks," and " Proposed national electrical safety code."

The following scientific papers were issued : " Testing of potentiometers," " Emissivity of metals and oxides—I, Nickel oxide (NiO)

in the range 600° to 1,300° C," "Adjustments of the Thomson bridge

in the measurement of very low resistances," " Quantitative experiments in radiotelegraphic transmission," " Measurements on standards of radiation in absolute value," " Experimental study of the

Koepsel permeameter," " Various modifications of bismuth-silver

thermopiles having a continuous absorbing surface," " Combustion

calorimeter and heats of combustion of cane sugar, benzoic acid, and

naphthalene," " SiDecific heat of copper in the interval 0° to 50° C.

with a note on vacuum-jacketed calorimeters," "Equilibrium in the

system : lead acetate, lead oxide, and water at 25°," " Watthour meter

method of testing instrument transformers," " Insulating properties

of solid dielectrics," " Direct-reading instrument for measuring the

logarithmic decrement and wave length of electromagnetic waves,"

" Electrical resistance and critical ranges of pure iron," " Absorption,

reflection, and dispersion constants of quartz," " Characteristic equations of tungsten filament lamps and their application in heterochromatic photometry," " Vibration electrometer," " Studies on the

silver voltameter," " Wheatstone bridge for resistance thermometry,"

" Emissivity of metals and oxides—II, Measurements with the micropyrometer," " Emissivity of metals and oxides—III, Total emissivity

of platinum and the relation between total emissivity and resistivity," " Comparison of stellar radiometers and radiometric measurements

on 110 stars," " Temperature coefficient of magnetic permeability

within the working range," " Methods of measuring the inductances

of low-resistance standards," and " Emissivity of metals and oxides

IV, Iron oxide."

The following technologic papers were issued : " Industrial gas

calorimetry," " Iodine number of linseed and petroleum oils," " Observations on finishing temperatures and properties of rails," "Analysis of printing inks," " Veritas firing rings," " Lead acetate test for

hydrogen sulphide in gas," " Standardization of No. 200 cement

sieves, " Hydration of portland cement," " Study of the Atterberg

plasticity method," and " Study of some recent methods for the determination of total sulphur in rubber."

The following miscellaneous publications were issued : "Annual

report of the Director for the fiscal year ended June 30. 1914,"

" Ninth annual conference on the weights and measures of the United

States," and " Decennial index to the Bulletin of the Bureau of

Standards."

Technical Library.

The Library contains 12,800 accessioned volumes, almost all of a

scientific and technical character, being an increase of 1,125 for the

fiscal year; and 362 periodicals are currently received, 211 in English

and 151 in other languages.
142 EEPOET OF DIRECTOK OF BUREAU OF STANDARDS.

Personnel.

During the year the Bureau staff comprised 233 statutoryappointees, and about 150 engaged in researches and investigations

specially authorized by Congress. The statutory positions included

145 scientific positions, 32 office assistants, 34 engaged in the operation of the plant, and 22 in the construction. There were 323 personnel changes during the year. These included fi5 separations from

the Bureau, of which 34 were resignations.

Correspondence.

The Bureau's correspondence is mainly technical and scientific in

chai'acter and requires the attention of experts and special care in

the preparation of repiiss. The problem of indexes and files is

necessarily complex in view of the wide range of technical subjects

covered by the Bureau's functions. The number of letters handled

by the file room during the fiscal year was 65,000, an increase of about

20 per cent compared with the previous 3^ear. In view of lack of

space and help the system of indexes and files was reduced to a minimum several years ago. Experience has shown that undue

simplicity as recommended by some filing experts may easily reduce

the efficiency in view of Government requirements. It is felt that the

growth of the correspondence requires that the system be revised

and a more complete cross-reference and charging system be installed. This is now under consideration and will be arranged as soon as possible.

Storeroom.

The pui'chase and distribution of equipment and supplier is handled through the storeroom. This includes system for orders,

inventory, charging out, and stock catalogue and maintenance of

standard supplies. The inventory record covers more than 60,000

pieces of equipment, largely scientific ajoparatus of the most varied

kinds. It has become necessary that a high-grade clerk be provided

as a property clerk.

Appropriation Statements.

The following statement shows the amount and object of each

appropriation provided for the Bureau for the fiscal year 1915, 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, 1915

Appropriation. Total appropriation. Disburse- ment. LiabUitj-. Balance.

Salaries Equipment

Repairs and alterations General e.xpenses Groxmds

Testing structural materials Testing machines High potentials

Refrigeration constants Testing raih-oad scales Fire-rcsisting properties

Testing miscellaneous materials. Railway materials Public utility standards Chemical laboratory

S293,

"2 57,

2, 27,

G, 100,

30,

15, 15. 40,

25,

20,

15, 25,

25,

500. 00 311.33

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

S2G6,412.79

38,184.85

1,524.02 21,584.35 5,001.67

85,940. 45 28,313.20

13,229.81

13,990.45

17,()29. 54 15,008.85

18,704.01

10,442.95

16,528. 01 2,375.00

Total. 695,811.33

$12,020.37

19,091.96

474. 50 5,320.39

997. 07 13,970.47

1,647.45 1,766.75

995. 03 22,370. 46 9,308.51

1,217.90 4,548.49 8,317.16

3,532.30

555,536.55 105,578.87

$15,066.84 34.52

1.48 95.26

1.26 89.08 39.35

3.44

8.52

22.64

77. 43 8.56

154.83 19,092.70

34,695.91

a Includes reimbursement of $7,311.33.
BEPOET OF DIKECTOE OF BUEEAU OF STANDAEDS. 143

The following statement shows the condition of the appropriations

for the two preceding fiscal years at the close of business June 30,

1915

:

FISCAL YEAR 1913.

Appropriation. Total appropriation. Disburse- ment.

Liability. Balance.

Salaries $241,312.66

.50,000.00 2,000.00

25, 000. 00

3,000.00

77,342.50 30,000.00

10.000.00

15,000.00 85,000.00 5,000.00

.$220,682.95 49,054.36

1,980. 80 24,544.05

2,986.81 77,045.29

29,841.13 9,921.03

14,915.58 68,034.00

4,996.98

$14,629. 71

326. 44 19.20 281.77

13.19

249. 22

158. 87 74.47 39.32

16,966.00 3.02

Equipment $619. 20 Kepairs and alterations General expenses Grounds

174. 18

Testing structural materials Testing machines

47.99

Investigating effects of electric currents Kefrigeration constants Additional land4.50

45.10 Tank

Total 543,655.16 510,002.98 890.97 32,761.21

FISCAL YEAR 1914.

Salaries $290, 940. 00

6 59,075. 00

2,000.00

27,000. 00

3,000.00

75, 000. 00

30,000. 00

15,000. 00

16,000. 00

25,000. 00

25,000. 00

25,000. 00

45,000. 00

$270, 123. 88

58,417. 49 2,000.00

25,365.14

2,997.53

74,609. 04 29,924.67

14, 963. 71

14,601. 61 22,315.00

23,324.49

24,960. 66

44,536. 22

$20, 816. 12 Equipment $540. 18 117.33 Repairs and alterations General expenses Grounds

467. 13 1, 167. 73

2. 47

254. 07

32. 67

32. 19 49.91

Testing structural materials Testing machines

High potentials

136. 89 42.66 4.10

348. 48

2, 684. 94

856. 04 22.30 423.78

Refrigeration constants Testing railroad scales Fire-resisting properties

Equipment, electrical laboratory

Workshop and storehouse

Total

819. 47 17.04 40.00

637,015.00 G08, 139. 50 5, 526. 50 23,349.00

a Includes reimbursement of $2,342.50.

6 Includes reimbursement of $9,075.

Statement of Tests.

The work of the Bureau involves, among other things, a large

amount of testing of standards, measuring instruments, and materials. It involves primarily the investigation of the scientific principles underlying the tests, the study 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 1915 the Bureau made 116,204 tests and inspected 1,861,439 incandescent lamps at various factories for other

departments of the Government. Of the total tests, 105,992 were for

the Government and 10,212 for the public. The testing was distributed as follows, according to nature of tests: Length measures,

949; mass, 7,529; capacity, 2,230; temperature, 15,734; hydrometry,

2,224; miscellaneous, 153; optical, 1,500; time, 28; electrical, 1,223;

photometry, 3,506; chemical, 11,471; engineering (miscellaneous),

878; engineering (instruments), 367; structural materials, 60,989;

paper and textiles, 7,359; metallurgical, 64. The estimated fees

amount to $154,733.59, of which $14,438.43 was 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.
144 EEPOET OF DIEECTOR OF BUEEAU OP STANDARDS.

Number and VAi-ttE or Tests Completed, Fiscal Yeae Ended June 30, 1915.

Nature of test.

For Government. For public. Total.

Number. V3,lllG. N'llTnbpT" Vnlnp "WllTTlVlPt* LLILI UOl . V aiue.

000 313 !5o30. 5U 949 SI, 85o. 80

6, 252 3, ^3. 45 1 , 277 657. 65 7,529 3,951. 10

1, 803 530. 15 427 331. 35 2, 230 861. 50 Hydrometry

1,443 1,709.70 57 92. 50 1,500 1, 802. 20

2,06G 2, 081. 50 158 273.00 2,224 2, 354. 50 Miscellaneous 144 190. 40 9 13.80 153 204. 20

28 120. 00 28 120. 00 Temperature 9,843 3,588. 39 5,891 2,979.04 15,734 6, 567. 43 Electrical 770 2, 675. 00 453 2,988.00 1,223 5,663.00 Photometry o 3,330 11,483.55 176 629. 30 3,506 12,112.85

10, 856 66, 878. 10 615 3,164. 40 11,471 70,042.50 Physical and mechanical tests: Engineering, miscellaneous 878 2, 520. 50 878 2, 520. 50 Engineering instruments 314 1,589.00 53 229. 50 367 1,818.50 Structural materials c 60,634 32,531.67 355 1,374.00 60,989 33,905. 67 Paper and textiles 6,982 9,741.45 377 598. 51 7,359 10,339.96

41 457. 00 23 156.88 64 613. 88

Total 105,992 140, 295. 16 10,212 14,438. 43 116,204 154, 733. 59

a In addition, the Bureau inspected 1,801,439 incandescent lamps at various factories for other departments

of the Government, the fees for which would amount to 85,546.47 additional.

6 Of these tests, 5,513, amounting to §39,941.80, were chemical tests made on structural materials.

c These figures include the inspection of approximately 53,708 samples of Portland cement.

2. ENGINEERING AND CONSTRUCTION.

Mechanical Plant.

The completion of the chemical laboratory authorized by Congress

will necessitate enlargement and remodeling of the power and heating

system by the construction of an addition to the present building, or

a smaller one detached from it, to provide for additional boiler and

power-plant space. The Bureau has also outgTown the capacity of its

refrigerating plant originally installed at the establishment of the

Bureau. The necessity for the control of temperature and humidity

in many tests and experimental problems requires the installation of

a larger plant at the earliest possible moment. The general condition of the power plant is far too inadequate.

Construction Facilities.

The care of the mechanical plant, of the buildings, and especially

the construction of special apparatus of all kinds, necessitates a corps of mechanics skilled in the various kinds of construction.

Every investigation requires the construction of more or less special

apparatus involving mechanics skilled in the construction of all kinds

of precision instruments. These services include plumbing and steam

fitting, electrical wiring, woodworking, instrument making, glass

blowing, and glass grinding—all are involved in both investigational

and testing work. In fact the Bureau's efficiency depends very

largely upon having services of this sort available.

Care of Buildings and Grounds.

The care of the buildings of the Bureau has been inadequate for

several years. This has been in part remedied by a system of con- tinuous supervision of the janitor service. It is hoped that the janitor service may be increased during the coming year.
EEPOET OP DIEECTOE OF BUEEAU OF STANDAEDS. 145

During the year some grading has been completed south of the

main laboratory and around the east laboratory. Pierce Mill Road

has been temporarily improved by eliminating bad curves and ex- treme grades. This has resulted in improved truck service. The care

of the grounds has become of sufficient importance to warrant the

continuous employment of a foreman.

IV. RECOMMENDATIONS.

Buildings.

Attention is again called to the necessity of properly housing the

structural materials work, especially the branch of the work at Pittsburgh, and which is temporarily located in buildings of the War

Department at the Arsenal grounds. These buildings are entirely

unsuited for the purpose either as to location or character, and the

Bureau has considered it unwise to expend any funds on their

preparation as laboratories other than the barest necessities. Furthermore, the War Department has repeatedly asked for the vacation of

the building.

Every effort is being made by the Bureau to place its structural

work on a basis commensurate with its importance. Considerable

heavy equipment has been accumulated both at Pittsburgh and Washington, and more will be needed. Good work is being carried on at

both places but the large testing machines, furnaces, and other heavy

equipment should be brought together in a building designed for the

purpose and sufficiently large to accommodate all heavy equipment

of this kind. It is uneconomical and inadvisable to proceed with the

installation of permanent heavy equipment in temporary quarters.

Transverse Testing Machine.

Attention is again called to the necessity of adding to the Bureau's

equipment a large transverse testing machine capable of testing the

transverse strength of full-sized steel girders used in bridges and

buildings; also brick, stone, and concrete arches, floor constructions,

etc.Since transmitting the original estimate for this machine, much

additional evidence has been secured, all indicating the great need

on the part of engineers for data that can only be obtained by a large

machine of this character. It is therefore recommended that a suffi- cient sum be again included in the estimates to enable the Bureau of

Standards to begin its design and construction.

Radio Laboratory.

Radio communication has recently become of extreme importance

both in Government work and to the public. This method of communication is still largely in the experimental stages. Future progress and improvement in radio communication will be in direct proportion to the progress that is made in the knowledge of the underlying principles involved. Several departments of the Government

are deeply interested in maintaining this method of communication

on the best possible basis. It would not only be more economical, but

productive of much more efficient work to concentrate the laboratory

10739°—15 10
146 REPORT OF DIRECTOR OF BUREAU OF STANDARDS.

work of the Government at one place in a small laboratory especially

designed for it. It has been agreed by all of the departments con- cerned, namely, War, Navy, Treasury, Post Office, Agriculture, and

Commerce, that the location of the laboratory at the Bureau of

Standards would prove of gi'eat benefit both as to the economical performance of the work and by its close proximity to the scientific work

of the Bureau, especially that of the electrical division. An item of

$50,000 for the construction of a suitable radio laboratory was included in the estimate for the current year, but was not appropriated

for. It is recommended that it be again submitted in the estimate for

the next fiscal yeac

Salaries and Additional Assistance.

Moderate increases are submitted for the heads of divisions. These

positions involve the responsible administration of the several lines

of the Bureau's technical activities. The compensation is not adequate either in view of the duties involved, the order of ability re- quired, or in comparison with similar grades elsewhere. These

include the chief physicist, chief chemist, the physicists, secretary,

and chief mechanician.

Several increases are also submitted for the skilled workers in the

operative and construction staff, namely, the glassworker, the glass

blower, and the skilled woodworker. An increase in these salaries is desirable, as their rate of pay is below the average standard for such

services elsewhere. An estimate is also submitted for an increase

for the assistant engineer, who is in direct charge of the engineering

plant and the systems of heat, light, and ventilation connected therewith.

During the past two years the Bureau's work has grown far more

rapidly than its resources. This is especially true in consultation

and testing work for the Government. In several sections of the

Bureau it has been necessary to suspend all investigations in order

to care for the testing of materials purchased on Government contracts. This would not be so serious if suitable specifications and

methods of testing were in existence for the wide range of materials

to be tested ; but it can truly be said that such is the case in only a very limited number of materials. It is felt that this situation can be

remedied to a large extent by a reasonable increase in the minor

assistants, such as apprentices, aids, and assistants up to and including the grade of $1,400. A few of these men in each section could

almost double the Bureau's output of testing, and, what is still more

important, allow more time on the part of aclvanced men for the improvement of methods and specifications.

Clerical Services.

The clerical assistance of the Bureau has been entirely inadequate

for the past four years. So critical has this become during the past

year that it is a serious question as to whether the Bureau is not very

materially reducing the efficiency of all branches of its work by the

lack of anything like adequate clerical assistance. This is especially

true in the case of property records, accounting, files, and corre- spondence.
REPORT OF DIRECTOR OF BUREAU OF STANDARDS. 147

Skilled and Unskilled Labor,

The situation of the Bureau is such that it is impractical to secure economical contracts for small jobs of construction. These are continually arising in all kinds of experimental work. Their nature is

such that they require the supervision of the experts of the Bureau.

It is no uncommon matter when soliciting bids for this class of work

to receive them of three or four times the amount necessary. This

is due to the distance of the Bureau from the city, the necessity for

the supervision of the work on the part of the contractor, and his

hesitation to undertake work of a character unfamiliar to him. It

is therefore recommended that the Bureau staff of this class of skilled

and unskilled laborers be increased.

Technical Investigations.

Items are included among the estimates for the fiscal year 1917 to cover several of the more urgent technical and scientific investigations which should be undertaken by the Bureau. There is the

utmost need in the industries for accurate data concerning materials

and energy, their measurement and properties. These subjects are a part of the authorized functions of the Bureau, but they have not yet

been adequately provided for. These appropriations will enable the

Bureau to render a direct service to the industries concerned. The

investigations include color standards, clay products, standard materials, physical constants, standardization of mechanical appliances,

and textiles, paper, leather, and rubber.

The economic value of these investigations will unquestionably

repay many times the original outlay. That they are urgently

demanded by the industries is evidenced by the continual receipt of

letters calling for the data which these investigations alone can supply. Furthermore, the results will enable the Bureau to put the

work of standardizing the measurements and quality of these materials upon a basis not heretofore practicable.

Promotion of Export Trade.

It is intended to use this appropriation to meet a new and urgent

demand which has recently arisen from several industries for the cer- tification of American products for export trade. In the tradepromotion work of this department it is found that a governmental

certificate of the actual quality of export products is becoming more

and more necessary. In many foreigTi countries the government

testing laboratories are furnishing such certifications, and this gives

the foreig-n manufacturer a distinct advantage over the manufacturer

in this country, especially in cases where a quality certification by a recognized governmental agency is required by the specifications for

the materials to be exported. This appropriation is designed to place

the American exporter, so far as possible, on an equality in this

respect with his foreign competitors.

The appropriation provides for the charge of an adequate fee for

each certification to be made by the Bureau of Standards to reimburse

for the expense incurred.
148 BEPOET OF DIRECTOR OF BUREAU OF STANDARDS.

The appropriation suggested will prove a great help to manufac

turers and producers in this country who are desirous of selling thei

goods to foreign countries.

Respectfully,

S. W. Stratton, Director.

To Hon. William C. Redfield,

Secretary of Oommerce.

o