AlN N U A L, REPORT

OF THE

DIRECTOR

OF THE

NATIONAL BUREAU OF STANDARDS

FOR THE

FISCAL YEAR ENDED JUNE 30, 1902.

WASHINGTON

CTOVIRNMSNT PRINTING OFFICE

1903
I
AJN~1>\TJ.A I , REPORT

OF THE

DIRECTOR

OF THE

NATIONAL BUREAU OF STANDARDS

FORI THE

FISCAL TEAR ENDED JUNE 30, 1902.

WASHINGTON

GOVERNMENT PRINTING OFFICE

11)03
Treasury Department,

Document No. 2316,

National Bureau of Standards.
ANNUAL REPORT OF THE DIRECTOR OF THE NATIONAL

BUREAU OF STANDARDS.

Treasury Department,

National Bureau of Standards,

Washington, D. C, February 19, 1903.

Sir: I have the honor to submit the following- report of the operations

of this Bureau for the fiscal year ended June 30, 1902:

ESTABLISHMENT AND PURPOSE.

By an act of Congress approved March 3, 1901, the Office of Standard

Weights and Measures of the Treasury Department was, on July 1, 1901,

superseded by the National Bureau of Standards, the functions of which

may be briefly stated as follows: the custody of the standards; the

comparison of the standards used in scientific investigations, engineering,

manufacturing, commerce, and educational institutions, with the standards

adopted or recognized by the Government; the construction, when necessary,

of standards, their multiples and subdivisions; the testing and calibration of

standard measuring apparatus; the solution of problems which arise in

connection with standards; the determination of physical constants and the

properties of materials. The Bureau will also furnish such information

concerning standards, methods of measurement, physical constants, and the

properties of materials as may be at its disposal, and is authorized to exercise

its functions for the Government of the United States, for State or municipal governments within the United States, for scientific societies,

educational institutions, firms, corporations, or individuals.

SELECTION OE SITE.

The act of Congress establishing the National Bureau of Standards

provided for the purchase of a site and the erection of suitable laboratories.

3
4 ANNUAL REPORT OF THE DIRECTOR OF

The site selected consists of about 7^- acres in the most desirable section of

the suburbs! of Washington, in a neighborhood particularly free from

mechanical and electrical disturbances, but sufficiently easy of access. The

fund available for the purchase of a site, while sufficient to secure the area

necessary for the buildings, was hardly sufficient to purchase the area

necessary toj insure freedom from disturbance when the neighborhood in

which the Bureau is situated becomes more completely settled. The

Government should secure as soon as possible the remaining portions of the

block in which the site is situated, bounded on the north by Shepherd

street, on the east by Connecticut avenue, on the south by Quincy street,

and on the west by Idaho avenue.

PLAN OF THE WORK.

After tht^ selection of a site, the problems confronting the Bureau were

the organization of the working force; the preparation of the plans of the

laboratories and their permanent equipment; the preliminary work in the

many lines of work in order that the apparatus might be designed and

constructed or purchased, and methods decided upon by the time the

buildings were ready for occupancy; the comparison and testing of such

standards and measuring instruments as could be undertaken in temporary

quarters and with the facilities at the disposal of the Bureau.

TEMPORARY QUARTERS.

During this year the quarters occupied by the Bureau consisted of eight

rooms in the third floor of the middle and south Butler buildings, which have

been used for offices and laboratory purposes, and eight rooms which were

formerly used by the office of Weights and Measures in the United States

Coast and Geodetic Survey building, which were retained for laboratory

purposes. It soon became evident that this amount of space was not sufficient

for even the most elementary work, and that the new laboratories would not

be ready for occupancy as soon as expected. Steps were therefore taken to

secure additional quarters. A large four-story residence building at 235 New

Jersey avenue SE. was secured, and became available for laboratory purposes

July 1, 1902. This building will provide space for the organization of
THE NATIONAL BUREAU OF STANDARDS. 5

several new lines of work and for the collection and testing of the apparatus

to be used in our own equipment and to be moved later to the new laboratories.

It will also provide space for an instrument shop, which is of the utmost

importance, since much of the apparatus to be used in the Bureau is special

in character and must be designed and built under the supervision of experts.

The ordinary testing of standards and instruments is necessarily attended by

the adjustment of weights and measures and other work of a mechanical

nature.

PERSONNEL.

The limited number of positions provided for by the act establishing

the Bureau was only sufficient to begin the solution of the problems enumerated above. The list is as follows, including the additional positions available July 1, 1902:

The Director.

Scientific Division.—One physicist, two assistant physicists, five laboratory assistants, and two laborers.

Engineering Division.—One engineer, one assistant engineer, two

mechanicians, one skilled laborer, and one watchman.

Office Division.—Secretary, two clerks, one storekeeper, one messenger, and one laborer.

PLANS FOR THE NEW LABORATORIES AND THEIR EQUIPMENT.

The work for which the National Bureau of Standards was established

includes research and testing in the domain of physics, extending into the

field of chemistry on the one hand and of engineering on the other. The

union of research and testing in one institution is of supreme importance, the

investigations being, of course, primarily designed to carry the work of

standardization and testing to the highest possible efficiency. The Physikalisch-Teclmische Reichsanstalt of Germany is an illustrious example of

how much can be accomplished where research and testing are combined in

one institution. The laboratory requirements are, therefore, those of a research laboratory plus whatever special facilities may be needed for

commercial testing. In addition to the workers themselves, there is then

required (1) a suitable place in which to work, (2) an equipment of
6 ANNUAL REPORT OF THE DIRECTOR OF

apparatus, tools, and machines, and (3) facilities and appliances for

providing the proper conditions for experimental work. Two buildings

have been planned, one of which, the Mechanical Laboratory, is now

under construction, and the plans for the other are completed. The

latter, which is called the Physical Laboratory, will provide for that part of

the experimental work which ought to be kept free from mechanical and

magnetic disturbances, and to this end will contain scarcely any machinery.

It will also contain the offices for administration, the library, and a wellequipped chemical laboratory. The Mechanical Laboratory contains the

mechanical plant, instrument shop, and laboratories for the heavier kinds of

experimental work, where considerable power or large currents are required.

These two buildings are to be connected by a spacious tunnel, through

which air ducts, steam, gas, and water pipes, and electric circuits are

carried from the Mechanical to the Physical Laboratory. The facilities and

appliances for bringing an experiment under the proper conditions are more

difficult to secure than the apparatus itself. In general, laboratory rooms

should be well lighted and ventilated, and their temperature should be

under control. The windows should be double, in order that the space near

the window i (often the most valuable space in the laboratory) may be

warmer in cold weather and cooler in warm weather, and freer from drafts

of air than would be the case with single windows. It should be possible

quickly and conveniently to darken many if not all the rooms. The

temperature of the laboratory should be automatically controlled by

thermostats, so that any temperature (within certain limits) which may be

required by any particular experiment or investigation may be maintained

both day and night, if necessary, for any desired period. The humidity of

the air should be low, so that moisture developed in the room either by

respiration or evaporation may be absorbed by the air and carried away

instead of depositing on the walls and furniture of the room and apparatus.

These last considerations, the control of the temperature and humidity of

the air, are vital. Many kinds of work can ordinarily be done only in the

winter months, because summer temperatures and summer humidity can

not be controlled. This involves not only long delays, but often a large

amount of extra labor. This is perhaps most often the case in electrical
THE NATIONAL BUREAU OF STANDARDS. 7

work, but in many other instances it is equally important. Apparatus,

tools, and machines often suffer by rusting in summer, in spite of the fact

that the attendant means to be careful. Hence in a laboratory where

work is to be carried on during the entire year, and where a large quantity

of valuable apparatus and instruments of precision are in use, and where,

in addition, valuable apparatus is to be received from outside for testing,

the necessity of controlling the humidity as well as the temperature of the

room is evident.

The buildings will be heated by the double-duct system—hot air from

one duct is mixed with cooler tempered air from a second duct in such

proportions as to hold the temperature of the room constant, the proportions

of the hot and tempered air being regulated by a pair of dampers, the latter

being automatically controlled by means of a thermostat. Each room of

a building, therefore, has its own supply flue, regulating dampers, and

thermostat. The latter may be set at any desired temperature within the

range of the apparatus. If in hot weather the hot-air duct carries air

taken from out of doors, say at 90° F., and the tempered-air duct carries

artificially cooled air, say at 60°; a mixture of the two may give a room

temperature of 75°, when the temperature would otherwise be 80° or 85°.

The thermostat will adjust automatically the proportions of cooled and

uncooled air so as to hold this temperature constant, thus preventing the

usual gradual increase of temperature as the day progresses. By a

readjustment of the thermostat any other constant temperature can be

secured, provided it is within the range of the system.

The laboratory facilities will include gas, compressed air, vacuum, hot

and cold air, and ice, cold brine, liquid carbon dioxide, and liquid air will

be provided for the production of low temperatures. Gas and electric

furnaces will be available for high temperatures. The electrical equipment

will include the dynamos, motors, storage batteries, transformers, and other

apparatus necessary for the production of the range of current and voltage

required for experimental and testing purposes.

The Mechanical Laboratoiy is approximately 41 meters (135 feet) longby 16 meters (51 feet) wide and is three stories high. A large extension of

the first floor increases its area by nearly 50 per cent. This floor will include
8 ANNUAL REPORT OF THE DIRECTOR OF

a boiler room large enough to contain the boilers, pumps, tanks, and other

accessories necessary for the present equipment and a reasonable amount of

expansion, a large engine and dynamo room, a large room for the refrigerating

and liquid-air plants, a large storage-battery room, also rooms for the heating

and ventilating apparatus, gas plant, coal supply, and storage. The second

floor will include an instrument shop, woodworking shop, and several

laboratories for electrical work requiring heavy currents. The rooms of

the third flo<pr will be used for electrical work and other testing.

The Physical Laboratory is approximately 52 meters (172 feet) long,

17 meters (53 feet) wide, and four stories high, with an attic containing

considerable available storage space. The building will be of extra heavy

construction, will be well lighted, and the first two floors reserved entirely

for experimental purposes. A corridor will extend the entire length of the

first floor and the exterior of the building will be so designed that if in the

future additional buildings should be needed they may be placed one on

the east and the other on the west, and connected to it by an arcade opening

into the corridor of the first floor.

A base nent is excavated only under the central portion of the building

and under the corridor, the laboratory rooms at either end having concrete

floors, upon which piers may be built as they are found necessary. All of

the rooms of the first and second floors will be practically constant-temperature rooms, with automatic temperature control. They will have double

windows, piovided with light-tight shutters for darkening the rooms when

necessary. The laboratories of this building are provided with all of the

usual laboritory facilities; ample ducts and spaces are provided for placing

wires or piping that may be needed in the future.

This building will contain laboratories for testing and investigations in

the following subjects: weights and measures, including length, mass, and

capacity; electricity, including standards of resistance, electromotive force,

and induction. The space allotted to the subject of electricity will also

include laboratories for general research and investigations in connection

with electrical standards, measuring instruments, constants, and the electrical

properties of materials. The subject of thermometry will be amply provided

for and will include the testing of all kinds of mercurial thermometers and
THE NATIONAL BUREAU OF STANDARDS. 9

the instruments for measuring1 temperatures above and below the range of

mercurial thermometers as well as facilities for investigations in this field.

The third floor of the building will be devoted to the Library, Museum,

supply rooms, and administration. The fourth floor will be fitted up as a Chemical Laboratory.

In addition to the heating and ventilating system in this building, there

is a separate exhaust system connected to each laboratory, toilet room,

storage-battery room, hoods of the chemical laboratory, etc. These exhaust

flues will be provided with a fan sufficiently strong to secure a positive

draft for carrying off all noxious fumes or vapors that may be generated in

these rooms. Much attention has been given to the permanent laboratory

equipment, such as plumbing, working tables, cases, etc.

WEIGHTS AND MEASURES.

The work of the past year has involved the verification of a large

number of standards of length, mass, and capacity for the Government and

for chemists, engineers, State and city sealers, manufacturers, and merchants.

In addition to the work done for the public, considerable attention was

given to the improvements of comparers, balances, and other apparatus used

in the work of this character, the object being to design apparatus which

will permit of the work being done with the required accuracy and the

maximum speed. This of course applies only to the routine comparisons,

which have to be made in large quantities for nominal fees.

Verifications of the highest scientific accuracy will be always more or

less laborious and require more time, but even here both labor and time are

greatly reduced if the proper equipment is provided. The verification of

the weights and measures, including hydrometers, polariscopic apparatus,

and other appliances used in everyday transactions, is one of fundamental

importance to the Government and to the people at large. The rapid

development of our industries has resulted in new demands upon the

Government, to which it would not have been subjected formerly. There

is hardly a field in which competition does not exist, and in consequence the

Bureau is called upon to settle questions of standards that w ould scarcely

have arisen a few years ago. Another cause contributing to the increased

90378—03 2
10 ANNUAL REPORT OF THE DIRECTOR OF

demands alolig these lines is the necessity for greater accuracy. What

would have teen considered sufficiently accurate a few years ago will no

longer satisfy engineers, manufacturers, merchants, or the public.

Among the more urgent matters demanding attention are the following:

1. The verification and stamping of chemical glassware, such as flasks,

burettes, andj graduates. Large quantities of graduated glassware are used

by chemists, who are at present obliged either to test it themselves or purchase German ware, which has been examined and stamped by the

German bureau of weights and measures. This causes great inconvenience

to our chemises, and, moreover, makes it difficult for American manufacturers

to compete with German makers of high-grade measuring apparatus, whose

product bean ; an official stamp indicating the accurac}^ of its graduations.

Preliminary plans to meet the demands of chemists and manufacturers

have been prepared, and it is expected that by the end of the next fiscal

year the Buijeau will be in a position to test this ware in small quantities.

2. The design and construction of a model set of weights and measures

that shall be .adapted to the needs of State, county, and city sealers. The

sets of weights and measures furnished to the States in accordance with the

acts of 1836 and 1866, while doubtless good enough for the dates of the

design, do nor meet present requirements. The Bureau is continual^ called

upon by State and city authorities for information as to where suitable sets

may be procured, and the preparation of such a model set,

regulations for their use, are matters that are daily becoming

of standards

together with

more urgent.

3. The r resent chaotic condition of the question of hydrometers is also

one demanding immediate attention. Numerous hydrometers for special

purposes are in use, none of which are based upon an authoritative table of

isponding to the indications of the instrument. In consequence

much confusion exists among manufacturers and merchants, and even officers

of the Govern|nent, as to the meaning of the graduations of these instruments,

and the aid oi the Bureau is frequently invoked.

THERMOMETRY.

The work in thermometry lias hitherto been confined to the testing of

mercurial theijmometers within the range from about —20° C. (—4° F.) to
THE NATIONAL BUREAU OF STANDARDS. 11

about 50° C. (122° F.). Work within this narrow range no longer satisfies

the requirements of scientific work or the demands of technical processes.

Many of the processes of manufacturers are dependent for their successful

operation on an accurate knowledge of the temperature, such, for example,

as annealing, hardening, tempering, galvanizing, distillation, smelting, etc.,

temperatures of hot blast and furnace gases, of furnaces and ovens used in

the various industries, such as the manufacture of steel products, glass,

porcelains, and other ceramic materials, etc. In many operations comparatively slight variations of temperature produce wide differences in the

character of the resulting products. This has led to an increasing demand

for thermometers and pyrometers that will register high temperatures.

Manufacturers abroad have been quicker to realize the great importance of

an accurate knowledge of the temperature in many lines of work, although

these questions are now beginning to receive due attention in this country.

The lack of proper attention to this question is undoubtedly due to the

absence of suitable standards of temperature, for the indications of the

various pyrometers found on the market yield widely different results and

consequently lead to confusion and loss of confidence, and this in a great

measure not due to inferiority in construction of American instruments, but

is inevitable, as the manufacturers could not obtain uniform standards, so

that each maker was compelled to establish his own scale of temperature as

best he could with the facilities at hand. The result has been that American

manufacturers have been compelled to go abroad for reliable standards

which are certified by foreign testing bureaus.

To meet these requirements specifications have been drawn up and the

necessary apparatus purchased or constructed that will in the near future

enable the Bureau to undertake the testing of all kinds of temperaturemeasuring instruments up to about 1,500° C. (2,700° F.).

The liquefaction of air and other gases on a large scale has opened

up a new and important field of research on the properties of matter at

extremely low temperatures and occasioned a demand for thermometers

whose scale extends considerably below that of the mercury thermometer.

The Bureau is preparing to meet these requirements, and will very soon lie

able to certify such thermometers for temperatures as low as —190°

(-310° F.).
12 ANNUAL REPORT OF THE DIRECTOR OF

Many inquiries have been addressed to the Bureau by various

manufacturers with reference to the testing- of clinical thermometers, and

the necessary preliminary work is now well under way. Many thousands

of these thermometers are tested and certified each year by foreign testing'

bureaus, and -the high standard of requirements set by those bureaus has

done much toward improving the accuracy and reliability of thermometers

of this type.

ELECTRICAL STANDARDS.

A laboratory has been fitted up for the verification of standards of

resistance and electromotive force, in terms of which all electrical

measurement^ will be directly or indirectly expressed. A large number

of resistance standards, ranging from 0.0001 to 100,000 ohms, have been

secured and (suitable comparing apparatus has been acquired, so that the

Bureau is already equipped for the measurement of resistance standards

submitted for verification in terms of those belonging to the Bureau to the

highest orderj of accuracy.

The international unit of resistance, legalized by act of Congress in

the United States, was defined by the International Electrical Congress in

terms of the resistance of a column of mercury of specific dimensions at a

specified temperature, and it was assumed that the various governments

represented would take up without delay the construction of new mercurial

standards. While the use of secondary standards for ordinary purposes

suffices, it is most important that the Bureau should undertake the

construction of primary mercurial standards at the earliest possible

moment, not only to place the resistance measurements on a firmer basis,

but also to determine, in conjunction with the laboratories of other

governments) the accuracy with which such standards may be reproduced

from their definitions, and to construct a number of secondary mercurial

standards, a$ such standards after aging are not subject to as large

variations as wire standards.

Facilities are now provided for the verification of resistance boxes,

ratio coils, potentiometers, and other classes of apparatus, and facilities

are to be provided for the calibration of low-resistance standards of high

carrying capacity, for the determination of specific conductivity, and

insulation resistance.
THE NATIONAL BUREAU OF STANDARDS. 13

A considerable portion of the time during the past year was spent in

planning- the work to be undertaken and in the design of special apparatus.

During the past year a considerable number of resistance standards

have been verified for manufacturers, scientific institutions, and the

Government.

STANDARDS OF EEECTRO-MOTTVE FORCE.

Accurate measurements of electro-motive force are as fundamental as

the accurate measurement of resistance. A number of Clark standard

cells, legalized by Congress as the standard of electro-motive force in the

United States, have been constructed from chemically pure materials

obtained from a number of different sources, and also from the same

materials subjected to further purification. Although the agreement of the

individual cells with each other is within two parts in 10,000, a further

supply of materials for new cells has been purchased. This material will

be analyzed and subjected to further purification in order that the standards

of electro-motive force may meet every requirement.

The main source of the variation of the electro-motive force of the

Clark cell seems to be due to the differences in one of the ingredients used,

and investigations should be directed to ascertain under what conditions

this material can be obtained with uniform electro-motive properties.

When the unit of electro-motive force was defined by the International

Congress, the best determinations of the value of the Clark cell in terms of

that unit corresponded to the relation 1 volt — 1000/1434 electro-motive

force of the Clark standard cell at 15° C. Subsequent work lias indicated

that the volt thus defined is too small by almost one part in a thousand. A

different unit has therefore been adopted by Germany. Moreover, another

type of standard cell, the Weston, has been found to possess some advantages

over the Clark cell. A number of these cells have already been set up and,

in view of the possibility of its adoption as the official standard of reference,

others are to be constructed and compared with each other and with the

Clark standard cells.

Although the measurement of electric currents will be based upon

standards of resistance and electro-motive force, the Bureau should undertake

the redetermination of the electro-chemical equivalent of silver, upon which
14 ANNUAL REPORT OF THE DIRECTOR OF

the legal definition of the unit of current is based, since the value adopted

is not consistent with the definition of the two other fundamental electrical

units—the own and the volt.

THE VERIFICATION OF AMMETERS AND VOLTMETERS.

One of the temporary laboratories has been fitted up for the calibration

of voltmeters and ammeters, and while the range is at present limited to 150

volts and 50 amperes, apparatus will soon be installed for increasing these

ranges to 2,000 volts and 1,500 amperes. The necessary galvanometers,

resistance standards, resistance boxes, regulating rheostats, and other

accessory apparatus have been provided. A comparative study of the

different makes of American instruments will be made after the working

standards of the Bureau have been calibrated. Facilities will also be

provided forfthe measurement of ammeter shunts of high carrying capacity.

A number Of requests for work of this kind have already been made.

With facilities for the measurement of high voltages and heavy currents,

the Bureau Will also be prepared for the verification of direct current wattmeters and supply meters; and this work will be undertaken for the public

as soon as ail adequate force is provided.

It is desirable that a portable apparatus be designed which will permit

electric lightj and power companies so disposed to have their switch-boards

and other apparatus tested in place.

ALTERNATING-CFRRENT LABORATORY.

An alternating- current laboratory is being fitted up at 235 New Jersey

avenue SE. A storage battery for furnishing direct current for experimental

work and f«t>r power has been installed. Orders have been placed for

specially designed single-phase and multi-phase alternators, to be direct

connected to independent direct-current motors. Especial attention will be

given to the comparative study of the methods for determining wave form,

which in many practical cases departs so widely from the simplest type.

The determination of electrostatic capacity and the investigation of

dielectric-hysteresis will also be given special attention, as will also the

verification of standards of self and mutual inductance.
THE NATIONAL BUREAU OF STANDARDS. 15

For the verification of alternating- current ammeters and wattmeters a

set of Kelvin ampere balances, as well as considerable other apparatus, has

been purchased, and a low-voltage storage battery of large capacity will be

installed for supplying heavy currents. Facilities will be provided for the

verification of alternating-current voltmeters from the lowest to the highest

ranges. Instruments of various types have been ordered, and will be

calibrated by the aid of a high-voltage test battery, 1,000 cells of which

are to be immediately installed. One of the first problems will be to make

a comparative study of various t}7pes of alternating-current instruments

to determine the limits of error to which thev are liable and the influence

of the frequency and wave form on their indications. Provision will

be made for the calibration of direct-reading wattmeters, as well as the

commercial types of supply meters. Before this can be done for the public

it will be necessary to make a careful study of several different types of

alternating-current meters. Only a limited range of work can, however, be

attempted in the temporary laboratory, for lack of space and assistance.

MAGNETIC WORK.

Owing to the insufficiency of the force, no work along this important

line could be undertaken. Facilities will, however, be provided without

delay for the determination of the magnetic properties of materials, a knowledge of which is so important to manufacturers of electrical apparatus,

and for the verification of magnetic balances and other apparatus for the

determination of such properties.

Investigations as to the influence of treatment and chemical composition

on the magnetic properties of iron and steel would undoubtedly be of great

value to manufacturers, and will be taken up as soon as time permits.

PHOTOMETRY.

The importance of accurate standards for photometric measurements is

recognized by the Bureau. It will therefore endeavor to place at the

disposal of the lighting interests and the general public as soon as possible

means for verifying such standards.

The Hefner amyl^acetate lamp, notwithstanding its numerous and

evident defects, its reddish color, the influence of flame height, tempera-
16 ANNUAL REPORT OF THE DIRECTOR OF

ture, humidity, etc., upon its intensity, has been generally adopted as the

primary sta

satisfactory

dard. Only in the hands of ;i skilled observer are the results

and the numerous corrections which must be ;i ] »j »1 i < *<1 render ii<

use out of the queslion in industrial photometry. This has resulted in the

adoption or properly treated incandescent lamps as secondary sod ;is working standards, the luminous intensity depending only upon the voltage

applied. Variations in the intensity w ith use are eliminated l>v using the

secondary standards only for checking the working standards. The most

urgent demand will therefore be met l)\ providing facilities for the verification i >l su(di lumps.

( )nc of the rooms in the temporary laboratory 1ms already been fitted

up as a photometric laboratory, with the latest type of comparing apparatus.

Several Hefner lamps have been "purchased, and orders have been placed for

the necessary electrical apparatus, voltmeters, ammeters, wattmeters, resistance standards, and a precision photometer A battery of sixtv-six 200-

ampere-hotir cells has been installed for furnishing the necessary power,

and regulating rheostats have been constructed.

One of the sources of error in photometric measurements is due to the

difference between the color of the Hefner standard and that of the modem

sources of artificial illumination with which it is compared, and an extended

series of measurements bv different observers, skilled in photometry, is to be

arranged to studv this source of error and to eliminate errors arising from

the improper use of the Hefner standard.

While the most urgent demand is for properly verified standards of

candle power, it is highly important that the Bureau should make a comparative study of the different methods which have been proposed for

the determination of the "mean spherical intensity," upon which the

economic value of a lamp when used for general illumination depends.

The defects of the Hefner standard make it important to investigate

further the different methods which have been proposed for the realization

of a better primary photometric standard. Thus the " acetyl en e-in-oxygen"

lamp and the Nernst glower should be investigated, but the most promising

direction is that along which the Phvsikalisch-Technische Reichsanstalt has

been working for a number of years, that is, in the study of the radiation
THE NATIONAL BUREAU OF STANDARDS. 17

from the inside of a hollow body, the walls of which are maintained at a

uniform temperature, The intensity of the radiation emanating from the

interior depends only upon the temperature of the walls, and while the

methods for the measurement of the high temperatures involved in

photometric standards are not yet sufficiently precise, it is probable that

the temperature can be defined in terms of the radiation emanating from a

body at a lower and, therefore, more accurately measurable temperature.

Work along this line should be undertaken in conjunction with the other high

temperature researches. Provision will be made for the spectrophotometry

analysis of the light emitted by lamps, as this furnishes the best menus of

defining its quality.

Recent improvements in the construction of arc lamps, the commercial

advent of the Nernst glow lamp, the mercury arc, and the general

introduction of the Welsbach incandescent gas lamps, make it important

for the Bureau to provide for the investigation of questions concerning their

performance.

THE WORK OF THE OFFICE.

The office work includes correspondence, preparation of certificates,

purchases, accounts, records, library and archives, care of apparatus and

supplies, editorial work, and publication.

A steadily increasing correspondence has developed in connection with

the business and technical work of the Bureau. Requests for information

on the part of the general public and Government bureaus have been

numerous. Information concerning standards and standardization should

be fully available for the use of all interests concerned.

The card system has been applied in the business of the Bureau, the

main advantages being the ease of quick reference, convenience of

classification and rearrangement, facility of removal of useless matter, and

the unlimited expansibility. The vertical system for filing correspondence

has been adopted, and the numerical, alphabetical, and subject index

combined in a simple manner, to secure the merits of each, especially

facilitating subject reference. Each letter, order, or other paper received

or sent is numbered, and a record kept of source, destination, subject, to

whom referred, and file number. The alphabetical card index affords a

20378—03 3
18 ANNUAL REPORT OF THE DIRECTOR OF

complete arid quick reference to any paper received by or sent from the

Bureau

The accounting- of the Bureau involves the receipt and record of fees

for standardizing weights, measures, and measuring' instruments, the record

of appropriations and balances ; the checking-, record, and forwarding

of voucher^ for settlement ; preparation of statements for Auditor,

warrants, checking of disbursement records, and the annual accounting of

appropriations and fees.

APPROPRIATIONS, 10O1-2.

Toward the erectjion of a suitable laboratory, cost not to exceed 1325,000 $100, 000

Site, National Bureau of Standards 25, 000

Salaries, National Bureau of Standards, 1902 27, 140

Equipment of Laboratory, National Bureau of Standards, 1902 10,000

General Expenses, National Bureau of Standards, 1902 '. 5,000

Total .... 167, 140

t EXPENDITURES, 1901-3.

Appropriation.

Laboratory

Site

Salaries, Nationa

Equipment of La

J. Bureau of Standards, 1902 ...

moratory, National Bureau of Standards, 1902. General Expensts, National Bureau of Standards, 1902

Total . .

.

Disburse- ments.

Unfilled

orders.

Total.

1119. 20

25, 000. 00

21,959. 76

1,718. 46

3, 281.55

$119. 20

25, 000. 00

21, 959. 76

9, 930. 59

4, 918. 01

$8, 212. 13

1, 636. 46

52, 078. 97 9, 848. 59 61,927. 56

The wo

PRINTING AND PUBLICATIONS.

k of the year included the preparation of the necessary printed

matter, sucli as stationery, printed forms, and record books for the work

in the office! and laboratories. The planning of these forms involved the

determination of the routine to be adopted in the various brandies of the

work. During the year an official seal was designed and engraved by

f Engraving and Printing, more than thirty blank forms were

1 a number of record books designed for special purposes.

the Bureau

prepared, an

THE LIBRARY.

During the year the Bureau received about 700 volumes, 150 of

which were from Government departments and from private sources. The
THE NATIONAL BUREAU OF STANDARDS. 19

appropriation permitted the purchase of only a few of the books and

journals imperatively needed for the scientific work, and at the present time

new lists of necessary reference books have been laid aside for lack of

funds. An adequate reference library is a fundamental requisite in a

scientific and research laboratory. A librarian is urgently needed to take

charge of the books, to prepare a subject catalogue, attend to the work of

compiling needed bibliography, and to prepare journals and pamphlets for

binding. Such a librarian would be of great assistance to the technical

work of the Bureau in the preparation of technical bibliographies of

scientific subjects for immediate use in the practical work of the Bureau.

NUMBER AND VALUE OF TESTS COMPLETED DURING FISCAL YEAR EXDED JUNE

30, 1903.

For Government. For aublic. Total. Nature of test. Number. Value. Number. Value. Number. Value.

Length ' 35 $79. 15 123 $155. 30 158 $234. 45

Weight 109 102. 50 99 53. 00 208 155. 50

Capacity 251 171. 00 9 12. 50 260 183. 50

Temperature 75 128. 00 22 6.25 97 134. 25

Electrical 7 25. 00 7 25. 0'O Sundry 273 583. 70 52 325 583. 70

Total 743 1, 064. 35 312 252. 05 1,055 1,316. 40

The amount received from the public is made up as follows:

Value of tests completed for the public during fiscal year 1901-2 $252. 05

Received by United States Coast and Geodetic Survey prior to the organization

of the Bureau $0.50

Received during fiscal year 1901-2 256. 40

Received during fiscal year 1902-3 for tests completed 1901-2 22. 50

$279. 40

Received during fiscal year 1901-2 for tests not completed in that year 27. 35

252.05

Respectfully,

S. W. Stratton,

Director.

The Secretary of the Treasury.

O