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Bureau of Standards.
The Constitution vests the Federal Government with power to "fix the Standard of Weights and Measures," and from the beginning of the Republic many of the foremost statesmen and scientists have worked assiduously to bring our system of weights and measures to a more satisfactory and scientific condition. Washington recognized this as one of the important subjects committed to Congress by the Constitution, and repeatedly urged the necessity for uniform and reliable standards. In 1790 Thomas Jefferson, Secretary of State, was directed by Congress to investigate this subject, and after a most careful consideration submitted a report in which he suggested important reforms, which were not, however, adopted.
A reference to the subject of weights and measures appears in the act approved March 2, 1799 (R. S., 2627), where it was ordered, among other things, that the surveyor of each port of the United States should "from time to time, and particularly on the first Mondays of January and July in each year, [examine and] try the weights, measures, and other instruments used in ascertaining the duties on imports, with standards to be provided by each collector," Apparently this act was not enforced, probably for the reason that no standard had been adopted by Congress or by the Treasury Department. In 1817 President Madison reminded Congress that nothing had been accomplished in reforming and unifying the weights and measures, whereupon the whole subject was referred to John Quincy Adams, then Secretary of State. Mr, Adams, after four years of research, prepared a report which has become a classic in metrology; in it he advised the adoption of a universal standard by international agreement.
By Senate resolution of May 29, 1830, the Secretary of the Treasury was directed to have an examination made of the weights and measures in use at the principal customhouses, and, as was expected, large discrepancies were discovered. As a consequence, the Secretary of the Treasury directed that standards be adopted by the Treasury Department, and that copies be made and distributed to the various customshouses. The avoirdupois pound was adopted as the standard of weight, and the distance between certain lines on brass bar in the possession of the Department, and supposed to conform to the English yard, was taken as the standard of length. In June, 1836, Congress directed further that the Secretary of the Treasury should furnish each State with copies of these standards.
By act approved July 28, 1866, the use of the metric system of weights and measures was legalized, and the Secretary of the Treasury was directed to furnish each State with a set of standard weights and measures of this system.
In 1875, more than half a century after Adams had recommended a conference between nations for the purpose of establishing worldwide uniformity in standards, such a conference was held, and as a result there was established in Paris a permanent International Bureau of Weights and Measures. The bureau thus established undertook the construction of prototypes of the metric standards, and in 1889 these were ready for distribution among the seventeen nations represented at the international conference. Two meter prototypes (standards of length) and two kilogram prototypes (standards of mass) were sent under seal to the United States by special messengers, and were opened at the White House in the presence of the President, the Secretary of State, and a distinguished company of scholars.
The custody of the standards referred to above, and the execution of the provisions made by Congress, remained until July 1, 1901, under the direction of the Superintendent of the Coast and Geodetic Survey, Treasury Department, in his capacity as Superintendent of the Office of Standard Weights and Measures. The facilities of the latter office were exceedingly limited, and the exercise of its functions confined to departments of the General Government and the States.
The act of March 3, 1901, established the. National Bureau of Standards, and made it an independent bureau of the Treasury Department, where it remained until, on July 1, 1903, it became a part of the Department of Commerce, under the provisions of the law establishing the Department. The name "Bureau of Standards'' was adopted by order of the Secretary on July 1, 1903.
Since 1901 the Bureau has grown as funds were provided to enable it to take up more fully the functions prescribed in its organic act. The relative urgency of the several lines of activity fixed the order and extent of their development. The scope of weights and measures had broadened in recent times to include power, light, heat, electricity, refrigeration, and services of other kinds, which must be measured and for which standards and methods of measurement are needed. Not less urgent are standards of quality, which rest upon the properties of materials, and which for certain materials are partially defined in "specifications." Units and standards are here needed relating to physical and chemical properties in addition to those of dimension and weight. The Bureau aims to meet this need by the development of standard materials, standard specifications, and standard methods of test for the properties of materials.
Few subjects directly affect more people than weighing and measuring, since practically all products involve measurement, whether grown in the soil or manufactured. Construction, commerce, and daily trade are based upon measurement. Measure and money are the two factors which fix price, and measurement is the basis of science and technology. The Bureau's functions touch closely all who design and make, buy and sell, transport, or utilize materials, energy, or other services which require accurate standards and measuring instruments.
The Bureau has taken up as fully as possible the special functions prescribed by law, which may be summarized as follows:
(1) The custody of the standards, which involves their care and preservation and the varied researches necessary to maintain their constancy.
(2) Comparisons of standards for States, municipalities, institutions, and the general public, including those used in commerce, manufacturing, and science, assuring to the public accuracy at its source - in the factory and the industrial laboratory.
(3) The construction of new standards demanded by scientific and technical progress on the basis of the best available data and new researches at the Bureau, and whenever practicable by international agreement.
(4) Standardization of measuring instruments for manufacturers as a test of their output, or for the user that he may verify instruments or materials independently.
(5) Technical research on problems connected with standards research which in many cases limits the rate of progress in a given field.
(6) The determination of physical constants and the properties of materials - the exact data relating to materials and energy which underlie technical and industrial work, and for which direct reference to the fundamental standards is highly desirable.
(7) The determination of the properties of materials, such work being based upon the modern view that quality may be measured and standardized exactly as dimension and weight may be, although the problems may be difficult and require advanced research.
The organization of the Bureau is a practical grouping of the several classes of work - scientific, clerical, and mechanical. The divisions of the scientific work are electricity, weights and measures, heat, light, and chemistry. The technical operations also include engineering instruments and the investigation of materials. The clerical work comprises publication, records, library, accounts, certificates and correspondence, stores, and shipping. The mechanical staff has the operation of the engineering plant, care of buildings and grounds, construction in the instrument shop, cabinet shop, and the shop for glass blowing and glass working. The Bureau aims to attain steady progress in experience and knowledge among the employees in its several lines by a series of graded positions, and by providing facilities and opportunities, such as a technical library, journal meetings, and encouraging evening study to supplement their practical experience. This policy stimulates interest and efficiency.
The work of the Bureau has its main sanction as the legal custodian of the standards and also on account of the fundamental character of the investigations undertaken and the precision attained in such researches. In all of its work the Bureau aims to cooperate fully and directly with all interests concerned, since only in this manner can all points of view and sources of information be regarded.
When international standards are involved, the Bureau cooperates with the standardizing institutions of other countries and with the International Bureau of Weights and Measures. The international agreement as to the precise value of the candlepower as a unit of light is an example. While such fundamental standards are still relatively few, the derived standards, such as standards of light, color, composition, combustion, efficiency, and other quantities which are developed as industrial and scientific needs multiply, steadily increase in complexity.
Sets of the national standards have been supplied to every State of the Union, and these are verified from time to time at the Bureau of Standards. These sets serve to regulate the local measures used by county sealers for inspection of trade weights and measures. In all of such work the Bureau cooperates with State governments and officials by holding annual conferences, assisting in the technical details of the inspection service, and giving advice concerning new legislation.
The Bureau also cooperates with the national technical societies in developing uniform standard nomenclature, improved specifications, more exact methods of measurement, and more reliable and convenient forms of standards. The manufacture of measuring appliances is now a large group of industries, and in testing the standards used to make measuring appliances the Bureau is indirectly distributing precision in all branches of commerce and trade. To the general manufacturer the Bureau makes available its facilities by standardizing the measures by which he makes his product and upon his request the product itself may be tested. Manufacturers also refer technical problems to the Bureau, and wherever possible the Bureau aims to serve as a clearing house for technical information upon subjects within its field. The large number of inquiries by mail afford another medium for giving information upon these subjects - data which often may be directly applied in commerce, manufacturing, research, and daily trade. The need for a clearing house for such information needs no emphasis.
Length measures in great variety - gauges, bars, rules, tapes level rods - are standardized under known conditions of temperature and manner of support. Researches are made as to the design and use of such instruments, as well as their change with heat. All length standards used in manufacturing, in engineering - whether measuring lands, laying out buildings or other structures, or making maps and charts - or in scientific work must come directly or indirectly from the Bureau. Likewise the Bureau is the legal custodian of the standards of mass, and all makers of weights and balances and weighing instruments, from the most delicate used by chemists and physicists to the heaviest used in commerce, depend upon the Bureau for their standards.
Each year many thousand glass measures - flasks, pipettes, burettes, cylinders, and other forms used by chemists and others - are tested. Such tests are made by determining accurately the Volume of distilled water contained or delivered by the vessel at a certain temperature. Cubic-foot standards are also verified for use in testing gas and water meter provers. Likewise each year hydrometers in large numbers are tested, mainly for use by the Internal-Revenue Service to measure the densities of liquids in order to assess the proper tax. The Bureau is called upon also to determine densities of solids, liquids, and gases in special cases. These tests of length, mass, and capacity are fundamental, and with time form the basis of more complex measure of energy and the properties of materials. Many of the tests requested require the development of special apparatus and methods.
The importance to science and industry of correct standards and uniformity of measures of length, mass, and capacity is apparent, but it is equally important that standards be provided for the measure of electricity, heat, light, pressure, power, and other quantities. Moreover, the standards here involved are far more complex. Their preparation and comparison involve measurements and research of a high order in practically all branches of physics and chemistry. This work includes standard measuring instruments for temperatures ranging from the lowest to the highest attainable; the establishing of the standard temperature scale, and the determination of standard heating values of combustibles; and testing of pyrometers for measuring the high temperatures used in the steel, glass, pottery, and other industries. The standards and instruments of the electrical industries are no less important or varied in their nature. They involve as fundamental units those of electrical resistance and electromotive force, as well as those of capacity, inductance, and magnetic quantities. The Bureau maintains also a laboratory for preparing and testing standards of illumination used in the manufacture of electric lamps or the testing of gas, oil, and other illuminants. The optical work of the Bureau also requires its special units and standards, for the special optical problems involved, the tests of optical materials and instruments, and the determination of optical constants of industrial and scientific importance.
Standards for manufacturers are not constructed at the Bureau of Standards except in rare cases, although the Bureau has designed standard weights and prepared specifications for the several grades. In general, standards are purchased from the makers of standard measures and sent to the Bureau from time to time for comparison with the Government standards and certification of errors. The degree of precision with which they are compared is planned to meet the exact needs - to avoid at once needless over-precision for the usual cases and also to insure the adequate high precision where that is required for more fundamental or exacting work. The nice adjustment of the degree of precision to the specific case in hand requires the experience and judgment of the specialist.
The testing of water, gas, and electric meters practically concerns all who utilize such services. These services should, of course, be as accurately measured as are the ordinary articles of trade, and yet proper provision is often wanting for impartial tests of the accuracy of such meters. While the public may suffer loss through faulty meters for which proper testing facilities are inaccessible, yet suspicion may exist without cause, and in such cases it is equally important that the accuracy should be authoritatively attested. Most of this work is for manufacturing or central-station plants or for municipalities.
The work of testing materials is another important branch of the Bureau's functions. Public safety rests upon the certainty that the materials used for buildings, bridges, railroads, and other structures are of sufficient strength and stability. The time has passed when the strength of materials can be taken for granted. With the rapid increase in the height of buildings, length of spans of bridges, and speed of transportation new problems in safety and efficiency arise, which should not be left to guesswork or even personal judgment. Positive tests by assured methods alone can guarantee that, to begin with, the materials are properly selected for the work. By means of strain gauges and other means, the finished structure may be studied under service conditions. Experience is the ultimate test, but until the knowledge of materials is sufficiently complete the best substitute when judgment must be formed in advance is based on the laboratory test. The Bureau cooperates with other agencies in placing the testing of materials upon a scientific basis as fully as possible.
The growing appreciation of the vast waste due to defective materials and their misuse has raised the whole question of efficiency. Adequate testing or measurement is the keynote to the solution of the central problem. The testing of Government supplies is an illustration. In this work the various branches of the Government are cooperating with the Bureau and the purchasing officers in amending the faulty definitions, varying practices, and imperfect specifications, and providing suitable working standards of quality and methods of testing. The development of specifications has been made the subject of special conferences at the Bureau, attended by Government experts, manufacturers, and users, and the results obtained in the case of electric lamps, Portland cement, paper, and other materials show the value of such work. Among the more important groups of materials tested are metals and metal products, ceramics, cement and concrete, lime, stone, wood, bituminous materials, paint materials, inks, paper, textiles, rubber, leather, adhesives, and a large range of miscellaneous manufactured products.
The Bureau of Standards is located in the northwest section of Washington, D. C., at an elevation of 350 feet above the Potomac River, on a natural hill site of about 16 acres - a location admirably suited to its work, being practically free from mechanical and electrical disturbances. It occupies a group of five buildings, each of which was designed especially for the purpose for which it is used. In addition, it maintains laboratories in Pittsburgh and Northampton, Pa.
Besides an extensive modern equipment of scientific instruments and apparatus for experimental and testing work, the Bureau's facilities are in many respects unique, since the range of work is so varied. In the heat division temperature ranges are available from that of liquid air to the heat of a vacuum electric furnace; in electrical work wide ranges of current are available; in chemical work the usual facilities are supplemented by many special services. For the experimental work electrical power, refrigeration, steam, gas, compressed air, vacuum, liquid air, freezing brine, time service for precision purposes, and many other facilities are available.
The Bureau is provided with a technical library of more than 11,000 volumes, chiefly on physics, chemistry, and technology, and regularly receives about 300 journals related to subjects in its field of work. The Bureau has issued more then 350 publications giving the results of its scientific work and describing the various lines of testing now going on. These are available for public distribution.