fications to be an assembly of the various smaller specifications as listed. Work is continuing on other parts of the specifications with a view to standardizing all items which may be found to be practicable.

During the fiscal year standardizing rules were also adopted for attribution of certain diseases (gastric ulcer, cardiovascular diseases, leprosy, and the blood dyscrasias, tuberculosis and complications) to results of World War service, as the basis of disability compensation payments; additionally percentage standards of reduction in earning capacity from the various stages of gastric ulcer were adopted, replacing previously indefinite standards. In other respects, the standards embodied in the 1925 Schedule of Rating Reduction in earning capacity for disability previously reported on were retained.

V. NATIONAL BUREAU OF STANDARDS

An outline of the origin and functions of the bureau is given in the 1927 Standards Yearbook. Circular No. 1 and the 1929 annual report of the director should be consulted for a more comprehensive survey of the bureau's work.

RELATION TO GOVERNMENTAL AGENCIES

The relation of the bureau to the various Federal, State, and municipal governmental agencies is outlined briefly in the 1927 Standards Yearbook.

RELATION TO SCIENCE, COMMERCE, AND INDUSTRY

PUBLICATIONS

The results of the bureau's work are made available in printed publications. Approximately 1,700 pamphlets have been issued to date. Releases to the daily press give briefly the outstanding features of the bureau's activities from a popular point of view. Technical abstracts are prepared for the use of scientific and technical journals. New knowledge of general or pure science and results of direct application in the industries are published in the Bureau of Standards Journal of Research, which is issued once a month. This journal is obtainable on a subscription basis. Compiled technical or administrative matter is issued as a circular, for example, the standard petroleum oil tables, properties of aluminum and light alloys, test schedules, recommended specifications, and the like. Codes and reference texts, for example, the codes of electrical and logging practice, and the manual for weights and measures officials, which must be carried about by the user, are issued in a series of pocket size handbooks.

The program for the simplification of commercial practice leads to definite proposals known as Simplified Practice Recommendations, while agreements on the desirable minimum quality of products are published as Commercial Standards. Charts, conference reports, material not suitable for other series appear as Miscellaneous Publications.

and

The bureau's Technical News Bulletin is a monthly periodical containing progress reports of work in the laboratories, brief data on completed investigations, notices of important conferences, and lists of new publications by members of the staff in the bureau's series and in technical journals.

The first issue of a new periodical known as the Commercial Standards Monthly appeared in July, 1929. This is a review of progress in the field of commercial standardization, both at the bureau and elsewhere. Brief references in nontechnical language are also published on the progress of the bureau's research and testing work. The bureau also prepares letter circulars on specialized subjects for use as replies to inquiries by mail. The 268 letter circulars prepared to date cover a wide range of subjects and represent material not yet ready to be included in the printed series. In addition to

the Government publications, papers on subjects within the respective specialties are printed in outside journals.

The publications of the bureau are sold by the Superintendent of Documents, Government Printing Office, Washington, D. C. Subscriptions may be placed in advance for the Journal of Research, the Technical News Bulletin, and the Commercial Standards Monthly. The bureau issues a descriptive list (Circular No. 24, together with annual supplement) of its published material. Announcement cards giving titles of all new publications in the bureau's series are sent on request to those concerned with the work.

RESEARCH AND TESTING

RESEARCH

Research on problems arising in connection with standards is by act of Congress a primary function of the bureau. Such work includes the devising of methods and apparatus for the precise measurement of standards, the frequent intercomparison of standards to determine their permanency, and the evaluation of standards by absolute methods.

Physical Constants. The precise determination of certain physical constants and of certain properties of materials is closely related to the establishment of standards. The standard temperature scale, for example, is defined by a number of thermometric fixed points, such as the boiling point of oxygen, the freezing and boiling points of water, the boiling point of sulphur, and the freezing points of silver and gold. Careful redeterminations of imported physical constants, such as the Newtonian constant of gravitation and the mechanical equivalent of heat, lead to more precise evaluations of these widely used "constants." The determination of the properties of saturated steam under high pressures finds immediate application in the design of steam turbines, while new data on the properties of ammonia and carbon dioxide have corresponding uses in refrigeration engineering.

Research Associates. Much of the bureau's research is directed to the application of science in commerce and industry. The research associate plan permits industrial associations or groups to place qualified men at the bureau for intensive study of selected problems approved by the Director of the National Bureau of Standards. Such men utilize the bureau's laboratory facilities and equipment and have the same status as any bureau employee except that their salaries are paid by the supporting group or association.

The work of a research associate on problems of concern to an entire industry is one of peculiar trust. Research results are immediately available to the industry concerned and are frequently printed in bureau publications. Devices or processes developed during research may not be patented for the benefit of the individual or the group, but are for the free use of the industry, the Government, and the public. Correspondence relating to the work of the research associate is conducted through official channels except on purely personal matters.

A list of the research associates and projects under investigation arranged according to sustaining organizations is given in the following table:

1 For further details,[see B. 8. Circular No. 296.