M57. Large Mollier Chart.

This chart presents in graphic form a complete table in the foot-poundFahrenheit system of the thermodynamic properties of ammonia, over the range of temperature and pressure useful in refrigerating engineering. It provides a rapid and convenient means for the solution of practical problems. The chart itself is about 16 inches high by 40 inches wide. It is identical, except for its larger size, with the chart already published as part of C142 and separately as M52. The larger chart will serve in those cases where either higher accuracy or reduced eyestrain is sought. Price,

10 cents.

M58. Technical Conference of State Utility Commission Engineers. This conference report gives a condensed record of the proceedings of the first annual conference of public utility commission engineers held at Washington, D. C., March 2 and 3, 1923. The report contains brief descriptions of the public utility investigations under way at the Bureau of Standards by members of the bureau's staff, papers on the grading of utility service, heating value standards for manufactured gas, and on the conservation of natural gas presented by commission engineers, a paper on grounding of electrical circuits and a review of the inductive interference situation by engineers of the bureau. In addition to the formal papers the report contains abstracts of the discussions of the papers presented to the conference. 80 pp. Price, 15 cents.

M59. Seventeenth Annual Conference on the Weights and Measures of the United States. (May 26 to 29, 1924.)

Contains addresses by the Secretary of Commerce and the president of the conference; papers and discussions on subjects such as maintenance of accuracy of scales in crcameries, administration of weights and measures in Porto Rico, New Jersey sale by weight law, Indiana bread law, Federal bread bill, recent decision of United States Supreme Court on Nebraska bread law, interstate status of package goods, scientific enforcement of law, elimination of short weight and measure, international bureau of weights and measures, uniformity of regulations for milk bottles, publicity, fraudulent marking of jewelry, calibration of vehicle tanks, the retail merchant, and methods of test of taximeters in various jurisdictions. Specifications and tolerances for fabric-measuring devices were finally adopted, certain changes were made in the codes of specifications and tolerances now in effect, and further steps were taken toward the development of specifications and tolerances for vehicle tanks. 147 pp. Price, 35 cents.

M60. Annual Report of the Director of the Bureau of Standards to the Secretary of Commerce for the Fiscal Year Ended June 30, 1924.

(For abstract see M22.) 38 pp. Price, 10 cents.

M61. 1924 Report of the National Screw Thread Commission. The 1924 report of the National Screw Thread Commission is a revision of the Progress Report published in 1921, M42, Bureau of Standards. The report has been completely revised and several new sections have been added. 176 pp. Price, 35 cents.

M62. Table of Brinell Hardness Numbers.

Increasing use of the Brinell indentation hardness test has created a need for a convenient table for converting the diameter of Brinell impressions into Brinell hardness numbers. The table gives both 3,000 kg B. H. N. for diameters of impressions between 2.00 and 6.99 mm by steps of 0.01 mm. (Dec. 17, 1924.) Card. Price, 5 cents.

M63. Report of Board of Visitors to Bureau of Standards of the Department of Commerce for the Secretary of Com

merce.

The 1923 report of the visiting committee on an examination and consideration of the work of the Bureau of Standards deals with the functions and achievements of the bureau. Its economic value is illustrated by several cited cases: $15,000,000 from the bureau's brake -lining investigation, $28,000,000 total to date from the research standardization for the hosiery industry, $40,000,000 annually from the tire investigations, and $100,000,000 annually from the motor-fuel investigations and standards. The report commends the proposal to acquire for the bureau a central power plant and a suitable housing for the bureau's master scale. 14 PP. Price, 5 cents.

M64. The Standard Weights and Measures of the United

States.

This is a reprint of the text of Scientific Paper No. 17, a brief description of the standards of length and mass accepted at different periods by the United States Government, to which have been added a Foreword and 17 pages of illustrations. 41 pp. Price, 15 cents.

SUBJECT INDEX OF ALL PUBLICATIONS OF THE BUREAU OF STANDARDS

(From its establishment, March 3, 1901, to June 30, 1925)

Since this is the only alphabetical index of the published work of the Bureau of Standards, the cross references have been made fairly complete. Topics subordinate to the main theme of a paper are also included if treated fully enough to justify citation. For example, under "Chronograph" will be found a reference to S65, the primary subject of which is the ratio of units. To index all such related terms, however, would make the index too long.

In using this index the reader should first look up a subject under the most specific term, for example, "Inductance" rather than "Measuring inductance." At best the indexing under general terms is necessarily incomplete.

The reader should further consult not only the key words of his topic but also their synonyms and antonyms, and related terms. For example, “Opacity" may be the primary topic of a study and the index would give pertinent references. "Transmission" and "Absorption," however, should also be referred to for additional citations. A more detailed list of the topics treated in the separate papers is given in the table of contents which precedes the text of each separate publication.

In addition to consulting the index to Circular 24, given below, the reader should consult also the supplemental index at the end of the current Supplementary List of Publications of the Bureau of Standards. These two indexes together form a comprehensive index of data and results of the bureau's published work. In other words, the index in the supplement brings the main index up to date.

Accelerator in hardening Portland cement, T174.
Accidents, elevator, statistics, T202.

Accumulator, see Storage battery.

Accuracy, polarimetric, $35.

Acetylene, colorimetric determination, S267.

flame, emissivity, S191.

selective radiation, S156.

spectrum, S362.

visible spectrum, S279.

radiation constant, S105.

forces on circular cylinders with reference to dynamical similarity, S394.

liquefaction, S123.

refractive index, $327.

Air-core transformer, S449.

Aircraft, use of radio direction finding, S353.

*For more specific reference see table of contents of the publication cited.

*For more specific reference see table of contents of the publication cited.