In addition to the tests and comparisons made by the Bureau of Standards, its work includes such researches as are involved in the establishment and maintenance of the various standards and units of measurement, the development of measuring instruments and methods of measurement, the determination of physical constants and the properties of materials. The results of these investigations are published in pamphlet form, and in the following pages is given a classified descriptive list of these papers. They cover a wide range of subjects in the field of physical measurements and are issued for general distribution to the scientific, technical, and industrial interests concerned with the subjects treated. The papers will be sent upon request and may be designated by the numbers which precede the titles in the list. This list will be revised from time to time, and subsequent issues will be sent to those who request it. It is assumed that individuals generally are interested in a particular class of work; hence this method of distribution has been adopted in order that each may secure the particular information desired.

These papers are also bound from time to time in the form of a bulletin which is sent upon request to public libraries, educational institutions, scientific societies, and other institutions where a complete file is essential, also to a limited number of persons especially concerned with the work of the Bureau as a whole.

The regulations under which tests and comparisons are made by the Bureau and other general information concerning its work are issued in the form of circulars which are sent upon request.

S. W. STRATTON,

Director.