Absolute Measurements in Electricity and Magnetism

Abstract

ALL physicists are familiar with the first edition of this important work, which, completed in 1893, has long been regarded and used as a standard treatise on electrical measurements. In introducing the second edition Prof. Gray refers at the outset to a certain lack of interest shown by physicists at the present time in the theory and practice of absolute measurements, and it is undoubtedly the case that, in our universities at any rate, the subject receives less attention than was formerly devoted to it. The principal reason for this change may be traced to the nature of such work as the experimental determination of absolute electrical units, and the accurate comparison of secondary standards with them, and also to the great importance which work of this kind possesses. Few, if any, of our university laboratories are sufficiently well equipped for the prosecution of researches in which the construction of apparatus and the carrying out of measurements of the highest precision are involved; and so necessary is this work recognised to be that special laboratories, such as the National Physical Laboratory in this country, and the Bureau of Standards at Washington, have been established, at which it can be more effectively organised and carried out, and at which the research worker in any of the universities may have his measuring instruments accurately standardised. Thus the apparent decline of general interest among physicists in methods of absolute measurement is not due to any diminution in the importance of the subject, but to the fact that the practice of these methods is now more concentrated in institutions specially equipped for the purpose.

Absolute Measurements in Electricity and Magnetism.

By Prof. A. Gray. Second edition, rewritten and enlarged. Pp. xix + 837. (London: Macmillan and Co., Ltd., 1921.) 42s. net.