3 AUGUST 1918, Page 16

The Reproduction of Sound. By Henry Seymour. (W. B. Tattersall,

10s. 6d.)—In the last twenty years the talkingmachine has passed definitely from the stage of an unusually objectionable and blatant toy to that of a musical instrument of recognised artistic and scientific value. Nobody in Great Britain has contributed more to this result than Mr. Henry Seymour, who has embodied his unique experience as inventor, manufacturer, and consulting expert adviser in the present excellent volume. It covers the entire field of mechanical sound-recording, from the preparation of the original blank cylinder or dise upon which the record is taken, to the turning out of the finished product ready for the market. The different types of machines used for reproducing are described in clear detail, and their characteristic meritsanddefectsindicated ; and there are particularly interesting chapters on methods of recording sound by the agency of light and magnetism, which, although little more than laboratory triumplfs now, may revolutionize the whole industry in the near future. The illustrations are numerous and helpful ; but we lament the absence of an index from what will evidently be the standard work on its subject for a long time to come. It should appeal not only to the student and technical worker, but to that widening class of amateurs who desire to use their instruments to the greatest advantage, and to know how far mechanical improvement is possible, and in what direction to look for it.