The Restless Atom.

"The Restless Atom belongs to the Science Study Series published by the Physical Science Study Committee of Educational Services, Inc., w h o s e main purpose is to provide collateral reading for the secondary school physics program now being developed by the committee. However, the level of presentation is aimed not only at the high school student, but also at the college undergraduate and the general public, by offering to them "the most stirring and fundamental topics of physics, from the smallest known particles to the whole universe." In keeping with this objective, Romer's book is devoted to the discovery of radioactivity and the disentanglement of the laws of spontaneous transmutations of atoms during the 20 years from 1895 to 1915. The author succeeds in fulfilling the aims of the series since his presentation is accurate, but at the same time skillful and sufficiently lively to hold the interest of the reader. The work described in the book was intimately interwoven with obtaining the definite proofs for the existence of atoms and elucidating their structure. The author even writes in his "This is a book about the experiments by which we have gained one section of our knowledge of atoms and the way in which they behave." But if this was his primary aim it is hard to understand the omission of certain material which would have rounded out the subject of the book without appreciably adding to its bulk. (1) More might have been said about the discovery of the electron, which was entirely independent of Roentgen's x-ray discovery although almost contemporaneous with it. Romer regards the x-rays as the beginning of modern physics, but the conception of the electrons was at least of equal importance. It is mentioned in the book that J. J. Thomson was the discoverer of the electrons but nothing is said about the circumstances"