G. Kaye. X-rays. Translated from the English, revised and considerably supplemented by E. V. Shpolsky. State Publishing House, Moscow—Leningrad, 1928. Pp. XIV + 376. Price, bound, 5 rubles 50 kopecks.

The book by Kaye, the author of a number of investigations in the field of X-rays, who has worked much on the solution of technical problems in this field, was received in England and America with great sympathy (from 1914 to 1927 it appeared in five editions). Many Russian roentgenologists and physicists are also familiar with it. In the preface to the first edition of the book the author writes of his task as follows: “This little book does not claim the role of a treatise or handbook on X-rays. Its purpose is to examine those of the methods or apparatus now in use which present themselves as new and valuable, and information about which is often scattered through various journals; it is devoted to the physical foundations of the most important principles of radiology, and at the same time it considers with equal attention the development both of theory and of experiment; finally, it attempts to give an idea of the historical development of this branch, beginning with Roentgen’s famous discovery and ending with the present year.”

With the present state of our knowledge of X-rays, with the diversity of the branches of knowledge that are now being developed with their aid, and with the extensive literature devoted to separate questions connected with X-rays, it is hardly possible to accomplish in one book all the aims set by the author in 1914. Nor can one now lay claim to this. At the present time world literature already contains many books, each devoted to the development of particular questions connected with X-rays. It is enough to mention the books of the Braggs, Ewald, Mark, Glocker, Siegbahn, and certain others. Kaye’s book may be regarded as having preserved the realization of one goal: to give the physical foundations of the most important principles of radiology. However, the revisions and additions made by the author himself in the subsequent editions of his book are insufficient for a simple translation of it to satisfy the possible circle of Russian readers. Therefore one may welcome the publication by GIZ not of a simple translation of Kaye’s book, but of a revised and supplemented one. The translation of the English text of Kaye’s book was made by A. A. Loontieva and is in general good and easy to read. In some places it would have been desirable to see other terms and expressions used: on p. 41, for example, we have “the worked tube often becomes better”; on p. 266 “atoms sitting on axes”; on p. 275 “a beam of X-rays not strictly parallel, but slightly converging at the end”; on p. 45 the name Roiti is rendered as Rioti, and there are several other oversights.

The extraordinarily difficult task of following the author’s program, preserving the character of the exposition and the general style of the book, and introducing into it the necessary corrections and additions, was carried out by E. V. Shpolskii quite successfully. The paragraphs newly introduced or revised by him supplement the greatly improved book with new material. The exposition of the additions is made in complete agreement with the general character of the book, so that it is not felt that they were given by another person. These additions or changes concern many questions and in volume amount to a third of the entire book. In them the reader

will find information on the principles of construction of modern high-voltage X-ray apparatus, on modern valve tubes (kenotrons), on methods of absolute measurement of the energy of X-rays, on protection during radiography from scattered rays (Roentgen and gamma rays), and also on the techniques and methods of X-ray spectral analysis. Along with these questions, E. V. Shpolsky gives the elementary information necessary for a clear understanding of the processes of emission and absorption, relating to the theory of X-ray spectra and to the application of quantum theory to questions of X-ray radiation. These latter additions somewhat alter the balance that previously existed in Kohl between questions of an applied and a theoretical character, in favor of theoretical information. To some extent this can be justified by the difference in time between the appearance of the complete edition of Kohl’s book and its Russian translation. Too wide a shadow is cast by purely scientific questions, in which X-ray radiation plays a large role, for there to be no references in a book dealing with the properties of this radiation to works devoted to these questions.

Some passages in the book may remain not entirely clear to a reader who has no supplementary knowledge of physics; such are, for example, the paragraphs on the role of the anode in the X-ray tube, on valve ionic tubes, on absorption spectra, and on fluctuations caused by X-rays. Possibly the experiment of Bothe and Geiger is unsuccessful. The following expressions are unsuccessful: “The whole basis of spectroscopy lies in Bohr’s equation” (p. 301). In pointing out the difficulties for quantitative analysis by means of X-rays (p. 319), it would have been possible to point out the possibility of replacing the photographic method by ionization.

These minor remarks should not diminish the general merit of all the work of making the necessary additions to Kohl’s book; and Kohl’s “X-rays,” with the additions of E. V. Shpolsky, may be recommended to all who are interested in this field as the first large book in Russian, giving, in sufficiently exhaustive scope and in elementary exposition, physical and technical information about this important kind of radiation for us.

Vl. Kaptsov.