K. W. F. KOHLRAUSCH. Radioaktivität (Handbuch der Experimentalphysik, herausgegeben von W. Wien, F. Harms und H. Lenz). Pp. X + 885, Akademische Verlagsgesellschaft, Leipzig, 1928, R. M. 80.

KOHLRAUSCH. Radioactivity.

The literature on radioactivity does not suffer from a shortage of thorough monographs. In the first place here, of course, one must cite Rutherford’s brilliant book (Radioactive Substances, Cambridge 1913), which, despite its respectable age, still retains all its significance and all its deep and keen interest. Among more recent books one naturally should mention the well-known Handbuch of Meyer and Schweidler, distinguished by great objectivity, completeness, and strict proportionality of its separate parts. Under such circumstances the author of a new, extensive monograph, not wishing his book to be a mere repetition of those already available, is placed in a rather difficult position. Kohlrausch has emerged from this difficulty very successfully and has created a book which, despite serious competition, possesses entirely independent significance and interest.

The device by which this is achieved is very simple: in contrast to Meyer and Schweidler, Kohlrausch not only does not strive to illuminate evenly all aspects of the doctrine of radioactivity, but consciously concentrates his attention chiefly on one aspect. A brief survey of the distribution of the material by number of pages will show what is meant: introduction — 16 pages; radioactive radiations — 640 pp.; laws of radioactive decay — 25 pp.; methods of measurement — 40 pp.; radioactive substances — 47 pp.; atomic nucleus — 70 pp. Thus Kohlrausch’s book is essentially devoted almost exclusively to radioactive rays, and dwells very little on radioactive substances. The small amount that is in the book concerning radioactive substances is an excerpt made, with the consent of the authors, from the corresponding chapters of Meyer and Schweidler’s book. On the other hand, everything that relates to rays is set forth not only quite originally, but also truly excellently. Exhaustive completeness and critical thoughtfulness of the exposition, a clear and lively language—all this makes Kohlrausch’s book indispensable for reference and, unlike most books of this type, extraordinarily interesting to read.

In the chapters devoted to radioactive rays, the author also departs from the order of exposition sanctioned by tradition and begins not with $\alpha$-, but with $\gamma$-rays. Such a departure is due exclusively to the author’s personal tastes and can hardly be justified by any substantive considerations. However, apparently no serious objections can be raised against this order either. The extensive chapter on $\gamma$-rays (170 pp.), which is an expansion of the author’s previously published monograph on the same subject (Sammlung Vieweg

Heft 87(88), is written with particular love and care, which is explained, of course, by the author’s active participation in the development of the problem of γ-rays.

In the chapter on the atomic nucleus, works devoted to fluctuations of radioactive decay are set out in detail, as are the works of Rutherford, and also of Kirsch and Peterson, on the artificial disintegration of elements and, finally, attempts to create theories of the structure of atomic nuclei.

Summing up, one may say without exaggeration that Kohlrausch’s book is one of the most interesting book novelties of the last year and a half. One cannot but regret, therefore, that its disproportionately high price makes it practically little accessible. Reprography does not know the methods of calculation employed by German publishing houses, but one involuntarily gets the impression that they have fallen into a “vicious circle”: the high price makes the book little accessible to private individuals; this compels the publisher to print books in small editions, and this, in turn, entails a further increase in price. In the interests of the development of science, one can only wish that a way out of this abnormal situation be found as soon as possible.

E. Shpolsky.