A. Sommerfeld. Atombau und Spektrallinien. 2nd ed. Braunschweig, 1921, pp. XIV + 583.

The discovery of radioactivity and the associated theory of the structure of the atom, proposed by Rutherford and further developed by Bohr, has at present led Rutherford, as is well known, to the decomposition of the positive nuclei of elements into their constituent parts, which is undoubtedly an era in the field of physicochemical doctrines. On the other hand, the Rutherford–Bohr theory of the atom has also yielded remarkable results in the theory of the structure of spectral lines, so that it now seems absolutely necessary to bring together everything obtained so far and to provide guiding threads for future work. All this is splendidly accomplished by A. Sommerfeld’s excellent, clearly written book, by the author of a number of fundamental works in the field of the doctrine of atomic structure in connection with its spectrum. The book first appeared in 1919 and came out in 1921 in a second edition—proof that both its content and its mode of exposition can count on physically and chemically educated readers. Here in Russia a translation is being prepared (organized by Prof. D. A. Goldhammer), and one can only wish that this translation may see the light as soon as possible and exert on Russian science the influence that it is capable of exerting.

P. Lazarev.