Curt Schmidt. Das periodische System der chemischen Elemente. pp. 140. Leipzig, J. A. Barth, 1913.

— The honor of discovering the periodic law was disputed by three countries: England (Newlands), Germany (Lothar Meyer), and Russia (D. Mendeleev). Only at the end of the last century did this honor begin to be recognized as belonging to Russia. Germany proved least generous in this respect. All the more gratifying, therefore, was it to see a new book, described by its author as “the first monograph of German origin,” which begins with a dedication: “To Dmitri Mendeleev,” and from whose pages Mendeleev’s name never disappears. The author constantly emphasizes the philosophical significance of the very idea of the periodicity of the elements, and places Mendeleev’s law at the foundation of a whole series of constructions concerning the nature of the chemical elements.

Written for a broad circle of readers, the book begins with the history of the question. Then follows an exposition of the periodic law in Mendeleev’s formulation, with the history of the famous discovery of the elements predicted by Mendeleev—scandium, gallium, and germanium. Comparatively little space is given by the author to the description of the properties of the elements themselves. In this respect the book falls far short of the Russian monograph: L. Chugaev. The Periodic System of the Chemical Elements. St. Petersburg, 1913.

Among the new and interesting chapters one should note the chapter on isotopy, with the work of Fajans and Aston, and on Rutherford’s model of the atom. Of interest is the chapter on the spatial representation of periodicity. Further, the latest variants of the periodic law are presented (van den Broek, Adams, K. Schmidt, and others); then the changes in hypotheses introduced by the study of the X-ray spectra of the elements (Moseley), the concept of the element’s ordinal number (Rydberg), and the book concludes with an account of attempts to explain the nature of the elements (the hypotheses of Lockyer, Nicholson, and Radulescu).

The author’s special attention is directed to the very essence of the periodicity of the elements; and, by setting forth the principal stages in the development of views in this direction, the author makes the book extraordinarily interesting and substantial. Naturally, the latest interesting achievements of science (Rutherford’s work on the structure of the atom, Fajans’s table of the elements) are not in the book.

O. Magidson.