Riecke Lehrbuch der Physik. Herausgegeben von Prof. Dr. E. Lecher. Erster Band. Mechanik und Akustik. — Wärme. — Optik. 6. Auflage pp. XVI + 644. Leipzig 1918. Zweiter Band. Magnetismus und Elektrizität. 6. Aufl. pp. XIV + 636. Leipzig und Berlin, 1919.

The new edition of Riecke’s course, which has long since earned an honorable reputation, is so significant an event in the physical literature that it is necessary to mention it. In the hands of the editor of this new sixth edition, Prof. E. Lecher’s, an already excellent book has turned into a truly brilliant, entirely modern course. It is not a short elementary textbook, but neither is it a heavy Handbuch. The art of the author and of the editor of the new edition consists in their having managed to find the correct middle path. On the one hand, the exposition is not encumbered with mathematical insertions, which so often obscure for the beginner the very essence of the phenomena; on the other hand, the material is so extensive and varied that the book by Riecke—Lecher leads the reader directly to those problems of physics which form the living organism of the science. Nernst’s theorem, statistical physics, the “special” and general principle of relativity, Ehrenhaft’s experiments, vacuum X-ray tubes, cathode amplifiers, X-ray spectroscopy, quantum theory, the structure of the atom, and a great many other very contemporary questions find a place in the pages of this course. At times, however, it seems that Prof. Lecher is rather too intent on novelty and stops at subjects not yet firmly enough established to enter a textbook (Ehrenhaft’s negative “photophoresis”).

Thus, for the student, this book directly opens the path to the study of the original literature, and the numerous quotations (though not so abundant as to turn the book into a special survey) facilitate the approach to such study. — Of course, it would be very gratifying to see Riecke—Lecher’s book in Russian translation, but this is unlikely to be accomplished in the near future.

E. Shpolsky.