Handbuch der Radiologie. Vol. III, Leipzig. 1916. Glimmentladung und Positive Säule by E. Gehrcke, R. Seeliger. Lichtelektrizität by W. Hallwachs.

The splendidly conceived, extensive course of radiology, begun by the publication in German of Rutherford’s classic work on radioactive substances, has now been supplemented by a substantial third volume, comprising monographs by Gehrcke, Seeliger, and Hallwachs.

Written by the outstanding specialists of their field, the chapters of this third volume of Handbuch der Radiologie constitute an excellent reference book on the complex and modern questions connected with discharges in gases and with photoelectricity, and are indispensable aids for persons engaged in research in this area. In the study of photoelectricity, the literature of the subject has been taken into account up to October 1915, and this makes the book a valuable aid for bibliographical inquiries on the given question.

P. Lazarev.