NEW BOOKS Die Aliialichloridelcktrolyse in Diaphragmazellen. By G. ANGEL. 19 x 13 cm.; 126 pp. Berlin: Verlag Chemie, G. m. b. H., 1933. Price: 12 hI. In this monograph the author has reexamined the whole basis of the theory of the electrolysis of alkali chloride solutions in diaphragm cells. I t is shown t h a t when a true steady state has been established the current efficiency can be expressed as a function of the alkali concentration in the catholyte; the exactness of the relations deduced has been tested by numerous experiments with sodium chloride solutions in cells of the horizontal diaphragm type. Physical properties of the electrolyte have been measured under various conditions, and the density, viscosity, and conductivity of both anolyte and catholyte a t various temperatures are related to t h e alkali concentration of the catholyte. Comparison of the theoretical relations for potassium and sodium chlorides indicates that, starting with solutions saturated a t room temperature, the current efficiency in the steady state should be lower in the former than in the latter case. This conclusion, which is a t variance Tr-ith previously accepted statements, is shoir-n to be borne out by experimental results. The theoretical discussions and experimental results constitute an important contribution t o the study of this complex subject and should prove of considerable value in the further development of technical cells and in the control of their operation. The main conclusions are summarized clearly a t the end of each section of the book, and the experimental data are set out in numerous tables and graphs. H. J. T. ELLISGHAM Die m o d e m e Atomtheorie. Die bei der Entgegennahme des Nobelpreises 1933 in Stockholm gehaltenen Vortrage von W. Heisenberg, E. Schrodinger, and P. A. hf. Dirac. 22 x 15 em.; 45 pp. Leipzig: Verlag S. Hirzel, 1934. Price: 2.50 RLI. This collection of three Nobel lectures on related subjects deals, in succession, n ith the uncertainty principle, n i t h the fundamental conceptions of ir-ave mechanics, and ~ i t the h theoryof electrons and positrons. The subjects are dealt x i t h i n a broad and general n a y , yet in sufficient detail in each case t o hring out the essential features. The advantage which every reader obtains from such a book depends on the mental background n hich he brings t o it, but all physical chemists who are acquainted viith the general notions of generalized coordinates, the quantum theory, and experimental physics will find these profound yet clearly written expositions of considerable interest, and nil1 gain from them a picture of the broad features of certain aspects of modern atomic theory. J. R. PARTINOTON.
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Pjlanzenthermodynamik. By KERT STERN. 22 x 15.5 cm.; s i 412 pp. Berlin: Julius Springer, 1933. Price: unbound, 32 RM;bound, 33.20 R l I . This book is divided into two parts. The first is an exposition of the principles of thermodynamics; the second a description of their application to processes occurring in plants. In the former the author’s stated object is to concentrate on those parts of the subject Tyith a direct application t o plants t o the exclusion of those n.ith little or no bearing on botany, but it is difficult t o see in what respect this object has been achieved. The method of treatment, in fact, appears to be essentially a con1127
