NEW BOOKS Kolloidchemisches Praktikum. By E. SAUER.21 x 14 cm.; ix 4- 112 pp. Berlin: Julius Springer, 1935. Price: 4.50 RM. This laboratory manual gives detailed directions for 140 experiments illustrating the preparation of colloidal solutions, the investigation of their mechanical, electrical, and optical properties, phenomena a t boundaries, the properties of gels and jellies, and the analysis of particle sizes chiefly by elutriation. The majority of the examples chosen are what may be called standard or classical; a few-e.g., the preparation of cadmium sulfide from the cyanide-are drawn from less familiar sources, while a number of experiments have been devised by the author himself. The directions are concise but clear, and students of average attainments should find no difficulty in carrying them out and in acquiring a fair knowledge of colloidal technique. The intelligent student will also notice the only serious error overlooked by the proof reader: to prepare colloidal sulfur according t o Raffo’s method he is instructed t o drop a solution of sodium sulfate into concentrated sulfuric acid; it should of course be sodium thiosulfate. The author says in the preface: “Only in rare cases will sufficient time be available at the universities for a practical course in colloids extending over a whole semester. It is, however, possible t o give a survey of colloid chemistry by using one or two afternoons only during one semester.” EMILHATSCHEK. Lehrbuch der physikalischen Chemie. By K. JELLINEK. Band V, Bogen 1-18. 25 x 16 cm.; 288 pp. Stuttgart: F. Enke, 1935. Price: 27 marks. The first part of the fifth and final volume of this well-known treatise consists, broadly speakipg, of three sections with the beginning of a fourth. The first section deals with surface phenomena and colloids, including electroendosmose, cataphoresis, clectrocapillary phenomena, and the Brownian movement. Since only eighty pages are devoted to this section, the treatment is often brief, but the mathematical deductions are clearly given and such typical experimental results are quoted as are necessary t o illustrate the applications of the theory. The second section (pp. 81-204) deals with homogeneous and heterogeneous reaction velocity, and modern aspects are represented by discussions of the work of Hinshelwood, MoelwynHughes, and Bronsted. A good feature is the detailed consideration of typical cases, and the rather involved theory is carefully explained. The section on heterogeneous systems includes activated adsorption. The theory of supersaturated solutions on p. 160 is given without mentioning the names of the authors, Jones and Partington. The third section deals with aspects of electrolysis falling within the range of the volume and includes a discussion of modern research on overvoltage. The section on the structure of matter, with which the fifth volume will mainly be concerned, is introduced by eighteen pages on the determination of the electronic charge. The present volume, although perhaps less detailed than the preceding ones, is planned p d executed on the same lines, and it may be recommended as a clear and able exposition of the subjects dealt with. J. R. PARTINOTON. 1161
