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give them a well-rounded course in analytical chemistry. I n fact a small section relating to the detection of metals used in dentistry is included especially for the predental students. It is the opinion of the reviewer that i t will serve this purpose well and also he a good text for chemistry majors, who on account of the necessity of taking more specialized courses cannot have much more than a year for analytical work. At 'least i t will give them a good foundation course which can he followed by the more advanced analytical courses. The hook is divided into four parts; Fundamental Principles; Qualitative Determination of Radicals; Quantitative Determination of Radicals; and the Appendix, which contains the usual directions for making solutions, solubility tables, logarithm tables, atomic weights, etc. The first part (105 pages) presents in a dear and understandable manner the theoretical principles t h a t are applied in analytical separations. These include the various forms of equilibrium, ionization, solubility product, p H values, c o w plex ions, oxidation reactions, and the colloidal state. I n each division the principle is discussed with particular reference t o the analytical application. Each chapter is concluded with an excellent summary and a number of exercises or problems. The second part (158 pages) deals with the customary qualitative analysis scheme. The properties of the metallic ions are first studied by means of preliminary experiments and then after a discussion of these properties the directions for analysis are given and followed by explanatory notes. The systematic procedure does not differ markedly from that ordinarily used and need not be described in detail. The detection of anions is very briefly dealt with. Preliminary tests such as head tests, flame tests, ignition, etc., on solid materials are omitted entirely. The third part (158 pages) covers the quantitative part of analytical chemistry. It includes a discussion of accuracy and
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JANUARY, 1932
significant figures, calibration of weights and volumetric apparatus, and typical gravimetric and volumetric determinations. The directions in this part are exceptionally detailed and clear and should be easily followed by a student just beginning quantitative. Furthermore, he should, with very little effort, understand what he is doing for every step in the procedure is explained and its relation t o the qualitative scheme is indicated. Thus the student correlates his new knowledge with his old. The inevitable errors of a first edition are present hut the reviewer found none that should cause serious difficulty in understanding the subject matter. CARLOTTO UNIYBRSITV 01
MAINS
OIONO, M A ~ B
Physical Chemistry. An Elementary Text Primarily for logical and &medical Students. Lours J. GELESPIE,Ph.D., Professor of Physical Chemical Research, Massachusetts Institute of Technology, Formerly Fellow Rockefeller Institute of Medical Research, then Biochemist of the United States DepartL e n t of Agriculture. McGraw-Hill Book Co., Inc., New York City, 1931. ix 287 pp. 43 Figs. 13.5 X 20.5 wn. $2.75.
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This hook is especially intended t o he of service t o those students who are pursuing premedical or biological courses. The hook contains twenty-eight chapters, discussing the principal topics found in the general textbooks on physical chemistry. It is of significance, however, that the author has omitted a chapter on cob loids and includes the physical properties of colloids in several of the other chapters. Among the chapters, the subject matter of which is treated a t length and special applications made t o the biological sciences, are the chapters on "Cells for the Determination of Hydrogen-Ion Concentration of Activity," "Buffers and Titration Curves." "Indicators." and "Donnan Equilibrium." Throughout the text the author has made an effort t o
VOL.9, No. 1
RECENT BOOKS
apply physical chemistry t o the problems of biology. The author has adopted a research point of view which is helpful to the student in applying physical chemistry as a valuable tool in carrying out biological investigations. I n the chapter on surface tension, it is regretted that the author does not make mention of the relation of surface tension in the modern theory of cell antisepsis. I n the same chapter mention is made ' of the fact that sodium salts form oil-inwater emulsions and calcium salts favor the formation of water-in-oil emulsions. The antagonism of sodium and calcium in biology is pointed out. It should be mentioned, however, that this antagonism of inverting emulsions is not a specificity of the calcium ion but the same condition would obtain with magnesium and other divalent ions. Reference to Harkin's theory of orientation would aid the students in understanding the phenomenon of emulsions and emulsion reversibility. The reviewer feels that the matter of buffer capacity is not treated a t as great a length as it should be in a treatise of this kind. Its many references to biology, both in the plant and animal kingdom, are neglected. I n the mind of the reviewer the paragraph on errors tolerated in the calculation of pH would be made plainer t o the student if a table showing the relationship between hydrogen-ion concentration and pH were included. Furthermore, i t might he advantageous to emphasize that a difference in pH units in the neutral region of the pH scale is of less significance than the same numerical change on the extreme acid side of the scsle. Oftentimes this f a d is difficult for students t o grasp. The author fulfils his purpose in writing this book, that is, to present a practical working text in physical chemistry for students of biology. His style is precise and direct, and the student is not inundated by the mathematics presented by the author. J o m C. KRIINTZ,JR. STATE D s ~ ~ n r r a wo*r HRALT" BALTIIORE,MASYLIND
197
Photochemistry. D. W. G. STYLE,Ph.D. With a preface by A. J. ALLMAND, M.C., D.Sc., F.R.S., Professor of Chemistry in the University of London, King's College. E. P. Dutton and Company. Inc., 96 pp. New York City, 1930. v 9 Figs. 16.5 X 10.5 cm. $1.10.
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This little volume is designed t o afford an approach to the subject of photochemistry for physicists and chemists who have interested themselves little in the subject. The author has succeeded admirably in attaining his purpose and one feels safe in remmmendjng this work not only t o those who pretend t o know nothing about the subject, although possessing a good background of knowledge in chemistry and physics, but likewise t o photochemists. The style is clear and readable and one cannot fail to acquire a stimulating point of view on many problems. The book is divided into five chapters. The Introductory Chapter rovers the general laws governing light absorption as well as an elementary treatment of certain phases of spectroscopy, thus providink the reader with a hasty survey of the action +radiation on atoms and molecules. The following chapters deal with The Primary Light Process; Secondary Chemical Processes, Chain Reactions; The Dependence of the Quantum Yield on Temperature and Wave-Length; and Experimental Methods. A very short bibliography is appended The author has accepted the Bohr atom as being adequate for a qualitative description of many processes of interest to the photachemist and introduces the viewpoint of Franck in discussing light absorption by molecules. No mention is made of the subject of wave mechanics either as applied t o spectroscopy or as applied to collision processes. I n some respects the inclusion of the viewpoint of the newer phases of quantum mechanics might have been desirable. The book is written essentially from the chemical side and one has the feeling that many of the intimate pictures of reaction mechanism, particularly as regards reaction
