S E W BOOKS
509
matter on an enormous scale. Severtheless, in spite of the impossibility of obtaining exact knowledge of current Russian synthetic rubber practice, this section probably enables one to form a reasonable estimate of the present situation. The third p a r t is devoted t o polymerization in general, including theoretical and experimental discussions of thermopolymerization, emulsion polymerization, as practiced in the United States, England, and Germany, and sodium polycondensation, as used i n the U.S.S.R. The fourth part deals with the physicochemical properties of the polymer, including polymer structure and methods for its investigation. chemical properties, and an excellent survey of the theoretical and practical aspects of the properties of high-polymer solutions. -4lthough the book contains nearly six hundred references, it is by no means a mere literature compilation. The authors have presented a careful evaluation of a n enormous amount of material, most of u hich is not readily available t o the average chemist. Actually the book has a much wider scope than is indicated by its title, which hardly does justice t o the subject matter. It can be recommended strongly t o all chemists and engineers interested in polymerization in general, or in butadiene production. Only one error was noted by the reviewer: the statement on page 215, t h a t a numberaverage molecular weight is given by light-scattering measurements, is incorrect. E. J. MEEHAN. The Theory of the Photographic Process. By C . E. I ~ E X X E MEES. T H 1124 pp. New York: The Macmillan Company, 1934. Price: $12.00. I n its more than one thousand pages, this book contains a wealth of interesting and stimulating facts. Rather than being an intensive exposition of the theories of the basic photographic reactions, as its title suggests, this book is nearly a n encyclopedia of the facts and related theories of the photographic industry. As a result i t touches on such unrelated subjects as the physics of crystals, the synthesis of dyes, statistical analysis of skewed distributions, and the dietary habits of rabbits. T o the reviewer, it appears that the technological and organochemical aspects of the subject are treated somewhat more comprehensively than its theoretical (physical and physicochemical) phases. I n general the approach t o the several theoretical fields is historical rather than critical. This, the historical approach, adds somewhat t o the complexity of a n inherently complicated subject. I n a few cases some minor faults might be found with the interpretation of facts, but in a n encyclopedic work of this sort one marvels a t the general accuracy rather than being surprised a t a few slips. I t is somewhat surprising that the general subject of color photography is not treated in this book (except f o r a n incidental mention of the Kodachrome process on pages 393-8). Photographic processes which do not use silver halides are not mentioned. The use of photographic emulsions for recording x-rays or radioactive rays is not discussed. I n the preface, the author apologizes for omitting a detailed treatment of emulsion-making, on the grounds t h a t the greater part of such information is still confidential. The author’s style is in general simple and direct. The value of the book is increased by numerous references t o the original literature. The book is clearly printed on opaque, glazed paper and is well illustrated in the diagrams and reproductions of photographs.
ROBERTLIVINQSTON.
