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NEW BOOKS
book covers a good deal of the same ground as my earlier book, The Dynamical Theory of Gases, but i t is covered in a simpler and more physical manner. Primarily, I have kept before me the physicist’s need for clearness and directness of treatment rather than the mathematician’s need for rigorous general proofs. This does not mean that many subjects will not be found treated in the same way-and often in the same words-in the two books; I have tried t o retain all that was of physical interest in the old book, while discarding much of which the interest was mainly mathematical.” I think that the author is t o be warmly congratulated on the successful achievement of his purposes and on doing this in a book of only three hundred pages. This book strikes me as being an ideal introduction t o the kinetic theory of gases and as such will no doubt be welcomed by all teachers of this subject. A number of appendices, dealing with the H-theorem, the normal partition of energy, and the law of distribution of coordinates and including tables for numerical calculations and a list of certain integrals involving exponentials, add t o the value and completeness of the book. The index of subjects and the index of names contribute much to the usefulness of the text.
F. H. MACDOUGALL. Chemical Species. By JEAN T I M M E R X b N S . Translated by Ralph E. Oesper. vi 177 pp.; 16 fig. New York: The Chemical Publishing Company, 1940. Price: $4.00. Chemists who are especially interested in some phase of the numerical evaluation of the physical properties of pure compounds may find this volume to be of value aa a handbook. It consists of twenty-six short chapters, and is divided into four parts. Although the first of these parts begins and ends with a rather philosophical discussion of the basic ideas underlying the science of chemistry, i t is devoted chiefly t o those aspects of heterogeneous equilibria which are directly related either t o the purification of compounds or to the measurement of their physical properties. The common methods of purifying compounds as well as the several criteria of purity are discussed in the second part. The third part contains a straightforward b u t elementary presentation of the theory of measurement and of errors. Part four, while the shortest, is possibly the most interesting and unusual section of the hook. I t s contents are adequately indicated by its descriptive title: “The Way to Find in the Literature the Best Method of Purification and the Most Probable Value of the Constants of Pure Materials. Examples and Applications.” There is no index, and the table of contents contains only chapter headings. While the book is carefully and clearly written and contains much of general interest, i t must be admitted that most of the material presented in i t is now available i n greater detail in a number of well-known texts and monographs. The reviewer cannot avoid the conclusion that this work must have been of much greater value in 1928,when its first (French) edition appeared, than i t is now. ROBERT LIVINGSTON.
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