V ~ L8, . No. 11
RECENT BOOKS
metallic conduction only, a fact which should have been stated. On page 63, the expression "Simple" Gas Laws should have read "Ideal" or "Perfect" Gas Laws. We note that the author has chosen to include the BeattieBridgman equation of state, which though possessing certain advantages of mathematical form, contains purely empirical constants. I t is unfortunate t h a t the equation of Dieterici is omitted, for its constants have the same physical significance as those of van der Wads, and permit, from this equation alone, the calculation of the characteristic properties of the critical point. I n connection with the discussion of the Periodic Law, it is worth while to point out one notable exception in the case of the solid elements-namely the property of specific heat, which is not a periodic, but a hyperbolic function of the atomic weight. The printing and binding of the hook are excellent. I t is substantially free from typographical errors. A few instances of careless proof-reading appear in the spelling of proper names; for example, Huygen, Berkley, Bridgeman, Craghoe, Wycoff, Kirschmann, and Bohi. The book has so many desirable features that its shortcomings are insignificant in comparison. The choice of the illustrative material and the co6rdination of so heterogeneous a group of subjects in a book of this scope, give evidence of much critical and painstaking effort on the part of the author. The clarity and freshness of style exemplified in this b w k also reflect a measure of the author's enthusiasm and interest in the subject. The wide variety of excellent problems which the student is called upon t o solve, after an intelligent selection of the necessary data from the tables, indicates the thoroughness of mastery of the subject necessary for their solution. The author deserves much credit for producing so splendid a text for the beginning course in physical T. F. BUEH~EK chemistry. U~rvnasrrvon Aauom TUCSON. ARIZONA
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An Introduction to the Principles of Physical Chemistry. 0. MAASSand E. W. R. STEACIE,McGill University. First edition, John Wiley &Sous, Inc., New York 269 pp. 62 Figs. City, 1931. vii 15 X 23 cm. $2.75.
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As the authors state in the preface, the book is intended for use as a text for a first course in physical chemistry for chemists, chemical engineers, and students intending to enter medicine or the biological sciences. The authors suggest that in the case of chemists the course be taken a t the earliest possible stage of training. The viewpoint of the text is that the basic principles of theoretical chemistry are most important-an idea which is brought out in a well-written first chapter. On the whole, the authors have lived up to this chapter. The first ten chapters are well presented and form a good foundation for more advanced courses in physical chemistry. Chapters X I and XI11 were somewhat disappointing to the reviewer. I n Chapter X I the law of mass action is derived from kinetic considerations and the assumptions involved are discussed. The statement is then made (pages 185 and 186) that ". . .it is also possible to derive it" (the mass law) "from energy considerations. In such a derivation it is customary t o use a fictitious 'active mass' in place of the real concentration and thus t o appear t o avoid the inaccuracies of the mass law." This statement is unfortunate, for it is not the energy relations or the mass law which is inaccurate. The difficulty arises from the fact that the free energy changes cannot be accurately related to the concentrations. I n explaining, a n page 225. the fall in specific conductance of sodium chloride solutions with dilution the authors state "Presumably there are more ions in two liters of the dilute solution than in one liter of the concentrated solution. This can best be explained by assuming that the dissociation of sodium chloride is not The statement is one complete..
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JOURNAL OF CHEMICAL EDUCATION
which the student will have t o unlearn later, and to a certain extent the authors attempt t o correct themselves on pages 232 and 233. The whale treatment would be considerably improved if the authors would point out that the mobilit ~ e sof the ions change with the ionic concentration, making i t impossible t o determine the degree of ionization of strong electrolytes from the simple X/Xa ratio. On page 239 the authors write "With the development of the theory of electrolytic dissmiation, i t w a s soon realized that the fundamental property of an acid is its ability t o dissociate in aqueous
solution to give a larger concentration of hydrogen ions than that which exists in pure water alone." A more general, more fundamental and more fruitful definition is that an acid is a substance which gives up a proton. In justice to t h e authors i t should he said that the same faults exist in most of the other introductory tents on theoretical chemistry. The reviewer recommends this book and would like to see i t used as a basis for a second course in chemistry. MARTINK m ~ n m ~ c K JR. . UNrVBRSlTY 0. P B N N I V L Y A N I A
P ~ I L A D B L P H I * , PBNN*.
