Recent Books Chemical Reactions and Their Equations. INGO W. D. HACKH.P. Blakiston's Son & Co., Philadelphia, Pa., 1928. Sec144 pp. 3 illustraond series. x tions. 12.4 X 18.6 cm. $2.00.
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This book is designed to aid the firstand second-year college students in writing chemical equations and working some of the simple problems based on the equations. It consists of six chapters, an appendix, and glossary. The chapter headings are: Symbols and Elements, Formulas and Compounds, Equations and Reactions Involving No Oxidation and Reduction, Equations and Reactions Involving Oxidation and Reduction, Reactions and Their Control, and Types of Chemical Reactions and Equations. The Appendix consists of (1) Solubility Table. (2) Rules for Salt Formation, (3) Key to All the Eqdations Involving Any Element and Compounds. *The index and glossary defines 99 of the commoner chemical terms. I n general, the author has fulfilled his purpose well. There is an abundance of illustrative equations and an abundance of practice material in the exercises a t the ends of the chapters. The discussion of the periodic system in the first chapter is excellent up t o the last paragraph on "atomic structure." If the student bad sufficient background t o get anything out of this paragraph he would not need so elementary a treatment of the preceding part. The previous elementary treatment is . ~ e r h -a p swhat is needed so this paragraph might just as well be left out. In Chapter I1 we find per cent composition calculated from the formula by means of the old style proportion of dots. This form is perhaps one of the most pernicious causes of confused thinking in all mathematics, and should be completely
abolished; the fractional form of proportion is much less subject t o error. On page 55 are found the terms binary and ternary compounds. These two terms are supertluous t o a knowledge of chemistry and should also be relegated to the trash heap. The student is overwhelmed with necessary terms; why burden him with those that are not needed? Chapter IV on oxidation and reduction should also have been presented from the point of view of gain and loss of electrons. This point of view is gaining in favor. Also there is too much stripping the reactions of the ions and eleme?ts-that are not oxidized and reduced. In practice the student meets the prohlem in terms of complete compounds rather than ions. It will appear that the adverse criticisms are mostly on minor points. I t may then be rightly concluded thet the book on the whole is well gotten up and serves its purpose excellently. 0. L. BRAVER STATE TEACHERS' COLLEGE, SAN JOSE,CALIEORNIA
Annual Survey of American -Chemistry. Volume In. July 1, 1927-July 1. 1928. Edited by CLARENCE J. WEST under the auspices of the Division of Chemistry and Chemical Technology of the National Research Council. Published for the National Research Council by the Chemical Catalog Co., New York, 1928. 395 pp. 13 X 21 cm. $3.00. The ~ublicationof the third volume is a strong confirmation not only of the continued need for such a resume of American research, but also positive evidence of the favorable reception that has been accorded the two previous issues. The present volume contains 46 chapters and 395 pages, which is comparable with the 49 chapters and 415 pages (in-
