766
NEW BOOKS
chemistry; S V I I , Colloid C‘hrniistry; Appendix I, 11, 111; Author Index; Subject Index. This text not only presents a ~{eell-reasonedtreatment of the main elements of classical physical chemistry but, as it seems t o the reviewer, offers the best handle, among the list of available introductory textbooks of physical chemistry, by which the student may take hold of the newer developments in the field.
EDWARD MACK,JR. Ions i n Solution. By R. W. GURKEY.206 pp.; 44 figs. Cambridge: The University Press. S e w York: The hIachlillan Company, 1936. I have seldom read a scientific book with greater pleasure and interest than I experienced in going through this small volume by Dr. Gurney. I can heartily recommend it t o the attention of my fellow physical chemists. From the most modern point of view, Dr. Gurney discusses such topics as solvation energy, the interactions of gas ions among themselves and with a metal electrode, the properties of ions in a solvent and their deposition on electrodes, the formation of double layers a t phase boundaries, the electromotive force of cells, the properties of an assembly of dipoles, the conditions restricting the coexistence of ions in a solvent, the electrochemical series, and many other phenomena of great importance to the physicist and chemist. The treatment adopted by Dr. Gurney employs only the simplest mathematics but by frequent use of diagrams (particularly potential-energy diagrams) the author is able t o give to the reader an illuminating account of the phenomena under consideration. The book should be of great interest t o all physical chemists and especially to all students of electrochemistry. Dr. Gurney announces that the ideas and methods outlined in the present book will be elaborated in a second volume. The appearance of the second volume will be awaited with great interest. F. H. ~ I a c D o u ~ a ~ ~ . Reagent Chemicals and Standards with Methods of Assaying and Testing Them. By JOSEPH ROSIN. 530 pp. S e w York: D. Van Sostrand Company, Inc., 1937. Price: $6.00. A book of this nature should be of value t o anyone who makes use of chemicals. Various examples could be quoted from the literature showing that the results of some physicochemical researches were invalidated by the fact that the authors worked with impure chemicals. One of the outstanding features of the book is that the maximum limits of impurities as indicated by the tests are specified. These tests conform, as a rule, t o the requirements of “reagent chemicals,” and are of much more importance than the assays given in many cases. If barium nitrate (p. 71) should contain, for example, less than 0.2 per cent impurities its assay should be a t least 99.8 per cent. The minimum assay given is 99 per cent, and the difference may be interpreted as due to the presence of water (for which a separate test could be made) or to inaccuracies in the quantitative procedure described. In testing reagent chemicals such assays are of much less value than the tests for impurities, unless a highly refined analytical procedure is employed. A short description of the various chemicals is given. It would be of value to add simple tests of identification as well. In general the tests are adequate, although one might in certain cases prefer simpler procedures. Calcium carbonate, for example, can be tested simply for alkalies by direct sensitive reactions for potassium and sodium. The assay for glycine can be simplified by making use of the formaldehyde reaction. In examining the primary standard silver nitrate, a test for included water should be given.
