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and T. H . HAZLEHORST.Third revised edition. Qtcalitatiw A n a l y s i s . By H . V. ASDERSOX 6+ x 9+ in.; xi 266 p.; 11 figures; 21 tables. New York: Prentice-Hall, Inc., 1941. Price: ftrade) $3.70; (school) $2.75. The presentation of the principles of the science of chemistry is the same as in the previous edition, but certain changes have been made. The first seven chapters deal with atomic theory and the properties of solutions and precipitates, including an up-to-date treatment of acids and bases and of oxidation-reduction. It is peculiar to find in a modern book the percentage of ionization of strong electrolytes given in terms of the classical measurements of the conductance (Appendix 111, page 251). The order of the solubilities of the metal sulfides (page 41 ff.) is entirely wrong, as the authors disregard hydrolysis. For the same reason the calculation of the sulfide concentration in an ammonium sulfide solution is greatly in error. The tevt is somewhat ambiguous a t certain spots. For example, the statement (page 56) “the ions in solution move rapidly, with velocities measured in miles per second; but they do not get f3r in a short time because they encounter a considerable resistance from water molecules, with which they are constantly colliding.” I t is hard for a reilder to understand the following experiment (page 63): “If water is run through slayer of finely divided (colloidal) carbon, the filtrate is basic because the hydrogen ions of the water have been selectively adsorbed and the hydroxy! ions remaining give a basic reaction.” The revieJver would like to have a sample of pure carbon which has the above property. The last seven chapters deal with the classical scheme of qualitative inorganic analysis. The appendix contnins several useful tables. I . M . KOLTHOFF.
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The Physical Emmination of Metals. l’ol. I I . Electrical Methods. By BRUCECHALMERS 274 pp.; 101 figures; 11 tables. and A . G. Qi-ARRELLFirst edition. 53 x S t in.; viii S e w York: Longmans, Green and Company, 1941. Price: $6.00. This book shows how the so-c,alled electrical methods are used for many types of examination of metals. The applications and the theory involved are clearly explained and the authors seem to have covered this important subject well. All the different electrical schemes used for studying metals are discussed in detail. The book is well illustrated, also, and is recommended to those interested in testing metals for commercial applications. However, the commercial applications of the many methods are not overstressed, because the authors are physicists and appear to be more interested in the mechanism involved in the theories of the various tests. The types of tests discussed and illustrated are the following: I. Magnetic methods, including induction schemes, magnetic powder, permeameters, etc. (70 pages) ; 11. Electrical methods, including resistants, bridges, thermometry, capacity, etc. (52 pages); 111. X-ray diffraction methods (66 pages); IV. Diffraction of electrons (44 pages); V. Electron microscopes (1spages); VI. Radiography mrthods (12 pages). There is also an appendix of ten pages on electrolytic polishing, crystal structure of metals, crystal systems, etc., and a good indes. The book is written in a clear style and is recommended to those whoae interests lie in the field of testing of metals. The average scientist and engineer will find i t interesting and instructive. The authors are to be congratulated on their summary of these important methods of testing, especially at this time. RALPHL. DOWDELL.
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