NEW BOOKS
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NEW BOOKS The Anodic Ozidation of Aluminum and its Alloys. By A. JENNY.Translated by Winifred Lewis. 6 x 9 in.; vi 231 pp.; 107 figures; 36 tables. New York: The Chemical Publishing Company, Inc., 1940. Price: $6.50. The anode reactions of aluminum have been studied more extensively and in greater detail than those of any other single metal. Dr. Jenny has packed into this small volume some of the pertinent facts relating to the commercial processes which make use of the reactions taking place a t an aluminum anode. Starting with simple electrochemistry and the chemical properties of aluminum, the author builds a foundation for his discussion of valve action and the formation of the condenser type of film. Then follows a description of the production and properties of the thick anodic oxide films which are used commercially for their protective and decorative properties. All the steps employed in the production of anodic oxide coatings are discussed to some extent, such as preliminary surface treatment and after-treatments which include sealing, dyeing, and impregnation with photosensitive compounds. After weighing the good and bad features presented for each electrolyte and the coatings produced therein, one wonders why so much space was devoted to the operating characteristics of the oxalic acid electrolyte and so little space given to the sulfuric acid electrolyte, which is the one with the greatest commercial usage. Lewis has given us a good translation of the original German text. I n only a few instances does the English translation differ from the German. The translator has added four or five footnotes to increase the single literature reference included in the original German text to the number of three or four in the translation. Unfortunately, most of the references in the text give the name of the author only and the reader must himself search for the source of publication. I n a number of instances, data from the unpublished work of Siemens and Halske A. G. are included. A list of British patents dealing with oxide coatings on aluminum has been added to the translation, but the reference to British and American developments in the text is scarcely commensurate with the pioneering part they have played in this art. For the most part, the book is easy to read and has many interesting observations not found elsewhere. I t has been written more from the practical than the theoretical standpoint and is recommended to those interested in the commercial production of aluminum oxide coatings. R. B. MASON.
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Waves. By C. A. COULSON.5 x 71 in.; viii 156 pp.; 29 figures. London: Oliver and Boyd, 1941. New York: Interscience Publishers, Inc., 1941. Price: $1.50. This little book, which is one of the series of University Mathematical Texts, gives a concise account of the common types of nave motion. Starting with the fundamental equation of wave motion, as many problems as possible are discussed: waves on strings, waves in membranes, waves in bars and springs, waves in liquids, sound waves, and electrical waves. While all of these topics have been discussed by theoretical physicists many times, still the present compilation is noteworthy for its clarity of presentation and i t s conciseness. GEO. GLOCKLER. Grundlagen und Ergebnisse der Ultraschalljorschung. By E ~ O HIEDEMANB. N 61 x 91 in.; ix f 287 pp.; 232 figures; 1 color plate. Berlin: Walter de Gruyter and Co., 1939. Price: 24 RM. (about 88.50). This book presents by far the most thorough and complete review of the whole
