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after, in various chapters, cotton receives detailed consideration as regards surface potential phenomena, the recognition and measurement of damage, and mercerixation. No less exhaustive is the treatment given t o the animal fibers: after discussing the behavior of wool and silk as amphoteric colloids, separate chapters are devoted to a n examination of the influence of disulfide bond reactivity on the properties and processing of ~ o oand l to the scientific aspects of felting and milling. With the preceding information as basis, the colloid chemistry of dyes and dyeing processes and the behavior of dyes on the fiber are discussed in three excellent chapters, in which the author makes use of his specialized knowledge. Finally, there are three chapters devoted to the colloid chemistry of soaps, detergents, wetting agents, and sizing materials. The book is beautifully produced, is well illustrated, and has an excellent bibliography a t the end of each chapter. Dr. Talk6 is to be congratulated on this important contribution t o the advancement of the science of textile materials and processes. J. B. SPEAKMAS. Principles oj” Chemical Engineering. By W.H. WALKER, W. K. LEWIS,W.H. IIcADAbfs, A N D E. K. GILLIIAKD. 23.3 x 16 cm.; ix 749 pp. 3rd edition. New York: McGraw-Hill Book Company, Inc., 1937. Price: $5.50. The third edition of this book has been considerably revised and much of it rewritten. Many changes have been made in the chapters on flow of fluids, floiv of heat, and those having t o do with diffusional processes, including the ne1vt.r theoretical developments and data and fundamental constants. All of the material is treated from the quantitative or matheniatical standpoint, a s was done in the previous editions. Though the presentation of material is usually clear, the treatment may cause some difficulties for students beginning the subject of the chemical engineering unit operations. I t is to be noted that a fourth author has been added to the group writing earlier editions. This is one of the excellent standard texts on chemical engineering principles. CHARLES A. IIAXX.
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Numerical Data on Radioacticity . &VuclearPhysics. Transmutations. Xeutrons. Positrons. By I. JOLIOT-CURIE, B. GRINBERG, R. J. WALEN. Excerpt from Annual Tables of Constants. 57 pp. Paris: Gauthier-Villars, 1931-36. This represents the data in the field of radioactivity and nuclear physics published during the period 1931 t o 1936. Saturally most of the space is devoted t o the new 1 to 30, nuclear transmutations and to artificial radioactivity. Of the elements XOS. only helium has not been transmuted, and only hydrogen, helium, beryllium, and chromium have not been shown to have artificial radioactive isotopes, though those for nickel and cobalt have not been positively identified. From S o . 31 t o S o . 92 only nine elements of the non-radioactive elements have not been transmuted or made radioactive. I n addition, new artificially radioactive isotopes have been produced from thorium and uranium. S. C. LIND.
