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The accomplishments of this new instrument are already astounding, but as its use becomes more extended no one can foresee the developments that will result, especially when the instrument is made readily accessible through simplification and reduction in cost. Its thorough exposition by such competent authorities adds t o the contributions they have already made in its development and introduction. S. C. LIND.
Electronic Physics. By L. GRANTHECTOR,HERBERT9. LEIN, A N D CLIFFORDE . SCOGTEN'. 355 pp. Philadelphia, Pa.: The Blakiston Company, 1943. Price: $3.75. This text is an introduction for beginners to the simpler phenomena of electricity and magnetism. Although i t appears too elementary for college use, i t is stated t o have been used in freshman and sophomore college courses as well as in training courses for pilots, students in the Signal Corps radio classes, and in some high school classes. It is unusually well and prolifically illustrated with two-color line drawings, black and red, which enliven the appearance and help t o clarify the illustrations. S. C. LIND. Electrical Counting. With Special Reference to Counting Alpha and Beta Particles. By W. B. LEWIS. 14 x 22 cm.; vii 144 pp.; 73 fig. London: Cambridge University Press, 1912. Price: $2.50. This book contains, in admirably compact form, a large amount of useful information for the experimental nuclear chemist or physicist. Its most striking characteristic is the concise style which the author employs to pack so much authoritative knowledge into so few pages. In the literature on the subject of counting, one might-and often has-read several times the volume of the present work without finding as much factual information as Dr. Lewis has here put a t the reader's fingertips. After a brief statement of the physical basis of the electrical method, the author takes up the design and operation of the various parts of a counting system in order: the ion chamber, the amplifier, and the recording devices, including scaling and mixing circuits. Each of these subjects is discussed with a nice balance between theory and practical details. A chapter is devoted to the principle of inverse feedback and to voltage stabilizers. The description of circuits, chiefly in terms of British makes of vacuum tubes and other parts, imposes a minor limitation on its usefulness to American workers. The chapter on Geiger-Muller counters includes a n excellent review of the theories of counter operation and no less than seven varieties of extinguishing circuits. Many readers will welcome the inclusion, in t,he chapter on statistics, of Bateman's derivation of the Poisson formula for random distribution and the corollary square-root error relation. The writer noted one or two obvious crrors in this part of the text. On page 115,the chance that no particles arrive in zero time, Wo(O),is stated to be zero, whereas, being certain, this chance actually has a probability of unity. A concise but complete account of the determination of the ranges of alpha-particles. with all the attendant corrections and an illustrative numerical example, occupies the final chapter and an appendix. A list of eighty-two citations to the literature covers only articles published before the war. The writer feels that this little book is a most useful addition to his library, and has no hesitation in recommending i t as the best book on counting he has yet seen. D. E . HULL.
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Proteins, Amino Acids and Peptides as Polar and Non-Polar Ions. By EDWINJ. COHN AND JOHN T. EDSALL. 686 pp.; 116 fig. Reinhold Publishing Corporation, New York. Price: 813.50. This book was written by eight collaborators, E. J. Cohn, J. T . Edsall, J. D. Ferry, J. G. Kirkwood, J. W. Mehl, H. Mueller, J. L. Oncley, and G . Scatcbard. Of these eight, Edsall contributed the greatest number of pages.
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The book is well printed, and the figures are large and easily understood. I t is remarkably free from typographical errors and is written in clear and explicit language. Part one, which occupies nearly half of the book, deals almost exclusively with the electrochemistry of amino acids and peptides in solution. Part two is devoted to protein chemistry, a large portion of which is the electrochemistry of protein solutions. The thesis of the book is thus to a great extent the electrochemistry of solutions I t is curious, in view of this, that the discussion of electrophoresis is confined t o a short chapter, is entirely of a general nature, and has nothing about proteins or amino acids in i t . As will be gathered from these remarks, this book is not a general treatment of proteins or even of the physical chemistry of these substances, but is strictly limited in its scope. I t is essentially a progress report from the Harvard Laboratories, supplemented by such references in the literature as bear upon the work of this group. Such a report should prove of great value t o protein chemists. In a book so free from errors, i t is surprising t o see on page 196 and again on page 584, the general statement that the activities of a substance in two phases in equilibrium are equal t o eacli other. The authors even go so far as to cite Lewis and Randall in support of this statement! HENRYB. BULL.
