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?JEW BOOKS
simple rotating- and oscillating-crystal methods, and detailed treatments of the increasingly important moving-film methods-especially the Weissenberg, Sauter, Schiebold, and de Jong-Bouman methods. The latter have been available only in the original literature in the past. The treatment throughout is based on the reciprocal lattice, which is presented very completely. A very escellent chapter on precision in the determination of lattice constants deserves special mention. Finally, it gives many experimental details which have never appeared in the literature. The book requires little background, inasmuch as such subjects as elementary lattice theory, x-ray diffraction, space groups, etc. have been treated in a gradual manner. Where possible the author presents ideas requiring space geometry, first in terms of a n example in a plane. Another excellent) feature is the inclusion of all the intermediate steps i n the mathematical derivations. In the case of crystallographic proofs customarily given in vector algebra, alternate proofs are presented by geometrical and algebraic methods. The typography of the book is excellent, and the drawings are the finest the reviewer has ever seen in books in this field. I n spite of the large amount of mathematical detail it appears to be remarkably free from errors. I t is to be recommended without reservation whatsoever, and workers in the fields of x-ray diffraction and crystallography will find i t a “must” for their book shelves. HAROLD P. KLUG.
contributions to Chemical Education. Number One. Acids and Bases. .4 Collection of W . C. JOHNSON, H . N . ALYEA, Papers by N.F. HALL,H . T. BRISCOE,L. P. HAMMMETT, 1.P. MCREYNOLDS, T. H . HAZLEHURST, ANn W . F. LUDER.5 x 8 in.; vii 103 pp. Easton, Pennsylvania: The Journal of Chemical Education, 1941. Price: $1.00. The first four articles in this booklet are papers presented in the symposium arranged by the Division of Chemical Education a t the Spring Meeting of the American Chemcal Society in 1939, in which the modern definitions and conceptions of acids and bases were discussed. These papers and a number of other articles on the same subject (with the esception of one) which are collected in the above booklet have been published in the Journal of Chemical Education. Several of the papers deal with the methods of teaching the modern conceptions and theories of acidity and basicity. One cannot but feel t h a t the answer to the question whether the newer concepts and theories should be taught in elementary courses is not solely determined by the background of the average student, who can assimilate new ideas if clearly presented. ‘Po a large extent the answer is determined by the ability of the teacher to familiarize himself well enough with the new conceptions so that he can present them as a logical outgrowth of older ideas. L. P. Hammett, who has made valuable and original contributions to the subject of acidity, expresses himself as follows on this score (page 25): “Of course, the new theory is difficult to those of us trained in the older theory, but the difficulties me meet do not exist for students who have nevzr met the older theory. Even now my own tongue stumbles over the new terminology, while it slips glibly off the lips of my students, . . . . . ’ I . The other papers in the series deal with general discussions of the behavior of acids and bases in water, amphiprotic, and aprotic solvents. I t has been a happy idea to incorporate the report of the Committee on Somenclature of Acids and Bsses, headed by H. N. Alyea. All the papers are well written and thought stimulating. The editor, S .W. Rakestraw, deserves praise for havingmade available to teachers, students, and all chemists interested in the progress of their science this attractive looking booklet. I . M.KOLTHOFF.
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Contributions to Chemical Education. hrumber Two. The Polarographic Method of Analysis. By 0 . H . Muller. 5 x 8 i n . ; vi 113 pp. Easton, Pennsylvania: The Journal of Chemical Education, 1941. Price: $1.00. This booklet contains a series of papers which have been published in the Journal of
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