NEW BOOKS
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The Pine Structure of Matter. Vol. II, Part III: The Quantum Theory and Line Spectra. By C. H. DOUGLAS CLARK,D.Sc., A.R.C.S., A.I.C., D.I.C.: Assistant Lecturer in Inorganic Chemistry in the University of Leeds. 14.5 x 22.5 cm.; lxxii 184 pp. New York: John Wiley and Sons, Inc., 1938. Price: $4.50. This book constitutes the third part of the second volume of the Comprehensive Treatise on Atomic and Molecular Structure, which is in the course of publication by the author. Since i t is the stated intention t o make the separate portions of the work reasonably complete individually, we shall consider the portion under review by itself, rather than a s a part of the larger work. The scope of the text is much more restricted than might naturally be assumed from the title, being concerned primarily with the classification of the electronic states of atoms and ions by means of the vector coupling model. The discussionof multiplet structures is carefully done, and many useful diagrams and tables are included, but the reviewer feels t h a t the book leaves much to be desired as a survey of the field of line spectra. For example, the whole problem of intensities (except for the simpler selection rules) is summarily discussed in four pages (5 59), while hyperfine structures and nuclear spin angular momenta are not discussed a t all. This is probably due in part to the circumstance that the author gives no theoretical discussion beyond a brief treatment of the Sommerfeld fine-structure formula on the basis of the Bohr theory. As a consequence the whole tone of the book seems unnecessarily “old quantum theoretical.” While these limitations severely restrict the usefulness of the book for reference purposes, i t will probably be of considerable help t o those readers who wish t o learn something of the actual details of atomic energy states, but who do not wish to tackle tl, more comprehensive treatments of Sommerfeld or Grotrian, or the extensive theoretical discussion of Condon and Shortley. For the physical chemist this study will u.idoubtedly become of increasing importance in the future a s the problem of relating chemical valency to atomic states becomes clearer, since i t is not possible t o understand valency from a knowledge of the ground states, alone, of the atoms and ions. E. HILL.
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Advanced Ezperiments i n Practical Physics. By J. E. CALTHROP.22 x 15 cm.; xix 121 pp. London: Heinemann, 1938. Price: 8s.6d. It is by no means an easy task to devise a n advanced practical course for final honours students in physics that shall be both a n illustration of the principles of the subject and an adequate training in the use of the hands. Students are, one feels, too frequently presented with pieces of apparatus that require little or no setting-up in order to give the required results. In Advanced Ezperiments in Practical Physics Mr. Calthrop has overcome these difficulties to a large extent. Nearly fifty excellent experiments in properties of matter, heat, light, and electricity have been collected, and the book is to be recommended to student and teacher alike. The experiments are clearly explained with the help of 170 diagrams, and a sound balance between the older and newer branches of physical knowledge has been maintained. Where necessary, references t o original papers or more complete accounts have been given. Apart from its value a s a guide t o experimental work, the book forms in many instances an appropriate supplement to the lecture course, and students in laboratories which do not possess the whole of the equipment necessary will profit considerably from the reading of M r . Calthrop’s clearly written volume. J. T. RANDALL.
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