literature references in this chapter number almost four hundred. The part closes with a short chapter, XIV, on molecular fields. The discussion here concerns modern theories. Partly because of a commendable attempt a t completeness the book lacks some of the fluencv and continuitv of thoueht which is desirable in the textbook fo; class use or sGf studv. "It -~ should be rxtremely mluahle, however, to the specialied worker in the Geld. seeking to find n conlpcndium of information available up to the time of publication. I n view of the inherent diaculties of the author's task i t is perhaps unjust to criticize him for failure to meet successfully all of the desires of all types of readers. Nevertheless, the hook seems, in certain respects, t o fulfil some of these desiderata less well than could have been hoped, even without sacrifice of the admirable brevitv and comoleteness of the treatment. The author is evidently consciously and conscientiously uncritical in his reviews of papers. This is carried t o the extent of omitting any comprehensive discussion of the assumptions involved in the derivation of the theoretical equations discussed. Since the author actually goes through the mathematical derivation of some of these equations the omission is not entirely to be Laid t o a desire for brevity. Thus the reader is often left entirely a t sea whether experimental deviations from the theoretical equation, which are often quoted in considerable detail, are due t o an inherent error in the reasoning involved in its derivation, as is occasionally the case, or due to some deviation in the substance investigated from the ideal behavior assumed in the derivation. An example which must be disturbing to the student may be mentioned. The author cites Maxwell's conclusion that the dielectric constant r is the same as the square of the index of refraction 7 extrapolated to infinite wavelength. Apparent deviations from this law are discussed frequently, and considerable use is made of these deviations. It is, however, apparently nowhere explicitly mentioned that Maxwell's theoretical conclusion is absolutely accurate, and that the deviation is solely due to the fact that both experimentally and theoretically the smooth extrapolation of r from the visible region t o infinite wavelength differs from the correct extrapolation from measurements made in the far infra-red. Largely because of this reticence of the author to discuss the assumptions underlying attempts a t theoretical developments, Chapter XI, on the Dehye theory of Polarization, and Chapter XIV, on molecular fields, are somewhat inadequate. The book is scarcely to be recommended as a text, but is without doubt an important compendium of the available scientific information in the field. I t is, therefore, a valuable reference hook. TOSEPA E. MAYER ~
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T E E FINE STR~CTUREOF MATTER. PART111, THE QUANTUM
MORY ~WD LINESPECTRA. C. H. Doudas Clavk. Universitv of Leeds. John Wiley and Sons, Inc., e e w ~ o r k ' c i t y ,1938. lxxii 185 pp. 28 figs. 13 5 X 22 cm. $4 50.
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As intimated by the title, this volume forms the third part of a series, of which Part I deals with X-rays and the structure of matter, and Part I1 with molecular polarization. The volume under review contains Chapters XV to XVIII of the series inclusive. I n the first of these c h a ~ t e r sa brief review is eiven of the different quantum effects, and mention i r made of the obaervations on the diffraction of rlcctrons. This is the only place in the volume in which rlcctron a n w i are discussed. The subject of wave mechanics is completely omitted. The sewnd chapter wntains a review of the Bohr orbital theory of the origin of line spectra, and the thud deals with the application to atomic spectra of the hypothesis of the spinning electron. The subheadings in this chapter are as follows: The Spinning Electron, Selection and Intensity Rules, The Fine Structure of Lines in Hydrogen and Ionized Helium, Multiplicity Rules and Term
Intervals, and The Ground Terms of Atoms and Ions. I n the last chapter there are discussed the magnetic energy levels of hy:sogen, the Pauli Exclusion Principle, and the application to the periodic classification of the elements and the observations on valency. A very comprehensive bibliography is attached t o each of the chapters: For those who wish t o obtain a presentation of the theory of line spectra in its simplest aspects, that is from the point of view of Bohr and Sommerfeld, this volume should prove very helpful. It is, however, a question whether it is justifiable in a discussion of the subject of spectra to omit completely any reference to the anantum mechanics interoretation of enerev levels and soectral lines, especially since thrse concepts, as developed d u r i n ~the past decade, are of such essential hpnrtance for a satisfactory interpretation of chemical valcncc and of the nature of the solid
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SEMI-MICRO QuALITATIvE ANALYSIS.Paul Arthur, Ph.D.. Assistant Professor of Analytical Chemistry, and Otto M. Smith, Ph.D.. Professor of Chemistry, both a t the Oklahoma Agricultural and Mechanical College. First Edition. McGrawHill Book Company, Inc., New York City, 1938. xi 198 pp. 10 figs. 13.5 X 20.5 cm. $2.00.
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This new volume of the International Chemical Series attempts t o give in condensed form a description of semimicro methods (Part I , twelve pages: Semimicro technic and construction of apparatus), the theory of analysis (Part 11, fifty-six pages: Important principles, Mathematical relationships, Modern theories of electrolytes, Organic compounds in analysis), the analytical procedure for the detection of cations (Part 111, seventy-one pages) and the procedure for the detection of anions (Part IV, fifteen pages). A series of problems, same special notes an analytical procedure, references t o the original literature, an sppendii with numerical tables, lists of apparatus and reagents, and an index, complete the book. I n Part I, the authors brieSy describe the essential methods of semimicro analysis, and give ingenious instructions for the conversion of ordinary equipment into microapparatus. These methods are probably quite suitable for use in small classes, hut the reviewer is somewhat skeptical as to the advisability of adopting them in the case of large groups of students, particularly if qualitative analysis is given as a portion of the freshman chemistry course, 5. e., a t a moment when so much in the standard methods is still to be learned. This is, however, a debatable point and more evidence of the kind gathered by the authors in their classes is needed. Part I1 begins with a qualitative discussion of same of the important principles of the theory of electrolytes. Derivations of most formulas are purposely left out. As a result, several paragraphs are vague and inadequate, in particular the one an amphoteric hydroxides. There follows a section in which two common types of problems are discussed: problems on the ionization of weak electrolytes and problems on solubility products, but there are no problems in which the two types are combined. The all-important relationships describ'mg the ionization of hydrogen sulfide are not used and are not even mentioned in the discussion of orincioles. The followine " section. entitled Modem Theories of Klmtrolytes, is entirely out of place in such an elementary and sketchy tmntment. The Debyc-IIuckcl thcorydocsnutlend itself to arersimplification of the kind aflrr
