RECENT BOOKS CHEMISTRY AND You. B. S. Hopkins, University of IUinois, R. E. Davis, Lane Technical High School, Chicago, Illinois, H. R. Smilh. Lake View High School, Chicago, Illinois, M . V. McGill, Lorain High School, Lorain, Ohio, and G. M. Bradbury, Montclair High School, Montclair, New Jersey. Lyons and Carnahan, Chicago. Illinois, 1939. xii 802 pp. 264 figs. and 17 full-page marginless illustrations, one colored. 13.5 X 21 cm. $1.80. This secondary-school textbook is definitely in unit form. The authors consider the first nine of the sixteen units essential core matrrinl. All of the prinriplrs arc contained in them and illurtrative material rbrrntial to completing any of the follurin~ units. A typical unit contains a full-page survey, a group of "problems," a summary in question form, and a digest of the material covered. Each problem contains generally a few pages of text mitten in a personal conversational style; references t o readings for "pleasure and profit"; a few dramatized incidents which raise chemical questions; "putting chemistry t o work," a title for A and B groups of questions which put chemistry pupils t o work; occasionally a group of numerical problems; "research and activities," a number of suggestions for charts, visits, reports, investigations, experiments, and the like. The book is modern in its approach, rigorous in its application of the scientific method of thinking, and abounding in reference t o the social implications of the topics covered. With almost encyclopedic thoroughness it covers many fields, from allergy to zymase, but it is not a book written for a class of "the underendowed." CREMISTKYA N D YOU is a hook with sufficient material difficult enough to challenge the ability of serious-minded college preparatory pupils, or any real seeker after the principles of elementary chemistry. Electrolytic solutions are studied from the standpoint of Arrhenius, but skilfully so, the authors preparing for later development. The preferred method of representing hydrates [e. g., CUSOI.(H~O).Iis used consistently. Polar and covalence are well explained. Simplified flow-diagrams aid explanation of industrial processes. Many tabulations in the text are real study-aids to the pupil, and the notable collection of twenty-one appendices forms a condensed handbook, Cross references abound. Physiological and organic chemistry are carried beyond the range of most elementary chemistry textbooks. Many points are duplicated, probably for emphasis. The inconsistencies and errors are surprisingly few for such a long hook. The reader would wish for greater sharpness of the halftone illustrations, however. The agricultural scenes are unconvincing, for example. No review would he complete unless favorable mention was made of the seventeen full-page marginless unpaged illustrations in which better detail is shown. Five able intemreters converze on the second person singular.
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TIIEORETICAL QUALITATNEANALYSIS. I. H. Reedy, Associate Professor of Analytical Chemistry, University of Illinois. McGraw-Hill Book Company, Inc., New York City, 1938. ia f 451 pp. 13.5 X 20.5 cm. $3.00. I n this hook the author aims t o supply the beginner with the theoretical and factual background essential to intelligent work in analytical chemistry. I n the theoretical section, which constitutes slightly more than one-third of the hwk, the usual topics are dealt with: the nature of solutions, the colloidal state, equilibrium and the mass law, ionization, applications of the ionic theory (including the precipitation and solution of sulfides),
amphoteric hydroxides and sulfides, complex ions, hydrolysis, reactions and equations (including oxidation and reduction). The descriptive portion is subdivided according t o the conventional groupingsof cations and anions, with additional chapters on dry reactions and on systematic analysis. These subjects are discllssed in a lively and unstilted manner, with occasional flashes of humor, and the author shows considerable insight into the difficulties experienced by the average student. The approach to most of the topics enumerated is along strictly traditional paths. With regard to the apparently still troublesome question of partial vs. complete ionization of strong electrolytes, the author states in his preface, "An attempt has been made t o present both sides in an unbiased way, so that the student will not carry over into later courses an undue prejudice in favor of either theory." I t seems to the reviewer, however, that the treatment of the newer concept is something less than adequate. The essential features of the theory of complete ionization are stated, it is true, together with some of the arguments in its favor. The author then refers t o the activity "theory," and cites data on the activity coefficient, y, of potassium chloride, as calculated hy different observers using different methods, t o show that "the agreement is no better than in the values for o on the basis of incomplete ionization." As a matter of fact, so far as the figures cited are concerned, the agreement among the y values is not nearly so good as between the two values of a obtained, respectively, from conductance and from freezing-point data. But the author neglects t o emphasize the fact that the divergence of these y values must, in the nature of the case, arise from experimental errors alone, while the uncertainty as to the "true" value of a has its origin in a fundamental difficulty with regard to the definition of the degree of dissociation of a strong electrolyte. In subsequent applications and problems, the older concept is retained, for the most part. Several of the topics are dealt with more intensively than is usual in textbooks of qualitative analysis. The chapter on the colloidal state and mechanics of precipitation, for example, includes an unusually thorough discussion of the technic of handling precipitates which tend t o become collaidal. A fresh viemoint is broueht to bear u m n the discussion of reactions and equations; morr stress is placed upon the identification of products than upon thc mere halanving of rquntions, and a clnssifiration of the more impurtarn typrc of reaction is a useful feature of this chapter. The descriptive portion of the book contains a large amount of detailed infohation, with special emphasis upon those reactions which are most useful for the identification of the ions. This section includes, as an unusual feature, the critical discussion of various methods of analysis, where such alternative methods are in use. Thus, for example, four distinct methods of analysis of the aluminum-zinc group are described. The book is evidently not intended to serve as a laboratory manual, however, and does not include specific directions either for preliminary experiments or for analytical procedure. Numerous exercises are given a t the end of each chapter. While those included in the theoretical section are mainly of the conventional type, those which follow the descriptive chapters are exceptionally varied and interesting, and call for careful thinking by the student. The reader who seeks an exposition of modern developments will be disappointed a t the absence of any discussion of atomic structure, of the electronic nature of valence, of the Werner co6rdination theory, or of the Br#nsted concept of acidity. The omission of the first of these topics is perhaps responsible for a rather surprising treatment of the difference between free elements and ions (page 56). from which the student could hardly avoid reaching the conclusion that the hydration of an ion is
