RECENT BOOKS VOLUMETRIC ANALYSIS. A . 3. Berry, M.A.. Fellow of Downing College and University Lecturer in Chemistry, Cambridge Fifth edition. Cambridge University Press, London, 1939. (The Macmillan Company, New York City). vii 196 pp. 9 figs. 14 X 21.5 cm. $2.50. As the reader would naturally anticipate, this little book on volumetric analysis by Professor Berry, whose scholarly achievements have long since been recognized, presents some very attractive features. It differs from the typical analytical text of the present day, however, in so far as it is comparatively free from theoretical matter. I n truth, underlying principles are given exposition in'connection with certain processes, and these expositions are t o be found here and there among the pages; yet there is no apparent attempt t o build a continuous framework of physical chemistry. The foregoing statement is not to he taken as unfavorable criticism: the author has thus been able t o bring into small compass a great variety of methods; consequently the student may proceed from the general t o the particular, and, as is more important, awake to an appreciation of the immense scientific and utilitarian value of volumetric procedurespedagogic results that can hardly be expected to accrue from the perusal of a small manual that is but a collection of a few particular cases. As the author says in his preface t o the current edition, the volume is intended to be one of intermediate scope. It is composed of fifteen chapters, some tabulated data, and an index. The 6rst chapter is introductory in its nature. The next seven (Chapters I1 t o VIII, inclusive) deal with the ordinary volumetric processes: namely, those that depend upon oxidations (and reductions), precipitations, and neutralizations. The remaining chapters embady: (IX) the theory of indicators and hydrogenion concentration. (X) unclassified volumetric determinations, (XI) special applications of volumetric methods, (XII) actual examples (volumetric only), (XIII) simple gravimetric determinations, (XIV) modern developments in volumetric analysis. and (XV) analysis of gases. I n the reviewer's opinion, the work now under consideration, like other chemical textbooks, exhibits some shortcomings. A few of these, taken haphazardly, will he mentioned. After discussing normal solutions a t length (pages 4-6). the author does not direct that normality factors be employed in calculating the results of analysis. On the contrary, he introduces the equivalent weights of various substances,, and many of these equivalents are unnecessary. I n giving the accuracy of ordinary pipets and burets a s being within about 0.5 per gent. (page 10). he assumes a goad deal of responsibility, for there is no way of judging, except by calibration, the graduation errors of any volumetric instrument. I n fact, one would have t o examine many pieces of apparatus in order t o feel justified in making any such assertion. Hence it is unfortunate that detailed instructions are not given for testing these measuring devices. (The excellent work by V. Statt, a t the National Physical Laboratory, might well have been referred to.) Directions are often given t o the effect that, after dissolving the sample, the operator make the solution up to a definite volume and then take aliquot portions for the actual determinations. Though this modus operand; unquestionably bas its advantages, it is not always feasible; especially when the constituent sought represents a small percentage only of the material that is being subjected t o analysis. The apparatus depicted an page 54 (Figure 3) far use in determining the available oxygen in manganese dioxide (manganese ore) seems bath antiquated and awkward in comparison with the simple, yet elegant, contrivance of F. A. Goo& and J. T. Norton, Jr. Certain of the substances recommended for use a s primary standards -ferrous ammonium sulfate, o d i c acid, calcium carbonate (Iceland spar), for e x a m p l e a r e not lwked upon by the best anslysts as being particularly reliable. I t is surprising that any one should attempt the estimation of nitric and sulfuric acids in the presence of each other by indirect analysis, seeing that it is a
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simple problem to remove the more volatile acid hy evaporation on a steam bath; whereupon thc direct titration of the residunl .wlluric acid is in order. Thc conditmns laid down for the formation of ammonium manganese phosphate and ammonium magnesium phosphate, respectively, are not sufficiently definite (page 141), and the obtainment of good results, without better directions, would doubtless be somewhat a matter of chance. H. J. H. Fenton's method for the direct determination of sodium with the aid of dihydroxytanaric acid (pages 100-8) fail%in thc prezencc of much potassium, and ccrtlin other substances interfere more or less. It is regrettable that, in describing the estimation of ferric iron by means of titanous chloride (pages 100-1). the author did not mention the very interesting monograph by E. Knecht (with Eva Hihbert) on the multifarious applications of the salts of trivalent titanium in volumetric analysis; for, in this way, he would have established a t least one exceotion t o the rule: "A oronhet . . is not rnithout honor, save in his own country." In contrast to theabove, Berry's manual containssome unusual valumetrrc processes that are not to be found in the general run of analytical texts. Among these one notices with pleasure two ingenious methods that are original with the author: the determination of thallium in the thallous condition (page 99) and the estimation of Caro's acid, &SOs, when in admixture with perdisulfuric acid. H&O8, using vanadyl sulfate as an auxiliary reagent h a r e 173). As usual, the Cambridge University Press has produced a book that is plmsing in point of appearance. And its small sire should render it a w r y convenieut adjunct to either the classroom or the laboratory. WILLIAMM. THORNTON.JR. ~~~
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LOYOLACOLLBOB BILTlldOBB. M A R Y L A N D
GRNPUL AND INORCAN~C CIIEIIISTRY. @. 1.Durt'(rn1. F d o w . Tutor and i.ecture; in Chcmistry. Selwyn College. Cambridge. I.unnmans. Grcen and Cornoauv. . .. Ncw Yark. 1H39. x T 517 pp. 14 ~ 2 cm. 2 $2.75. A description of this book should be preceded by a few words on the English secondary schools. There are five grades, or forms. Pupils in the first three forms take a standard course consisting of general science, mathematics, Latin, French, and English. A student who then elects to specialize in science devotes a large portion of his time in the fourth and fifth forms to the study of chemistry and physics. Upon completion of the fifth form. he may seek further preparation in an optional sixth form, or may enroll directly in the university. This book is designed for students in the sixth form or in the first year of university work, and presupposes two years of secandary-school chemistry. There are probably not many American schwls where it can be used as a text. It may he used, hawever, for selected groups of freshmen or for secand-year courses in general chemistry. Every teacher of elementary chemistry could profitably use it as a reference text and teaching aid. It presents a point of view which is entirely new to American readers. The first nine chapters (two hundred sixteen pages) are devoted to theoretical chemistry-the atomic and molecular theories, stater of matter, molecular, equivalent and atomic weights, atomic structure, the periodic classification, valency, solution, velocity of reaction, law of mass action, equilibria, electrolysis, acids, bases, and salts. This portion of the book resembles our rather elementary physical chemistry texts, and is more advanced than any American freshman textbook with which the reviewer is familiar. Terms such as "molecule," "symbol," and "element" are given little or no discussion. The determination of equivalent and molecular weights is given thirty
