112 REVIEWS REVIEWS. TEXTBOOK OF QUANTITATIVE CHEMICAL ANALYSIS. By A. C. CUMMING, D.Sc., London: Gurney and Jackson; Edinburgh: Oliver In the production of a Textbook of Analytical Chemistry, the first and perhaps not the least of the difficulties confronting the author is to decide precisely for what class of readers the book is intended. It is obvious that one and the same textbook cannot advantageously be addressed to the elementary student, the advanced student, and the professional analyst.In their preface the authors state that this work (a review of the first edition haps already appeared-hALYsT, 1914, 39, 240) “is intended primarily for Uni- versity and college students,” and they add that “in planning it we have not over- looked the fact that those who study chemistry as a srubsidiary subject usually devote so short a time to it that it is impossible for them to cover any comprehensive course; and that, even when chemistry is one of the main subjects of study, the student as a rule has a strictly limited time for laboratory work.” They also add that they have dealt with volumetric analysis before gravimetric analysis, because “ the educative value of volumetric methods is probably greater than that of any other branch of analysis; and we are of opinion that a student should receive a thorough training in volumetric analysis even if the time remaining at his disposal permits of but little gravimetric work.” It is unhappily true that numbers of students, “ even when chemistry is one of the main subjects of study,” are taught in such a superficial manner that the instruction they receive is neither useful from the educational, nor, indeed, from any other point of view; and it is rather a pity that two authors of the standing of Dr.Cumming and Dr. Kay, in catering for such students, should appear to countenance such a class of teaching. It is this which has been partly responsible for the low esteem in which analytical chemistry has been so often held in the past, and for the widespread belief that every general practitioner is qualified to practise toxicology, to say nothing of general chemical analysis, and that every medical officer of health is an authority on the chemical composition and analysis of all the products coming within the purview of the Sale of Food and Drugs Acts.The uncertainty as to the audience to whom the authors are addressing them- selves renders a critical review of the book somewhat difficult. This will be clear and S. A. KAY, D.Sc. and Boyd. Second edition, 1916. Price 9s. net.REVIEWS 113 when it is pointed out that, whilst the book contains much matter obviously in- tended for the absolute beginner, it deals with the analysis of ores and alloys, the complete analysis of superphosphate manure, technical gas analysis, water analysis, quantitative organic analysis, and the determination of molecular weights.In the section devoted to volumetric analysis, which is, according to the authors, intended for elementary students who may not have time to study more than the rudiments of gravimetric analysis, one finds methods for the determination of the iron in natural silicates and slags, and the determinaiion of iron and chromium in chrome iron ore.In the section devoted to systematic quantitative analysis, the authors have retained the alphabetical system, which, so far as the writer can see, does not present any advantage, and which is surely less satisfactory from the point of view of the student than an arrangement baped upon chemical relationships.Thus, barium and calcium are separated from one another by bismuth, boron, bromine, and cadmium ; whilst strontium, which can scarcely be regarded as a rare element, is entirely omitted. Thus, under the heading “nitrate the student is instructed to apply the brucine test, and, if nitrate is present, to estimate it by the copper-zinc couple, no reference being made to Crum’s method, which is by far the most accurate when the amount of nitrate present exceeds a very small amount.Under the heading “ nitrite ” the authors refer to “ Llosvay’s reagent.” It should be pointed out that this method is due to Peter Griess, Llosvay having merely recommended the substitution of acetic acid for a mineral acid.The correct descrip- tion is therefore the Griess-Llosvay reagent. In recommending the ignition of the water solids after weighing “in order to obtain an idea of the amount of organic matter present in the residue,” the student might well have been warned that, given much nitrate, there would be little charring even in the presence of a considerable amount of organic matter.In referring to the bacteriological examination of water, the authors remark : ‘‘ It is usually necessary to examine the water more especially for pathogenic bac- teria.” As a matter of fact, such an examination is but rarely made, since the dis- covery of definitely pathogenic bacteria would be the equivalent of locking the stable door after the horse had been stolen.The student should be taught that what is of the greatest importance is to establish either by chemical or by bacteriological means-or, better still, by both-the presence or absence of polluting organic matter. In the former case the water may be described as potentially, if not actually, dangerous, and those who me accustomed to use it may be warned in due time.Among the many excellent features of this book are the sections devoted to elementary electrolytic processes and to the estimation of traces of certain elements by colorimetric methods. This latter section might well have been extended to include nickel. It may be noted in this connection that no reference is made to the important dimethyl-glyoxime or a-benzil dioxime methods, although in another part of the book the “ cupferron ” method for the estimation of iron is described in detail.The authors give a prominent position to a reference to special British labora- The section devoted to water analysis is open to some oritkcism.114 REVIEWS tory glass, but no reference is made to the work of the Joint Committee of the Insti- tute of Chemistry and of the Society of Public Analysts and Other Analytical Chemists in publishing and circulating standards of purity for chemical reagents.The descriptions of processes are for the most part clear and concise, and the underlying principles are well explained. The book is well printed, well illustrated, and is supplied with an adequate index. There is also an appendix containing a good deal of useful information. It may safely be recommended to serious students of analytical chemistry; the others do not matter.A. CHASTON CHAPMAN. THE SCIENTISTS’ REFERENCE BOOK AND DIARY, 1917. J. Woolley, Sons and Co., This little reference book and diary is bound in leather with rounded corners, the diary and pencil being detachable. The Reference Book, consisting of some 130 pages, comprises tables, data, and constants, dealing with nearly 300 distinct subjects.Thus, under the letter P, for example, is included concise information and tabular matter dealing with such diverse subjects as parasitic diseases, the perihelion, periscopic lenses, composition of pewter, physical constants of the elements, human physiology, the planets, popu- lation of countries, postal information, potential energy, the poundal, prisms, pro- teids, and pyramids. The book is well printed, and the facts so far as they have been tested are accurate and well selected. As a handy little work of reference, it will be found to contain much that is often sought in vain in much larger volumes, while it should prove of distinct use to anyone searching for a diary and reference library combined in one small cover. Manchester. Price 2s. 6d. H. F. E. HULTON