RECENT BOOKS REAGENT CHEMICALS AND STANDARDS, with Methods of Assaying and Testing Them; Also the Preparation and Standardization of Volumetric Solutions and Extensive Tables of Equivalents. Joseph Rosin, Chief Chemist and Chemical Director, Merck and Company, Inc. D. Van Nostrand Company, Inc., New York City, 1937. ix 530 pp. 15 X 23 cm. $6.00 net.
analytical methods developed by many workers, tested and improved by the author from his own wide experience. FUNK T. GWCKER, Jn. No~rewssrearrU ~ ~ v ~ a s r r u ILLINOIS EVANSTON.
The author has brought t o the preparation of this reference book on standards and specifications the experience of more than twenty-five years in directing the production of reagent chemicals. During this time he has also served as a member of the Committee on Analytical Reagents of the American Chemical Society and the Revision Committee of the U. S. Pharmacopoeia. The scope of this haok is indicated in the foreword by N. H. Furman. "This volume is based on the general plan of Murray's 'Standards and Tests for Reagent Chemicals,' hut a careful examination of its contents will convince the reader that practically every set of specifications, for the maximum limits of impurities and the methods of detecting and estimating them, has been critically studied and revised t o conform with more recent analytical procedures and the present established standards. These standards are. of necessity, based on theone hand upon the requirements of purity for the various applications of each substance. and on the other hand upon the present state of the difficult art of manufacture and purification of chemical substances. A comparison of the standards of the present volume with those of the book which it replaces gives clear evidence of the rapid nroeress that bas been attained in the nroduction of nurer and . more universally satisfactory materials, and in this progress the author of the hook has had a very significant share." The first eight pages of the haok specify the purity, concentration, and preparation of the test reagents. Pages M 7 3 list the reagent chemicals and standards in alphabetical order. On an average, about one page is devoted t o each substance. The formula and molecular weight of the compound is followed by a brief statement of its important chemical characteristics and physical properties, such as melting point, boiling point, and density. Then there follows a list of the maximum allowable impurities and a brief description of the methods used t o determine them. Most of the tests for chloride, sulfate, heavy metals, iron, etc., are quantitative. It is not sufficient, however, t o know how much impurity is present; the percentage purity of the reagent itself is often more significant. The author therefore, gives a method of assaying or determining quantitatively the active constituents of nearly seventy per cent. of the reagent chemicals. This he considers "one of the most effective ways of checking the quality of a chemical." Some of these assavs are based uoon a determination of ohvsical . properties, but most depend upon acid-base, oxidation-reduction, and precipitation titrations. The preparation and standardization of the volumetric solutions is described in ten pages, after which twenty-six pages are devoted t o a tabulation of the weights of different substances equivalent t o 1 cc. of the acids, bases, oxidizing, reducing, and other reagents used in the assays. These tables include values for many other substances, besides those analytical reagents listed in the book. The last seven pages of the text are devoted t o buffer solutions, indicators, and colorimetric determination of pH, which has many applications in the reagent tests. An adequate index of eight pages concludes the book. This volume is well printed an good paper and securely bound. It should prove a useful reference b w k in any laboratory where reaeent chemicals are emoloved and careful analvtical or testine . work is carried out. It isalso a storrhouse of analytical information nnd illu~tratrrthe more and morr precise and eonvrnirnr
Apa1En CHEMISTRY Ron ENGINEERS. A. F. H. Ward. M.A., Ph.D. (Cantab.), B.Sc. (Lond.), A. I. C.. Assistant Lecturer in Physical Chemistry in the College of Technology and the University, Manchester. Longmans. Green and Co.. New York City, 1936. xi 127 pp. 6 figs. 12 X 18 cm. $1.75.
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Here is a splendid little book which reminds us that the recent slogan "Buy British" may be wise, if not patriotic. The preface states that the book "is intended t o provide a practical course in applied chemistry for students of mechanical, municipal, or electrical engineering in technical colleges and universities. It will also he useful for students of pure chemistry needing an introduction t o applied chemistry." The book consists chiefly of concise directions for experiments hut also contains excellent summaries and discussions of methods. It is made up as follows: Part I, Water Examination, consisting of twenty-two experiments; Part 11, Boiler-Wster Treatment. nine experiments; Part 111, Corrosion, twenty-five experiments; Part IV. Coal and Oil, twenty-one experiments. Parts I1 and I11 seem t o be most complete in their treatment of Boiler-Water and Corrosion. Part IV is somewhat meager in its treatment of coal analysis. Such a text accompanied by suitable lectures would afford an excellent course for eneineers. More of our collezes will he training students in these industrial npplicarions. Dr. \Van1 has included sufficient thrureticol matter at most points to show rhr physirochrmicnl explanations for methods which t w often are presented inadequately. There are a few points which differ from American practice. Hardness is expressed in parts per 100,000. Potentials of metals in solutions of their ions are expressed with a negative sign for the more active metals. This, of course, has always been a matter of disagreement, even among different authors in this country. The book is well written and singularly free from errors. One might wish for more diagrams, or pictures, of apparatus used. Occasionally, also, mere references to source literature miaht be expanded profitably.
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DAG~ERRE-SCXRIFTEN. Erkh Stcngcr, Professor of Chemistry. Technische Hochschule, Charlottenburg. The author's private press, Berlin-Charlottenburg. 1936. 18 pp. 30 figs. 22 X 30 em. Edition limited to 150 numbered copies. Most of the Daguerre writings described in this brochure are in Professor Stenger's private collection. Francoiois Arago announced Daguerre's discovery t o the French Academy of Sciences on January 7. 1839, and described the process a t a joint meeting of the Academies of Arts and Sciences on August 19th of the same year. The essential details of the process were first published by Arago in the Comptcs Rendus, 9250-67 (1839). but the first widely circulated report of it was the brochure, "Historique et description des procCdCs du DaguerrCotype et duDiorama," which Daguerre himself published in Paris in the same year. This contained the reports of the Chamber of Deputies for June 15, July 3, and July 30, 1839, the decree of Louis-Philippe according to which Daguerre and NicCphore
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