ANALYTICAL CHEMISTRY The last part of the second sentence in this paragraph and following sentences should read: “so a study waa made of the variation of carbon with depth and position of drilling. The carbon content of the top centers of the blocks were aa much as 0.3% higher than the bottom centers. As a result, the present procedure is to cast a block in a metal mold, and drill the sample from the top through the center of the casting as far aa the drill will go. This procedure gives the most uniform quick sample.”
JOHN R. BOYD James B. Clow L Sons Coshocton, Ohio
Bichromate Reflux Method for Determination of Oxygen Consumed SIR: It would appear that the authors of the above paper [Moore, Kroner, and Ruchhoft, ANAL. CHEM.,21, 953 (1949)) have overlooked the fact that silver is an efficient catalyst for the oxidation of acetic acid by dichromate-sulfuric acid mixtures [see, for example, Nicloux, Compt. rend., 184,890 (1927); Corde bard and Michle, Bull. SOC. chim. France, 43 (i), 97 (1928). In a paper by the writer [Muers, J . SOC.Chem. Ind., 55, 71T (1936)l a method was described for estimating the strength (oxidizability) of dairy effluents containing lactic and acetic acids and ethyl alcohol. In the presence of 0.25% silver sulfate all three substances were quantitatively oxidized under conditions otherwise similar to those used by Moore et al. The experimental work, which was only summarized in the published paper, did not cover all the pure substances examined by Moore et al., but it s e e m probable that the silver catalyst would have improved their results in most cases where there was a large deviation from the theoretical oxygen consumption. Central Laboratory United Dairies Ltd. London W. 12,England
M. M. MUERB
SIR:We wish to thank Muers for calling our attention to this rapid method for estimating the strength of a solution containing organic matter. Unfortunately, Muers’ procedure was published as a part of a study on the biological purification of whey solutions. The procedure for oxygen consumed used by Muers in this study was not stressed or given in detail; consequently, it was not cross-indexed in Chemical Abstracts. Therefore, in our bibliography search on procedures for oxygen consumed thw particular method was not found. This center has not followed directly studies on the purification of whey wastes and, therefore, we were not familiar with Muers’ work. An examination of Muers’ method indicates that it followed the same general procedure as that used by Ingols in this country. The procedure used by this laboratory is somewhat different in detail. This center is now engaged in a comprehensive comparative study of five procedures for evaluating the oxygen-consumed values of sewages and industrial wastes. In these studies between 50 and 100 replicates of various wastes are being examined by each procedure and statistical analyses are being made on the results, so that the most desirable method can be determined. As soon as Muers’ suggestion was received, Moore and Ludzack of this laboratory undertook an evaluation of the effectiveness of silver sulfate as a catalyst. To date completed studies, using 100 replicates of a large number of wastes, have shown that the procedure suggested by Moore et al. [ANAL.CHEY.,21, 953 (1949)l had advantages over all others. Consequently, the effectiveness of silver was studied by introducing the quantity of silver suggested by Muers in our dichromate reflux method. Ten repli-
cate portions of 18 organic chemicals have been examined to date with this procedure both with and without silver. This preliminary study has shown that the silver sulfate is very effective in catalyzing the more complete oxidation of most of these compounds. The oxidation of compounds, such as castile soap, caproic acid, glutamic acid, acetic acid, lactic acid, butyric acid, 0cresol, furoic acid, and ethyl alcohol, is raised to values between 80 and 98% by the addition of the silver. Chlorobenzene and spirits of turpentine are oxidized to 41.4 to 46.8% of theoretical by the addition of the silver salt. A few compounds, such as benzene, toluene, and pyridine, are apparently not affected by the addition of the silver and show very little, if any, increase in oxidation. Studies on the dichromate method for oxygen consumed with and without the addition of silver will be continued and a report on this work will be prepared in the future. Cooperative work with the American Society for Testing Materials subcommittee on water-borne industrial wastes and the Committee on Standard Methods for the Analysis of Water and Sewage on this method is being carried on. As a representative of both these committees, I again thank you for bringing Muep’ paper to our attention. Public Health Service Federal Security Agency Cincinnati, Ohio
C. C. RUCHHOFT
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Vitamin Methods. Paul Gyo~gy,editor. Vol. I. x 571 pages. Academic Press, Inc., 125 East 23rd St., New York, N. Y., 1950. Price, $10. This book is the first of two volumes which together will constitute a comprehensive treatise on vitamin methods. In the development of the subject matter, the presentation has been built around the variow techniques employed for assays (physical, chemical, microbiological, and animal assays) rather than the various vitamins. In the preparation of Volume I, Gyorgy haa had the assistance of the following collaborators: Eric T. Stiller, Physical Methods; S a d H. Rubin, Chemical Methods; Otto A. Bessey, Microchemical Methods; E4mond E. Snell, Microbiological Methods; Erich Hirschberg, Use of Optical Instruments. Where several alternative methods are available for a given physical, chemical, or biological assay of a vitamin, these are described in sufficient detail to obviate the necessity for consulting the original sources. Where poasible, the most reliable and widely used procedure is indicated. One of the significant features of this volume is the concise and direct approach employed in presenting the various steps involved in the assays. Preceding the actual details of the assay for each vitamin, a section is devoted to the historical development of the analytical procedure. Pertinent explanatory material relating to the application and interpretation of the technique is usually incorporated in this section, rendering such valuable information available without encumbering the actual laboratory directions. Definite statements on accuracy, precision, and limitations are usually presented if available. Certain sections have not included aa much of the more recent literature as might have been possible. Thus, the section on physical methods, with 340 references, discusses only three papers published subsequent to 1946. The book will be of value to workers in various fields concerned with nutritional problems.
E.M. BICKOF
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V O L U M E 22, NO. 6, J U N E 1 9 5 0
Metal shadowing as a technique is given a full chapter and is used almost universally on all micrographs. Surface replicas are treated with emphasis on crystals and body tissue such as teeth rather than the metallurgical field. Chapters on particle suspensions, viruses, and macromolecules reflect the extensive experiences of the author in microbiology. A discussion of the structure of macromolecular solids introduces a visual or mechanistic approach to colloid chemistry and provides a common meeting ground between the chemist and the biologist. The author concedes that electron microscopy is in a high state of flux and that the book describes the present status, to point out and arouse interest in the possibilities of this new instrument. Newcomers to the field of electromicroscopy will find the book a pleasant but thorough introduction to the subject. Those engaged in the field will value it for placing much experience and many quick references under one cover. DONALD L. KATZ
The Chemistry of Industrial Toxicology. Hewey B. Elkine. ix 406 pages. John Wiley & Sons, Inc., 440 Fourth Ave., New York 16, N. Y.,1950. Price, $5.50.
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This useful book, by a well recognized industrial hygienist, will be of greater value t o the individual with limited knowledge of the problems of industrial evironmental control than to the experienced hygienist. I n the largest subject division, more than 300 elements, inorganic compounds, and organic compounds are briefly discussed with respect to their industrial hygiene significance, and many of them are qualitatively related, as to hazard, to the more common industrial operations and processes. I n this, the author has incorporated much useful experience of the Division of Occupational Hygiene of the Massachusetts Department of Labor and Industries. In developing the subject of “maximum allowable concentrations,” and including a further modified list of values, the author’s statement “values based on inadequate data are enclosed in parentheses” may imply to the less experienced in this field a reliability for the values not so qualified which many do not have. The sections on air-sampling devices and analytical methods and procedures are well organized. The abridged experience with respect to such items as the use of activated silica gel and carbon and of absorption in nonreacting liquids will be useful to the newcomer t o this field. For the majority of the approximately 100 substances listed, only one analytical method is given. These are usually the generally accepted procedures and are well selected as to adaptability by a good analytical laboratory. I n general, the descriptions are sufficiently complete so that a reasonably good analyst could carry out the procedure without having to refer to the original literature. JAMES H. STERNER Precis d’halyse Qualitative. Robert Flatt. 237 pages. Libraire de l’Universit6 F. Rouge e t Cie., SA, Lausanne, Switxerland, 1949. Price, $6.50 (28 Swiss francs). The first part of this excellently organized and well written book summarizes in concise, easily understandable form those basic principles of physical chemistry which a student must grasp and apply if qualitative analysis is to be more to him than cookbook procedure. The basic techniques of laboratory experimentation and observation are separately summarized and taught by a special group of experiments. A systematic concise description of the reactions of the commonly encountered ions provides the basis for presenting the scheme of analysis in the form of a series of tables. Methoda for fluxing insoluble substances, short cuts for rapid orientation, and possible sources of interference and difficulty are given full, yet concise consideration. ?‘he book is so well balanced and well written throughout that it is impossible to select any one section as better than the others. J. W. PERRY Electron Microscope-Technique and Applications. Ralph W . G. Wyckoff. vii 248 pages. Interscience Publishers, Inc., 215 Fourth Ave., New York 3, N.Y., 1949. Price, $5.
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The subtitle is very appropriate, for less than 20% of the book is devoted to microscopes, their construction and adjustment; the remaining 80% covers the preparation of specimens for examination, typical electron micrographs, and an interpretation of their significance. The book is primarily an account of the author’s experiences; about 175 micrographs out of the 202 illustrations were made in his laboratories. The reproductions are of high quality, their purpose is explained, and the author’s interpretation is clearly stated. A complete bibliography by topics is given a t the end of the chapters.
Modern Industrial Spectrography A two-week intensive course in modern industrial spectrography is to be given by Boston College, Chestnut Hill, Boston, Mass., from July 24 to August 4, 1950, particularly designed for chemists and physicists from industries in the process of installing spectrographic equipment. Applications should be sent to James J. Devlin, Physics Department, Boston College, Chestnut Hill 67, Mass.
International Congress on Analytical Chemistry Plans for holding an International Congress on Analytical Chemistry in Britain in 1952 are progressing. The Council of the International Union of Pure and Applied Chemistry has granted its patronage. The proposal waa thought t o be in accord with one of the major decisions taken at the September meeting of the International Union, when six autonomous sections were formed, one of them concerned with analytical chemistry. A meeting of the Section on Analytical Chemistry is expected to be arranged to coincide with the 1952 International Congress on Analytical Chemistry. The Executive Committee, under the chairmanship of the president of the Society of Public Analysts and Other Analytical Chemists, G. Taylor, has under consideration the location of the congress, publication of papers, and the scope of subjects to be discussed. Sir Wallace Akers has been made chairman of the Finance Committee and Sir Robert Robinson, president of the Royal Society, is acting as chairman of the General Committee. The honorary secretary of the congress is R. C. Chirnside, Research Laboratories, General Electric Co., Ltd., Wembley, England. International Microchemical Congress. Graz, Austria, July 2 to6 Electron Microscope Society of America. Hotel Statler, Detroit, Mich., September 14 to 16. Eighth annual meeting Instrument Conference and Exhibit. Instrument Society of America, Buffalo, N. Y., September 18 to 22 Fourth Symposium on Analytical Chemistry. Louisiana Stata University, Baton Rouge, La., January 29 to February 1, 1951 I
