VOL.8, NO. 4
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on Tiipfelanalyse, by DR.FRITZ FBIGL, a t the Eighth Colloid Symposium. The Privatdozent, University of Vienna. exceedingly wide smpe of the studies J. F. Bergmanu, Miinchen, Germany. made in the field of wlloid chemistry is 1931. xii 157 pp. 83 figs. 15 X rdected in the diversity of topics touched 23.5 cm. Rm. 12.80. upon by the papers in this Monograph. One finds studies of such fundamental I n the first few lines of the preface of problems as coagulation, stabilization. the first edition of "Mikrochemisches adsorption, optical properties, determina- Praktikum," Emich forecasts the more tion of particle size, ultra filtration, swell- general use of microchemical methods: ing, electrical phenomena, and other "I believe the time is not far off when papers dealing with applications of col- we must demand from the majority of loid chemistry to numerous fields, among our younger professional colleagues a cerwhich are photography, anesthesia, be- tain familiarity with these (micro) methhavior of clays and of paints, and the ods." Micro methods will never entirely removal of carbon monoxide from auto- replace macro methods, but their use is mobile exhaust gases. increasing rapidly, and there are times That scientific knowledge is accumulat- when they are absolutely indispensable. ing a t a tremendous rate is apparent to The appearance of the second edition every student of any branch of science. of Emich's "Microchemical Practice" is, The publication of the increasingly large therefore, very timely, as it includes a amount of work being done in colloid description of the absolutely necessary, chemistry performs a valuable function as distinguished from the desirable, equipin the training of chemists. On the one ment of the microchemical laboratory, band, the multiplicity of subjects c o w e d and also a discussion of the methods will arouse in the student a keen apprecia- available for carrying out any operations tion of the magnitude of the field of likely to be encountered. chemical knowledge, yet, an the other Part I of the book is devoted to aphand, the emphasis which is made in paratus and methods, and is subdivided studies of colloids on phenomena ac- into sections A and B, the former dealing curring a t interfaes will offer him a with qualitative and the latter with quanbasis for wrrelating and rationalizing the titative methods. multitude of facts with which he must deal. Part I1 includes many laboratory exerThe series of Colloid Symposium Mono- cises, and provides the student with graphs constitutes a valuable part of the laboratory directions wbich should give literature of colloids and this latest volume him a good knowledge of the micro reacwill find its place on library shelves to aid tions of the wmmon inorganic cations the student in his task. Its value as a and anions, and a training in the more reference is marred to some a t e u t by the common procedures of analytical and synoccurrence of five emoneous page refer. thetic organic microchemistry. As the ences in the table of contents and a t least title states, the hook does not cover the some of these errors are repeated in both same field as does Pregl's "Quantitative the author and subject indexes. Never. Organic Micmanalysis." The short section by Dr. Fritz Feigl theless, taken as a whole, this volume is a serves well t o introduce a very useful contribution of great value. S. AUAN LOUGH method of analysis, which, for lack of a bettu name, might be called "drop analyUNIVBRSITV DP NBVAD* Rsso, NBVAD* sis." Included are a general description of the aims and technic of the method. Mikrochemisches PraMikum. F. EmCH, and a number of laboratory experiments . which the student may acquaint himProfessor a t the Techniscbe Hochscbule, bv Graz. Second edition. With a section self with some of the common operations.
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JOURNAL OF CHEMICAL EDUCATION
The experiments are selected from the field of inorganic chemistry. A student who has worked through this book in an intelligent way should he in a position to c a m on microchemical work unassisted, devising for himself new methods when the need for them arises. Print and paper are good, and references to the original literature are frequent. The book should be a worthwhile addition to the library of any one interested in microchemical methods. NATHANL. DRAKE UN~YBLSITY OR MARYLAND COLLBCH
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Non-interpolating Logarithms, Cologarithms, and Antilogarithms. FREDERICK W. JOHNSON, M.A.. Instructor of Chemistry, California College of Pharmacy, University of California. Fahrikoid edition, No. 2 of the Simplified Series. The Simplified Series Publishing Company, 1381 Third Avenue, San Fran23 PP. cisco, California. 1930. x (tables, occupying 96 pp., not numbered). 15.75 X 21 cm. $2.25.
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The hook contains an introduction t o the theory of logarithms with illustrations of their use in calculations; illustrations of the use of the non-interpolating tables; tables, and explanation of formulas, for the calculation of the logarithmic trigonometric functions of small (or large) angles; tables of constants with their logarithms and cologarithms; and the following non-interpolating tables: A five-place table of logarithms and one of antilogarithms for all numbers of five significant figures. A five-place table of cologarithms for numbers of three signifcant figures. Four-dace tables of loparithms, of cologarithms, and of antilogarithms for numbers of four s i d i c a n t figures. The unique feature of the new tables is the printing arrangement which enables the author to give, directly in the tables, logarithms which in ordinary tables are obtained with the aid of interpolation. The number of pages required is not ex-
APRIL,1931
eessiv-just double that required for the common interpolating tables. Each logarithm, being read directly from the tables, has a value which is the properly roundedoff value of the corresponding logarithms in six- or seven-place tables. Thus there is, in these tables, no discrepancy between the logarithm of a number obtained from the four-place table or the five-place table. The tables have been adequately proof-read, or will be soon, since the publishers announce: "For each individual figure in the following tables that is found to be numerically incorrect, a complimentary leather-hound copy of this book will be sent to the person who first reports such an error." Two considerations will weigh with the teacher who recommends tables of logarithms for his classes-speed in the use of the tables and accuracy in the final result. The student will make greater speed getting the logarithm by inspection of a table than by interpolation. It happens, however, that in most calculations where five-place accuracy is desired in the product, some of the factors have four figures or less. The logarithms of such factors are read directly from the common logarithm tables, and are read more quickly than from the non-interpolating tables. One may therefore predict that, due to the two opposing effects on the speed of calculation, there will be no great difference favoring either the interpolating or noninterpolating tables. The accuracy of the final result depends both on the accuracy of the table used and on that of the user. It is a wellknown fact that an interpolation correctly done sometimes yields a result which differs from the corresponding rounded-off value from a more comprehensive table. Thus, a five-place table, for the logarithm of 273.1, gives 2.43632, an interpolating table gives 2.4364 and the non-interpolating gives 2.4363, as it should. It should be remembered, however, that the value from the nan-interpolating four-place table is a rounded-off value, and that the sum of such rounded-
