rest of the hook. In the chapter On thermachemistry the authors consider heat evolved as positive, and in the thermodynamic derivations they use heat absorbed as positive, hut nowhere is this change in convention explicitly stated. The who wishes to correlate the ...- -student day's assignment with his previous work will therefore find on page 78 that heat a t constant pressure equals heat a t constant volume minus the work done, and on page 304 that heat a t constant pressure equals heat a t constant volume @Gusthe work done. If he substitutes the data for the dissociation of nitrogen tetroxide, given on page 306,in the integrated van't Hoff equation on page 305, he will not check the authors' calculation, for they, without explanation, use Q in this example as heat aolued, though in the next example Q is used as heat absorbed. He will find the same uncertainty on pages 372 and 373. The good student will desire to have conventions suggested which enable him to calculate, from a given set of data, the directionas well as the magnitude flow. The book is free from typographi~al errors. Among the oversights, however, is the discussion (page 352 et seq.) introducing "Henry's law," although the law is left undefined. The use of the logarithm tables in the appendix would he facilitated if the parts of a table were printed facing each other, and not on both sides of a leaf. Some teachers would prefer to have included in the paragraph on the methods of expressing solution concentration, the expression in terms of mols per 1000 grams of solvent; others would qualify the statements on the conservation of mass in the light of modem physics. The student might well be told that the "triple point" for water is not exactly a t O'C. and the reasons why it is not. These latter criticisms are of secondary importance. The teacher who has a limited time in which t o introduce a class to some of the principles of physical chemistry should examine the hook. L. E. STEINER OBSRLINCOLLBUB OBHRLI-IN, orno
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Practical Chemistrg by Micro-Methods. EGERTON CHARLES GREY,D.Sc., F.I.C. (Lond.), M.R.C.S., Professor of Chemistry. Government Medical School, Cairo. W. Heffer and Sons, Ltd., Cam124 pp. 16 illusbridge, 1925. ix trations. 13.5 X 21.5 cm. 4s. 6d. net.
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The purpose of the book may best be judged by quotations from the preface: "It must be evident to many that the time has come for a change in some of the methods of teaching practical chemistry. Classes seem to get larger every year . many experiments which could once be performed hy.each individual must perforce he omitted, and there is a tendency t o meet the situation by adapting the practical course t o the convenience of the laboratory rather than t o the individual The method of needs of the students. practical microchemistry is that of working with minute quantities of material. specks of solids, drops of liquids. With this method the difficulties which would hamper many a laboratory will be found There is nothing which a t to vanish. present is done by students with large a paratus that cannot he done with the r9 m~cro-method,hut there is much that can be done with small apparatus that is a sheer waste when done an the larger scale. . A student's whole outlit may he put upon a tea-tray, and with all his laboratory thus a t hand the student may sit down t o his wark with consequent sparing of fatigue to himself and t o his teacher.. . The methods of microchemistry are exceedingly rapid. .With this sparing of time i t follows that much more work can The he gat into the working hours. economy also in energy and in expense is enormous, with the result that i t is possible t o cover a much broader field of study. . This hook is intended for schools or for the earlier part of a university course and it covers the practical wark required by the conjoint hoards of the Royal College of Physicians and Surgeons. While describing the methods of microchemistry, i t indicates also how a practical course may be broadened to include exercise in
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VOL.6, No. 9
RECENT
elementary physical chemistry, qualitative analysis, volumetric analysis, and a brief introduction to organic chemistry is given. The hook is well written and the author has accomplished his purpose, but i t is doubtful if i t will meet the requirements of students in this country. H m o e r , it should be read by every teacher of chemistry, because i t contains an idea which may revolutionize labora- , tory instruction in our high schools, colleges, and universities. The use of the microchemical methods, particularly for analysis, is rapidly increasing. Is the time coming when we can walk through a laboratory of organic chemistry in one of our large universities and see the students sitting a t desks making small amounts of their preparations quickly and studying the properties of substances with completeness and accuracy? There would be almost no noise, no odor, and any danger would be reduced t o a minimum. More laboratory work could be done better in half the time now consumed without tiring the student. The advantages gained by this factor alone would be numerous. The author bas not emphasized sufficiently the improved technic which follows training in the microchemical methods. Students trained from the beginning in microchemistrywould bemuch better fitted for the study of medicine. biology, and related sciences. "Chemists" trained in this way would acquire a splendid laboratory technic. As the laboratory work would be more complete a better knowledge of the practical side of chemistry would be obtained. As organic chemists throughout the world are adopting the methods of quantitative organic microanalysis developed Largely in the Medical-Chemical Institute of the University in Graz the teachers of chemistry may adopt, in part a t least, this idea from Cairo. m ~ P T. n K. CORNWELL
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Inorganic Chemistry for Colleges. WILLIAM FOSTER, Ph.D., Professor of Chemistry, Princeton University. First edition. D. Van Nostrand Co., New York City, 1929. viii f 837 pp. 212 figures. 13.5 X 21.5 nn. $3.90.
This book is designed for college students who have had a high-schwl course in general chemistry. I t is divided into four parts as follows: Part I(112 pages). Terminology,thelaws of chemical changes, symbols, formulas, equations, the gas laws. crystal structure, radioactivity, atomic numbers, classificationof the elements, and the modern theory on ihe structure of matter. Part I1 (386 pages). The non-metals in general, including also a chapter on solutions, the ionic theory, oxidation and reduction from an electronic standpoint. and colloidal chemistry. While carbon is discussed in this section organic compounds proper are left for Part I V . Part III (221 pages). The Metals. Besides a discussion of the metals and their properties this section includes a chapter on electrochemistry. Pert IV (71 pages). This is called the Supplementary Part and is devoted entirely t o organic compounds. At the end of this section there is an excellent list of 144 problems with answers. These illustrate principles taken up in the entire hook. The appendix contains the usual tables and also a table of logarithms. Many photographs of men, including Arrbenius, MendelCeff, and Richards, are placed throughout the book. At the end of each chapter a set of questions is given, varying in number from 15 to 25 and thoroughly covering the material taken up in the discussion. This book does not leave out any of the essential facts usually taken up in elementary chemistry texts. I t passes over some of the details given in these, hut the essential difference is that the subject matter is developed more thoroughly. For example: such subjects as catalysis, crystal structure, and the more Gmmon
