Recent Books Electrical Precipitation. SIR OLlvHR LODGE. D. Sc., F.R S. Oxford Univernty Press. London: Humphrey Milford, 1925. I1 40. 7 illustrations. IS X 24 cm. $l.OO.
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A lecture delivered before the Institute of Physin in London during October. 1924, the book constituting Volume I11 of Physics in Industry. Th. author presents io n very interestmg genera1 dlsc"s.ion the fundamental con-
Chemistry, Columhis University. Second Edition. D. Van Nostrand Company, New York. 1926. X 680 pp. 138 figurer. 13 x 21 cm. 64.50 net.
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This hook is described by the author as an abridgment of his "Manual of Industrial Chem istry," for classes lacking sufficient time t o cover the more extended treatise. One familiar with the larger work. which is a collection of descrip-
.. of electrical precipitation, the book ta of particuInr interest t o all those who are interested in the art. The author divides his subject into three parts: first, naturd precipitation, second, artificial precipitation, and t h r d , the combination of the two, with suggested mctcrologienl poroibilities. Under the firrt heading the author diseurses the foxes active in bringing about atmospheric electrical charge. and natural preripitation. He lays particular emphasis on the investigations conducted by Dr. George C. simpsoo in his study of thunder storms. After diacun3ing the varioun methods by whieh suspended water particle might be charged electrically, the author oetr forth the eooditions under whieh natural prceipitation can take place. I" the second chapter the author gives a brief review of the history of the development of the art of artificial electrical precipitation and a brief synopsis of the practical application of the process of electrical precipitation with particular reference t o the collection of acid mists and smelter fumes. The author add. a brief discussion of the carbon smoke problem existing in modem cities. I n the third chapter the author makes a foreeast a . t o the possibilities whieh may result from an extension of prcreot-day knowledge and the application thereof to the dissipation of fogs, the production of rain, nod the eonlequcnt control of climate. An Appendix of 4 pages m d 7 illvrtrationa U added. giving a brief descriptmo of the apparatus and equipmmt used in the nppiieation of the Process of E l e c t r i d precipitation in a rvlfurlc acid plant, a tin smelting plant, and an iron hi& WALTBR A. S C H ~ D T furnace plant. Elements of Industrial Chemistry. ALLBN Roozas, Supervisor of the Industrial Chemical Engineering Course and Head of the Departm m t of Industrial Chemistry. Pratt Institute. Brwklyn, New Yo& Lecturer on Industrial
reading this work. Consequently, this book represents the statements of authorities in each special 6eld rather than of one man, a manifest advantage. The discu$rion of the various topics is very elear. and includes as much detail as a student could be rearonably expected t o learn io n year's time. Few of the chapters are long enough t o tempt the student to .Em over the surface. mianng all but the high spots. The materid presented appears to be quite up-to-date. The reviewer feelo that some subjects have been overemphasized and others of equal or g r e a t s importance almost neglected. The chap. ters on perfumes and essential oils and on leather are disproportionately long, while sueh topics as organic .wlolvents, synthetic dyes and drugs, and nitrogen fixation are dealt with very briefly. The book is essentially descriptive and, as such, is suite satisfactory. I t seems that a real opportunity is being lmt in failing t o p-ent more definitely the application of chemical principles t o industrid processes. as in the Haber process, synthetic methanol, and many other examples. Students usually miss such points unless they are forcibly presented to them and, a3 a conocquence, fail t o see the rpa1 importance of much of their college work. The criticism offered must not he taken t o mean that the book is without merit. The reviewer feels that this text is one of the moat satisfactory for use in a short course in industrial chemistry, especially if thecourse is to be entirely descriptive. JOHN H. GARDNER The Carbon C o m ~ o ~ n d 8 C. . W. POIIIBR. Ginn and Co., Boston. Revised edition, 1926. ix 501 pp. 15 X 23 cm. $400.
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"This volume constitutes an outline of an e l c mentary mume in organic chemistry as presented t o sophomore students in the Univeraxty of California. The scope of the book is limited t o a presentation of fundamental principl- and gmem1 reactions. Some of the doctrines of t h t
