tho methods of statistical thermodynamics (cven though its fundnmental assumptions are beautifully described), and n~hich,throt1ghont,cmpIoy8 arathersophisticated mathemeticnl physienl language. Thus, in some chapters, we find a vector and tensor notation, encounter such mathematics1 nations as Jacohians and Legendre Transform&ms, and in Chapter I1 we read about quxntum mechanical eigeniunctions and dcgeneratc states. This is too much for o w nndorgraduates. As for t,he merits and weaknesses in specific arms we may refer to the many reviews of the first edition, hearing in mind the changes and improvements referred to above. I n tho May, 1950, issw of THIS J ~ T R N A Gcorge L, Scatchard has correctly labeled this hook "very personal." Although this characterization is &ill very much to the point, this reviewer n-odd like to emphasize that the Guggenheim approach also has many excellent aspects. Even if one does not a l w a y ~prefer the "Guggenheim rules" over possiblt: alternatives, x careful reading of many parts of t h i ~book will greatly increase one's insight, into t,he field of thermodynamirs and its application to chemistry. The style is very clear throughout and the printer has done a beautiful job. J. Dl? AEER U m u e n s ~ ~01,r C a ~ o n o o B O U L ~ ECRo.~ o n * o o
CHEMICAL ENGINEERING PRACTICE. VOLUME 3 Edited by H. W. Cremer and T. Dovies. Academic Press, Inc., New York, 1957. xviii 523 pp. Figures and tables. 16.5 X 25.5 Em. $17.50.
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THEpresent volume is the aecand on the "Solid State," hut ns we saw previously [J. CHEM. EDUC.,34, 207 (1957)l the firat of these dealt largcly with alloys and metallurgical systems. This volume is devoted largely to the unit operations of siscreduction and separation. The first quarter of thc hook discusses principles of size reduotion, methods of pizing analysis, crushing, grinding and equipment. Separation is discussed more broadly, as screening and classifying, t,ahling and jigging, flotation, sedimentation, wet classification, dense medium coal washing, 2nd air flow selection. Three chapters cover mixing of solids, storage and handling of solids, and sxmpling, measuring and gauging of ~olicls. The final two ehsptors are on cleaning gaseous media hy rydones, or hy elcrtrv-prtreipitatiorr. blueh of the material in t,his volumc falls in fields of w o ~ kof mechanical or metallurgical engineers, and their viewpoints are apparent. There is no other modern book on the general subject of size reduct,ion and fieparatian. This hook is an excellent volume covering this field. K E N N E T H K. KOBE
U m v ~ n s O~ F~TEXAS r o a n r . TEX*~
JOURNAL OF CHEMICAL EDUCATION
