thread he finds in these charts with their flow lines, which serve to connect related subjects and persons. Marginal references t o British sovereigns and American presidents help to fix periods of time. The veni comoleteness of these charts is their sole drawback for there is so much material incorporated in them that i t is difficult a t times to follow the connection. COLINM. MACKALL
The Phase Rule and Its Applications. ALEXANDERFINDLAY,M.A., D.Sc., F.I.C., Professor of Chemistry, University of Aberdeen. Longmans, Green & Co., New York and London, 1927. 326 pp. 165 Sixth edition. xv illustrations. 21 X 14 em. $3.50 net.
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Twenty-four years ago Professor FindLay wrote, "the desire having been to explain as clearly as possible the principles underlying the Phase Rule, and to illustrate their application t o the classification and investigation of equilibria, by means of a number of cases actually studied." He expressed also his desire t o make the h w k elementary enough for the beginner while retaining such a thoroughness of treatment as to give him a really satisfactory foundation in the subject. How well he has attained his object, the use of the hook by thousands of teachers abundantly attests. One planning to give a course in "Phase Rule" instinctively thinks of "Findlay" as his text. This sixth edition will still further confirm aU users in this thought. Twenty-eight pages have been added since the fifth edition. This does not seem so much, but the real excellence of the new edition lies in the choice and arrangement of material. Many sections have been entirely rearranged and rewritten, notably the sections on oneand two-component systems, with considerable increase in utility and clarity thereby. The practical applications of the subject have been stressed more than ever. The sections on reciprocal salt pairs and salts with a common ion have been con-
siderablyexpandedandimproved. Smits' theory of allotropy and the nature of the equilibria in intensively dried systems are discussed briefly. One feels that the applications in metallor;raphy profit~. -~ and peolom might ably be expanded somewhat. Also the wisdom of dropping the chapter appearing in former editions on blast furnace equilibria is to be doubted, although real criticism along this line is unfair. One must draw the line on material t o be included somewhere. The reviewer notes with satisfaction the much more extensive discussion of the Clapeyron-Clansius equation and its application to phase transformations. I t is possible to repress mathematics too far in such a work. I n fact i t seems a pity that a really satisfactory derivation of the phase rule itself has not as yet been included. MALCOLM M. HARINO
in General Chemistry. Exercises CH-ES M. ALLEN,M.A., Head of the Department of Chemistry, Pratt Institute. John Wiley & Sons, Inc., New York City. Second edition. 1927. 63 pp. 20 X 26 cm. 81.75. This book consists of sixty-two experiments covering first-year chemistry. The directions are given clearly with explanations when necessary, together with the necessary precautions. The text contains an entire page of laboratory directions, which are omitted from most texts hecause they appear too obvious, with the result that the student becomes familiar with them only by the end of the term. The attention of the student is called to the things t o be observed by questions throughout the procedure, while questions of a general type appear a t the end of each experiment. The manual carefully avoids imparting information which a student can obtain for himself. The experiments in most cases are well selected, but distillation might be carried out more conveniently with a flask than a retort. The type is of good size, clear and printed an loose leaves, well secured in a
