tion of acetaldehyde and acetic acid from acetylene.

It is impossible for the reviewer to ex- press anything but admiration for this work because of its very complete and remarkably well-balanced treatment of almost all of the phases of our knowledge of organic chemistry.

FRANK C. WHSCMORB '

Catalysis in Theory and Practice. E. K. RIDEAL AND H. S. TAYLOR. Macmillan and Co., Ltd., New York City. Second edition, 1926. xv + 516 pp. 13.5 X 21.5 cm. $6.00 net.

Any user of the first edition of this important work knows intuitively that he must have a copy of the second edition. The rapid advances in our knowledge of catalysis since 1919 insure that the new edition cannot help but be greatly im- proved.

Drs. Rideal and Taylor have taken full advantage of their opportunity. The whole work has been completely revised, rearranged, and expanded. Three chap- t e n have been added and the text of the book enlarged altogether by about thirty- five per cent. Although only twenty pages have been added, this has become possible through the use of smaller type Chapters II-Theoretical Iutmduction- and III-The Measurement of Reaction Velocity in Catalytic Processes--of the older edition have been expanded so as to cover Chapters I1 to VI in this edition. The titles of these chapten are Criteria of Catalysis; Homogeneous Reactions; The Theory of Heterogeneous Catalytic Re- actions; Promoters; Mixed, Supported, and Protected Catalysts; Catalyst Poisons; and the Inhibition of Homogeneous Chemical Reactions.

This serves to show where the growth of our knowledge of catalysis has occurred. The theoretical part of the book has, in consequence, been enormously improved. The concept of active moledes and re- lated topics has been expanded from three to twenty pages, the properties and he-

haviar of solid catalytic agents from ten to thirty-two pages, and negative catalysis from one and one-half to fifteen pages. There is a section showing the correlation of the data of catalysis with the thermo- dynamic properties of solutions, a section discussing the structure and probable mode of formation of unstable complexes, and a section going very thoroughly into the subject of promoters and promoter action.

But it is not the theoretical part alone that shows improvement. Many new processes are recorded and described. Notable among these are the new processes for synthetic methanol and for synthetic motor fuels. The Claude, high- pressure process for nitrogen fixation is discussed. The chapter on Catalysis by Radiant Energy has been expanded fifty per cent.

The book is replete with references. Although the authors disclaim any attempt a t bibliography compilation, one cannot help but feel that they have included enough. The paper, binding and printing are a decided improvement over the first edition. Catalysis in Theory and Prac- tice is without doubt destined to stimulate very greatly our interest in and investiga- tion of that subject.

MALCOLM M. HARWO

Equilibria in Saturated Salt Solutions. W. C. BLASDALE. A. C. S. Monograph Series. The Chemical Catalog Co., Inc., New York City, 1927. 197 pp. 15 X 22.5 cm. $4.50 net.

This book is a summary of studies made over a long period of years by many people on saturated aqueous salt solutions. It does not attempt to cover all the data available, nor is i t a compendium of liter- ature references. Only the more impor- tant systems are considered. Nevertheless it should prove an invaluable aid to every worker in this field.

Although this monograph covers all twes of salt solutions from 2 to 6 comDo- . . nents, its greatest duel ies in thetr&tment