410
NEW BOOKS
adsorption; surface potentials; the mobility of surface molecules. In the case of a number of these subjects many will, perhaps, feel that the treatment is rather slight and inadequate, but even if this may be so, the discussion of the various topics, all of considerable interest a t the present time, will direct the attention of the serious student to the paths along which the subject is advancing and will help him to take up the fuller study of one or more of the subjects discussed. More than this can scarcely be demanded of such a book as the one under review. A. FINDLAY. Die Losungsgleichgewichte der Systeme der Salz ozeanischer Salzablagerung. By J. D’ANs. Quarto, 254 pp.; accompanied by 31 tables of graphs and diagrams, which are bound separately. Kali-Forschungs-Anstalt, Berlin. Verlagsgesellschaft fur Ackerbau, M.B.H., Berlin S.W. 11, Dessauer Strasse. The writer of this monograph, who worked in the laboratory of van’t Hoff on this subject, has here revised and recompiled all of the information relating to it now available. I t forms a complete summary of the facts known regarding the equilibria which exist between water and salts yielding chloride, sulfate, sodium, potassium, magnesium, and calcium ions, in either their simplest or most complex mixtures. In part I, one finds forty-seven pages devoted to a clear and systematic discussion of solubility determinations, methods of ascertaining the composition of the solid phases left after such determinations, and methods of fixing the constants which define invariant points; also the results of the application of the phase rule to the study of such data and discussion of the graphical methods of representing such systems. There are one hundred and eighty-eight pages devoted to the discussion of the forty-six salt systems, in which all of the data relating to combinations of water and from two to all six of the ions named, have been compiled and submitted to critical analysis. One is surprised a t the large amount of such data which has accumulated since the last summary by van’t Hoff. The composition of solutions has been recalculated, where necessary, and tabulated in terms of moles or double moles per 1000 moles of water, and in many cases in grams per 100 grams of water also. These data have been plotted on coordinate paper on a scale of 2.5 moles or 2.5 degrees per centimeter, the most probable course of the corresponding graphs drawn, and the whole reduced by photographic reproduction to a series of graphs and diagrams on which one centimeter represents 5 moles or 5 degrees. It is possible therefore, with the use of a lens, to read off compositions t o 0.1 mole and temperatures to 0.1 degree. These graphs and diagrams make up most of the material reproduced on the thirty-one plates of part 11. The volume clearly represents the results of an enormous amount of work and gives evidence of having been thoughtfully and carefully compiled and edited.
w.c. BLL4SDALE.
