1456
JOURNAL OF CHEMICAL EDUCATION
interionic attraction throry of Dehye. Hiickel, Onsager, and others. The author points out that the conductivity of a solution will in general he determined by the relative number of ions and their mobilities, so that if the mobility changes can be accounted for, a change in the relative numben of the ions, that is, a degree of dissociation, may be calculated. The interionic attraction theory makes this p o s ~ sible because according t o i t conductivity changes are attributed entirely to the effrct of interionic forces on the mobilities of the ions. There are also chapt-rs in which relationships between conductivity and viscosity, methods of determining the equivalent conductivity a t infinite dilution, and temperature effects are considered. Among the problems considered which may be investigated by conductance studies there may be mentioned chemical analysis, dissociation of ternary electralytvs, nature of acids and bases, solvolysis, complex ions, and amphoteric electrolytes. The sections form well-written introductions t o these important subjects. The reviewer is disappointed that Dr. Davies feels "the chemist will judge the Debye-Hiickel-Onsager equations not by the manner of their derivation but by the degree of success with which they interpret and predict the results of experiment," and has written his book accordingly. Thus, less than ten pages of a third and introductory section are devoted t o a description of the theoretical aspects of the interionic attraction theories and, although the hook deals with the conductivity of solutions, only three of these pages may be said t o descrihe the new conductivity theory itself. I n this space it is possible to mention only the very simplest notions and to give the final equations, so that a reader does not have clearly before him the assumptions and approrimations which have to be made in order to calculate the "period of relaxation" effect (mare commonly called the electrical force of relaxation) and the "electrophoretic" effect. The degree t o
JULY.
1931
which a theory may be expected to fit experimental fact will depend upon these assumptions and approximations. Again, the author has all too briefly discussed the important theoretical significance of the effect of the application of high field strengths and high frequencies in the measurement of the conductivities. T t u s while the stated purpose of the book has been fulfilled to a remarkable extent, the interest of a research worker might have been stimulated to a greater degree by stricter attention to the theoretical details. This criticism should not be taken as an adverse judgment of the book, for it is primarily concerned with an account of experimental work. I t will certainly he welcomed by many persons as a clear, concise, and, a t the same time, romprehensive account of the conductivity of solotions.
1. w.
WII,LIAMS
Tne U N I V E R OF ~ ~WISCONSIN V MADISON,W~YISCONS~N
The Vitamins. H. C. SHEXMAN,Mitchill Professor of Chemistry, Columbia University, and S. L. Snnrm. Senior Chemist. Office of Experiment Stations, United States Department of Agriculture. Second edition. American Chemical Society Monograph Series. The Chemical Catalog Company, New 562 pp. 14 York City, 1931. xii figs. 16 X 20 em. 56.00.
+
In the preface the authors state that "an attempt has been made to summarize the very considerable amount of information which has been gained regarding the chemical natures of the individual vitamins, and the more voluminous knowledge regarding their rdles in life processes, their formation and distribution in nature, their relative abundance in different types of food materials and stability under the conditions t o which these are likely t o he subjected." "Recognizing that knowledge of vitamins touches closely the intellectual and professional interests of many other scientifically trained persons as well as professional chemists.
Vor.. 8. No. 7
RECENT BOOKS
we have sought to treat the subject with the interests of all probable readers in view, and have thus included more of physiological,pathological,nutritional, and health aspects than would otherwise be expected in a chemical monograph." The book contains seven chapters, a bibliography, and an author and subject index. Chapter 1 is devoted to the general considerations of the vitamin theory. The remaining chapters are devoted respectively to vitamin B (Bl); vitanin G (B3; vitamin C ; vitamin A ; vitamin D ; and vitamin E. Our knowledge of each vitacin is developed by an account of the individual researches in chronological order, which have brought to light its existence, effects of deprivation of, its distribution and properties. The subject is presented in the masterful manner to be expected from well-known investigators and teachers. The book is the best source of information on the subject of the vitamins. The bibliography occupies 184 pages and supplies approximately 3300 titles all of which appear to be selected for their importance rather than for completeness of reference. Complete titles as well as references t o the literature are given. The book will prove interesting and instructive to a wide circle of readers whose interests lie outside the fields of chemistry and the more restricted field of nutritional research. The objectives stated by the authors in their preface in the quotations given above have been achieved in a very creditable degree. E. V. MCCOLLUM SCHOOLOR HYOIBNE AND PUBLIC HBALTH BALrruonB, M*auL*ND
Structure Symbols of Organic Compounds. , of PhysiINGOW. D. H ~ C K HCollege cians and Surgeons, San Francisco. P. Blakistou's Son & Co., Inc.. Philadel139 pp. 29 plates. phia, 1931. viii 13.25 X 19.5 cm. $2.50.
+
This book has been designed as an aid to students and teachen of organic ehemistry. I t consists of three parts: (1) a
1457
statcmrnt of "the pertinent facts and fundamental concepts of atomic structure"; (2) a development of the "structure symbol." it5 advantages. its eketronic interpretation, and the use of the latter in the prediction of reactions; and (3) a list of the structure symbols of 991 organic compounds and the electronic structure symbols of 30 compounds. The structure symbol far compounds containing carbon, hydrogen, oxygen, and nitrogen differs from the ordinary structural formula in that no chemical symbols appear in the formula; in other words, it consists of lines only, hydrogen being represented by a point a t the end of a line; oxygen, nitrogen, and carbon being represented by points a t the junction cf two, three, or five. and four lines, respectively. [See J. CHEM.EDUC.,7, 8 3 6 1 1 (Apr., 1930).] The author claims for the structure symbol an advantage over the structural formula in (1) exactness. (2) compactness. (3) accuracy. (4) simplicity, (5) clearness. (6) uniformity, and (7) universality. The electronic structure symbol is obtained from the structure symbol by the addition of dots which represent ekctrons. Shared electrons appear on the lines of the structure symbol (or astride it) while the unshared electrons do not. In the case of polar compounds, shared electron pairs are shifted toward the atom having the greatest number of unshared electrons. The present structural formula seems so well established that it is not likely t o be replaced unless a much more desirable methcd of representation is devised. Any such method will have to overcome custom, and to do this its advantages must outweigh decidedly its disadvantages. The structure symbol d w s have the advantaze . of comvactness and simolicitv. . .. but is that sufficient to overcome the inmnvenience of having the chemical symbols omitted? Is i t not desirable to make our representation intelligible to, a t least. the scientifically interested public? Taking everything into consideration, the re:
