NEW BOOKS says: I'. . . it is hardly possible to interpret on this basis

says: I'. . . it is hardly possible to interpret on this basis the abnormally high rates that are sometimes observed.” The reviewer is not aware tha...
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says: I ‘ . it is hardly possible to interpret on this basis the abnormally high rates t h a t are sometimes observed.” The reviewer is not aware that anyone has ever advanced any theory which will have a reaction occur at a rate that is faster than the molecules can come together. In fact, on page 62 the author says: reactions will still be regarded as taking place on collision between reacting molecules, but the nature of a collision will be defined more precisely.” I n other words, his dispute is not with the gencral idea of a collision theory but with the method of calculating the number and evaluating the effectiveness of the collisions. Such being the case, the relative success of the two points of view depends on the relative cleverness of the advocates of each in selecting a set of assumptions which will lead to a suitable interpretation of the experimental data. Hence table 40 on page 229, instead of showing the superiority of the “activated complex” theory over the “collision” theory, shows that the author was better able to make assumptions for the former theory in three cases and for the latter theory in two cases. Again, on page 72 the author claims that the “collision theory” for bimolecular reactions of complex molecules predicts rates 105 to 10” times faster than does the “absolute reaction rate theory” and is in disagreement with experiment by such a factor. No data are given to support this statement and the reviewer knows of data which are directly contrsdictory to it. Anothcr example is found on page 107, where he invokes the restriction on singlet-triplet trnnsitions to account for the slowness of some gaseous isomerizations, although on page 61 he has denounced the “collision theory” for failing to account for such slowness without the aid of such a crutch. In general, while the author is highly critical of what he calls “collision theory,” he is rather noncritical when applying his own point of view t o experimental data. For example, in table 30 on page 131 the data are supposed t o confirm a rough rule stated above the table, but the discrepancies between the experimental and theoretical columns run as high as a factor of 10’. The discrepancies between theory and experiment can also be brought out by comparing the ratio of the experimental factors with the ratio of the theoretical values for pairs of the reactions cited. Sometimes there is excellent agreement, but in others the ratios disagree by factors which range up to 10’. If one is t o be allowed that much leeway, it should be possible to find plenty of theories to fit the data. Actually, the collision theory must give the same result as the absolute reaction rate theory if equivalent assumptions are allowed. It has already been mentioned that the examples of reactions discussed have been chosen largely from gaseous systems. Since the book does not claim t o cover everything in the field of kinetics, the author should be allowed such a choice. It is unfortunate that he has not always covered the literature on those reactions which he does discuss. As examples might be cited the decomposition of dimethyl ether, where he presents the work of Hinshelwood (1927) but fails to consider that of Leifer and Urey (1942), and the thirdorder reactions of nitric oxide with oxygen and the halogens, where he fails t o consider the work of 0. K. Rice, which showed that the dimer of nitric oxide exists in amounts sufficient t o make it an important intermediate in the reactions. I n spite of the faults which have been mentioned, the book has its good points. It is written in a style which should not be too difficult for the average student to understand. There are 44 figures and 51 tables to illustrate the discussion. The reactions which are discussed are grouped in a logical manner. The book is well printed on good paper and is bound in the excellent form characteristic of the series. Taking all things into consideration, it is probably as good a book as is available for use as a text on this subject. G . K. ROLLEFSON.

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Colloidal Dispersions. By EARLK. FISCHER. 387 pp. New Yolk: John Wiley and Sons, Inc., 1950. Price: $7.50. Colloidal dispersions constitute an ever-present factor in our everyday lives. The scope of this field is tremendous. The content of the present book is restricted t o “technical aspects of the subject” and is directed primarily to dispersions of finely divided solids in

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liquid media. The author points out t h a t this type of system is of great industrial irnportance and states that “industries whose production values aggregate several billion dollars annually in the United States alone depend on this basioprocess.” As one reads this book one realizes that the author must have had wide experience within this field and that he has ably brought together an appropriate assortment of methods and devices for dealing with the various processes discussed. Included in the processes treated are those dealing with pigments, paints, and lacquers, printing inks, textiles, ceramics, and others. The first five chapters give a theoretical background relating t o various techniques that logically should be employed inindustrial laboratories. Pertinent discussions are given t o such topics as interfacial and surface energy, surface forces, electrical charges, flocculation, deflocculation or dispersion, and t o rheological properties. The remaining sever1 chapters :%redevoted t o manufacturing details and a description of the various types of apparatus used in different dispersion processes. I t is evident that the author quite justifiably considers t h a t the behavior of a colloidal system is dependent principally upon the surface or interfacial properties of t h a t system. He has contributed much from his own experience and has brought together relevant information and data from the literaturr. Altogether over eight hundred references are cited. While some of the material is of controversial nnturc, the author has given a n unbiased presentation of the work of others and furthermore frankly states, “Where available information ran low I have, on occasion, taken the liberty of speculating.” The exercising of this prerogative by the author has in fact enhanced the value of his contribution. The book is well organized, well written, and filled with ideas which will suggest new methods applicable t o various industrial problems. I t will be read with profit by a11 persons interested i n the field of colloid science, but will quite surely be read with most profit by the increasingly large number of those in industry who are confronted with problem related t o the preparation or t o the stabilization of colloidal dispersions and who have learned by experience t h a t significant information and data pertaining thereto have been, at best, widely scattered throughout the literature. T o those, this book will provide a real service.

F. E. BIBTELL

BOOKS RECEIVED (to February 9 , 1951) BUCKLEY, H . E. Crystal Growth. John Wiley and Sons, Inc., 440 Fourth Ave., New York 16. 1951.571 pp. Price: $9.00. CHU,Ju CHIR.Distillation Equilibrium Data. Reinhold Publishing Corporation, 330 West 42nd St., New York 18. 1950. 304 pp. Price: $6.00. DUTCHER,R. ADAM, JENSEN, CLIFFORDO., A N D ALTHOUSE,PAUL M. Introduction to Agricultural Biochemistry. John Wiley and Sons, Inc., 440 Fourth Ave., New York 16. 1951.502 pp. Price: $6.00. ELDERFIELD, ROBSRT3 . (Editor). Heterocyclic Conapounrls. 1‘01. 11. John Wiley and Sons, Inc., 440 Fourth Ave., New York 16. 1951.571pp. Price: $15.00. GRAY,DWIGHTE . , ASD MARTENS, JOHN H . Radiation Monitoring i n Atomic Defense. D. Van Nostrand Company, Inc., 250 Fourth Ave., New Tork 3. 1951. 122 pp. Price: $2.00. M A C ~ E V IWILLIAM N, M.The AnaIgtical Balance-Its Care and r’se. Handbook Publishers, Inc., Sandusky, Ohio. 1951.60 pp. POLLARD, ERNEST C., A N D D a v l ~ s oWILLIAM ~, L . Applied Nuclear Physics. Second edition. John Wiley and Sons, Inc., 440 Fourth Ave., S e w York 16. 1951. 352 pp. Price. $5.00.