SEPTEMBER,1951
503
The electronic theories of valence introduced in Chapter I1 are used consistently throughout the book. Rather unusual in organic textbaoks is their extension to include the molecular orbital theory. The diagrams are excellent for its application both to benzene (p. 410) and to hutadiene (p. 67), the latter being used to illustrate Coulson's "delocalisation energy" ("but it is more usual to call it resonance energy") and for explaining 1,2- and 1,4addition. Two further unusual and interesting features of tho hook are (1) the Iiat of 50 English examination questions (pp. 660-2) chosen a t the level of the BSc. General Honors degree and Part I of the Special Honors degree of London University; and (2) the unusually good discussion (pp. 664-70) of organic chemistry publications and the methods of using them. The treatment of organic nomenclature is the least satisfactory feature of the book. I t would he somewhat confusing to an American, since the English method is naturally used whenever a difference exists. The author chooses, for example, consistently such names ss butan-2-01 rather than 2-hutanol or butanol-2. Particularly awkward is "hut-2-ene" (p. 63). However, even the differences and awkwardnesses might make the American student realize more fully the present state of flux of the subject, and it certainly does no harm to get the English paint of view! On the whole it is a solid, all-inclusive, well-written, wellprinted, well-illustrated textbook, including both classical and modern viewpoints. It seems to fulfill the author's hope when he says he has "included detailed discussions on developments of a straightforward nature and also of a. controversial nature, in the hope of encouraging the student to weigh up the evidence for himself." HELEN 8. FRENCH
0
ADSORPTION AND CHROMATOGRAPHY
Hamld Gomes Cassidy, Associate Professor af Chemistry, Yale University. Volume V of "Technique of Organic Chemistry," edited by Arnold Weissberger. Interscience Publishers, Inc., 360 pp. 53 figs. 54 tables. 16 X 24 New York, 1951. xin cm. 57.
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INTHE preface, the author has stated: "It is the objective of this hook to describe and explain, by discussion of principles, the various methods by whioh adsorption may be utilized in organic chemistry as a tool for the separation of mixtures." To fulfill this objective the author has "not only desorihe(d) thevarious waysin which adsorptionmay be used, but also (has)explain(ed) the nature of adsorption and of the phenomena associated with it." This book contains s. great deal of information on adsorption gathered from the literature, which will be of aid either directly or by analogy to the chemist who desires to use adsorption as a method of separation. These data do not represent a. compilation comparable to tables of solubility or boiling points which are so useful in designing separation methods based on precipitations and distillations. There is not a t present a full enough body of knowledge about adsorption to permit such a tabulation. I n the chapter on the Nature of the Sepamtion Processes, the author compares adsorption with other methods of separation which are based on the distribution of a substanoe between phases. No attempt is made to discuss s. large number of phasepair distributions but the examples illustrate the "similarities in principle and differences in application" of these processes. Various types of adsorption methods, including Batchwise Adsorption and Decolorization, Chromatography, Ion Exchange Methods and Partition Chromatography, are discussed. A great deal of valuable information is compiled in tabular and graphical form in these chapters. The nature of the processes and the theory are discussed briefly with adequate reference to more complete sources. Tho apparatus and materials required and the manipulations necessary to affect the separations are discus~ed adequately. More detailed descriptions of procedures for carrying out several typical separations m given in the final chapter.
As the author states further in the preface, "Emphasis on the needs of the organic chemist haa limited the discussion almost entirely t o the properties and uses of liquid-vapor, liquid-liquid and liquid-solid interfaces. . "In his 'Annotated Bibliography of Solid Adsorbents,' which covers the literature up to 1942, Deitz has listed some six thousand references. This represents only part of the literature in the much larger field of adsorption, and only someone who has attempted to read this literature can realize what an appalling task it would be to cover it completely. . . I have. .tried to cover a wide variety of phenomena and to show their connections with adsorption." To review this field is a huge task and in my opinion the author has done i t well.
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EDWARD R. TOMPKINS
U. S. NAVAG R ~ o r o ~ o a r cD~Er P. E I a E L*BOBATORI SANFRANCIBCO. CALIFORNIA
0
THE IDENTIFICATION OF MOLECULAR SPECTRA
R. W. B. Pearse, Assistant Professor and Reader, Imperial College, London, and A. G. Gaydon, Warren Research Fellow of the Royal Society, Imperial College, London. Second revised 276 pp. edition. John Wiley 8 Sons, Inc., New York, 1950. xi 12 plates. 20 X 28 cm. 58.50.
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THE ~econdedition of Pearse and Gaydon's oxoellent compilation of data on moleoular band spectra is larger than the 1941 edition by some fifty pages. New data up to 1947, with some dsta and references as late as 1949, have been added and in many cases the rearrangement of the tables in more compact form ha? made possible a considerable increase in ttie amount of material included. "Four new plates containing 26 enlargements have been added, the new spectra shown including systems of On, various hydrides and other molecules of general interest." As in the first edition, the compilation of available data has been limited to include "all recorded system of diatomic molecules, hut only those of triatomic and more complex molecules v.hich show well-defined banded structure and are of frequent occurrence in speetroseopio investigations." Data on complex organic molecules and on solutions have not been included nor i~ there any discussion of the theory of molecular spectra b u t these omissions do not detract from the usefulness of the book in its fundamental purpose of "facilitating the identification of moleculc~rs p ~ t r a . " The spectral region covered is, in general, from 10,OW A. to 2000 A. In the ease of the absorption spactrum of molecular oxygen however, dsta are given arr far as 1 1 ifi7
Although the book is essentially s, compilation of data from original papers, the authors have, in a number of cases, extended the recorded data by their own measurements., ,Their wide knowledge and experience in the field make their cr~tlcalselection of material from the literature particularly valuable. The data are presented in two sections: "The first section consists of a list of the strongest heads of the more persistent and better known hand systems of eaeh molecule in order of wave length, together with information as to origin, intensity in various sources, and appearance. The second section consists of individual lists of band heads for eaeh system of each molecule, accompanied by notes about the occurrence and appearance of the system, the nature of the electronic transition involved, the vibrational assignment of the bands in the system, and references to the sources of the data.'' The section called "Practical Hints" was an extremely useful feature of the first edition; this has been retained, with some additions, in the new edition. This material is not ordinarily available in textbooks and gives invaluable help to the person inexperienced in the identification of molecular spectra. The number of scientists who are concerned with the identification of band spectra is probably not great, but certainly this hook would be indispensable to those who are working in this field. In the words of the autham, "such a list can be of service not only to pure
