RECENT BOOKS BIBLIOOEAPHY OP SOLID ADSORBENTS.Vidor R. Deite. Research Associate for the U. S. Cane Sugar Refiners a t the National Bureau of Standards. A Contribution from the U. S. Cane Sugar Refiners and Bone Char Manufacturers and the National Bureau of Standards, Washington, D. C., 1944. lxxxi f 877 pp. 17.5 X 25.5 cm. $12. This volume is the outcome of a literature survey undertaken in connection with a broad research program on the nature and uses of boneblack and other adsorbents. This investigation is sponsored by the United States sugar refiners and bone char manufacturers and is being carried out a t the National Bureau of Standards in accordance with its Research Associate Plan, under the supervision of Frederick Bates and the immediate leadership of the author. I n an introductory text of 73 pages the theories concerning the nature of adsorption are b r i d y reviewed and the history of adsorbents and their applications is traced. from the earliest recorded use of boneblack as a pigment in Egypt in the year 2650 B.C. to the present day. Special attention is paid t o bone char and vegetable carbons and to the part they have played in the development of sugar refining. The use of carbons for other purposes, such as gas or vapor adsorption, water purification, and solvent recovery, is also discussed, likewise the nature and uses of bleaching clays, diatomaceous earth, silica gel, ion exchangers, and adsorbents used in chromatography. Finally, brief descriptions of the sources and characteristics of domestic and foreign carbons and of other commercial adsorbents are presented in the alphabetical order of trade names. This introductory chapter makes very interesting reading, not only because of the scholarly treatment of the scientific and technical aspects of the subject but atso because the human side has not been neglected by the author. There are some delightful life sketches of the chemists and engineers who have played a prominent part in the development of the sugar-refining industry in the United States during the past hundred years or so. The bibliography proper, comprising 805 pages, contains 6002 carefully prepared abstracts of scientific and technical articles on solid adsorbents which have appeared in the literature from 1900 through 1942. I t is divided into seven chapters. each headed by a brief introduction defining the arrangement and scope of the material considered in it. Chapter I (196 pages, 1386 abstracts) deals with the adsorption of gases and vapors on carbons, metals, inorganic compounds including zeolites, glass, quartz, silica gel, other porous oxides, clays, and soils; adsorption on textiles and organic materials in general is not considered unless the paper is of unusual interest. Chapter I1 (pages 197-348, 1105 abstracts), on adsorption from solutions, is subdivided according t o solvents, whether inorganic or organic, and according to adsorbents, whether carbon or noncarbon. Papers on ion exchangers and on chromatographic adsorption are also included in this chapter. Chapter 111 (pages 349-373. 176 abstracts) takes up heats of adsorption and heats of wetting. Articles on the various theories of adsorption are abstracted in chapter IV (pages 375431,456 abstracts). Chapter V (psges 433-688, 1985 abstracts) takes up the uses of carbons and of miscellaneous adsorbents in the sugar and other industries, in medicine. pharmacy, and agriculture. Papers on carbon catalysts are also placed in this chapter. Reviews, general papers, and articles on the chemical and physical properties of solid adsorbents and their determination are abstracted in chapter VI (pages 689-767, 624 abstracts). Chapter VII (pages 769-805, 270 abstracts) deals with methods of preparation of carbons from animal, mineral, and vegetable sources. Complete author and subject indexes, with abundant cross references in the latter, greatly facilitate the practical use of the book, which provides the investigator in the field of adsorption and adsorbents with a gold mine of readily available information. The author makes no claim for completeness. Many articles
that are only of secondary or collateral interest have been omitted t o save space. It is unfortunate that the patent literature had t o he left out entirely, and it is hoped that the author will a t some future date compile a cornpan& volume of patent abstracts. Only a small number of typographical m r s , usually in the spelling of foreign words, have been noticed. Paper, typography, and binding are first class. The b w k is warmly recommended not only t o those who are directly interested in the industries where solid adsarhents are used, but t o researchers in this and allied fields. A need for it has been felt for a long time. F. W. ZEREAN NBW YOEX SUGARTRIDSLIQORATOPY, IAC. Nsw Y O ~ C.TY K
VALENCY:CLASSICAL IWD MODERN. W. G. Palmer. Fellow of St. John's College, Cambridge; University Lectu~erin Chemistry. The University Press, Cambridge, England, 1944. ix 242 pp. 59 figs. 43 tables. 13.5 X 21.5 cm. 8 . 5 0 . The aim of this book on valence is set forth on its iacket: "The f i r ~ tfour chapters present a compact elementary accounc of clairical nnd modern conceptions of valency, suitable for the general rmder and for students preparing for university ernminations. The concluding chapters are more advanced; chapter five shows how the electronic theory is applied t o the heavier elements and their principal compounds; and the last chapter is devoted to current developments, and theories still in their early stages." The hook is well organized and well written. The first chapter is a very interesting historical introduction. I n some histories of chemistry, one gets the impression that the long delay in accepting Avogadro's hypothesis (1811 t o 1858) was due largely t o ignorance. According t o this book, it was due primarily to the opposition of Dalton and Berzelius. In spite of such eminent opposition, Dumas had accepted the hypothesis as early as 1827, and Prout by 1834 regarded it as proved! His rather unusual method of treating the subject is set forth by the author in these words: "It is intended in this Section t o take the elucidation of structure as far as modern experimental methods will permit, but t o defer presenting the solutions of the numerous problems so raised until after the discussion of the electronic theory in the later chapters. It is hoped that this separation will more clearly define both the problem and the current explanation, and by emphasizing the permanent insistence of the former and the power (and defects) of the latter lead t o the clmrer understandina of both." This h o ~ eseems t o be justified by the finished product. I t is one of the best books in its field. The author's attemnt t o exnlain auantum numbers and atomic orbitals- without mine into mathematical -~~~ - ~detail ~ - renrez-sents a real advance in chemical education. His illustrations and examples are good. This one is particularly a p t : "To the nonmathematical the conception of resonance hybrids is a difficult one, especially as there is no obvious manner of pictorial representation. A very simple but crude analogy may prove helpful. Suppose a printer is asked t o produce a handbill in green color, a t short notice. He discovers t o his consternation that he has exhausted his green ink but is well supplied with blue and yellow. He. therefore. carefullv over-mints a blue bill with the vellow ink, am1 will, if his 'repistration' ii nicc enough. not raise a n y doubls in his rllstnmu that the normnl printing i t , green ink has been carried out." This review provides an opportunity t o register a protest against the habit the "English schwl" has of writing coordinate or dative bonds as if each atom involved were an ion. Professor Palmer even calls such covalent bonds by a new name, the "eo-ionic" bond! The habitual writine of coordinate bonds with charges attached is cumbersome, misleading, and unnecessary. It is not helpful t o the expert and is most certainly confusing to students.
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