JOURNAL OF CHEMICAL EDUCATION
532 lioeraohv has been increased from the 200 of the first edition to
sections on basic theory, injection of the economic approach to absorber design, and thorough revision of the original material in the first edition has resulted in the production of a new book, rather than a new edition. The book is exhaustively thorough, comprehensive, and-to date of publication-complete. "Ahsorption and Extraction" will serve as an excellent sonrce book for both researchers and engineers in the many fields of interphase diffusional operations. BERNARD J. LERNER
THFUNIYER~ITI or TEXAS ADBTIN.T B X * ~
multiple bonds, the nature of conjugation, the conductance of metals, the absorption of light, and many other phenomena more readily than does the valence-bond theory. Despite the difficulty of wading through the murky m a t h e matical equations, there is much knowledge that chemists can gain by reading this book. The author is careful to point out many misconceptions that have been current as s result, primarily, of attempts by the uninitiated to visualize the valancebond treatment. The author has a knack for explaining shstruse points, as for example in his discussion of the contrihution of atomic dipoles to dipole moments. Largely because there are fen-er equations, the last half of the hook is easier reading than the first half. A formula index of subdances is provided in addition to the axthor and subject indexes. CARL R. NOLLER STANFORDU N ~ B R J I T Y
STANFORD.C&LIPORNIA
VALENCE C. A. Coulson, Rouse Ball Professor of Mathematics in the Univer6ty of Oxford. Oxford University Press, New York, 1952. vii 338 pp. Illustrated. 21.5 X 14 cm. $5.
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INTHE opinion of this reviewer, no one has done more to popularize the maleculsr orbital theory of valence and its application t o organic chemistry than C. A. Coulson through his review articles in the Proceedings of the Royal Society of Edinburgh, in Endeavour, and in the Quarterly Reviews of the Chemzcal Society. Hence it was expected that his new hook, "Vden.lenee," would be written in sueh a way that most chemists could understand i t without difficulty. This hope was fostered by the statements in the Preface that students of chemistry "should be sufficiently acquainted with the chief ideas and the essential tools that lie behind the modern theory of valence" and that "practioally no mathematics is needed far this purposo, since almost everything necessary can he put in pictorial terms." This promise is not fulfilled. The disou~sionis almost wholly in the form of mathematical equations. I t abounds in unfamiliar symbols and in terms sueh as Hamiltonian operator, secular equations, orthagonality, wave function, overlap integral, linear variation function, and matrix component. The author's implication that "practieslly no mathematios" is used in his disousrian ~houldnot make the American reader feel inferior. No one whois not working in the field or whois not fresh from a study of wave mechanics would he able to follow the mathematical portions of the discussion with understanding without a great deal of digging. Although "mathematics is a language" it is not the native tongue of moat chemists, and those who have arrived a t useful conoepts by means of mathematics and who wish to spread the knowledge of their results must tran~latethem into familiar speech. The argument frequently heard that the only way to express these results precisely is in the form of mathematical equations may be technically correct, but even the mathematician undoubtedly hss some picture in mind, because he is quick t o point out errors in pictures visualized by the chemist. I t is the mathematician's pictuve that most chemists want. and they are quite willing to accept it on faith. Concerning t h e content of- the bonk; the moiecular-orbital treatment is compared side by side with the valence-bond treatment of diatomic molecules, polyatomic molecules, hyhridization, conjugated and aromatic molecules, nonmetallic solids, metals, the hydrogen bond, and hyperomjugation. The conclusion is that bath treatments usually arrive a t the same result but that the quantitative calculations of certain properties, such as the net charge on an individual atom in a molecule, can be made with less difficulty by the molecular-orbital method. However, mast readers would he willing to leave these aspects of the theory of valence to the expert. What is obvious but not emphasized is that the moleeular-orbital theory enables the nonmathematiedly minded reader to visualize the source of bond energy, the nature of directed valence, the cause of restricted rotation about doublo bonds, the high reactivity of
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DANA'S MANUAL OF MINERKLOGY
Revised bv Cornelius S. Hurlbut. Jr.. Associate Professor of a in era log;, Harvard. S~xteenthektion. John Wileg & Sons, 530 pp. 471 figs. 14.5 X 22 cm. Inc.. New York, 1952. ~i $6. THE several Dana hooks on mineralogy range from the level of the amateur to that of the professional mineralogist. The "Manual" is pitched a t the level of s. oollege student in his first mineralogy course. An indication of its popularity in this use is the fact that it is now in its sixteenth edition. The first edition was by James Dwight Dana in 1848. The main changes introduced in the present edition are a n enlargement of the section on the aims and scope of mineralogy, a change in crystallographic terminology to agree with modern usage, the listing of Hermann-Manguin symbols for symmetry classes, and a new section on crystal chemistry. Crystallography is treated from a morphological point of view. Symmetry, axial ratio, parameters, and Miller indexes me explained and the various crystal forms are defined. Physics1 properties are then disoussed. The chapter on chemical mineralogy includes discussions of chemical bonds, atomic packing,
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approximately 264 minerals. Each mineral is ddescribkd under the headings: crystallography, physical properties, composition, tests, diagnostic featurm, alteration, occurrence, use, name, and similar species. Succeeding chapters refer to geologic occurrence and economic uses. There are finally a set of determinative table^, a general index, and a mineral index that lists the main propertier. The book rightly points out that future progress in mineralogy will probably be in the direction of relating properties and acrurrences of minerals to their internal structure. The new seetion an crystal chemistry is a step in this direction. These principles of erystsl chemistry are very Mtle applied to specific minerals in this hook, however. Presumably the author believes that the first course in mineralogy should aim primarily a t trsining the student in simple methods of identification of the more important minerals. With such training the student can identify minerals in the field for the purpose of making geological interpretations. Later courses, using more advanced textbooks, will deal with such methods of identification as optical properties and X-ray techniques and with the application of crystal chemistry to minerals. The new edition of Dana's "Manual of Mineralogy" is recommended as a good straightforward textbook for a college introductory course in mineralogy. I t stresses identification and nlao premnts basic principles an which further progress can be made. ALONZO W. QUINN BROWNUNIVER~ITT P n o v x n m ~Raom ~. Isr.*Nn
