ing." and "Lead Products in Industry." The latter will he of particular interest t o chemistry teachers. May R. Mayers has contributed the excellent chapter,"Treatment of Lead Poisoning," where prevention is keynoted in her description of proper design of buildings and equipment, maintenance of safe conditions, and of specificaUy clear methods for the advice and instruction of all sorts of personnel in lead industries. Then follows a discussion of medical supervisory methods, specific curative measures, and symptomatic treatment. The 6nal chapter, "Procedures for Determination of Lead," hv Morris B. Tacohs will delieht analvtical chemists. The ore* cautions necessary for accurate determinations of small amounts of lead are painstokingly emphzsized. The descriptions of qualitative and quantitnlive nwthods are sufficiently complete to allow an accurate estimate of the facilities, equipment, and techniques required for their conduct. Of course, the analyst will wish t o consult the original literature before performing such critical analyses in an official capacity. Alternative procedures are given, i. c., lead sulfide, s-diphenylcarbazide, dithizone colorimetric and photometric, and a polarographic method. Among the eight minor errale are "numberous" on p. 74. "endentulous" o n p . 77, "suddenlly" an p. 105. and "(000)" instead of "(226)" as a cross reference on p. 222. The thoughtful reader of even a small part of this volume will feel an innease in his cautious respect far lead as a leading potential hazard t o the health of man and all animals. DAVID LYMAN DAVIDSON
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onance energies, and resonance as related to coplanarity of atoms, interatomic distances, dipole moments, and molecular spectra. These chapters, which consume 163 pages of the hook, lay the foundation for an adequate understanding of resonance. The remaining two chapters discuss the applications of the concept to the two main problems of theoretical organic chemistry, namely. chemical equilibrium and chemical kinetics. The last chapter is the longest one of the book (64 pages) and contains the material of greatest interest t o organic chemists. Despite the fact that this hook is far from the first todiscuss the resonance theory in nonmathematical language and t o illu5trat.e its application t o organic chemistry, i t merits t h e enthuslastre acclaim of the chemical profession, partly because i t is more up to date than the earlier hooks in the field but chiefly because Dr. Wheland's intimate knowledge of the mathematical details of auantum mechanics has enabled him t o m i t e niticallv, on the qualitative aspects of the thmry of resonance which arc the allimportant aspects in dealing with the complicated molceulcs peculiar to organic chemistry. A. Eownnn RaaarcK ~~~~~
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WAYNEUNIPBISZTX D B ~ O IMICB~DAN Z,
A I . m o u r o ~ u Pnooaan F U R GENERAL CI~MISTILY. I . R. .lforlon, D .K C'lippinxrr, I.. P. Eblin. Ohio University. m d e r the editorshin of Hrrrnon T. Brircop. Profrswr of Chemistnr. Indiana ~ n & s i t y . Houghton ~ i f f l i nCompany, ~ o s t o i ; 1944. vi 272 pp. 17 figs. 21.5 X 28 cm. Paper bound. punched, detachable leaves. $2.00. This laboratory manual consists of (1) 28 experiments in general chemistry and (2) qualitative analysis for the identification TEE THEORYOF RESONANCE AND ITS APPLICATIONS TO ORGANIC of 24 cations and 22 anions. Each experiment is designed t o CHEMISTRY.George Willard Wheland. John Wiley and Sons. teach a principle thoroughly, and not merely t o extend the deInc., New York, 1944. vi 316 pp. 13.5 X 21.5 cm. $4.50. scriptive laboratory work of the secondary school. A clear disIt is probably safe t o say that the modern qnantum-mechani- cussion introduces each experiment, observations are recorded on ral t o a separate sheet a t indicated points in the procedure, and the -~~~viewooint has revolutionized the theoretical aonroach .. chemistry irr most of its dcp:rrtments. This is particularly true principle of the experiment is summarized in a set of searching of that quanthm-mechanical concept known as resonance. Al- questions. The analytical portion is designed for macro techthough the theory of resonance with itsapplications to both inor- nique, but the procedure can be adapted t o semimicro. Special ganic and organic chemistry has been frequently and extensively tests for identifying cations are also included. expounded by various authors, i t certainly has not been more sucInstructors in general chemistry and in qualitative analysis will cessfully treated in relation t o organic chemistry than in Dr. find here a well-organized and tried-in-service set of laboratory diWheland's hook. rections. The subject matter of the book is strictly limited t o the field of ELBERTC. WEAVER Tesonance, the excursions into related fields heing made only when P A ~ L ~ ACADBMY PB ANDOVGR, M*SSACB~SBTIS they throw light on this main subject. This means inevitably that some points of very great interest t o theoretical organic chemistry are not included; but it also means t h a t commendable AN OUTLINEFOR INDUSTRY. Frederick Willkic and Harrison C. unity is achieved, which aids the reader in understanding this Blenkmeyn. Charles C Thomas, Publisher. Springfield. Illisubtle subject. The hook is also characterized throughout by nois, 1944. xiii 260 pp. Illustrated. 14 X 22 cm. $4.00. clarity of style. Mare or less a "olua" for the distillerv industrv. ..but in alarxer Dr. Wheland's approach, although necessarily dogmatic in or- sense, just what the iitle impliesso& general philosophy ?or der t o avoid mathematical difficulties, is nevertheless critical. industry, in which the authors draw upon the experiences of the Indeed the outstanding features of his monograph are the care distillers. with which he assesses the reliability of various experimental methods and theoretical conclusions and the nicety with which be DYES. WilIWn F. Leggett. Chemical distinguishes between closely similar concepts such as binding ANCIENTAND MEDIEVAL Publishing Company, Inc., Brooklyn, New York, 1944. vi energy and hond energy, resonance "structures," and molecular 95 pp. 13 X 19 cm. $2.25. structures in the ordinary chemical sense, etc. As examples of This hook describes the discovery and development of dyes by his critical care, one might cite a t random such instances as his discussion of the limitations of the Debve for diode ancient people. Coloring matter was a necessity t o primitive . . ecluation . man because it was f i s t used as a form of magic. morncnts, h~seraluationof the rrlative accuracy of methods u u d Many kinds of shrubs, trees, berries, and nuts were the first for the deternminatwn of reannnrc energies, his warning that "the frequently cncountrred statement tbat re,onanrr ' jhurrens' hond sources of dyes. Trade in dyestuffs began when the sources of distances is not quite strictly correct," his care in pointing out one district were found t o he superior t o another. Gradually the that resonance considerations are related to changes in internal more inferior dyes were eliminated until in medieval times the energy ( AE) and not to changes in free energy ( A F ) as many or- main sources were the following: madder, indigo, woad, saffron, ganic chemists seem t o have assumed, and his explanation that safflower, weld, hrazilwood, logwood, barwood, camwood, the resonance is not a physical reality but merely a mathematical fustics, orseille, cudbear, annatto, turmeric, cutch, gambir, quercitran, Tyrian purple, kemes, cochineal, lac, malachite, iron, convenience. The book opens with a quick plunge into the quantum-me- azurite, carbon, and chalk. Dyes made from these substances chanieal features of resonance. This is followed by chapters on are discussed under three headings: vegetable, animal, and the different types of valence bonds, methods of calculating res- mineral.
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