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PROBLEM BOOK FOR GENERAL CHEMISTRYBy R. H. LERoY, Agricultural and Mechanical College of Texas. Ready for fall classes.

A supplementary problem book for general chemistry courses, this manual offers a selected number ofthe important problem types in a simple, direct, and orderly presentation. The continuity and general-ity of problems is revealed throughout the book. An introductory section provides a brief review of thefundamental operations of arithmetic.

PRINCIPLES OF QUANTUM MECHANICSBy W. V. HOUSTON, Rice Institute. International Series in Pure and Applied Physics. Ready inDecember.

Provides the student with an understanding of the uses of quantum mechanics in the various fields ofphysics. Contains a deductive presentation of the wave mechanics form of quantum mechanics and in-cludes a general outline of the basic theory developed from two fundamental postulates, followed by aseries of illustrative applications.

THE CHEMISTRY AND ACTION OF INSECTICIDESBy HAROLD H. SHEPHARD, U. S. Department of Agriculture. 496 pages, $7.00.

An authoritative text and reference, this book is concerned with the properties of insecticides, ratherthan the details of insect control, and includes the essential facts and theories regarding the chemical,physical, and toxicological aspects of insecticides, as well as their effects upon insects, plants, and higheranimal life.

HEAT AND THERMODYNAMICS. New 3rd editionBy MARK W. ZEMANSKY, College of the City of New York. Ready in October.

The first ten chapters of this successful intermediate text deal with the fundamentals of the subject,including the concepts of temperature, heat, internal energy and entrophy, and the first and secondlaws of thermodynamics. The remaining nine chapters deal with physical, chemical, and engineeringapplications.

Send for copies on approval

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August 17, 1951

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SCIENCE, Vol. 114

So... 3919

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SCIENCE, Vol. 114

PHOTOVOLTLine-Operated ElectronicMULTIPLIER-PHOTOMETER

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SCIEXCE, Vol. 114

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TOM AND ARLENE HADLEY, anature team, have appeared through-out the nation on Audubon ScreenTour lectures. They are shown here re-cording the songs of birds with the aidof a parabolic sound reflector. For-merly a General Motors executive, Mr.Hadley has infected thousands withhis enthusiasm as a naturalist, wild-lifephotographer and philosopher.

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WRITE FOR FREE CATALOG. 32pages of useful information you shouldknow before you buy any binocular.Tells how to select a glass for yourown use. Bausch & Lomb Optical Co.,642-12 St. Paul St., Rochester 2, N. Y.

SCIENCE, Vol. 1148