SCIENCE-ADVERTISEMENTS

Ioe #e ORGANIC CHEMISTRYA BRIEF COURSE IN ORGANICCHEMISTRY

By REYNOLD C. FUSON, RALPH CONNOR, CHARLESC. PRICE and HARoLD B. SNYDER

An elementary textbook and laboratory manual.The fundamental concepts and the more importanttypes of organic compounds are discussed as earlyas possible, and are constantly used throughout theremainder of the book.

1941; 248 pages; 6 by 94; $2.50

ORGANIC CHEMISTRYBy REYNOLD C. FUsoN and HARoLD R. SNYDE

Designed for introductory courses, the material isdivided into two parts. Part I covers the prin-cipal types of organic compounds, and Part II themore advanced aspects of these compounds, withparticular emphasis on the use of organic reactionsin synthesis.

1942; 506 pages; 6 by 94; $3.50

ORGANIC CHEMISTRYBy HENRY GILMAN

New in this edition are: the reactions of aliphatichydrocarbons; synthetic polymers; catalytic hydro-genation and hydrogenolysis; organic sulfur com-pounds; aliphatic fluorides; the chemistry of theporphyrins; chlorophyll; and the redistribution re-action. In two volumes, available separately.

Second edition; 1943; 2096 pages;6 by 94; $7.50 per volume

AN INTRODUCTION TO ORGANICCHEMISTRY

By IRA D. GARARD

A revised and somewhat enlarged edition of a well-known book for brief introductory courses. Thesimplicity of the laboratory apparatus and manipu-lation has been retained.

Second edition; 1940; 389 pages; 6 by 94; $3.00

AN INTRODUCTION TO ORGANICCHEMISTRY

By the late ALEXANDER LOWY, BENJAMIN HAR-Row and PERCY APPELBAUM

This new edition, with 50 additional pages, coversrecent developments and emphasizes the connectinglinks that bind organic chemistry to medicine, den-tistry, pharmacy, and other biological sciences.Sith edition; 1945; 448 pages; 51 by 81; $3.50

TEXTBOOK OF ORGANICCHEMISTRY

By GEORGE HOLMES RICHTER

A comprehensive, teachable book, revised to includecurrent subjects of importance. Excellent as thefoundation for a solid course for beginning stu-dents.Second edition, 1943; 760 pages; 6 by 94; $4.00

LABORATORY MANUALSLaboratory Outlines and Notebookfor Organic Chemistry

By CECIL E. BooRD, WALLACE R. BRODE andROY G. BOSSERT

1940; 241 pages; 84 by 104; Paper; $1.75

Laboratory Book of ElementaryOrganic Chemistry

By the late ALEXANDER LOWY and WILmE E.BALDWIN

Second edition; 1934; 182 pages; 81 by 114; $2.50

Laboratory Manual of OrganicChemistry

By HARRY L. FISHERFourth edition; 1938; 412 pages; 51 by 81; $2.75

Laboratory Manual of ElementaryOrganic Chemistry

By GEORGE HOLMES RICHTER1940; 128 pages; 6 by 94; $1.25

The Systematic Identification ofOrganic Compounds

By RALPH L. SHRINER and REYNOLD C. FUSONSecond edition; 1940; 312 pages; 6 by 94; $2.75

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SCIENCE-ADVERTISEMENTS

"A more-than-adequate text.. ."

In writing this new volume, theauthor, a successful teacher for manyyears, has kept the student constantlyin mind. Fundamentals as well as

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SCIENCE-ADVERTISEMENTS'

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In February, 1945, Science inaugurated a classified advertising section under the titleIn The Market Place to carry short notices about supplies, equipment, books, and positionsopen and wanted. Nearly a year has passed and the use which the readers have made ofthis section amply justifies its continuance. Now, in recognition of the growing need forone central location which can be used by all scientists and the universities and industrialorganizations for personnel matters, Science announces that it will begin a separateclassified section in the March 1, 1946 issue known as Personnel Placement. In The MarketPlace will continue as a companion section for announcing needs for and availability ofmaterials, supplies, and books. The rates for both sections will be the same, 10 cents aword, with a minimum of $2.00, cash with order.

Many scientists are now being demobilized from the armed forces. Coincident withthis, the colleges and universities, because of unprecedented enrollments, are facing an'acute shortage of instructional personnel. Industry, too, has great need for scientificpersonnel for the development of new products. Science because of its wide circulationand wide coverage of all branches of scientific activity is a logical medium for publicizingnotices of positions open and wanted.

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All orders and copy to be inserted in the first issue of Personnel Placement must reachthe Association's Advertising Department, Massachusetts and Nebraska Avenues, N. W.,Washington 16, D. C., not later than February 15, 1946.

12 Vol. 103, No. 2666;

SCIENCE-ADVERTISEMENTS

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THE VERTEBRATE. EYEby Gordon L. Walls

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deserving of the highest commendation . . .

a standard reference wherever and wheneverinformation on the eye . . . is needed." L.B. AmEY, in Anatomical Record.

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`Never before has so much light been shed atone time on an animal organ. . ." CARL L.HUBBS, in American Naturalist.

785 pages, 483 illustrations, 3 in color.

$6.50 postpaid.

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Notice to Subscribers and ContributorsCommunications relative to articles offered for publication

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Communications relative to membership in the Associationand to all matters of business of the Association should beaddressed to the Permanent Secretary, A.A.A.S., SmithsonlanInstitution Building, Washington 25, D. C.

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I N TH11E M A R K E T P L A C ERATES to be paid in advance. Regular setting 10¢ a word, minimum charge $2.00 each; count 8 words if a box address is used.Diplay, a inches maximum, $8.80 per column inch. No discounts or commissions.SEND advertisements with remittance to the ADVERTISING DEPARTMENT, American Association for the Advancement of Science,AMERICAN UNIVERSITY, MASSACHUSETTS AND NEBRASKA AVENUES, WASHINGTON 16, D. C. Correct remittancemust accompany instructions and copy and advertisements will be published in sequence of completed orders.

REPLIES to box number advertisements should be sent to the Advertising Department for forwarding.

SUPPLIES AND EQUIPMENT

¼y Discs for the Assay of Penicillinand other Antibacterial Substances

No. 740-E.

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For Sale-Metal file and stand with 24 sliding frames eachholding 49 lantern slides 3x4. DR. IRA I. KAPLAN, 755Park Avenue, New York 21, N. Y.Ultra Centrifuges-airdriveti, quantitative, analytical varioustypea or own specifications. Jos. Gazansiaza, 454 FeltonDrive, Menlo Park, California.

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POSITIONS WANTED

BELGIAN ENTOMOLOGISTWants to work in Europe for an American institution.Twenty years experience on entomological and speological(Cavernicoles) researches. Can furnish highest refer-ences. Correspondence invited and may be initiatedthrough Box 350, SCIENCE.

Bacteriologists, Biologists, Physiologists, Chemists, Pharma-cologists, Physiotherapists, Laboratory Technicians, let uShelp you secure a position. Our service, estblished 189,is nationwide. Write us today. All iuformnation contidential.AZNOE'S-WOODWARtD BUREAu, 30 North Michigan. Chicago 2.Biologist, 45, Ph.D., Brown University; genetics. Fourteenyears' college teaching, several publications. Desires posi-tion which will include teaching genetics. Available Sep-tember, 1946. Box 344, SCIENCE.Organic Chemist, Ph.D. Desire teaching position in smallcollege or university. At present engaged in industrial re-search-directing the research activities of small group ofchemists and technicians. Ejcellent academic and industrialrecord. Good background in physics and mathematics. Age30. Box 343, SCIENCE.General ZoologIst-Ph.D. desires teaching or research posi-tion. Experienced teacher. Most of training in generalphysiology and invertebrate zoology. Sigma Xi. Age 30;single; will go anywhere. Now on terminal leave after 3years Army service as Aviation Physiologist. Minimumsalary $2,500. Box 342, SCIENCE.Opportunities Wanted-Chemist; B.Sc. (science, mathemat-iCs), M.Sc. (analytical chemistry, physical chemistry), Ph.D.(physical chemistry, analytical chemistry); four years re-search in analytical and physical chemistry; eight yearsteaching experience; for further information please writeBURNEICie LARSON, Director, The Medical Bureau, PalmoliveBuilding, Chicago UL

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American Association for the Advaneementof Science ........ ........... Cover 2 and 12

American Optical Company ................... Cover 4

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University of California Press... Cover 2

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18 Vol. 103, No. 2666

To measure is to knowTwenty-five years ago, one standard of sound powerwas the ticking of a watch, another was the click-ing of two coins; and the measure was how faraway the tick or the click could be heard. Thattest was made in measuring people's hearing, a fieldof interest to the Bell System scientists because theear is the end-point of every talking circuit.

Accustomed to exact measurements, Bell scientistsproceeded to develop a method of measuring hear-ing-sensitivity in terms which could be preciselydefined and reproduced. After plotting hundredsof runs like those above, they decided on a partic-ular sound intensity, representing an average "thresh-old of hearing," as a starting point.

Sounds delivered by a telephone line had beenevaluated by listeners who compared their loudnesswith that of a standard source. There were widevariations in ears, so engineers replaced them byelectrical instruments. -When later their associatesdeveloped the Western Electric radio and publicaddress systems, measuring circuits were promptlyforthcoming. A noise meter followed, used in quiet-ing airplanes and automobiles."Through measurement to knowledge," said a

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