444Q-ewe&t/e e

Science Writing Awards

In this postwar world, science has amajor role. Some look to science toalleviate or eliminate disease . . . someexpect it to ensure and guarantee a per-manent peace . . . still others expect thedevelopments of science to unfold a newera of sustained economic prosperity.The broad attainment of these goals de-mands a well informed public. Sciencemust be intelligently, accurately andmeaningfully explained to the layman sothat he may understand its possible con-tributions and also its limitations in ref-erence to problems of human welfare.

The Westinghouse Educational Founda-tion and the Ameirican Association forthe Advancement of Science feel thatspecial encouragement should be given tothe writers who accept the responsibilityof interpreting scientific research andprogress to the public. Believing firmlyin the worth-whileness of this objective,the Foundation and the Association havejoined together for the sponsoring andadministering of the AAAS-George

Westinghouse Science Writing Awards.The fourth series of Awards and the 1948competition period are now being an-nounced.

Two $1,000 prizes will be given-one fornewspaper and one for magazine sciencewriting. Citations for distinguishedjournalism will be awarded to the publi-cations sponsoring the winning articles.The competition period is from October16, 1947 to July 31, 1948 for newspaperstories and from October 1947. throughJuly 1948 for magazine articles. Allentries must reach the Managing Com-mittee on or before August 7, 1948. Thearticles must have been published ineither a newspaper or magazine of gen-eral circulation within the continentallimits of the United States. The award-ing of the prizes will take place duringthe Centennial Celebration of the As-sociation in Washington, September13-17, 1948.

For complete information, rules and entry blanks write to

The Chairman of the Managing CommitteeAAAS-George Westinghouse Science Writing Awards

1515 Massachusetts Avenue, N. W.Washington 5, D. C.

9

0 02 IMILVEMA

mWIMP, RMWIMMM Ewwwwwmsnr wm

Illustrated is the Taylor Model T-O pH Comparator-basic set of the Taylor line. All pH slides andmany others may be used on this base. In makinga determination, the prepared sample is placed in themiddle tube in the base, the slide moved across untilthe colors match, and . . .

FAST. EASYpH and CHLORINEDETERMINATIONS

with

TAYLORCOMPARATORSThe all-important determination of pH in manufac-turing and processing chemicals is merely a matter of60 seconds with the Taylor Comparator. Because oftheir accuracy, simplicity of operation, durability, andlow cost, Taylor Comparators are recognized through-out industry as a dependable standard for colorimetricdeterminations. All Taylor Liquid Color Standardscarry an unlimited guarantee against fading.Nine Taylor Color Standards, a complete set for eachindicator or determination, are enclosed in one plasticslide-no handling of single standards.Many Color Standard Slides may be used with onebase each set is completely portable.

VALUABLE BOOK FREEIc!P-o k Write direct for "Modem pH and

Chlorine Control?' 96 pages ofI-Ad w latest methods and equipment,

FREE. See your dealer for equip-ment.

IKlett made *Glass Absorption Cells

Fused under high temperature with acid, alkali and othersolvent resisting cement. Optical flat walls. Many stock sizes

Special requirements made to orderSole manufacturer In the United States of fused Eleotrophoresle *die

Makers of complete Electrophoresis ApparatusKLETT SCIENTIFIC PRODUCTS

Klett.Summerson Photoeleetrie Colorlmeters. Colerlmoten,Nephelometers, Fluorimeters, BOO Colorlmeters. Electrb -phoresis Apparatus, Glass Standards. Kltt Reaents

Klett Manufacturing Co.179 East 87th Street, New York, New York

ARGONHELIUMKRYPTON

XENONand Standard or Special

MIXTURESLINDE rare gases are spectroscopically pure-argon,helium, neon, and standard mixtures are availablein one- and two-liter glass bulbs and in cylinders;xenon and krypton are available in liter andfractional-liter bulbs.

The word "Linde" is a trade-mark of

S".". ; a " ,

10

.1

%or'

M lE WILY---~ ~ ~~ ~ ~ ~~~ ~ ~ ~ ~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~

New Wiley books for study and referenceTextbook of Geology, Part I

PHYSICAL GEOLOGYThird Edition

by CHESTER R. LONGWELL, Henry Barnard Davis Professor of Geology; ADOLPH KNOPF,Sterling Professor of Physical Geology; and RICHARD F. FLINT, Professor of Geology. All atYale University.

The new Third Edition has a completely new chapter, "The Method and Scope of GeologicStudy," covering the scientific method, the continents, movements of the crust, the contest betweeninternal and external forces, and the time-factor in geology. About 25 new illustrations have beenadded to the already excellent selection included in earlier editions. Each of the many reading ref-erences is described briefly, to allow a more exact choice of extra study. Text matter is concise; allmaterial considered unnecessary for an introduction to geology is excluded from this edition.Ready in August Approximately 603 pages Probable price, $5.00

Introduction to

GENETICS AND CYTOGENETICSby HERBERT P. RILEY, Professor and Head of the Department of Botany, University of Kentucky.

This book features the chromosomal approach to the study of genetics. Beginning with a discus-sion of cells, the book goes on to discuss chromosomes and genes. Mendelian inheritance is consid-ered as a function of chromosome behavior. All material in the text is presented logically ratherthan chronologically. An extensive discussion of blood groups is included, as well as some elementarybiology, specifically for review purposes. Numerous figures, many of them never published in anyother book, illustrate almost every page of text. A large bibliography is given for every chapter.February 1948 596 pages $5.00

DETOXICATION MECHANISMSby R. T. WILAMS, Senior Lecturer in Biochemistry, University of Liverpool, England.

Detoxication Mechanisms gathers together in logical order the available information on the meta-bolic fate of organic compounds foreign to the body. The book aims to make it possible for theworker to advance suitable working hypotheses. It covers the metabolism of: aliphatic compounds;cyclohexane derivatives; aromatic hydrocarbons; halogenated aromatic hydrocarbons; phenols; aro-matic alcohols, ethers, aldehydes, ketones, amides; aromatic acids; organic cyanides; aromatic nitro,amino and azo compounds; sulphones, sulphonic acids, sulphonamides; terpenes, camphors; hetero-cyclic compounds; organic compounds of arsenic.February 1948 300 pages $5.50

Dissociation Energies and Spectra ofDIATOMIC MOLECULES

by A. G. GAYDON, Warren Research Fellow of the Royal Society, D.Sc. (Lond.).Dr. Gaydon clears up some of the inconsistencies and unsolved problems in the determination of

dissociation energies. The approach is mainly from the spectroscopic viewpoint, but two chapterscover determinations by thermal methods and by controlled electron impact. This is one of the veryfew books, if not the only one, to give a rounded account of this theory. It includes the author 'sown contributions to the subject, and a summary of numerical data. The last chapter is a collectionof data for about 250 diatomic molecules, many of which are carried to a higher degree of accuracythan ever before, and which have never been published previously.February 1948 239 pages $5.00

JOHN WILEY & SONS, Inc., 440 Fourth Ave., New York 16, N. Y.

11

bh-

Second AnnualInternational

Photography-in-Science Salon,

Sponsored by

THE SCIENTIFIC MONTHLY-SMITHSONIAN INSTITUTION

Accepted entries will be shown fromSeptember 1 to 21, inclusive, in the Nat-ural History Building, U. S. NationalMuseum, Washington, D. C., and subse-quently in museums throughout thecountry.

For information and entry blanks,write to

The Editor

The Scientific.Monthly1515 Massachusetts Ave., N. W.

Washington 5, D. C.MEMBERSHIP IN THE AAAS NOT A

REQUIREMENTNO ENTRY FEE

I,

WRITE FORBULLETINNO. 690-SC

HELIGIE

FOR SOL4REACTION

Phosphorus * Potassium * Cal-dum * Magnesium * NirateAmmonla*Sulphaft*CeOIlode

Hellige.Troug Testers havegained universal acclaim be-cause they are based on soundscientific methods and are highlyaccurate. They have won thesponsorship of the foremostauthorities on soil chemistry andthousands of testers are used byU.S. Government Agencies, aswell as by professional andamateur gardeners.

3718 NORTHERN BLVEN *. LONG ISLAND CITY 1.N.Y.-

s e e

-1--- -- -----

You get UNIFORM, ACCURATE results with the

I

PRECISION INCUBATORPrecise performance is essential in any incu-bator used in bacteriological work . . . andprecise performance is the outstanding featureof all Castle Precision Incubators.Independent laboratory tests proved these

two important facts:UNIFORMITY, + Ys8°C. Never as much as adegree variation between top and bottom ofchamber when loaded.CONSTANT TEMPERATURE, + V21e to ¼14C.Never more than a fraction of a degree varia-tion at the thermometer*. . despite roomtemperature fluctuations.For full details, see your Castle dealer or

write: Wilmot Castle Company, 1212 Univer-sity Ave., Rochester 7, N. Y.

I12

g

FUNDAMENTALS OF HUMAN REPRODUCTION

By EDITH L. POTTER, M.D., The University of Chicago. McGraw-Hill Series in Nurs-ing. 230 pages, $3.50Dr. Potter describes, clearly and authoritatively, the most important aspects of humanreproduction and prenatal development. The illustrations are a unique feature of thebook. There are over 100 line illustrations, all reproduced from original drawings pre-pared especially for this book by Alvin Meyer, F.A.A.R. In addition, there are 13photographic plates of exceptional quality and interest.

VIBRATION AND SOUND. New second edition

By PHLP M. MORSE, Director, Brookhaven National Laboratory. International Seriesin Pure and Applied Physics. .466 pages, $5.50

The revision of this outstanding text represents a thorough, up-to-date treatment of thetheory of vibration and sound for students of physics and communications engineer-ing. The major changes and additions in the new edition are concerned with wartimedevelopments in the field. A feature is the application of operational calculus andthe Laplace transform methods to the study of acoustical transients.

GENERAL AND APPLIED CHEMISTRY. A Brief College Course

By ARNOLD J. CURRIER and ARTHUR RosE, The Pennsylvania State College. Inter-national Chemical Series. Ready in AprilIn this forthcoming text the authors present a brief treatment of the subject whichconstitutes a distinct departure from the current textbooks in general economics. De-signed primarily for students in agriculture, engineering, home economics, and otherapplied sciences, and the liberal arts, it provides in concise form the more commonlyrecognized material on the nonmetals and the metals.

RURAL HEALTH AND MEDICAL CAREBy FREDERICK D. MOTT, M.D., and MILTON I. ROEMER, M.D. Ready in April

An unusually comprehensive analysis of a subject that has been of growing concernto the nation for many years. In bringing together for the first time a wealth of ma-

terial on rural health problems, the book describes the economic and historical develop-ments from which arise present difficulties in rural medical services, and then discussesthese difficulties and offers recommendations for future action.

Send for copies on approval

McGRAW-HILL BOOK COMPANY, Inc.MeN YL

330 West 42nd Street .New York 18, N. Y. .

13

.11 0

New

Radicallydifferent !

"ZIRCONARC" PHOTOMICROGRAPHIC LAMPFor better black-and-white and

color photomicrographsCombines the concentrated light of the Western Unionarc light bulb (about 1 mm dia.) with our fluorite-coated, 7-element aplanatic optical system of highestcorrection, free from chromatic aberration . . . Devicefor double intensity exposures... Practically harmlessto living cultures . . . Built with the same precision asthe microscope itself. Over-all length of lamp. 10".Height, 6i". Base, 41 x 61'. Price, complete withstarting box and 40-watt bulb, $325. Order director from leading supply dealers.

Write for Bulletin ZL-321FISH-SCHURMAN CORPORATION

230 East 45th Street, New York 17, N. Y.

Fish-Sch14rma14

CAMBRIDGE pH METERSThe three portable models illustrated above incorporate new andimportant advantages. A.C. line operation eliminates batterynuisance. Laboratory and Research models use electron-ray tubefor precise null-point indication. Industrial model is direct-reading, continuous-indicating; ruggedly built for plant use.Accuracy: Research .02 pH, Laboratory .05 pH, Industrial .10 pH.Cambridge pH equipment also includes single- and multi-pointindicators and recorders. Send for bulletin 910-MR.

CAMBRIDGE INSTRUMENT COMPANY, INC.3748 GRAND CENTRAL TERMINAL, NEW YORK 17, N. Y.

Pioneer Manufacturers ofPRECISION NSTRU MEINTS

a _Dg*s__

Inorganic andOrganic Chemicals

Biological StainsSolutions

0

Chemical IndicatorsTest Papers

Write for copy of our catalog

The COLEMAN & BELL Co.Manufacturing Chemists: Norwood, 0, U.S.A.

.~~ ~~ ~~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Desiccated, defatted stablepowders, processed at 400Cand 750C without autolysis.Liver, 400 and 750Kidney, 400Duodenum, 400Stomach Lining, 400Spleen, 400Pancreas, Activated 400

(1:25 to 1:150 trypsin)Pancreas, Not Activated, 400Beef Plasma, 400Beef Blood, 400 and 750Cytochrome CThyroid, 750Horse Heart, 400

Write for Catalog

VIOBIN CORP., MONTICELLO, ILL.

5

9

'tI1tetoS4~

A r4 AAASPublications

Spring book issuesThe spring book issues of SCIENCE

(April 30) and THE SCIENTIFICMONTHLY (published late April) willbe filled with interesting and usefulmaterial about scientific and technicalbooks.

SCIENCE will present two historicalarticles. One will cover the significantscientific and technical books during theAAAS century, 1848-1948. The secondarticle will present the growth and de-velopment of scientific journals duringthe same period. A third feature willbe an informational listing of overseaspublishers of scientific books.

THE SCIENTIFIC MONTHLY bookissue will feature the organization andmanagement of scientific information.Articles are being prepared by leadingscientists and staff members of librariesspecializing in scientific publications.Two contributions are planned from theLibrary of Congress's staff.

Both journals will have greatly en-

larged book review sections coveringrecently issued books from domestic andoverseas publishers.

Be sure to see both book issues. Therewill be no duplication of articles orbooks reviewed.

SCIENCE-April 30-25¢ the copy

THE SCIENTIFIC MONTHLY-May(published late April)-75¢ the copy

Order your copies today

15

PUBLISHERSof important scientific titles, bothreprints and originals, in mathemat-ics, physics, chemistry, and natural

science

PRI NTERSof monographs, dissertations, reports,and out-of-print books and journals

Write for information

EDWARDS BROTHERS, INC.Dept. S-15 Ann Arbor, Michigan

PHOTOVOLTLine-operated Electronic

pH MIETER

A Truly Universal Instrument. for laboratory and industrial application* for all types and designs of electrodesfor pH, titration, and oxidation-reduction potentialsfor all AC power lines 90-275 volts 50-0 cyclesavailable with or without portable wooden housingfurnished with shielded glass electrode, available

also with shielded compartment for unshieldedelectrodesPHOTOVOLT CORP.

95 Madison Ave. New York lb, N. Y.Also: Colorimeters Eleotronie Photometers

Fluorescene Meters Densitometers

Send orders to:Publications Office

1515 Massachusetts Avenue, N.W.Washington 5, D. C.

m- a

5 9

I I

Personnel PlacementCHARGES FOR CLASSIFIED ADVERTISINGRegular setting 10¢ a word. Minimum charge $2.50 foreach insertion. A box number counts as 8 words of theadvertisement (e.g. 25 words plus box number equals 33words). Make checks payable to the AAAS. All inser-tions must be accompanied by correct remittance and sent10 days in advance of publication date to the AdvertisingDepartment, AAAS, 1515 Massachusetts Avenue, N. W.,Washington 5, D. C.

POSITIONS WANTED

The California Medical Bureau, Agency for scientific and lay per-sonnel in medicine, biology, chemistry, physics and allied sciences,supplies teachers, research workers, laboratory dieners, skilled officehelp. Prompt service. Registration free. Your patronage re-spectfully solicited. THE CALIFORNIA MEDICAL BUREAU,Agency, Arcade Medical Center, 696 Colorado Street, Pasadena 1,California.

Anatomist: Ph.D. 15 years experience in gross and microscopicanatomy. Broad background in training and research. Now en-gaged. Desires advanced position in teaching-research. Box238A, SCIENCE.Bacteriologist, Immunologist: Biochemistry background. Teach-ing and research, woman. M.A. equivalent. Considerable ex-perience and responsibilities, research and immunization, leadingeastern institution. Publications. Box 239A, SCIENCE.Biochemist: M.S. in June; age 23; college mathematics and chem-istry teaching experience; virus and antibiotics research experience;pharmacology publication; excellent references; protein and micro-biological chemistry specialty. Box 240A, SCIENCE.Geologist-Mineralogist: Ph.D., 32, wants teaching and researchposition in university. Familiar with X-rays, polished sections,differential thermal analysis, goniometers, and petrographic meth-ods. Now teaching. Desire new appointment with greater op-p)ortunity for development. Box 241A, SCIENCE.Organic chemist, Ph.D., M.I.T., 1940. Married, age 33. Ad-ministrative and research experience. Desires position as researchor development chemist. Available immediately. Box 242A,SCIENCE.Parasitologist: two years, entomologist in the West Indies; sevenyears on faculty of medical school, including three as head of de-partment of parasitology; for further information, please writeBurneice Larson, Director, Medical Bureau, Palmolive Building,Chicago 1 1.Pathologist: M.D., Diplomate in Pathology, thorough backgroundin internal medicine and pathologist to cancer research laboratoryfor many years. Desires position in oncology department or wheredepartment of oncology is being established. Numerous publica-tions. Box 236A, SCIENCE.Physicist: Ph.D. Assitant Professor large university; ten yearsvaried experience teaching, academic and industrial research, phys-ics, electronics, meteorology; seeks industrial or academic position.Box 237A, SCIENCE.

POSITIONS OPENPositions Open: (a) Professor and head of department of physiol-ogy, university medical school having important expansion pro-gram; should be interested in developing department. (b) Physi-cian willing to relinquish clinical medicine to become associatedwith pharmaceutical company; duties include approving from tech-nical standpoint all literature, both promotional and informative;preferably one capable of taking complete charge of all publica-tions; research or teaching experience desirable; East. (c) Bio-chemist; preferably one whose background and qualifications arein protein and cellular biochemistry; cancer department, universityhospital. (d) Pharmacologist to head department university medi-cal school; Ph.D. or M.D.; $6,000-$7,000. (e) Organic chemist;Ph.D., for cancer research project, department of surgery, univer-sity medical school; would work independently; Middle West. (f)Physician experienced in virus reesearch; research position guaran-teed for five years or more; university medical school; West. (g)Organic chemist; Ph.D. to do research in synthetic organic chem-istry division; large pharmaceutical company; East. S3-3 MedicalBureau (Burneice Larson, Director), Palmolive Building, Chi-.cago 11.

Universities and Colleges throughoutAMERICAN the United States continue theirreat demand for recommendationsCOLLEGE For those trained in the differentfields of Science. The positionsBUREAU range from instructorships to heads

of departments.23 E Jacksen Blvd.

Chicago 4, IL Our service is nation-wide.

,16

Personnel PlacementFELLOWSHIPS AND GRANTS AVAILABLE

POSITIONS OPEN

Assistants in Biology: A.B. degree; candidate for M.A.; halftimelaboratory teaching; $1,000 plus tuition. Also open, a researchassistantship in physiology on same terms. Apply to H. B.Goodrich, Department of Biology, Wesleyan University, Middle-town, Connecticut.

Bacteriologist: A well-established manufacturer of sanitary chemi-cals requires the services of a bacteriologist, preferably with ex-perience in public health sanitation, to screen and evaluate newchemicals as microbiological control agents, developing new pro-cedures as needed; to formulate sanitary chemical compositions;and to conduct performance studies in the field. Ph.D. preferred.Training in organic chemistry -and mycology helpful. Addressreply to: Director, Whitemarsh Research Laboratories, Pennsyl-vania Salt Manufacturing Co., Box 4388, Chestnut Hill P. 0.,

Philadelphia 18, Pa.

Bacteriologist: College graduate, some background in chemistry.Take charge of section in research project. Salary to $4,200.Box 178A, SCIENCE.

Biochemist-Pharmacologist: Young, recent Ph.D. desired forposition on pharmacology staff of eastern university medicalschool. Teaching and research. Reply immediately. Box 227A,SCIENCE.

Graduate Assistants wanted: Starting in September, load 12 or 6hours per week. Remainder of time available for graduate workleading to Master's degree. Stipend $1,000 or $550. ChemistryDepartment, Howard University, Washington, D. C.

Pharmacologist: To head pharmacological group of a well knownpharmaceutical and chemical company. Pleasing personality andleadership ability essential. Please state education and experience.Box 234A, SCIENCE.

Wanted: Physics teacher to head department September, 1948. ingrowing, fully accredited liberal arts college. Moderate living ex-penses in splendid college community. State qualifications. In-terview may be arranged at our expense. President, LincolnMemorial University, Harrogate, Tennessee.

Metallurgists: Research and development. Excellent opportunitiesfor young metallurgists, 30 years of age or under, B.S. in metal-lurgical engineering. Vacany exists in pure research on vacuummelted alloys. Others include positions in the studies of alloys foruse at extremely low and high temperatures. Babcock and WilcoxResearch and Development Department, Alliance, Ohio.

The Market PlacePROFESSIONAL SERVICES

Medical and Research Writing for Scientists, libraries, and phar-maceutical industry. Comprehensive excerpts, reviews, transla-tions, searching scientific literature (French, Italian, Spanish, Ger-man) by former university professor still connected with medicalcollege, medical and scientific societies and libraries. Box 235A,SCIENCE.

LANGUAGES

LINGUAPHONE MAKES LANGUAGES EASYAt home learn to speak Spanish, Portuguese, Italian, French,German, Russian, by quick easy Linguaphone ConversationalMethod. Save time, work, money. Linguaphone CorrespondenceCourses are available to Veterans under GI BILL OF RIGHTS.Send for free book. State if GI. LINGUAPHONE INSTI-TUTE, 84 RCA Bldg., New York 20, N. Y.

GRADUATE FELLOWSHIPSTHE UNIVERSITY OF TEXAS

Rosalie B. Hite Fellowships in Cancer ResearchPost-doctoral $3000, Pre-doctoral $1500

For information concerning these fellowships,fellowships in other fields, and teaching

fellowships, address:

Dean of the Graduate SchoolThe University of Texas

Austin, Texas

The Market PlaceBOOKS

WANTED TO PURCHASE SCIENTIFIC BOOKSAND PERIODICALS

Entire libraries, and smaller collections; sets and runs;foreign and domestic.

WALTER J. JOHNSON,125 East 23rd Street, New York 10.

Journals, Periodicals, Learned and scientific serials bought andsold. Complete or part sets, back volumes. J. S. CANNER &COMPANY, INC., 909 Boylston Street, Boston 15, Massachu-setts.

Send us your Lists ofSCIENTIFIC BOOKS AND PERIODICALS

which you have for sale.Complete libraries; sets and runs; and single titles are wanted.

Also please send us your want lists.STECHERT-HAFNER, INC., 31 East 10th Street, New York 3.

For Sale: PLANT PHYSIOLOGY, complete run 1926 through1946, bound, good condition. Excellent opportunity for indi-vidual or library to acquire this important series beginning withVolume 1. Price, $8.00 per volume. Write to Mrs. Earl Johnston,4409 Beechwood Road, Hyattsville, Maryland.

ISUPPLIES AND EQUIPMENT

All Amino Acids (natural and synthetic), rare sugars, biochemicalproducts and reagents, new pharmaceuticals in stock. Write forcomplete price list. BIOS LABORATORIES, 607 West 43rdStreet, New York 18.

Amino Acid and protein analysis by microbiologic methods. Re-search problems on contract basis. SHANKMAN LABORA-TORIES, 2023 South Santa Fe Ave., Los Angeles 21, California.

Laboratory Animals-Rabbits, Guinea Pigs, Mice, Rats, Pigeons,Hamsters, Cats, Dogs. Reasonably priced.-JOHN C. LANDIS HAGERSTOWN, MD.

The Market PlaceSUPPLIES AND EQUIPMENT

Pre-Mized Microbiological Assay Media (One complete mixture):assay standards: pure amino acids (analysed): microbiologicalassays. H. M. CHEMICAL COMPANY, LTD., 144 NorthHayworth Avenue, Los Angeles 36, California.

Wanted: Micro-Tessar lenses in good condition only. W. Olden,1265 Broadway, New York 1, New York.

|HOLTZMAN RAT CO. 111Specializing in the Production of High Quality White Rats

for Laboratory Use.

R. 4, MADISON 5, WISCONSIN PHONE GIFFORD 7188

17

BOOKS | LARGE STOCK OFSCIENTIFIC AND TECHNICALWORKS ALWAYS AVAILABLE

LONDON : H. K. LEWIS & CO., LTD.136 COWER STREET, W.C.;.

Cables: Publicavit : Westcent : London : England.

RESEARCH AND DEVELOPMENTPOSITIONS

Senior-Intermediate-Junior level for participa-tion in the program of investigating the applica-tion of nuclear energy to the propulsion of- aircraftnow being carried on at Oak Ridge, Tennessee.Salaries will be commensurate with qualifications.

Inquiries welcomed fromPHYSICISTS-CHEMISTS-CHEMICAL

ENGINEERSMETALLURGICAL and CERAMIC ENGINEERS

METALLURGISTSMATHEMATICIANS

AERONAUTICAL and MECHANICALENGINEERS

AIRCRAFT POWERPLANT DESIGNERSand ENGINEERS

In the fields of

Nuclear, Theoretical, Experimental and Applied Physics;Physical and Chemical Studies at High Temperatures;

Physical, Analytical and Inorganic Chemistry;Nuclear and Radiation Chemistry;

Refractory Metals Technology; Powder Metallurgy;Elevated Temperature Investigations in PhysicalMetallurgy, Ceramic Bodies or Ceramic Coatings;

The Mathematical Analysis of Physical Problems includingNuclear Physics, Heat Transfer, Mechanics and Statistics;Aerodynamics; Stress, Weight and Structure Analysis;

Thermodynamics, Heat Transfer and Fluid Flow;Design-Layout-Testing of Powerplant,

Installations and Test Equipment;Literature Research and Technical Report Preparation.

Send resume, including small photograph, to

Employment Office

NEPA DIVISIONFAIRCHILD ENGINE AND AIRPLANE CORPORATIONP. 0. Box 415, Oak Ridge, Tennessee

Index of Refraction Liquids for Immersion Meth-ods of Microscopy. Stable, non-volatile, certifiedliquids 1.400 to 1.700; high index liquids, above1.80, in preparation. Write for data S47-ND.

R. P. CARGILLE,118 Liberty St., New York 6, N. Y.

t

Light Metals inStructural Engineering By L. DUDLEY

Here is long-needed information for engineers who find difficulty in applying basicengineering principles to problems involving the use of light alloys, because of the lackof published data on the characteristics and possibilities of these materials, and forthose who have had no formal contact with the subjects known as strength of materialsand the theory of structures. This book is intended primarily to assist those engagedin these two spheres, and includes much information required for the examinations inthe strength of materials, set by the various professional engineering institutions.Cambridge University Press. $6.50

A Textbookof Heat By G. R. NOAKES

This book provides a logical course in Heat. Great care has been taken that principlesare properly grasped and that simple experiments can be carried out with limited ap-

paratus. The common pitfalls are pointed out and carefully explained, and the authoris precise on such matters as Newton's Law of Cooling, and Kirchhoff's Law. Also,stress has been laid on the importance of considering the accuracy of experimentalwork. To a large extent the book is an accumulation of ideas and methods that havebeen found good and assimilated during years of teaching. A list of problems followseach chapter. Cambridge University Press. $3.00

General Chemistry By HARRY N. HOLMES

One of the most popular first-year college texts, this book is noted for its wealth ofdescriptive material. All the material is presented in a way which is interesting to thestudent and at the same time shows him the practical importance of chemistry in mod-ern life. Industrial applications are given wherever possible, and many illustrationsare used. The basic principles and some of the interesting applications of organicchemistry are also included. Fourth Edition. $4.15

LABORATORY MANUAL is also available. Fourth Edition. $2.25

THE MACMILLAN COMPANY * 60 Fifth Avenue * New York 11

18

__THEb __

o I ~SCALERFEATURES OF THE NEW "64" SCALER

* DUOSCALE REPLACEABLE SCALING UNITS. The only commercial scalerusing the Duoscale, a plug-in scale of two unit for simplifying service and repairproblems.* SCALING CIRCUIT. A scale of sixty-four embodying an improved versionof the well known Higginbotham circuit.* REGISTER. Equipped with a built-in panel mounted Wizard mechanicalregister with zero reset provisions.* HIGH VOLTAGE POWER SUPPLY. Built-in high voltage supply is con-tinuously variable from 600 to 1800 volts, with a Weston H-V meter mountedon front panel.

Available from stock at a price of $395.00, less G-M tube,

F.O.B. Boston (export and Canadian price add 10%).

_, MKETALLURGICALMICROSCOPES

Nill ItI'OK that is simple to operate, that is sturd Cenourlgh totake har(I usage . . . that provides iiicreased lsrilliance and contrast-mnuims glare that is alwzay s cool enough to handle.

Pioneered by American Optical Company, the Spencer VerticalI hinminator has a first surface usirror, and coated plano-glass re-flector, conveniently initerclhang,,eable. Additional features are fieldand aperture diaphragms, built-in light iiiteussitN control, and inter-changealble filters.

SP}ENCER XIETALLU RGICAL I11CR0SCOPES offer muuany other oit-stain(ingi adxvainames:

* QUICK-CHANGE NOSEPIECE facilitates interchange of objectives* COATED OPTICS eliminate reflections and provide added contrast* WIDE RANGE STAGE adjusts to unusually large or small specimens* LARGE RESEARCH-TYPE STAND has interchangeable body tubes* FINE ADJUSTMENT is precise, enduring micrometer screw type* POLARIZING FILTER AND CAP ANALYZER (accessories; enable the

use of polarized light)* GROOVED BEARING SURFACES assure long wear* ELEVEN STANDARD COMBINA-TIONS offer choice of stages, optics, Ailluminators, and body tubes American y Opticc

CSM nPAYnScientific Instrument Division

Buffalo 15, Newf YorkFor further in formation write Dept. C3.

al