Jl-ii 8, 1945 SCIENCE-ADVERTISEMENTS 9

PRINCIPLES OF RADIOBy KEITH HENNEY, Editor, "Electronics"

The fifth edition of this textbook has been revised toinclude the latest developments in the field of radio.As in previous editions the book is written for the stu-dent with little background in radio, and the languageis clear and non-technical. Problems likely to be en-countered in actual practice. are given to show theapplication of the principles explained.

Beginning with the fundamental principles of electric-ity, this book develops gradually the subject of radiopractice. The values of currents, voltages, etc. are

fully treated. Numerous specific examples, experi-ments and problems are given in this edition, and thebook is well illustrated and supplemented with draw-ings, diagrams, and photographs of actual apparatus.The experiments discussed have all been worked out inthe laboratory; they are not theoretical.

NEW in this edition:New material on wave guides,velocity modulation tubes, fre-quency modulation, Klystrons;

On ultra high frequency tech-niques, and apparatus; newchapters on measuring instru-ments, magnetic circuits;On Kirchhoff's laws-on powerfactor, filter circuits, differenti-ating and integrating circuits;

On pulses, transients, squarewaves, voltaae and current reau-,---a_--.--- . -U.,. v

lator tubes;On filter design for power sup-ply, tuning indicators, horn radi-ators, magnetrons, vacuum tubevoltmeters, cathode ray oscillo-graphs.

For sixteen years "Henney" has furnished the stu-dent in radio work exactly the background he needs;this fifth edition contains the complete, up-to-the-minute information necessary for a thorough under-standing of radio.

Fifth editionMay 1945534 pages55/8 by 77/8

$3.50

JOHN WILEY & SONS, Inc., 440-4th Ave., New York. 16, N. Y.1 -0am..

Juxz 8., 1945 SCIENCE-ADVERTISEMENTS 9

SCIENCE-SUPPLEMENT VOL. 101, No. 2632

SCIENCE NEWSScience Service, Washington, D. C.

THE ALLOCATION OF FREQUENCIES IN

THE RADIO SPECTRUMAFTER several months of deliberation the Federal Com-

munications Commission has finally made up its mind how

it will allocate space in the radio spectrum to standard

broadcasting, television, airplane radio, police and other

services. The stumbling-block in making final the FCC

proposals published last January were the long-drawnout

objections registered by owners and operators of Fre-

queney Modulation (FM) radio stations. FM radio is

staticless broadcastingNo final decision has yet been reached by the FCC

regarding the place in the radio spectrum that will finally

be set aside for FM or for the space below 25 megacycles.Three possible sections of the waveband are under con-

sideration, and during the coming summer months, scien-tists of the FCC will experiment with FM broadcasting in

these three parts of the spectrum to determine which ofthe three is best for FM radio. These experiments will

be conducted at the field offices of the FCC, from whichFM broadcasts will originate. Cellulose tape recordingequipment that can record sound for several hours with-out stopping will be placed at various spots in the area

around each FM station. Continuous recordings will bemade day and night. From these recordings, engineerswill be able to find out just which section of the spectrum

permits FM broadcasting with the least interference.The spectrum is still congested, although every service

that asked for space in the airlanes got at least a partof what it asked for. In making the decisions, the com-

missioners engaged in a give-and-take study, giving more

space to services which proved by their testimony thatthey needed more frequencies in order to carry out theiroperations in the public interest, and to new services thatpromise to extend the use of radio to the benefit of more

people.Probably the most important new radio service is the

Citizens Radiocommunication Service, which will make it

possible for every U. S. citizen to have his own broad-

casting station in the form of walkie-talkie or handie-talkie equipment. Regulations covering licensing andoperation of the equipment will be simple and easy tocomply with. The only stipulation made by the FCC is

that no charge may be made for messages carried over

the air in this portion of the spectrum.Other new services that have heretofore never been

licensed are radio for railroads; rural radio communica-

tion for farmers that will permit them to reach telephonecommunication lines and make use of telephone service

even though they have no telephones; and mobile radio for

buses and cross-country trucks.The allocations extend to 30,000,000 kilocycles in the

spectrum, farther than the FCC has ever before licensed.

This is by no means the upper limit of the radio spectrum,and in the future the FCC may allocate channels to ser-

vices beyond that super-high frequency range.-ZROBERT N.

FARR.

ITEMSWATER for drinking purposes is sterilized, to destroy

microorganisms and free it of all biological contamina-

tions, by a treatment, just patented, in which it first is

subjected to positive pressure and moderate heat, and thenrinjected into a high vacuum. The patent was granted to

James A. Camelford, of Cleveland, who has assigned it to

the Buckeye Laboratories Corporation. In the process, the

contaminated water is strained or filtered to remove solidimpurities, and then passed through a high-pressure pumpwhich puts a pressure of from 1,000 to 4,000 pounds per

square inch on it. It is heated to about 125 degrees Fahr-enheit, then sprayed through a nozzle into a vessel main-tained at as nearly a perfect vacuum as possible. Theresult is a palatable water relatively free of biologicalcontaminations.

DIATOMACEOUS earth will be used to filter water in allnew purification units shipped to the armed forces in thePacific as a result of tests conducted by the EngineerBoard, Fort Belvoir, Va. The new filter, experimentsshowed, not only removes the cysts of amoebic dysenterybut also filters out the blood flukes prevalent in Philippinewaters. Another improvement featured by the new puri-fication units is the glass-fiber tank which, coated withBuna S rubber, replaces the old canvas type. It will notmildew and is little affected by climatic changes. Whereasthe canvas tank loses a considerable quantity of water

before the fibers swell to waterproof proportions, the new

type is waterproof and fills at once. It is presumed that

U. S. troops going directly to the Pacific field from Europewill take their old-style purification units with them.

Plans are being made to equip them with the newer type.

RADAR, the radio echo device that can pick up targetsthrough the clouds and spot airplanes miles away, mayconfuse homing pigeons and cause mild headaches amongmen who operate the device. Studies of the effects of

microwaves and ultra-high frequency short waves uponpigeons and men are being made by Major Otto Meyerand Lieutenant Commander L. E. Daily, a Navy doctor.

While no evidence of physical damage has been dis-

covered among the men who operate the Navy's radar

devices, some of the men reported mild headaches and

the feeling that their faces were flushed. These symptomsare reported to have ceased when they were more than

four feet from the radio wave emissions of the transmit-

ting equipment or the receiving antennae. These studies

have disproved the theory that radar waves might cause

baldness, and that radar emissions interfere with the

ability of men to father children. Periodic physical ex-

aminations of radar operators are being continued, as is

the practice of shielding the men from the radar waves.

The long waves of ordinary radio do not seem to bother

pigeons, but they appear to be somewhat upset by the

short radar waves. The Signal Corps is investigating the

matter because officials hope the study may show whypigeons can find their way home.

10

SCIENCE-ADVERTISEMENTS 11

PrincetonBooks

on theScience of

Mathematics

The Psychology ofInvention in the

Mathematical FieldBy JACQUES HADAMARD

An engaging, informal analysis of the workings of a mathemati-cian's mind, based partly on the author's introspection and partlyon the writings and statements of many other noted mathemati-cians.

Among the phenomena discussed: Conscious and unconsciousthinking, the use of mental images and symbols, "logic," "in-tuition." $2.00

How to Solve ItA New Aspect of Mathematical Method

By GEORGE POLYA

A disarmingly elementary book which tells in general terms, andand with a wealth of illustrations, "what everybody knows butnobody cares to express; the procedures of the mind in searchingfor solutions of problems." The examples are simple, but themethod is applicable to a whole range of problems in many scien-tific fields. May. $2.50

At your bookstorePRINCETONUNIVERSITY

PRESS,Princetonz, N. J.

The Meaning ofRelativityBy ALBERT EINSTEIN

A reissue of the classic presentation of the theory of relativity,with an appendix discussing advances in the theory since 1921.

$2.00

JUNEa 8, 1945

12 SCIENCE-ADVERTISEMENTS Vol.. 101, No. 2632

Rgers The MOsquitoesofNw Jersey

University AND THEIR CONTROL

By THOMAS J. HEADLEEProfessor Emeritus of Entomology, Rutgers University

An authoritative, practical, and useful guide to mosquito biology and

ssS control, the permanent record of a lifetime of work on the subject.An invaluable tool for all entomologists, mosquito control workers,sanitary engineers, and public health officials.Illustrated with 87 line cuts and 16 pages of half tones, includingdrawings of practically every adult and larva of 37 species.

Over 300 pages, $4.00

Inselination ofOUTSTANDING

TECHNICAL Farm AnimalsPUBLICATIONS By ENOS J. PERRY and others

A new technique is revolutionizing livestock breeding throughout theworld. Here is the first complete book on the subject in the Englishlanguage, a thorough analysis by 7 internationally recognizedauthorities. 47 illustrations, $3.50

Molecular Films, the Cyclotron,

and the New BiologyBy HUGH STOTT TAYLOR, ERNEST 0. LAWRENCE, and IRVING LANGMUIR

With Commentaries by Leslie A. Chambers and J. R. Dunning

BIOLOGICAL ABSTRACTS: "These three essays taken MOLECULAR FILMS IN CHEMISTRY AND BIOLOGY: Newtogether show how modern science is once again methods for hitherto insoluble problems.interacting within itself to realize its full possi- by Irving Langmuirbilities.", Contents: NUCLEAR PHYSICS AND BIOLOGY: The cyclotron-

FUNDAMENTAL SCIENCE FROM PHLOGISTON TO CYCLO- atom-smasher and transmuter-and the problems itTRON: The interdependence of physics, chemistry, will solve. by Ernest 0. Lawrenceand biology. by Hugh Stott Taylor Illustrated, $1.25

At all bookstores, or RUTGERS UNIVERSITY PRESS, New Brunswick, N.J.

hi m ri- a IMMI1M-""qt~~~~ IMU.

12 SCIENCE-ADVERTISEMENTS VOL. 101p No. 2632

WOLL,1"L&"-"L&

JUE8 95SIEG-DETSMNS1

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TEMPERATUREIts Measurement and Control in Science and IndustrySponsored by American Institute of Physicsand Fourteen Other Scientific Associations

"'Indispensable for any technical or scientific libraryworthy of the name."-ScienceThis collection of 126 papers by eminent chemists, engineers, metallurgists,physicists, physicians, and biologists presents exhaustive descriptions of all phasesof temperature technique. The scope is all-inclusive, ranging from the deter-mination of temperature scales to industrial pyrometry; from ice-point valuesto the theory of automatic temperature control. Here is an essential referencework for laboratories and libraries, as well as for all who are engaged in any phaseof temperature work.1,375 Pages $11.00

The CHEMICAL ACTION of ULTRAVIOLET RAYSBy Carleton Ellis and Alfred A. Wells

Second Editionby Francis F. Heyroth, University of Cincinnati

Comprehensive and authoritative. Part I deals with The Sources of UltravioletRadiation. Part II. Photochemical Processes. Part III. The Applicationsof Photochemistry to Industrial Products. Part IV. Applications of Ultra-violet Rays in Biology. Every new development and discovery, reactions, proc-esses, every aspect of this far-reaching subject has been thoroughly explored. Amost valuable work for study or reference. Essential for chemists, physicists,biologists, physicians, technologists in the Food, Paint, Glass, Rubber, Textile,Paper, Dye and Leather Industries. Indexed by subject and author.961 Pages Illustrated $12.00

Send for FREE 1945 Book Catalog-"Let's Look It Up"-(200 Titles)

REINHOLD PUBLISHING CORP.330 West 42nd Street New York 18, N. Y.Also publishers of Chemical Engineering Catalog, Metal Industries Catalog, Metals and Alloys, and Pencil Points

SCIENCE-ADVERTISEMENTS 13JUNE, 8; 1945

14 SCIENCE-ADVERTISEMENTS VOL. 101, No. 263.

' I HOW TO SOLVE PROBLEMS5 IN GENERAL CHEMISTRYBy Joseph A. Babor and Chester B. Kremer.

99 pages. $.75.fl HOW TO SOLVE PROBLEMS

IN QUALITATIVE ANALYSISBy Joseph A. Babor and

J. Kenneth W. Macalpine. 93 pages. $75.HOW TO SOLVE PROBLEMSIN QUANTITATIVE ANALYSIS

By Saul B. Arenson. 89 pages. $.75.IV HOW TO SOLVE PROBLEMS

IN PHYSICAL CHEMISTRYBy Joseph A. Babor and Garrett W. Thiessen.

215 pages. $1.25.

Number 01State

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There has been no price increase in any CROWELLtext or manual since before Pearl Harbor.

THOMAS Y. CROWELL COMPANY432 Fourth Ave. New York 16, N. Y.

IkG 1I9II aV11

INTRODUCTORY ASTRONOMYJ. B. Sidgwick

Foreword by Dr. Clyde Fisher"Of service to anyone who enjoys probing the mysteryof the stellar universe. Includes 50 maps and glossaryof terms."-Science and Mechanics $2.50

FROM COPERNICUS to EINSTEIHans Reichenbach

"A captivating volume concerning space, time andmotion-the essentials of astronomy. Explains rela-tivity by simple experiments."-The New York Times $2.50

PHYSICS of the 20TH CENTURYPascual Jordan

"In this brilliant work one of the leading contempo-rary physicists gives us his impression of the state ofmodern physics."-Chicago Sun $4.00

DICTIONARY of BIOCHEMISTRYProf. Win. Marlas Mallsoff

"A new and interesting venture. Much care andthought have been expended on its compilation."-Nature $7J0

Dictionary ofSCIENCE and TECHNOLOGY

In English, French, German, SpanishMaxim Newmark, Editor

"Separate indexes permit two-way references to allfour languages. An eminently thorough, timely, prac-ticable and useful book."-Prof. Harold Lenz, Queens College .00

Illustrated TECHNICAL DICTIONARYMaxim Newmark, Editor

"Based on the visual aid principle; an excellent ref-erence work."-Science and Mechanics"Useful, up-to-date, defines about 5,000 terms."-Library Journal $5.00

Encyclopedia ofSUBSTITUTES and SYNTHETICS

Morris D. Schoengold, Editor"Anyone faced with the selection and use of materialsshould welcome this handy reference volume. Theauthor has done particularly well."-General Electric Review $10.00

Principles of POWDER METALLT.URGYFranz Skaupy

A practical handbook written by one of the mosteminent men in the field. "Subjects include the pro-duction of metal powders and ceramic-metal parts."-Aero Engineering Review $3.00

At your bookstore, or order direct.

I PHILOSOPHICAL LIBRARY Publishers15 E. 40th St., Dept. Z, N. Y. 16, N. Y.

Please send me ..copies of the follow-I lug books (write in margin).

Enclosed are $.....NAME . ....... . .... .

ADDRESS-_ - _ _ _ __- __- __- __- __- __-

W, W.-

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14 SCIENCE-ADVERTISEMENTS vot. 101. No. 2632

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SCIENCE-ADVERTISEMENTS 15

P /2v WREMOTE CONTROL

ttwhier o*,19)CV@tR OR tA 4of variable sequence operations becomes an "everyday" procedure

with W&T Torsional Relays.Of particular interest to the engineer are a few design characteristics: RANGE -10 to 20 cycles per second. SENSITIVITY - Less than 3.0 seconds from impressionof a 5 volt 0.0012 ampere current pulse of constant amplitude and at the resonantfrequency to which the relay is adjusted. SELECTIVITY - Resonant frequency plusor minus 2.5% under above conditions for response. STABILITY - Excellent overa wide range of ambient temperature and pressure. CONTACT CAPACITY -Incontrolled circuit, 50 milliamperes.

Write for Technical Publication 252

t-WALLACE &TIERNANPRODUCTS, INC.

BELLEVILLE 9 NEW JERSEYA438

JUNE 8, 1945

16 SCIENCE-ADVERTISEMENTS 2632

LaMOTTECHLORINE COMPARATOR

This comparator provides complete facilities forcontrolling the chlorination of pool water. Eachunit is complete with calibrated comparison tubes,measuring pipette, reagent and color standards.Price $12.50 including instructions.

LaMotte Chemical Products Co.Dept. "H" Towson 4, Baltimore, Md.

Scientific Optical Instrumentsin Stock for

PROMPT DELIVERY

#10025 Spencer SpectrometerThis instrument is particularly adapted for use inteaching optics and with its accessories has a hostof useful applications. Write for leaflet. We alsohave microscopes and accessories in addition to pro-jection equipment in stock for prompt delivery.

JARRELL-ASH COMPANYManufacturers-Importers-Dealers

165 Wewbury Street Boston 16, Mass.

LaMOTTE COMBINATIONSWIMMING POOL TEST-

ING OUTFITThis outfit offers you aneasy way to make yourpool the safe, popularplace to swim. It is idealfor the control of residualchlorine and alkalinity in

pool waters within the

ranges specified by PublicHealth Authorities- thetests are simple and, canbe made quickly and ac-curately. The unit is

compact and portable. Price, complete with in-structions, $12.50 f.o.b. Baltimore, Md.

Microscopists!New leaflet gives interesting data on Im-mersion Oil for microscope objectives andoutlines eight advantages of Shillaber's Im-mersion Oil over Cedar Oil; also available:New Data on Certified Index of RefractionLiquids and Shillaber 's Examination Liquidsfor Microscopy.

Just ask for Leaflets 45-S

Reagento for Chemical Microscopy

Shillaber's Photomicrography, published 1944,by John Wiley & Sons, Inc., presents over 700pages of useful optical and microscopical datafor advanced workers in microscopy and photo-micrography. Will be furnished at publishersprice, $10.00; or, leaflet on request.

R. P. CARGILLE118 Liberty Street * New York 6, W. Y.

ESSENTIAL OILSAROMATIC CHEMICALS

PERFUME BASESBALSAMS, OLEORESINS

S. B. PENICK & COMPANY50 Church Street New York 7, N. Y.

16 SCIENCE-AD RTISEMENTS VOL. 101, No. 2632

IN T HE M A R ET PLACERae to be paid in advance: 10 cents a word, minimum $2.00; no discounts or agency commissions. Count eight words if a

box address is to be used. Copy should be snt to the Advertising Department, American Association for the Advancement ofScience, Smithsonian Institution Building, Washington 25, D. C.

POSTIONS OPENResearch Biochemist, having background in or-ganic and physical chemistry, needed for researchin enzyme studies. Recent Ph.D. preferred. In-teresting work. Good salary. Excellent oppor-tunity. In New York City. Please detail yourqualifications, availability and include recent snap-sot with reply. Box 142, " ScINCe," SmithsonianInstitution Building, Washington 25, D. C.Excellent opening with company located in NewYork City. Research man to develop new tech-niques-for the Electron Microscope. An individualwith imagination can make a name for himself ina new field. A Ph.D. in Physics, Physical Chem-istry or Biophysics, or equivalent by experience,with a background which will enable him to antici-pate important future applications of this new re-search tool. Box 162 " SCIENCE," SmithsonianInstitution Building, Washington 25, D. C.Medical Bacteriologist: Immediate opening largemetropolitan medical college fully accredited.State experience, qualifications, and salary. Box165, "ScIENCE, " Smithsonian Institution Building,Washington 25, D. C.Wanted-Chemist with organic interests for fun-damental and applied research on the structureof natural and synthetic fibers and their relation-ships to manufacturing processes and end-useproblems of a major textile product. Manufac-turer in vicinity of New York City. Positionsof permanent nature leading to group leadership.If interested request application form from A. G.ASHCROFT, Director of Research, ADix. SMITH &SONS CARPET CO., Yonkers, N. Y.Opportunities available. (a) Bacteriologist quali-fied to conduct fundamental and applied researchwork on bacterial transformation of petroleum hy-drocarbons: should be well grounded in soil bac-teriology or industrial microbiology, biochemistryand quantitative analysis and able to direct re-search; research laboratories, petroleum company;Pacific Coast; $4000-$6000. (b) Anatomist,thoroughly conversant with gross and appliedanatomy for posts of assistant or associate pro-fessor; about $4000, month 's vacation; reappoint-ment yearly; East. (c) Electrophysiologist and,also, general physiologist; research appointment;$3500-$6000; Middle West. (d) Research assis-tant; department of physiology, university medicalschool; duties consist of collaborating in researchproblem concerned with physiology of vascular sys-tem; will be co-author of reports based upon work;college chemistry, physics, biology and medicalphysiology desirable qualifications. S6-1 MedicalBureau (BURNEICE LARSON, Director) PalmoliveBuilding, Chicago 11.

INSTRUMNTS FOR SALE

POSITIONS WANTEDOrganic Chemist, Ph.D., 1940. Three years collegeteaching; two years post-doctorate research. De-sires university teaching with research opportuni-ties. Woman. Box 163, "SCIENcE," SmithsonianInstitution Building, Washington 25, D. C.Biologist, Zoologist. Undergraduate and threeyears of graduate work all at leading universities.Nineteen years of College teaching, mostly Zool-ogy, Heredity, and Physiology in western stateuniversity. Publications. Stress personal rela-tionship to students. Protestant. Prefer to locatein South. Box 164, "ScIENCE, " Smithsonian In-stitution Building, Washington 25, D. C.Teaching Biologist, M.S., MA., completed coursestowards Ph.D., formerly (14 years), assistant pro-fessor of biology; now, head and professor of biol-ogy, desires change in position. Sixteen years ex-perience successful teaching premedical, predentaland nursing students biology, comparative anatomy,histology, biological technic and genetics. Box166, " SCIENCE,"' Smithsonian Institution Build-ing, Washington 25, D. C.

PERIODICALSWanted to purchase Scientific Periodicals, For-eign-Domestic. WALTER J. JOIDWON, 125East 23rd Street, New York 10, New York.For Sale: Medical, Chemical, and Boisetiflo Peri-odicals. Bets, volumes, copies. B. LOGIN ANDSON, INC. Established 1887, 29 East 21st St.New York 10.

SUPP&IES AND EQUIPMENTBALANCES REPAIRED

All work guaranteed; parts avail-able; balances insured while in ourfactory. Send for price list. Freeuse. of special shipping crates withcomplete packing materials, etc.Laboratory Equipment

Repaired d RefinishedBECKER BALANCES, INC.

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Write for New Cat. No. 67 onAnalytical Filter Papers

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M A C R 0 S C 0 P E SMEDICAL-INDUSTRIAL-AMATEUIRSupplies Accessories-Scientific Instruments

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For Sale: Spencer binocular compound microscope,single objective, erect image. Unused, as new. G.Crampton, Amherst, Mass.

M..9

THE OPTICAL TOOLS OF SCIENCE...THE RESEARCH MICROSCOPE

In physiological, medical and bacteriological researchthe Bausch & Lomb Research Microscope, Model DDE,represents the finest instrument of its type available.Superior mechanical construction resulting in betterbalance, stability and rigidity, combined with precisionB&L optics, qualify it for the most exacting researchwork in these vital fields. Preference rating desirablefor prompt delivery. Bausch & Lomb Optical Co.,Rochester 2, N. Y.

BAUSCH & LOMBE STABLI SHED 18 53

18 SCIENCE-ADVERTISEMENTS VOL. 101, NO. 2632

N CIENCE-ADVERTISEMENTS 19

a .nicroslide filing cabinet offerinv~ 5- greater

capa~cityatazngly low costo

This new "LAB-AID" cabinet is the ultimate solu-tion to the filing problems encountered in thelaboratory. It is of welded-steel, fire-resistant con-

struction throughout. Files 3'x1" or 3"x2" micro-

slides, 2"x2" transparencies, large lantern slides,index cards, even paraffin blocks ... in single-rowdrawers, all fining interchangeably into a smooth-tracking master drawer-rail system. Unit-sections,assembled in any combination, can be used singly,or stacked to any convenient height. With all theseadvantages, the cost-per-slide capacity in the"LAB-AID" cabinet is the lowest ever. Investigatethis remarkable equipment ... the coupon willbring details.

the new steel

labortory filing cabinetA single "LAB-AID" unit-section. Anycombination of drawers can be supplied.

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Excellent training of medical staff and fine modern equipment have madepossible the splerndid record of recovery from accidents and illness.

Aid for the InjuredThe world's finest laboratory equip-

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used for the most critical serial section-ing. It is graduated to cut tissue as thinas one micron or thicker sections inunits of one micron.

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20 SCIENCE-..ADVERTISEMENTS Vo 1- 1 0 1 . N. o. 216 321'