Kodak reports to laboratories on:an improved paper for photorecording ... circular neutral density wedges . . . taking thehemin out of hemoglobin ... high speed movies.

Photorecording"Once you've selected a KodakLinagraph Paper or Film best suitedto your requirements, you can treatevery roll of it alike without concernabout adjusting exposure and proc-essing practices." We make thatstatement in our literature and westand behind it, even though, ifyou've purchased Kodak Linagraph809 Paper recently, you may havenoticed that the same exposure re-sults in a blacker trace than before.We've improved the emulsion sothat it takes less exposure now toproduce the blackness you like, andwe've done it without increasing thedanger of fogging by stray light.It's still an abrasion-resistant, matte-surfaced, quick-fixing emulsioncoated on strong, pure white ledgerstock, still accepts pencil or inknotations smoothly and well.Kodak Linagraph Papers and Films aresold by the Kodak Industrial Dealer inyour area, and the number of combina-tions of types, sizes, and spooling speci-fications available for your photorecord-ing convenience runs into thousands.

Neutral density wedgesAmong the many items-photo-graphic, chemical, and optical-which Kodak supplies to small butearnest clienteles are neutral densitywedges composed of a carbon dis-persion in gelatin on glass. As amatter of fact, there is quite a vari-ety of them which we make asorders are received. They vary inprice from $15.60 for a plain wedgeof 10 by 1.5 cm size to $46.55 for a20 by 3 cm calibrated wedge withbalancing wedge; in density rangethey vary from 0-.3 (100% to 50%transmission) up to 0-4.0 (100% to0.01%). Lately we've had a flurry ofrequests for circular neutral densitywedges, particularly from experi-mental psychologists.We are happynow to report that these too areavailable in several sizes. Two ofthe more common ones are: 1)212'" diameter, 81/82" hole, 11/,io

wedge width, 0-3.2 density range,

$9.60; 2) 57/8" diameter, 3/4" or

¼/1.6" hole, -"' wedge width, 0-2.0or 0-4.0 density range, $30.Kodak Neutral Density Wedges are soldby your Kodak dealer, but we suggestyou let us prepare him for your visit byfirst explaining your requirements to In-dustrial Photographic Division, EastmanKodak Company, Rochester 4, N. Y.

C34H3204N4 FeCIHemin is part of the hemoglobinthat courses through the billions ofanimals that inhabit the planet. Get-ting it into the form we sell to re-searchers is a tedious process inwhich 3000 grams of crude hemo-globin bought from a meat packerwinds up as 20 grams on our shelves.Involved along the way are hot iso-amyl alcohol, hot acetic acid, deli-cate adjustment of a pyridine-chlo-roform system of solvents, coagula-tion of protein with hydrochloric

acid, slow crystallizations from vari-ous solvents without stirring, etc.,etc. From all this emerges the prod-uct, the chloride salt of an iron por-phyrin in which four substituted pyr-roles are joined by methylene link-ages around a central iron atom.Despite the conservative "97+%"-0

stated in our catalog and on ourlabel, our control lab reports semi-confidentially that the actual purityusually runs above 99%.This is but one of over 3500 organicchemicals appearing in Eastman OrganicChemicals List No. 38. If you haven'ta copy, write to Eastman Organic Chem-icals Department, Distilla-tion Products Industries, ElllRochester 3, N. Y.

High speedAs a tool for the engineering analy-sis of mechanical motions too fastfor the eye or even for the sportsnewsreel type of "slow motion," wemake the Kodak High Speed Cam-era. It can take from 1000 to 3200full 16mm frames per second andcan superimpose the correspondingoscillograph record on the picturesif required. It is simple to operate,and gives pictures of excellent pho-tographic quality. We have sold a

very respectable number of them topeople who have found its speedrange just right for the great major-ity of mechanical design problems.Nevertheless, there are problems,mostly in fundamental research,where simplicity, economy of oper-ation, and even image clarity mustbe sacrificed for higher repetitionrates. Several high speed camerasof such specialized design have ap-peared in recent years, and we arefrank in our admiration of them.The history of this branch of instru-mentation dates back at least to1880 and has its own terminology,literature, regular symposia, and acollection of impressive successes.A scholarly and exhaustive sum-mary of these lately appeared in oneof the engineering journals. Wehave had it reprinted and shall behappy to send you a free copy.

For the reprint ("Special Report onHigh Speed Photography in Design"),for inquiries about the Kodak HighSpeed Camera, or for help in selectingfilm or plates for anyform ofhigh speedphotography, address Industrial Photo-graphic Sales Division, Eastman KodakCompany, Rochester 4, N. Y.

This is one of a series of reports on the many productsand services with which the Eastman Kodak Company andits divisions are ... serving laboratories everywhere I i

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14

NUMERICAL SOLUTION OF DIFFERENTIAL EQUATIONSBy WILLIAM EDMUND MILNE, Oregon State College. This is the first thorough

coverage, in English, of this subject. It discusses the principal techniques available for thenumerical solution of ordinary and differential equations in as elementary a manner as itssubject matter permits. It avoids complicated mathematics, but does not gloss overdifficulties. Every important topic is illustrated with actual numerical examples, workedout in minute detail. They specifically show how to apply the processes discussed intheory to definite problems encountered in practice. A book in the 'WILEY APPLIEDMATHEMATICS SERIES, Edited by I. S. Sokolnikoff.

1953. Approx. 280 pages. Prob. $6.00.

ION EXCHANGERS IN ANALYTICAL CHEMISTRYBy OLOF SAMUELSON, Chalmers Institute of Technology, Goteborg, Sweden. Here

is the first book of its kind to be devoted to the analytical applications of the new syn-thetic organic ion exchangers. Dr. Samuelson has written a comprehensive study of theion exchange method from the viewpoint of a practicing analytical chemist. The threemain aspects covered are: 1) a discussion of the fundamental physical principles involved;2) a presentation of the techniques of both ion exchange separations and chromatography;and 3) practical applications of this new method, with numerous procedural details.Much of the information included has been almost unavailable before, having been pub-lished in periodicals with limited distribution.

1953. In Press.

CHEMICAL CONTROL OF INSECTSBy T. F. WEST, D.Sc., Ph.D. (Lond.), A.M.I. Chein. E, F.R.I.C., J. ELIOT

HARDY, D.Sc. (Prague), M.A. (Cantab.), F.R.E.S., and J. H. FORD, F.R.E.S. This isa comprehensive survey of the main insecticides emphasizing the more modern methodsand developments. It is a departure from the usual as the authors do not divide the subjectinto contact and stomach insecticides. Instead, they consider the destruction of insectsby toxic gases or vapors first and as an introduction. Then the more commonly knowninsecticides are dealt with. This provides a clearer picture of the impact on pest controlof the newer synthetic insecticides. Attention is also drawn to the gaps in knowledgewhich are inherent in the "newness" of these compounds.

1953. 277 pages. $3.25.

SYNTHETIC ORGANIC CHEMISTRYBy ROMEO B. WAGNER and HARRY D. ZOOK, both at The Pennsylvania

State College. Here, summarized in a single volume designed to save hours of researchtime, are the meth;ods most frequently used in the preparation of monofunctional anddifunctional organic compounds. This new book includes over 5 50 summaries of methodsemployed-organized according to functional groups, familiar and readily accessible toall chemists. It contains over 7000 references to the chemical literature, and over 6000organic compounds conveniently tabulated, along with references to well-written pro-cedures for their preparation, yields, and physical constants.

1953. Approx. 869 pages. Prob. $1i0.00.

Send for on-approval copies

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

February 6, 1953 15

SCIENCE, Vol. 117

PHOTOVOLT Densitometerfor

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FUNDAMENTALSOF COMPARATIVEEMBRYOLOGY OFTHE VERTEBRATES.~~~~~~~~~~~~~~~~

Dr. Alfred F. Huettner has prepared a manual coordinating laboratory work with therevised edition of THE FUNDAMENTALS OF COMPARATIVE EMBRYOLOGYOF THE VERTEBRATES, published in 1949. A Laboratory Manual of Com-parative Embryology gives a clear and concise outline of basic laboratory proceduresand includes numerous references to textbook illustrations, which coordinate practicallaboratory observations with textual information. Although the manual is designed pri-marily for use with Dr. Huettner's text, it can be used with other college embryologybooks.Ready in the spring

The text, THE FUNDAMENTALS OF-COMPARATIVE EMBRYOLOGY OFTHE VERTEBRATES, is planned chiefly to give pre-medical students training inthe morphological aspects -of various types of vertebrate embryos and to prepare themfor a thorough appreciation of human embryology. The author discusses in ascending orderthe emphioxus, the frog, the chick, and the pig. This revised edition includes two newchapters: History and Theories of Development and The Embryology of the Pig. Thedescriptive continuity, which won acclaim for the first edition, remains intact, althoughit is highlighted by the addition of certain phases of experimental embryology interestingto the elementary student. There are twenty-six new drawings of more than sixty indi-vidual illustrations.309 pages Price: $5.50

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What GENERAL ELECTRIC People Are Saying

J. J. FITZGERALD

Knolls Atomic Power Laboratory

SAFETY IN NUCLEAR OPERATIONS: Waste gasesas finally discharged into the air. from theKnolls Atomic Power Laboratory at Schenec-ta(lv, N. Y., are no more radioactive than thenormal surrounding atmosphere and in manyinstances are even less radioactive.

These gases are discharged throuigh a 100-foot stackt, and are constantly minitore(l tomake sure that the concentration of radlio-active material is kept well below permissiblelimits.

Constant air monitors are located at selectedsites to check the radioactive concentrations atvarious points near ground level. Plant samplesalso are analyzed on a regular scheldule toevaluate the accumuilation of radioactivity onvegeta tion.Waste radioactive gases and smokes from

the working areas are first passed throuigh a"scruibber." in which a caustic solution washesout the larger radioactive particles as well asthe more volatile components. Next thev gothrough a high-efficiencv filtering sYstem,which removes more than 99.9 per cent of thesmall amount of radioactive material left. Theair that remains is diluted, from a thouisand toten thousand times. with filtered air from theventilating system of the buiilding. an(l then isdischarged through the stack.As a result, in many instances the effluent

from our stack is cleaner than the atmosphereitself.

New York City

*W. R. G. BAKER

ElYectronics Division

ELEC1RONICS TOMORROW: Science cannot guardagainst the intellectual germ warfare beingcarried on by the proponents of the "something-for-nothing-isms." Engineers cannot designelectronic devices or atomic weapons to protectagainst this type of infiltration. But engineerscan make certain that their economic andpolitical education advances in step with theirtechnical education. The abilitv to separatetruth from propaganda is as important as the

ability to separate scientific fact from misinfor-mation. Your future mnav-depend on y-our abilityto do both.

Institute of Radio EngineersWashington, D. C.

*G. E. :hENRYGeneral Engineering Laboratory

CLEANING WlITH SOUND: It is now sometwenty-five years since Wood and Loomis firstdemonstrated the remarkable physical and(chemical effects of high frequencv. high power,sound in liquids. People have been busy, duringthis time. looking for ways to turn these effectsto practical advantage, especially in the chem-ical industry. During the last three or fouiryears, however, the most notable advanicesIlave been made not for the chemical producer.but for the metal-working industries-specifi-callv for those engaged in small-parts fabrica-tion. Ihigh power ultrasonics offers the bestmeans vet devised for cleanimigc these smiiallparts.An instrument ball bearing, a small pinup

fitting, or some other precision iniade workpiece is immerse(l in a solvent; a high-frequencysound wave beamed through the solvent strikesthe metal suirface and removes almost instantlyany film of oil or grease, together with dirt.chips, or other foreign matter.

There is no longer any quiestion of thesuperiority of uiltrasonic cleaning when thecharacteristics of the work piece and theeconomics of production are favorable for theapplication of the new method. The greatquestion remaining is how far the method canbe extended to include different kinds of parts-how large a proportion of the total metalcleaning business can be profitablv handiledwith ultrasonics.

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GENERAL * ELECTRIC

February 6, 1953 21

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POSITIONS WANTED 1|||||||||||||||||||||||Biochemist, M.A. (Zoology); minors: botany, chemistry, German,l,atin. Total: 9 years teaching experience covering biology, chem-istry, microbiology anatomy, physiology. Desires a teaching posi-tion, college level with research possibilities. East. September 1953.Box 17, SCIENCE. X

Bacteriologist: Ph.D. recent graduate, pharmaceutical researchexperience in bacteriology, parasitology, and protozoology. Seekindustrial research position. Box 25, SCIENCE. X

(a) Chemist; Ph.D. three years' teaching- seven years, seniorchemist and production superintendent industry; five, researchdirector, pharmaceutical company. (b) Virologist; M.S.; twoyears' teaching (Bacteriology) three years, virologist, large teach-ing hospital. Science Division, Medical Bureau (Burneice Larson,Director), Palmolive Building, Chicago. X

Physiologist, endocrinologist; Ph.D., 28; desires academic position.Teaching experience, publications. Initerested small animal research.Box 23, SCIENCE. X

Zoologist (Ph.D. January 1953) Botany minor. Desire academicanid/or research opportunity. Prefer western location. Experiencein geineral zoology, elementary physiology, histology, embryology.Principal research interests: physiology of avian reproduction andmigration; ecology. L. R. AMewaldt, Zoology, WSC, Pullman,Washington. X

Zoologist: M.S. 1 year experience cancer research using protozoaand rats; 1 year full time employment on Q fever research; taughtBiology course in college. 1 publication. Box 26, SCIENCE. 2/13

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Fellowship effective July 1, 1953 being offered by Dr. JessieMarmorston, M.D. for period of one year to work with group inRenal Physiology at Institute for Medical Research, Cedars ofLebanon Hospital, Los Angeles, California. X

(a) Associate Medical Director; pharmaceutical company; dutiesinclude clinical research, professional promotion; career post.(b) Bacteriologist trained in chemistry or along pharmaceuticallines; research on new products and control work; biologicalmanufacturing company, large city, Midwest. (c) Assistant Profes-sor or Instructor in Biochemistry; Ph.D.; midwestern medicalschool. (d) Clinical Psychologist; in addition to administeringpsychological tests, should be particularly well qualified psycho-therapy; neuropsychiatric department affiliated with group clinicand 200-bed hospital affiliated with university department of psy-chology; minimum $6000; West. (e) Physician or Ph.D.; researchon cholesterol metabolism; medical school research department,West. S2-1 Science Division, Medical Bureau (Burneice Larson,Director), Palmolive Building, Chicago. X

Medical and Research Director; M.D., not over 45 years withsolid background in pharmacology and chemistry. Should be cap-able of originating and supervising both synthetic chemical andbiological screening programs. A man who introduced a successfulnew drug and also had experience with cosmetics preferred. Re-sponsibility will include supervision of quality control of cosmetics,preparation and filing of F.D.A. applications, making arrangementsfor clinical trials of new drugs and cosmetics, and supervision ofpromotional activities. Salary open. Reply to Box 22, SCIENCE.

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In this room at the Donner Laboratory of the Uni- 3 Model E analytical units and 5 Model L prepara-versity of California can be seen perhaps the world's tive units routinely subject research samples ofgreatest concentration of usable, controllable cen- blood protein materials to 260,000 and 144,000trifugal force. Eight Spinco Ultracentrifuges: times gravity.

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You'll notice this typical AO Design Perfection also in therenowned Spencer Optics, dust-proof, dual-cone nosepiece,"pinch grip" mechanical stage, "autofocus", custom tension adjust-ment, built-in "full-field" illumination and many otherfeatures. But test the many AO Spencer advantages yourself.Ask your AO distributor for a demonstration or write Dept. P1.

I

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