dog & primate cagesMolded seamless construction ofrugged fiber glass reinforced plastics...minimum effort required to clean and

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write: - l.,Department KS

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DIFCO LABORATORIESDETROIT 1 MICHIGAN USALABORATORY PRODUCTS

BIOLOGICS CULTURE MEDIA REAGENTS

22 JULY 1966 465

ATTENTION MANUFACTURERS OF SCIENTIFIC INSTRUMENTS

You are invited, by the American Association for the Advancementof Science, to make application to be listed (free of charge) in the SCIENCE4th annual Science "Guide to Scientific Instruments."

ANttICA ASSOCIATION FOR T-z ADVAKCZMZNT or scit

APPLICATION FOR LISTINGSThis comprehensive directory of all types of scientific instruments, FOR 1966published on the fourth Tuesday of November, has been adopted bymost industrial, governmental, university, hospital, and institutionallaboratories as a standard reference. Approximately 140,000 copieswill be distributed to the scientific community.

Send requests for application forms (not later than 19 August, 1966)to:

Edward J. NerenAssociate EditorGuide To Scientific Instruments11 West 42nd StreetNew York, New York 10036

Positively no applications will be accepted after 5 September 1966.

22 JULY 1966 465

Checkthis list of

laboratory glasswareessentials availableto you at substantial

savings made byreliable MercerGlass Works Inc.

BEADS, GLASS

BOTTLES, ASPIRATOR

BOTTLES, BALSAM

BOTTLES, DROPPING

BOTTLES, EYE FLUSHING

BOTTLES, GLASSSTOPPERED

BOTTLES, NURSING

BOTTLES, PRESCRIPTION

BOTTLES, SADDLE BAG

BOTTLES, URINESPECIMEN

BOTTLES, VARNISH

BOTTLES, ZEISS

CHAMBERS,HEMACYTOMETER

CYLINDERS, GRADUATED

DESICCATORS

DISHES, CRYSTALLIZING

DISHES, DAPPEN

DISHES, EVAPORATING

DISHES, PETRI

DISHES, PREPARATION

DISHES, STAINING

DISHES, STENDER

DROPPERS, MEDICINE

FUNNELS466

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JARS, MUSEUM

JARS, SPECIMEN

JARS, STAINING

JARS, STERILIZING

JARS, STORAGE

JARS, THERMOMETER

JARS, URINOMETER

MORTARS AND PESTLES

PERCOLATORS

PIPETTES, DISPOSABLE,PASTEUR

SLIDES, CONCAVITY

SLIDES, MICROSCOPE

THERMOMETERS

TUBES, TEST

TUBES, CULTURE

URINALS

URINOMETERS

VIALS, APPLICATOR

VIALS, CAPSULE

VIALS, DROPPER

VIALS, PATENT LIP

VIALS, SCREW CAP

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Induced-air models; standardmodels; explosion-proof models;models for radioactive work.

For the complete, money-saving storycontact your laboratory supply dealeror write to Labconco Corporation,8811 Prospect, Kansas City, Mo. 64132

SCIENCE, VOL. 153

Kiett SummersonPhotoelectric Colorimeter

No. 800-3

Test Tube

Model

KLETT COLONY MARKER and TALLY

This instrument takesthe drudgery and er-ror out cf the count-ing of bacterial colo-iiies.

AiT/ett MANUFACTURING CO., INC.,179 East 87th Street, New York, 28, N.Y.

Appleton-Century-Crofts (Meredith), NewYork, 1966. 877 pp. Illus. $12. CenturyPsychology Series, edited by Richard M.Elliott, Gardner Lindzey, and KennethMacCorquodale. Nineteen papers.

Pattern Recognition: Theory, Experi-ment, Computer Simulations, and Dy-namic Models of Form Perception andDiscovery. Leonard Uhr, Ed. Wiley, NewYork, 1966. 405 pp. Illus. Paper, $5.95.Twenty-two papers on the followingtopics: Conceptual Framework: The Psy-chology and Philosophy of Perception andDiscovery (4 papers); Empirical Back-ground, Summaries, Reviews, and Integra-tions of Experimental Findings (4 papers);Theoretical Developments (4 papers); Ex-perimental Results from Neurophysiologyand Psychology that are Pertinent toModel Building (4 papers); and Com-puter Simulations of Complex Models (6papers).

Poverty Amid Affluence. A report ona research project carried out at the NewSchool for Social Research. Oscar Ornati.Twentieth Century Fund, New York, 1966.224 pp. Illus. Paper, $3.25.

Progress in Experimental PersonalityResearch. vol. 2. Brendan A. Maher, Ed.Academic Press, New York, 1965. 341pp. Illus. $9.50. Six papers: "Research inthe personal construct theory of GeorgeA. Kelly: Role construct repertory testand basic theory" by J. C. J. Bonarius;"Cognitive complexity and impressionformation" by Walter H. Crockett; "Aninterpersonal approach to personality" byPaul F. Secord and Carl W. Backman;"Personality and audience influence" byAllan Paivio; "The study of ordinal posi-tion: Antecedents and outcomes" by Ed-ward E. Sampson; and "Toward a theoryof classical conditioning: Cognitive, emo-tional, and motor components of the con-ditional reflex" by Roscoe A. Dykman.

Science and Economic Development:New Patterns of Living. Richard L.Meier. M.I.T. Press, Cambridge, Mass.,ed. 2, 1966. 295 pp. Illus. Paper, $2.45.

Social Change in Developing Areas. Areinterpretation of evolutionary theory.Herbert R. Barringer, George I. Blank-sten, and Raymond W. Mack, Eds.Schenkman, Cambridge, Mass., 1965. 334pp. Paper, $2.95; cloth, $7.95. Twelvepapers on the following topics: Theoriesof Social Evolution (3 papers); Studiesof Political and Social Change (5 papers);and Economic Development, Technologi-cal Change, and Evolutionary Theory (4papers).The Social System of Science. Norman

W. Storer. Holt, Rinehart, and Win-ston, New York, 1966. 192 pp. Illus. Pa-per, $3.95.The Structure of Associations in Lan-

guage and Thought. James Deese. JohnsHopkins Press, Baltimore, 1966. 232 pp.Illus. $6.50.

Technological Change: Its Conceptionand Measurement. Lester B. Lave. Pren-tice-Hall, Englewood Cliffs, N.J., 1966.250 pp. Illus. $6.95. Prentice-Hall Seriesin Mathematical Analysis of Social Be-havior, edited by James S. Coleman andJames March.A Textbook of Psychology. Donald Old-

ing Hebb. Saunders, Philadelphia, ed. 2,1966. 369 pp. Illus. $5.75.22 JULY 1966

The Tropical World: Its Social andEconomic Conditions and Its FutureStatus. Pierre Gourou. Translated fromthe French edition by S. H. Beaver andE. D. Laborde. Wiley, New York, ed. 4,1966. 208 pp. Illus. $5.

Ulithi: A Micronesian Design for Liv-ing. William A. Lessa. Holt, Rinehart,and Winston, New York, 1966. 130 pp.Paper, $1.75. Case Studies in CulturalAnthropology, edited by George Spindlerand Louise Spindler.

Unobtrusive Easures: Nonreactive Re-search in the Social Sciences. Eugene J.Webb, Donald T. Campbell, Richard D.Schwartz, and Lee Sechrest. Rand Mc-Nally, Chicago, 1966. 239 pp. Paper,$3.50. Rand McNally Sociology Series.Vyzkumme metody v sociologii: Teorie

a praxe sociologickych vyzkumu. FrantisekKahuda. Statni Pedagogicke Nakladatelst-vi, Prague, 1965. 389 pp. Illus. Paper,CK. 17.30.Word Associations of Young Children.

Doris R. Entwisle. Johns Hopkins Press,Baltimore, 1966. 611 pp. Illus. $12.50.

Miscellaneous Publications

The Annals of Applied Biology. Indexto volumes 1 to 50. Compiled by D. Aken-head. Cambridge Univ. Press, New York,1965. 240 pp. 40s. Indexes arranged byauthor and by subject.

Catalogue of Radioactive Products. TheRadiochemical Centre, Amersham, Eng-land, 1965. 203 pp.

Digital Logic Laboratory Workbook.Barbera W. Stephenson. Digital Equip-ment Corp., Maynard, Mass., 1965. 137pp. Illus. Paper, $5.

Evolution of Physical Control of theBrain. Jose M. R. Delgado. AmericanMuseum of Natural History, New York,1965. 58 pp. James Arthur Lecture onthe Evolution of the Human Brain.

Glossary of Terms Frequently Usedin Cosmology. Harold H. Rogers, Ed.American Inst. of Physics, New York,1966. 17 pp. Paper, $1.InterDok. vol. 1, No. 8, April 1966.

InterDok Corp., White Plains, N.Y.,1966. By subscription, $38 per year. Alist of currently available published pro-ceedings of conferences, meetings, sym-posia, and congresses. The following en-tries are typical: "June, 1964. Congresson Antibiotics: Biogenesis of AntibioticSubstances; Prague, Czechoslovakia. [Pub-lisher] Czechoslovakia Academy of Sci-ences, Prague, Czechoslovakia. $14."and "November, 1965. Nuclear Power,Seminar on; New York, N.Y. [Publisher]Atomic Industrial Forum, 850 Third Ave-nue, New York, N.Y. $7.50."The Krater and the Grail: Hermetic

Sources of the Parzival. Henry Kahaneand Renee Kahane. Univ. of Illinois Press,Urbana, 1965. 270 pp. Paper, $6.50. Illi-nois Studies in Language and Literature,No. 56.

Rainfall in Burma. Robert E. Huke.Geography Publications, Dartmouth Col-lege, Hanover, N.H., 1965. 93 pp.

Space Electronics. S. H. Fairweatherand J. E. Mortimer and others. RadioCorp. of America, Camden, N.J., 1965.72 pp. Sixteen papers.

467

I

i,.f

;i

INDEX TO ADVERTISERS

22 July 1966

Bausch & Lomb .... ......... 344, 345Beckman Instruments, Inc. 338

Bendix Corp., Cincinnati Div. ...... 463

Brinkmann Instruments .... ...... 463

Canal Industrial Corp ........ 461

Chemapec, Inc. 458

Chemical Rubber Co. ....... 368, 464

Chromatronix Inc. 366

Clay-Adams .349

Difco Laboratories ..... .......... 465Distillation Products Industries, Div.

of Eastman Kodak Co 348

E & M Instrunment Co., Inc 451

Esterline Angus Instrument Co., Inc. 339

Fisher Scientific Co 459

F&M Scientific, Div. of Hewleft-Ptckard. ..................... 360

Gilford Instrument Laboratories, Inc. 351Gilson Medical Electronics ....... 370

Hamilton Co. .................. 448Harvard Apparatus Co., Inc 454

Hewlett-Packard ............... 460Hyland Laboratories ............. 457

Institute for Scientific Information.. 468Instrumentation Specialties Co., Inc. 457International Chemical & Nuclear

Corp. ....................... 369International Equipment Co....... 365

International Light Inc 451

Kirschner Manufacturing Co 465

Klett Manufacturing Co., Inc 466

Kontes Glass Co .......... 471

Labconco Corp. 466

LKB Instruments, Inc ........ 354

Lourdes . .457

Matheson Co ............ 462

McDonnell . .348Mercer Glass Works ............ 466Mettler Instrument Corp ....... 451

Millipore Filter Corp ........ 462

Nagle Co., Inc 450

National Appliance Co 447

Norelco Division, Philips Electronicsand Pharmaceutical IndustriesCorp. ....................... 361

Nuclear-Chicago Corp 347

Owens-Illinois .359

Packard Instrument Co 372

Philbrick Researches, Inc 342

Phipps & Bird, Inc............... 455

Photovolt Corp 468

Polariod Corp. 363

Professional Tape Co., Inc 454

Sanborn Div., Hewlett-Packard 358Sigma Chemical Co 455

Sorvall, Ivan, Inc.. 346

Spectrolab, Div. of Textron Elec-tronics, Inc . 450

Thermolyne Corp. ............... 458Thomas, Arthur H., Co 472

TRG, a subsidiary of Control DataCorp 456

U.S. Stoneware ... 467

Warner-Chilcott Laboratories Instru-ments Div . 345, 357

Wild Heerbrugg Instruments, Inc. 449Williams & Wilkins Co 448

Wilmot Castle Co 367

Worthington Biochemical Corp. 469

A.

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SCIENCE, VOL. 153

-

468

'PaNnFnl -,QP.l F

I . PHD orDVM

with two or more years of experience in thegeneral area of Drug Toxicity evaluation inlaboratory animals. Recent graduates withtraining in this area will be considered also.The individual selected for this position willhave an excellent opportunity for professionaldevelopment within our expanding Toxicol-ogy-Pathology section. The responsibility ofthis position includes the design of Toxicitystudies and evaluation on in-life parametersof drug activity and toxicity. In addition toliberal company benefits these positions offersuburban living at its best in convenientNorth Jersey, just 30 miles from N.Y.C. servedby fine schools and close to all recreationaland educational facilities.

Please send resume & salary requirements to:R. J. WilliamsDirector of Professional Placement

PHARMACEUTICALS SANDOZRoute 10 Hanover, New Jersey

An Equal Opportunity Employer IJ,.

~IyyPPRSONNEL PLACEMENTI(a) Animal Science Ph.D. 1966; MVS; completinggenetic postdoctoral fellowship; seeks researchposition. (b) Nicrobiology M.S.; biochemistryminor; laboratory instrument design, sales ap-pointment. Write Woodward Medical PersonnelBureau, 185 North Wabash, Chicago 60601. X

Biologist-Phytopathologist (Ph.D.) seeks academicor research poitiosn. Experience with plant tis-sue cultures, single-cell injection, microsurgery,microgorging, cinemicrophotography. Box 157,SCIENCE.

Business Administrator, life-science research andcollege financial management, building, personnel,accounting. Box 158, SCIENCE. X

CYTOGENETICIST Ph.D. 6 years experi-ence in human cytogenetics. Has initiatedand supervised both genetic research andservice laboratories. Currently on medicalschool faculty. Publications. Seeks aca-demic/research appointment. Box 154,SCIENCE.

Medical Microbiologist M.D., Ph.D. 15 years'full professor of microbiology and director ofuniversity hospital bacteriological laboratory. De-sires suitable position preferable West Coast.Box 159, SCIENCE. X

Medical Translator (German/English) accepts free-lance assignments. Prompt service. Reasonablerates. Please write: 68-43 Groton Street, ForestHill, N.Y. 11375. X

22 JULY 1966

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

Neuroanatomist Ph.D., neurophysiology minor,postdoctoral and medical school teaching experi-ence, publications, grants, seeking academic orresearch position. Box 145, SCIENCE.

||||||||||||||| POSITIONS OPEN |||||||||||||||Expanding educational and research corporationoffers professional personnel career positions inits information, training, education, and medicalresearch programs. Activities are national andinternational in scope.

MathematicianBiophysicistPhysicist

Bacteriologist-Microbiologist

Wage & SalaryAnalyst

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PhD(Medical Research)(Academic/Research)(Academic/Research)BS-MS

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Officer (Technical)Medical Technologist (Research)Chemist (Academic/Research)Science Lecturers (Physical Science Degree)Analyst-Programmer (Fortran & Cobal Language)Bioengineer (Life Sciences Computer

Systems)Physicists (Academic/Research)Health Physicist (Academic/Research)

Personnel Office

OAK RIDGEASSOCIATED UNIVERSITIES

P. 0. Box 117Oak Ridge, Tennessee

An Equal Opportunity Employer

EMBRYOLOGIST - HISTOLOGISTAcademic position available September, 1966.Ph.D. preferred. Rank and salary dependenton degree attained and experience. Salarywill range from $6,000 to $10,000. Send ap-plications with vitae and names of refereesto Dr. Richard A. Ryan, Chairman, Depart-ment of Biology, Hobart and Wm. Smith Col-leges, Geneva, New York.

Research Associate, M.S. or equivalent in physiology,biophysics or zoology for ongoing research project onelastic properties of normal, denervated and dys-trophic skeletal muscle. Experienced in small animalsurgery and electronic instrumentation. Some teachingof undergraduates in research electives and supervi-sion of laboratory personnel if desired. $7,000 -$9,000. First inquiry should include resume andreferences.

Walter C. Stolov, M.D.Department of Physical Medicine and Rehabilitation

University of Washington HospitalSeattle, Washington 98105

INSECT MICROBIOLOGISTUniversity of California, Berkeley

Applications are invited from microbiologists for thestaff position of Insect Pathologist to study insectdiseases and their possible utilization in pest con-trol. Applicants w ith experience in bacteriology,mwycology, virology, or protozoology are preferred.Opportunities for teaching may be available. Rankand salary w ill be commensurate with qualifications.To submit applications, or for further information,u-rite: Division of Entomology, University of Cali-fornia, Berkeley, California 94720.

469

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............. ............. ......

....................... .................. ........

.......................... ............................... .................. ..........................

............................... -......................-

--i- I . - .. - - . .. -d A

POSITIONS WANTED POSITIONS WANTED 111111111111111111111illjllllll POSITIONS OPEN

-TRAININGFor Careers in

HEALTH

SCIENCE

ADMINISTRATION

Through the PHS GrantsAssociates Program

Scientists interested in the administrativechallenge implicit in Federal programssup-porting training, research, and services inhealth related fields are urged to consideropportunities in the Grants AssociatesProgram of the Public Health Service.The program provides a unique educa-

tional experience designed to prepare eachassociate for a career in health scienceadministration. For a 12 month period thegrants associate participates in an indi-vidually structured program. He has theopportunity of working with senior scien-tist administrators, attending seminars,visiting project sites, attending scientificmeetings and taking part in evaluation andanalysis of grant supported programs.

The nature of the biomedical and healthservices programs in the Public HealthService affords many opportunitiesfor exceptionally well qualified ScientistAdministrators.

If you hold a doctorate in a disciplinerelated to the biomedical sciences, includ-ing the behavioral sciences, have some

post doctoral research experience, and aremotivated toward the administration offederally supported programs in thebiomedical and behavioral sciences, you

should investigate the opportunities offeredby the Grants Associates Program. Thebeginning salaries for these Civil Serviceappointments range from $8,900to $14,500.For further information write: The Execu-tive Secretary, Grants Associates Program.

NATIONALINSTITUTESOF HEALTH

Westwood Building, Room 139ABethesda, Maryland 20014

An equal opportunity employer, MdF

470

ll||*||J|[ POSITIONS OPEN 111|g||||"RESPIRATORY PHYSIOLOGIST

HAZLETON LABORATORIES, a leading independentcompany specializing in the Life Sciences, needs a Ph.D.with 0-3 years' experience to conduct, design, coordinate,and evaluate animal research programs in the field ofrespiratory physiology and inhalation toxicology. Oppor-tunity for scientific meetings attendance and publications.Liberal employee beneflt program including proflt shar-ing. Salary commensurate with experience and education.Please send resume to: Hall A. Acuff, Asaistant Person-nel Manager, Hazleton Laboratories, Inc., P.O. Box 30,Falls Church, Virginia 22046.

An Equtal Opportunity Employer MIF

MICROBIOLOG ISTS

Ilazleton Laboratories, a leading independent companyspecializing in the Life Sciences, needs B.S. Micro-hiologists or Bacteriologists with 0-3 years' experience.Duties incltude microbial assay, biochemical, radiolog-ical, and immtunological research. Stable employment,chance for advancement, competitive salaries, excellenteducational assistance policy, and profit-sharing plan.Please send resunme or write for application. Hall A.Aeuff, Assistant Personnel Manager, Hazleton Labora-tories, Inc., P.O. Box 30, Falls Church, Virginia 22046.

An Equal Opportunity Employer M/F

UNIVERSITY OF GUELPHDEPARTMENT OF BOTANY

Applications are invited for (a) ECOLOGIST-special-izing in Ecosystems and Conservation; (b) GENETICIST-specializing in Fungal Genetics or Molecular Genetics.Teaching will include undergraduate and graduate infields of specialization and assisting in General Botanyor Biology. Appointisients will he as of January 1, 1967,and will he at the Assistant Professor level with asalary floor of $8,500, and adjusted to teaching experi-ence. Applications should be sent to Professor F. H.Alontgomiiery, Head, Department of Botany, IJniversity ofGuelph, Giielph, Ontario.

The Market PlaceSUPPLIES AND EQUIPMENT |

SPRAGUE.DAWLEY, INC.Pioneers in the development of theSTANDARD LABORATORY RAT.

P.O. Box 4220Madison, Wisconsin

CE 3-5318

Completely new, "hands-free" Magnifier has exclusive"flip-up" interchangeable lens plate that adjusts in-stantly to magnified or regular vision * Simply snap onextra lens plates for higher or lower magnification. Noscrews or bolts * Precision-oround optical olass lenses.Lightweight, adjustable, may be worn with eyeglasses.Available in Black or White. Only $12.50.Write forMagnification magni-focuserChart, Price DIVISION

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RAPID SERVICE Large Orders Quickly Proc-essed! Quickly Shipped! Professional supervi-sion of every order. Free estimates on special

problems. Distant points serviced swiftly. Spe-cial stains and techniques available. Fully pro-tected shipments. HISTOLOGY SERVICE, INC.4801 N. Broad St., Philadelphia, Pa. Zipcode19141, (215) DAvenport 4-5800

SCIENCE, VOL. 153

EXPANDINGRESEARCH [kJ

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Ph.D. PHARMACOLOGIST-Basic and applied research in fieldof respiration, including design anddevelopment in the methodology re-

quired. Background in physiology-pharmacology with 0-1 year expe-

rience.

B.S. PHARMACOLOGIST-Be a learning and working part ofthis basic research team, a stimu-lating opportunity for professionalgrowth in research. Background inpharmacy or biology with 1-2 years'experience.

National offers a fine salary andbenefits program with desirableworking conditions. Please DirectYour Resume In Confidence To:

Director of Personnel,

National Drug Co.Div. of Richardson-Merrell Inc.

4663 Stenton Ave.,Philadelphia, Pa. 19144.

An Equal Opportunity Employer.

rI

U

ISCIENTIFICRELATIONS

An unusual opportunity exists atAbbott Laboratories for a Ph.D. inPharmacology, Physiology or Bio-chemistry. Experience in the phor-maceutical industry in a researchand/or administrative capacity isdesirable. The position is for aperson to work in the area re-sponsible for directing all sub-missions to the U. S. Governmentconcerning products in the Abbottline. The individual would be re-sponsible for directing the activi-ties of one of the major sectionsof this department dealing withnew chemical entities. Experiencein the preparation and filing ofIND's, NDA's and experience re-ports would be highly desirable.The person will have broad re-sponsibilities concerning relation-ships within the company andwith the FDA.Our location is suburban withineasy commuting distance of Chica-go. It offers an unexcelled diver-gence of living opportunities, out-standing schools and recreationalpossibilities. Submit resume to:

E. W. Weidenfeller

ABBOTT LABORATORIESNorth Chicago, Illinois 60064An Equal Opportunity Employer

3-aH

mmwlm. lnmc_

.

Introducing the "unflat" TLC plate.This TLC plate is not a conventionalflatglass plate.We say it's "unflat" because we've pre-cision-ground the channel for the absor-bent beds into the plate. This Kontesinnovation provides an easy, accurate,and reproducible technique for thin layerprepa ration.And there's a variety of channel depthsfor quantitative and preparative scaletechniques.No more tapes and feeler gauges, trou-blesome applicators and cumbersomemounting boards. With the new KontesChromaflex'R TLC plates, you just pourthe slurry, then even it with the pre-

cision-ground applicator rod. The chan-nel in the plate and the unground guidingedges control the depth-evenly. Theslurry adheres better and you use lessof it.

Standard Chromaflex plates are 200 x200 mm overall with a 180 mm channeland two reference edges. Channeldepths are available in 125, 250, 500,750, and 1,000 microns - edges arepermanently marked with the properdepth designation.

(There's also a wedge-type plate with agraded depth that decreases from 1,000to 125 microns, and a narrow plate witha 30 mm-wide channel.)

These new Chromaflex plates can befully integrated with our developingtanks, spotting hoods and pipets, recov-ery tubes, sprayers, sandwich techniqueapparatus, storage racks - everythingyou need for a complete TLC system.

Find out more about the TLC systemwith the precision-channel plates. Con-tact your Kontes representative or writefor our TLC Catalog (TLC-1).®)Trademark of Kontes Glass Company

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Regional Distributors: KONTES OF ILLINOIS, Franklin Park, Illinois * KONTES OF CALIFORNIA, Berkeley, California

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For rapid concentration of heat-sensitive mate-rials at reduced pressure. Evaporation rate isapproximately twice that of conventional ro-tating flask devices. Vigorous magnetic stirringaction disperses solution throughout 1000 mlevaporating flask, which is heated by a waterbath in transformer-regulated mantle. Need forrotating joints is eliminated, permitting use ofsimple glass system with joints.The greatly accelerated evaporation rate results from

the large surface of solution, which is dispersed as aconstant spray of small droplets, continuously wettingentire flask wall. The required high speed stirring is madepossible by an efficient, double-magnet bar, driven by apowerful magnetic stirrer. Lock-in effect of double mag-net keeps bar in synchronization with magnetic drive athigh speeds. Addition funnel allows maintenance ofoptimum volume for best dispersion. Condenser flaskcollects up to 500 ml of solvent.

System is entirely of borosilicate glass, connected byI joints. Solution to be concentrated is placed in evapo-rator flask A or in funnel B with Teflon stopcock forcontrolled addition. Agitation is provided by magneticstirrer C and stirring bar D. Evaporator water bath E isheated by mantle F, controlled by variable transformerG. Vapor transfer tube H conducts solvent vapors tocondenser flask J in cooling bath K. Vacuum connectionis made at stopcock of connecting tube L. ThermometersM are provided for evaporator and condenser baths.

Vacuum Requirements. A simple type filter pumprequiring minimum water pressure of 15 to 20 lbs. persquare inch is usually adequate. For solvents of lowvolatility, a mechanical vacuum pump with suitablevapor trap should be employed.

4946-M10. EVAPORATOR, Thomas Magne-Vap,complete as shown in illustration, without filter pump.For 115 volts, 50 or 60 cycles, a.c.; 370 watts.... 205.00

ARTHUR H. THOMAS COMPANYScientific Apparatus and Reagents

VINE STREET AT 3RD * P.O. BOX 779 * PHILADELPHIA 5, PMA., U. S.A.