of Social Insects, Paris, France. (G. Rich-ard, International Union for the Study ofSocial Insects, Faculty of Sciences, Uni-versity of Rennes, Rennes, France.)

10-12. Thermodynamic and TransportProperties of Fluids, conf., IUPAC, Lon-don, England. (Institution of Mechani-cal Engineers, 1, Birdcage Walk, West-minster, London, S.W. 1.)

10-17. International Union of Crystal-lography, 4th genl. assembly, Montreal,Canada. (G. A. Jeffrey, Chemistry Dept.,Univ. of Pittsburgh, Pittsburgh 13, Pa.)

11-13. Applied Cytology, EuropeanSymp., Brussels, Belgium. (Secretary,Comm. on International Cong., AmericanCancer Soc., 521 W. 57 St., New York19, N.Y.)

14-19. International Assoc. of Geron-

power or utilities. Immune to environ-ment, it can be placed anywhere, regard-less of vibration, temperature, air cur-rents or levelling.

The Cahn Electrobalance weighs less than12 pounds and is enclosed in an alumi-num case with an attractive blue-graybaked enamel finish. Its value is notlimited to present day micro techniques.You may find it advantageous to re-evaluate other larger scale operations.

cer, Internatl. conf., Glasgow, Scotland.(A. P. M. Forrest, Dept. of Surgery, West-ern Infirmary, Glasgow, W.1.)

8-12. Inter-American Cong. of Philoso-phy, 5th, Washington, D.C. (R. M. Chis-holm, Brown Univ., Providence, R.I.)

8-12. Poliomyelitis Conf., 4th inter-natl., Geneva, Switzerland. (Secretariat,4th International Poliomyelitis Confer-ence, Hotel du Rhone, Geneva.)

9-11. Biological Symp., 8th annual,Univ. of Michigan, Ann Arbor. (B. L.Baker, Dept. of Anatomy, Univ. of Michi-gan, Ann Arbor.)

9-13. European Molecular, Spectros-copy Conf., Freiburg, Breisgau, Germany.(R. Mecke, Dept. of Physical Chemistry,Univ. of Freiburg, Freiburg.)

9-13. International Cong. for the Study

The Cahn Electrobalance is easy to oper-ate, fast, rugged and portable, yet hasaccuracy equal to many delicate microbalances. Balancing time takes but a sec-ond or two. Complete weighings averageless than a minute. Readings are takendirectly in micrograms.Controls are simple to understand. Sam-ple weight is balanced by torque appliedelectrically in a magnetic field.This electric micro balance is completelyself-contained, requiring no external

WIDE RANGEOF

SAMPLEWEIGHTS

PRICE: Number B-1364X Caln Electrobalance complete with three batteries, two stir-rups, ten disposable aluminum pans, tweezers, a set of calibrating weights (one for eachrange-5, 10, 20 and 50 mg.), and an instruction manual. Overall size: 12" h x 10 w x7" d. ...................$615.00

New 4-page brochure gives complete details. Write for your copy today!

Precision Is 0.02%, accuracy about 0.05% of full scale on each range. Aecuracy on thetwo lower ranges Is within the tolerance on Class M weights, the most accurate selentiflcreference standards made. You can use this balance for the most critical work.

1100

tology, Merano, Italy. (A. I. Lansing,Dept. of Anatomy, Univ. of Pittsburgh,Pittsburgh 13, Pa.)

14-20. Clinical Pathology, 4th internatl.cong., Brussels, Belgium. (M. Welsch,Service de Bacteriologie et de Parasitolo-gie, Universite de Liege, Blvd. de la Con-stitution, Liege, Belgium.)

15-18. Biochemistry of Lipids, Interna-tional Colloquium, Oxford, England. (Dr.Sinclair, Laboratory of Human Nutrition,Oxford.)

15-19. Institute on College Adminis-tration, annual, Ann Arbor, Mich. (A. D.Henderson, 2442 U.E.S., Univ. of Mich-igan, Ann Arbor.)

16-19. American Malacological Union,annual, New Haven, Conn. (Miss M. C.Teskey, P.O. Box 238, Marinette, Wis.)

16-24. International Cong. for Pureand Applied Chemistry, 16th, Paris,France (R. Morf, Secy. Genl., IUPAC,Sandoz, S.A., Basel, Switzerland.)

20-21. Medical-Sociological Aspects ofSenile Nervous Diseases, internatl. symp.,

Venice, Italy. (S. N. Feingold, JewishVocational Service of Greater Boston, 70Franklin St., Boston 10, Mass.)

21-28. Neurological Sciences, 1st in-ternatl. cong., Brussels, Belgium. (P.Bailey, National Institutes of Health,Bethesda 14, Md.)

23-24. Modern Electrochemical Meth-ods of Analysis, Internatl. symp., Paris,France. (G. Charles, Ecole Superieure dePhysique et de Chimie, 10, rue Vauquelin,Paris 5e.)

25-26. Structure Properties Relation-ships of Polymers (IUPAC), Paris, France.(International Union of Pure and AppliedChemistry, 4, Avenue de l'Observatoire,Paris 6e.)

25-29, Protein Chemistry Symp.,IUPAC, Paris, France. (J. Roche, Col-lege de France, Place Marcellin Berthe-lot, Paris 5e.)

26-27. Experimental Psychology andAnimal Behavior Section of InternationalUnion of Biology, Brussels, Belgium. (H.S. Langfeld, Dept. of Psychology, Prince-ton Univ., Princeton, N.J.)

26-27. Linguistic Soc. of America, AnnArbor, Mich. (A. A. Hill, Box 7790, Uni-versity Station, Austin 12, Tex.)

26-27. Military Psychology, internatl.symp., Brussels, Belgium. (National Acad-emy of Sciences, 2101 Constitution Ave.,NW, Washington 25.)

26-1. International Congress on Nu-trition, 4th, Paris, France. (QuatriemeCongres International de Nutrition,CNERNA, 71, boulevard Pereire, Paris17e.)

28-1. Psychoanalysis, 20th internatl.cong., Paris, France. (Dr. Nacht, 187,rue Saint-Jacques, Paris 5.)

28-3. Psychology, 15th internatl. cong.,Brussels, Belgium. (L. Delys, 296, avenue

des Sept Bonniers, Forest-Bruxelles.)31-5. International Assoc. for Hydrau-

lic Research, Lisbon, Portugal. (M. Co-elho Mendes da Rocha, Laboratorio Na-cional de Engenharia Civil, Avenida doBrasil, Lisbon.)

31-6. Dermatology, 11th internatl.cong., Stockholm, Sweden. (C. H. Flo-den, Hudkliniken, Karolinska Sjukhuset,Stockholm 60.)

( See issue of 17 May for comprehensive list)

SCIENCE, VOL. 125

Range Sensitivity Accuracy

0-5 mg. 1 microgram 2.5 micrograms0-10 mg. 2 micrograms 5.0 micrograms0-20 mg. 5 micrograms 12.0 micrograms0-50 mg. 8 micrograms 30.0 micrograms0-0m.8mcorm 00mcorm

Unmatched flexibility of movements in all directions inspace are achieved by natural hand movements undermagnifications of 100 X to 2000 X without adjustment.The "Cailloux" advanced design combines maximum speed,precise response and stability with unusual ease of oper-ation. Back-lash, parasitic vibrations and lag are elimi-nated. Prolonged manipulations con be conducted withoutfatigue. Includes many additional exclusive features.

LOW IN PRICE

W _ _ _ _0

31 MAY 1957 1101

PHIPPS & BIRD

- 1l~l|PIPETTE DRYERIn the laboratory, this large capacity Pipette Dryer is particularlyrecommended for the thorough drying of pipettes of any size up to375 mm. in leng......... Cylinder is mounted on vented base with spe-cially designed heater in lower end of cylinder. This instrument isdesigned to take the standard rack of a 6" pipette washer. Rack istaken out of washer, drained for about a minute, then placed rightinto the Dryer. This method of drying means less handling by thetechnician, thus greatly reducing the hazard of breakage. Completewith cord and plug, but without rack. 115 volts, AC or DC

Without obligation, send us complete in-Cat. No. 71-731 Cat. No. 71-726 formation on your Pipette Dryer.

$45.00 $12.00.Name ..Title.

mUU.La u~as Dme Company .Manufacturers & Distributs of Scientific Equipment Address./S7 6th & Byrd Streets - Richmond, Va. Cit .....-........ ....... State.

31 MAY 1957 1101

EQUIPMENT NEWSThe inforroation -epo ted he e is ob-

tained from mtanufacturers and fromtother sources considered to be reliable.Science does not ass ti e responsibilityfor the accuracy of the information. .Allinquiries concerning itemts listed should1)c addrossed to scincie, Room 740, 11W1. 42 St., New York 36, N.Y. Includethe name(s) of the tartufacturer (s and(the department nurnber(s).

* IiTR.IATIIN U NiTS for removal of lii-

sutit particles fromt xwater have capa(cities.9rlanging from 3 to 10( gal/miitii. The fill(-Itess of particle retnoval rainges from0.1 to 2.5 it. (Heico Inc., Dept. S354

* SF;F PiNG ()OSCtLIATOR covers the ranlgeOf frequetie ies from 1(000 to 13)000 Mey/Aec With a powter outt)ut of fromll 1(0 mccto 1 w by means of sevent interchangeableunits. Used lit onjciItc tion with the mIan-

ufac tlrlrS rI1)id-scail Rattioscope, theoscillator mcakes pJossible direct and ill-stantaiscous measuremetnts of i eflectionand transmission coefficietws, directlyviewable on an oscilloscope, cliininait inlgthe need for point-by-point ineastire-ments or for miaintaining 'a constantpos-er input to the dev ice cinder test.Polarad Electronics Corp.. )Pept. S35 1)

* tA c;NP NI iRi' coated xcitli Tefloni isbeing offered is a kit for research anddevelopment cise. The kit contains an as-so(irtimienit of 1 2 spools of x ilre in gagesaize s 2(2 through 42 A.W( ;. T(,t-meolit'.5ip(alt ies In(., Dept. S365,

* 1AGNF iTiC-iTAPF ItANiLI FR Consists often separate identic al tunits or bins, eachwcith a capac ity of oxer 8 x 10e)' bits. Eachbin normally onailns 500 ft of -ii. xwidenagileti tLape for 4-channel rcordingll(ccith 2(0(0 pulse/in. density. Eac h bin is

in balances...>4

Easy, accurate weighingwith Ainsworthchainweight balances

-The chemists I talk to all knocthat it is easier and faster to operate a

chainweight than to fiddle witha beam rider and small milligram wveights.'They realize too that a chainweightis not a unit of mass - just a variablewveight calibrated to the balance.

The calibration takes sonse doing,and here are some of 'the little thiisgsthat count,' on AinsworthChainweight Balances, which resultin easy, fast, and accurate weighing"free hanging chain

"sapphire jewel and adjustable pivotmounting

"chain suspended from graduatedtape (you can't move the tape x'ithoutmoving the chain)

"ball bearing pulleys"direct drive'solid 14K gold chain"

Just call your laboratory supplysalesman..-he can give you more

information about Ainsworthproved and improved balancesand weights..

or write for free catalog

.IT'S L1THTELa

UNG1dCoUNT

-'_SEi1102

qcluippedl w ith its ownH ' 'd-lavbackheadwc hi( h may be scwitehedl l)y relay, toa coImmSSll otitput. )ual spceds of 30 or6( in. Sc( or other combinations are pro-vided. Potter Ilnstrume(nt Co., tIu(.Dept. S362)

S11.1i(ON of seimsic oideuctor grade is CoiI1-inercialiv available. Three gfrades, re-.SCalre, pie(mliuillm, Stand standard, \xill l)eimarketed. Tihe research g-rade has a re-sist ivitx gvieater thant 2110 ohm (tO andimpnrit colntent l(-ss thani 1 part in 1W.Miiiiissluin resis~t ivit of the premiumgrade is 1(0(0 ohm cm and of the stand-atrcl grade 1 0 ohmn ( if. I exas I ostro-mnnt.S, 1nc., D)ept. S3.56)"

* FiN\i -i T. STiING si.'1' is based on the factthalttneither index of ri-frat( tion 1nor Spe'-cific gravitv separately xw ill identify a

gem l)tit thlt together t bh-se plropertiesx'iii identify a germ with ertainty. 'Theset includes a 'Refraetos(cope n(d x i tlisix inde x-of-re fraetioni liquids and a setof nine specific-gravitv liquids. R. P.

( aroil le alt)ormtorles, Il t.. 1)ept. S357)

* Ri I)/i ItNt(t N it'U ITuilles 300( 3-nil

scrtmi bottles siimiulta.niotisly Ihe traysupi)on xw hich samtlples aie1ela.Ced revolveoItCt(-1eah inintite in front of aI radianlit-hIlatilln sotirce to heat all samples uni-fiInkl-. A tilting-txype Mc Leod gage fur-nlishes Va.(it(cic Il- eastiotn t D1imeisions of the Unit IIre 12.5 by 2) Ii.)b 1 5.5ill. ElX,. MaI\chle'tt and Soii, IP)ept. S I 58

Si IN ILFESS SiFitL FiASKkS, itisnlatedxith light-weight, rigid, losecl-eell pllas-tic, are said to provide insnlatiiig paroper-ties stiperioir to vatctinm flasks. T'het steelflasks, of \ ide-monuth design, are iavail-able ill 2-, 4- and 8-lit capacities. (.,M aehlett and Son, Dept. ,S360()

I* i)St ii ost oii (covers thn- freccliuencyr-aInge fromn dirt-ct ('currelit to bev('ICnd 50M y/sec. X(Sxeep calt be drive n at repeti-tion rates as high as 25(1 kcy'/sec and as

|slox ly as (1.02 se( 'The 1-axis ampli-licr is a three-stag' direc t-coupled type.Other features inel ide It p)lse risc' timetiof 7 m acs(-(-ttenuator rangcs froIm 0.2to 2(0(0 v fcill scale anird an a-c d.-e. svn-chronlizing cirt cuit that p m 'lec tctiollof the portion of the syn throcniuing signalfircim which to trigger the sw ccl). Theoscilloscope is built up of six inteirc lange-able units. All operating voltages arerg(t-llated. 'Allen B. 1D)tAmi[t 1 abcii'a-tories, Ise., Dept. S350)* NUCcI FASR PcOW F.R s-ACc KS 11'( capab)l ofI le-liverin, (-nergy puls s up to 337,00(1

(-1rt'S. The powc cr paclk is based on a

* itilcIcat battery wc hich convserts nuclclearn-ox1(~ dirt-c tly intci cl-etric c-nergy ill

cirrc-nt ratings from to (1(100 tia andeqtiilil)i itim voltagis in the order of 10kx'. The battery cutrretIt is tised to charge

SCIENCE, VOt. 125i.

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