4 1. ;

Here is a light source we believe reelly

worthy of the optical efficiency of the modern

microscope. It achieves the long-sought-after

state of critical illumination at all powers fo-

cused precisely upon the slide. The light enters

the microscape objective at an uncommonly

wide-angle Ai.e.--+igh numerical aperture) pro-

viding resolution of the highest order.

Your first look at a slide so ideally ilhitmi-

nated will be a memorable experience. Let'us

send you- the brochure describing this notable

- contribution to better microscopy.

YOU SEE THE DIFFERENCE...USUAL NARROW ANGLE

T-o -fll objective lens,-lightmust be sharply deflectedwhen striking minute com-ponents under observation.Those incapable of widelydeflecting the beam are notseen clearly.

- SCOPICON, INC.MICROSCOPE LAMP

215 EAST 149th STREET,NEW YORK 51, N. Y.

LOCKED IN PERMANENTLYACCURATE RELATIONSHIP

The microscope Is permanently clamped on thelamp platform, once the initial aligning q4just-ment has been made, it never changes. Carrythe unit anywheret tilt it to the stoeebst angle,if you will; optical alignment .stays flx'd aways.

MM9.

_. ft.

Thej [OI1¶WWWarburg*

fow the procdures ofWARBURG,

SUMMERSON,BARCROFT,

DIXON-KEILIN,DICKENS,

DICKENS-SIMER,GREVILLE,

DIXON-ELLIOTT,ETC.

'This is just one ofover 15.000 items in

the Cenco lIne.

MANOMETRICONThis unit is designed for use in numerous procedures suchas measuring blood gases and investigating reactions ofhemoglobin; measuring respiratory exchange in yeast,bacteria, spores, etc.; measuring lactic acid production innormal and tumorous tissues; and many others.The Manometricon is an especially compact machine and

is designed for simple operation and accurate results. Con-trols and mechanical action are easily adjusted and con-struction is exceptionally sturdy. A constant temperaturebath of 25 gallons is provided having a temperature rangefrom 210 to 600 C. The unit accommodates 20 standardWarburg manometers or 10 Summerson differentialmanometers.A refrigeration unit is also available providing a tem-

perature range of 100 C. to 500 C., plus or. minus 0.05° C.This unit is housed in a cabinet which forms a base forthe Manometricon.

Write for illustrated bulletin containig full details.

CENTRAL SCIENTIFIC COMPANY1700 IRVING PARK ROAD * CHICAGO 13, ILLINOISCHICAGO NEWARK BOSTON WASHINGTON DETROIT SAN FRANCISCOSANTA CLARA LOS ANGELES TORONTO MONTREAL VANCOUVER OTTAWA

Refnry Supply Company < D Tulsa * Houston

November 7, 1952 .1

For new simplicity andconvensce, in using

THIS TIM'E. SAVING,INSTRUMENT-`

in your clinical analyses

A set of 13 laboratory-proved clinical proceduresfor Beckman B andDU

.

The value BeckmB n Spectr otometers in assur- ity resul.t* nximum benefit is obtained from theing greater accuracy nnd speed an clinicalpo s unequalled kaccuracies and superior resolution ofis widely recognized throughout clinical fields. Anal- Beckman Spectrophotometers.yses formerly requiring hours-by conventional These procedures, prepre fron athoria-

methods are now being made accurately in minutes tiva work in the field by Dr. J. W. Mehl, Professorwith Bedcman Spectrophotometers, saving the time of Biochemistry at a leadin miedical school, are pre-of highly-trained personnel and increasing laboratory seated with maximum clat-ity and detail-coverproductivity, principles involved, apparatus used, preparation of

To- further simplify pectrophotometric reagens, step-by-step nmthods and, interpretations ofmethods, Beckman Instruments has ppblished a new results, complete with reference tables and graphs.book detailing 13 laboratory-prov pro;edures for The eotire set of procedures, indexed andmaking basic clinical with Beckman -B and spiral-bound, in a durable cover, is available at the

DU Spectrphotometers. Methods are rediced to a- unusually low price of only $5,00. Write for cu-rapid routin basis withput delays of developing your ICAL SPECTROP*OTOMETRIC PROCEDVRES ... Dataown procedures... greater convenience and simplic- File *22,38.

No other instrumenit in its price range offers features like th se!

Now every laboratory, 1arge or smail, can afford and transmittanc scales' Stray liot Is completely *Hm-modem spetrphotomric advages, bus the nated from 360 to 1,000 millimicrons-is less thanBeckman Model combIn es-for the first time-high 1 % even at 320 milUmicrons. Phototubes are inter-

at pCt ce wwoItI even 0o MOds budget.Model II-imxpe.w .sonve et to use.

that pr.o ld shreol ut h h w e lengt *o Ijl ckman Instrument r -o oetometr '''acc bplete dW'wIte dirjeact I

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BECKMAN INSTRUMENTS Include: pH METERS sid ELECTRODES * SPECTOPRNOTOMETERS * RADIOACTIVITY METERS 'SPECIAL INSTRUMENTS

:Adtzgb, Vol.,126

For simplicity of operation andmaintenance, also for I

.accuracy,oependai/xtiz4j'ci _

A new and morecomplete line of paper

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Complete with electrodes and batteries $145.- Write for CatalogWrite for literature to

PHOTOVOLT CORP. iE95 Madison Ave. New York 16, N. Y.

PYREX INDICATOR SPRAYS

SCIENCE, Vol. 116

I

i

~~~~A A

C & B Reagent Chemicals are manufactured to meetdefinite standards of purity . . . standards which havebeen set up to insure products suitable for research andanalytical use. These standards are based upon the pub-lications of the Committee on Analytical Reagents of theAmerican Chemical Society and our own experience of

.4z= Oover thirty years in the manufacture of fine chemicals.Hy"droxid3A4C.

C & B Products are Distributed byZ-11.4"-.1-X ~Laboratory and Physician Supply Houses

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:___11_Co.',_No- Write for copy of catalog,The COLEMAN & BELL Co.

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. :

Z ! e e _ _ _ w- 3~~~~~~~~£ *

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F11iI~¶aIUIiJiLL'J II ['IAI IAYour Chance to Own a Very Nice Instrument!

IMPORTED MICROSCOPE ,S200 POWERGood optical qualities, fine

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Comes packed in its own hard-wood case. 91/2'' x 41/4" x 3y4/'.

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MAKE YOUR OWNASTRONOMICAL TELESCOPE

See the craters of the moon, the rings of Saturnand the moons of Jupiterl Thousands of amateuirsh:ave tuirned out beauitifTal instruimeflts at a fraction ofthe cost of commercially built ones. You can do thesame. No special skill required. Anid what pride youwill take in an Astronomical Telescope you have builtwith youir own hands. Your telescope will be worth upto $600. Our kits include: PYREX MIIRROR BLANK-PLATE GLASS TOOL--TEMI-PERED POLISHING PITCH- .)

8 ASSORTED EXTRA FINEABRASIVES, ALL IN SHAKER

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Stock # Siz Pstpd. Prie70.003-W ...... 41/4-- .. $ 7.00

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i-.r

Imported20X TELESCOPE

and TripodMachined threaded fittings throughout.Weighs 7 ounces; 6%" closed length.131%/" open length. Achromatic objecthe lens low reflection coated on inside.Makes excellent spotting scope. Swivel-bead tripod is collapsible. 9" high.Stoek #50,007-W .... $12.95 Pstpd.

Instr. -Without TripodStock #50,006-W .... $ 8.95 Pstpd.

ea30jDDAY

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Prtees shown, Individual Focus-for Central Focus add $4 addi-tional to above prices.* All Binocular prices subject20% Federal Tax.

LOOK AT THESE BARGAINS!SLIDE PROJECTOR SETS-Consist of all unmounted lensesyou need to ttal;e the following size projectors:Stock #4029- V-.- mm ..................... $2.85 PostpaidStock #4038-IV .......... 2y4" x 2y".$3.85 Postpaid

Stock #4039-W ..........2 .........½" $3.85 Postpaid

SO-MU-CH for SOLITTUE!SIMPLE LENS KITS!-Kits include plainly written, illus-trated bookIlt showing how you can build lots of opticalItems. Use these lenses in experimentail optics, building,TELESCOPES, low power Microscopes, etc.Stoclt #2-WV-10 lenses ..................... .00,PostpaidStock #5-W--45 lenses ................. 5.O0 PostpaidStock #10-W-80 lenses .........$.... j10.00 PostpaidVON-ABSORBING BEAMl-SPLITTING MIRROR - Latestdevelopment! Oipttecnliy flat to 1/4 wave length. Size:1-15/16" x 2-15/16"-%" thick. Reflects approximately 50%/and transmits approximately 50%. No light is absorbed.Has a th ee-layered film which accomplishes non-absorption.

Stock #567-W ...... ...... $5.00 Postpaid

IP%Im

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Price$39.5045.50

lted) 36.00

Full Grown Performance in a Useful 80 Power

IMPORTEDaBABY MICROSCOPE sONLY 5" HIGHI JUST $4.00 PostpaId!

Students, beginners, or full-fledged lab-men will flind plenty of use for this lit-tle gem. Easily carried. Make minute

inspections: plant and animal life, ma-

terials. metals, etc.-it gives good, sharpdefinitionl Good optical quialities, hinged

base for inielined, easy viewing. easy-to-usepinion focusing. Circular stage, revolvingdisc-light adjustable mirror. A real buyl10-day refuind priv.Stock #50,000-W .............. $4.00 Postpaid

LENS CLEANING TISSUBE-1st quality, sheet size 11" x 7½/".Made to Gov't. spec. Free of abrasives. High wet strength.Stock #721-W .......... 500 sheets .......... $1.00 Postpaid

A Handy, Useful Baralnl

HAND SIGHTING LEVEL

Accurately designed and calibrated.

Indispensable as a hand sighting toolthat projects a level line of sight.IntsIliafe "for -laying -out drains,

ditches, foundations, gardens; forcontour plowing and soil erosion wo.

You will Lse this compact little instrument again and again wherever gmdesmust be established or a level line is necessary over an appreciable distance.

S mple illustrated directions with each instrument;Stock #105-W .$2.50 Postpaid

IF YOU'RE INTERESTED IN OPTICAL BARGAINS Send Cheek or M. 0.

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_~~ ~ ~ I _ _ _ I _ _

I1

November 7, 1952

IMPORTED! 50 POWER POCKET MICROSCOPEmu~~~~~~~~~~~ AlMetal!

Powerfull

U~~~~~5~~~~ ~OnlyPolished Chrome Diagonal Bottom! $ 49

Dozens of Fascinating Uses. Easy to focus. Excellent, postaidstrong optical system. Practical for all sorts of Paminute, close-up examinations. Gives wonderful, sharp, clear magnifleation.Polished chrome diagonal bottom concentrates light on subject. Here's themost compact. handy microscope ever offered at the prica $7 value. Metalbody has hard, gray finish. Instrument weighs approx. 2 ozs. 4% " long.Stack No. 30, 013-W $....... 3.49 Postpaid

S

ELECTROPHORESIS-SCHlIEREN APPARATUS-~~~~~~~~~~~~~~~

x ~~~Routine clinical analysis Macro-prepft&* workcAdsorption c-hromatography Industrial process controlElectrophoresis research & analysis Diffusion & turbidity measurements;_

_ "_ S ,s_ ~~~~~~~~~~~~~~~~-.l .4 : 1 e:.._q%~. mecnanicai aUaiysis

Both models of Aminco Electrophoresis Apparatus constitutecomplete electrophoresis laboratories in single, compact units.They incorporate precise schlieren optics in an air-conditionedspace, automatic integral refrigeration system, built-in line-voltage-regulated and current-stabilized high-voltage powersupply, rapid internal dialysis facilities, and temperature-regu-lated water bath.

Aminco-Stern universal re- Aminco portable model forsearch model for large out- routine research and clini-put and a wide variety of cal use on a smaller scale.sample volumes.

BULLETIN 2175-K BULLETIN 2281-K

D ~~~~PAMERICAN INSTRUMENT COMPANY, INC.

Silver Spring, Maryland * In Metropolitan Washington, D. C.

SCIENCE, Vol. 116

IMMEDIATE DELIVERY' BELLINGHAM & STANLEY

RESEARCH MODEL "A"

EXCLUSIVE FEATURES!

NONCORROSIVE GLASS SCALEBALL BEARING CIRCLEINTERCHANGEABLE POLARIZERHEAD

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ROUTINE MODEL "D" ALSO WITHGLASS SCALE TO .05° .... $450.00

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C. A. BRINKMANN & CO.261-263 GREAT NECK RD., GREAT NECK, N. Y.

6 SCIENCE, Vol. 116

A.H.T. CO. GENERAL LABORATORY PURPOSE

CLEANING COMPOUNDParticularly efficient in removing dried blood, organic

residues and wax pencil marks from glassware

A.N.Tc Totally soluble in hot, cold, hard or soft water.

Not harmful to hands.

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Produces surtaces free from film, streaks and hardwater tleposits.

Penetrates and loosens "frozen" glass joints, stop.cocks and stoppers.

3298.

CLEANING COMPOUND, General Laboratory Purpose, A.H.T. Co. A fine whitepowvder especially formulated for general laboratory use from effective synthetic deter-gents, carefully buffered and blended without use of harsh alkalies or ingredients whichaffect sensitive skin. When used in usual concentration of ',2-ounce to 1 gallon, or in some-what higher concentrationi for stubborn deposits, in either hot or cold water, the pH of thewash water is constant at approximately 9.0 pH.

Contains a surface active (wetting) agent, to Useful for cleaning glassware, porcelain orfacilitate rinsing, which is stable in acids or metal ware, for removing wax pencil marks,alkalies, and a sequestering agent which dis- dried blood, and for making soak solution toperses the metal ions in tap water such as cal- facilitate freeing frozen ground glass joints, stop-cium, magnesium, etc., without precipitation; cock plugs and -glass stoppers. Packed in con-both additives combine effectively to emulsify venient rectangular canisters containing 3 lbs.borganic rsdues,coils and greases,etc., di-

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3298. Cleaning Compound, General Laboratory Purpose, A.H.T. Co., as above described.Per 3 lb. canister, with pourout .......... ................................ 1.55Per original case containing 12 x 3 lb. canisters ...... ...................... 14.88Per 3 original cases (108 lbs.) ........... ................................. 41.85Per drum containing 25 lbs . ............................................. 7.88Per 100 lbs. in 25 lb. drums ........... .................................. 28.37

1 Sample of A. H. T. Co. Cleaning Compound sent upon request.

ARTHUR H. THOMAS COMPANYLABORATORY APPARATUS AND REAGENTS

WEST-.WASHINGTON SQUAREPHILADELPHIA 5, PA.

Teletype Services: Western Union WUX and Bell System PH-72

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Nove'mber 7, 1952 7

2 RESEARCH

BIOCHEMICALISIVSIAINUSForINVESTIGATIONAL USE

WRITE FOR

NEWCATALOGUE

#S975

Listina over 600Research Biochemicals

TYPICAL NBCo. PRODUCTS

AMINO ACIDSA complete selection of more than 90 amino

acids of maximum purity. Including natural L -

synthetic DL and resolved L and D amino acids.

NUCLEOPROTEINS - PURINESPYRIMIDINES

Adenosine Triphosphate * Adenine * AdenylicAcid* Cozymase * Cytidine Cytidylic Acid * Cyto-sine * Desoxyribonucleic Acid * Fructose and Glu-cose Phosphates * Glutathione * Guanine and SaltsGuanylic Acid * Hypoxanthine * Inosine * Nucleates* Ribose Nucleic Acid * Desoxyribonucleic Acid -

Ribose * Protamine * Thymine Uracil * Uridine* Uridylic Acid * Xanthine * Xanthosine.

"VITAMIN FREE" CASEIN(Hot Alcohol Extracted)

A valuable source of protein nitrogen of excep-

tional purity for incorporation into diets to producevitamin deficiencies.

MISCELLANEOUS BIOCHEMICALSAlpha Keto Glutaric Acid * Cytochrome C -

Glutamine * Dopa. Glycogen' Heparin * Lysozyme* Crystalline Vitamins * Crystalline Carbohydrates* Fatty Acids * Growth Factor Analogs * Enzymes* Biological Test Diets * Alkaloids.

..~~......

Radically

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"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. . . . Prac-tically harmless to living cultures. . . . Built with thesame precision as the microscope itself. Over-alllength of lamp, 10". Height, 6¼2". Base, 4¼"/2" x6 ¼2". Price, complete with power unit and 40-wattbulb, $325. Order direct or from leading supplydealers.

Write for Bulletin ZL-321SFISH-SCHURMAN CORPORATION74 Portman Road, New Rochelle, N. Y. kh

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3 INCH EQUATORIALObjective: Coated 78 mm (3") diameter, 1200 mm(47.2") focal length. f/16.Eyepieces: 200 x, 133 x, 96 x, 67 x, 45 x.COMPLETE with equatorial mounting and slow-motioncontrols, setting circles, tripod, eyepieces, sun projectingscreen, view finder, star diagonal, erecting prism system,etc., fitted wooden cabinets.

All Instruments Express collect Only $435Fully GuaranteedssOl

OTHER 2.4 INCH EQUATORIAL .... $225.UNITRON 2.4 INCH ALTAZIMUTH ... 125.

REFRACTORS 1.6 INCH ALTAZIMUTH ... 75.25% deposit required on C.O D. shipments

Send check or M.O. or write for illustrated literature to:

UNITED SCIENTIFIC CO.204-6 Milk St., Dept. R-100, Boston 9, Mass.

SCIENCE, Vol. 116

m

a

electric microtome knife sharpenerBEFORE SHARPENINGnote ragged knife edge.

With the new, simplified Aloe MicrotomeKnife Sharpener the average technicianis able to put a better, smoother, keeneredge on microtome knives, scalpels andother instruments in far less time andwith less effort. One reason for thisquicker, more dependable service is thesimplified knife holder that supports theknife over the full length up to 1 3 V2inches. The holder is set to provide anoptimum bevel for cutting cartilage,paraffin embedded tissue, bone, orsoft metals such as lead.

The special alloy honing wheel is poweredby a split phase, 1/4 h.p. motor. Opera-tion is unusually quiet and free fromvibration. The entire mechanism is en-closed in a rubber-footed, crackle finishcast metal housing with an aluminumplatform. Overall dimensions are143/4" x 12" x 9V2" high.

FIRST HONING removesnicks and rough spotsafter only a few strokeson honing wheel.

improved strop assemblyAn improved strop assembly is now fur-nished as standard equipment with theAloe Microtome Knife Sharpener.It removes the small wire or burr whichaccumulates on the knife during sharp-ening. The strop consists of a high qualityhorse-hide strop and a linen finishingstrop mounted in a heavy metal frame,equipped with thumb screws for adjust-ing tension.

60040- Simplified Aloe Electric Microtome Knife Sharpener, as described, with adjustablestrop assembly, one stick of abrasiye paste, one jar of abrasive powder, one tube of specialsolvent, cord and plug. For operation on 1 1 vvolts, A.C.-each $295.00

aloe scientifIC DIVISION OF THE A. S. ALOE COMPANY

5655 Kingsbury * St. Louis 12, Missouri

COMPLETE HONINGgives fine edge but a finewire or burr mars itskeennoss.

AFTER STROPPING cut.ting edge is smooth andeven; uniformly sharp.

November 7, 19529 9

yES, in spite of production cutbacks on nonmilitary items, E. Machlett & Son can still

offer you immediate delivery on the versatileBarcroft-Warburg Apparatus in both standardand refrigerated types. Designed especially forstudy of micro chemical gas reactions, all oUwBarcroft-Warburg Apparatus possess manyworthy features such as:

* Simple Operation* Compact Design* Durable Construction

Fool-proof Action* Clear, Precise Results

And in addition, the Refrigerated BarcroftWarburg Apparatus has a temperature range ol00 C. to 600 C. (±' 0.050 C.). Refrigerating unilis neatly housed in cabinet which serves as aperfect base for the precision apparatus.

Investigate the many laboratory applicationm1of our Barcroft-Warburg Apparatus. They may

- l be precisely what your laboratory needs. Aci00 O : now, write E. Machlett & Son for detailed descrip

tive literature today.

(_A 1l'52 E.MACHLETT 6 SONEB STL18HO 18 8-

;W/oy-APPARATUS' SUPPLIES ChEMICALS220 EAST 23rd STREET' NEW YOreK 10, N.Y.

Specialists in Warburg Equipment Since 1928

r

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io SCIENCE, Vol. 11 e;

Are you receiving_I. i. . ..f..fi..

0 0 0

INSTRUMENT NEWS is an 8-pagc quarterlypublished in the interests of furthering research,material analysis, and production through mod-ern optical instrumentation. Articles of tech-nical and general interest are prepared by lead-ing workers in the field and the Perkin-Elnmrstaff.

Some of the outstanding articles from the Fallissue are:

NEW RATIO-RECORDING SPECTROPHOTOMETERDescription of Model 13HANDLING LARGE PIECES OF OPTICAL GLASSPrecision Workmanship at Perkin-Elmer

'52

ISOTOPE DILUTION TECHNIQUE FOR INFRAREDArticle by N. R. TrennerCONTINUOUS PROCESS CONTROL WITH INFRARED

Dispersion vs. Non-dispersion Analysers

Among subjects in the Summer '52 issue are:

FLAME PHOTOMETRY SPEEDS INFANT BLOOD STUDIESUltramicro Techniques with Premature InfantsREPORT ON THE SOUTHERaN SKIESDr. Bart J. Bok's results with ADH TelescopeINFRARED ASSAYS SIMILAR DRUGS

Smith, Kline & French Case History

You may receive INSTRUMENT NEWS regularlywithout charge by filling in the coupon below.

THE PERKIN-ELMER CORPORATION| 840 MAIN AVENUE, NORWALK, CONN.I Pease Send me INSTRUMENT NEWS

| NAME . TITLE .. I

.... ...

IADDRESS ...

ICITY STATEI

November 7, 1952

i ws _ v-w_XX ^.Q U I E WARBURG__Es |_!

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IMMEDIATE DELIVERY$675 with Ni. plated copper tank

and glassware clampsG M E-Heav stainles steel tank $45 etaGMEZ-4 FRANKLIN AVE., -MADISON VsWIL

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The N 1: I" Mnnr.i o)a

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ox 1 (IPHTOGRAPH IT...without disturbing setup

Microscope and illuminator are properlyaligned on sliding baseboard. Setup glidesintact into position for visual orphotomicrographic work. Heavy base,specifically designed to absorb vibration,helps maintain precise setup.

Enjoy speed, convenience and efficiencyadvantages of the world'sfinestphotomicrographic equipment-in allthese essential uses:

* Visual microscopy* Photomicrography of transparent

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.~~~~~~~~~~~~~~~~v I1 i ~~~~WRITE

for Catalog E-2 10 andfor advice on yourphotomicrographicproblem. Bausch & LombOptical Co., 642-33 St. PaulSt., Rochester 2, N. Y.

SCIENCE, Vol. 11612