TESLA ELECTRON MICROSCOPE-Desk Model BS 243Guaranteed

Local Service

Installationand

InstructionIncluded in Price

FEATURES* Resolving power 30A to 50A in routine operation, opti-

mal resolution 25A* Magnification 1,OOOX to 30,000X, adjustable in steps

* Accelerating voltage 60 kV ±0.01%* High-voltage stability better than 10', ripple less than

2.5 x 10-5* Specimen inserted under vacuum

* Specimen motion controlled from microscope platform

* Microscope may be tilted for stereo-photography* Viewing port usable for diffraction patterns* Uses standard 35 mm film (36 pictures) or ten 2" x 2"

plates* Dimensions of basic instrument: 141/2" wide, 18" deep,

341/2" high* Low initial cost and minimal maintenance

Made inCzechoslovakia

WorldwideDistribution

For Complete description,technical data,

and ordering information,write for BULLETIN 8-2000

by by EXCLUSIVE SALES AND SERVICE IN U.S.A.

AOYO NATIONAL INSTRUMENT LABORATORIES, Inc.828 Evarts St., N.E., Washington 18, D. C. Tel.: NOrth 7-7582

758 SIENC, VO. 13

The LittleGiant

60 kV30,OOOX30A

.1

SCIENCE, VOL. 132758

worth a thousand words... iLet your students see science in actiomfor themnselves iwith these laboratory-provededucatio'nal instram)ents byBausch, & Lo))mb. They'll uncderstandcbetter, faster-be eager.to lear)n more.

B&L STANDARD TEACHING* MICROSCOPES. Standald size and operation; sturdy,

precision construction at school budget prices. ! B&L STEREOZOOM* MICROSCOPES with

continuously var iable or fixed magnification. Colorful, erect 3-D images give new life to any subject.

' B&L MACROSCOPES* are ideal for gross studies, field trips, dissection. Easy focus, large

fielcl of viewv with 10 x, 20 x, or 40 x magnification. TRI-SIMPLEX* MICRO-PROJECTOR

prepares students for individual microscope study. Projects slides or live specimens to wall screen

nl to table-top for tracing. BALOPTICON* PROJECTORS give big, bright, lasting views

of slides, opaque objects, even chemical reactions. cA B&L SPECTROSCOPES. Basic chemical

analysis tools; show spectra of elements. STUDENT-PROOF construction of all instruments gives

years of service at a cost to fit any school budget. WRITE for Catalog E-152; demonstration on

r equest. No obligation, of cour se. Bauschl & Lomb Incor-porated,75M909 Bafusch Street, Rochester 2,2lNew York.

Tr c(( k1, JIusch &S LoWil) Ioco ll itf dO 1- L~ %- X,IV L.. I1 -