NEW PRODUCTS
Single compact unit for most metering and feeding requirements...
in
check these features of the new
DURRUM 12-CHANNEL LIQUID PUMP • Compact — the Durrum Dial-A-Pump, Model 12 AP, provides the versatility a n d capacity of 12 s e p a r a t e p u m p i n g channels in j u s t 12" of bench space. • E a c h channel is individu ally a n d continuously ad j u s t a b l e o v e r a r a n g e of 0-4,000 m l / h o u r . • W i d e r a n g e of applications — ideal for feeding of mul tiple c h r o m a t o g r a p h y columns,mixingof liquids a n d slurries, perfusion studies, and p r o p o r t i o n i n g chemi cal s t r e a m s .
The gas thermal conductivity analyzer shown can be used as a gas chromatograph by the addition of adsorb ent filled aluminum columns. De signed primarily for demonstration purposes, the instrument can also be used for chemical research and an alyses. Atomic Laboratories, Inc., 3086 Claremont Ave., Berkeley 5, Calif. 408 Determination of Dissolved Oxygen An instrument for on the spot de termination of dissolved oxygen, the YS1 Model 51, utilizes a polarographie oxygen probe for the determination. A unique feature is a sampler assembly which brings air which is used to cali brate the instrument down into the liquid in which dissolved oxygen is to be determined. Calibration is per formed just before reading and under conditions of temperature and pressure identical to those of the liquid to be read. Calibration can be accomplished in under 3 minutes and results compare within 0.3 p.p.m. with Winkler titra tions. Yellow Springs Instrument Co., Box 106, Yellow Springs, Ohio. 409
• H a n d l e s virtually all y o u r liquid p u m p i n g r e q u i r e m e n t s w i t h one unit cost ing only $750. For more information, contact your nearest representative of Van Waters & Rogers, Inc. or Fisher Scientific Company. Or write for Bulletin 12AP.
C o r p o r a t i o n 9 2 5 Ε. M e a d o w Drive Palo A l t o · C a l i f o r n i a
Circle No. 128 on Readers' Service Card 136 A
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GELMAN
ANALYTICAL CHEMISTRY
The "Sentinel" phototape air monitor shown continuously monitors and re cords airborne particle contamination in clean rooms and other dust-con trolled areas. For 30 days, it oper ates without operator attention giving a complete record of contamination levels. Its strip chart recorder pro vides permanent and legal records. Gelman Instrument Co., P. O. Box 1448, Ann Arbor, Mich. 410
»c& Here's a filter that can take it! One that will save you time, money and patience . . . besides giving you fast, efficient microporous filtration. A significant new Gelman development produces Metricel*, a membrane filter com posed of pure cellulose acetate with no modifiers, gives you a filter that will abso lutely not crack, chip or flake during normal use. Also, it is much more heat stable, more inert than cellulose nitrate filters. Nor is strength the whole story! Composed of microporous cellulose esters, Gelman filters are available in controlled pore sizes from .004 to 10 microns . . . and 85 per cent of the filter is pores! Result: You get rapid as well as efficient filtration from a filter that will not break while you handle it. For the solution to your fluid filtration problems insist on Gelman Metricel* Mem brane Filters. Write for Bulletin 200-11 'Trade Mark, Gelman Instrument Company
GELMAN I N S T R U M E N T COMPANY Ann Arbor, Michigan Circle No. 42 on Readers' Service Card
