NEW PRODUCTS T h e sinks a r e produced in aluminum molds, which ensure dimensional sta bility. Cover corners a n d a b o t t o m dished t o t h e outlet p r e v e n t accumula tion of c o n t a m i n a n t s in corners or liquids on t h e b o t t o m . D u r i r o n claims t h e following features for i t s p r o d u c t . D u r c o n sinks, offer resistance to corrosion, abrasion, a n d heat. T h e y withstand mechanical shock, a n d tests provide assurance of service without cracking, spalling, or other forms of failures. T h e y a r e i m permeable t o liquids, moisture absorp tion in 48 hours being n o t more t h a n 0.06%. T h i s p r e v e n t s possibility of p e r m a n e n t staining b y dyes. T h e y are lighter in weight t h a n competitive m a terials a n d t h e j e t black color blends well in a n y l a b o r a t o r y . T h e r e a r e 12 s t a n d a r d sizes a n d spe cial sizes can b e fabricated as desired.
Is it PPO... PBD... or POPOP?
P-21 Vacuum Pump
Easier to use because they're harder to break!
PYREX® Needle Valve Ware with double-thick stems Stem walls are twice as heavy as conventional walls—twice as dur able! Two valve sizes are available: small (with 2 m m bore) and large (with 4.7mm bore). You get ultra-precise control of fluid flow with P Y R E X N e e d l e Valves. A n d their fine-ground flanges assure a better seal, par ticularly under pressure. The famous chemical stability of PYREX brand glass N o . 7740 helps prevent contamination. Valve body and retainer rings are pure TEFLON*.
Needle valves and connecting tubes can be purchased separately; or in PYREX bu rettes, distilling heads, funnels, chroma tographic tubes and stopcocks; or in special ware fabricated to your needs. For sizes and prices, see your PYREX Laboratory Glassware Catalog, L G - 1 . *T.M. for Du Pont Tetrafluoroethylene Resin.
CORNING GLASS WORKS 6 9 Crystal Street, Corning, N e w York CORNING MEANS RESEARCH IN GLASS Circle No. 52 on Readers' Service Cars'
A new internal valve two-stage m e chanical v a c u u m p u m p is announced by Precision Scientific C o . Model 75 v a c u u m p u m p h a s free air capacity of 75 liters p e r m i n u t e . T h e c o m p a n y says it features quick s t a r t ing, quiet operation, easy t o clean de sign, a n d a n attainable v a c u u m down to 0.1 micron. Other features claimed are reduction in oil leakage, free p a s sage of air t h r o u g h oversize p o r t s , a n d an enlarged cored pocket in t h e i n t a k e to t r a p foreign particles a n d reduce oil b a c k u p . Precision Scientific recommends use in t h e l a b o r a t o r y for v a c u u m ovens and for depositing films a n d coatings, degassing or concentrating liquids, freeze-drying, distillations a n d other purposes. P-22
High Resistance Bridge M i d - E a s t e r n Electronics, I n c . h a s a megohm bridge for calibration of high megohm resistors, t o close tolerance. T h i s bridge covers t h e range from 1,000 ohms t o 1.1 X 1 0 " ohms. I t is b a t t e r y operated, a n d is enclosed in a solid oak case. A set of nine plug-in l a b o r a t o r y s t a n d a r d resistors as well as a b a t t e r y supply in matching oak case a r e provided as s t a n d a r d . Accuracy is b e t t e r t h a n 0.2% u p t o 10 1S ohms, according t o t h e company, a n d t h e test potential is continuously variable u p t o 1,000 volts. T h e megohm bridge will find a most valuable use, i t s m a n u f a c t u r e r believes, in t h e nucleonics field, since a n y d e vice for measuring very small ioniza tion currents makes use of resistors in the range of 10 8 t o 10 1 4 ohms. P - 2 3
I n this picture, P O P O P has been photographed under ultra-violet light, dissolving in a beaker of toluene. If you guessed right, consider yourself among t h e initiated. P P O , PBD, a n d P O P O P are scin tillation grade fluors, known chem ically as: 2, 5-Diphenylnxazole PhenylbipheMyloxadiazole-I, 3, 4 p-Bis [2- (5-pienyloxazolyl)]-benzene
Produced by Pilot Chemicals, Inc., they're the purest available, with m a x i m u m light output a n d high melting point. But d o n ' t take o u r word for it. Send us your n a m e a n d title a n d we'll send you a free sample of any one of t h e three.
Other Pilot Fluors Always in Stock: BOPOB-p-Bis[2-(5-p-biphenylyloxazolyl)l-beitzene BB0-2, 5-Dibiphenylyloxazole DiphenylaceMene 9, lO-Diphenjlanthracene p, p'-Diphenylstilbene ALPHA-NP0 — 2-
