New PRES-sure clip seals PYREX stopcocks against pressure and vacuum Now you can get stopcocks that seal tight enough for pressure and moderate high-vacuum work—at no more than standard stopcock price! The new clip shown above holds the plug firmly against the body to prevent leakage across the bore, or out the top or bottom. Even with this firm sealing you have no trouble valving, since the clip does not affect the plug's rotation.
Four more good reasons to insist on PYREX stopcocks 1 . W i d e choice of designs. Including
PYREX
straight bore, three-way with solid stopper; three-way "T"; two-way mercury seal; high-vacuum type with offset side arms. 2. Rugged design. Molded bodies and extra heavy sidearm tubes are accurately joined. Glass at this juncture is reworked into unusually heavy seals. 3. Precision grinding.Stopcock bodies and stoppers are precision ground to minimize leakage and freezing. All popular sizes are f interchangeable. i . PYREX brand Glass N o . 7 7 4 0 .
Resistant to chemical, mechanical and
thermal shocks. Easily sealed to any PYREX brand Tubing or Apparatus. Insist on the extras you get in PYREX
Labware—the borosilicate line that has been continually developed, expanded and improved for over forty years. The next time you need a stopcock, order PYREX brand from your lab dealer. You'll get this additional PRES-sure clip value at no extra cost. CORNING GLASS WORKS 7 2 - 1 0 Crystal Street, Corning, N.Y.
Corning means research in Glass
PYREX® laboratory ware . . . the tested tool of modern
research
For further information, circle number 29 A on Readers' Service Card, page 101 A VOL. 30, NO. 10, OCTOBER 1958
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29A
