NEW PRODUCTS
Breakthrough infineparticle analysis!
The COULTER COUNTER® counts and sizes 100,000 particles in 20 seconds . . . 1 by 1 !
Calibration of Ultrahigh Vacuum G a u g e s A 10_l) torr gunge calibration system consists of a five-foot long, 10-inch diameter,· differentially pumped unit. The system, divided into 5 chambers has four stages of pressure reduction— each stage consisting of the pressure reduction from one chamber to another. Each chamber is pumped by its own vacuum pump. The first chamber uses a mechanical pump, other chambers use diffusion pumps. A McLeod gauge attached to the second chamber serves as a reference standard while the gauge to be calibrated is attached to the fifth chamber. The system is based upon known pressure drops of gases through precisely machined orifices. Three orifice plates (one plate in each of the three pressure reduction stages between the reference gauge and the gauge to be calibrated) with circular holes each of diameters of 3.96, 8.74, and 31.74 mm. can be rotated to bring any orifice-into line with the large bulkhead hole. A simpler, smaller unit for calibration in the ICh7 range is also available. In addition, the company will provide a service to customers for calibrating in this range. National Research Corp., 70 Memorial Drive, Cambridge 42, Mass. 439
* reproducible * 1500 installations * range: .5 microns to 250 microns * from catsup to ores; polymers to contarn in ants . . . whatever the material! C O U L T E R I N D U S T R I A L S A L E S CO.
2S25 N. Sheffield Ave. Chicago 1 4 , Illinois
a division of Coulter Electronics Inc.
Trade Mark
COULTER I N D U S T R I A L S A L E S C O . 2525 N . Sheffield A v e . MRS-8-62 Chicago 14, Illinois
a division of Coulter Electronics Inc. ] P l e a s e s e n d c o m p l e t e d e t a i l s about t h e I Coulter Counter. I Have your representative get in touch for a | demonstration in our office.
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150-mm. glass metering tubes which give a flow range of 0.1 cc./min. to 12 G.P.H. of water and 10 cc./min. to 51 C.F.H. of air are available. Tubes have glass and stainless steel floats and Teflon float stops. A needle valve for fine flow adjustment, individual calibration, special scales, seals, and check valves can be supplied. Flowmeter Bulletin FM-1. Kontes Glass Co., Vineland, N. J. 4 4 0
Here's why more and more scientists depend on Nuclear-Chicago... for their labelled compound needs. Nuclear-Chicago now makes available more radiochemicals . . . at lower prices . . . delivered faster than ever before. H You may choose from 600 radiocompounds of carbon-14, tritium, sulfur-35, phosphorus-32, and chlorine-36. This is the largest selection of such compounds offered by any supplier. Custom preparation service is also available. H Compounds are always packaged in the form offering greatest stability. Same-day shipment is made on 85 percent of all orders. Large stock turnover and careful inventory control mean that only fresh compounds are shipped. And discounts are given for quantity purchases. Ï You are invited to add your name to the mailing list for our new series of informative Radiochemical Bulletins. Let us know your labelled compound requirements: you may phone collect from anywhere in the continental United States.NJC^·».*** n
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351 E. Howard Ave. Des Plaines, Illinois Telephone: 312-827-4456 Circle No. 186 on Readers' S e r v i c e Card
1 6 2 A · ANALYTICAL CHEMISTRY
