such areas as nuclear energy, missiles, and space vehicles, are dependent on the availability of standards. At the NBS, the Standard Sample Program now has available more than 600 standard samples, a far cry from the four available when the program started in 1905. Within the past' 5 years, 70 have been prepared and 150 more are being prepared. The variety at present available is shown below:
200:1 ratio of m a x i m u m to minimum speed.
Composition Standards Chemical Steels Irons Ferroalloys Nonferrous Ores Ceramics Primary chemicals Uranium isotopes Subtotal
46 9 8 19 12 19 14 15 Ï4?
Spectrograph^ Steels Al alloys Zn alloys Tins Nickel oxide High temperature Ti alloys Subtotal
95 1 7 10 3 4 3 123
Other Standards Hydrocarbons Radioactive Paint pigments Oils, viscosity pH chemicals Melting point materials Rubber materials Phosphors Other reference materials Subtotal Grand total
186 40 29 12 6 5 17 14 42 35Γ
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NBS is distributing 45,000 samples of standard materials each year to other laboratories for use in controlling chemical processes and in maintaining accuracy of apparatus and equipment. These standards are certified either for chemical composition or with respect to a specific chemical or physical property such as melting point, viscosity, or index of refraction. A complete listing of these materials is given in "Standard Materials," NBS Circular 552 (3rd edition), Government Printing Office, Washington 25, D. C. (35 cents). The need for chemical compounds of certified high purity is becoming of such vital importance that proposals have been made to create permanent organizations to prepare needed compounds and to compile and disseminate information concerning them. Efforts along these lines will be discussed in a forthcoming column.
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STOUGHTON 2 1 2 . M A S S A C H U S E T T S Circle No. 22 on Readers' Service Card VOL 3 1 , NO. 12, DECEMBER 1959
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