7£e&c&nca Φιοφΐ€&& New International Tempérâture Scale On J a n . 1, 1049, the National Bureau of Standards Segan using the definitions of the Interri .t-ional Temperature Scale of 1948 both, in its own research program and in calibrating instruments for other scientific and industrial purposes. Based on a draft prepared by m e m b e r s of the bureau staff, the new scale was a d o p t e d at Paris by the Ninth General Conference on Weights and Measures in October 1948, and the official t e x t was approved for publication before t h e e n d of the year. This is the first revision of the International Temperature Scale since its adoption 21 years a g o . T h e experimental procedures by which the scale is t o be realized a r e substantially unchanged; but certain refinements, based upon experience, have been incorporated to make the scale more uniform a n d reproducible. The experimental difficulties inherent in the measurement of temperature o n the thermodynamic scale (an ideal scale based on energy changes i n a Carnot cycle) led to the establishment in 1927 of the practical scale known as t h e International
T e m p e r a t u r e Scale. This scale is based upon six reproducible equilibrium temperatures, or ''fixed points," to which numerical values are assigned, and upon specified interpolation formulas relating temperature t o the indications of specified s t a n d a r d temperature-measuring instrum e n t s . The scale is designed to conform, a s nearly as practicable, to the thermod y n a m i c Celsius scale as it is now known. A t the present time, however, it is possible t o obtain values of temperature on the International Temperature Scale more accurately than on any thermodynamic scale. T h e six fixed points of the 1927 scale were * the boiling point of oxygen ( — 182.97° C ) , t h e freezing and boiling points of water, the boiling point of sulfur ( + 4 4 4 . 6 0 ° C ) , the melting point of silver ( + 9 6 0 . 5 ° C ) , and the melting point of gold ( + 1 0 6 3 ° C ) . F r o m - 1 9 0 ° to + 660 ° C , t h e measure of temperature was based on t h e indications of a standard platinum-resistance thermometer used in accordance with specified formulas. From + 660° C. t o the gold point, a platinump l a t i n u m rhodium thermocouple was the reference instrument; a n d above the gold
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point, the optical pyrometer h a s been standard. The same fixed points, with one slight modification, are specified in t h e 1948 scale, and the laboratory procedures · for obtaining temperatures between fixed points are essentially the same a s those previously used. Only t w o revisions i n t h e definition of the scale result in a p preciable changes in t h e numerical values assigned to measured temperatures. O n e of these is t h e change i n t h e value for t h e silver point from 960.5° t o 960.8° C , which affects temperatures m e a s u r e d with the standard thermocouple. T h u s , in the range between 630° and 1063° C , numerical values of temperature a r e higher t h a n on the 1927 scale, t h e maxim u m difference being about 0.4 degree near 800° C. The adoption of a n e w value (1.438 cm.-deg.) for the constant c 2 in t h e radiation formulas changes a l l temperatures above t h e gold point. I n t h e new scale, Planck's radiation formula is specified instead of Wien's for c a l culating temperatures above the gold p o i n t a s observed with an optical pyrometer. Since Planck's law is consistent with t h e thermodynamic scale even at high t e m peratures, this change removes t h e upper limit to the scale formerly imposed by t h e use of Wien's law. There are several o t h e r i m p o r t a n t modifications in the scale which cause little or no change in numerical values for temperatures but serve to make t h e temperatures more definite a n d reproducible. For example, the s t a n d a r d platinum resistance * thermometer is to be used a s a reference instrument from the oxygen point to t h e freezing point of antimony (about 630° C ) , rather t h a n over t h e range from —190° to 4-660° C. Platinum of higher purity is also specified for the standard resistance thermometer and standard thermocouple, a n d smaller permissible limits are given for t h e electromotive force of the standard thermocouple a t the gold point.
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dried natural horse serum, which is free-flowing, macrocrystalline, stable, and easily handled, is one of a series of J a p a nese veterinary medicines described i n report PB-95825 (photostat $2.50, microfilm $1.75, 16 pages). T h e report describes a number of the medicines m a d e by the Japanese from native raw materials or waste products such as fish materials (whale a n d sardine oil, fish meal), silkworm products, soya bean oil, and cocoa b u t t e r . Available from the Library of Congress, Photoduplication Service r Publication Board Project, Washington 25, D . C. Orders should be accompanied b y check or money order payable to the L i b r a r i a n of Congress.
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