Tables 210-213. 

 MECHANICAL EQUIVALENT OF HEAT. 



TABLE 210. — Summary of Older "Work. 



197 



Taken from J. S. Ames, L'equivalent mecanique de la chaleur, Rapports presentes au congria 



international du physique, Paris, 1900. 

 Reduced to Gram-calorie at 20° C. (Nitrogen thermometer). 



• Admitting an error of i part per looo in the electrical scale. 



The mean of the last four then gives 



1 gram (20° C) oalorle = 4.181 X lO' ergs. See next table. 



X gram (15^ C.) calorie =: 4.1S5 X 10' ergs assuming sp. ht. of water at 20° ^o.gggo. 



TABLE 211. —(1923.) Best Value, Electrical and Mecbanlcal Equivalents of Heat. 



The following values have been adopted for the International Critical Tables, prepared under 

 the auspices of the International Research Council, 1923. 



g (20° C) calorie = 4.180 international electrical joules 



= 4. 181 X 10^ ergs 

 g (15° C) calorie = 4.185 X 10' ergs 

 The equivalance, i 20° calorie = 4.183 joules, is so widely used it has been thought best to retain 

 the following table computed with it as a basis: 



TABLE 212 — Conversion Factors for Units of Work. 



The value used for g is the standard value, 580.665 cm. per sec. per sec. = 32.174 feet per sec. per sec. 

 * The values thus marked vary directly with " g. " 

 t The values thus marked vary inversely with " g. " For values of " g " see Tables 563-567. 



TABLE 2I3. — Value of the English and American Horsepower (746 watts) in Local Foot-pounds 

 and Kilogram-meters per Second at Various Altitudes and Latitudes, 



Smithsonian Tablcs. 



