Tables 224-226. 

 MECHANICAL EQUIVALENT OF HEAT. 



227 



TABLE 224. — Summary. 



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

 international du physique, Paris, 1900. 



Name. 



Joule . 

 Rowland 



Reynolds-Morby . 

 Griffiths 



S chaster-Gannon 

 Callendar-Barnes 



Method. 



Mechanical 

 Mechanical 



Mechanical 



Electrical 

 E^t . 

 R 



Scale. 



Latimer-Clark = 1.4342V at 15° C. 

 International Ohm 



Latimer-Clark = 1.4340V. at 15° ) 

 Electrical Eit. I C, Elec. Chem. Equiv. Silver? 

 = 0.001 1 i8g ) 



Electrical Eit. ( Latimer-Clark = i. 4342V. at 15° C. 



Result. 



4-173 

 4-195 

 4.187 

 4.181 

 4.176 

 4.1832 



4.198 

 4.192 



4.187 



4.1905 

 4.179 



Temp. °C. 



16.S 

 10. 



IS- 



20. 

 25. 



Mean- 

 calory. 

 15- 



19.1 

 40. 



TABLE 225. — Reduced to Gramme-calory at 20° C. (Nitrogen thenuometer). 



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

 The mean of the last four then gives 

 1 smaU (20° C.) calory = 4.181 X 10' ergs. 



TABLE 226. — Conversion Factors for Units of Work. 



I joule = I watt 

 per second 



I small 20° cal- 

 ory = 



I erg = 



I kilog. -metre = 



I foot-poundal = 



I foot-pound = 



Joules 

 Watts per 



sec. 

 Volt-amp. 



per sec. 



I 



4.181 



lO-T 



g 

 .04214 

 .042 1 4g 



Small 20° 

 Calories. 



0.2392 



0.2392 X 10-'' 

 0.2392g 

 .01008 



.oiooSg 



Foot-poundals. 



23-73 

 99.22 



23.73 X 10- 



23-73g 



I 



g 



Foot-pounds. 



^3-73 



e 



g 



!1:Z? X 10- 



g 



23-73 



I 



g 



I 



Smithsonian Tables. 



