MOTIVE POWER OF SEAT. 101 



that which will be required to raise 1 kilogram of 

 air 1 degree would have for its value 0.267. Thus 

 the quantity of heat furnished by the body A is 



0.267 units. 



This is the heat capable of producing 0.000000372 

 units of motive power by its fall from 0.001 to 

 zero. 



For a fall a thousand times greater, for a fall of 

 one degree, the motive power will be very nearly a 

 thousand times the former, or 



0.000372. 



If, now, instead of 0.267 units of heat we employ 

 1000 units, the motive power produced will be 

 expressed by the proportion 



0.267 1000 , 372 



-, whence x = ^-- = 1.395. 



0.000372 x ' 267 



Thus 1000 units of heat passing from a body 

 maintained at the temperature of 1 degree to 

 another body maintained at zero would produce, in 

 acting upon the air, 



1.395 units of motive power. 



We will now compare this result with that fur- 

 nished by the action of heat on the vapor of water, 



