Page:Reflections on the Motive Power of Heat.djvu/123

Rh 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

&emsp;&emsp; 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

&emsp;&emsp; 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

&emsp;&emsp; $$\tfrac{0.267}{0.000372}$$ = $$\tfrac{1000}{x}$$, whence x = $$\tfrac{372}{267}$$ = 1.395.

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,

&emsp;&emsp; 1.395 units of motive power.

We will now compare this result with that furnished by the action of heat on the vapor of water.