Unit of Heat

—That which is required to raise 1 lb. of water, at 39 degrees Fahr., 1 degree. If 2 lbs. of water be raised 1 degree, or 1 lb. be raised 2 degrees in temper- _ature, the expenditure of heat is the same in amount, namely, two degrees of heat, and to expre the mechanical equivalent of heat, the comparison lies between the unit of heat on the one part, and the unit of work, or foot pound, on the other. The various heat units are as follows: A French calorie=1 kilogram of water heated JC "at or near 4° C: A pound-calorie unit=1 pound of water heated 1° C., at or near 4° C. 1 French calorie=3.968 B. T. U.=2.2046 pound calories. 1 British thermal unit=.252 French calories= -555 pound calories. 1 pound-calorie=1.8 B. T. U.=.45 French calories. 1 B. T. U.=778 foot-pounds=Joule’s mechanical equivalent of heat. 1 Horse power (H. P.)=33,000 foot-pounds per minute. gr 1 Horse power= ee =42.42 B. T. U. per minute. 1 Horse power=42.42X60=2545 B. T. U. per hour. 1 unit of evaporation=965.7 B. T. U.