ARITHMETIC 



297 



1 B. T. U. = .252 calorie and 1 calorie = 3. 968 B. T. tJ. 



One small, or gram, calorie (a heat unit also in some use) is 

 the quantity of heat required to raise the temperature of 

 1 gram of water 1 C. at or near 4 C. 



CENTIGRADE AND FAHRENHEIT DEGREES 



