fb ELEMENTARY AGRlCTJLTtTRAL CHEMISTRY 



through a certain interval a relatively large amount of heat is 

 necessary. The specific heat of water is much higher than 

 that of mercury. The meaning of this statement can be readily 

 understood by considering two experiments. If 1 kilogramme 

 of water at 100° C. be mixed with 1 kilogramme of water at 0° 

 the temperature of the mixture will be approximately 50°. 

 The heat lost by the hot water in cooling from 100° to 50° 

 has just been sufficient to raise the temperature of the same 

 weight of cold water from 0° to 50°. If a kilogramme of water 

 at 100° be stirred with a kilogramme of mercury at 0° the tem- 

 perature of the mixture will be approximately 96*7° C. In 

 this case the water in cooling through only 3-3° C. gave out 

 enough heat to raise an equal weight of mercury through 

 96*7° C. From this result it follows that water requires about 

 thirty times as much heat to raise its temperature through any 

 specified interval as an equal weight of mercury. The specific 

 heat of water is taken as unity, so that the specific heat of 

 mercury will be ^\j-, or -033. 



The specific heat of a substance is thus the quantity of heat 

 required to raise the temperature of any weight of the sub- 

 stance through any interval, compared with the amount of 

 heat necessary to raise the temperature of the same weight of 

 water through the same interval. 



Since water has the highest known capacity for heat, the 

 specific heats of other substances are represented by numbers 

 less than 1 . The following is a lisi of specific heats of various 

 common substances : 



Table of Specific Heats 



