18 FIRE. [Lesson xxvin. 



appear to be capable of conducting caloric, and 

 fluids also possess the property of conducting it 

 slowly. 



Heat constantly tends to form an equilibrium, 

 by passing from bodies of an higher and diffusing 

 itself through bodies of a lower temperature. 



Two bodies of the same nature, unequally 

 heated, on being brought into contact, soon arrive 

 at an equal temperature, the caloric becoming 

 equally divided between them. But when two 

 bodies, differing in their nature, aad differing in 



* ^ w 



the quantity of caloric they possess, are thus al- 

 lowed to form one common temperature, by com- 

 munication, this will not be found to be an arith- 

 metical mean between the two original tempera- 

 tures ; but the one will be found to have required 

 a greater or less quantity of caloric than the other, 

 to render it of the common temperature. 



In this way it is found that the quantity of ca- 

 loric which raises mercury 38', raises water only 

 12; consequently the caloric which raises the 

 temperature of water 1, will raise that of the same 

 weight of mercury 3.16. The quantity of caloric 

 which a body thus requires to heat it to a given 

 temperature, is called the specific caloric of that 

 body. Thus the quantity of caloric which heats 

 water 1, heats the same quantity of mercury 

 3.16' ; the specific caloric of water is, therefore, 

 3.16 times greater than that of mercury ; and, con- 

 sequently, if the specific caloric of water be = 1, 

 that of mercury must be = 0.31. It is fully 

 established that the specific caloric is different in* 



different 



