CHAP. VI 



OF THE PHENOMENA WHICH ARISE FROM 

 THE CHANGES INDUCED ON THE AIR 

 BY THE LIVING FUNCTIONS OF VEGE- 

 TABLES AND ANIMALS. 



162. IAAVINO, in the foregoing chapters, 

 endeavoured to trace the immediate source of the 

 carbon furnished by vegetables and animals in the 

 several processes above described, and the changes 

 which it effects in" the air that surrounds them, we 

 are prepared next to inquire into the phenomena 

 which arise from, and always accompany these 

 changes. Our conception of these phenomena will 

 be much aided by premising a few fundamental facts 

 regarding the doctrine of heat with which modern 

 chemistry has made us acquainted. 



163. The sensation of heat which we experience 

 from certain bodies, is known to depend on the ope- 

 ration of a power to which chemists have applied 



