322 PRESSURE IN THE AIR, ETC. 



processes of putrefaction and fermentation- 

 that, as those parts are resolvable into these 

 gases, so these gases (in consequence of certain 

 processes to us unknown) may, in union with 

 oxygen gas, become convertible into that im- 

 mense mass of nitrogen, or azotic gas, of which 

 the greatest portion of the atmosphere is com- 

 posed ;< that as animal and vegetable matter, 

 constitutes the base of hydrogen and carbonic 

 acid gas, so carbonic and hydrogen gas, may 

 constitute the base of nitrogen. The noxious 

 qualities which these gases separately pos- 

 sess, become so neutralised, if I may be allowed 

 the expression, by the new combinations which 

 they have undergone, that they are ultimately 

 lost ; insomuch, that the atmosphere altogether 

 becomes fitted and adapted to answer the end 

 for which it is designed, the nourishment and 

 support of the animal and vegetable creation, 

 and the base from whence illumination, in ge- 

 neral, is produced, and color in particular 



