The Principles of Part III, 



Cor. 3. As the north wind is obferved to 

 bring moft of the nitrous acid, it would 

 feem to follow, that banks which have a 

 north afpect mould receive moft of it. It 

 is obferved, that they are, in general, richer 

 than thofe of a fouthern afpeft. As the 

 former have not fo much fun as the latter, 

 they mould be lefs fruitful : but our theory 

 of vegetation affords a fufficient reafon for 

 this fadt. 



Cor. 4. It appears, from the manufacture 

 of nitre, that all thofe abforbent meagre 

 earths ufed in agriculture, will be rendered 

 more capable of anfwering their purpofe, 

 by an addition of fome putrid fubftance, 

 vegetable or animal, to open their texture, 

 and make them more pervious to the in- 

 fluence of the air. Hence the advantage 

 of mixing animal or putrefied vegetable 

 fubftances with chalk, marl, lime, or the 



afhes of vegetables. 



Cor. 



