Sect. IV. Agriculture and Vegetation. 1 9 



have neither alkaline nor abfbrbent parti- 

 cles in its competition. In this it differs 

 very much from the former foil. 



CHYMISTS generally affert, that clay 

 contains an acid of the vitriolic nature, and 

 an oil. From this acid they account for 

 its diftilling the acids of nitre and fea-falt, 

 and for its vitrefcible nature, as falts are the 

 great affiftants of vitrification. 



LEMERT le fls, in the Mem. acad. 

 de Selene, four /' annee 1708, has thefe 

 words. Comme il y a dans ? argllle de par- 

 ties huilleufes, acides y et terreufes. And again, 

 Car en la poujfent par une feu plus confide- 

 rable, il sen cchappe des acides et de parties 

 huilkufes. Let us fee how far this is true, 



THAT I might difcover its contents by 

 diftillation, 



Exp. 5. I put into the retort half a pound 



of dry clay, taken up feven feet below the 



C 2 furface 



