128 fbe Principles of Part III. 



but thefe do not arife from attracting and 

 retaining moifture, as thefe powers do not 

 appear to be in proportion to that quality. 



OTHERS think, that the more terrene 

 particles are thofe which nourifh plants. 

 Of this opinion is the famous Tidl; be- 

 caufe, fays he, earth augments them ; and 

 whatfoever augments them, muft be their 

 food. Dung, and other manures, 'act only 

 by fermenting, and fo attenuating the foil ; 

 and are of no more ufe, than, as a knife, 

 to divide their food. But earth alone could 

 never do, without fome more active prin- 

 ciples. Mad Tutt been a chymift, he 

 would have known, that mere earth makes 

 but a fmall part of all plants. Soil may 

 certainly be too loofe. To earth already 

 fufficiently attenuated, manures would do 

 no fervice. Whence the falts and oils of 

 plants? Thefe are objections which the 

 favourers of his fyftern never can anfwer. 



OTHERS 



