C 1^5 i 



ground-work of all certainty in this matter. Theo- 

 ries not built upon and fupported by experiments 

 . are matters of mere amufement, and have no ex- 

 iftence but in the imagination. Unfortunately, 

 experiments have been publilhed by the thoufand, 

 which bear the cleareft internal evidence of their 

 never having been made but upon paper. Such 

 writers fhould be regarded as the fliarks of fociety, 

 who would facrifice truth, miflead mankind, and 

 impofe upon the publick, to pocket a little money. 

 But to proceed with our enquiry. 



The principles of vegetation, and the means by 

 which it may be promoted in the moft fuccefsful 

 and beneficial manner, may be fitly divided into 

 three general heads, and diftinguiftied by the terms 

 mechanical, chemical^ and nutritive. The mechanical 

 includes every operation which tends to break, di- 

 vide, and pulverize the foil; whether it be by 

 ploughing and harrowing, digging and hoeing, or 

 by any other means whatever; that being the moft 

 eligible which moft effedlually performs the operaw 

 tion at the leaft expence. 



Pulverizing the foil may be truly confidcrcd as 

 the firft ftep towards an improving vegetation; not 

 as producing the food or nouriftiment of plants, but 

 of putting the foil into a fit condition for receiving 



M 3 it, 



