76 ARRANGEMENT OF CHEMICAL PRINCIPLES. 



brought in contact with calcareous, carbona- 

 ceous, and metallic substances, and also with 

 water, and by these absorbed or decomposed. 



Conformably to the preceding doctrines, the 

 cultivation of land, naturally is divided into 

 two important opejations,-~viz l /. 



First, TK^^apfi^^mpi'oving^- ox -correcting 

 the^urfac^-of4fee-artl^ -and the sub-soil, that it 

 may receive and regulate a due supply of water, 

 and afford a proper accommodation for the roots 

 of vegetables. . v 



Secondly, The regulating and furnishing the 

 needful supply of food for such plants, ancUfer 

 as it may be desirous to,cultiva1 

 sueh -iai*4&*~a8 the soil is test 



adapted to support. 



To be enabled to form a correct judgment on 

 these points, it will be necessary, first, to com- 

 prehend the nature and properties of the roots of 

 plants, and also of their stalks, branches, and 

 leaves. 



