io The Principles of PartL 



which alone their effects depend. Such 

 fuperficial qualities as that, depend them- 

 felves on the conftituent parts of bodies. 

 We mall then endeavour, by experiment, 

 to detecl: the conftituent parts of thefe dif- 

 ferent foils, and (how wherein they differ 

 from one another. 



SECT. III. 



Of the rick black foil. 



1 Begin with this foil, as it is found to 

 contain the greateft quantity of vege- 

 table food, and as all other foils arc richer 

 or poorer in proportion as they contain 

 more or lefs of this. 



THIS foil, when frefh dug up, and 

 fufficiently moift, has a very agreeable 

 fmell, which is not felt when it is too dry 

 .or too wet. We are very fenfible of an 

 agreeable fmell in the fields after a gentle 

 Shower of rain, efpecially if a drought has 



preceded. 



