14 THE PRACTICE OF THE 



than the earth that lies deeper; for which 

 reafon, gardeners, when making compofts, 

 chufe for that purpofe, the furface of com- 

 mons or paftures, which they find to be the 

 richeft part of thefe foils. The dark colour 

 of the ftaple is from the influence of the 

 atmofphere, to which the furface of the land 

 is moft expofed, and is always richer than the 

 earth below j even though the lower earth 

 be naturally of the fame, or of a better qua- 

 lity than the ftaple. But if this under-earth 

 is brought up to the furface, and expofed to 

 the atmofphere, it will in time be impreg- 

 nated by the atmofphere, and become as rich 

 as the ftaple. It will, however, require time 

 to become as rich as the ftaple, more or lefs, 

 as it is more or lefs ftrong or light, and per- 

 vious to the atmofphere ; for, as before ob- 

 ferved, ftrong, clofe earth is not fo eafily pe- 

 netrated, by the rains, dews, and other in- 

 fluences of the atmofphere ; nor do they go 

 fo deep in them, nor in fo mort a time, as 

 they do in lighter foils, that are more open, 

 and more eafily penetrated by the dews, rain, 

 heat and cold, drought and moifture, of the 

 atmofphere. 



Hence it appears, that the richnefs of land 

 does not confrft in the nature and qualities 

 of the foil itfelf, but in fomethmg extraneous 

 that adheres to it, that is communicated to it 

 by the atmofphere, and that it may be di- 

 vefted of by the roots of plants ; for it feems 



to 



