ON THE COMPOSITION OF SOILS, &C. 201 



" by proper care, might be made as good as 

 " any : but it will be as great a mistake to ima- 

 " gine, that by the use of lime this kind of 

 " soil may be rendered perpetually fertile, as to 

 " think that the other was naturally so ; for 

 " though lime enriches the soil, it does so, not 

 " by adding vegetable food to it, but by pre- 

 " paring what it already contains ; and when all 

 " i^ properly prepared, it must as certainly be 

 " exhausted as in the other case. 



" Here then we have examples of two kinds of 

 " poor soils ; one of which is totally destroyed, 

 " the other greatly improved by lime ; and 

 " which therefore require very different manures : 

 " lime being more proper for the last than dung, 

 " while dung being more proper to restore an 

 " exhausted soil than lime, ought only to be 

 " used for the first. Beside dunging land which 

 " has been exhausted by long cropping, it is of 

 " great service to let it lie fallow for some time ; 

 " for to this it owed its original fertility, and 

 " what gave the fertility originally cannot fail 

 " to restore it in some degree. 



" By attending to the distinctions between 

 " the reasons for the poverty of the two soils 

 "just now mentioned, we shall always be able 

 " to judge with certainty, in what cases lime is 

 ft to be used, and when dung is proper. The 



