TRENCHING. 143 



making an excavation for a sunk fence, or for some 

 bit of road leading to a field, and where the sur- 

 face mould, being generally kept in a puddled con- 

 dition, is there an inconvenience and of no use 

 whatever. A great deal, in most cases, might 

 thus be collected, and often would be were its value 

 justly appreciated. Such heaps, when mingled 

 with lime in the proportion of one of lime to six of 

 earth, constitute a manure which, taking bulk for 

 bulk, is equal in value to the best dung; and having 

 this additional advantage, that as its substance can- 

 not be consumed, it adds depth to a thin soil, and 

 communicates an everlasting benefit. 



The great advantage of a deep soil, besides the *, 

 more obvious one of allowing the roots of plants to 

 get well down, is its aptitude for equalising the ' 

 supplies of moisture. There subsists no sympathy ^ 

 between the surface and a hard subsoil. If the 

 former is drenched with rain the latter refuses to 

 have any thing to do with it, and if the former is 

 parched the latter will yield none of its own mois- 

 ture; again, if the subsoil be pure gravel it readily 

 takes in the superabundant waters, but it soon 

 squanders them, and then has nothing to give back 

 to the surface in its greatest thirst. But when 

 you acquire a sufficient depth of soil you have a 

 large quantity of homogeneous matter which acts 

 sympathetically throughout, and is all nearly alike 

 wet, or alike dry, and consequently not so liable to 

 suffer injury by the too lotag continuance of rain or 

 drought. This improvement, then, as it renders 



