128 THE MANSE GARDEN. 



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 cannot be 

 consumed, it adds depth to a thin soil, and communi- 

 cates 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 equalizing the sup- 

 plies of moisture. There subsists no sympathy be- 

 tween 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 moisture ; 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 homoge- 

 neous matter which acts sympathetically throughout, 

 and is all nearly alike wet or alike dry, and conse- 

 quently not so liable to suffer injury by the too long 

 continuance of rain or drought. This improvement, 

 then, as it renders the elements of nature more sub- 

 servient to the purposes of vegetation, is permanent, 

 and cannot wear out or lose its effect, as that of 

 manuring, at whatever expense, must certainly do. 



But though permanent in this respect, it is not 

 to be inferred that there is no further need of subse- 

 quent trenching. A repetition of this work, at any 

 future period, gives the great benefit of rest to that 

 part of the soil which has been exhausted by con- 

 tinual bearing. We are aware that some theorists 

 decry the notion of exhaustion, and contend that 



