Oil the Drainage of Land. 



275 



Soils of various kinds are in many cases infested with surface 

 springs, which may frequently be got rid of with comparative ease 

 by open drains, which lay the land tolerably dry wherever there 

 is sufficient declivity to carry off the water ; although, if these be 

 cut on pasture-land, they are subject to this objection, that, if 

 sheep be fed upon it, they sometimes render the fat stock liable 

 to the accident of being cast. If, however, those springs be lower 

 down, and found at different distances in alternate strata of sand 

 and clay, or gravel, their depth should be ascertained by boring ; 

 as the land can never be laid dry until perforated to the bed of 

 impervious subsoil upon which those strata rest, and upon which 

 covered drains must be sunk for the complete escape of the 

 superabundant moisture. It should also be borne in mind, that, 

 although open and covered drains m.ay have partly similar effects, 

 they are yet essentially different in execution, and should never 

 be used together in the same operation ; for if the surface water 

 be allowed an open passage into the covered drains, the sand and 

 earth which it will carry into their channels will be apt to choke 

 them up. 



Heavy clays also, like those, for instance, in the wealds of Kent 

 and Sussex, or any land retentive of water, and lying upon a dead 

 level, can never be rendered efficiently productive without the 

 most thorough under-ground drainage ; for, the water being up- 

 held upon the surface during the winter, the ground must be 

 ridged up at a great expense of toil and wages for the purpose of 

 exposing it to the sun and air ; yet still vegetation flags until an 

 advanced period of summer sunshine evaporates the injurious 

 humidity occasioned by the falls of snow and rain. In this state, 

 indeed, may be found some of the richest land in the kingdom, 

 consisting of alluvial layers of absorbent earth over a substratum 

 of adhesive clay, with a surface of little or no declination, which, 

 thus retaining the superfluous moisture, retards the progress of 

 vegetation ; added to which, if the land be in grass, it will be 

 materially injured by the poaching of cattle pastured upon it in 

 wet weather ; and, if sheep be put upon it in autumn, it will go 

 far to rot them. 



Hence the plants become sickly, the harvests are generally late 

 as well as precarious, and the crops not unfrequently deficient in 



more thoroughly it is drained the greater effect will bone-dust have upon it 

 as a manure." — P. 176. 



" The perceptible dampness in undrained soils dissolves the soluble por- 

 tion of farm-yard manure, which, by its gravity, descends beyond the root- 

 lets of young plants, whilst the strawy portion remains undecomposed for a 

 length of time, which may account for the invariable languid vegetation of 

 plants, while young, in undrained land." — P. 173. 



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