DEPTH OF DRAINS. 113 



stopped in their operation by the roots oi fruit trees, 

 still it is very desirable to place them so frequently 

 that the water will pass off speedily and leave the 

 pipes dry. 



4. The depth at which drains should he 2)laced. The 

 first argument that we shall use for placing them 

 deep is that they may be out of reach of the subsoil 

 plough, or the spade of the trencher. The necessity 

 for deep cultivation, in preparing the ground for the 

 orchard, is considered in the chapter devoted to pul- 

 verization ; suffice it now to say, that in trenching 

 three feet in depth, the spade will often be plunged 

 a few inches further, and that one blow might break 

 a tile, and result in the stoppage of the whole 

 system.^ Then it must be remembered that as the 

 air penetrates more into drained than undrained 

 soils, they will freeze deeper. If we place the drain 

 at four feet deep, in a retentive soil, we shall often 

 find that we have not more than two or three feet 

 of dry earth, on account of capillary attraction. 



.The greater sphere which it gives to the roots of 

 plants for their supply of food, is of itself a suffi- 

 cient argument for deep draining. Of equal force 

 is the fact, that it wards off the evil effects of 

 drought. It may seem to some an anomaly, that to 

 drain the surplus water from land would make it 

 less likely to suffer from the want of it ; and yet 

 such is the truth. On an undrained soil the roots of 



1 See mode of detecting obstructions. 



10* 



