OPERATIONS OF DRAINING. 99 



hacked or perforated with the spade. The earth taken 

 from the trenches should be removed from their borders, 

 and either spread over the surface, or, if peaty, taken to 

 the compost-heap, or to higher grounds, so as to leave a 

 shght inclination, on each side, for the surface-waters to 

 pass into the drain. 



2. Draining the soil — of waters reposing upon the 

 subsoil. The soil, if the subsoil is porous, or a consid- 

 erable inclination exists in its position, may be freed from 

 surface-water by ridging. The surplus water, in these 

 cases, either settles down through the subsoil, or passes 

 off through the furrows between the ridges or upon the 

 inclined subsoil. But where the surface is nearly level, 

 and the subsoil tenacious, under-drains must be resorted 

 to, into which the water may settle and be conducted off, 

 before it injures the crops or texture of the soil. 



Under-drains, in cases to which we now have refer- 

 ence, need be but two to three feet deep, so that the ma- 

 terial of which they are constituted shall not be liable to 

 be disturbed by the tread of cattle, or the operations of 

 the plough. Some fifteen or twenty inches of these may 

 be economically sunk by the plough. The instruments 

 for completing them, are the common spade and shovel, 

 for throwing out the loose substances, and a pick or mat- 

 tock for raising the stones and breaking the earth where 

 hard. The sides may be nearly perpendicular, and the 

 ditch be no broader than is merely convenient to work in. 

 The workmen should commence at the lower, and work 

 up to the higher ground ; and so much descent should 

 not be given as to render the bottom and sides liable to 

 be worn away by a strong current of water. 



The materials to be used for forming the drains, may 

 be stones, tiles, or other hard substances. In drains where 

 considerable water is expected to flow, it is advisable to 

 form a conduit at the bottom, of four to ten inches square. 

 Where stones are to be employed, either as a covering 

 to the conduit, or as a drain of themselves, they should 

 be broken to so small a size, that moles or ground-mice 

 cannot penetrate and find a shelter among them ; for if 

 they can they will ; and by opening apertures to the sur- 



