ON DUAINING. 



401 



where the water easily escapes. Nos. 5, 6, 7, 8, 9, 10, 

 11, wet ground with a retentive subsoil, preventing the 

 water from escaping, whereby it accumulates on the sur- 

 face. 



The operation of surface draining is generally perform- 

 ed with the spade, the usual dimensions of the drains being 

 about 18 inches wide at the top, 9 inches at the bottom, 

 and about 14 inches deep ; when these d_i*ains are numer- 

 ous, the work is tedious and expensive. In many cases this 

 operation might be done by the plough, at much less ex« 

 pense than by the spade, and at a season of the year when 

 no other field operations are going on. A very strong 

 plough must be used, drawn by four horses, to draw a 

 furrow down hill: where the declivity is not too great, 

 the plough should return close by the back of the furrow 

 thrown up, thus cutting the solid ground out ; or it might 

 return in the same track, throwing a furrow over the other 

 side: but when the declivity is very great, it will be prefer- 

 able to draw all the furrows down hill, the plough being 

 brought up empty ; the expense is nearly the same by 

 either method, and the particular circumstances of the 

 case will best determine which of them should be used. 

 Wliere the declivity is considerable, this method will an- 

 swer tolerably well ; but if the gi'ound be level small 

 drains soon fill up. 



When a large extent of ground is to be planted up, and 

 when the decli\'ity is small, it will be necessary to cut 

 all the drains with the spade : these should, on wet 



