134 



UNDERDRAINIXG AND DEEP TILLAGE. 



on or near the surface. In fact, such jBelds must be thoroughly 

 cleared from them before thej can be easily cultivated. "When this 

 is the case, stones may be employed to advantage, although they 

 require a much -wider trench than tiles, of which we shall soon 

 speak. Stones should be so laid as to form as perfect a conduit as 

 may be. 



Fig. 1. 



a 



c 

 d 



