CAUTION REQUIRED IN DRAINAGE. 335 



The same purpose is answered, but less effectively, by 

 the mole-plough, which is an implement framed so as to 

 make a small conduit beneath the soil, by means of an 

 iron-pointed cone or share. It is best adapted to strong 

 clay lands, for in other soils the conduit thus formed is 

 almost immediately obliterated. 



Although a certain degree of success attends every 

 attempt at drainage, yet the cost is so great that no one 

 will rashly venture upon it without real necessity for so 

 doing. A farmer will be very careful how he sinks 

 valuable capital in injudicious draining, thereby crip- 

 pling his resources, and preventing him from carrying 

 on other necessary improvements which equally demand 

 his attention. There can be no doubt that a vast extent 

 of arable land throughout Great Britain and Ireland is 

 seriously injured by the imperfect escape of water, and 

 its fertility greatly diminished thereby ; yet sound judg- 

 ment is required in applying the remedy ; for many per- 

 sons competent to make a good drain may fail of full 

 success from not making it in the right place, and may 

 therefore waste money and time in the attempt. Some 

 knowledge of the structure of the upper portion of the 

 earth's crust must be acquired ; and also a practical 

 acquaintance with those circumstances in which deep 

 draining is required, and of those in which a different 

 management may be adopted. 



When draining operations are actually going on, the 

 business should be constantly superintended by a person 

 who well understands it. Without this, half the benefit 

 will be lost through the carelessness of the workmen, 

 who will naturally take the methods that seem to give 

 the least present trouble. The spade work will be 

 roughly done, the tiles carelessly laid down, and per- 

 haps the drain left open for a long time in wet weather 

 or frosts, at the risk of the giving way of the banks, 

 and the bursting in pieces of the tiles. All this is 

 easily prevented by the presence of an active superin- 

 tendent. 



