HORSE-SHOE DRAIN. 117 



be washed in would be carried off. (B) is a square 

 of turf, old hay, coarse gravel, tan, or sawdust 

 placed over the stones to filter the water as it passes 

 to the drain; (C) is the position of the rubble, or 

 small stones ; and (D) represents another layer like 

 (B). The great objection to this drain is, that 

 workmen, unless very careful, will lay the stones 

 forming the triangle irregularly, so that one will 

 act as an obstruction to the other, and thus cause a 

 deposit of sediment. Boards are greatly to be pre- 

 ferred on this account, especially if planed upon 

 the inside, as they diminish the friction and prevent 

 obstructions. 



Is tile-pipe superficial 1 It is, unless baked hard, 

 when it becomes the most durable and perfect 

 drain. But, as there are many different ways of 

 constructing them, it is necessary that we should be 

 more explicit. 



The horse-shoe tile is not the most perfect, al- 

 though in many parts of our country it has been 

 used to a considerable extent ; yet we are assured 

 that it is not the most desirable. Being open at 

 the bottom, the earth often becomes pushed up in 

 the interior, and partially or wholly stops the flow. 

 In some instances, where obstructions have occurred, 

 the drain has been opened and the pipe found com- 

 pletely filled. Sometimes it is laid upoi, a sole, or 

 a board ; but it is then open to the same objection 

 as was the stone drain with the flat side down, — 



