184 OULTIVAflON. 



they are very much more costly than tile drains, and 

 are not so permanent. 



TILE DKAINmO. 



The best under-drains are those made with tiles, 

 or burnt clay pipes. The first form of these used 

 was that called the liorse-slwe tile, which has the 

 form of an arch, leaving the unprotected ground for 

 the water to flow over ; this was superseded by the 

 round pipe, and the sole tile. 



""Experience in both public and private works in this 

 country, and the cumulative testimony of English and 

 French engineers, have demonstrated that the only 

 tile which it is economical to use, is the hest that can 

 be found, and that the best, — much the best, — thus 

 far invented, is the pipe, or round tile, mid collar ; 



Round Tile and Collax. 



and these are unhesitatingly recommended for use in 

 all cases. Round tiles of small sizes should not be laid 

 without collars, as the ability to use these constitutes 

 tlieir chief advantage; holding them perfectly in 

 place, preventing the rattUng in of loose dirt in la}'- 

 ing, and giving twice the space for the entrance of 

 water at the joints. A chief advantage of the 

 larger sizes is, that they may be laid on any side and 

 thus made to fit closely. The usual sizes of these 



