72 



PIPE TILES. 



Fi?. e. 



The portion of earth next the drain first dries; as it 

 shrinks on drying, little cracks begin to radiate in 

 every direction, and to spread until at last they have 

 penetrated through the whole mass of soil that is 

 within the influence of the drain, making it all, after 

 a season or two, light, mellow, and wholesome for 

 plants. 



The appearance of tile drains in the earth is shown 

 by fig. 8, representing a cross 

 section. They form a connected 

 tube through which water runs 

 with great freedom, even if the 

 fall is very slight. When care- 

 fully laid, they will discharge 

 water where the fall is not more 

 than two or three inches per 

 mile. If buried at a good depth, 

 they can scarcely be broken ; 

 and if well baked, are not liable to moulder away. 

 There seems no reason why well made drains of this 

 kind should not last for a century. The pipe tiles are 

 used of from 1 to 1^ inches diameter of bore for the 

 smaller drains, and for the larger up as high as 4 or 5 

 inches. They are all made in pieces of from 12 to 14 

 inches in length. An inch pipe will discharge an 

 immense quantity of water, and is quite sufl^cient for 

 most situations. These small drains should not or- 

 dinarily be carried more than 4 or 500 feet before they 

 F"g- 9- pass into a larger one, running across their 

 ends. Where a very great quantity of water 

 is to be discharged, two large-sized horse- 

 shoe tiles are often employed, one inverted 

 against the other as in fig. 9. 

 Third, as to the direction in which the drains should 

 run. The old fashion was to carry them around the 

 slopes, so as to citt off the springs; but it is now found 

 most efficacious to run them straight doum, at regular 



