444 Irrigation and Drainage 



when well done, was permanent and effective. Square 

 blocks of peat have been grooved on one face and 

 two of these placed together to form a tile, thus 

 making a drain of another kind. Each of these 

 methods of securing underdrainage involved much 

 labor ; gave channels in which the water flowed with 

 great resistance ; clogged easily, and while beneficial 

 results invariably followed their use, they were neither 

 wholly satisfactory nor permanent. 



When the manufacture of tiles from burned clay 

 was begun, various shapes were adopted and abandoned 

 for the present cylindrical type, which when well 

 made and laid, has been found entirely satisfactory 

 for the construction of closed drains. 



In more recent years an effort has been made to 

 build a continuous line of tiles in the bottom of the 

 ditch after it is dug and graded, using a concrete 

 made from the best hydraulic cement, lime and sand. 

 The mortar, when made, is fed through a simple 

 machine, which determines the size and shape of the 

 tile, making it continuous, cylindrical and smooth on 

 the inside. A trowel is used to cut the tile through 

 to near the lower side with sufficient frequency to 

 permit the necessary percolation from the soil, thus 

 securing a drain with all joints perfect. The system, 

 however, has not been sufficiently long in use to 

 enable one to say how meritorious it is. 



Open surface drains, where they are permanent 

 improvements, should, if possible, be made wide and 

 with sides so gently sloping as not to be washed, and, 

 if possible, so as to be grassed over and driven through 



