(56 TILE DRAINAGE. 



the drain. The water should always find the tiles by soaking 

 directly down into the soil wherever it falls, and then, under 

 the force of gravity, or hydrostatic pressure, soaking slowly 

 sidewise under ground through the pores of the soil, and 

 entering the tiles at their joints at the sides and bottom, not 

 the top. Such is the teaching of all the authorities on 

 drainage. Such is the way the water and tiles actually 

 behave on my farm, according to my careful observations. 



If the theory of my critic were correct it should be carried 

 to its full extent, and the drains run square across the slope. 

 Then the water could run straight down the slope until it 

 came directly above each drain, and at <>nce sink straight 

 down into it. This, I repeat, is exactly what we do not want. 

 One chief object of tile drainage is to prevent surf ace- wash, 

 and to prevent the water's flowing along the surface at all ; 

 to open the large pores of the soil straight down, nearly to 

 the level of the tiles, and keep them open so that, when rain 

 falls or snow melts it may go down these open pores and 

 work off as it descends gradually sidewise in the soil to the 

 tiles; this prevents surface-wash, filters the water, and leaves 

 all plant-food in the soil where the roots can get it. 



Fi0. 18.- Cross-section of tiles properly laid; /. e., straight down the 

 slope, so that the siirface at right angles to the drains shall be a level 

 line, and the water seek the drains equally from both sides, and the 

 tiles drain the whole ground to uniform depth. 



Fig. 18 roughly represents the way water seeks tile drains 

 where they are properly laid that is, straight down the 

 slope. It gives a cross-section of two tile drains to one who 



