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of stagnant under-ground water are to be drained off, under- 
drains are most efficient and practicable. 
The building of a permanent drainage system requires careful 
study of the local conditions, the lay of the land, amount of water 
to be removed, nature of the soil, etc. It is perhaps hardly neces- 
sary to describe the building of the ordinary open drain ditches, 
as this is too well known to all connected with agriculture. A 
few words on under-drains might, however, be of interest. 
Often a layer of heavy impervious clay or other material will 
prevent the water in the surface soil from penetrating the sub- 
soil and by opening this blanket or hard pan at certain intervals 
communication between the surface soil and the lower strata is 
/vy. I Fig £ 
established, allowing the excess water in the surface soil to drain 
off ; see figures 1 and 2. 
Under-drains are built in the same manner as the open drain 
ditches, the bottom of the ditch is thereupon filled with coarse 
stones, loosely packed for about 12 to 15 inches over which a 
layer of small pebbles is placed ; the latter is covered with grass- 
sods, straw or similar material and then the whole ditch is filled 
with earth again. Care must be taken that the original surface 
soil is placed on top again. 
Excellent results have been obtained in the United States and 
Europe with drain tiles. Porous tiles of baked clay are used 
and laid carefuly at a depth to suit conditions and according to 
the natural lay of the land. These tile drains are laid parallel 
to each other as much as possible, and in the direction of the 
