LECTURES AND ESSAYS READ AT INSTITUTES, 105 



tile, 16.4 acres, etc. It slionld always be borne in mind that the capacity of 

 tiles increases as the square of their diameter. Thus a 6-inch tile will carry 

 four times as much water as a 3-inch tile. It really increases a little faster 

 than that, because of less friction, for a given volume of water in the larger 

 tiles. 



The best tiles are round. All should be hard burned. Kound tiles can be 

 laid with better joints, as they can be turned in any position, and when the 

 ditch is properly scooped out with a round schoop, there is no difficulty in 

 keeping them in place. All drainage engineers, so far as I know, recommend 

 round tiles. Joints may be covered with turf — grass side next the tiles — 

 gravel, tan-bark, or bands of tarred paper.' 



The cost of drains will vary with the cost of tiles and price of labor, so will 

 be quite different in different sections. Counting labor at $1.00 per day, and 

 tiles at $10.00 per 1000, Mr. French, the author of a standard work on drain- 

 age, says that a tile drain four feet deep can be made for 50 cents per rod. 

 That estimate is too low, both for tiles and labor, to be strictly accurate in 

 this section. 



Most tile drains are made shallower than is recommended by those who 

 have given the subject a thorough study. They should at least be placed 

 below frost, and as the object is to lower the water table in the ground, four 

 feet is generally considered tiie best average depth. This, of course, will be 

 varied somewhat with the comparative cost of labor and tiles, and the kind of 

 outlet that can be secured. If tiles are cheap and labor dear they might be 

 placed a little shallower. It should be remembered that it costs about as 

 much to dig the last foot of a four foot ditch as it does to dig the other three. 



If the system contains many branches, it will be found convenient in caring 

 for the drains, and also lessen the liability of their becoming clogged, to build 

 a few silt basins. These should be built at the junctions of the laterals with 

 the mains, especially if the fall is much less in the mains. Several laterals 

 may flow into one silt basin and have but one outlet. The outlet should be 

 3 to inches lower than the inflowing pipe, and the basin be 8 to 12 inches 

 deeper than the discharge pipe, to make room for the deposition of silt, which 

 may be removed from time to time. Though very long mains are not often 

 advisable, as few outlets as possible should be made, and these should be 

 strong and durable. The Agricultural College has built several such outlets 

 very cheaply. They consist merely of a small wall of stone, laid in mortar, 

 placed deep enough to prevent heaving by frost, and extending two or three 

 feet each side of the last tile, which is built firmly in the wall. If the drain 

 is of sufficient importance, an iron pipe may be substituted for the last tile. 

 Some kind of screen for the outlet is useful to prevent vermin from entering 

 the tile. Many ways of doing this will suggest themselves to a thoughtful 

 farmer. The outlet should always be several inches above the water in the 

 main channel. 



After the drains are completed in this thorough manner, the farmer should 

 have a permanent record of them in the form of a map. This should show 

 the location of each drain, the length, and the points where all the branches 

 unite with the mains, with reference to some permanent marks. The farmer 

 will be surprised to find how much help such a map is when he wishes to 

 refer to any drain or add a new one to the system. 



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