Main Drain of two or more Horse-shoe Tiles.
The combinations represented in the above figures, will furnish sufficient suggestions to enable any one to select or arrange such forms as may be deemed best suited to the case in hand. Where the largest obtainable tile is not large enough, two or more lines of pipes may be laid abreast.
POSITION OF THE MINOR DRAINS.
Assuming that it is desirable to run the small drains, as far as practicable, up and down the slope, the following directions, from the Cyclopedia of Agriculture, are given:
"There is a very simple mode of laying out these (the minor drains), which will apply to most cases, or, indeed, to all, although in some its application may be more difficult. The surface of each field must be regarded as being made up of one or more planes, as the case may be, for each of which the drains should be laid out separately. Level lines are to be set out, a little below the upper edge of each of these planes, and the drains must be then made to cross these lines at right angles. By this means, the drains will run in the line of the greatest slope, no matter how distorted the surface of the field may be."
Much is said, in the English books, about "furrows," and the "direction of the furrows," in connection with the laying out of drains. Much of the land in England, especially in moist places, was formerly laid up by repeated plowings, into ridges varying in breadth from ten to twenty feet, so as to throw off, readily, the water from the surface.
These ridges were sometimes so high, that two boys in opposite furrows, between the ridges, could not see each other. In draining lands thus ridged, it is found far more easy to cut the ditches in the furrows, rather than across or upon the ridges. After thorough-drainage, in most localities, these ridges and furrows are dispensed with. The fact is, probably, only important here, as explaining the constant reference by English writers to this mode of working the land.
Whether we shall drain "down the furrows," or "across the ridges," is not likely to be inquired of, by Americans.