Convey the pipes by wagon or otherwise, as is convenient, to the side of the ditch where the soil lies, and where there is least earth, and lay them close to the edge of the ditch, end to end the whole way, discarding all imperfect pieces. If it is designed to use gravel, turf, or other covering for the pipes, lay it also in heaps along the trench. Then place the first pipe at the upper end of the ditch, with a brick or stone against its upper end, to exclude earth. We have heretofore used sole-tiles, with flat bottoms, and have found that a thin chip of wood, not an eighth of an inch thick, and four by two inches in size, such as may be found at shoe shops in New England, assists very much in securing an even bearing for the tiles. It is placed so that the ends of two tiles rest on it, and serves to keep them in line till secured by the earth. A man walking backward in the ditch, takes the tiles from the bank, carefully adjusting them in line and so as to make good joints, and he can lay half a mile or more in a day, if the bottom is well graded. Another should follow on the bank, throwing in a shovel full of gravel or tan, if either is used, upon the joint.
If turf is to be used to secure the joint, pieces should be cut thin and narrow, and laid along the bank, and the man in the ditch must secure each joint as he proceeds. It will be found to cost twice the labor, at least, to use turf, as it is to use gravel or tan, if they are at hand.
If the soil be clay, we do not believe it is best to return it directly upon the tiles, because it is liable to puddle and stop the joint, and then to crack and admit silt at the joint, while gravel is not thus affected. We prefer to place the top soil of clay land, next the pipes, rather than the clay in the condition in which it is usually found.
As to small stones above the pipes, we should decidedly object to them. They are unnecessary to the operation of the drain, and they allow the water to come in, in currents, on to the top of the pipes, in heavy storms or showers, and so endanger their security. The practice of placing stones above the tiles is abandoned by all scientific drainers.
We have, in England, seen straw placed over the joints of pipes, but it seems an inconvenient and insecure practice. Long straw cannot be well placed in such narrow openings, and it is likely to sustain the earth enough, so that when thrown in, it will not settle equally around the pipes; whereas a shovelfull of gravel or other earth sifted in carefully, will at once fasten them in place.
Having laid and partially covered the first or upper drain, proceed with the next in the same way, laying and securing the main or sub-main, at the same time, to each intersection, thus carrying the work from the highest point down towards the outlet. After sufficient earth has been thrown in to make the work safe against accidents by rain, or caving in of earth, the filling may be completed at leisure. Mr. Johnston, of Geneva, uses for this purpose a plow, having a double-tree nine and a half feet long, to enable a horse to go on each side of the ditch.
We suggest that a side-hill plow might well enough be used with horses tandem, or with oxen and cart wheels and draughts.
The filling, however, will be found a small matter, compared with the digging. In laying pipes in narrow trenches, a tool called a pipe-layer is sometimes used, a cut of which, showing its mode of use, may be found in another place.
In filling drains where the soil is partly clay, and partly sand or gravel, we recommend that the clay be placed in the upper part of the drain, so as to prevent water from passing directly down upon the pipes, by which they are frequently displaced as soon as laid.
If the work is completed in Autumn, it is well to turn two or three furrows from each side on to the drains, so as to raise the surface there, and prevent water from cutting out the ditch, or standing above it. If the land is plowed in Autumn, it is best to back-furrow on to the drains, leaving dead furrows half way between them, the first season.