Fig. 30 - POSITION OF WORKMAN AND USE OF FINISHING SCOOP.
Three persons are required to finish the bottom of the[pg 126] ditch; one to sight across the tops of the boning-rods, one to hold the plumb-rod at different points as the finishing progresses, and one in the ditch, (see Fig. 30,) provided with the finishing spade and scoop,—and, in hard ground, with a pick,—to cut down or fill up as the first man calls "too high," or, "too low." An inch or two of filling maybe beaten sufficiently hard with the back of the scoop, but if several inches should be required, it should be well rammed with the top of a pick, or other suitable instrument, as any subsequent settling would disarrange the fall.
Fig. 31 - SIGHTING BY THE BONING-RODS.
As the lateral drains are to be laid first, they should be the first graded, and as they are arranged to discharge into the tops of the mains, their water will still flow off, although the main ditches are not yet reduced to their final[pg 127] depth. After the laterals are laid and filled in, the main should be graded, commencing at the upper end; the tiles being laid and covered as fast as the bottom is made ready, so that it may not be disturbed by the water of which the main carries so much more than the laterals.
Tile-Laying.—Gisborne says: "It would be scarcely more absurd to set a common blacksmith to eye needles than to employ a common laborer to lay pipes and collars." The work comes under the head of skilled labor, and, while no very great exercise of judgment is required in its performance, the little that is required is imperatively necessary, and the details of the work should be deftly done. The whole previous outlay,—the survey and staking of the field, the purchase of the tiles, the digging and grading of the ditches—has been undertaken that we may make the conduit of earthenware pipes which is now to be laid, and the whole may be rendered useless by a want of care and completeness in the performance of this chief operation. This subject, (in connection with that of finishing the bottoms of the ditches,) is very clearly treated in Mr. Hoskyns' charming essay,[19] as follows:
"It was urged by Mr. Brunel, as a justification for more attention and expense in the laying of the rails of the Great Western, than had been ever thought of upon previously constructed lines, that all the embankments and cuttings, and earthworks and stations, and law and parliamentary expenses—in fact, the whole of the outlay encountered in the formation of a railway, had for its main and ultimate object a perfectly smooth and level line of rail; that to turn stingy at this point, just when you had arrived at the great ultimatum of the whole proceedings, viz: the iron wheel-track, was a sort of saving which evinced a want of true preception of the great object of all the labor that had preceded it. It[pg 128] may seem curious to our experiences, in these days, that such a doctrine could ever have needed to be enforced by argument; yet no one will deem it wonderful who has personally witnessed the unaccountable and ever new difficulty of getting proper attention paid to the leveling of the bottom of a drain, and the laying of the tiles in that continuous line, where one single depression or irregularity, by collecting the water at that spot, year after year, tends toward the eventual stoppage of the whole drain, through two distinct causes, the softening of the foundation underneath the sole, or tile flange, and the deposit of soil inside the tile from the water collected at the spot, and standing there after the rest had run off. Every depression, however slight, is constantly doing this mischief in every drain where the fall is but trifling; and if to the two consequences above mentioned, we may add the decomposition of the tile itself by the action of water long stagnant within it, we may deduce that every tile-drain laid with these imperfections in the finishing of the bottom, has a tendency toward obliteration, out of all reasonable proportion with that of a well-burnt tile laid on a perfectly even inclination, which, humanly speaking, may be called a permanent thing. An open ditch cut by the most skillful workman, in the summer, affords the best illustration of this underground mischief. Nothing can look smoother and more even than the bottom, until that uncompromising test of accurate levels, the water, makes its appearance: all on a sudden the whole scene is changed, the eye-accredited level vanishes as if some earthquake had taken place: here, there is a gravelly scour, along which the stream rushes in a thousand little angry-looking ripples; there, it hangs and looks as dull and heavy as if it had given up running at all, as a useless waste of energy; in another place, a few dead leaves or sticks, or a morsel of soil broken from the side, dams back the water for a[pg 129] considerable distance, occasioning a deposit of soil along the whole reach, greater in proportion to the quantity and the muddiness of the water detained. All this shows the paramount importance of perfect evenness in the bed on which the tiles are laid. The worst laid tile is the measure of the goodness and permanence of the whole drain, just as the weakest link of a chain is the measure of its strength."
The simple laying of the smaller sizes of pipes and collars in the lateral drains, is an easy matter. It requires care and precision in placing the collar equally under the end of each pipe, (having the joint at the middle of the collar,) in having the ends of the pipes actually touch each other within the collars, and in brushing away any loose dirt which may have fallen on the spot on which the collar is to rest. The connection of the laterals with the mains, the laying of the larger sizes of tiles so as to form a close joint, the wedging of these larger tiles firmly into their places, and the trimming which is necessary in going around sharp curves, and in putting in the shorter pieces which are needed to fill out the exact length of the drain, demand more skill and judgment than are often found in the common ditcher. Still, any clever workman, who has a careful habit, may easily be taught all that is necessary; and until he is thoroughly taught,—and not only knows how to do the work well, but, also, understands the importance of doing it well,—the proprietor should carefully watch the laying of every piece.
Never have tiles laid by the rod, but always by the day. "The more haste, the less speed," is a maxim which applies especially to tile-laying.