Spade and hoe.
In digging the trenches it is not necessary (except in very stony ground) to dig out a place wide enough for a man to stand in, as there are tools made expressly for the purpose, by which a trench may be dug six or seven inches wide, and to any required depth. One set of these implements consists of a long narrow spade and a hoe to correspond, such as are represented in the accompanying figure.
With these tools, and a long light crowbar, for hard soils, trenches may be dug much more cheaply than with the common spade and pickaxe. Where there are large boulders in the soil, these draining tools may dig under them so that they will not have to be removed.
When the trenches are dug to a sufficient depth, the bottoms must be made perfectly smooth, with the required descent (from six inches to a few feet in one hundred feet). Then the tiles may be laid in, so that their ends will correspond, be packed down, and the trenches filled up. Such a drain, if properly constructed, may last for ages. Unlike the stone drain, it is not liable to be frequented by rats, nor choked up by the soil working into it.
The position of the tile may be best represented by a figure, also the mode of constructing stone drains.
Why are small stones better than large stones in the construction of drains?
On what must the depth of under-drains depend?
It will be seen that the tile drain is made with much less labor than the stone drain, as it requires less digging, while the breaking up of the stone for the stone drain will be nearly, or quite as expensive as the tiles. Drains made with large stones are not nearly so good as with small ones, because they are more liable to be choked up by animals working in them.[AK]
Fig. 6.
