Instead of the whole trench forming a gradually tapering
wedge, the upper portion of the shoulder-drain has the sides of the
trench nearly perpendicular, and of considerable width, the last spit
only being taken out with a narrow, tapering spade, by which means a
shoulder is left on either side, from which it takes its name. After the
trench has been finished, the first spit, having the grassy side
undermost as in the former case, is placed in the trench, and pushed
down till it rests upon the shoulders already mentioned; so that a
narrow wedge-shaped channel is again left for the water, as shown in
Fig. 15.

[Illustration: Fig. 14.--WEDGE-DRAIN.]

[Illustration: Fig. 15.--SHOULDER-DRAIN.]

These drains may be formed in almost any kind of land which is not a
loose gravel or sand. They are a very cheap kind of drain; for neither
the cost of cutting nor filling in, much exceeds that of the ordinary
tile drain, while the expense of tiles or other materials is altogether
saved. Still, such drains cannot be recommended, for they are very
liable to injury, and, even under the most favorable circumstances, can
only last a very limited time.

LARCH TUBES.

These have been used in Scotland, in mossy or swampy soils, it is said,
with economy and good results. The tube represented below presents a
square of 4 inches outside, with a clear water-way of 2 inches. Any
other durable wood will, of course, answer the same purpose. The tube is
pierced with holes to admit the water. In wet meadows, these tubes laid
deep would be durable and efficient, and far more reliable than brush or
even stones, because they may be better protected from the admission of
sand and the ruinous working of vermin. Their economy depends upon the
price of the wood and the cost of tiles--which are far better if they
can be reasonably obtained.

[Illustration: Fig. 16.--LARCH TUBE-DRAIN.]

Near Washington, D. C., we know of drainage tolerably well performed by
the use of common fence-rails. A trench is opened about three inches
wider at bottom than two rails. Two rails are then laid in the bottom,
leaving a space of two or three inches between them. A third rail is
then laid on for a cover, and the whole carefully covered with turf or
straw, and then filled up with earth. Poles of any kind may be used
instead of rails, if more convenient.

In clay, these drains would be efficient and durable; in sand, they
would be likely to be filled up and become