he bottom be cut out
just wide enough to admit the pipes and no more. Pipes, when accurately
fitted in, are much less liable to derangement than when laid in the
bottom of a trench several times their width, into which a mass of loose
earth must necessarily be returned. This is easily effected in the case
of soils tolerably free from stones by the use of draining spades and
the tile-hook which are represented in the accompanying cut. The
tile-hook is an implement by means of which the pipes may be lowered
from the edge of the trench and laid at the bottom. An implement,
sometimes propelled by steam, known as the draining plough, can be used
for opening the trenches. Draining can be carried on at all seasons, but
is usually best done in autumn or summer. A thoroughly trustworthy and
experienced workman should be selected to lay the pipes, with
instructions to set no pipes until he is satisfied that the depth of the
drains and level of the bottoms are correct. The expense of
tile-drainage may vary from about L2:10s. per acre on loose soils to L10
an acre on the most tenacious soils, the rate of wages and the cost of
the pipes, the depth of the trenches and the ease with which they can be
dug, all influencing the cost of the process.

Drainage is not a modern discovery. The Romans were careful to keep
their arable lands dry by means of open trenches or covered drains
filled with stones or twigs. It is at least several centuries since
covered channels of various kinds were used by British husbandmen for
drying their land. Walter Blith (see AGRICULTURE) about the middle of
the 17th century wrote of the improvement which might be effected in
barren land by freeing it from the excess of stagnant water on or near
the surface by means of channels filled with faggots or stones, but his
principles, never generally adopted, were ultimately forgotten. In the
latter half of the 18th century, Joseph Elkington, a Warwickshire
farmer, discovered a plan of laying dry sloping ground that is drowned
by the outbursting of springs. When the higher-lying portion of such
land is porous, rain falling upon it sinks down until it is arrested by
clay or other impervious matter, which causes it again to issue at the
surface and wet the lower-lying ground. Elkington showed that by cutting
a deep drain through the clay, aided when necessary by wells or auger
holes, the subjacent bed of sand or gravel in which a body of water is
pent up by the clay, a