s in a vessel, might be tapped and the water
conveyed harmlessly in the covered drain to the nearest ditch or stream.
In the circumstances to which it is applicable, and in the hands of
skilful drainers, Elkington's plan, known as "sink-hole drainage," by
bringing into play the natural drainage furnished by porous strata, is
often eminently successful.

[Illustration: Draining Implements.]

During the subsequent thirty or forty years most of the draining that
took place was on this system, and an immense capital was expended in
such works with varying results. Things continued in this position until
about 1823, when James Smith of Deanston, having discovered anew those
principles of draining so long before indicated by Blith, proceeded to
exemplify them in his own practice, and to expound them to the public in
a way that speedily effected a complete revolution in the art of
draining, and marked an era in agricultural progress. Instead of
persisting in fruitless attempts to dry extensive areas by a few
dexterous cuts, he insisted on the necessity of providing every field
that needed draining at all with a complete system of parallel
underground channels, running in the line of the greatest slope of the
ground, and so near to each other that the whole rain falling at any
time upon the surface should sink down and be carried off by the drains.
A main receiving drain was to be carried along the lowest part of the
ground, with sub-drains in every subordinate hollow that the ground
presented. The distances between drains he showed must be regulated by
the greater or less retentiveness of the ground operated upon, and gave
10 to 40 ft. as the limits of their distance apart. The depth which he
prescribed for his parallel drains was 30 in., and these were to be
filled with 12 in. of stones small enough to pass through a 3-in.
ring--in short a new edition of Blith's drain. Josiah Parkes, engineer
to the Royal Agricultural Society, advocated a greater distance apart
for the drains, and, in order that the subterranean water might be
reached, a depth of at least 4 ft.

The cultivated lands of Britain being disposed in ridges which usually
lie in the line of greatest ascent, it became customary to form the
drains in each furrow, or in each alternate, or third or fourth one, as
the case might require, or views of economy dictate and hence the system
soon came to be popularly called "furrow draining." From the number and
arrangement