tch-water is essential to success. The wettest spot in a swamp is
frequently, just at its edge, because there the surface-water is
received, and because there too, the water that has come down on an
impervious subsoil stratum, finds vent. It is in vain to attempt to lay
dry a swamp, by drains, however deep, through its centre. The water has
done its mischief, before it reaches the centre. It should be
intercepted, before it has entered the tract, to be reclaimed.

This drain must be deep, and therefore, must be wide and sloping, so
that it may be kept open; and it should be curved round, following the
line of the upland to the outlet. Often it has been found, in England,
that a single drain, six or eight feet deep, has completely drained a
tract of twenty or thirty acres, by cutting off all the sources of the
supply of water, except that from the clouds. This kind of land is very
porous and permeable, and readily parts with its water, and is easily
drained; so that the frequent drains necessary on uplands, are often
quite unnecessary. Many instances are given, of the effect of single
deep drains through such tracts, in lowering the water in wells, or
entirely drying them, at considerable distances from the field of
operation.

When the surface-water and shallow springs have thus been cut off, the
drainer will soon be able to determine, whether he has effected a cure
of his dropsical patient. Often it will be found, that deep seated
springs burst up in the middle of these low tracts, furnishing good and
pure water for use. These, being supplied by high and distant fountains,
run under our deepest drains, and find vent through some fracture of the
subsoil. They diffuse their ice-cold water through the soil, and prevent
the growth of all valuable vegetation. To these, we must apply
Elkington's system, and hit them _right in the eye_! by running a deep
drain from some side or central drain, straight to them, and drawing off
the water low enough beneath the surface to prevent injury. A small
covered drain with two-inch pipes, will usually be sufficient to afford
an outlet to any such spring.

When we have thus disposed of the water from the surface-flow, the
shallow springs and the deep springs, and given vent to the water
accumulated and ponded in the low places, we have then accomplished all
that is peculiar to this kind of drainage. We have still the water from
the clouds, which is twice as much as will evaporate from a