he level of the water inside. It is well to place
the mouth of the trunk nearly as low as ordinary low-water mark. This will
frequently render it necessary to carry a covered drain, of wood or brick,
through the mud, out as far as the tide usually recedes,--connected with
the valve gate at the outlet of the trunk, by a covered box which will
keep rubbish from obstructing it, or interfering with its action.

_When the outlet of the land-drains is below low-water mark_, it is of
course necessary to pump out the drainage water. This is done by steam or
by wind, the latter being economical only for small tracts which will not
bear the cost of a steam pump. Formerly, this work was done entirely by
windmills, but these afford only an uncertain power, and often cause the
entire loss of crops which are ready for the harvest, by obstinately
refusing to work for days after a heavy rain has deluged the land. In
grass land they are tolerably reliable, and on _small_ tracts in
cultivation, it is easy, by having a good proportion of open ditches, to
afford storage room sufficient for general security; but in the reclaiming
of large areas, (and it is with these that the work is most economical,)
the steam pump may be regarded as indispensable. It is fast superseding
the windmills which, a few years ago, were the sole dependence in Holland
and on the English Fens. The magnitude of the pumping machinery on which
the agriculture of a large part of Holland depends, is astonishing.

There are such immense areas of salt marsh in the United States which may
be tolerably drained by the use of simple valve gates, discharging above
low-water mark, that it is not very important to consider the question of
pumping, except in cases where owners of small tracts, from which a
sufficient tidal outlet could not be secured, (without the concurrence of
adjoining proprietors who might refuse to unite in making the
improvement,) may find it advisable to erect small pumps for their own
use. In such cases, it would generally be most economical to use
wind-power, especially if an accessory steam pump be provided for
occasional use, in emergency. Certainly, the tidal drainage should first
be resorted to, for when the land has once been brought into cultivation,
the propriety of introducing steam pumps will become more apparent, and
the outlay will be made with more confidence of profitable return, and, in
all cases, the tidal outlet should be depended on for t