land-surface, to provide for. We assume that this cannot pass directly
down by percolation, because the subsoil is already saturated; and
therefore, even if all the other sources of wetness are cut off, we
shall still have a tract of land too wet for wheat and corn. If the
swamp be very small, these main ditches may sufficiently drain it; but
if it be extensive, they probably will not. We have seen that we have
some eighteen or twenty inches of water to be disposed of by drainage;
so much that evaporation cannot remove consistently with good
cultivation; and, although this amount might, in a very deep peaty soil,
percolate to a great distance laterally, to find a drain, yet in shallow
soil resting on a retentive subsoil, drains might be necessary at
distances similar to those adopted on wet upland fields. To this part of
the operation, we should, therefore, apply the ordinary principles of
drainage, putting in covered drains with tiles, if possible, at four
feet depth or more, ordinarily, and at distances of from forty to sixty
feet, although four-foot drains at even one hundred feet distance, in
peat and black mud, might often be found sufficient.

Through the kindness of Edmund Ruffin, Esq., of Virginia, we have been
furnished with three elaborate and valuable essays, on the drainage and
treatment of flat and wet lands in lower Virginia and North Carolina,
published in the Transactions of the Virginia State Agricultural
Society, for 1857. The principal feature of his system is based upon his
correct knowledge of the geological formation of that district; of the
fact in particular, that, underlying the whole of that low country,
there is a bed of pure sand lying nearly level, and filled with water,
which may be drawn down by a few large deep drains, thus relieving the
surface-soil of surplus water, by comprehensive but simple means.

We have before referred to Mr. Ruffin as the publisher, more than twenty
years ago, of "Elkington's Theory and Practice of Draining, &c., by
Johnstone;" and we find in his recent essays, evidence of how thoroughly
practical he has made the system of Elkington in his own State. Indeed,
we know of no other American writer who records any instance of marked
success in the use of Elkington's peculiar idea of releasing pent up
waters by boring. Mr. Ruffin, however, has applied, with great success,
this principle of operation, to the saturated sand-beds which underlie
the tracts of low land in