d, we all know of fields
drained only with stone drains two feet deep, that have been reclaimed
from wild grasses and rushes into excellent mowing fields. In England
and in Scotland, as we have seen, thousands of miles of shallow drains
were laid, and were for years quite satisfactory. These facts speak
loudly in favor of drainage in general. The fact that shoal drains
produce results so striking, is a stumbling-block in the progress of a
more thorough system. It may seem like presumption to say to those to
whom we are so much indebted for their public spirit, as well as private
enterprise, that they have not drained deep enough for the greatest
advantage in the end. It would seem that they should know their own
farms and their own results better than others. We propose to state,
with all fairness, the results of their experiments, and to detract
nothing from the credit which is due to the pioneers in a great work.

We cannot, however, against the overwhelming weight of authority, and
against the reasons for deeper drainage, which, to us, seem so
satisfactory, conclude, that even three feet is, in general, deep enough
for under-drains. Three-foot drains will produce striking results on
almost any wet lands, but four-foot drains will be more secure and
durable, will give wider feeding-grounds to the roots, better filter the
percolating water, warm and dry the land earlier in Spring, furnish a
larger reservoir for heavy rains, and, indeed, more effectually perform
every office of drains.

In reviewing our somewhat minute discussion of this essential point--the
proper depth of drains--certain propositions may be laid down with
considerable assurance.

TILES MUST BE LAID BELOW THE REACH OF THE SUBSOIL PLOW.

Let no man imagine that he shall never use the subsoil plow; for so
surely as he has become already so much alive to improvement, as to
thorough-drain, so surely will he next complete the work thus begun, by
subsoiling his land.

The subsoil plow follows in the furrow of another plow, and if the
forward plow turn a furrow one foot deep, the subsoil may be run two
feet more, making three feet in all. Ordinarily, the subsoil plow is run
only to the depth of 18 or 20 inches; but if the intention were to run
it no deeper than that, it would be liable to dip much deeper
occasionally, as it came suddenly upon the soft places above the drains.
The tiles should lie far enough below the deepest path of the subsoil
plow,