lified by
considerations which weigh with unequal force in different cases.

In laying out work, any skillful drainer will be guided, in deciding the
distance between the lines, by a judgment which has grown out of his
former experience; and which will enable him to adapt the work,
measurably, to the requirements of the particular soil under
consideration; but he would probably find it impossible to so state the
reasons for his decision, that they would be of any general value to
others.

Probably it will be a long time before rules on this subject, based on
well sustained _theory_, can be laid down with distinctness, and, in the
mean time, we must be guided by the results of practice, and must confine
ourselves to a distance which repeated trial, in various soils, has proven
to be safe for all agricultural land. In the drainage of the Central Park,
after a mature consideration of all that had been published on the
subject, and of a considerable previous observation and experience, it was
decided to adopt a general depth of four feet, and to adhere as closely as
possible to a uniform distance of forty feet. No instance was known of a
failure to produce good results by draining at that distance, and several
cases were recalled where drains at fifty and sixty feet had proved so
inefficient that intermediate lines became necessary. After from seven to
ten years' trial, the Central Park drainage, by its results, has shown
that,--although some of the land is of a very retentive character,--this
distance is not too great; and it is adopted here for recommendation to
all who have no especial reason for supposing that greater distances will
be fully effective in their more porous soils.

As has been before stated, drains at that distance, (or at any distance,)
will not remove all of the water of saturation from heavy clays so rapidly
as from more porous soil; but, although, in some cases, the drainage may
be insufficient during the first year, and not absolutely perfect during
the second and third years, the increased porosity which drainage causes,
(as the summer droughts make fissures in the earth, as decayed roots and
other organic deposits make these fissures permanent, and as chemical
action in the aerated soil changes its character,) will finally bring clay
soils to as perfect a condition as they are capable of attaining, and will
invariably render them excellent for cultivation.

*The Direction of the Laterals* should