cut off some particular springs, or to assist
Nature in some ravine or basin, a deep drain here and there may be
expedient; but when any considerable surface is to be drained, there can
be no good work without a connected plan of operations.

Mains must be laid from the outfall, through the lowest parts; and into
the mains the smaller drains must be conducted, upon such a system as
that there may be the proper fall or inclination throughout, and that
the whole field shall be embraced.

Again, a perfect _plan_ of the completed work, accurately drawn on
paper, should always be preserved for future reference. Now it is
manifest, that it is impossible to lay out a given field, with proper
mains and small drains, dividing the fall as equally as practicable
between the different parts of an undulating field, preserving a system
throughout, by which, with the aid of a plan, any drain may at any time
be traced, without making distances conform somewhat to the system of
the whole.

It is easily demonstrable, too, that drains at right angles with the
mains, and so parallel with each other, are the shortest possible drains
in land that needs uniform drainage. They take each a more uniform share
of the water, and serve a greater breadth of soil than when laid at
acute angles. While, therefore, it may be supposed that in particular
parts of the field, distances somewhat greater or less might be
advisable, considered independently, yet in practice, it will be found
best, usually, to pay becoming deference to order, "Heaven's first law,"
and sacrifice something of the individual good, to the leading idea of
the general welfare.

In the letter of Mr. Denton, in another chapter, some remarks will be
found upon the subject of which we are treating. The same gentleman has,
in a published paper, illustrated the impossibility of strict adherence
to any arbitrary rule in the distances or arrangement of drains, as
follows:

"The wetness of land, which for distinction's sake, I have called
'the water of pressure,' like the water of springs, to which it is
nearly allied, can be effectually and cheaply removed only by
drains devised for, and devoted to the object. Appropriate deep
drains at B B B, for instance, as indicated in the dark vertical
lines, are found to do the service of many parallel drains, which
as frequently miss, as they hit, those furrows, or 'lips,' in the
horizontal out-crop of wa