ing this
water, cool in Summer and warm in Winter, and in watching the mingled
streams of spring and drainage water, and listening as we pass by, to
their tinkling sound, which, like the faithful watchman of the night,
proclaims that "all is well."

POSITION AND SIZE OF THE MAINS.

Having fixed on the proper position of the outlet, for the whole, or any
portion of our work, the next consideration is the location of the
drains that shall discharge at that point. It is convenient to speak of
the different drains as _mains_, _sub-mains_, and _minors_. By _mains_,
are understood the principal drains, of whatever material, the office of
which is, to receive and carry away water collected by other drains from
the soil. By _minors_, are intended the small drains which receive the
surplus water directly from the soil. By _sub-mains_, are meant such
intermediate drains as are frequently in large fields, interposed across
the line of the minors, to receive their discharge, and conduct their
water to the mains.

They are principally used, where there is a greater length of small
drains in one direction than it is thought expedient to use; or where,
from the unequal surface, it is necessary to lay out subordinate systems
of drains, to reach particular localities.

Whether after the outlet is located, the mains or minors should next be
laid out, is not perhaps very important. The natural course would seem
to be, to lay out the mains according to the surface formation of the
land, through the principal hollows of the field, although we have high
authority for commencing with the minors, and allowing their
appropriate direction to determine the location of the mains.

This is, however, rather a question of precedence and etiquette, than of
practical importance. The only safe mode of executing so important a
work as drainage, is by careful surveys by persons of sufficient skill,
to lay out the whole field of operations, before the ground is broken;
to take all the levels; to compare all the different slopes; consider
all the circumstances, and arrange the work as a systematic whole.
Generally, there will be no conflict of circumstances, as to where the
mains shall be located. They must be lower than the minors, because they
receive their water. They must ordinarily run across the direction of
the minors, either at right angles or diagonally, because otherwise they
cannot receive their discharge. If, then, in general, the minors,