ixed.

The worst of all drains is an open ditch, of equal width from top to
bottom. It cannot stand a single season, in any climate or soil, without
being seriously impaired by the frosts or the heavy rains. All open
drains should be sloping; and it is ascertained, by experiment, what is
the best, or, as it is sometimes expressed, the natural slope, on
different kinds of soil. If earth be tipped from a cart down a bank, and
be left exposed to the action of the weather, it will rest, and finally
remain, at a regular angle or inclination, varying from 21 deg. to 55 deg. with
the horizon, according to the nature of the soil. The natural slope of
common earth is found to be about 33 deg. 42'; and this is the inclination
usually adopted by railroad engineers for their embankments.

If the banks of the open ditch are thus sloped, they will have the least
possible tendency to wash away, or break down by frost.

Again: where open ditches are adopted in mowing fields, they may, if not
very deep, be sloped still lower than the natural slope, and seeded down
to the bottom; so that no land will be lost, and so that teams may pass
across them.

This amounts, in fact, to the old ridge and furrow system, which was
almost universal in England before tiles were used, and is sometimes
seen practiced in this country. The land, by that system, is
back-furrowed in narrow lands, till it is laid up into beds, sloping
from the tops, or backs, to the furrows which constitute the drains.
This mode of culture is very ancient, and is probably referred to in the
language of the Psalmist, in the Scriptures: "Thou waterest the ridges
thereof abundantly, thou settlest the furrows thereof, thou makest it
soft with showers."

The objections to open ditches, as compared with under-drains, may be
briefly stated thus:

1. _They are expensive._ The excavation of a sloping drain is much
greater than that of an upright drain. An open drain must have a width
of one or two feet at the bottom, to receive the earth that always must,
to some extent, wash into it. An open drain requires to be cleaned out
once a year, to keep it in good order. There is a large quantity of
earth from an open drain to be disposed of, either by spreading or
hauling away. Thus, a drain of this kind is costly at the outset, and
requires constant labor and care to preserve it in working condition.

2. _They are not permanent._ A properly laid underdrain will last half a
century or