rry the same water off the field as
speedily as possible, we should carry our surface ditch directly down
the slope.

Now, looking at the operation of drains across the slope, and supposing
that each drain is draining the breadth next above it, we will suppose
the drain to be running full of water. What is there to prevent the
water from passing out of that drain in its progress, at every point of
the tiles, and so saturating the breadth below it? Drainpipes afford the
same facility for water to soak out at the lower side, as to enter on
the upper, and there is the same law of gravitation to operate in each
case. Mr. Denton gives instances in which he has observed, where drains
were carried across the slope, in Warwickshire, lines of moisture at a
regular distance below the drains. He could ascertain, he says, the
depth of the drain itself, by taking the difference of height between
the line of the drain at the surface, and that of the line of moisture
beneath it. He says again:

"I recently had an opportunity, in Scotland, of gauging the quantity
of water traveling along an important drain carried obliquely across
the fall, when I ascertained with certainty, that, although the land
through which it passed was comparatively full of water, the drain
actually lost more than it gained in a passage of several chains
through it."

So far as authority goes, there seems, with the exception of some
advocates of the Keythorpe system, of which an account has been given,
to be very little difference of opinion. Mr. Denton says:

"With respect to the direction of drains, I believe very little
difference of opinion exists. All the most successful drainers
concur in the line of the steepest descent, as essential to
effective and economical drainage. Certain exceptions are
recognized in the West of England, but I believe it will be found,
as practice extends in that quarter, that the exceptions have been
allowed in error."

In another place, he says:

"The very general concurrence in the adoption of the line of
greatest descent, as the proper course for the minor drains in
soils free from rock, would almost lead me to declare this as an
incontrovertible principle."

Allusion has been made to cases where we may have to defend ourselves
from the flow of water from higher undrained lands of our neighbor. To
arrest the flow of mere surface wate