he manure
and finer portions of the soil are, to a great extent, washed away into
the open ditches and lost. Of the water which filters downwards, a large
portion enters open ditches near the surface, before the fertilizing
elements have been strained out; whereas, in covered drains of proper
depth, the water is filtered through a mass of soil sufficiently deep to
take from it the fertilizing substances, and discharge it, comparatively
pure, from the field. In a paper by Prof. Way (11th Jour. Roy. Ag.
Soc.), on "The Power of Soils to retain Manure," will be found
interesting illustrations of the filtering qualities of different kinds
of soil.

In addition to the above reasons for preferring covered drains, it has
been asserted by one of the most skillful drainers in the world (Mr.
Parkes), "that a proper covered drain of the same depth as an open
ditch, will drain a greater breadth of land than the ditch can effect.
The sides of the ditch," he says, "become dried and plastered, and
covered with vegetation; and even while they are free from vegetation,
their absorptive power is inferior to the covered drain."

Of the depth, direction, and distance of drains, our views will be found
under the appropriate heads. They apply alike to open and covered
drains.

BRUSH DRAINS.

Having a farm destitute of stones, before tiles were known among us, we
made several experiments with covered drains filled with brush. Some of
those drains operated well for eight or ten years; others caved in and
became useless in three or four years, according to the condition of the
soil.

In a wet swamp a brush drain endures much longer than in sandy land,
which is dry a part of the year, because the brush decays in dry land,
but will prove nearly imperishable in land constantly wet. In a peat or
muck swamp, we should expect that such drains, if carefully constructed,
might last twenty years, but that in a sandy loam they would be quite
unreliable for a single year.

Our failure on upland with brush drains, has resulted, not from the
decay of the wood, but from the entrance of sand, which obstructed the
channel. Moles and field-mice find these drains the very day they are
laid, and occupy them as permanent homes ever after.

Those little animals live partly upon earth-worms, which they find by
burrowing after them in the ground, and partly upon insects, and
vegetation above ground. They have a great deal of business, which
requires conven