are laid not far below the sod. Year by year these pipes
are stopped by roots. Trees are very capricious in this matter. I was told
by the late Sir R. Peel that he sacrificed two young elm trees in the park
at Drayton Manor to a drain which had been repeatedly stopped by roots.
The stoppage was nevertheless repeated, and was then traced to an elm tree
far more distant than those which had been sacrificed. Early in the autumn
of 1850 I completed the drainage of the upper part of a boggy valley,
lying, with ramifications, at the foot of marly banks. The main drains
converge to a common outlet, to which are brought one 3-inch pipe and
three of 4 inches each. They lie side by side, and water flows perennially
through each of them. Near to this outlet did grow a red willow. In
February, 1852, I found the water breaking out to the surface of the
ground about 10 yards above the outlet, and was at no loss for the cause,
as the roots of the red willow showed themselves at the orifice of the
3-inch and of two of the 4-inch pipes. On examination I found that a root
had entered a joint between two 3-inch pipes, and had traveled 5 yards to
the mouth of the drain, and 9 yards up the stream, forming a continuous
length of 14 yards. The root which first entered had attained about the
size of a lady's little finger; and its ramifications consisted of very
fine and almost silky fibres, and would have cut up into half a dozen
comfortable boas. The drain was completely stopped. The pipes were not in
any degree displaced. Roots from the same willow had passed over the
3-inch pipes, and had entered and entirely stopped the first 4-inch drain,
and had partially stopped the second. At a distance of about 50 yards a
black Italian poplar, which stood on a bank over a 4-inch drain, had
completely stopped it with a bunch of roots. The whole of this had been
the work of less than 18 months, including the depth of two winters. A
3-inch branch of the same system runs through a little group of black
poplars. This drain conveys a full stream in plashes of wet, and some
water generally through the winter months, but has not a perennial flow. I
have perceived no indication that roots have interfered with this drain. I
draw no general conclusions from these few facts, but they may assist
those who have more extensive experience in drawing some, which may be of
use to drainers."

Having considered some of the principles on which our work should be
based, l