seems to remain in the minds of many writers on drainage a
glimmering of the old fallacy that underdrains, like open drains, receive
their water from above, and it is too commonly recommended that porous
substances be placed above the tile. If, as is universally conceded, the
water rises into the tile from below, this is unnecessary. The practice of
covering the joints, and even covering the whole tile, (often to the depth
of a foot,) with tan-bark, turf, coarse gravel, etc., is in no wise to be
commended; and, while the objections to it are not necessarily very grave
in all cases, it always introduces an element of insecurity, and it is a
waste of money, if nothing worse.

The tile layer need not concern himself with the question, of affording
entrance room for the water. Let him, so far as the rude materials at hand
will allow, make the joints perfectly tight, and when the water comes, it
will find ample flaws in his work, and he will have been a good workman if
it do not find room to flow in a current, carrying particles of dirt with
it.

In ditches in which water is running at the time of laying the tiles, the
process should follow closely after the grading, and the stream may even
be dammed back, section after section, (a plugged tile being placed under
the dam, to be afterwards replaced by a free one,) and graded, laid and
covered before the water breaks in. There is one satisfaction in this kind
of work,--that, while it is difficult to lay the drain so thoroughly well
as in a dry ditch, the amount of water is sufficient to overcome any
slight tendency to obstruction.

*Connections.*--As has been before stated, lateral drains should always
enter at the top of the main. Even in the most shallow work, the slightly
decreased depth of the lateral, which this arrangement requires, is well
compensated for by the free outlet which it secures.

After the tile of the main, which is to receive a side drain, has been
fitted to its place, and the point of junction marked, it should be taken
up and perforated; then the end of the tile of the lateral should be so
trimmed as to fit the hole as accurately as may be, the large tile
replaced in its position, and the small one laid on it,--reaching over to
the floor of the lateral ditch. Then connect it with the lateral as
previously laid, fill up solidly the space under the tile which reaches
over to the top of the main, (so that it cannot become disturbed in
filling,) and lay