brush or other
rubbish, or furnished with several lengths of tile set on end, one above
the other, or with a barrel or other vessel; and a line of tile of proper
size should be run directly to a main, or sub-main drain. The manner of
doing this by means of a pit filled with stone is shown in Fig. 10. The
collection of spring water in a vertical tile basin is shown in Fig. 11.

[Illustration: Fig. 11 - STONE AND TILE BASIN FOR SPRING WITH DRAIN.]

Fig. 11 - STONE AND TILE BASIN FOR SPRING WITH DRAIN.

5. Where a ledge of shelving rock, of considerable size, occurs on land to
be drained, it is best to make some provision for collecting, at its base,
the water flowing over its surface, and taking it at once into the drains,
so that it may not make the land near it unduly wet. To effect this, a
ditch should be dug along the base of the rock, and _quite down to it_,
considerably deeper than the level of the proposed drainage; and this
should be filled with small stones to that level, with a line of tile laid
on top of the stones, a uniform bottom for the tile to rest upon being
formed of cheap strips of board. The tile and stone should then be covered
with inverted sods, with wood shavings, or with other suitable material,
which will prevent the entrance of earth, (from the covering of the
drain,) to choke them. The water, following down the surface of the rock,
will rise through the stone work and, entering the tile, will flow off.
This method may be used for springy hill sides.

6. The points previously considered relate only to the collection of
unusual quantities of water, (from springs and from rock surfaces,) and to
the removal from the land of what is thus collected, and of that which
flows from the minor or lateral drains.

The _lateral drains_ themselves constitute the real drainage of the field,
for, although main lines take water from the land on each side, their
action in this regard is not usually considered, in determining either
their depth or their location, and they play an exceedingly small part in
the more simple form of drainage,--that in which a large tract of land, of
perfectly uniform slope, is drained by parallel lines of equal length, all
discharging into a single main, running across the foot of the field. The
land would be equally well drained, if the parallel lines were continued
to an open ditch beyond its boundary,--the main tile drain is only adopted
for greater convenienc