ch
are large enough to break or disturb the tiles in falling on to them.

If the bottom of the ditch consists of quicksand or other silty matters,
clay or some other suitable earth should be sought in that which was
excavated from a less depth, or should be brought from another place. A
thin layer of this having been placed in the bottom of the ditch when
grading, a slight covering of the same about the tiles will so encase them
as to prevent the entrance of the more "slippy" soil.

The first covering of fine earth, free from stones and clods, should be
sprinkled gently over the tiles, no full shovelfuls being thrown on to
them until they are covered at least six inches deep. When the filling has
reached a height of from fifteen to twenty inches, the men may jump into
the ditch and tramp it down evenly and regularly, not treading too hard in
any one place at first. When thus lightly compacted about the tile, so
that any further pressure cannot displace them, the filling should be
repeatedly rammed, (the more the better,) by two men standing astride the
ditch, facing each other, and working a maul, such as is shown in Figure
38, and which may weigh from 80 to 100 pounds.

[Illustration: Fig. 38 - MAUL FOR RAMMING.]

Fig. 38 - MAUL FOR RAMMING.

Those to whom this recommendation is new, will, doubtless, think it
unwise. The only reply to their objection must be that others who shared
their opinion, have, by long observation and experience, been convinced of
its correctness. They may practically convince themselves of the value of
this sort of covering by a simple and inexpensive experiment: Take two
large, water-tight hogsheads, bore through the side of each, a few inches
from the bottom, a hole just large enough to admit a 1-1/4-inch tile;
cover the bottom to the hight of the lower edge of the hole with strong,
wet clay, beaten to a hard paste; on this, lay a line of pipes and
collars,--the inner end sealed with putty, and the tile which passes
through the hole so wedged about with putty, that no water could pass out
between it and the outside of the hole. Cover the tile in one hogshead
with loose gravel, and then fill it to the top with loose earth. Cover the
tile in the other, twenty inches deep, with ordinary stiff clay, (not wet
enough to _puddle_, but sufficiently moist to pack well,) and ram it
thoroughly, so as to make sure that the tiles are completely clasped, and
that the