hrown out, but as soon
as the maker saw that they were really inspected, he sent tile of good
quality only. Care should also be taken that no _over-burned_ tile,--such
as have been melted and warped, or very much contracted in size by too
great heat,--be smuggled into the count.

A little practice will enable an ordinary workman to throw out those which
are imperfect, and, as a single tile which is so underdone that it will
not last, or which, from over-burning, has too small an orifice, may
destroy a long drain, or a whole system of drains, the inspection should
be thorough.

The collars should be examined with equal care. Concerning the use of
these, Gisborne says:

"To one advantage which is derived from the use of collars we have not yet
adverted--the increased facility with which free water existing in the soil
can find entrance into the conduit. The collar for a 1-1/2-inch pipe has a
circumference of three inches. The whole space between the collar and the
pipe on each side of the collar is open, and affords no resistance to the
entrance of water; while at the same time the superincumbent arch of the
collar protects the junction of two pipes from the intrusion of particles
of soil. We confess to some original misgivings that a pipe resting only
on an inch at each end, and lying hollow, might prove weak and liable to
fracture by weight pressing on it from above; but the fear was illusory.
Small particles of soil trickle down the sides of every drain, and the
first flow of water will deposit them in the vacant space between the two
collars. The bottom, if at all soft, will also swell up into any vacancy.
Practically, if you reopen a drain well laid with pipes and collars, you
will find them reposing in a beautiful nidus, which, when they are
carefully removed, looks exactly as if it had been moulded for them."

The cost of collars should not be considered an objection to their use;
because, without collars it would not be safe, (as it is difficult to make
the orifices of two pieces come exactly opposite to each other,) to use
less than 2-inch tiles, while, with collars, 1-1/4-inch are sufficient for
the same use, and, including the cost of collars, are hardly more
expensive.

It is usual, in all works on agricultural drainage, to insert tables and
formulae for the guidance of those who are to determine the size of tile
required to discharge the water of a certain area. The practice is not
adopted here, for the