soonest and longest.--Pressure of Water on
Pipes.--Durability of Tile Drains.--Drain-Bricks 100 years old.

WHAT ARE DRAIN-TILES?

This would be an absurd question to place at the head of a division in a
work intended for the English public, for tiles are as common in England
as bricks, and their forms and uses as familiar to all. But in America,
though tiles are used to a considerable extent in some localities,
probably not one farmer in one hundred in the whole country ever saw
one.

The author has recently received letters of inquiry about the use and
cost of tiles, from which it is manifest that the writers have in their
mind as tiles, the square bricks with which our grandfathers used to lay
their hearths.

In Johnstone's _Report to the Board of Agriculture on Elkington's System
of Draining_, published in England in 1797, the only kind of tiles or
clay conduits described or alluded to by him, are what he calls
"draining-bricks," of which he gives drawings, which we transfer to our
pages precisely as found in the American edition. It will be seen to be
as clumsy a contrivance as could well be devised.

[Illustration: Fig. 26.--DRAINING-BRICKS.]

So lately as 1856, tiles were brought from Albany, N. Y., to Exeter, N. H.,
nearly 300 miles, by railway, at a cost, including freight, of $25 a
thousand for two-inch pipes, and it is believed that no tiles were ever
made in New Hampshire till the year 1857. These facts will soon become
curiosities in agricultural literature, and so are worth preserving.
They furnish excuse, too, for what may appear to learned agriculturists
an unnecessary particularity in what might seem the well-known facts
relative to tile-drainage.

Drain-tiles are made of clay of almost any quality that will make
bricks, moulded by a machine into tubes, or into half-tube or horse-shoe
forms, usually fourteen inches long before drying, and burnt in a
furnace or kiln to be about as hard as what are called hard-burnt
bricks. They are usually moulded about half an inch in thickness,
varying with the size and form of the tile. The sizes vary from one inch
to six inches, and sometimes larger, in the diameter of the bore. The
forms are also very various; and as this is one of the most essential
matters, as affecting the efficiency, the cost, and the durability of
tile-drainage, it will be well to give it critical attention.

THE FORMS OF TILES.

The simplest, cheapest, and best form of dra