in-tile is the cylinder, or
merely a tube, round outside and with a round bore.

[Illustration: Figs. 27, 28, 29.--ROUND PIPES.]

Tiles of this form, and all others which are tubular, are called
_pipes_, in distinction from those with open bottoms, like those of
horse-shoe form.

About forty years ago, as Mr. Gisborne informs us, small pipes for
land-drainage were used, concurrently, by persons residing in the
counties of Lincoln, Oxford, and Kent, who had, probably, no knowledge
of each other's operations. Most of those pipes were made with
eyelet-holes, to admit the water. Pipes for thorough-draining excited no
general attention till they were exhibited by John Read at the show at
Derby, in the year 1843. A medal was awarded to the exhibitor. Mr.
Parkes was one of the judges, and brought the pipes to the special
notice of the council. From this time, inventions and improvements were
rapid, and soon, collars were introduced, and the use of improved
machines to mould the pipes; and drainage, under the fostering
influence of the Royal Agricultural Society, became a subject of general
attention throughout the kingdom. The round pipe, or _the pipe_, as it
seems, _par excellence_, to be termed by English drainers, though one of
the latest, if not the last form of tiles introduced in England, has
become altogether the most popular among scientific men, and is
generally used in all works conducted under the charge of the Land
Drainage Companies. This ought to settle the question for us, when we
consider that the immense sum of twenty millions of dollars of public
funds has been expended by them, in addition to vast amounts of private
funds, and that the highest practical talent of the nation is engaged in
the work.

After giving some idea of the various forms of tiles in use, it is,
however, proposed to examine the question upon its merits, so that each
may judge for himself which is best.

The earliest form of tiles introduced for the purpose of
thorough-drainage, was the horse-shoe tile, so called from its shape.
The horse-shoe tile has been sometimes used without any sole to form the
bottom of the drain, thus leaving the water to run on the ground. There
can hardly be a question of the false economy of this mode, for the
hardest and most impervious soil softens under the constant action of
running water, and then the edges of the tiles must sink, or the bottom
of the drain rise, and thus destroy the work.

Various