ance of loose material, and to
hold the pipes in place during construction. The ditch should then be
filled with cinders, gravel, or coarse sand. If stones are to be used,
they should be broken to a small size,--not more than one inch in
diameter,--and the loose bits should be mixed with them in the filling.
Very small interstices will be sufficient to allow water to pass freely
through, while if large stones are used, with large interstices, there
will be danger of a washing-in of earth sufficient in time to obstruct
both the stonework and the tile. The smaller the tile, so long as it is
sufficient for its purpose, the better; for lengths of five hundred feet
or less, an interior diameter of an inch and a quarter will be
sufficient; from this to one thousand feet, use an inch and a half bore.
If possible, before exceeding this length, secure an outlet for the
water in the roadside gutter or some other channel of exit. The
tile-drain, at a depth of three feet, will remove all subsoil water from
under the walk, and all that may be delivered into the loosely filled
trench at its side. The loose filling of the trench should not be
carried nearer than within six inches of the surface of the ground, and
should be covered with fine and well-packed earth to prevent the
entrance of _surface_-water which would soon carry in silt enough to
stop its action. Whatever covering is adopted for the walk itself, it
must be of such a character as to prevent any thing like a free
admission of surface-water. Concrete will do this perfectly; and either
ashes, or gravel dressed at the top with ashes, if well raked and rolled
at the outset to a smooth surface, will soon become so bound together as
to shed pretty nearly all rain falling upon it. The difference in cost
between a walk made in this way, and one dug out for its whole width to
a depth of two feet, and filled first with stone and then with gravel
and a suitable surface dressing, will be very important; and it is safe
to say that the cheaper will be at least as good and durable as the more
expensive method. In all construction of sidewalks, whether public or
private, regard must be had to the surface conformation, and some device
must be adopted for preventing the flow of water upon the walk from the
adjoining ground, and for the easy delivery of storm-water falling upon
the walk itself.

ROADWAYS.

The great expense of Macadamizing or Telfordizing puts these systems
almost out o