ing in of its banks. It can be easily cleared of snow,
weeds, and rubbish; the water will run into it easily from
each side, and it is not dangerous to wagons and foot
travelers. It is therefore a much better ditch than the
kind of ditch very often dug by erosion along the country
roadside."

Where the road is built on a grade some provision should be made to
prevent the wash of the gutters into great, deep gullies. This can be
done by paving the bottom and sides of the gutters with brick, river
rocks, or field stone. In order to make the flow in such side ditches as
small as possible it is advisable to construct outlets into the adjacent
fields or to lay underground pipes or tile drains with openings into the
ditches at frequent intervals.

The size of side ditches should depend upon the character of the soil
and the amount of water they are expected to carry. If possible they
should be located three feet from the edge of the traveled roadway, so
that if the latter is fourteen feet wide there will be twenty feet of
clear space between ditches.

The bottom of the ditch may vary in width from three to twelve inches,
or even more, as may be found necessary in order to carry the largest
amount of water which is expected to flow through it at any one time.
Sometimes the only ditches necessary to carry off the surface water are
those made by the use of the road machines or road graders. The blade of
the machine may be set at any desired angle, and when drawn along by
horses, cuts into the surface and moves the earth from the sides toward
the center, forming gutters alongside and distributing the earth
uniformly over the traveled way. Such gutters are liable to become
clogged by brush, weeds, and other debris, or destroyed by passing
wagons, and it is therefore better, when the space permits, to have the
side ditches above referred to, even if the road be built with a road
machine.

In order to have a good road it is just as necessary that water should
not be allowed to attack the substructure from below as that it should
not be permitted to percolate through it from above. Especially is the
former provision essential in cold climates, where, if water is allowed
to remain in the substructure, the whole roadway is liable to become
broken up and destroyed by frost and the wheels of vehicles. Therefore,
where the road runs through low wet lands or over certain kinds of
clayey soils, surface dra