enerally
moved out laterally to build up earth berms or "shoulders" alongside
the gravel. Into this trench the gravel is dumped in the proper
quantity to give the required thickness after being compacted.

The greatest care must be exercised in spreading the gravel to
eliminate unevenness where the loads were deposited. An ordinary blade
grader is one of the best and most economical implements to use for
spreading the gravel. When the gravel has been deposited in the trench
for a distance of a thousand feet or more, the spreading is
accomplished by dragging the surface repeatedly with the blade grader,
the work being continued until all waviness disappears. The gravel is
then thoroughly and repeatedly harrowed with a heavy stiff tooth
harrow to mix thoroughly the fine and coarse gravel so as to produce
as nearly a uniform mixture as may be. The gravel is then finally
smoothed with the blade grader.

The gravel may be compacted by rolling or may be allowed to pack from
the action of traffic. The former is greatly to be preferred where
practicable. The rolling is performed with a three-wheeled
self-propelled roller weighing about 8 tons and must be done while the
gravel is wet. Generally a sprinkling wagon is used to wet down the
gravel, but advantage is always taken of rains to facilitate the work.
The gravel must be spread in layers not over 5 or 6 inches thick to
get the desired results, which means that for an ordinary gravel road
about 10 inches thick, the gravel will be placed in two layers of
about equal thickness, each of which will be rolled.

The gravel will compact slowly even if it is not rolled, but generally
does not become stable until the material is thoroughly soaked by
rains. Then it will begin to pack, but will become badly rutted and
uneven during the process. During this period the surface must be kept
smooth by means of the blade grader. The drag does not suffice for
this purpose, tending to accentuate the unevenness rather than to
correct it.

If gravel is placed in a trench in dense soil and rainy weather
ensues, sufficient water will be held in the trench to cause
unevenness from foundation settlement and the gravel will become mixed
with the soil to some extent and be thereby wasted. Trenches cut from
the road bed upon which the gravel is placed, to the side ditches,
will relieve this condition by affording an outlet for the surplus
water. Nevertheless some difficulty may be expected if the