A manual of the principles and practice of road-making: comprising the location, construction, and improvement of roads, (common, macadam, paved, plank, etc.) and rail-roads. By W. M. Gillespie ...

EXCAVATION. 155
Steam has been applied to excavation, and a machine
co structed, which can dig and load 1000 cubic yards per
cay, in favorable soil at an annual cost, including interest, wear and tear, labor, &c., of $7,500, making the
$7,500
cost per cubic yard, 300 x 1000 = 2 cents.*
SCRAPER OR SCOOP.
This implement may be used with much advantage,
when the earth yields readily to the plough, and is not to
be moved more than 100 feet horizontally, nor to be
raised to vertical heights of more than 15 feet; though
these limits may sometimes be exceeded. The slopes of
the banks which it forms, should not be steeper than 1to 1. It usually contains'- of a cubic yard.t The
Fig. 74.
ground, except when soft or sandy, requires to be previ
ously ploughed. The scraper is drawn by two horses,
managed by a boy. The driver elevates the handles, and
the iron-shod edge runs under the loose earth, rising up
* Journal of the Franklin Institute, September, 1843.
t Ibid, October, 1841.