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 ...

PLANK ROADS. 231
In the most generally approved system, two parallel
rows of small sticks of timber (called indifferently sleepers, stringers, or szlls) are imbedded in the road, three or
four feet apart. Planks, eight feet long and three or four
inches thick, are laid upon these sticks, across them, at
right angles to their direction. A side track of earth, to
turn out upon, is carefully graded. Deep ditches are dug
on each side, to ensure perfect drainage; and thus is
formed a Plank Road.
The benefits of covering the earth with some better
material have been indicated on page 188, and the peculiar advantages of this plank covering will be more fully
made known, when we shall have discussed in order the
various details of construction.*
LAYING THEM OUT.
The waste of labor caused by unnecessary ascents in
a road, has been pointed out in the early part of this vol
ume, (pages 32-36.) It was also shown (page 28) thai
it is profitable to the traveller to go two or three thousand
feet around to avoid ascending a hill a hundred feet high;
though the cost of constructing the additional length of
road partially counterbalances this consideration. It was
also proved that the smoother the surface of the road was
made, the more injurious proportionally were such ascents. They are therefore especially objectionable on
plank roads, which hold an intermediate place between
common roads and railroads. Some distinguished engi* Hon. Philo White's report to the Council of Wisconsin, February,
1848, embodies a very extended and systematic collection of information
on this subject. To it, and to the valuable published and obliging private
communications of Hon. George Geddes, C. E., (who first introduced and
naturalized this improvement in the United States,) the author is muncl
indebted, as also to many other recent sources.