iles apart were made to curve so that the eye
could see no farther than a quarter of a mile of it at once, its length
would exceed that of a perfectly straight road between the same points
by only about one hundred and fifty yards." Even if the distance around
a hill be much greater, it is often more economical to construct it that
way than to go over and necessitate the expenditure of large amounts of
money in reducing the grade, or a waste of much valuable time and energy
in transporting goods that way. Gillespie says "that, as a general rule,
the horizontal length of a road may be advantageously increased to avoid
an ascent by at least twenty times the perpendicular height which is
thus to be avoided--that is, to escape a hill one hundred feet high it
would be proper for the road to make such a circuit as would increase
its length two thousand feet." The mathematical axiom that "a straight
line is the shortest distance between two points" is not, therefore, the
best rule to follow in laying out a road; better is the proverb that
"the longest way round is the shortest way home."

The grade is the most important factor to be considered in the location
of roads. The smoother the road surface, the less the grade should be.

Whether the road be constructed of earth, stone, or gravel, steep grades
should always be avoided if possible. They become covered at times with
coatings of ice or slippery soil, making them very difficult to ascend
with loaded vehicles, as well as dangerous to descend. They allow water
to rush down at such a rate as to wash great gaps alongside or to carry
the surfacing material away. As the grade increases in steepness either
the load has to be diminished in proportion or more horses or power
attached. From Gillespie we find that if a horse can draw on a level one
thousand pounds, on a rise of--

1 foot in-- Pounds

100 feet he draws 900
50 feet 810
44 feet 750
40 feet 720
30 feet 640
25 feet 540
24 feet 500
20 feet 400
10 feet 250

It is therefore seen that when the grades are 1 foot in 44 feet, or 120
feet to the mile, a horse can draw only three-fourths as much as he can
on a level; where the grade is 1 foot in 24 feet, or 220 fee