Page:Historic highways of America (Volume 15).djvu/97

 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