The other mode of locating a highway is to seek the best attainable grade the country will permit of by winding through valleys and around and across hills. There is obviously one advantage to a perfectly straight road between two places: _it is the nearest route_. But this is about the only advantage a straight road has over a curved one. In a hilly country a straight road is frequently no shorter than a curved one, because the distance around a hill is generally no greater than over it, as the length of a pail-handle is the same whether it is vertical or in a horizontal position. In an uneven country a straight road with anything like the same grade as the curved road can only be constructed at enormous and unnecessary expense and labor. Even in a level country a road curved sufficiently to give variety of view and to conform to Hogarth's "line of beauty" is preferable to a perfectly straight road, which is always tedious to the traveller. "The road the human being travels, That on which blessing comes and goes, doth follow The river's course, the valley's playful windings, Curves round the corn-field and the hill of vines." Moreover, we are told by competent engineers that the difference in length between a straight and a slightly curved road is very small. Thus, if a road between two places ten miles apart was made to curve so that the eye could nowhere see 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. But, in any event, in road-making mere straightness should always yield to a level grade, even if thereby the distance is greatly increased; for on a good grade a horse can draw rapidly and easily a load which it would be impossible for him to draw on a steep grade. It is an accepted maxim by road-engineers that the horizontal length of a road may be advantageously increased, to avoid an ascent, by at least twenty times the perpendicular height which is to be thus saved; that is, to escape a hill a hundred feet high, it would be proper for the road to make such a circuit as would increase its length to two thousand feet. Hence it is apparent that the ordinary road in a hilly and uneven country should follow the streams as far as possible, as Nature has located them in the places best adapted for highways; and when hills are found on the line of a road they should be surmounted by passing around and across them at the easiest grades possible rather than over them at steep grades. CHAPTER III. CONSTRUCTION.