Roads. 
287 
•of seven inches is a very serious additional difficulty in an ascent 
of four and a half degrees, to a loaded waggon the greatest radius 
of whose wheels is probably only 2 feet 9 inches. 
3. In all roads whatever, it is an error to raise the centre above 
the shoulders of the road. If there are instances in which it is 
useful, I have not yet seen them. In a road merely thrown up out 
of the common soil, where the ground is very level lengthwise of 
the road, it is perhaps as well to raise the centre, because it will 
soon be beaten flat in dry weather by being chiefly used, and in 
wet weather, when the ruts or tracks are deep it is of no conse- 
quence, because the water cannot run off* rapidly : but in all other 
cases, the convexity of the road is assuredly injurious. 
In respect to their level, lengthwise, there can be only two kinds 
of roads. The first, such as are perfectly level, of which the in- 
stances are in the United States chiefly confined to sandy situa- 
tions ; the second, such as are inclined more or less to the hori- 
zon, and which in turnpike roads are permitted by law seldom t© 
exceed in acclivity, an angle of four and a half degrees. 
In the first kind of roads, that is in level roads if in any, it might 
be supposed that a convex surface would be useful, because the 
water falling upon the road, might be thereby carried into the 
ditches on each side of it. And this would happen without injury, 
if the surface were perfectly hard, and no ruts or tracks were 
cut into it by carriage wheels. But as the construction of the 
road, and the law regulating the passing of meeting carriages oc- 
casions the sides of a convex road to be used, more than the cen- 
tre, the outer wheels will always bear the principal part of the 
load and of course cut the deepest track. If the road be perfect- 
ly horizontal, lengthwise, the water which falls on the road will run 
across the road into the outer ruts on each side, which are the 
lowest and the .deepest, and stand in them until it finds vent on to 
the shoulder in a place accidentally lower. The whole water of 
the road on each side for some distance, being discharged through 
a few of these openings, the road will be gullied across its edges— 
as daily observations may shew. But if the road were perfectly 
flat, there would not be cut so easily a leading rut on the edge, 
and the water would run off as fast as it rose above the surface in 
innumerable places, and much less rapidly. It would therefore 
gully much less, and nothing is so certain, as that, of roads entirely 
unimproved, the flattest parts are certainly not the worst, because 
