attention to minute repairs in this manner a surface may be kept in good condition until it wears so thin as to require renewal.
"In case the road be of harder material, that will not so readily combine when a thin coating is added, repairs may not be frequent, as the surface will not wear so rapidly, and immediate attention is not so important. It is usually more satisfactory in this case to make more extensive repairs at one time, as a larger quantity of material added at once may be more readily compacted to a uniform surface, the repairs taking the form of an additional layer upon the road.
"Where the material of the road surface is very hard and durable, a well-constructed road may wear quite evenly and require hardly any attention, beyond ordinary small repairs, until worn out. It is now usually considered the best practice to leave such a road to itself until it wears very thin, and then renew it by an entirely new layer of broken stone placed on the worn surface and without in any way disturbing that surface.
"If a thin layer only of material is to be
