Page:Historic highways of America (Volume 15).djvu/206

 which is laid next to the earth, and four inches on top, the depth depending on the thickness of the road. If the thickness of the finished road is eight inches, the telford pavement should not exceed five inches; if it is ten or more inches deep, then the telford could be six inches. It need in no case be greater than this, as this is sufficient to form the base or foundation of the metal construction. The surface of the telford pavement should be as uniform as possible, all projecting points broken off, and interstices filled in with small stone. Care should be taken to keep the stone set up perpendicular with the roadbed and set lengthwise across the road with joints broken. This foundation should be well hammered down with sledge hammers and made hard and compact. Upon this feature greatly depends the smoothness of the surface of the road and uniform wear. If put down compactly rolling is not necessary, and if not put down solid rolling might do it damage in causing the large stones to lean and set on their edges instead of on the flat sides. I refer to instances where the road is to be ten inches and over.