This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1907 Excerpt: … the subsoil, however bad, would carry any weight if made dry by drainage and kept dry by an impervious covering. The names of both have ever since been associated with the class of road which each favored, as well as with roads on which all their precepts have been disregarded. Quality of Stones. The materials used for broken-stone pavements must of necessity vary very much according to the locality. Owing to the cost of haulage, local stone must generally be used, especially if the traffic be only moderate. If, however, the traffic is heavy, it will sometimes be found better and more economical to obtain a superior material, even at a higher cost, than the local stone; and in cases where the traffic is very great, the best material that can be obtained is the most economical. The qualities required in a good road stone are hardness and and toughness and ability to resist the disintegrating action of the weather. These qualities are seldom found together in the same stone. Igneous and siliceous rocks, although frequently hard and tough, do not consolidate so well nor so quick as limestone, owing to the sandy detritus formed by the two first having no cohesion, whilst the limestone has a detritus which acts like mortar in binding the stones together. A stone of good binding nature will frequently wear much better than one without, although it is not so hard. A limestone road well made and of good cross-section will be more impervious than any other, owing to this cause, and will not disintegrate so soon in dry weather, owing partly to this and partly to the wellknown quality which all limestone has of absorbing moisture from the atmosphere Mere hardness without toughness is not of much use, as a stone may be very hard but so brittle as to be crushed to powd…
