BROKEN-STONE roads consist essentially of a mass of angular fragments of rock deposited, usually in layers, upon the road-bed or a foundation prepared for it, and then consolidated to a smooth and uniform surface by means of a roller or by the action of the traffic which passes over it.
There are two commonly recognized systems of con structing broken-stone roads, differing in the nature of the foundation employed, and known respectively by the names of the men who first introduced them into English practice as Telford roads and Macadam roads.
Each of these systems has been greatly modified in use since the time of itS founder, and each name is now used to cover a general class of constructions differing very materially within itself as applied in the practice of different engineers. Each of the systems also has its earnest advocates, who contend for its exclusive use, and numerous controversies have been the result, at the conclusion of which each party is "of the same opinion still. " The view taken by different road
builders in this matter, it may be remarked, appears to be the result usually of the local necessities of the vicinities in which they work, and of the skill with which the different systems have been applied in work which has come under their observations. In road-building, as in any other class of engineering works, no rigid rules can be laid down for universal application; each road must be designed for the place it is to occupy and the work it is to do.
In some parts of this country natural' gravel is sub stituted for broken stone in the construction of these roads, the methods of construction being the same as in using broken stone.