Page:Remarks on the Present System of Road Making (1823).djvu/191

gravel is from 3s. 6d. to 5s. The cost of granite paving, 9 inches deep, is from 8s. 6d. to 10s. 6d. per superficial yard, or from 750l. to 920l. per mile for every yard in width. Guernsey granite is harder and more durable than Aberdeen granite, but is more expensive by about 10 per cent. and I think is this much better. Some stone of very good quality from near Greenock, has been used lately upon the Commercial Road, it is cheaper than Aberdeen, and appears to be very durable. The requisites for forming a good paving are to have the stones properly squared and shaped, not as wedges, but nearly as rectangular prisms; to sort them into classes according to their sizes, so as to prevent unequal sinking, which is always the effect of stones, or rows of stones, of unequal sizes being mixed together; to have a foundation properly consolidated before the road is begun to be paved, and to have the stones laid with a close joint, the courses being kept at right angles from the direction of the sides, and in perfectly straight lines, the joints carefully broken, that is, so that the joint between two stones in any one course shall not be in a line with, or opposite to a joint in any of the two courses adjoining. After the stones are laid they are to be well rammed, and such of the stones as appear to ram loose, should be taken out and replaced by others; after this the joints are to be filled with fine gravel, and if it can be done conveniently, the stability of the work will be increased by well watering at night the part that has been done during the day, and ramming it over again next morning. The surface of the pavement is then to be covered with an inch or so of fine gravel, that the joints may be always kept full, and that the wheels may not come in contact with the stones while they are at all loose in their places. Attention to these points will very much increase both the smoothness and durability of the paving. I have found great advantage from filling up, or, as it is