“The surface of the street is picked by gangs of men, metal from 2¹⁄₂ to 9 inches in thickness is then laid on, a coating of sand is then spread upon it, it is watered and rolled at per kilometre ton, that is, at per ton weight of roller per kilometre travelled, at a cost of about 15·33_d._ per ton mile for the first 250,000 ton miles, and at reduced rates for additional service. The materials used for the roads are flints costing 4_s._ 6¹⁄₂_d._ per cubic yard for light traffic roads; for medium traffic, hard millstone at 11_s._ 4_d._; and for the heaviest and greatest traffic, porphyry at 15_s._ 9_d._ The average total cost of maintenance of the streets is 1_s._ 8¹⁄₂_d._ per square yard per annum for the first-class roads, and 1_s._ 1¹⁄₂_d._ for the lighter traffic; the highest cost for maintenance is as high as 10_s._ 9_d._ per square yard, the lowest 9¹⁄₄_d._ per annum.” It may be well to mention that 73 per cent. of the streets in Paris are paved, 5 per cent. are coated with asphalte, and 22 per cent. are macadamised. The contour, or best form of cross section that should be given to a roadway, has often exercised the minds of engineers, but for all practical purposes evenness of surface and regularity of section in a macadamised roadway are of more importance than the slight difference between straight lines and curves, which might only tend to confuse the workmen. Formerly it was the practice to employ a complicated gauge in the form of a straight-edge fitted with plummet or level and sliding bars, but a good eye, assisted by a long straight-edge and spirit-level and three boning rods, is generally found to be sufficient, and if the centre of the roadway is kept level with the heel of the footpath, a sightly cross-section is generally the result; or say 6 inches to 9 inches higher in centre of a roadway 30 feet in width between the kerbs, 3 inches to 4 inches where it is from 18 to 20 feet in width. The following detailed section of a macadamised roadway is one which I am in the habit of specifying for suburban districts, as it is easily set out and constructed, and answers all purposes most admirably. [Illustration] The total width of street is 36 feet, of which the roadway takes 24, leaving a footpath 6 feet in width on each side. The surface of the finished roadway is a segment of a circle, the crown being level with the heels of the footpaths on each side; the formation surface is parallel with it, and of course the depth of this and the thickness of foundations and metal must depend upon local circumstances. It will be seen that the haunches are drained with 3-inch common drain-pipes. This may be omitted if the ground is thoroughly dry, but it is often a great help to a road. The paths, kerbing, and channelling will be described in their respective chapters. It must be borne in mind that on a perfectly level road a more convex section is necessary than on a gradient.