Note 26 — Chapter VI · ROAD METAL AND BREAKING.
Reading edition
Toughness is not all that is required. Leather would be very difficult to break with a hammer, but it would not make a good road metal.
[27] I have tried this experiment, but without success, except on such soft stones as were evidently unfitted for use as a road metal.
[28] Many hundreds of miles of roadways in this country are made with limestones; they often make an excellent surface, as they possess a considerable power of binding together, but weather and very heavy traffic affect them considerably: as they all have a strong affinity for water, their very power of thus cementing themselves together causes a quantity of dust in dry, and mud in wet weather.
[29] A flinty or quartzose stone seems to harden with exposure. This is notably the case in pebbles; old pebble paving taken up and broken makes a most hard and durable road metal.
[30] ‘Roads, Streets and Pavements,’ by Q. A. Gillmore, p. 10.
[31] Ibid.
[32] Vide ‘The Maintenance of Macadamised Roadways,’ by Thomas Codrington, p. 33, a most excellent work upon this subject.
[33] Mr. W. Bold considered a hammer weighing 1¹⁄₄ lb. of an elliptical form, pointed at the ends, the area of each end being about ¹⁄₁₀₀th of a square inch, to be the most suitable to break hard stones. Vide ‘Minutes of Proceedings, Institution of Civil Engineers,’ vol. i. (1840) p. 50.
[34] ‘The Maintenance of Macadamised Roads,’ by Thomas Codrington, p. 38.
[35, 36] No doubt the price of the machine varies with the price of iron, etc.
[37] Vide ‘Report of the Borough Surveyor of Birmingham to the Paving and Street Improvement Sub-Committee,’ p. 11.
[38] Vide ‘Proceedings of the Association of Municipal and Sanitary Engineers,’ vol. ii. p. 76.
[39] Vide ‘The Maintenance of Macadamised Roadways,’ by Thomas Codrington, p. 41.
[40] Vide ‘Proceedings of the Association of Municipal and Sanitary Engineers,’ vol. ii. p. 82.
[41] Vide ‘The Maintenance of Macadamised Roadways,’ by Thomas Codrington, p. 45.