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Show DISCOV:,TED BY ACCIDENT. How tbe Paving .'alue of Asphalt Was Erought to Notice. ' All forms of bituminous pavements whether manufactured from natural or artificial asphalt,' are in fact artificial arti-ficial stone pavements. The industry started with the u;e of natural rock asphalt from the mines in the Val de Travers, Canton Neufchatel, Switzerland. Switzer-land. The mines were discovered in 1721, but it was in 1849 that its utility util-ity as a road covering was first noticed. no-ticed. The rock was then being mined for the purpose of extracting the bitumen contained in it for its use in medicine and the arts. It is a limestone lime-stone found impregnated with bitumen, bitu-men, of which it yields, on analysis, from eight to fourteen per cent. It was observed that pieces of rock which fell from a wagon were crushed by the wheels, and under the combined combin-ed Influence of the traffic and heat of the sun a good road surface was produced. pro-duced. A macadam road of asphalt rock was then made, which gave very good results, and finally, in 1854, a portion of the Rue Bergere was laid in Paris of compressed asphalt on a concrete foundation. In 1858 a still .' larger sample was laid, and from that time it has been laid year by year in Paris. From Paris it extended to London, being laid on Threadneedle street in 1869, and Chcapside in 1870, and in successive years on other streets. v |