Page:Popular Science Monthly Volume 58.djvu/236

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228
POPULAR SCIENCE MONTHLY.

While it might be interesting to describe in detail all the minerals mentioned in this table, we are at present concerned with only two, viz., asphaltums and asphaltes. Again, while it might be interesting to describe asphaltums and asphaltes from all the many localities in which they occur, we are at present concerned only with those in use in street paving, and particularly those in use in the United States.

It is said that the idea of constructing a roadway of asphalte was first suggested by the observation that lumps of asphalte that have dropped from carts upon a road, when trodden by animals and rolled beneath wheels, became compacted into a homogeneous and resisting surface. These observations were made in eastern France, in the valley of the Rhone, where very extensive deposits occur, extending into Switzerland. They were first brought into notice, about 1721, by Eirnis

Fig. 1. The Pitch Lake in Trinidad as it Appeared Before 1890.

d'Erynys, a Greek physician, who published a pamphlet in which were described deposits of sand and limestone saturated with bitumen that he had discovered some years previously in the Val de Travers, Canton of Neufchâtel, Switzerland. He described also a bituminous distillate which he used in the treatment of disease. He compared the deposits to similar beds in the valley of Siddim, near Babylon. They were forgotten for nearly a century and then re-discovered.

By whom this material was first used in road building is unknown. Early in 1850, M. de Coulaine published a paper in the ’Annales des Ponts et Chausses’ in which he discussed the use of bitumen in road building as if it was an established industry. He states, without giving any date, that the first attempt to construct a street of bitumen in Paris was made upon the Place Louis XV., opposite the Church of Saint