Asphalt

or mineral] pitch, a natural mixture of carbon and its compounds, containing from 77 to 88 per cent. of carbon, 7 to 9 per cent. of hydrogen, together with oxygen and some nitrogen, It occurs in various countries, mostly tropical; and in different geological formations. It is black or brownish-black, and may be a viscid dull paste or a lustrous solid with a conchoidal fracture, In Trinidad it forms a lake of 99 acres, varying in. solidity and giving off sulphuretted hydrogen. In the Val de Travers in the canton of Neufchatel i¢ _ occurs under the form known as asphalt-stone, a limestone impregnated with bituminous matter, It is largely used for pavements and in preparing - roofing-felts.