"saponify"; that is to say, they do not form those combinations with alkalis and other bases which are called "soaps," nor can they serve as food to man or any other animal. They are not acted on by the digestive juices. From ancient times natural deposits or outpourings of "bitumens" have been known and used by mankind. The Assyrians and other early peoples of the East used "asphalt" (translated by the word "slime" in the English version of the Bible) in place of calcareous mortar in building; and to this day it is used largely in this country as a "damp-course" in walls built of brick. Great deposits of asphalt are found in Central America and some of the West Indian islands, and "quarried" for commercial purposes. The great pitch-lake of Trinidad yields an abundant supply. In the Val de Travers, in the Canton of Neuchatel (Switzerland), a rich deposit is worked which, mixed with earthy material, forms a road-making concrete, largely used in London and other cities, and also for main roads in country districts. The ancient Egyptians used asphalt for embalming the dead. But the ancients also knew natural springs of liquid bitumen–that which nowadays we call petroleum–some of them freely flowing like water, which would take fire and burn for long periods, and were described as fountains of "burning water." We find, as we pass from the Middle Ages to the days of geographical exploration, records of such springs of inflammable oil and of natural inflammable gas in all parts of the world–Japan, China, Burma, Persia, Galicia, Italy (Salsomaggiore), Central and North America, and of not a few in these islands–for instance, in Shropshire, Derbyshire, Sussex, Kimmeridge and various sites in the southern counties. The oil was, until the middle of the last century, valued chiefly as a medicinal application, and "Seneca oil" and "American medicinal oil" were largely sold and used as an embrocation in the United States. We owe the introduction of the name "petroleum" to Professor Silliman, who in 1855 reported upon the "rock oil or petroleum" of Venango County, Pennsylvania. The first attempt as a commercial enterprise to obtain rock-oil or petroleum by _boring_ into the strata in which there was local evidence of its existence in greater or less quantity, was made in 1854 by the Pennsylvania Rock Oil Company. After some unsuccessful attempts, when the drilling had been carried to a depth of 69 ft. the tools suddenly dropped into a subterranean cavity, and on the following day the well was found to have "struck oil," and twenty-five barrels a day were yielded by that well for some time. From here the industry spread over the States and Canada, and in 1908 the year's yield was 45,000,000 barrels.