Petroleum is the latest of the earth’s riches which man has learned to adapt to his needs. The use of iron, for instance, goes back to prehistoric times, and the same is true of nearly all metals, precious and otherwise, of salt and many other of our mineral products which the chemistry of creation has provided in the crust of this terrestrial sphere. But for countless centuries man went his way knowing of the existence of petroleum, yet utilizing it only in a sporadic and casual manner, until American ingenuity and adaptability--working in coöperation with scientists of other lands--made it the marvelous agent that it is to-day. And all this has happened since the grandfathers of most of the younger generation of the twentieth century were born. The word petroleum comes from two Latin terms signifying “rock” and “oil”. “Rock-oil,” which was an early name given it on this continent, is accounted for by the fact that certain shales and coals possess oil as part of their constituents. It is one of the family of bitumens, which even in their natural state assume many forms. In its commercial sense the word “petroleum” is a generic term covering the whole group of hydro-carbons--the refined or manufactured products as well as the crude oil. But as yet scientists are divided in opinion as to its origin and the extent of the world’s supply. All we know is that it is diffused over almost every section of the earth, and that new deposits--on the scientific development of which geologists are constantly at work--are ever being discovered. One school of scientists holds that it is of inorganic origin, derived from metallic carbides lying below the porous strata which serve as Nature’s reservoirs for the crude product that is “mined” by the modern oil producer. But the more widely accepted view is that crude petroleum is of organic origin, born of either animal or vegetable matter embedded in the earth’s surface, which in the process of decay or transmutation has taken this form. Travellers state that in the neighbourhood of the Caspian Sea the conversion of such organic matter into petroleum is visibly in operation to-day. The British scientist, Sir Boverton Redwood, in explaining the natural process by which petroleum came into existence, has pointed out that in the comparatively deep and quiescent water along the margin of the land in past there would be abundant opportunity for the accumulation of deposits of the remains of marine animals and plants, as well as of vegetable matter from the land, borne down to the coast by water courses. The changes which the world has undergone would result in the burial of these accumulations under sedimentary strata, during the process of creating land where once was water.