PETROLEUM, a natural oil found in the earth, composed mainly of hydro carbons. Its existence has been known since earliest times, but it was found in large quantities only following its dis covery in Pennsylvania in 1850. Since that time there has been rapid develop ment in its production. There was a dis covery of oil fields in the United States, in Mexico, in Russia, and in Rumania. These are the chief producing countries, although oil is found in many other places on the earth's surface.
The chief feature in recent years has been the development of new oil fields in the mid-west part of the United States and in California. In 1919 377,719,000 barrels of petroleum were marketed. The total production in 1919 was 380, 000,000 barrels. Of this over 100,000, 000 barrels came from California, 116, 000,000 barrels from the Oklahoma Kansas fields, 68,000,000 barrels from the central and north Texas fields, and the remainder the Gulf Coast and Rocky Mountain fields. The consump tion of domestic crude petroleum in 1919 in the United States was 375,000,000 barrels.
The development of the internal com bustion engine, driven by gasoline, has resulted in the growth of a great indus try in the production of gasoline, which is a by-product of petroleum. The in
creased use of petroleum as fuel oil has greatly increased the consumption. The fuel oil consumption of railroads alone amount to about 40 million barrels yearly. The gasoline production in 1919 was about 3,500,000,000 gallons.
Mexico is one of the great petroleum countries. In 1919 the production was nearly 100 million barrels. The produc tion in Russia decreased greatly on ac count of the conditions resulting from the war.
The possibility of the exhaustion of petroleum fields in the United States has received considerable attention and steps are being taken to conserve the supply as far as possible, or to provide for the control of other fields from which addi tional supplies can be obtained. The world production of petroleum in 1917 was 506,702,902 barrels, of which about 335,000,000 barrels were produced in the United States.