The geographical distribution of petroleum is as wide relatively as its geologic range. The oil fields of present commercial significance are situated, in the order of their importance as contributors to the world’s production of petroleum in 1917, in the United States, Russia, Galicia, Mexico, Dutch East Indies, India, Persia, Japan and Formosa, Roumania, Peru, Trinidad, Argentina, Egypt, Germany, Canada, Venezuela and Italy. Small quantities of petroleum have also been reported from Guatemala, Honduras, Costa Rica, Panama, Haiti, Porto Rico, Bolivia, Chile, Spain, Arabia, China, Australia, Papua, Philippine Islands, Nigeria, Belgian Congo, Gold Coast, Madagascar, and elsewhere. The geographical distribution of petroleum in the world is shown on the accompanying map. (Plate I.) [Illustration: PLATE I.--Geographical distribution of the producing petroleum fields of the world. By John D. Northrop.] In the opinion of the author the most conspicuous developments of the world’s supply of petroleum in the next decade will take place in the countries that border the Caribbean Sea and the Gulf of Mexico. The trend in this direction is unmistakable. From 1913 to 1917, the annual production of petroleum in Mexico increased from 21,000,000 barrels to 56,000,000 barrels, and the potentialities of future production in that country have been demonstrated to be almost beyond comprehension. The output, originally considered valuable only as a source of fuel oil, is now yielding, by modern refining methods, increasingly important percentages of illuminating oils and gasoline. The only obstacles to enormously increased production are unsettled political conditions and inadequate facilities for marine transportation. These obstacles will doubtless be overcome within the next few years, and barring unforeseen contingencies Mexico will soon rank second among the oil-producing countries of the world.[2] Judged by the results of exploratory work already done in Venezuela and Colombia, both of those countries are destined to contribute appreciably to the world’s supply of petroleum within the next decade. Recently Colombia has given enough evidence of ability to furnish high-grade petroleum from wells of large individual capacity to warrant the large interests holding concessions there to exert every effort to overcome the adverse natural conditions that have so long barred the way to exploitation. Enough drilling has already been done in Venezuela to demonstrate that the resources of heavy-gravity asphalt-base petroleum in that country are large, and the recent installation of a modern petroleum refinery for the treatment of these oils on the island of Curacao, off the Venezuelan coast, has provided the market necessary to active field development. [2] Mexico ranked second in 1918 and 1919.