The River La Plata was discovered in 1512 by the Spanish navigator Juan Diaz de Solis, and the La Plata territory had been brought into the possession of Spain by the end of the sixteenth century. In 1810 the territory cast off the Spanish rule, and in 1816 the independence of the United States of the Rio de la Plata was formerly declared, but it was long before a settled government was established. The present constitution dates from 1853, being modified in 1866 and 1898. The executive power is vested in a president--elected by the representatives of the fourteen provinces for a term of six years. A national congress of two chambers--a Senate and a House of Deputies--wields the legislative authority, and the republic is making rapid advances in social and political life. The national revenue for 1918 amounted to about £32,860,306, while the expenditure amounted to £34,407,074; the public debt was, at the end of 1916, about £120,000,000. There are about 22,000 miles of railway opened. The external commerce is important, the chief exports being beef and mutton, wheat, maize, and linseed, wool, skins and hides, tallow. The imports are chiefly manufactured goods. The trade is largely with Britain and France, and is increasing rapidly, the exports having advanced from £9,000,000 in 1876 and £73,200,000 in 1908 to £201,360,000 in 1920. The imports in 1920 were £170,820,000. The chief denomination of money is the dollar or _peso_, value (in gold) 4s. Buenos Ayres (or Aires) is the capital. Other towns are Rosario, Cordova, La Plata, Tucuman, Mendoza, and Santa-Fé. The population of the republic, which is rapidly increasing by immigration, was, in 1905, 5,678,197, and 8,284,266 in 1918; of the capital, 1,637,155 (1918).--BIBLIOGRAPHY: C. E. Akers, _History of South America, 1854 to 1904_; W. H. Hudson, _The Naturalist in La Plata_; Keane and Markham, _Central and South America_ (in Stanford's _Compendium of Geography and Travel_); Martinez and Lewandowski, _Argentine in the Twentieth Century_; Sir John Foster Fraser, _The Amazing Argentine_; H. Stephens, _Illustrated Descriptive Argentina_; _The Argentine Year Book_.
AR´GENTITE, sulphide of silver, a blackish or lead-grey mineral, a valuable ore of silver found in the crystalline rocks of many countries.