AMAZON, the great river of South America and the largest in the world in volume although exceeded in length by the Mississippi—Missouri. In the year 1500, Vicente Yafiez Pinzon, in command of a Spanish expedition, discovered and ascended the Amazon to a point about So m. from the sea. He called it the Rio Santa Maria de la Mar Dulce, which soon became ab breviated to Mar Dulce. For some years after 1502 it was known as the Rio Grande. The companions of Pinzon, in giving evidence in 1515, mention it as El Ryo Maranon.
The first descent of the river from the Andes to the sea was made in 1541 by Orellana who reached the main stream by way of the Napo River. It is rather generally accepted that the name Amazonas was given to the river by Orellana after a battle with the Tapuyas savages in which he believed that the women of the tribe fought with the men. The first ascent of the river was made in 1638 by Pedro Texiera, a Portuguese, who reversed the route of Orellana and reached Quito by way of the Napo.
The Amazon River has a drainage area of 2,722,000 sq.m. if the Tocantins is included. It drains four-tenths of South America and gathers its waters from 5° N. to S. latitude. The main stream rises in a chain of glacier-fed lakes on the eastern border of the main range of the Andes in Central Peru, about i,000 m. N.N.E. of Lima, and flows for 4,00o m. across Peru and Brazil to enter the Atlantic on the equator. While Amazon, or Amazonas, is popularly applied to the whole of the main stream it is properly applied only to sections of it in Peruvian and Brazilian nomenclature. In Peru the upper stream from its source to Iquitos is called Maranon and, from there to the sea, Amazonas. In Brazil the name Solimoes is used from Iquitos to the mouth of the Negro River and Amazonas only from the Negro River to the sea. Beginning with the lower river the great tributaries to the main stream will be discussed in order, beginning with the southern or larger affluents.