The La Plata, the outlet of the waters of central South America, is formed by the union of the Uruguay and Parana, about 150 miles from the ocean; a little lower down, at Montevideo, it is 62 miles wide and widens rapidly to the Atlantic, where it discharges more water than all the rivers of Europe. The tributaries of the Parana are fan-shaped. Its most eastern branches rise in the mountains of Brazil, within seventy miles of the Atlantic ocean; and 1500 miles away, on the other side of the continent, its most western tributaries rise only 125 miles from the Pacific. Steamers ascend the Parana, Paraguay and Cuyaba, 2100 miles to Cuyaba, and the river with its branches is navigable for 5000 miles. _The San Francisco_. The San Francisco, about 1800 miles long, rises near Rio de Janeiro and flows north about 1200 miles between parallel ranges of mountains, then turns east and forces its way through the coast range to the Atlantic ocean. It runs through the gold and diamond regions of Brazil, and has a considerable population along its banks. It has many falls and rapids, and considerable slack-water navigation. {6} GENERAL DESCRIPTION. In Asia, the different countries have natural boundaries; the people, soil and climate of one country are unlike those of others. In Europe there are few natural boundaries, though different races inhabit the several states. In South America only one dominant race is found, and though natural boundaries exist, yet they do not serve as boundaries to the different states, other than Venezuela and Guiana. Venezuela and Guiana are watered by the Orinoco and by several rivers that flow from the Amazonian mountains to the ocean. The whole coast is low and fertile, but hot and unhealthy. The principal product is sugar, raised by negroes and coolies. The interior is sultry and thickly wooded; it is inhabited by Indian tribes, the principal of which are the cannibal Caribs, and by negroes as uncivilized as any of the tribes in Africa. Guiana is controlled by the English, French, and Dutch. Cayenne, the prison for French convicts, is the capital of French Guiana. Colombia and Ecuador occupy the northwestern part of South America. They are situated on both sides of the Andes, and have every variety of climate. The country is well watered; fertile but unhealthy on the coast, fertile and healthy on the elevated plains, cold and barren on the mountains. In Brazil, besides the Amazon, La Plata and San Francisco, there are several large rivers with fertile valleys; but occasional droughts, sometimes lasting for two years, will prevent portions of Brazil from becoming densely inhabited.