Near that fork of the great river where on the one hand the black waters of the Rio Negro come down from a thousand miles' course from Venezuelan, Colombian and Ecuadorian forests and mingle with the muddy waters borne from the Peruvian Marañon and its tributaries, there stood, in the middle of last century, a riverside village of Indians, a handful of Portuguese, negroes and half-breeds. From this humble beginning a city sprang to being, the geographical and trade centre of the Amazon, with every comfort and every vice of modern civilization. What was the cause of this transformation? It was the discovery of the uses of rubber, the exploitation of the "black gold" of the forests. Manaos grew until the place, to which all the rubber-producing lands of the neighbouring Republics are tributary, provided ninety per cent. of the world's supply of rubber. It has not, however, given its name to this commodity, which has been associated rather with that of Para, another riverside city near the mouth of the Amazon, itself created largely by this trade. * * * * * "Formerly the basin of the Amazon was almost unpopulated. In 1848 the city of Belem, the only one in Amazonia, had 15,000 inhabitants, but two years later an epidemic of yellow fever greatly diminished their number. As for Manaos, even thirty years later it was only a village; Mathews, who visited it in 1879, estimated its population at 5,000. The Indian tribes of the forest refused to work; and a few thousand half-breeds, _tapuyoz_, a mixture of Portuguese, Indian and negro blood--were utterly inadequate to draw upon the wealth that men were beginning to recognize in the bordering forests. Labourers were demanded on every hand. The first immigrants, who settled about Manaos, were Indians from Bolivia and Peru; but their numbers were wholly insufficient. "It was the influx of the inhabitants of Ceará, during the draught of 1877-79, that made the development of the rubber trade possible. From that date the colonization of the forest proceeded rapidly. The seekers of rubber dispersed themselves throughout Amazonia; but the region most regularly exploited was the basin of the Rio Purus and that of the Rio Jurua. These two rivers are navigable for a greater distance upstream than any other of the affluents of the Amazon, and in the virgin forest, which the rubber-seekers were the first to invade, the exportation of rubber is only possible along the navigable water-ways. The Brazilians who mounted the Purus and the Jurua did not stop at the Bolivian frontier; a war with Bolivia very nearly broke out on the subject of these lands, which a few years earlier had not even been explored. The foundation of the independent Republic of Acré, the treaty of Petropolis, and the cession of Acré to Brazil, were the result of the westerly march of the rubber-seekers.