as was the custom among all of the Tapuyas. Orellana, no doubt, derived the name Amazonas from the ancient Amazons (q.v.) of Asia and Africa described by Herodotus and Diodorus.
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 Rio Napo. He returned in 1639 with the Jesuit fathers Acuña and Artieda, delegated by the viceroy of Peru to accompany him.
The river Amazon has a drainage area of 2,722,000 sq. m., if the Tocantins be included in its basin. It drains four-tenths of South America, and it gathers its waters from 5° N. to 20° S. latitude. Its most remote sources are found on the inter-Andean plateau, but a short distance from the Pacific Ocean; and, after a course of about 4000 m. through the interior of Peru and across Brazil, it enters the Atlantic Ocean on the equator. It is generally accepted by geographers that the Marañon, or Upper Amazon, rises in the little lake, Lauricocha, in 10° 30′ S. latitude, and 100 m. N.N.E. of Lima. They appear to have followed the account given by Padre Fritz which has since been found incorrect. According to Antonio Raimondi, it is the Rio de Nupe branch of the small stream which issues from the lake that has the longer course and the greater volume of water. The Nupe rises in the Cordillera de Huayhuath and is the true source of the Marañon. There is a difference among geographers as to where the Marañon ends and the Amazon begins, or whether both names apply to the same river. The Pongo de Manseriche, at the base of the Andes and the head of useful navigation, seems to be the natural terminus of the Marañon; and an examination of the hydrographic conditions of the great valley makes the convenience and accuracy of this apparent. Raimondi terminates the Marañon at the mouth of the Ucayali, Reclus the same, both following the missionary fathers of the colonial period. C. M. de la Condamine uses “Amazon” and “Marañon” indiscriminately and considers them one and the same. Smyth and Lowe give the mouth of the Javary as the eastern limit, as does d’Orbigny. Wolf, apparently uncertain, carries the “Marañon or Amazon” to the Peruvian frontier of Brazil at Tabatinga. Other travellers and explorers contribute to the confusion. This probably arises from the rivalry of the Spaniards and Portuguese. The former accepted the name Marañon in Peru, and as the missionaries penetrated the valley they extended the name until they reached the mouth of the Ucayali; while, as the Portuguese ascended the Amazon, they carried this name to the extent of their explorations. Beginning with the lower river we propose to notice, first, the great affluents which go to swell the volume of the main stream.
Tributaries.
The Tocantins is not really a branch of the Amazon, although usually so considered. It is the central fluvial artery of Brazil, running from south to north for a distance of about 1500 m. It rises in the mountainous district known as the Pyreneos; but its more ambitious western affluent, the Araguay, has its extreme southern headwaters on the slopes of the Serra Cayapó, and flows a distance of 1080 m. before its junction with the parent stream, which it appears almost to equal in volume. Besides its main tributary, the Rio das Mortes, it has twenty smaller branches, offering many miles of canoe navigation. In finding its way to the lowlands, it breaks frequently into falls and rapids, or winds violently through rocky gorges, until, at a point about 100 m. above its junction with the Tocantins, it saws its way across a rocky dyke for 12 m. in roaring cataracts. The tributaries of the Tocantins, called the Maranhão and Paraná-tinga, collect an immense volume of water from the highlands which surround them, especially on the south and south-east. Between the latter and the confluence with the Araguay, the Tocantins is occasionally obstructed by rocky barriers which cross it almost at a right angle. Through these, the river carves its channel, broken into cataracts and rapids, or cachoeiras, as they are called throughout Brazil. Its lowest one, the Itaboca cataract, is about 130 m. above its estuarine port of Cametá, for which distance the river is navigable; but above that it is useless as a commercial avenue, except for laborious and very costly transportation. The flat, broad valleys, composed of sand and clay, of both the Tocantins and its Araguay branch are overlooked by steep bluffs. They are the margins of the great sandstone plateaus, from 1000 to 2000 ft. elevation above sea-level, through which the rivers have eroded their deep beds. Around the estuary of the Tocantins the great plateau has disappeared, to give place to a part of the forest-covered, half submerged alluvial plain, which extends far to the north-east and west. The Pará river generally called one of the mouths of the Amazon, is only the lower reach of the Tocantins. If any portion of the waters of the Amazon runs round the southern side of the large island of Marajo into the river Pará, it is only through tortuous, natural canals, which are in no sense outflow channels of the Amazon.
The Xingú, the next large river west of the Tocantins, is a true tributary of the Amazon. It was but little known until it was explored in 1884–1887 by Karl von den Steinen from Cuyabá. Travelling east, 240 m., he found the river Tamitatoaba, 180 ft. wide, flowing from a lake 25 m. in diameter. He descended this torrential stream to the river Romero, 1300 ft. wide, entering from the west, which receives the river Colisú. These three streams form the Xingú, or Paraná-xingú, which, from 73 m. lower down, bounds along a succession of rapids for 400 m. A little above the head of navigation, 105 m. from its mouth, the river makes a bend to the east to find its way across a rocky barrier. Here is the great cataract of Itamaracá, which rushes down an inclined plane for 3 m. and then gives a final leap, called the fall of Itamaracá. Near its mouth, the Xingú expands into an immense lake, and its waters then mingle with those of the Amazon through a labyrinth of caños (natural canals), winding in countless directions through a wooded archipelago.
The Tapajos, running through a humid, hot and unhealthy valley, pours into the Amazon 500 m. above Pará and is about 1200 m. long. It rises on the lofty Brazilian plateau near Diamantino in 14° 25′ S. lat. Near this place a number of streams unite to form the river Arinos, which at latitude 10° 25′ joins the Juruena to form the Alto Tapajos, so called as low down as the Rio Manoel, entering from the east. Thence to Santarem the stream is known as the Tapajos. The lower Arinos, the Alto Tapajos and the Tapajos to the last rapid, the Maranhão Grande, is a continuous series of formidable cataracts and rapids; but from the Maranhão Grande to its mouth, about 188 m., the river can be navigated by large vessels. For its last 100 m. it is from 4 to 9 m. wide and much of it very deep. The valley of the Tapajos is bordered on both sides by bluffs. They are from 300 to 400 ft. high along the lower river; but, a few miles above Santarem, they retire from the eastern side and only approach the Amazon flood-plain some miles below Santarem.
The Madeira has its junction with the Amazon 870 m. by river above Pará, and almost rivals it in the volume of its waters. It rises more than 50 ft. during the rainy season, and the largest ocean steamers may ascend it to the Fall of San Antonio, 663 m. above its mouth; but in the dry months, from June to November, it is only navigable for the same distance for craft drawing from 5 to 6 ft. of water. According to the treaty of San Ildefonso, the Madeira begins at the confluence of the Guaporé with the Mamoré. Both of these streams have their headwaters almost in contact with those of the river Paraguay. The idea of a connecting canal is based on ignorance of local conditions. San Antonio is the first of a formidable series of cataracts and rapids, nineteen in number, which, for a river distance of 263 m., obstruct the upper course of the Madeira until the last rapid called Guajará Merim (or Small Pebble), is reached, a little below the union of the Guaporé with the Mamoré. The junction of the great river Beni with the Madeira is at the Madeira Fall, a vast and grand display of reefs, whirlpools and boiling torrents. Between Guajará-Merim and this fall, inclusive, the Madeira receives the drainage of the north-eastern slopes of the Andes, from Santa Cruz de la Sierra to Cuzco, the whole of the south-western slope of Brazilian Matto Grosso, and the northern one of the Chiquitos sierras, an area about
