AMAZONIA. 93 



feet deep and about 400 feet wide. Yet the Jurua ranks only as a third-class 

 river in Brazil. 



A little below its confluence the Solimoes is joined by the Teffe, or "Deep," 

 beyond which follow on the same right bank the black Coary and the Purus, the 

 latter descending from the base of the Peruvian Andes. The Purus, essentially a 

 river of the plains and entirely fed by rainwater, was ascended by Serafim for 

 1,300 miles in 1852, by Manoel Urbano in 1860, and in 1864 — 5 by Chandless, 

 whose name has been given to one of its western affluents. The botanist, Wallis, 

 accompanied the first steamer, which in 1862 reached a point 800 miles above 

 the confluence. 



Like all the other southern affluents of the Amazons, the Purus, which has an 

 extremely winding course of about 1,850 miles, has a general north-easterly trend, 

 and brings to the main stream the contributions of several large tributaries, such as 

 the Araca, Hyuacu, Aquiry, Pauyarim, Mucuim, and Tapaua. It flows entirely in 

 the old depression, which occupies the heart of the former Amazonian sea, and 

 throughout its whole course it is entirely free from rapids or other obstructions ; 

 even islands are rare ; but its numerous meanderings are constantly shifting their 

 course owins: to the erosions of the flood waters, which even a short distance 

 above the confluence rise to a height of no less than 60 feet. Farther up the 

 inundations fill its whole valley for a distance of 15 or even 20 miles, and at 

 this season temporary branches are opened in the direction of the Amazons. But 

 the channels figured on the old maps as communicating eastwards v>^ith the 

 Madeira do not appear to have any real existence. 



The Pio Negro and its Affluents. 



Between the Purus and Madeira confluences the Solimoes becomes the 

 Amazons by the junction of the Ptio Negro ("Black Piver ") on its left bank. 

 Of the numerous watercourses bearing this name, none has a better claim to the 

 epithet, and all travellers who have visited the Parana Pixuna, as the natives call 

 it, have been struck by the contrast presented by the Pio Negro, especially at its 

 confluence with the almost milky Rio Branco ("White River"), descending from 

 the argillaceous savannas on the British Guiana frontier. The two currents flow 

 side by side, like two streams in the same bed, and during the November floods, 

 when the Rio Branco sends down a larger volume than the Rio Negro, it may be 

 distinctly traced for a distance of some 20 miles below the confluence. It is 

 noteworthy that mosquitoes do not infest the black rivers, which also abound less 

 in fish and are often avoided by crocodiles, though these saurians frequent the 

 Rio Negro. The water is limpid, but unpleasant to the taste, and apparently 

 even unwholesome, owing to the decomposed vegetable matter with which it is 

 charged, and to which it owes its dark colour. This colour, however, is percep- 

 tible only in the deeper parts, the shallow waters being of a light brown and even 

 yellowish tint. 



Of the numerous streams converging to form the Rio Negro the Rio Uaupes 

 (TJcuyaris) seems to have the best right to be regarded as its true upper course 



