hey appear
on the map like a thousand ribbons streaming from a main mast, and many
of the obscure affluents, though large as the Hudson, are unknown to
geography. From three degrees north to twenty degrees south, every river
that flows down the eastern slope of the Andes is a contributor--as
though all the rivers between Mexico and Mount Hooker united their
waters in the Mississippi. While the great river of the northern
continent drains an area of one million two hundred thousand square
miles, the Amazon (not including the Tocantins) is spread over a million
more, or over a surface equal to two thirds of all Europe. Let us
journey around the grand trunk and take a glimpse of the main branches.

The first we meet in going up the left bank is the Rio Negro. It rises
in the Sierra Tunuhy, an isolated mountain group in the llanos of
Colombia, and enters the Amazon at Manaos, a thousand miles from the
sea. The upper part, down to the parallel of one degree north, has a
very rapid current; at San Gabriel are the first rapids in ascending;
between San Gabriel and Barcellos the rate is not over two or three
miles per hour; between Barcellos and Manaos it is a deep but sluggish
river, and in the annual rise of the Amazon its waters are stagnant for
several hundred miles up, or actually flow back. Its extreme length is
twelve hundred miles, and its greatest breadth is at Barcellos, where it
is twelve or fifteen miles. Excepting this middle section, the usual
breadth of the Negro below the equatorial line is about one mile. It is
joined to the Orinoco by the navigable Cassiquiari,[151] a natural canal
three fourths of a mile wide, and a portage of only two hours divides
the head of its tributary, the Branco, from the Essequibo of Guiana. The
Negro yields to commerce coffee, cacao, farina, sarsaparilla, Brazil
nuts, pitch, piassaba, and valuable woods. The commerce of Brazil with
Venezuela by the Rio Negro amounted in 1867 to $22,000, of which $9000
was the value of imports. The principal villages above Manaos are San
Miguel and Moroa (which contain about fifty dwellings each), Tireguin,
Barcellos, Toma, San Carlos, Coana, San Gabriel, and Santa Isabel.

[Footnote 151: The Cassiquiari belongs indifferently to both river
systems, the level being so complete at one point between them as to
obliterate the line of water-shed.--_Herschel_.]

The next great affluent is the Japura. It rises in the mountains of New
Granada, and, flowing