EABLY GEOGRAPHICAL DOUBTS. 
425 
hundred and fifty miles* before reaching Angostura, but we 
should go with the stream ; and this consideration lessened 
our discouragement. In descending great rivers, the rowers 
take the .middle of the current, where there are few mosqui- 
tos; hut in ascending, they are obliged, in order to avail them- 
selves of the dead waters and counter-currents, to sail near 
the shore, where the proximity of the forests, and the 
remains of organic substances accumulated on the beach, 
harbour the tipulary insects. The point of the celebrated 
bifurcation of the Orinoco has a very imposing aspect. Lofty 
granitic mountains rise on the northern bank; and amidst 
them are discovered at a distance the Maraguaca and the 
Duida. There are no mountains on the left bank of the 
Orinoco, west or east of the bifurcation, till opposite the 
mouth of the Tamatama. On that spot stands the rock 
Ouaraco, which is said to throw out flames from time to 
time in the rainy season. When the Orinoco is no longer 
bounded by mountains towards the south, and when it 
reaches the opening of a valley, or rather a depression of the 
ground, which terminates at the Eio Negro, it divides itself 
mto two branches. The principal branch (the Rio Paragua 
°i the Indians) continues its course west-north-west, turning 
round the group of the mountains of Parime; the other branch 
burning the communication with the Amazon runs into 
Plains, the general slope of which is southward, but of which 
the partial planes incline, in the Cassiquiare, to south-west, 
nr 'd in the basin of the Rio Negro, south-east. A pheno- 
menon so strange in appearance, which I verified ou the 
s pot, merits particular attention; the more especially as it 
may throw some light on analogous facts, which are supposed 
ro have been observed in the interior of Africa. 
The existence of a communication of the .Orinoco with the 
Amazon by the Rio Negro, and a bifurcation of the Caqueta, 
5*® believed by Sanson, and rejected by Rather Fritz and by 
J uaeuw : it was marked in the first maps of De l’lsle, but 
?, a, idoned by that celebrated geographer towards the end of 
ms days. Those who had mistaken the mode of this com- 
munication hastened to deny the communication itself. It 
8 111 fact well worthy of remark that, at the time when the 
* Of nine hundred and fifty toises each, or two hundred and fifty 
Nautical leagues. 
