NAVIGATION Of THI KAPIDS. 
26 i 
placed under them to serve as rollers, they are drawn as far 
as the place where the river again becomes navigable. This 
operation is seldom necessary when the water is high, W ® 
cannot speak of the cataracts of the Orinoco without recal- 
ling to mind the manner heretofore employed for descending 
the cataracts of the Nile, of which Seneca has left us » 
description probably more poetical than accurate. I shall 
cite the passage, which traces with fidelity what may he seen 
every day at Atures, Maypures, and in some pongos of the 
Amazon. “ Two men embark in a small boat ; one steers, 
and the other empties it as it fills with water. Long buffeted 
by the rapids, the whirlpools, and the contrary currents, 
they pass through the narrowest channels, avoid the shoals, 
and rush down the whole river, guiding the course of the 
boat in its accelerated fad.” * 
In hydrographic descriptions of countries, the vague 
names of cataracts, cascades, falls, and rapids, t denoting 
those tumultuous movements of water which arise fro>» 
very different circumstances, are generally confounded with 
one another. Sometimes a whole river precipitating 
itself from a great height, and by one single fall, renders 
navigation impossible. Such is the majestic fall of the 
Rio Tequendama, which I have represented in my “ Views 
of the Cordilleras;’ such are the falls of Niagara an 
of the Rhine, much less remarkable for their elevation, 
than for the mass of water they contain. Sometimes stonj 
dikes of small height succeed each other at great distance®, 
and form distinct falls ; such are the caclioeiras of the 
Negro and the litio Madeira, the saltos of thc^ Hio Cau^* 1 ’ 
and the greater part of the pont/ox that are found in 1 1 
Upper Maraiion, from the confluence of the Chinchipe 
the village of San Borja. The highest and most formidao 
of these pongos, which are descended on rafts, that ' _ 
Mayasi, is however only three feet in height. Sometim^ 
small rocky dikes are so near each other that they toi'i 1 ^ 
for several miles an uninterrupted succession of cascade 
and whirlpools ( chorros and remolinos) ; these are proper . 
* Nat. Quaist., lib. iv, cap. 2. (edit. Elzev., tom. ii, p, 609.) 
+ The corresponding terms in use amone the people of South A 
re saltos, chorros, pongos, cachociras, and raudales. 
