240 CATARACTS OF THE ORINOCO. 



know of the course of the Eio Branco, which flows from 

 north to south through the basin of the Upper Orinoco ; 

 while that river itself, in this part of its course, pursues 

 for the most part an East and West direction. Prom poli- 

 tical reasons, the Brazilians, since the beginning of the present 

 century, have testified a lively interest in the extensive plains 

 east of the Rio Branco. See the memoir which I drew up at 

 the request of the Portuguese court in 181 7," sur la fixation 

 des limites des Guyanes Prai^aise et Portuguaise" (Schoell, 

 Archives historiques et politiques, ou Eecueil de Pieces 

 officielles, Memoires, &c. T. i. 1818, p. 48-58). Viewing 

 the position of Santa Eosa on the Uraricapara, the course 

 of which appears to have been determined with tolerable 

 accuracy by Portuguese engineers, the sources of the Orinoco 

 cannot be looked for east of the meridian of 65J from 

 Paris, (63.8' W. long, from Greenwich). This being the 

 eastern limit beyond which they cannot be placed, and con- 

 sidering the state of the river at the Eaudal de los Guaha- 

 ribos (above Carlo Chiguire, in the country of the surpris- 

 ingly fair-skinned Guaycas Indians, and 52' East of the great 

 Cerro Duida), it appears to me probable that the upper part 

 of the Orinoco does not really extend, at the utmost, beyond 

 the meridian of 66 from Paris (64.08' W. from Green- 

 wich.) This point is according to my combinations 4. 12 

 West of the little lake of Amucu, which was reached by Sir 

 Eobert Schomburgk. 



I next subjoin the conjectures of that gentleman, having 

 given the earlier ones formed by myself. According to his 

 view, the course of the upper Orinoco to the east of Esme- 



