178 YIEWS OP NATURE. 



enterprise in inhospitable regions, a passionate love for any 

 department of scientific labour (be it natural history, astro- 

 nomy, hypsometrics, or magnetism), a pure feeling for the 

 enjoyment which nature is capable of imparting, are elements 

 which, when they combine together in one individual, ensure 

 valuable results from a great and important journey." 



I will preface my consideration of the question of the 

 sources of the Orinoco with my own conjectures in relation 

 to the subject. The perilous route travelled in 1739 by the 

 surgeon Nicolas Hortsmann, of Hildesheim; in 1775 by the 

 Spaniard Don Antonio Santos, and his friend Nicolas Rodri- 

 guez; in 1793 by the Lieutenant-Colonel of the 1st Regiment 

 of the Line of Para, Don Francisco Jose Rodriguez Barata ; 

 and (according to manuscript maps, for which I am indebted 

 to the former Portuguese Ambassador in Paris, Chevalier de 

 Brito) by several English and Dutch settlers, who in 1811 

 travelled from Surinam to Para by the portage of the Rupu- 

 nuri and by the Rio Branco; — divides the terra incognita of 

 the Parime into two unequal parts, and serves to mark the 

 position of a very important point in the geography of those 

 regions — viz., the sources of the Orinoco, which it is no 

 longer possible to remove to an indefinite distance towards 

 the east, without intersecting the bed of the Rio Branco, 

 which flows from north to south through the fluvial district of 

 the Upper Orinoco ; while this portion of the great river itself 

 pursues for the most part a direction from east to west. The 

 Brazilians, since the beginning of the present century, have 

 from political motives manifested a vivid interest in the ex- 

 tensive plains east of the Rio Branco.* Owing to the 

 position of Santa Rosa on the Uraricapara, whose course ap- 

 pears to have been pretty accurately determined by Portu- 

 guese engineers, the sources of the Orinoco cannot be situated 

 east of the meridian of 63° 8' west long. This is the eastern 

 limit beyond which they cannot be placed, and taking into con- 

 sideration the state of the river at the Raudal de los Gua- 

 haribos (above Cano Chiguire, in the country of the strikingly 

 fair- skinned Guaycas Indians, and 52' east of the great Cerro 



* See the Memoir which I drew up at the request of the Portuguese 

 Government, in 1817, " Snr la fixation des limites des Guyanes Fran- 

 faise ct Portuguaise." Schoell, Archives historiques et politiques. ou 

 JRecueil de Pieces officielles, Memoires, d-c. t. i. 1818, pp. 48 — 58. 



