INTRODUCTION. 87 



have their sources. This ehain forms, therefore, in 

 Guiana, the separation of waters between the basins 

 of the rivers which flow northward into the Atlan- 

 tic and those which enter the largest river of the 

 known world, — the Amazon. 



This extensive territory is intersected by numer- 

 ous rivers and streams ; I mention only the Amazon, 

 the Orinoco, the Essequibo, with their numerous 

 tributaries. A short portage of about seven to eight 

 hundred yards separates the basin of the Amazon 

 from that of the Essequibo ; and by traversing this 

 portage during the rainy season, the river Amazon 

 and the upper Orinoco may be entirely reached 

 from Demerara by inland navigation. So great is 

 the facility for water communication in that part of 

 South America, that by traversing the portage above 

 alluded to, and by constructing a canal of about 

 three miles' length, between the Guapore, a branch 

 of the Marmore and Madeira, and the Rio Aqua- 

 pehi, a branch of the Jaura and Paraguay, an inland 

 navigation would be opened between Demerara 

 and Buenos Ayres over an extent of forty-two de- 

 grees of latitude. The river Napo offers communi- 

 cation with Quito, the Ucayali with Cuzco, the 

 Huallaga with Lima. Ascending the Rio Negro, 

 and entering the Orinoco by the natural canal the 

 Cassiquiare, its tributary the Meta offers an unin- 

 terrupted navigation to New Grenada, and within 

 eight miles of Santa Fe de Bogota. 



Few countries on the surface of the globe can be 



