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direction is from west to east. In the first part 

 of it's course, where the river flows from east 

 to west, it forms that celebrated bifurcation so 

 often disputed by geographers, of which I was 

 the first enabled to determine the situation by 

 astronomical observations. One arm of the 

 Oroonoko, the Cassiquiare, running from north 

 to south, falls into the Guainia, or Rio Negro, 

 which, in it's turn, joins the Maragnon, or river 

 of Amazons. The most natural way therefore, 

 to go from Angostura to Grand Para, would 

 be to ascend the Oroonoko as far as Esmeralda, 

 and then to go down the Cassiquiare, the Rio 

 Negro, and the Amazon ; but, as the Rio Negro 

 in the upper part of it's course approaches very 

 near the sources of some rivers, that fall into 

 the Oroonoko near San Fernando de Atabapo 

 (where the Oroonoko abruptly changes it's di- 

 rection from east to west, to take that from 

 south to north), the ascending that part of the 

 river between San Fernando and Esmeralda, 

 in order to reach the Rio Negro, may be avoid- 

 ed. Leaving the Oroonoko near the mission of 

 San Fernando, you go up the assemblage of little 

 black rivers (the Atabapo, the Temi, and the 

 Tuamini), and the boats are carried across an 

 isthmus six thousand toises broad, to the banks 

 of a stream (the Canno Pimichin), which flows 

 into the Rio Negro. This course, which we 

 took, and which has been frequented more 



