496 



published in 1775 and 1778, together with the 

 work of father Caulin, have best made known 

 the labours of the expedition of the boundaries ; 

 for the numerous contradictions, that are found 

 in them, relate to the sources of the Oroonoko 

 and the Rio Branco, and not to the course of 

 the Cassiquiare and the Rio Negro, which they 

 indicate as well as could be required in the 

 absolute want of any astronomical observation. 



Such was the state of the hydrographic dis- 

 coveries in the interior of Guyana, when, a short 

 time before my departure from Europe, a man 

 of science, whose labours have been so useful to 

 the progress of geography, thought fit to make 

 new researches respecting the narrative of Acun- 

 ha, the map of father Samuel Fritz, and the 

 America Meridional of La Cruz Olmedilla. The 

 political state of France had perhaps prevented 

 M. Buache from procuring or examining the 

 works of Caulin and Gili, two missionaries, who 

 resided on the banks of the Oroonoko, when the 

 expedition of the boundaries established the 

 communications, which have been regularly 

 kept up during more than half a century, be- 

 tween the Spanish fort of the Rio Negro and 

 the town of Angostura, by the Cassiquiare and 



them many of his own systematic ideas, constructed in 1778, 

 his Mapo corografieo de la Nueva Andaludu. This map is very 

 often contradictory to Caulin's book, to which it is annexed. 



