The Real Expedición de Límites al Orinoco (1754-1761)

A boundary commission sent to fix the line with Portugal surveyed the Orinoco instead. Its cosmographer's observations of 1756 are the latitudes a Franciscan of the expedition printed in 1779; its boats passed rapids a famous Jesuit had called impassable, and it left forts, portages and towns on the Río Negro. The same book records that the people gathered into those towns fled to the forest in a single night.