Abstract
The French astronomer La Condamine, sent to Perú to measure an arc of the meridian in 1736, decided to return to France by way of the River Amazon, mapping the river and collecting observations of all sorts. This intention was over-optimistic and the circumstances of the journey prevented La Condamine from gathering much new information or undertaking the necessary observations to improve existing maps. He published three popular versions of the journey but witheld most of the observations that he did make for a later report which was never written. His journals are now lost, but his aims and achievements can be assessed from contemporary documents and the collation of his three accounts