After a stay of ten days at Cuença, Humboldt entered the province of Jaen, surveyed the Marañon as far as the Rio Napo, and with the aid of the astronomical observations he was able to make, supplemented Condamine's map. On the 23rd October, 1802, Humboldt entered Lima, where he successfully observed the transit of Mercury.
After spending a month in that capital he started for Guayaquil, whence he went by sea to Acapulco in Spanish America.
The vast number of notes collected by Humboldt during the year he spent in Mexico, and which led to the publication of his Essay on Spanish America, would, after what we have said of his previous proceedings, be enough to prove, if proof were needed, what a passion he had for knowledge, how indomitable was his energy and how immense his power of work.
