FROM QUITO TO MEXICO. 325 



that time but seldom visited by Europeans. This rare privilege 

 promised shortly to be mine ; for the object of my present 

 journey was not so much to observe the transit of Mercury as 

 to fulfil an engagement made with Captain Baudin, on my de- 

 parture from Paris, to join his expedition round the world, 

 upon which he was to start as soon as the French Eepublic was 

 in a position to furnish the sum of money already destined for 

 that object.' 1 



After visiting the mines of Grualgayoc, Humboldt crossed for 

 the fourth time the chain of the Andes, and passing through 

 Quercotillo and Cascas, reached the shore of the Pacific Ocean 

 at Truxillo. Here he remained a few days in order to obtain 

 the latitude and longitude of the town, and to test the going of 

 his chronometer, and then set out for Lima, travelling along the 

 coast, over a portion of the great plain of Peru, which stretches 

 to the south as far as Pisco and Yea. 



The geographical position of Lima had up to that time been 

 very imperfectly ascertained. For its more accurate determina- 

 tion Humboldt compared the longitude given by his chrono- 

 meter with the results obtained by a series of lunar altitudes. 

 The transit of Mercury was successfully observed at Callao, the 

 port of Lima, on November 9, 1802. 



While at Callao, Humboldt's attention was first directed to 

 the valuable properties of guano as manure. Through him its 

 efficacy was first tested in Europe, where its introduction for 

 agricultural purposes may be ascribed to his writings, in which 

 he discusses its formation, and describes its profusion and suc- 

 cessful employment upon the sterile coasts of Peru. 2 



On December 5, 1802, Humboldt embarked for Guayaquil, 

 and landed at that port on January 9, 1803. During the 

 voyage he rendered valuable service to navigation by deter- 

 mining the exact position of several places along the coast 

 the island of Pelado, Points Aguya, Pariria, Mala, &c. His 

 stay at Guayaquil lasted six weeks, during which he made an 

 excursion to the almost impenetrable forests of Babajos, and 



1 < Ansichten der Natur,' vol. ii. p. 365. 



2 Wilhelm Cohn-Martiniquefelde, ' Alexander von Humboldt und die 

 Landwirthschatt/ in Fruhling's * Neue landwirthschaftliche Zeitung,' 19th 

 annual issue, Part III. 



