86^ Letter from M» A, Humboldt 



During this journey, which lasted a year, I determined 

 51 points of South America, in which I observed the latitudes 

 and longitudes : the former deduced, for the most part, from 

 the meridian altitude of two stars at least ; and the latter, 

 either from the distances of the moon from the sun and stars, 

 or from the time-keeper and horary angles. I am now em- 

 ployed in constructing a map of the country throiigh which 

 I have travelled ; and as my observations fill up the vacuum 

 found in the maps between Quito and Cayenne, to the north 

 of the river of the Amazons, I flatter myself that they will be 

 interesting to geographers. 



My time-keepers have not given me with exactness, but 

 the differences of meridian between the places of my departure 

 arid the Caraccas, Cumana, and St. Thomas de Nueva-Guay- 

 anna, lat. 8=^ 8' 24", long. 21 of time, east from Cumana. 

 I am very anxious, therefore, on account of my map, to fix 

 the position of these three places in regard to Paris, and by 

 observations purely astronomical. Besides, it is very neces- 

 sary that navigators should be able, at the time of their ar- 

 rival on this coast, to find the longitude of the ports well de- 

 termined, that they may know the state of their chronome- 

 ters; for, except Martinico, Guadaloupe, Portorico, where 

 M. De Churucca observed ; Cayenne, and Quito, there are 

 very few places the longitude of which can be depended on ; 

 especially in Spanish America. Carthagena, according to 

 the Connoissance des Temps, is at 5h. 12' 12". But the 

 three emersions of the satellites, observed by Herrera, all give 

 69*^ 24' 10" west of Cadiz, or 5h. 13' 1 1" to the west of Paris. 



1 observed, with a telescope of Dollond, which magnifies 

 95 times, at Cumana, in lat, 10^ 27' 37 : ' 



The immersion of the second satellite Nov. 7, 1799, at 

 lib. 41' 18" true time. 



Of the second satellite, Sept. 11, at 16 h. 3 TO" true time. 



Of the first satellite, Sept. 25, 1800, at 17h. 10' 21" mean 

 time. 



The emersion of the 4th satellite, Sept. 26, at 17 h. 28' 0" 

 mean time. 



Of the third satellite, Sept. 27, at 16 h. 25' 55" mean time. 



Of the fourth satellite, Sept. 26, at 17 h. 28' 0'' mean time. 



I am 



