159 



nately, the foggy atmosphere of a valley, where 

 the forests yield to the air an enormous quan- 

 tity of water, was unfavourable to astronomical 

 observations. I spent a part of the nights wait- 

 ing to seize the moment when some star was 

 visible between the clouds, near it's passage 

 over the meridian. I often shivered with cold, 

 though the thermometer only sunk to 16°, 

 which is the temperature of the day in our cli- 

 mates towards the end of September. The in- 

 struments remained set up in the court of the 

 Convent for several hours, yet I was almost al- 

 ways disappointed in my expectations. Some 

 good observations of Fomalhaut and of Deneb 

 in the Swan gave 10° 10' 14" for the latitude of 

 Caripe ; which proves, that the position indicat- 

 ed in the maps of Caulin is 18' wrong, and in 

 that of Arrowsmith 14'. 



Observations of corresponding altitudes of 

 the Sun* having given me the true time to 

 about 2", I was enabled to determine with pre- 

 cision, at noon, the magnetic variation. It 

 was, on the 20th of September, 1799, 3° 15' 30" 

 north-east; consequently 0° 58' 15" less than 

 at Cumana. If we attend to the influence of 

 the horary variations, which in these countries 

 do not exceed in general 8', we shall find, that 

 at considerable distances the variation changes 



* See Qbs. Ast. vol. i, p. 100—106, 



