313 



partial observations. The perfect concord- 

 ance that I observed on the spot, between the 

 satellites of Jupiter and the chronometrical re- 

 sults, inspired me with great confidence in the 

 going of the time-keeper by Louis Berthoud, 

 whenever it was not exposed to the violent jolt- 

 ing of the mules # . 



The days which preceded and followed the 

 eclipse of the Sun displayed very remarkable 

 atmospherical phenomena. It was what is 

 called in those countries the season of winter ; 

 that is, of clouds and small electrical showers. 

 From the 10th of October to the 3d of Novem- 

 ber, at nightfall, a reddish vapour arose in the 

 horizon, and covered in a few minutes, with a 

 thicker or thinner veil, the azure vault of the 

 sky. Saussure's hygrometer f , far from indi- 



* The following are the results of the whole of the obser- 

 vations^ the longitude made at Cumana in 1799 and 1800. 

 By the timekeeper as regulated at Corunna 4h 26 7 4" 

 By 10 immersions and emersions of the 



Satellites - - - - - - 4 26 6 



By lunar distances - - - - 4 25 32 



By the eclipse of the sun - - - - 4 25 55 



Longitude of Cumana - - - - 4 25 54 

 See my Astronomical Obs., Vol. i, p. 64 — 86. 

 f It must be remembered, that in this latitude, at times 

 when it never rains, Saussure's hygrometer remains commonly 

 between 85° and 90°., the temperature being from 25° to 30°. 

 In Europe in the month of August, with the same degree of 



