726 



between 0.55768*, and 0.56I85 m . These are 

 the extreme oscillations." M. Boussingault 

 found the tides at Bogota, from the 4th to the 

 5th of January, 1824, as follows: (16 h ) 

 560,70'™; (17 h ) 561.00; (21 h ) 562.75; (22 h ) 

 562.75 ; (23 h ) 562.65 ; (noon) 562.30 ; (l h ) 

 561.60 ; (2*) 561.25 ; (3 h ) 560.80; (4*) 560.50; 

 (5*0 560.65; (6 h ) 561.10; (7 h ) 561.55; (9 h ) 

 562.60; (10 h ) 562.75. 



M. Arago has submitted to a new examina- 

 tion the observations made by MM. Boussin- 

 gault and Rivero in November 1822, at the 

 port of La Guayra, almost in the meridian of 

 Caraccas. In reducing these observations to 

 zero of the centigrade thermometer, he finds 

 that from the 23rd November to the 7th De- 

 cember, the mean of 9 h in the morning was 

 equal to 760.05 mm ; that of 10 h , to 760.03 mm ; 

 that of 4 h in the evening, to 757.44 mm ; and that 

 consequently, the mean diurnal variation was 

 2,44mm Yhe partial differences of the days 

 varied from 2.04 mm to 2.92 mm . In comparing 

 all the absolute heights of the barometer ob- 

 served at La Guayra at the same hour on dif- 

 ferent days, differences are remarked that rise 

 to 2.10 mm . M. Arago * thinks, from the ob- 

 servations of MM. Boussingault and Rivero, 

 that, at the equator as in the temperate climates, 



* Annates de chimie et de physique, Tom. xxv, p. 428. 



