725 



M.Boussingault, in transmitting to me for the 

 Academy of Sciences, the observations of the 

 horary variations made during a whole year, 

 conjointly with M. Rivero, at Santa Fe de Bo- 

 gota, speaks as follows of the limit-hours : "It 

 is a fact established by your labors, and verified 

 by ours, that the mercury between the tropics 

 attains its maximum between 8 h and 10 h in the 

 morning ; then descends till near 4 h , and is at 

 the minimum between 3 h and 5 h in the after- 

 noon ; that it then ascends till ll h at night, 

 without reaching, however, the same height 

 at which it was at 9 h in the morning ; and 

 finally, re-descends till 4 h in the morning, 

 without going as low as it was at 4 h in the af- 

 ternoon. In consulting the whole of our obser- 

 vations made atSanta-Fe de Bogota, in 1823 and 

 1824, (and there are more than 1200 of them),we 

 remark that the greatest height observed, took 

 place July 16th 1824, at 9 h in the morning : it 

 was reduced to the temperature of zero, of 

 0.5b388 m . The smallest height was observed 

 Nov. 5th, 1823, at 4 h in the evening : it was 

 0.55768 m . During whole months the barome- 

 tric heights observed at the same hours, at 

 Bogota, do not differ 0.4 ra ; and the mercury in 

 the space of a whole year, only oscillated at the 

 epocha of the maximum of 9 h in the morning, 

 between 0.55928 m , and 0.56388 m ; and at the 

 epocha of the minimum of 4 h in the evening, 



