736 



In ascending from the coast of Venezuela on 

 the table-land of Bogota, the difference of the 

 diurnal maxima and minima^ (notwithstanding 

 the difference of 1365 toises of height), dimi- 

 nishes only one-fourteenth, and consequently, 

 not in the relation of the barometric heights of 

 the places we compare. The comparison of the 

 same hours on different successive days fur- 

 nishes at Santa Fe de Bogota *, and at Popayan 

 (911 t.), scarcely the difference of three or four 

 millimeters in the space of a whole year. The 

 following tables prove, that a great equality in 



* See Semanario de Bogota, Tom. i, p, 50, 83, 115, 177, 

 216, 255, 290. I calculated for every day the mean 

 height of the barometer, and by the diurnal oscillations 

 the extended mean of the oscillations in whole months $ 

 the results are marked in hundredths of lines of the 

 French foot. M. Caldas announces in an indirect manner 

 {Semanario, Tom. i, p. 55), that the epochas of the limits, or 

 tropical hours, which I published in my Essay on the Geogra^ 

 phy of Plants, are not those which M. Mutis found on the 

 plains of Bogota ; this doubt does not appear to me to be 

 well founded. MM. Boussingault and Rivero have confirm- 

 ed the epocha of the maxima and minima which I had an- 

 nounced j and even M. Mutis, who is accused of not being 

 very communicative, told me, when I shewed him my regis- 

 ters, " that the periods observed at Cumana were nearly con- 

 formable to those resulting from his researches, but that in 

 the hottest days, the maximum was attained at Santa Fe de 

 Bogota, at 8 h in the morning." This latter observation re- 

 calls the difference of the tropical hours remarked in Eu- 

 rope, by MM.Ramond, Marque* Victor, and Billiet, between 

 the hottest and coldest seasons. {See above, p. 719). 



