754 



between the greatness of the horary oscilla- 

 tions, and the seasons f % but this connection 

 is manifest at Paris by the mean of 72 months. 

 The extent of the oscillations from 9 h in the 

 morning* till 3 h in the afternoon, was found, in 

 the months of November, December, and Jan- 

 uary, to be only 0.54 mm ; and in the three fol- 

 lowing months, \ 1.05 mm . The same difference 

 is manifested in the observations made by M. 

 Kamond, at Clermont-Ferrand. M. Billiet 

 found in 1822 and 1823, the extent of the 

 horary variations at Chambery (lat. 45° 34') to 

 be in winter, 0.90 ram and 0.82 mra ; and at the 

 same epocha, at Paris, 0.69 mm and 0.73 lum . On 

 the contrary, in the summer months of 1822, 

 and 1823, these quantities attained at Cham- 

 bery, 1.29 mra and 1.00 mm ; and at Paris, 0.90 mm 

 and 0.75 mm . The two whole years which we take 

 for an example, give;}; for Chambery, 1.06 mm ; 



* Bibl. univ., Tom. xx, p. 246, 



f Laplace, Essaiphil. sur les probabilites, 1825, p. 122. 



% These differences, which we find in reducing all the ob- 

 servations of Paris, Chambery, and Toulouse, to the tem- 

 perature of zero, are so much the more remarkable as 

 the latitude differs only 5°, and the accidental variations 

 observed at the same hours at Chambery, are | less than at 

 Paris. M. Marcel de Serres asserts that he found for one 

 year only (1819), reducing the heights to the temperature of 

 zero, the extent of the oscillations at Montpellier, 1.67"™. 

 M. Arago obtained in the same year, G.33 mm , for Paris. 

 Bullet, dela Soc.d'Agr, du Herault. Sept. 1824. 



