[ 36o ] 



All thefe determinations muft neceffariiy vary according to the 

 feafons, and according as the heights are computed perpendicularly 

 to fea or land, nay even according to the different fituations of 

 the land and its different temperatures. 



Thus, in the German or Northern fide of Swifferland, its height 

 is only 8312 feet, but on the Southern or Italian fide, not above 

 ninety miles diftant, it reaches 8952 feet*. The height of Col de 

 Geant furpafTes the height of this line, and yet the thermometer 

 rofe lo® Fahr. about two o'clockf, but at night it fell beneath that 

 line. 



These variations render the lower line of congelation an unfit 

 limit towards which the diminution of heat fhould be computed, 

 and hence I fix the limit on the upper line of congelation, whofe 

 variations are, refpedively, at leaft in fummer and ferene weather, 

 much lefs confiderable. 



Table 



* Bertrand, Renouvellementdes terres, 251. 

 f Sauffiire, Voy. § 2051. 



