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tions of degrees are often had only by eftimation, and alfo for 

 local clrcumflances. — A full proof that heat afcends in an arith- 

 metical progreffion. 



Thus in the three feries of obfervations on the temperatures 

 at the top and bottom of Mount Sakve, the difference in the firft 

 was S°, 9, in the fecond g°, in the third io°, 5, here the greatefl 

 deviation is i'',5. 



And in the fixth feries at the Mole the differences were, in the 

 firft 7°,T, in the fecond 5^,8, in the third 7"^, in the fourth 7^' 9, 

 in the fifth 7*^, in the fixth 6°, 6. Here two circumftances de'erve 

 attention ; firft, that in the fecond, third and fourth feries the 

 heat above was conftant, nainely 56'', while the heat below , 

 varied from 61°, 8 to 63^'9. This may be attrbuted to a brifk 

 wind, from the glaciers which reigned above, while the lower 

 flank of the hill was fheltered. The fecond is, that the difference 

 between the heat abvoe and the heat below, with refpedl to 

 Mount Saleve was 9°, and yet betwixt the top and bottom of the 

 Mole it was at moft only 7^9 though the height of Mount Saleve 

 was only 2831 feet and that of the Mole was 4212. This muft 

 certainly proceed from the intervention of fome contingent caufe, 

 the general difference may therefore be often better determined 

 by calculation than by a(5lual obfervation. 



In 



