244; M. J. Ivory on the Constitution of the Atmosplieir. 



In order to form a just idea of the theory we must now com- 

 pare these equations with observation. By combining them 



we get, „ /\ + ar — af 



= (- 



1 +ar 



•) 



As T is the temperature at the earth's surface, and t the 

 temperature lost in ascending, if we put t' = t — t, then t' will 

 be the actual temperature in the atmosphere ; and we shall get 



log- ~ -^ log. 



1 +«T 



r= 5. 



(b) 



Supposing that the centigrade thermometer is used, a will 

 be ^^ and the last formula will become 



log. - ^ log. j^+j7 = ^' 

 which we may apply to the measurements recorded in p. 189 of 

 Ramond's work. Tlie dividends, or the logarithms of — , are 



thex-e found ready calculated, but only to 3 places of figures. 

 The quantities t and t' are also given in separate columns, 

 and from these the divisors must be computed. In this man- 

 ner the following table has been constructed, in which only 

 the first figure of the quotient is set down, as the observations 

 do not comport with a greater degree of accuracy. 



Places. 



Gay-Lussac's ascent 



Chimborazo 



Montblanc, Geneva 



Pic de Teneriffe . . 



Montblanc, Cha- ^ 



mouny ^ 



vcls. 



7630 + 

 6i27 

 4782 



4077 

 4070 



Etna 



Montperdu, Tarbes 

 Col du Geant, Geneva 



Maladette 



Pic du Midi, Tarbes 



3540 

 34081 

 3346 

 3174 

 2858 



30-8 

 25-3 

 28-3 

 27-6 

 24-9 



23-0 



25-0 

 23-1 

 25-6 

 24-9 

 20-8 

 27-5 

 19-6 

 22-5 

 23-5 

 18-8 

 19-1 

 14-8 



+ 



9-5 

 1-6 

 2-9 

 1-6 



8-4 



Divi- 

 dends. 



- 2-9 



+ 



1-6 

 4-4 

 6-9 

 4-5 

 3-4 



11-6 

 8-6 

 8-1 



10-4 

 8-1 

 4-0 

 4-3 



0-363 

 0-304 

 0-229 

 0-229 

 0-190 



0-197 



0-196 

 0-172 

 0-155 

 0-153 

 0-150 

 0-131 

 0-133 

 0-135 

 0-133 

 0-135 

 0-136 

 0-134 



Divi- IQuo- 

 sors. tients. 



•0631 6 



•042 7 



-049; 5 



•046 5 



-026 7 



-041 5 



•042 

 •029 

 •029 

 •032 

 -027 

 -024 

 •017 

 -022 



5 

 6 

 5 

 5 

 5 



5h 



8 



6 



-020 6L 



-on! 8 



-023 6 



-016 8 



