Mr. J. Ivoi'y on the Constitution of the Atmosphere. 245 



Places. 



Divi- 

 dends. 



Divi- I Quo- 

 sors. tients, 



Col clu Geant, Cha- 1 



mouny J 



Montperdu, Bareges 

 Pic d'Eyre, Tarbes 

 Pic de Montaign . . 

 Pic dii Midi, Bareges 



yds. 



2606 



2354 

 2347 

 2244 

 1808 



Puy de Dome, Cler- 

 mont 



Bed at du Bagneres, 

 Tarbes 



Pont du Berges, 

 Clermont .... 



La Barrague, Do. 



1163 



611 



537 



41i 



+ 21-6 



25-0 

 21-3 

 14-5 

 26-7 

 21-9 

 21-3 

 18-5 

 15-9 

 17-8 

 18-9 

 18-4 



21-3 



17-8 

 18-6 

 24-8 

 329 



10-9 



0-3 

 23-6 



+ 4-5 



6-9 



11-0 



' 3-1 



16-4 



8-0 



8-2 



6-0 



2-5 



7-0 



5-8 



5-2 



14-4 



10-8 

 11-7 

 15-2 

 23-4 



8-0 



— 2-9 



+ 21-8 



0-121 



0-111 

 0-109 

 0-108 

 0-084 

 0-085 

 0-085 

 0-086 

 0-087 

 0-086 

 0-086 

 0-086 



0-054 



0-055 

 0-055 

 0-054 

 0-052 



0-029 



0-026 

 0-019 



-026 



-028 

 -016 

 •018 

 -016 

 -022 

 -020 

 -019 

 -022 

 •017 

 •021 

 -020 



•Oil 



•Oil 

 •Oil 

 •014 

 •014 



•005 



•005 



•003 



The inspection of this table shows that the theory agrees 

 with observation in 16 instances out pf 38 ; in 7 instances, 

 the results of observation are considerably above the theory ; 

 and in 15, the differences are not greater than might be ex- 

 pected. The deviations from the theory seem to be acci- 

 dental ; they are indiscriminately in excess and in defect at 

 all heights, and in measuring the same height at different times. 

 The mean of the whole is 5^4, agreeing with 5^ which is the 

 number determined by the theory. 



With I'egard to the quantities found by observation, no ob- 

 jection can be made to the accuracy of the numbers derived 

 from the barometer. But the case is different with regard to 

 the thermometer. That instrument, it is well known, is af- 

 fected in such experiments by many local and accidental causes, 

 which render its determinations irregular and uncertain, but 

 which it would be superfluous to consider here. It is only 



necessary 



