276 



Mr. Lubbock on the Heat of Vapours 



ON THE CONDITIONS OF THE ATMOSPHERE, 

 AND ON THE CALCULATION OF HEIGHTS BY 

 THE BAROMETER. 



The same principles are applicable to the constitution of the 

 atmosphere ; but we are far from possessing such extensive and sa- 

 tisfactory data for testing the accuracy of the formulae. The best 

 observations for this purpose are those of M. Gay Lussac, recorded 

 by M. Biot in the Connaissance des Temps for 1841, in the follow- 

 ing table. 



Table des observations par ordre de hauteurs barometriques. 









Hauteur moyenne 



Hauteurs correspond. J 



Numero des 



Temperatures 



Moyenne des 



du barometre dans 



antes au-dessus de 



observations 



en degres du 



indications des 



l'atmosphere, 



l'Observatoire de 



par ordre de 



thermometre 



deux hygro- 



ramenee a celle d'un 



Paris, calculees par la 



pression. 



centesimal. 



metres. 



barometre a" niveau 

 constant. 



formule barometrique 

 de M. Laplace. 



1 



+30-75 



57°-5 



m 

 0-76568 



m 

 0-00 



2 



12-50 



620 



0-5381 



303201 



- 3 



11-00 



50-0 



0-5143 



341211 



4 



8-50 



37-3 



0-4968 



3691-45 



5 



10-50 



330 



0-4905 



3816-79 



6 



1200 



30-9 



0-4666 



4264-65 



7 



11-00 



29-9 



0-4626 



4327-86 



8 







0-4528 



4511-61 



9 



8-75 



29-4 



0-4528 



4511-61 



10 



8-25 



27-6 



0-4404 



4725-90 



11 



6-50 



27-5 



0-4353 



4808-74 



12 



5-25 



30-1 



0-4229 



5001-85 



13 



1-00 



33-0 



0-4141 



5175-06 



14 



4-25 



27-5 



0-4114 



5267-73 



15 



2-50 



32-7 



0-3985 



5519-16 



16 



000 



35-1 



0-3918 



5631-65 



17 



+ 0-50 



30-2 



0-3901 



5674-85 



18 



- 3-00 



32-4 



0-3717 



6040-70 



19 



- 1-50 



32-1 



0-3696 



6107-19 



20 



- 3-25 



33-9 



0-3670 



6143-79 



21 



- 7-00 



34-5 



0-3339 



6884-14 



22 



- 9-50 





0-3288 



6977-47 



I shall employ the 1st, 5th, and 21st observations for the deter- 

 mination of the constants, and I propose then to calculate with these 

 constants the temperatures corresponding to the intermediate obser- 

 vations. As the pressures are proportional to the heights of the ba- 

 rometer, if the variation of gravity be neglected we may take the 

 heights of the barometer to represent them, and we have 



