126 M. Boussingaiilt on Air found in the Pores of Snow. 



Saussure's old experiment^ which I had again brought into notice by ve- 

 rifying it among the perpetual snows of the Andes, attracted the attention 

 of natural philosophers. A German observer, M. Bischoff, in a scries of re- 

 searches relative to the physical history of the globe which he carried on 

 during an excursion among the Alps, had an opportunity of again taking 

 up the inquiry. lie triturated hardened snow under water ; the air pro- 

 cured by this means, analyzed in the eudiometer with sulphuret of potas- 

 sium, afibrded only from 10 to 11 in 100 of oxygen. 



Up to this time these researches had been carried on in elevated regions 

 on glaciers; it was of interest, in order to complete them, to examine the 

 air of snow collected near the level of the sea. It was with this view 

 that I made some observations on snow fallen at Paris, in the end of De- 

 cember 1840, and in the beginning of January 1841. On the 20th Decem- 

 ber, I closely pressed snow recently fallen into a receiver, which I placed 

 on the mercurial trough. 



The compressed snow occupied a volume of 287^'^- After melting, the 

 volume of air disengaged was about 109c-c. at the temperature of 4°5, 

 and under a pressure of 0'^-743. 



Let it be 104.8cc- at 0°, and the pressure 0™-76. The volume of water 

 was 200CC. 



The air examined on the 23d December yielded by phosphorus, in the 

 first analysis, 18.6 in 100 of oxygen; in a second, 18.8. 



On 6th January, a receiver, of the capacity of 127''-*^- was filled with 

 compressed snow. After fusion, we obtained 43^<^- of air at the tem- 

 perature of 1°, and under the pressure of 0'^-735. 



Let it be at 0°, and the pressure 0™- .76, 4lc.c .4. 



The volume of water was SO'^-'^- 



The air, analyzed shortly after the fusion of the snow, contained 19 in 

 100 of oxygen. 



Tlius the air disengaged during the fusion of the snow, contains at 

 Paris, cquall}^ as on the Alps and the Andes, considerably less oxygen 

 than air from the atmosphere. May we not then conclude that such is 

 really the composition of the air enclosed in the pores of snow before its 

 fusion ? Unquestionably not ; and on this occasion I shall again bring 

 forward an opinion which I expressed in the account of my ascent of 

 Chimbora^o, while relating the fact confirmatory of Saussure's obser- 

 vation. 



" The eudiometrical result which I obtained is certainly free from all 

 objection, but I believe that new experiments are still necessary to prove 

 clearly that the air which I examined was exactly that which existed in 

 the pores of the snow before melting. In fact, it is necessary to wait till 

 the melting of the snow in order to procure this air ; the gas in the vessel 

 is placed in contact with the scarcely or not at all aerated water which 

 has resulted from this fusion. Now we know, that, in similar circum- 

 stances, the oxygen dissolves 'much more easily in the water than the 

 azote, and that the air with which the water is saturated is richer in oxy- 

 gen than that of the atmosphere. The air remaining in the vessel may 



