M. Boussingault on Air found in the Fores of Snow. 127 



therefore be less rich in oxygen, although in reality the whole air con- 

 tained in the snow was of the ordinary composition."* 



Such is the true explanation of the small proportion of oxygen de- 

 tected in air emanating from snow during its fusion ; this will be de- 

 monstrated by the experiments already cited, when I shall have com- 

 pleted them by the following observations. 



On the 20th December and 6th January, independently of the experi- 

 ments already related, I made arrangements for others on a larger scale, 

 in order to obtain a sufficiency of snow-water to enable me to extract the 

 air and analyze it. I shall confine myself to an account of one of these 

 experiments. 



From 260^-^' of water produced by the melting of snow, wc obtained 

 by continued boiling 12'^'^- of air at the temperature of 3°.2, pressure 

 0^- 751 . Let it be 1 l^-c- .62 at 0'' and pressure 0™. 76. 



This air, analyzed by phosphorus, contained 32 in 100 of oxygen, a 

 result wliich entirely agrees with those obtained by MM. de Humboldt 

 and Gay-Lussac ;t they found that air derived from 



Distilled aerated water, contains oxygen, 32.9 in 100 



Water of the Seine, . . . 81.9 



Rain water, . . . . 31.0 ... 



By referring again to the preceding experiments, and taking into ac- 

 count the air enclosed in the volumes of water obtained, we perceive 

 that, although the air disengaged from the snow contained only 18.7 and 

 19 of oxygen, the totality of this air, that is to say, the air measured and 

 the air dissolved, the volume of which has been disregarded, contained, 

 as nearly as possible, 20 in 100 of oxygen, a number approaching very 

 nearly to that adopted to represent the oxygen of the atmosphere. 



There is, besides this, a much more direct means of ascertaining the 

 real composition of the air of snow. This consists in filling a glass vessel 

 with snow, and conducting the operation as if engaged in extracting air 

 from a liquid. The following is an example, being an experiment made 

 on the 6th January : — 



350'^-^- of snow afforded 11 ^-^-.S of air, at the temperature of 3".3, and 

 under the pressure of 0'"- 740. 



Analyzed by phosphorus, this air gave in the 100 — 



In the first analysis, . . . 20.3 



In the second, .... 21.0 



This is very nearly the quantity of oxygen found in the air of the 

 atmosphere on the same day, and by the same means. In my opinion, 

 it was of considerable importance to determine the real composition of 

 the air contained in the interstices of snow, for if it had been proved that 

 there was a smaller quantity of oxygen, the fact, from the considerations 

 we are about to mention, would have gone directly to support the hypo- 



♦ Annales de Chimie et de Physique, tome Iviii. p. 150, and Jameson's PhUoso- 

 phical Journal, vol. xix. p. 101. 

 t Memoir on the Eudiometer, Jov/mal de Phynque, 



