M. Boussingault on Air found in the Fores of Snow, 125 



That the decomposition took place under unequal influences, 

 in consequence of which sometimes more, sometimes less, of 

 the silicic acid, was left undissolved ; 2. The dissolving medium 

 could deposit silica while the potash was taken up ; and, 3. 

 The kaolin could be formed from other minerals besides fel- 

 spar. He considers this last supposition improbable, but the 

 second very probable. In the mean while the first seems the 

 most probable of all ; it requires only one condition to explain 

 the dissimilarity of the result, viz. a greater or smaller amount 

 of carbonic acid in the water, by which sometimes more, some- 

 times less, silica would be separated from the alkali.* 



On the Composition of the Air found in the Pores of Snow, 

 By M. Boussingault. 



During his staj^ on the Col du Geant, Saussure, upon examining the air 

 enclosed in the pores of snow, thought that it contained considerably less 

 oxygen than the air of the atmosphere. The following is the account he 

 has left us. 



'' We thought, but a little too late, of collecting the air enclosed in the 

 Interstices of the snow, and we carried it to M. Sennebier for the purpose 

 of analyzing it. At Geneva, a mixture of equal parts of atmospheric air 

 and nitrous gas afforded him, twice consecutively, 1.01. The air of snow, 

 tested in the same manner, gave him on one occasion 1.85, and on another 

 1.86. This experiment, which appears to indicate a great degree of im- 

 purity in this air, would have required trials to ascertain the nature of the 

 gas which occupies the place of oxygen in the air in question."f 



At the time when the beautiful investigations of Saussure were under- 

 taken, the eudiometer had madtj little progress ; but, notwithstanding its 

 imperfection, it was difficult to admit that such observers as Saussure and 

 Sennebier had been deceived in regard to the difference observed in the 

 composition of two gases, analyzed by the same means and in the same 

 conditions. It was this consideration which induced me to repeat Saus- 

 sure's experiment when I happened to be among the glaciers of America. 

 In the first attempt made by Colonel Hall and myself to ascend Chim- 

 bora9o,;}; on the side looking to ChlUapullu, we fell in with snow so loose 

 and deep that it was impossible, notwithstanding our utmost efforts, to 

 get beyond the height of 6115 metres. It was at this point that I filled 

 a jar with snow, sealing it hermetically. When we reached the hut where 

 we were to pass the night, the snow was completely melted; the water 

 produced by Its fusion occupied \ of the vessel. Having analj'zed the 

 air In the vessel by means of phosphorus, I ascertained that it contaiHed 

 only 16 or 17 in the 100 of oxygen. 



* From Berzelius's Jahres-Berxcht^ Yittr Jahrgang. 



t Saussure, tome viL p. 472. 



X See Jameson's Philosophical Journal, vol. xix. p. 88. 



