Theories and Experiments 227 



not invariable, and, in many cases, it seems independent of the effects 

 caused by the rarefaction of the air. It is observed particularly when 

 abundant snows cover the mountains and the weather is calm. 



Perhaps this is the place to note that de Saussure was relieved 

 of the distress he felt on Mont Blanc when a light north wind arose. 

 In America, the name soroche is given to this meteorological state of 

 the air, which affects the organs of respiration so greatly. Soroche, 

 in the language of the American miners, means pyrites; this name 

 shows plainly enough that this phenomenon was attributed to sub- 

 terranean exhalations. The thing is not impossible, but it is more 

 natural to see in the soroche an effect of the snow. 



The suffocation which I felt several times myself while I was 

 mounting over snow, when it was struck by rays of the sun, made 

 me think that air which was evidently foul might escape from it as 

 an effect of the heat. What supported me in this strange idea was a 

 former experiment of de Saussure, in which he thought he observed 

 that the air which escaped from the pores of the snow contained much 

 less oxygen than the atmosphere. The air subjected to examination 

 had been collected in the interstices of the snow on the col du Geant. 

 Analysis of it was made by Sennebier, by nitrous gas and in compari- 

 son with the air of Geneva. (P. 167.) 



M. Boussingault then repeats the experiment of Sennebier with 

 the snow which he had taken from Chimborazo. Ordinary analysis 

 gave him only 16% of oxygen. But the celebrated chemist him- 

 self declares that objection may "strictly" be made to his method; 

 since the snow had melted in the bottle, the air, in the presence 

 of water only slightly aerated, might have given it part of its 

 oxygen. Evidently that depends upon the quantity of air in pro- 

 portion to the quantity of water, a proportion which is not given 

 in the work from which we quote. 



But later, M. Boussingault, having taken up this question again, 47 

 showed that the apparent lack of oxygen in the air contained in 

 the pores of the snow results from the fact that the oxygen is dis- 

 solved in greater proportion than the nitrogen in the water of 

 fusion. There is nothing left then of his first hypothesis. 



These contradictory results, due to the improvement of methods 

 of chemical analysis, remind us of the different opinions expressed 

 in 1804 and 1837 upon the same subject by the illustrious von Hum- 

 boldt. 



In the letters which he wrote to his brother and Delambre, 

 immediately after his ascents of Antisana and Chimborazo, von 

 Humboldt declared that in his opinion 



The distress, the weakness, and the desire to vomit certainly came 

 as much from the lack oi oxygen in these regions as from the rarity 

 of the air. He had found only 0.20 of oxygen at 3031 fathoms, on 

 Chimborazo. (P. 175.) " 



