1835.] Ascent of Chimborazo. 255 



submitted to examination was collected from the interstices 

 of snow found in a large crevice. The analysis was made by 

 Sennebier, by means of nitrous gas, and was compared with 

 one of the air of Geneva. The following are the results, 

 in the words of Saussure : *' At Geneva, a mixture of equal 

 parts of atmospheric air and nitrous gas, gave twice 1*00. 

 The air from the snow, determined in the same way, gave, 

 by one experiment, 1*85, by another, 1*86. This trial, which 

 appears to indicate great impurity in this air, would have 

 required experiments to determine the nature 6f the gas 

 which occupied the place of the oxygen.''^ 



I had long wished to repeat the experiment of Sennebier ; 

 for, supposing that it was correct ; admitting that the air 

 contained in the snow of the mountains possesses less oxygen 

 than common air, we can conceive how this impure air, 

 disengaged by the heat of the sun, may, by expanding in 

 the atmosphere, occasion inconvenience to those who are 

 obliged to respire it. It was with this view that I filled a 

 bottle with snow at the station of Chillapullu. 



When we arrived at the farm of Chimborazo the snow 

 was completely fused. The water which resulted from it, 

 occupied about an eighth of the capacity of the bottle. 

 Seven-eighths were, therefore, filled with air, proceeding, 

 in a great measure, from the snow : I say, in a great mea- 

 sure, because, in filling the bottle with snow, it was impos- 

 sible to prevent the introduction of a notable quantity of 

 common air. I analyzed the air from the snow of Chilla- 

 pullu, with much care, by means of a phosphorus eudio- 

 meter : 82 parts left 68 of azote. Thus, 14 parts of oxygen 

 were absorbed. This air, therefore, contained 16 per cent, 

 of oxygen. 



However, if we consider that the bottle, independently 

 of the air from the snow, contained also atmospheric air, 

 we shall be disposed to consider this experiment as a confir- 

 mation of the result of Saussure. And the diflticulty of 

 breathing upon the ice, when the sun shines upon it, the 

 soroche of the high mountains of Peru will be explained to 

 a certain extent, by admitting that the air which surrounds 

 a glacier is sensibly less pure in the vicinity of the snaw 

 than that of the atmosphere. The eudiometrical result 



* Saussure Voyage dans les Alps, vii. 472. 



