Note 18 — Chapter XIII

I have reason to suspect that the snow-line in Chile is subject to extreme variation. I was told, that during one remarkably dry and long summer, all the snow disappeared from Aconcagua. Not being at the time aware of the extraordinary elevation of this mountain (23,000), I did not closely cross-question my informers. It must be remembered that even in ordinary summers the sky is generally cloudless for six or seven months, that no fresh snow falls, and that the atmosphere is excessively dry. It may be asked whether vast quantities of snow would not, under this condition of circumstances, be evaporated? so that it might be possible that all the snow should disappear from a mountain without the temperature having risen above the freezing point. Mr. Miers (vol. i., p. 384) says he passed the Cordillera by the Cumbre Pass on May 30th, 1819, “when not the smallest vestige of snow was observable in any part of the Andes.” Yet Aconcagua is in full view in the approach to this pass. Mr. Miers, in another part (p. 383), makes a general assertion to the same effect.