XV 
RED SNOW 
345 
watching a thunderstorm, or hearing in full orchestra a chorus 
of the Messiah. 
On several patches of the snow I found the Protococcus 
nivalis, or red snow, so well known from the accounts of Arctic 
navigators. My attention was called to it by observing the foot¬ 
steps of the mules stained a pale red, as if their hoofs had been 
slightly bloody. I at first thought that it was owing to dust 
blown from the surrounding mountains of red porphyry ; for 
from the magnifying power of the crystals of snow, the groups 
of these microscopical plants appeared like coarse particles. 
The snow was coloured only where it had thawed very rapidly, 
or had been accidentally crushed. A little rubbed on paper 
gave it a faint rose tinge mingled with a little brick-red. I 
afterwards scraped some off the paper, and found that it 
consisted of groups of little spheres in colourless cases, each the 
thousandth part of an inch in diameter. 
The wind on the crest of the Peuquenes, as just remarked, 
is generally impetuous and very cold ; it is said 1 to blow 
steadily from the westward or Pacific side. As the observations 
have been chiefly made in summer, this wind must be an upper 
and return current. The Peak of Teneriffe, with a less elevation, 
and situated in lat. 28°, in like manner falls within an upper 
return stream. At first it appears rather surprising that the 
trade-wind along the northern parts of Chile and on the coast 
of Peru should blow in so very southerly a direction as it 
does ; but when we reflect that the Cordillera, running in a 
north and south line, intercepts, like a great wall, the entire 
depth of the lower atmospheric current, we can easily see that 
the trade-wind must be drawn northward, following the line 
of mountains, towards the equatorial regions, and thus lose 
part of that easterly movement which it otherwise would have 
gained from the earth’s rotation. At Mendoza, on the eastern 
foot of the Andes, the climate is said to be subject to long 
calms, and to frequent though false appearances of gathering 
rain-storms : we may imagine that the wind, which coming 
from the eastward is thus banked up by the line of mountains, 
would become stagnant and irregular in its movements. 
Having crossed the Peuquenes, we descended into a moun- 
1 Dr. Gillies in Journ. of Nat. and Geograph. Science , Aug. 1830. This author 
gives the heights of the Passes. 
