1835.] RED SNOW, 323 
gators. My attention was called to it, by observing the footsteps 
of the mules stained a pale red, as if their hoofs had been slightly 
bloody. Tat 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* 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 
iaust 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 irregu- 
lar in its movements. 
Having crossed the Peuquenes, we descended into a mountain- 
ous country, intermediate between the two main ranges, and then 
took up our quarters for the night. We were now in the re- 
public of Mendoza. The elevation was probably not under 
11,000 feet, and. the vegetation in consequence exceedingly 
* Dr. Gillies in Journ. of Nat. and Geograph. Science, Aug. 1830. This 
author gives the heights of the Passes. 
