Ib3b.| RED SNOW. ' 325 



gators. My attention was called to it. by observing the footsteps 

 if the mules stained a pale red, as if their hoofs had been slightly 

 jloody. 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 oif 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 

 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 Meudoza, 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 undei 

 11,000 feet, and the vegetation in consequence exceedingly 



* Dr. Gillies in Jouru. of Nat. and Geograph. Science, Aug. 1830. This 

 author gives the heights of the Passes. 



Y 2 



