1835.] IN THE PEUQUENES. 321 



power of the crystals of snow, the groups of these micro- 

 scopical 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 re- 

 marked, 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 coasts 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 appear- 

 ances 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 

 mountainous country, intermediate between the two main 

 ranges, and then took up our quarters for the night. We 

 were now in the republic of Mendoza. The elevation was 

 probably not under 11,000 feet, and the vegetation in con- 

 sequence exceedingly scanty. The root of a small scrubby 

 plant served as fuel, but it made a miserable fire, and the 

 wind was piercingly cold. Being quite tired with my day's 

 work, I made up my bed as quickly as 1 could, and went 

 to sleep. About midnight I observed the sky became 

 suddenly clouded : I awakened the arriero to know if 



' Dr. Gillies in Journal oj Natural and Geographical Science, Aug. 1830. 

 i hia author givca the heights of the Puasea. 



