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Show 394 PASSAGE OF CORDILLERA. March, 1835. for the puna ; as this vegetable has sometime~ been given in Europe for pectoral complaints, it may possibly be of real service :-for my part, I found nothing so good as the fossil shells! When about halfway up we met a large party w~th se~enty loaded mules. It was interesting to hear the wild cnes of the muleteers and to watch the long string descending; they appeared so diminutive, there being nothing but the bleak mountains with which they could be compared. When near the summit, the wind, as generally happens there, was impetuous and extremely cold. On each side of the ridge we had to pass over broad bands of snow, which perpetually lie there and were now soon to be covered by a fresh layer. Whe~ we reached the crest and looked backwards, a glorious view was presented. The atmosphere resplendently cle~r; the sky an intense blue ; the profound va:lleys ; the wild broken fonns ; the heaps of ruins, piled up during the la~se of ages ; the bright-coloured rocks, contrasted with the qmet mountains of snow ; all these together produced a scene I never could have figured to my imagination. Neither ~lant nor bird, excepting a few condors wheeling around the higher pinnacles, distracted the attention from the inanimate mass. I felt glad I was alone: it was like watching a thunderstorm, or hearing a choru~ of the Messiah in full orchestra. On several of the patches of perpetual snow, I found the Protococcus nivalis, or red snow, so well known from the accounts of Arctic navigators. My attention was called to the circumstance by observing the footseps of the mules stained a pale red, as if their hoofs had been slightly bloody. I at first thought 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 atom-like plants appeared like coarse particles. The snow was coloured only where it had thawed very rapidly, or had been accidentally crushed. A small portion of it rubbed on paper communicated a faint rose tinge, mingled with a little brick red. I placed some of the snow between the leaves of March, 1835. RED SNOW. 395 my pocket-book, and a month afterwards examined with care the pale discoloured patches on the paper. The specimens, when scraped off, were of a spherical form, with a diameter of the thousandth of an inch. The central part consists of a blood-red substance, surrounded by a colourless bark. When living on the snow they are collected in groups, many lying close together; I overlooked, however, the thin couch of gelatinous matter on which they are said to rest.* The dried specimens placed in any fluid, as water, spirits of wine, or dilated sulphuric acid, were acted on in two different ways: sometimes an expansion was caused, at others a contraction. The central part after immersion invariably appeared as a drop of red oily fluid, containing a few most minute granules; and these probably are the germs of new individuals. As I before remarked, the wind on the crest of the Peuquenes is generally impetuous and very cold. It is said to blow steadily from the westward or Pacific side : a circumstance which is likewise mentioned by Dr. Gillies.t As these observations apply chiefly to the summer season (when the passes are frequented), we must consider this wind, as an upper and return current. The Peak of Teneriffe, with a less elevation, and situated in lat. 28°, in like manner falls within the 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 rotation of the world. At Mendoza, on the eastern foot of the Andes, the climate is said to be subject to long calms, and to frequent • Greville's Scottish Cryptogam. Flora, vol. iv., p. 231. t Journal of Natural and Geographical Science, August, 1830. |