234 PORTILLO PASS. [CHAP. xv. 



transverse breaks which connect the longitudinal channels, are very 

 strong, so that in one transverse channel even a small vessel under sail 

 was whirled round and round. 



About noon we began the tedious ascent of the Peuquenes ridge, 

 and then for the first time experienced some little difficulty in out 

 respiration. The mules would halt every fifty yards, and after resting 

 for a few seconds the poor willing animals started of their own accord 

 again. The short breathing from the rarefied atmosphere is called by 

 the Chilenos " puna ; " and they have most ridiculous notions concerning 

 its origin. Some say, " all the waters here have puna ; " others that, 

 " where there is snow there is puna ; " and this no doubt is true. 

 The only sensation I experienced was a slight tightness across the 

 head and chest, like that felt on leaving a warm room and running 

 quickly in frosty weather, There was some imagination even in this ; 

 for upon finding fossil shells on the highest ridge, I entirely forgot the 

 puna in my delight. Certainly the exertion of walking was extremely 

 great, and the respiration became deep and laborious : I am told that 

 in Potosi (about 13,000 feet above the sea) strangers do not become 

 thoroughly accustomed to the atmosphere for an entire year. The 

 inhabitants all recommend onions for the puna ; as this vegetable has 

 sometimes 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 with seventy loaded 

 mules. It was interesting to hear the wild cries of the muleteers, and 

 to watch the long descending string of the animals ; 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, was impetuous and extremely cold. On each side 

 of the ridge we had to pass over broad bands of perpetual snow, which 

 were now soon to be covered by a fresh layer. When we reached the 

 crest and looked backwards, a glorious view was presented. The 

 atmosphere resplendently clear ; the sky an intense blue : the pro- 

 found valleys; the wild broken forms; the heaps of ruins, piled up 

 during the lapse of ages ; the bright-coloured rocks, contrasted with 

 the quiet mountains of snow ; all these together produced a scene no 

 one could have imagined. Neither plant nor bird, excepting a few 

 condors wheeling around the higher pinnacles, distracted my attention 

 from the inanimate mass. I felt glad that I was alone: it was like 

 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 footsteps 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. 



