FROM SANTIAGO TO MENDOZA BY THE USPALLATA PASS. 7 



great magnitude until we commenced to ascend the Cuesta de la Cumbre, where in one place 

 we had to cross a field a third of a mile wide. This was already undermined by the melting 

 snow from the more exposed places above, and our mules frequently sank into it so deep as to 

 make it very difficult to extricate them. It was necessary for us to dismount and feel our way 

 on foot, and in this exercise I experienced, for the first time, what is called the puna— a diffi- 

 culty in filling the lungs in consequence of the rarity of the atmosphere. This is frequently 

 accompanied by partial blindness and vomiting. My attack, however, was very slight, merely 

 causing a necessity to halt and pant every fifty yards or so. 



We found in the snow a stray mule, belonging to a train that had passed over early in the 

 morning. He was imable to get out, and would probably have died soon ; at all events, two or 

 three condors appeared to think so, as they were hovering around him in close circles, evidently 

 expecting a feast. We extricated him and carried him along with ours. 



The casucha where we stopped for work is situated on a little knoll which was sticking out 

 of the snow, like an island. It is a sufficiently inappropriate place for magnetic observations, 

 as the cold wind whistles around the corners with such violence as to jar the instruments, and 

 render it necessary to make duplicate measures. There was no better place to be found, how- 

 ever, and I therefore set to work. The mules were unladen and sent down in charge of the 

 peon to where pasturage could be found ; the arriero and myself remaining at the casucha. 

 As much of the work as possible was completed before dark, but enough remained to detain us 

 till next day. 



I have rarely passed so uncomfortable a night, nor one, at the same time, more impressive. 

 My face and hands were blistered by the sun and chapped by the cold winds to such an extent 

 as to produce fever, and I found it impossible to sleep. Nor did the arriero appear to be any 

 better ofi'. He was troubled with what he called the "whiffles," which he attributed to drink- 

 ing a cup of tea. What the disease is I do not know, but it kept him awake ; and so we both 

 got up, made a fire of the tent-pole, and passed the greater part of the night in conversation. 

 I volxinteered two or three stories to pass away the time ; one of which was so very good that 

 I am sorry it cannot be given here. At least Joaquin — the arriero — thought so, for he did not 

 recover from it for a long time. Occasionally, as we were riding along the next day, I would 

 see him check his mule and wait for me to overtake him, when he would ask me a question 

 bearing on the pith of the story; but, without waiting for an answer, would trot on ahead 

 again, whickering to himself with great satisfactiom 



From time to time our conversation would be interrupted by hearing hoarse shouts on the 

 eastern side of the mountain^ and pretty soon we would see a long line of cattle coming over 

 the summit. On they would come at a slashing pace, followed by ten or a dozen swarthy looking 

 centaurs, shouting and stoning them to the i^ath. In a moment the casucha would be sur- 

 rounded by them, and then down hill they would go again, helter-skelter and heels over head; 

 their drivers only stopping for a moment to light a cigar, or inquire about the condition of the 

 road below, and very soon we would be left to the dismal silence of the cordillera. 



There also passed a small train, consisting of some twenty mules, twelve of which were laden 

 with tobacco, intended to be smuggled into Chile. The owners of this were very particular in 

 their inquiries about the custom-house officers, and went on apparently satisfied with the in- 

 formation they had gained, for which they had but little reason, as the sequel proved. 



The night was so beautifully clear that I had the curiosity to set up the theodolite and turn 

 on Saturn. With its little telescope — only twelve inches long — I was able to make out the 

 rings clearly. 



Besides the road by which we ascended the spine of the mountains, there is another that 

 branches off about a mile below the casucha and curves the summit farther to the northward. 

 The descent on the eastern side by that is better than by this, but it opens later, and at the time 

 we passed was impracticable. 



November 23. — Finished work and started for the summit. Having arrived there, we were 



