146 TRAVELS AMONGST THE GREAT ANDES, chap. vii. 



lower camp was distant about 8600 feet from the nearest part of 

 the crater, and in this distance we rose 4500 feet. Isolated snow- 

 patches commenced at about 15,400 feet, and a little higher we 

 were able to follow snoAV uninterruptedly right up to the slope 

 upon which I proposed to encamp. In order to ensure regularity 

 in the march, we tied up in line, a proceeding that our natives 

 did not at all comprehend, and they wondered still more at the 

 use of the axe in cutting steps in the snow, to facilitate progress. 

 The most interesting feature I noticed upon this section of the 

 mountain was the existence of glaciers upon the upper part of 

 the cone. They occurred on each side of us, and in some places 

 extended to within 500 feet of the top ; but, through being 

 much covered by ash, it was not possible to say exactly where 

 they commenced or terminated, and for the same reason they 

 were quite unrecognisable at a distance. 



At 11 a.m. we arrived at the foot of the great slope of ash 

 upon the western side of the summit, which leads right up to 

 the edge of the crater, and we found this was the steepest and 

 most laborious part of the ascent. I estimate it to be 750 feet 

 high, and 1100 feet long. It was composed of the materials 

 which are being daily, even hourly ejected ^ (mainly of particles 

 weighing about 500 to a grain, with an admixture of angular 

 fragments of lava up to a quarter of an inch in diameter), and 

 it was piled up nearly to the maximum angle at which it would 

 stand. I know experimentally that its materials will stand at 



^ The eruptions of Cotopaxi yield information respecting the prevailing winds 

 of this region, and shew clearly that they by no means blow uniformly from the 

 east, as some suppose. The slope of ash at the top of Cotopaxi, upon its western 

 side, proves, however, the preponderance of easterly winds at that particular spot 

 and elevation ; and from the whole of my experiences in Ecuador I should say 

 that in the interior generally, near the earth (at heights from 9000 to 10,000 feet) 

 easterly winds predominate, and that north-westerly ones are as rare as in Great 

 Britain. But wands blowing from the true east were almost equally scarce, 

 though north-easterly and south-easterly ones were frequent. From greater eleva- 

 tions (say 20,000-40,000 feet above the sea) there Avas abundant evidence of the 

 occurrence of powerful northerly and southerly winds, as well as easterly ones. 



