S06 M. Humboldt on txeo Attempts to ascend Chimborazo. 



That part of our expedition which lay above the snow-line, had 

 lasted only 3^ hours, during which, notwithstanding the tenuity 

 of the air, we hadnotfound it needful to take rest by sitting down. 

 The diameter of the dome-shaped summit at the snow-line — i. e. 

 at the height of 2460 toises — amounts to 3437 toises, and near 

 the apex, about 150 toises below the same, the diameter is 

 67^ toises. The last number is thus the diameter of the up- 

 per part of the dome or bell ; the first expresses the breadth, 

 of which the whole snow-mass of Chimborazo appears to the 

 eye, as seen from Rio Nuevo ; a mass which, together with the 

 two mountain-tops lying to the north, is i-epresented in the 16th 

 and 25th table of my engraved work, Vties des CordilUres. 1 

 have carefully measured with the sextant, the single parts of the 

 contour, as the latter, on a clear day, magnificently stands forth 

 in opposition to the deep-blue of a tropical sky. Such observa- 

 tions assist in thoroughly exploring the volume of this colossus, 

 in so far as it surmounts a plain, in which Bonguer performed 

 his experiments on the attraction of the mountain for a pendu- 

 lum. A distinguished geognost, M. Pentland, to whom we are 

 indebted for a knowledge of the heights of Sorata and Illimani, 

 and who, furnished with excellent instruments for astronomical 

 and physical research, is now again going to upper Peru (Boli- 

 via) has assured me, that my figure of Chimborazo is, as it 

 ■were, repeated in the Nevado de Chuquibamba, a trachyte moun- 

 tain of the Western Cordilleras, north of Arequipa, having a 

 heio-ht of 19,680 feet (3280 toises). Next to the Himmalayan 

 mountains, this is, owing to the frequency of high summits 

 and the mass of the same, between the 15th and 18th degree of 

 south latitude the greatest enlargement on the earth's surface, with 

 which we are acquainted, in so far namely, as this enlargement 

 proceeds, not from the primitive form of the revolving planet, 

 but from the elevation of mountain-chains and suigle domes of 

 dolerite, trachyte, and albite rock, within these mountain-chains. 



On account of the snow newly fallen, we found in our de- 

 cent from Chimborazo, the lower limit of perpetual snow, in 

 accidental and temporary conjunction with the deeper sporadial 

 spots of snow on the naked lichen-covered rocks, and on the 

 <rrass plain (Pajonal) ; yet it was always easy to recognise the 

 proper limit of perpetual snow (then at the height of 2470 toises) 

 by the thickness of the bed and by its peculiar state. I have 



