CHAP. II. TEE BAROMETERS. 33 



undergone vicissitudes. Sometimes it has been greater and 

 sometimes smaller.^ Humboldt says {^^ Aspects of Nature, vol. 1, 

 p. 96) that until 1820 it was still regarded as '^the highest 

 summit on the surface of the earth." ^ It looked very large 

 from Guaranda. The snowy part that was visible (and this was 

 only a fraction of the whole) extended nearly over a point of 

 the compass (ten degrees and a half). We were more than 

 twice the distance from it that the Brevent is from Mont Blanc^ 

 yet at that distance its crevasses and schrunds appeared larger 

 and more formidable than the crevasses on Mont Blanc which 

 can be seen from the Brevent. It was clear that an ascent was 

 not to be effected without labour. The route that I j)i'oposed 

 to take seemed the easiest if not the only way by which it 

 could be ascended on the side of the Arenal. 



While the Carrels were away prospecting, I gave attention to 

 the barometers, for measurement of atmospheric pressure was the 

 first consideration, as this was at the bottom of all the work which 

 was to be undertaken. I took to Ecuador two mountain mercurial 

 barometers of the Fortin pattern/ as well as boiling-point ther- 

 mometers and aneroids. Although the employment of aneroids, 

 and the boiling-water method are recommended in works of 

 authority* for the determination of differences of pressure, I 



^ Juan and Ulloa made it 21,615 feet ; La Condamine, 20,592 feet ; Humboldt, 

 21,425 feet; and Reiss and Stiibel, 20,703 feet. 



^ This teaching seems to have prevailed at a later date, for in the first and 

 second editions of E. Barrett Browning's Aurora Leigh, published in 185(>-7, the 

 following passage occurs : — 



"I learnt the royal genealogies 

 Of Oviedo, the internal laws 



Of the Burmese empire, ... by how many feet 

 Mount Chimborazo outsoars Himmeleh." 



3 And left a third one (Kew pattern) with Mr. Chambers for simultaneous 

 comparisons at Guayaquil. 



* See Hints to Travellers, sixth edition, pp. 89, 305, 309, etc. 



F 



