236 VOLCANIC ROCKS. 
of the sea. Previously to the knowledge that has lately 
been attained respecting the Asiatic mountains, those 
of the Andes, on the continent of South America, had 
been considered by far the highest in the world. One 
of them, Chimborazo, is 20,900 feet in height. Of the 
European mountains, the highest is Mont Blanc, in 
Switzerland, which measures 15,680 feet, or about 2~ 
miles. The loftiest summit within the British islands is 
Ben Nevis, in Inverness-shire, Scotland, which does not 
exceed 4,380 feet, or somewhat more than three quar- 
ters of a mile ; and the great pyramid of Egypt, the 
loftiest work of human art and industry with which we 
are acquainted, and which will serve as a point in the 
scale, measures only 477 feet. 
272. It has been remarked that the greatest altitude 
at which bananas and other palm-trees grow in America 
is about 3280 feet above the level of the sea (Fig. 48) : 
that in the torrid zone, the superior limits of oaks is 
about 10,500 feet (49), of pines 12,000 feet (50), and 
of lichen plants 18,225 feet (51). The American travel- 
lers, Messrs. Humboldt and Bonpland, on the twenty- 
third of June, 1802, ascended the mountain of Chimbo- 
razo to the height of 19,400 feet (52). The highest 
flight that has been remarked of the South American 
vulture, called the condor, was 21,000 feet (53). M. 
Lussac, on the 16th of September, 1804, ascended in a 
balloon from Paris, to the height of 22,900 feet. In 
Switzerland, the limit of perpetual snow is above the 
altitude of 9000 feet (54). 
