228 Baron Humboldt on the Structure and Action of 



perpetual snow, and are probably situated upon a crevice tra- 

 versing the whole continent, over an extent of 105 geographical 

 leagues from the Pacific Ocean to the Atlantic. 



This association of volcanoes, whether in isolated and rounded 

 groups, or in longitudinal bands, demonstrates, in the most de- 

 cisive manner, that volcanic effects do not depend upon slight 

 causes existing near the surface of the earth, but are phenomena 

 whose origin is to be found at a great depth in the interior of 

 the globe. The whole eastern part of the American continent, 

 which is poor in metals, is, in its present state, destitute of vol- 

 canic mountains, of masses of trachyte, and probably even basalt, 

 with olivine. All the American volcanoes are collected together 

 in the chain of the Andes, which is situated in the part of that 

 continent opposite to Asia, and which extends, in the direction 

 of the meridians, over a space of 1800 leagues. The whole 

 plain of Quito, of which Pichincha, Cotopaxi, and Tunguraqua 

 form the cymes, is a volcanic focus. The subterranean fire 

 escapes, sometimes by one, sometimes by another, of those aper- 

 tures which it has been customary to consider as distinct vol- 

 canoes. The progressi^^e march of the fire in them has, for the 

 last three centuries, been from north to south. The very earth- 

 quakes, which produce such terrible ravages in this part of the 

 world, afford remarkable proofs of the existence of subterranean 

 communications, not only with countries destitute of volcanoes, 

 which has been long known, but also between ignivomous 

 mountains placed at very great distances from each other. 

 Thus, in 1797, the volcano of Pasto, to the east of the course of 

 the Guaytara, vomited, unremittingly, for three months, a high 

 column of smoke. This column disappeared at the very mo- 

 ment, when, at a distance of sixty leagues, the great earthquake 

 of Riobamba, and the muddy eruption of Moya, destroyed 

 about forty thousand Indians. The sudden appearance of the 

 Island of Sabrina, to the east of the Azores, on the 30th Janu- 

 ary 1811, was announced by the dreadful earthquake, which, 

 at a much greater distance to the west, from May 1811 to June 

 1812, shook, almost without intermission, first the West India 

 Islands, then the plains of the Ohio and Missisippi, and, lastly, 

 the coasts of Venezuela, situated on the opposite side. Thirty 

 days after the total destruction of the city of Caraccas, the ex- 



