IM M. Humboldt on Volcanoes, £Auo. 



When the summits of volcanoes (as is generally the case in 

 the chain of the Andes), extend into the region of eternal snow, 

 or even to double the height of iEtna, the melted snow rendera 

 the inundations amazingly frequent and destructive. They are 

 phtcnomena meteorologically connected with volcanic eruptions, 

 and are multifariously modified by the altitude of the mountains, 

 the extent of their summits covered with eternal snow, and the 

 calefaction of the sides of the cone of ashes ; but they should 

 never be considered as real volcanic phjenomena. Subterranean 

 lakes, in connexion with alpine rivers, are formed both on the 

 slopes and at the feet of the mountains. When the earthquakes 

 which precede every eruption in the chain of the Andes, shake 

 with mighty force the entire mass of the volcano, the subterra- 

 nean vaults are opened, and emit, at the same time, water, tishesj 

 and tufa-mud. This is the singular phenomenon that fur- 

 nishes the fish pimelodes cyclopum, which the inhabitants of 

 the high lands of Quito call prenadilloj and which was described 

 by me soon after my return. When the summit of the mountain 

 Carguairazo, to the north of Chimborazo, and 18,000 feet 

 high, fell, in the night between the 19th and 20th of June, 

 1698, the surrounding fields, to the extent of about 43 Eng- 

 lish square miles, were covered with mud and fishes. The 

 fever which raged in the town of Ibarra, seven years before, had 

 been ascribed to a similar eruption of fishes from the volcano 

 Imbaburu. I recur to these facts, because they throw some 

 light on the difference between the eruption of ashes, and that 

 of mud-like masses of tufa and trass, which contain wood, 

 coal, and shells. 



The quantity of ashes ejected by Vesuvius in the late erup- 

 tions, like all other things which are connected with great and 

 appalling phajnomena, has been enormously exaggerated in the 

 puulic papers ; and two Neapolitan chemists, Vincenzo Pepe, 

 and Giuseppe di Nobili, have affirmed, that they contain gold 

 and silver, notwithstanding the contradiction of Monticelli and 

 CoveUi.* According to my examination, the stratum of ashes 

 which had fallen in twelve days, towards Bosche tre Case, on 

 the slope of the cone, where rapilli were mixed with it, was 

 only three feet in thickness, and in the plain, it did not 

 exceed from 15 to 18 inches. Measurements of this kind 

 must not be made in places where the ashes have been drifted 

 by wind, like snow, or sand, nor in those where they have been 

 accumulated by water. The times are past in which we sought 

 only for the marvellous in volcanic pha3nomena, and, like Ctesias, 

 made the ashes of JEtno. fly to the Indian peninsula. Some of 

 the Mexican gold and silver mines are certainly in trachytic 

 porphyry, but in the ashes of Vesuvius which I collected, and 

 which, at my desire, have been analyzed by Henry Rose, of 



• See AnnaUy v. 236. 



