259 



rota*. It is probable, that, previous to the 

 sixteenth century, the other islands experienced 

 also the effects of the volcanic fire. Some vague 

 accounts were given me of an extinguished vol- 

 cano in the centre of the isle of Ferro, and of 

 another in the Great Canary, near Arguineguin. 

 But it would be curious to know whether traces 

 of subterranean fire are found in the calcareous 

 formations of Fortaventura, or in the granites 

 and mica-slates of Gomera. 



The merely lateral action of the Peak of Te- 

 nerifFe is a geological phenomenon, so much the 

 more remarkable, as it contributes to make 

 mountains, which are backed by the principal 

 volcano, appear isolated. It is true, that in 

 Etna and Vesuvius, the great flowings of the 

 lavas do not proceed from the crater itself, and 

 that the abundance of melted matter is generally 

 in the inverse ratio of the height, at which the 

 opening that ejects the lava, takes place. But 

 at Vesuvius and Etna a lateral eruption con- 

 stantly finishes by flashes of flame and by ashes ? 

 which issue from the crater, that is, from the 

 summit of the mountain. At the Peak, this 

 phenomenon has not taken place for ages : and 

 yet recently, in the eruption of 1798, the crater 

 remained quite inactive. It's bottom did not 

 sink in, while at Vesuvius, as Mr. von Buch 



* Vieyra, Noticias. t. ii. p. 404; t iii, p. 151, 288, 352^ 

 356, and 516. 



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