Volcanoes, 



633 



acquainted is comparatively small. We have not authenticated 

 accounts of more than two hundred. But, in forming our 

 estimate of the extent of volcanic action, we must keep in 

 mind that in the interior of the Americas, and other uninves- 

 tigated districts, very many volcanic mountains may hereafter 

 be discovered ; and that it is by no means improbable that 

 those which we now consider extinct, are in the phase of 

 prolonged intermittence, and may again break forth with 

 overpowering energy : and we are entirely ignorant of the 

 number of subaqueous volcanoes ; for not only may there be 

 many in the phase of prolonged intermittence, but those in 

 frequent activity are inadequately known. 



In tracing the geographical position of the active volcanoes 

 with which we are acquainted, we shall commence with Vesu- 

 vius, in the kingdom of Naples. The first recorded eruption 

 of this mountain was in the year 79, when the celebrated 

 cities of Herculaneum and Pompeii were destroyed. Dr. Dau- 

 beny is of opinion that the cone of Vesuvius did not exist till 

 this time, and that the eruption which buried those devoted 

 cities formed the cone of the present mountain. This 

 probability is strengthened by the fact, that the measure- 

 ment we have of the distance of the mountain from Pompeii 

 and Stabiae can only be reconciled with its present situation 

 by measuring from the foot of Monte Somma. Hence, then, 

 we may be permitted to suppose, that by the eruption of 

 79 Somma was destroyed, and Vesuvius is but the cone which 

 was formed within that mountain, increased by successive 

 eruptions ; and that, previously to this time, all eruptions were 

 from the crater of Somma. {Jig, 111.) An account of the phe- 



nomena which attended this remarkable activity may be seen 

 in Pliny's Epistles^ lib. vi. ep. 20. After this it seems to have 

 fallen into the phase of prolonged intermittence, but was again 

 in action in the year 203. It was also violently agitated in 

 472, and covered all Europe with its ashes ; but it was not 



