270 Natural History of Volcanos and Farthquakes. 
throwing up so many red hot stones and fragments of rock, as to 
form a mountain within twenty-four hours.* 
The last occurrence we shall mention, and which is still fresh 
in our memory, namely, the volcanic island which appeared in 
July, 1830, in the Mediterranean, between the southwest coast 
of Sicily and Pantellaria, shews, that these phenomena may take 
place in two different ways. New islands may be formed in the 
sea either by the elevation of solid rock, by violently breaking 
and raising up the original strata, or merely by the heaping up of 
the loose masses which are ejected. This event was of the lat- 
ter description, and in its ephemeral existence exactly resembles 
above-mentioned case in the Azores. Under which of these 
forms such volcanic productions appear, may depend on the na- 
ture and thickness of the rocks to be broken through, on the depth 
of the sea at the place of the eruption, and the strength of the 
voleanic force. However, the visible part of this island may, 
perhaps, as is the case with many others, only have been the 
summit of a peak situated in the centre of a crater of elevation, 
which remained buried in the sea, similar to the cones of many 
land volcanos, which, if they had been situated in the sea, would 
have been unable long to. withstand the action of the waves, asis 
the case with most of these islands. Hoffmann,{ who approached 
very near to this island, shortly after its appearance, saw quite 
plainly, that it was nothing else than the edge of a crater, the 
walls of which were gradually raised above the surface of the wa 
ter by the materials ejected from it. From this crater vapors 
rose uninterruptedly with great violence, yet without noise, which 
were succeeded by the ejection of slags, sand, and ashes. The 
appearance of this island was also preceded by a noise resembling 
thunder, and by the elevation of a mass of black colored water to 
a height of eighty-two feet, columns of smoke rising at the same 
time to a great height.. The accounts leave us in uncertainty 
respecting one of the most important circumstances—whether 
fire rose out of the crater or not. However, Hoffmann and his 
companions are inclined. to’ the more probable opinion, that this 
voleano vomited no fire, and that what some observers took for 
aoe 
* Annal. de Chim, et de Phys. t. xxvii, p. 382. ; 
{ See, on the contrary, Von Humboldt in his Reise, t. i, p. 254, note. 
+ Poggendorff’s Ann. t. xxiv, p. 75. 
