260 Natural History of Volcanos and Earthquakes. 
tions subsist between all volcanos. The existence of such com- 
munications cannot be doubted. Immediately after the earth- 
uake which overthrew Caraccas, there followed the great 
eruption of the voleano of St. Vincent, and the earth no longer 
trembled at Venezuela. When the dense, black column of 
smoke, which, in the year of 1797, had issued for several 
months from the volcano near that city, disappeared, the cities 
of Riobamba, Hambato, and Tacunga, 280 English miles dis- 
tant, were at the same hour destroyed by a violent shock. 
Other instances of this kind will be mentioned afterwards. 
Andrea Lorenzo Curbeto’s description of the great volcanic 
eruption in the island of Lancerote, for which we are indebte 
to Von Buch,+ also shows how, for six years, from 1730 to 1736, 
the gaseous fluids in the interior found new vents in all direc- 
tions, sometimes here and sometimes there, and yet were not ca 
pable of preserving a single one permanently open. Sometimes 
two or three openings were formed at once, with a tremendous 
erash, accompanied with flames,(?) which alarmed the whole 
island. At one time, three apertures united suddenly into one 
very high cone; lava flowed out below and reached the sea. 44; 
says that acute geologist, the unhappy Lancerote had, like Tene 
rife, possessed a volcano, perbaps not one of those numerous 
cones would have been thrown up, and probably not a single 
village would have been destroyed.t He thinks it highly prob- 
able that this eruption took place entirely from one great rent. 
Lieder aiken oe 
* Von Humboldt Reise, t. 1. p. 498. Loco cit. 
$ Von Buch supposes that only the gaseous matters, but not solid substances, 
viz. lavas, slags, Japilli, and ashes, proceed from the focus of the yolcanie phe- 
nomena. He observes that these masses always show themselves to be of a na- 
ture corresponding to the rocks out of which they are ejected. 
must not furget that Von Buch was at that time still attached to Davy's hy- 
pothesis, which ascribes volcanic phenomena to the combustion of the metals of 
the alkalies and earths, and which does not require us to suppose the origin of 
volcanic action to lie at any great depth. Itis indeed, very different, according 
to the hypothesis which we are endeavoring to defend. In this, the seat of the 
volcanic actions is supposed to be identical with the place where the elastic forces 
producing them act. The connection between the lavas, and the slags, lapilli 
and ashes resulting from them, and the rocks at the surface, would only th 
4 e 
converting fusible rocks into a state of hydro-igneous fusion. 
