LAmm, EllUl’lIOSS. 
lta 
in active volcanoes tie frequency of the eruptions is in the 
inverse ratio of the height and the mass. The Peak also 
had seemed extinguished during ninety-two years, when, in 
1798, it made its last eruption by a lateral opening formed 
in the mountain of Chahorra. In this interval Vesuvius 
had sixteen eruptions. 
The whole of the mountainous part of the kingdom of 
Quito may be considered as an immense volcano, occupying 
more than seven hundred square leagues of surface, and 
throwing out flames by different cones, known under the 
particular denominations of Cotopaxi, Tungurahua, and 
Pichincha. The group of the Canary Islands is situated 
on the same sort of submarine volcano. The fire makes 
its way sometimes by one and sometimes by another of 
these islands. Teneriflo alone contains in its centre an 
immense pyramid terminating in a crater, and throwing out, 
from one century to another, lava by its flanks. In the 
other islands, the different eruptions have taken place in 
various parts ; and we nowhere find those isolated moun- 
tains to which the volcanic effects are confined. The 
basaltic crust, formed by ancient volcanoes, seems every- 
where undermined; and the currents of lava, seen at Lan- 
cerota and Palma, remind us, by every geological affinity, 
of the eruption which took place in 1301 at the island of 
Ischia, amid the tufas of Epomeo. 
The exclusively lateral action of the peak of Teneriffe is a 
geological phenomenon, the more remarkable as it contri- 
butes to make the mountains which are backed by the prin- 
cipal volcano appear isolated. It is true, that in Etna and 
Vesuvius the great flowings of lava do not proceed from the 
crater itself, and that the abundance of melted matter is 
generally in the inverse ratio of the height of the opening 
" hence the lava is ejected. But at Vesuvius and Etna a 
lateral eruption constantly terminates by flashes of flame 
and by ashes issuing from the crater, that is, from the 
summit of the mountain. At the Peak this phenomenon 
has not been witnessed for ages : and yet recently, in the 
eruption of 1798, the crater remained quite inactive. Its 
bottom did not sink in ; while at Vesuvius, as M. von 
Bucli has observed, the greater or less depth of the 
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