718 LECTURE LVII. 



of Oppido, in the centre of this circle ; or under some part of the sea, be- 

 tween the west of Italy, and the volcanic island of Stromboli. This island^ 

 as well as Mount Etna, had smoked less than usual before the earthquake, 

 but they both exhibited appearances of an eruption during its continuance; 

 Etna towards the beginning, and Stromboli at the end. Before each shock 

 the clouds were usually motionless for a certain time, and it rained violently; 

 frequently also lightning and sudden gusts of wind accompanied the rain. 

 The principal shocks appeared to consist in a sudden elevation of the ground 

 to a considerable height, which was propagated somewhat like a wave, from 

 ■west to east: besides this, the ground had also a horizontal motion backwards 

 and forwards, and in some measure in a circular direction. This motion was 

 accompanied by a loud noise; it continued in one instance for ten seconds 

 without intermission: and it shook the trees so violently that their heads 

 nearly reached the ground. It affected the plains more strongly than the 

 hills. In some places luminous exhalations, which Sir William Hamilton 

 thinks rather electrical than igneous, were emitted by the earth : the^sea 

 boiled up near Messina, and was agitated as if by a copious discharge of 

 vapours from its bottom; and in several places water, mixed with sand, was 

 thrown up to a considerable height. The most general effect of these violent 

 commotions was the destruction of buildings of all kinds, except the light 

 barracks of wood or of reeds, into which the inhabitants retreated as soon as 

 they were aware of their danger: the beds of rivers were often left dry, while 

 the shock lasted, and the water on its return overflowed their banks : springs 

 were sometimes dried up, and new ones broke out in other places. The hills 

 "which formed the sides of steep vallies were often divided by deep chasms 

 parallel to the vallies; andin many cases large portions of them were separated, 

 and removed by the temporary deluge to places half a mile or a mile off; 

 with the buildings and trees still standing on them; and in this manner hills 

 were levelled, and vallies were filled up. But the most fatal accident of this 

 kind happened at Scilla, where so large a portion of a cliff" was thrown into 

 the sea, that it raised an immense wave, which carried off more than 2000 

 inhabitants who were collected on the beach, and even extended its formi- 

 dable effects to the opposite coast of Sicily, where several persons perished by 

 it in a similar manner. 



The eruptions of volcanos are usually attended by some shocks like those 

 of earthquakes, although commonly Jeas violent. Open volcanos continually 



4 



