ON AQUEOUS AND IGNEOUS METEORS. 561 



ignited materials, may in some measure be understood, from the acci- 

 dents which occasionally happen in founderies ; thus a whole furnace of 

 melted iron was lately dissipated into the air in Colebrook Dale, by the 

 effect of a flood, which suddenly overflowed it. 



The phenomena of earthquakes and volcanos are amply illustrated by 

 the particular accounts, transmitted to the Royal Society by Sir William 

 Hamilton, of those which have happened at different times in Italy.* The 

 earthquake, which desolated Calabria, in 1783, was fatal to about 40,000 

 persons, continuing its ravages for more than three months ; it destroyed 

 the towns and villages occupying a circle of nearly 50 miles in diameter, 

 lying between 38 and 39 degrees latitude, and extending almost from the 

 western to the eastern coast of the southernmost point of Italy, besides 

 doing considerable damage to places at much greater distances from its 

 origin, which is supposed to have been either immediately under the town 

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

 between 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 propa- 

 gated somewhat like a wave, from west to east : besides this, the ground 

 had also a horizontal motion backwards and forwards, and in some mea- 

 sure 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 ; and in many cases large portions of them were sepa- 

 rated, 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 



* Ph.Tr. 1767, Ivii. 192 ; 1768, Iviii. 1 ; lix. 18 ; 1780, Ixx. 42 ; 1783, p. 169: 

 and Count Ippolito, ibid. p. 209, 1795, 73. See also Hamilton's Observations on 

 the Volcanos of the Two Sicilies, 2 vols. fol. 1776. 



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