376 ON VOLCANOES AND EARfHGLUAKES. 



earthquake of Sicily, in 1693, destroyed fifty-four 

 towns ; but those of Italy are innumerable. 



The earthquake of Lisbon, in 1755, was one of the 

 most extensive in its effects of any that has been 

 described, and is, on that account, particularly in- 

 teresting. It was felt all over Portugal and Spain, in 

 Madeira, and in some parts of Africa, and, in a slighter 

 degree, in Sweden, Italy* France, and England. The 

 waters of wells and lakes showed the disturbance of 

 the earth, in many places where the tremor was not 

 remarked ; becoming agitated, turning muddy, over- 

 flowing their banks, or fluctuating and rising in pyra- 

 midal waves. Even the sea was thus affected; not 

 only on the shores of these countries, but far off in 

 the ocean. The places where these effects were 

 perceived, were Norway, Sweden, Germany. Corsica, 

 Switzerland, Antigua, Barbadoes, and Ireland ; mark- 

 ing the deep seat, as well as the wide range of the 

 disturbance. The last events of this nature which are 

 here worth recording are those continued earthquakes 

 which took place in Calabria between 1783 and 1786; 

 involving a circle of seventy-two miles in radius, and 

 producing the destruction of twenty thousand persons. 

 In these catastrophes, a hundred and eighty-two towns 

 and villages were demolished, and ninety-two injured; 

 and the circle of complete destruction, of which Oppido 

 was the centre, had a radius of twenty-two miles. 



Earthquakes are most frequent and complete in 

 volcanic countries, and are expected when volcanoes 

 have been long dormant ; a proof of the community 

 of their causes. They are generally preceded by 

 various unusual meteoric phenomena, by a peculiar 

 state of the atmosphere, attended with uncommon 

 sounds resembling thunder. Wells and springs are 

 rendered muddy, or dry up, or become more abundant; 



