364 C aa f* tf Earthquakes . [Book VI. 



wards the city like a torrent, though againft both 

 wind and tide ; it rofe forty feet higher than was ever 

 known, and as fuddenly fubfided. A {hip, fifty leagues 

 off at fea, received fo violent a fhock as greatly to 

 injure the deck, &c. The fame effect was obferved 

 at Cadiz, and at a number of ports throughout the 

 Mediterranean, and, indeed, more or lefs, all over 

 Europe. 



That earthquakes are the effect of (learn generated 

 within the bowels of the earth, and that they are pro- 

 duced in the manner which has been defcribed, ap- 

 pears highly probable from the quantities of fteam and 

 boiling water which have occafionally been thrown up 

 by volcanoes in different parts of the world. In 1631 

 and 1698 van: torrents of boiling water flowed from 

 the crater of Vefuvius, previous to the eruption of 

 fire: and what was, perhaps, ftill more remarkable, 

 many fpecies of fea-fhells, in a -calcined ftate, were 

 found on the brink of the crater, and alfo in the chan- 

 Tiel formed by the flood. The fame thing happened 

 at yEtna, in 1755* when a dreadful torrent of boiling 

 water flowed from the crater at the time of an eruption 

 of fire. Sir William Harru'hon ob.feryes, that the fea- 

 jhells emitted along with the water clearly indicate a 

 communication with the fea. All warm fprings pro- 

 bably receive their heat from the action of pyrites, 

 near which the water paffes. 



The following account of the great Lifbon earth- 

 quake is extracted from a volume of letters, publifhed 

 a few years ago by the reverend Mr. Davy : 



* There never was a finer morning feen than the 

 firft of November (1755); the fun (hone out in its 

 full luftre; the whole face of the iky was perfectly 

 ferene and clear, and not the leaft fignal or warning of 

 that approaching event* which has made this once flou? 



rifhing. 



