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We should notice that, previous to an eruption of Vesuvius, the earth always trembles, and sub¬ 
terraneous explosions are heard. On the first of November, 1755 , the sera so fatal to Lisbon, the island 
of Madeira was violently shaken by an earthquake, accompanied with subterraneous explosions. So 
thoioughly convinced, indeed, aie the inhabitants of volcanic countries of the connection between 
eaithquakes and "volcanoes, that when a great eruption takes place from a volcano, they congratulate 
themselves on having escaped an earthquake. 
Earthquakes, as well as volcanic eruptions, are always preceded by a violent agitation of the sea. 
Previous to the breaking out of Vesuvius, the sea retires from the adjacent shores till the mountain is 
burst open, and then it returns with such impetuosity, as to overflow its usual boundary. About an 
hour after the first shocks, which alarmed the city of Lisbon in 1765, the sea was observed to come 
rushing towards the city like a torrent, though against both wind and tide; it rose forty feet higher 
than was ever known, and as suddenly subsided. A ship, fifty leagues off at sea, received so violent 
a shock as greatly to injure the deck, &c. The same effect was observed at Cadiz, and at a variety of 
ports throughout the Mediterranean, and, indeed, more or less, all over Europe. 
In 1691 and 1698 vast torrents of boiling water flowed from the crater of Vesuvius, previous to the 
eruption of fire: and what was, perhaps, still more remarkable, many species of sea-shells, in a cal¬ 
cined state, were found on the brink of the crater, and also in the channel formed by the flood. The 
same thing happened at iEtna, in 1/55, when a dreadful torrent of boiling water flowed from the 
crater at the time of an eruption of fire. Sir William Hamilton observes, that the sea-shells emitted 
along with the water clearly indicate a communication with the sea. All warm springs probably 
receive their heat from the action of pyrites, near which the water passes. 
The following exact account of the great Lisbon earthquake is extracted from a volume of letters, 
published by the Rev. Mr. Davy. 
There was never a finer morning seen than the first of November ( 1755 ); the sun shone out in its 
full lustre; the whole face of the sky was perfectly serene and clear, and not the least signal or warn¬ 
ing of that approaching event, which has made this once flourishing, opulent, and populous city, a 
scene of the utmost horror and desolation, except only such as served to alarm, but scarcely left a mo¬ 
ment’s time to fly from the general destruction. 
It was on the morning of this fatal day, between the hours of nine and ten, that I was sat down 
in my apartment, just finishing a letter, when the papers and table I was writing on began to tremble 
with a gentle motion, which rather surprised me, as I could not perceive a breath of wind stirring; 
whilst I was reflecting with myself what this could be owing to, but without having the least appre¬ 
hension of the real cause, the whole house began to shake from the very foundation, which at first I 
imputed to the rattling of several coaches in the main street, which usually passed that way, at this 
time, from Belem to the palace: but on hearkening more attentively, I was soon undeceived, as I 
found it was owing to a strange frightful kind of noise underground, resembling the hollow distant 
rumbling of thunder; all this passed in less than a minute, and I must confess I now began to be 
alarmed, as it naturally occurred to me, that this noise might possibly be the forerunner of an earth¬ 
quake, as I remembered that which had happened about six or seven years ago, in the island of Madeira, 
commenced in the same manner, though it did little or no damage. 
Upon this I threw down my pen, and started upon my feet, remaining a moment in suspense, 
whether I should stay in the apartment, or run into the street, as the danger in both places seemed 
equal; and still flattering myself that this tremor might produce no other effects than such inconsider¬ 
able ones as had been felt at Madeira; but in a moment I was roused from my dream, being instantly 
stunned with a most horrid crash, as if every edifice in the city had tumbled down at once. The house 
I was in shook with such violence, that the upper stories immediately fell, and though my apartment 
(which was the first floor) did not then share the same fate, yet every thing was thrown out of its 
place in such a manner, that it was with no small difficulty I kept my feet, and expected nothing less 
than to be soon crushed to death, as the walls continued rocking to' and fro in the frightfullest man¬ 
ner, opening in several places, large stones falling down on every side from the cracks, and the ends 
of most of the rafters starting out from the roof. To add to this terrifying scene, the sky in a moment 
became so gloomy, that I could now distinguish no particular object; it was an Egyptian darkness 
indeed, such as might be felt; owing, no doubt, to the prodigious clouds of dust and lime, raised from 
so violent a concussion, and as some reported, to sulphureous exhalations, but this I cannot affirm ; 
however, it is certain I found myself almost choked for near ten minutes. 
