[ 566 ] 
LV. Conjectures concerning the Caufe , and 
Obfer vat ions upon the Phenomena of 
Earthquakes ; particularly of that great 
Earthquake of the Fir ft of November, 
1755, which proved fo fatal to the City of 
Lifbon, a?id whofe EfteCls were felt as far 
as Africa, and more or lefs throughout 
almcft all Europe; by the Reverend John 
Michel 1 , M. A. Fellow op Queen's College y 
Cambridge. 
INTRODUCTION. 
Art. i.TT has been the general opi- 
| nion of philolophers, that 
earthquakes owe their origin to fome 
fudden explolion in the internal parts of the earth. 
This opinion is very agreeable to the phenomena* 
which feem plainly to point out fometliing of that 
kind. The conjectures, however, concerning the 
caufe of fuch an explofion, have not been yet, I think, 
fufficiently fupported by fadts; nor have the more 
particular effedts, which will arife from it, been 
traced out; and the connexion of them with the 
phenomena explained. To do this, is the intent of 
the following pages; and this we are now the better 
enabled to do, as the late dreadful earthquake of the 
id: of November 1755 fupplies us with more * fads, 
and 
* Many of thefe fa£ts are collected together in the 49th »'oIume 
of the Philofophical Tranfadtions. The fame are alfo to be found. 
With 
Read Feb. 28. 
March 6. 1 3. > 
20. 27. 1760 ) 
