379 
felt in England, November 18, 1 795. 
spherical appearances, with which the earthquake here de- 
scribed and many others have been accompanied, and sup- 
pose all those appearances merely accidental, and unconnected 
with the earthquakes. It is not, however, my intention to 
enter into a minute examination of this part of the subject ; but 
I cannot refrain from hinting, that those who may hereafter 
be inclined to do so would perhaps do right to begin by in- 
quiring, whether all commotions of the earth which go under 
the name of earthquakes are really produced by the same 
cause.* After that, as a subject so full of difficulties ought to 
be viewed in every possible light, it might not be amiss to con- 
sider whether, supposing the cause of an earthquake situated 
in the earth, that cause may not be capable of affecting the 
atmosphere, in such a manner as to occasion those appearances 
in it which we find so difficult to explain ; or whether, if the 
cause be supposed to be seated in the atmosphere, certain 
tracts of country may not (from some circumstances with 
which we are unacquainted) possess a peculiar disposition to 
bring that cause into action, by co-operating with it. 
* To prove that this is pot an unnecessary inquiry, it might perhaps be sufficient to 
refer to what has been said respecting the agitation of the waters; (page 376;) but, as 
a farther proof that earthquakes either differ from each other, or appear to do so to 
different persons, I may add, that though I have endeavoured to show that the slow- 
ness with which earthquakes sometimes move is a strong argument against their being 
caused by electricity, yet Dr. Stukeley, the first promulgator of the electric theory, 
as one of his arguments in its favour, says that, as far as he could learn, the earthquake 
of September 30, 1750, was felt over its whole extent precisely at the same instant. 
(See Phil. Trans. Vol. XLVI. page 738.) Beccari a also, whose theory is an electric 
one, (though very different from Dr. Stukeley’s, inasmuch as he considers the elec- 
tric fluid within the earth to be the chief agent,) lays great stress, in support of his 
theory, upon the velocity with which, as he says, earthquakes move. See Becccvria, 
dell ’ Elettricismo artificiale e naturale. Cap. vii. § 679. 
