148 EARTHftUAKF.S. , f 
of dew, rain, springs, and rivers, being diverted 
ordinary course by some accidental obstruction in * 
through which it used to ascend to tire surface, 
by such means, preternaturally assembled, in ® °(/ 
quantity than usual, in one place, and thus cause* ^ 
fiction and intumescence of the water of the abyss- 
In-r it into greater commotions, and at the same xd' 
ing the like effort on the earth, which, being exp^ ) 
the surface of the abyss, occasions an earth«iuaK^,j ’ 
Mitchell supposes tliese phenomena to be occasio a 
subterraneous fires, which, if a large quantity ^ 
let loose on them suddenly, may produce a 
quantity and clastic force of which may fully ^ 
tire purpose. Again, M. Amoutons, a menibtt j||.» 
French Academy of Sciences, endeavours to prov 
on the principle of the experiments made on lb® Dll'' 
and spring of the air, a moderate degree of heat 
that element into a state capable of causing earths'- 
Modern electrical discoveries have thrown 
on this subject. Dr. Stukely strenuously denies 
quakes are to be ascribed to subterraneous wind*.^ '' 
vapours ; and thinks that there is not any evident® jK 
cavernous structure of the earth, which such an b.' rg/, 
requires. Subterraneous vapours, he thinks, i"'® i''d 
inadequate to the effects produced by earthquak®-.j^,|ii‘ 
particularly in cases where the shock is of 
extent : for a subterraneous power, capable ot 
surface of earth only thirty miles in diameter, yJ- 
lodged at least fifteen or twenty miles below th® 
ancf move an inverted cone of solid earth, 
thirty miles in diameter, and axis fifteen or l"'®‘ ,|, 
w'hich he thinks absolutely impossible. How nii ^ It 
inconceivable is it, then, that any such powei j 
produced the earthquake of 1755, which wa.-. 
ous parts of Europe and Africa, and in the x\tku' 
or that which in Asia Minor, in the seventeenth j,, 
the Christian era, destroyed thirteen great , 
night, and shook a mass of earth three hundred 
diameter. To effect diis, tlie moving power, sul \o^. 
to have been internal fire or vapour, nmst have o , . 
two hundred miles beneath the surface of the e*' 
sides, in earthtjuakes, the effect is instantaneous > 
