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circumftances accompanying them are not related. 
Indeed it is hardly to be expedted that they fhould 
be observed, much lefs that they fhould be related, 
when they happened in a country fo thinly inhabited, 
and where one may reafonably fuppofe, that, in ge- 
neral, only the grofler and more violent effedts would 
be taken notice of. 
Sect. TIL 
5T- I have faid before, that I imagined earth- 
quakes were caufed by vapours raifed from waters 
luddenly let out upon fubterraneous fires. It is not 
eafy to find any other caufe capable of producing 
fuch hidden and violent effedts, or of railing fuch ail 
amazing quantity of vapour in fo fmall a time. That 
the blahs, difcharged from volcanos, are always pro- 
duced from this caufe, is highly probable ; that they 
are often fo,* cannot admit of the leah doubt. There 
can be no doubt, that confiderable quantities of water 
muh be often let out upon the fires of thefe volcanos, 
and whenever this happens, it will be immediately 
raifed by the heat of them into a vapour, whofe 
elahic force is capable of producing the moh violent 
effedts *. 
y6. Both 
* There are many effedts produced by the vapour of water, 
when intenfely heated, which make it probable, that the force of 
gunpowder is not near equal to it. The effedts of an exceeding 
fmall quantity of water, upon which melted metals are acci- 
dentally poured, are fuch, as, I think, could in no wife be ex- 
pected from the like quantity of gunpowder. Founders, if they 
are not careful, often experience thefe effedts to their coft. An 
accident of this kind happened about forty years fince, at the cart- 
ing of two brafs cannon at Windmill-hill, Moorfields. The 
“ heat 
