earthquakes arising from subterraneous vapours and eruptions: That the earth itself is not moved to any depths and that the shock must arise from the atmosphere. The circumstances which he has judiciously collected, are extremely agreeable to mine; many of them the very same, strongly confirming my hypothesis: And had that great man known the properties of electricity, which we are now masters of, he would have prevented me in this affair.
"Considering (says he) what variety of substances, sand, gravel, stones, rock, minerals, clay, and mold, our earth is compounded of, and how little nitre, or explosive matter, a large quantity thereof will afford; I cannot think, where we can find matter enough to move so vast a bulk of earth, as all the South parts of England, all the Netherlands, with part of Germany, all France, and perhaps Italy, (which were shock'd at once the 8th of September last 1692;) or part of Asia and near all Europe, which trembled together the same day, 91 years before.
"But, allowing there may have been sufficient matter prepared for these purposes, I can hardly think, there are continued cavities, at any reasonable depth, all under Europe, wherein an explosion being made, might shake the whole at once, and yet
make
