1st. As far as we can possibly learn, where no one can be prepar'd, at different places, by time keepers; this mighty concussion was felt precisely at the same instant of time; being about half an hour after twelve at noon. This, I presume, cannot be accounted for, by any natural power, but by that of an electrical vibration; which, we know, acts instantaneously. 2dly, Let us reflect on the vast extent of this trembling, 100 miles in length, 40 in breadth, which amounts to 4000 square miles in surface. That this should be put into such an agitation, in one moment of time, is such a prodigy; as we should never believe, or conceive, did we not know it to be fact, from our own senses. But if we look for a solution of it, we cannot think, any natural power is equal to it, but that of electricity; which acknowledges no sensible transition of time; no bounds. 3ly, We observe, the vulgar solution of subterraneous eruptions receives no countenance, from all that was seen, or felt, during these earthquakes. It would be very hard to imagine, how any such thing could so suddenly, and instantaneously operate, thro' this vast space: and _that_ in so similar, and tender a manner over the whole, thro' so great a variety, as well as extent of country; as to do no mischief. A philosophical inquirer in _Northamptonshire_ had his eye particularly on this point, takes notice, there were not any fissures in the ground; any sulphureous smells, or eruptions any where perceiv'd; so as to favour internal convulsions of the earth. The reverend Mr. _Nixon_ of _Higham_, and Mr. _Smith_, in his letter from _Peterborough_ take notice, that they could not learn, there were any sort of eruptions out of the earth, any where: no smoke, vapor, or smell: tho' they made sufficient inquiry about that circumstance, according to particular direction. Yet we learn from a letter at _Uppingham_ in _Rutland_, that a plaister floor became crack'd thereby. These kind of floors are frequent in this country; what we call _stucco_ in _London_: and it gives us a good notion of the undulatory vibration, produc'd by an earthquake; which some have compar'd to that of a musical string: others to that of a dog, or a horse shaking themselves, when they come out of the water. This last comparison would have pleased some of the ancients, who would needs fancy, that the globe of the earth was a great animal. _Plato_, _Plutarch_, and others, had such kind of sentiments. Whence one may imagine, that they would conceive an earthquake to be, as when a horse shakes a part of his skin, upon a fly touching him. Some of our correspondents express the motion of an earthquake to be like a boat lifted up by one wave, let down by another.