1531, At Lisbon, 1400 houses thrown down; as many shatter'd.
April, 1690, The Leeward-Islands, Montserat, Nevis, and Antigua: At Martinico, and the French islands, at St. Lucia, &c. a violent earthquake.
Dec. 8, 1703, An earthquake at Hull, a perfect calm.
1702, At Stroution, in Argyleshire, which extended all along the west coast of Great-Britain; but to no breadth on land.
Oct. 25, 1734, At Havant, in Sussex, considerable, the air perfectly calm.
But instances enough, to show what I aim'd at, that maritime places are most subject; which is a strong argument in favour of electricity; when both the solid of the earth, and the quantity of the water concur, to make the shock; exactly as in electrical experiments; when the bottle of water is held in the hand.
Thus when our mind is discharged of the prejudices of former notions, we discern, that every appearance favours the principle we go upon. That, agreeable to Mr. Flamsted, subterraneous explosions, could they pervade, and traverse the earth at pleasure, must at last burst, and disperse every thing in their way. Yet 'tis not possible for us to imagine, such a kind of vibration should follow, either by sea or land, as that we are treating of. But electricity compleatly answers it. This accounts for that superficial movement of the earth, that universal instantaneous shock, which made every house in London to tremble, none to fall: That quivering, tremulous, horizontal vibration, highly different from any motion we must conceive, to be produc'd from subterraneous evaporations. Hence authors tell us, Dec. 30, 1739, describing an earthquake in the west-riding of Yorkshire: It seem'd as if the earth mov'd backward and forward horizontally; a quivering, with reciprocal vibrations.
Mr. Flamsted rightly accounts the motion of earthquakes to be undulatory; and by being continued, causes a like motion to a great distance. As when you strike a long stretch'd string of wire at one end, the motion is immediately continued to the other. So far he entered into the nature of electricity.
Tho' he be in the right, thinking the cause comes from the air, yet what follows, contradicts his own hypothesis. For if a calm be necessary before an earthquake; then 'tis not produc'd by any turbulence in the air. Nor can we imagine that any aerial commotion, tho' it may shake windows, chimneys, and the like, shall reach 500 miles distance, split the solid earth, destroy whole cities, and cause those dire desolations we hear of.