The Philosophy of Earthquakes, Natural and Religious / or, An Inquiry Into Their Cause, and Their Purpose

by William Stukeley

Mr. Flamsted mentions a circumstance, that the earthquake here in 1692, was not felt in the north of England, nor in all Scotland: for rain fell that day in both. We may very readily conceive, the earth there was not in an electrified state; and the rain would sufficiently prevent it. We hence understand, how the southern regions should be more subject to them, than our northern; where the warmth, and driness of the air, so necessary to electricity, is more frequent than with us.

From electric vibration only can we account for our tenth position, of springs, and fountains being no ways damag'd by earthquakes: The motion goes no deeper into the earth, than the force and quantity of the shock reaches; which generally is not far; yet it proceeds lower down when the ready passage of a well offers, and there affects the water contained in it; puts it into an intestine vibration, as to foul it, and raise mud from the bottom.

It may seem difficult to conceive, how a large portion of the earth's surface should be thus capable of electrification. This difficulty is lessened by reflecting on the nature of electricity, and of the electrical, ethereal fluid pervading all things: how it is excited by the little motion of a small revolving glass globe. By this we electrify the most solid bodies, to the greatest distance, and with a velocity equal to that of lightning.

Dr. Hales observes, that the usual explosion of the cannon on great days, in St. James's-Park, is observ'd to electrify the glass, in the windows of the Treasury.

We must conceive, that when the electric shock is communicated to one part of the earth, it extends itself proportionably to the force of the shock, and to the quantity of electrified surface; and to the quality of the matter more or less susceptible of it, more or less apt to propagate it.

Set 1000 men in a row; let every one communicate with those next him by an iron-wire held in their hands: on an electrical shock they all feel it alike, at the same instant; and this gives us a very good idea of the earthquake.

When the earth is broken up in any large degree, 'tis by the sea-side; where sometimes on a bold shore, whole streets tumble into the sea, or into the gaping earth, now falling toward the sea. Sometimes on a flat and sandy shore, whole streets are rolled along the level into the sea.

I am not sensible of any real objection against our hypothesis, but this, being the eleventh of my positions, or circumstances. It seems true, that earthquakes are more frequent in Italy, near Vesuvius, and by Ætna, in Sicily. And the cause seems apparently owing to these vulcano's. At first sight, every one would think so, but not from the true reason. This has given the great prejudice to the judgments of the curious, even at this day. But consider the matter impartially, and it will appear, so far from being a strong argument in favour of subterraneous eruptions, that it ought to be esteem'd a convincing proof to the contrary, and most cogent in favour of my principle. In strictest logic, there is no inference to be made from particulars to generals. Quite the contrary. We have but these two or three vulcano's on one quarter of the globe, and two of them toward the warmer climate of it; whereas earthquakes are innumerable, especially in those of a warmer clime. That there are no vulcano's, no discharges of fire and smoke for a continuance, and abundance, after earthquakes; no suspicion of it either from sight or smell, as we know by innumerable examples, as well as in our own country, and experience: is demonstration, that this is not the cause. If the vulcano's were the real cause of earthquakes, we ought assuredly to expect, that in the countries thereabouts, the earthquakes ought to be far more extensive than those in other countries, where are no vulcano's; but this is altogether contrary to experience. For, as the celebrated naturalist Buffon observes, such are not extensive, as are near Ætna and Vesuvius. He further adds: Histoire naturelle, tom. I. p. 508. speaking, among many others, of a vulcano in the island of Ternate, he remarks, "That this burning gulph is less agitated when the air is calm, and the season mild, than in storms and hurricanes;" and says, "This confirms what I have said in my foregoing discourse, and seems evidently to prove, that the fire which makes vulcano's comes not from the bottom of mountains, but from the tops, or at least from a very little depth; and that the hearth (or floor) of the fire is not far from the summit of the vulcano's; for, if this was not the case, great winds could not contribute to their conflagration." And this, in general, is a corroborative proof of my whole hypothesis. For there can be no great fire in the earth, where there is no great conveyance of air.

We have one vulcano in the cold region of Iceland, and there is sometimes an earthquake there; but, in the countries of that northern latitude, and those of lesser, 'tis obvious in all history, that earthquakes are less frequent than in the more southern. Therefore 'tis easy, and very natural to conclude, from all considerations weighed together, that these vulcano's help to put the earth about them, into that vibratory state and condition of electricity, which is the requisite in my hypothesis, and by that means only, promote a frequency of earthquakes there.