THE PHILOSOPHY OF EARTHQUAKES, Natural and Religious. OR

An Inquiry into their Cause, and their Purpose.

O Vita philosophia dux, virtutum indagatrix, expultrixque vitii!

Cicero.

By WILLIAM STUKELEY, M.D. Rector of St. George's, Queen-Square: Fellow of the College of Physicians and Royal Society:

The SECOND EDITION. To which is added, PART II. on the same Subject.

LONDON: Printed for C. Corbet over-against St. Dunstan's Church, Fleetstreet.

MDCCL.

To the Reader.

The substance of the philosophical part of this discourse was delivered at twice to the Royal Society, on March 15, and 22: The theological, in my own church. I could not refuse the solicitation of my friends, hearers in both places, to print it. I wish my intention, in the compliance, may any ways prove successful; to show, how vain, and unmeaning, are all our philosophical inquiries, when destitute of their true view; to lead us into the more engaging paths of religion. That, from speculation of material causes, we may become adepts in that wisdom which is from above. Otherwise, like Epicurus, and the ancient heathen philosophers, we barter away our immortal part, for a curiosity, that amuses us to no good purpose. Mean are these objects of our senses to be accounted, in comparison of our spiritual natures, to which our principal regard is due! For we must rightly say with Job: Lo, these are parts of God's ways, but how little a portion is heard of him? and the thunder of his power, who can understand?

TO Martin Folkes, Esq; LL.D. President of the Royal Society.

March 26, 1750.

When so great and unusual a phenomenon, as an earthquake, and that repeated, happens among us; it will naturally excite a serious reflection in everyone that is capable of thinking. And we cannot help considering it, both in a philosophical and a religious view. Any mind will take the alarm when we perceive a motion that affects the earth, that bears the whole city of London, and some miles round it. And at the same time while it gives us so sensible a shake, so gently sets us down again; without damage to any buildings, and without a life lost.

'Tis hard to say, which is the greater wonder. But alas in the works of nature, there are no degrees of great, and little; comparisons are incompatible. We indeed are more affected with what seems great in our own apprehensions: I would rather say, what is rare and unusual. An omnipotent power admits of no distinctions. And when prodigious effects are produc'd from causes imperceptible, it rightly claims our most serious attention, as well as wonder. Nor need we lose sight of the theological purpose of these amazing alarms; whilst we endeavor to find out the philosophy of them.

Among all the appearances of nature, which are the subject of the inquiries of the Royal Society, none more deserves the regard of a contemplative mind. And among the very numerous accounts received there, from all quarters, being only Observations upon the manner of it, and its extent: I judg'd, it became us to inquire into the cause of so extraordinary a motion: of which we could not form a proper idea; had we not repeatedly seen, and felt it.

The moderns have not improv'd upon the opinions of the ancients, in this matter; any further than by the fancied analogy of some chymical experiments. But these chymical experiments, and all sorts of explosions by gun-powder, and the like, are to me a very unsatisfactory solution they are merely artificial compositions, which can have nothing similar in the bowels of the earth, and they produce their effects by violence, by rending and tearing, by a solutio continui. This is indeed too often the case of earthquakes, but that is a partial degree, not at all equivalent to the compass of the shock; and is very far from being the constant concomitant of an earthquake. Quite the contrary. Innumerable such happen, when there is no breach of the surface; and of these three or four which we have now felt, nothing of it has appear'd. But the immensity of the vibration of the earth which shook every house in London, with impunity, and for twenty miles round, can never, in my apprehension, be owing to so unbridled a cause, as any subterraneous vapours, fermentations, rarefactions, and the like; the vulgar solution. Nor does the kind of motion, which I discern in an earthquake, in any sort agree with what we should expect from explosions.

In order then to proceed with some degree of certainty, in our inquiry after the cause of earthquakes, it will be useful, in the first place, to set in one view, the general appearances remarkable therein; the most usual concomitants: As we can collect them from our own observation, or from the relations and writings of others.

Circumstances.

I. That earthquakes always happen in calm seasons, in warm, dry, sultry weather; or after a dry, frosty air.

II. That they are felt at sea, as well as land, even in the main ocean; and at that time, the sea is calm.

III. That earthquakes differ very much in magnitude. Some shake a very large tract of country, at the same instant of time; nay, sometime extend to very many countries, separated by mountains, seas, lakes, the ocean.

IV. That earthquakes differ very much in the quantity, of their vibratory motion: Whence in some, tho' largely extended, they are innocuous; in others, both small and great, they lay all in ruin and destruction.

V. That a hollow, thundering, unusual noise accompanies them, or rather seems to preceed the shock; which rolls in the air like the noise of cannon.

VI. That they are felt more sensibly in the upper story of houses than in the lower.

VII. That the shock is more violent upon more solid buildings, churches, castles, and stone-houses, than upon those of slighter materials.

VIII. That many people find themselves sick at stomach, with headake, and pains in their joints, and the like, which sometime lasts for the day after, or longer.

IX. That earthquakes generally happen to great towns, and cities, and more particularly to those that are situate on the sea.

X. That earthquakes do not cause any damage to springs and fountains; but the water in wells becomes foul for a short time.

XI. That they are more frequent in the neighboring countries of a vulcano.

This last circumstance, in my opinion, has led all inquirers in this question, out of the true path; therefore I propose in the ensuing paper.