Since I had the honour to lay before the Society, in the spring, my thoughts upon earthquakes: we have had many further opportunities of reflecting upon that most awful, and hitherto unusual appearance. An earthquake was felt at Eastwell in Kent, on monday march 12, and on sunday, march 18, at Portsmouth, the Isle of Wight, Southampton, and along the coast of Sussex, the isles of Guernsey, Jersey. April 2, a smart earthquake at Manchester, Liverpool, Taunton, Bath, Flint, Lancaster, Wrexham, reaching 40 miles north and south: 70 miles east and west. Since then at Rome, Naples, Leghorn; in the south of France, and at Pau under the Pyrenean mountains: Oporto, at S. Macaire in Guienne, Messina in Sicily, Munich in Bavaria, &c. &c. so that the year 1750, may rather be called the year of earthquakes, than of jubilee. For since February last, when they began with us at London; as far as I can learn, they have appear'd in many parts of Europe, Asia, Africa, and America. And have likewise revisited many counties in our own island, and at length, on the 30th of last september gave much the most extensive shock, we have seen here in our days.

It may be well expected, that these frequent visits, in themselves so very extraordinary, to us so rare, and that in one year, should keep up our attention: and as to my own part, induce one to reflect, on what I before offer'd concerning them; and be a sufficient apology for the present paper.

We have been acquainted, by those who remember it, that in the earthquake of nov. 1703, which happen'd in Lincolnshire, the weather was calm, close, gloomy, warm, and dry; in a degree highly unusual, at that season. And thus it has been with us, all the year. And from the numerous accounts we have receiv'd at the Royal Society, in the beginning, and ending of the year; where any mention is made of the weather; they all agree in the like particular. Which is consentaneous to what I remark'd, as the constant forerunner of earthquakes; and what prepares the earth's surface, for the electrical stroke: which I asserted to be the cause of them.

In may last, we had a paper read at the Royal Society, concerning the second earthquake felt by us at London, on the 8th of march. A shepherd belonging to Mr. Secretary Fox at Kensington (the sky being perfectly serene, and clear) was much surprised with a very extraordinary noise in the air, rolling over his head, as of cannon close by. He likewise thought, that it came from the north-west, and went to the south-east: a motion quite contrary, to what must have been the case, if it were really of cannon. This noise pass'd rushing by him; and instantly he saw the ground (a dry, and solid spot) wave under him, like the face of the river. The tall trees of the avenue, where he was, nodded their tops very sensibly, and quiver'd like a shaken spear. The flock of sheep immediately took fright, and ran all away together, as if dogs had pursued them. A great rookery in the place, were equally alarm'd, and after an universal clangor, flew away; no less than if chaced by hawks.

I was likewise inform'd, that in the same earthquake, a great parcel of hens, and chickens, kept at that time in Gray's-inn-lane, upon the shock, ran to the roost, affrighted. And the like was observ'd of pigeons. And in our last account of the earthquake from Northampton, 'tis remarked, that the birds in cages put their heads under their wings, as to hide themselves.

June 21, at the Royal Society, Mr. Jackson potter at Lambeth, gave an account of some boats, cobles and lighters in the river, at that time; the people in them seem'd to feel, as if a porpoise, or some great fish had heav'd and thump'd at the bottom of the vessels. This is sometimes the case of ships at sea, when all is perfectly calm: which seems evidently owing to an electrical impression on the water.

In the evening-post of june 23, we had a paragraph from Venice, that a terrible earthquake had been felt lately in the little rocky isle of Cerigo, in the Mediterranean, south of Morea. It threw down a great number of houses; and above 2000 of the inhabitants were buried in the ruins.

Another earthquake about that time, happen'd in Switzerland; which split a vast, rocky mountain; and an old castle wall of an immense thickness.

All these circumstances, and many more confirmed me in my former opinion. But since then, these wonderful movements have stalk'd round the globe: and again been lately felt in our own island; happily for us, to the terror only, of many thousand people: beside those concussions of this sort that appear'd in the western parts, in the more early time of the year.

I receiv'd a letter from my friend Maurice Johnson, Esq; the founder, and secretary of the Literary Society of Spalding; which has now subsisted these 40 years. He acquaints me, that on thursday, 23d of August last, an earthquake was very sensibly felt there, about seven o'clock in the morning; throughout the whole town and neighbourhood; and many miles round: but that it chiefly spread itself northward, and southward. He says, that for a fortnight before, the weather had been serene, mild, and calm. And one evening, there was a deep red aurora australis, covering the cope of heaven, very terrible to behold. This same shock was felt at Grantham, Stamford, and Milton by Peterborough; and generally at all the intermediate places: and from Spalding it fled northward, along the sea shore, to Boston: thence up Boston river, to Lincoln.

Since then, I had a letter from Mr. Alderman Taylor of Stamford, giving an account of another earthquake, that happen'd there, september 30, at 36 minutes after twelve o'clock at noon. He describes it thus. They were suddenly surprised with an uncommon noise in the air, like the rolling of large carriages in the streets, for about 20 seconds. At the same instant they felt a great shake, or snap, as he calls it; insomuch that it sensibly shook a punch-bowl, which was in his parlour, and made it ring. He says, it was perceiv'd of most of the people of Stamford, who generally ran out of their houses. At Oakham the chief town of Rutland, the congregation ran out of the church whilst the preacher was in the pulpit. All the towns round Stamford, were sensible of it: and at Peterborough, down to Wisbech.

Thus far the Alderman. But we have had many advices from all hands, at the first, and second meetings of the Royal Society, for the winter season; with further particulars relating to this great concussion. That it was felt at the same time, at Rugby in Warwickshire, and reach'd to Warwick, at Lutterworth, in Leicestershire: at Leicester, and round about. It extended itself to Coventry, Derby, Nottingham, Newark; then came eastward to Harborough, Towcester, Northampton, Rowel, Kettering, Wellingborough, Oundle, in Northamptonshire; Uppingham, Oakham in Rutland; Stamford, Bourn, Grantham, Spalding, Boston, and to Lincoln in Lincolnshire; Holbech, and all Holland in that county. Peterborough, Wisbech, in the isle of Ely; together with all the intermediate, and adjacent places. Then it passed over the whole breadth of Ely fen: was felt at Mildenhall, and reach'd to Calford by Bury in Suffolk, and the country thereabouts; of which we had notice from lady Cornwallis. An extent from Warwick to Bury of about 100 miles in length; and generally speaking, 40 miles in breadth. And this vast space was pervaded by this amazing motion, as far as we can get any satisfaction, in the same instant of time. They describe it, that the houses totter'd, and seem'd to heave up, and down: tho' it lasted but a few seconds. It was attended with a rushing noise, as if the houses were falling, and people were universally so affrighted, as to run out; imagining that their own, or their neighbours houses were tumbling on their heads. In the villages around, the people being generally at divine service, were much alarm'd: both with the noise, which exceeded all the thunder they had ever heard, beyond compare: and with the great shock accompanying; which was like somewhat, as they imagin'd, that rush'd against the church-walls, and roof. Some thinking the pillars crack'd, many that the beams of the roof were disjointed; and all, that the whole was falling. And happy were they that could get out first. Many people fancied, that nests of drawers, and cabinets, or the like heavy things, were fallen down above stairs: or that chimnies had broke thro' the roof of the house: or that some persons fell down stairs: and the like. Some perceived the crackling of inward wainscots or partitions: as Dr. Mortimer and I, observ'd in our first and second shocks at London. A few slates, tiles, and parts of chimneys fell from some houses: pewter, china, glasses and brass from shelves. A clock bell, chamber bell sometime struck: windows universally rattled, and the like circumstances of tremor.

In regard to circumstances, they were pretty similar throughout. Many people sitting in their chairs relate, that they and their chairs were several times sensibly lifted up and set down again. A stack of chimneys were thrown down in College-lane; a place retaining the memory of a sort of university once beginning at Northampton. The windows of houses rattled throughout the whole town: but no mischief done: in general it was frightful, and innocuous.

They fancied there, the motion of it, as they expressed it, to be eastward. In streets that run north and south, the houses on the east side of the way, were most affected. And Dr. Stonehouse's dwelling, the strongest in the town, was most sensibly shaken. So it was likewise observ'd, that churches were most subject to its violence. They thought too, that the motion seem'd rather horizontal, or lateral, than upward. Some counted the pulses distinctly, to the number of four: that the second, and third pulses were stronger, than the first, and fourth.

From all these various accounts, there was no sulphureous smell, or eruption; no fissures in the ground perceived. Yet several people were sick upon it: infinite numbers terribly affrighted, and as soon forgot the impression of it; or talk'd of it in a merry strain; as commonly with us at London. So little are the vulgar assessed, without something very sensible; and so soon is the sense of it worn out!

It was more evidently perceiv'd, by people standing; most, by those that were sitting: least, by such as were walking: and in upper stories of houses, more than in lower; or in cellars. Some coming down stairs, were in danger of being thrown forwards. Several sitting in a chair, and hearing the hollow, thundering noise, and thinking it was a coach passing by; when they attempted to get up, to see what it was, they were thrown back again in their chair. Some heard the wainscot crackle, Some sitting in their chairs leaning forwards, were thrown down on their hands, and knees. Some people heard the noise without feeling the shock: others felt the shock without hearing the noise. Some in a standing posture, were forc'd to lay hold on a table, to keep themselves from falling.

It was particularly remarked (as before observ'd) that birds in cages were sensibly affrighted; thrusting their heads under their wings. Mrs. Allicock of Loddington, Northamptonshire, a lady in child-bed, was so affected, that it caused her death. Mrs. Hardy, another lady in the same circumstance, and in the same county, likewise expired upon it, Some people felt a sudden shortness of breath, that they were forc'd to go out into the open air, it so affected the pulmonary nerves. Many were taken with head-achs, and other sicknesses.

These are, in general, the circumstances and observations made, at the time of these earthquakes; when we recollect ourselves, after the suddeness, and fright. Give me leave to make the following remarks therefrom.

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.

4ly, The former earthquake that happen'd at Grantham, Spalding, Stamford, (which towns lie in a triangle) took up a space which may, in gross, be accounted a circle of 30 miles diameter: the center of which is that great morass, called Deeping-fen. This comprehends 15 miles of that 30, in diameter: and where probably, the electrical impression was first made. Much the major part of Deeping-fen is under water in the winter time; underneath 'tis a perfect bog. Now it is very obvious, how little favorable such ground is, for subterraneous fires.

In the second earthquake, not only this country was affected again, but likewise a much larger space of the same sort of fenny ground, rather worse than the former: all Donnington-fen, Deeping-fen, Croyland-fen, Thorney-fen, Whitlesea-fen, Bedford level, and the whole extent of Ely-fen, under various denominations. This country, under the turf, abounds with subterraneous timber of all sorts; fir, oak, and brush-wood: and stags horns. Now and then they find a quantity of hazel nuts, crouded together on an heap. I have some of them. This is a matter common to all boggy ground over the whole globe, Such things are the ruins of the antediluvian world, washed down from the high country where they grew, were here lodg'd upon the subsiding of the waters, and by time are o'ergrown with the present turf. They that seek for any other solution of this affair, than the universal Noachian deluge, want to account for a general effect, by a partial cause: and shut their eyes, both to the plain history of this matter; and to the infinite, notorious demonstrations of it, from fossil appearances.

5ly, All this country, tho' underneath 'tis a watry bog, yet thro' this whole summer, and autumnal season (as they can have no natural springs in such a level) the drought has been so great on the superficies, that the inhabitants were oblig'd every day, to drive their cattle several miles, for watering. The drought was greater, than has been known in the memory of any one living. This shows how fit the dry surface was, for an electrical vibration. And we learn from hence, this important particular, that it reaches but very little below the earth's surface.

Mr. Johnson, in another letter which he wrote to me concerning the second earthquake observ'd at Spalding; says upon this occasion, he was obliged to scour his canal, and deepen it: that they came to a white, quicksand; which afforded to all the neighbourhood, excellent water in plenty.

In the gravelly soil of London; and where the two shocks were felt by us, in the beginning of the year; we know, there is not a house in the whole extent of this vast city, and all around it, but a spring of water is ready, upon digging a well, Whence we have much reason to believe, that the interior of the earth, is like a sponge soak'd in water. So that the only dry part is the superficies, which is the object, and the subject of that electric vibration; wherein, according to my sentiments, an earthquake consists.

This shews the mistake of the ancients, who fancying that earthquakes proceeded from subterraneous eruptions, built their prodigious temple of Diana at Ephesus, upon a boggy ground, to prevent such a disaster, The marshy part of Lincolnshire, being my native country, the adjacent fen, together with that in the isle of Ely, I have been perfectly acquainted with; from one end to the other, ever since I knew any thing. This vast extent of fenny level, from near Cambridge in the south, to near Horncastle in the north, is 70 miles in length. And when I perceiv'd, that it was, in whole, or in part, shaken by both the last earthquakes: I could not but see, that it was no less than a demonstration against the old notion of their cause.

6ly, Earthquakes are truly most violent, in a rocky country: because the shock is proportionate to the solidity of the matter electrify'd. So that rocks, cliffs, quarries, old castle walls, and strong buildings, are most obnoxious to the concussion. The isle of Cerigo was more liable, and more rudely handled by the late earthquake; both because it was an isle, and because it was rocky. So we must say of the late earthquake in Switzerland, that split the mountain, and the old castle wall. Whence Mr. Johnson in his second letter, says, it cracked a very strong brick-house in Gosberton by Spalding. Dr. Doderidge observes from Northampton that Dr. Stonehouse's dwelling being a very strong one, was most sensibly shaken. And throughout the whole compass of this great earthquake, we find, both the noise, the shock, and the terror was greatest at the churches, whose walls and bulk made more resistance than houses. And generally speaking, the churches throughout this whole extent have very fair, and large towers, and very many remarkable spires all of good stone, which no doubt quiver'd very much at top, if we could have discern'd it. This same vibration impressed on the water, meeting with the solid of the bottom of ships, and lighters, gives that thump felt thereon; just as in common electrifying, we feel the stroke upon the joints of our limbs chiefly. Yet of the millions of ordinary houses, over which it passed, not one fell. A consideration which sufficiently points out to us, what sort of a motion this was not, what sort of a motion it was, and whence deriv'd; not a convulsion of the bowels of the earth, but an uniform vibration or undulation of its surface, aptly thought like that of a musical string: or what we put a drinking glass into, by rubbing one's finger over the edge; which yet brought to a certain pitch, breaks the glass; undoubtedly an electric repulsion of parts. And from this remarkable similarity in the appearance of earthquakes we gather an invincible argument against the old opinion of their cause; for the tumult of subterraneous eruptions can have no possible place herein.

7ly, We find from all accounts, ancient and modern, that the weather preceding these shocks, was mild, warm, dry, serene, clear, frosty: what notoriously favours all our electrical experiments. This is particularly observ'd by Mr. Johnson and Mr. Smith, and other accounts. In the extensive shock of sunday march 18, along the Sussex coast, they take notice from Portsmouth, that the day was serene, warm, and dry, and that a shower of rain fell immediately before the shock. Mr. Bowman of Moulsey observ'd a shock there on may 24 last, and says, the air was perfectly serene, and clear. We very well know, that generally, all last winter spring, summer, and autumn, have been most remarkably of this kind of weather; more so, than has been observ'd in our memory; and have had all those requisites, appearances, and preparations, that notoriously cause electricity, that promote it, or that are the effects of it.

8ly, We find the blood-red australis aurora preceding at Spalding, as with us at London. At the time of the earthquake at Manchester this year, it accompanied it. And this year has been more remarkable than any for fire-balls, storms, wind, thunder, lightnings, and coruscations, almost throughout all England. A large ball of fire, with a long fiery tail on july 22, that passed over great part of England northward. Another seen over London, passing from west to east, in october. Coruscations were seen just before that extensive shock of 70 miles long felt from Lancaster to Wrexham, on april 2, last. Fire-balls more than one were seen in Rutland, and Lincolnshire: and particularly observ'd. And Mr. Smith from Peterborough writes, that a fire-ball was seen the morning of the earthquake, in the upper part of Northamptonshire. All these kind of meteors are rightly judg'd to proceed from a state of electricity in the earth and atmosphere: and how far they are actually concerned in causing earthquakes, time, and accurate observation must inform us.

9ly, Mr. Johnson in both his letters to me, on the first and second earthquakes, at Spalding, remarks particularly, of their effects being mostly spread to the north and south, and especially felt on the sea coast. We may observe, that such is the direction of Spalding river, which both conducts, and strengthens the electric vibration: conveying it along the sea-shore thence, up to Boston channel; and so up Boston river to Lincoln, as we discern, by casting our eye on a map.

We observe further, that the main of this second earthquake display'd its effects along, and between the two rivers, Welland and Avon: and that from their very origins, down to their fall into the sea. It likewise reach'd the river Witham, which directed the electric stream that way too, to Lincoln. For which reason, as there meeting the same coming from Boston, the shock was most sensibly felt. It reach'd likewise to the Trent at Nottingham, which convey'd it to Newark.

The first electrical stroke seems to have been made on the high ground above Daventry, in Northamptonshire; where the Roman camps are, made by P. Ostorius the proprÆtor. From thence it descended chiefly eastward, and along the river Welland, from Harborough to Stamford, Spalding, the sea: and along the river Avon, or Nen, to Northampton, Peterborough, Wisbech to the sea. It spread itself all over the vast level of the isle of Ely; further'd by very many canals, and rivers, natural, and artificial, made for drainage. It was still conducted eastward up Mildenhall river, in Suffolk, to Bury, and the parts adjacent. All this affair duly consider'd, is a confirmation of the doctrine I advanc'd on this subject.

10ly, I apprehend, it was not the noise in the air, as of many cannon let off at once, preceding the earthquake, that so much affrighted people, or affected the sheep, the rookery at Kensington, the hen and chickens in Gray's-inn-lane, the pigeons. It could not be barely the superficial movement of the earth, that disturb'd them all at once. I judge it to be the effect of electricity, somewhat like what causes sea sickness; such a sort of motion, as we are not accustomed to. So the earthquake affects all those of weak nerves, or that have nervous complaints; obnoxious to hysterics, colics, rheumatick pains in their joints; several women were seized with violent head-achs, before both the shocks we felt in London. It was this that gave the people a shortness of breath. Mr. Smith from Peterborough speaks of a person that found himself very sick upon it. This made the dog run whining about the room, seeking to get out: this made the fishes leap up in the pond at Southwark; like as the experiment of electrifying the fishes: it makes them sick. And this causes the birds in cages to hide their heads under their wings, because they cannot fly away. Which is commonly observ'd of them in Italy, and countries, where earthquakes are more frequent.

11ly, I observe, the shepherd at Kensington thought the motion of the earthquake, and the sound, was from the north-west to south-east; the like Mr. W. Smith from Peterborough. On the contrary, Mr. Byfield the scarlet dyer in Southwark, thought the noise came from the river below bridge, and went toward Westminster; where it rattled so, that he did not doubt, but that the abbey-church was beaten down.

Dr. Parsons took pains to find out the way of the motion of the earthquake, from the different position of people's beds; but from the contradictory answers given, he cou'd not obtain any satisfaction, as to that point. All this, and what was observ'd from Northampton, of the motion being thought by some, to be upward and downward; by others rather horizontal, or lateral: the counting the pulses, and the like, only points out to us the prodigious celerity, and the vibratory species of the motion of an earthquake. But far, very far is this from being owing to the tumultuous ebullition, the irregular hurry of subterraneous explosions.

12ly, How the atmosphere, and earth, are put into that electric and vibratory state, which prepares them to give, or receive the snap, and the shock, which we call an earthquake; what it is, that immediately produces it, we cannot say: any more than we can define, what is the cause of magnetism, or of gravitation; or how muscular motion is perform'd, or a thousand other secrets in nature.

We seem to know, that the author of the world has disseminated ethereal fire, thro' all matter, by which these great operations are brought about. This is the subtil fluid of Sir Isaac Newton, pervading all things: the occult fire diffused thro' the universe, according to Marsilius Ficinus the platonic philosopher, on the Timeus of his master. All the Platonists insist on an occult fire passing thro', and agitating all substance, by its vigorous and expansive motion.

Before them, Hippocrates writes in the same sense, I. de victÛs ratione, that this fire moves all in all. This ethereal fire is one of the four elements of the ancients. It lies latent, and dispersed thro' all the other three, and quiescent: till collected into a quantity, that over-balances the circumjacent; like the air crouded into a tempest: or till it is excited, by any proper motion.

This fire gives elasticity: and elasticity or vibration is the mother of electricity. We don't so much wonder at phosphorus arising from animal substances; for this fire is in water, and betrays itself to our senses, in salt water. Many a time when I have passed the Lincolnshire washes, in the night time; the horse has seem'd to tread in liquid flames. The same appearance is oft at the keel of a ship. Fire exists in water, says Pliny, as well as in human bodies. nat. hist. II. 107. Loaf sugar beaten in the dark is luminous. Many vegetables, as indian cane, and rotten wood the like, as Bartholin largely recites, de luce hominum c. 4. All electric bodies have this privilege: that is, they more easily discover it. Amber, gum lac, naptha, bitumens, some precious stones. My old friend Mr. Stephen Gray the father and great propagator of electricity, show'd me experiments therein, in the year 1705, then at Corpus Christi college in Cambridge. Afterward in the year 1719, he show'd by experiments before the Royal Society, that paper, ribbands, silk, sattin, cloth, shavings, linen, goldbeaters skin, and in short, almost all kind of substances discover electrical sparks of fire in the dark: especially when well warm'd before the fire, or in a cold, dry, nitrous air, and in a room where there is no company. This same quality is found in vacuo, as Dr. Desaguliers show'd before the Royal Society, march 31, 1720. He took an exhausted glass globe, and caused it to be turn'd round violently, in an engine: by rubbing the hand upon it, it was illuminated within side, with purple streams. This gave foreigners the idea of using a glass globe, in electrical experiments.

The operation of the ethereal fire is various, nay, infinite, according to its quantity, and degree of incitement, progress, hindrance, or furtherance. One degree keeps water fluid, says the learned bishop of Cloyne: another turns it into elastic air, and air itself seems nothing else, but vapors, and exhalations render'd elastic, by this fire.

This fame fire permeates, and dwells in all bodies; even diamond, flint, and steel. Its particles attract with the greatest force, when approximated. Again, when united, they fly asunder, with the greatest force, and celerity; it resists nothing quiescent, but when put into motion, it disdains all resistance. All this is according to the laws prescrib'd by the sovereign architect. This is the life, and soul of action, and reaction, in the universe. Thus has the great author provided against the native sluggishness of matter! light, or fire in animals, is what we call the animal spirits; and is the author of life, and motion. But we know not the immediate mode of muscular motion; any more than how, in inanimate matter, it causes the vibrations of an earthquake.

Of this fire, the excellent Manilius thus writes, who liv'd in the time of Augustus.

Astronom. I.

Which may thus be english'd.

13ly, The great question then with us, is how the surface of the earth is put into that vibratory and electric state, by heat and driness? we must needs acquit the internal of the earth from the charge of these superficial concussions. How then is the ethereal fire crouded together, or excited, so as to cause them; seeing in our ordinary electrical experiments, we make use of friction?

But that friction alone does not excite electricity, we know from the obvious experiment of flint and steel, where the suddenness of the stroke, and hardness of the matter does it. Another method of exciting it, is the letting off a number of great guns, which so crouds the ethereal fire together, as to electrify glass windows; observ'd by my friend the reverend Dr. Stephen Hales. The aurora borealis, australis, all kind of coruscations, meteors, lightning, thunder, fire-balls are the effects, and may reciprocally be the cause of electricity; but how in particular we know not. Come we to the animal world, we must needs assert, that all motion voluntary, involuntary, generation, even life itself: all the operations of the vegetable kingdom, and an infinity more of nature's works, are owing to the activity of this electric fire, the very soul of the material world. And in my opinion, 'tis this alone, that solves the famous question, so much agitated with the writers in medicine, about the heat of the blood. How these, how earthquakes are begun, propagated, we are yet to seek.

We may readily enough presume, that the contact between the electric, and the non-electric, which gives the snap, and the shock, must come from without, from the atmosphere. Perhaps by some meteor that crouds the ethereal fire together: which then flies off with that immense force that causes the earthquake. In the point of contact on the earth's surface, the same thing is done, perhaps, another time, by a shower of rain. Our thoughts upon this matter must needs be as immature, as they are novel. But we may readily conclude, that tho' the original stroke comes from the atmosphere, yet the atmosphere has no further concern in it: no aereal power, or change therein, can propagate itself so instantaneously, over so vast a surface, as 4000 miles square. Therefore the impetuous rushing noise in the air, accompanying the shock, is the effect, and not the cause. And all this is strongly confirm'd by this observation, that the barometer and thermometer receiv'd no change upon the earthquakes.

But surely, there is not a heart of flesh that is not affected with so stupendous a concussion! let a man estimate his own power, with that which causes an earthquake; and he will be persuaded, that somewhat more than ordinary is intended by so rare and wonderful a motion. That great genius Hippocrates, makes the whole of the animal oeconomy to be administred, by what we call nature. And nature alone, says he, suffices for all things, to animals: she knows herself, and what is necessary for them. We must extend this thought to the inanimate world. And can we deny then, that he here means a conscious and intelligent nature, that presides over, and directs all things, moves the ethereal spirit or fire, that moves all things: a divine necessity, but a voluntary agent, who gives the commanding nod, to what we commonly call nature, the chief instrument in the most important operations of the vast machine, as well as in the ordinary ones, particularly the human one: administring the whole oeconomy (as he says) without noise, unseen, unfelt. And this leads us,

14ly, Lastly, in regard to the spiritual use we ought to make of these extraordinary phÆnomena, or of our inquiries about them, I shall first observe, that we find abroad, several of these earthquakes this year have been very fatal. In the last we read of, at Philippopoli in Thrace, the whole city was destroyed, above 4000 inhabitants killed. At home, where above half a score separate concussions have been felt, there has not been one house thrown down, one life lost. This ought to inspire us with a very serious reflection about them; nor is it altogether unworthy of our remark, that they began with us in London, in february last: and after visiting the circle of the globe, at present, end with us.

2dly, We may observe, that if we did but read the works of Hippocrates, Plato and his followers; of Tully, Galen, and the like ethic writers of antiquity; whilst we study, and try the affections of matter; we should improve in philosophy, properly speaking: we should lift up our minds from these earthly wonders, and discern the celestial admonitions, they present to us.

The original meaning of the word philosophy, was rightly apply'd to moral wisdom. We who have advanc'd both the natural, and moral, should, as the ancients did, join them both together. By this means, we gather, the truth of the highest, and most excellent philosophy, to be found in those volumes of first antiquity, which we call sacred: and which, 'tis our peculiar, and inestimable happiness to possess. We should adore that divine light, which they hold forth to us. Especially in a country, where the principles of true religion are open, and undisguised: where the establish'd profession of it is rational, noble and lovely: worthy of the moral governor of the world; fit for him to enjoin: for us to practise, with pleasure and effect.

november 7, 1750.

W. Stukeley.

Read at the Royal Society, december 6.

FINIS.