decisive: then your proposed solemn league and covenant will go better down, and perhaps most of our other strong measures be adopted. I am always glad to hear from you, but I do not deserve your favours, being so bad a correspondent. My eyes will now hardly serve me to write by night, and these short days have been all taken up by such variety of business that I seldom can sit down ten ninutes without interruption, God give you success I am, with the greatest esteem, Yours affectionately, B. FRANKLIN ол HE THEORY OF THE EARTH. SIX, TO ABSE SOULIAVE. Passy, September 22, 1782. 1 ESTOUN the papers with some corrections. I dia not find coal mines, under the calcareous rock in Derby shi.e.-1 only remarked, that at the lowest part of that rocky mountain, which was in sight, there were oyster shells mixed with the stone; and part of the high country of Derby being probably as uch above the level of the sea, as the coal mines of Whitehaven were below, it seemed a proof that there had been a great oouleversement in the surface of that island, some part of it having been depressed under the sea, and other parts, which had been under it, being raised above it. Such changes in the super ficial parts of the globe seemed to me unlikely to hap pen, if the earth were solid at the centre. I there Are imagined that the internal parts might be a fluid more dense, and of greater specific gravity than any of the solids we are acquainted with; which there 1re might swim in or upon that fluid. Thus the sur face of the globe would be a shell, capable of being roken and disordered by the violent movementi of fluid on which it rested. And, as air has been compressed by art so as to be twice as dense as water, in which case, if such air and water could be contained in a strong glass vessel, the air would be seen to take the lowest place, and the water to floa above and upon it; and, as we know not yet the degree of density to which air may be compressed, and M. Amontons calculated, that, its density increasing as it approached the centre in the same proportion as above the surface, it would at the depth of leagues, be heavier than gold, possibly the dense fluid occupying the internal parts of the globe might be air compressed. And as the force of expansion in dense air when heated, is in proportion to its density; this central air might afford another agent to move the surface, as well as be of use in keeping alive the central fires; though, as you observe, the sudden rare faction of water, coming into contact with those fires, may be an agent sufficiently strong for that purpose, when acting between the incumbent and the fluid on which it rests. If one might indulge imagination in supposing how such a globe was formed, I should conceive, that all the elements in separate particles, being originally mixed in confusion, and occupying a great space, they would as soon (as soon as the Almighty fiat ordained gravity, or the mutual attraction of cer ain parts, and the mutual repulsion of other parts, 10 xist) all move towards their common centre: tha the air being a fluid whose parts repel each other though drawn to the common centre by their gravity, would be densest towards the centre, and rarer a more remote; consequently, all bodies, lighter than the central parts of that air, and immersed in it, would recede from the centre, an rise till they arrive at that region of the air, which was of the saine specific gra vity with themselves, where they would rest; while other matter mixed with the lighter air, woula descend, and the two, meeting, would form the shell of the first earth, leaving the upper atmosphere nearly clear. The original movement of the parts towards their common centre would form a whirl there; which would continue in the turning of the new-formed globe upon its axis, and the greatest diameter of the shell would be in its equator. If by any accident afterwards the axis should be changed, the dense internal fluid, by aering its form, must burst the shell, and throw all substance into the confusion in which w find it. will not trouble you at present with my fancies concerning the manner of forming the rest of our system. Superior beings smile on our theories, and at our presumption in making them. I will just mention that your observation of the ferruginous nature of the lava, which is thrown out from the depths of our volcanoes, gave me great pleasure. It has long been a supposition of mine, that the iron contained in the substance of the globe has made it capable of becoming, as it is, a great magnet; that the fluid of magnetism exists perhaps in all space; so that there is a magnetical North and South, of the universe, as well as of this globe; and that if it were possible for a man to fly from star to star, he might govern his course by the coinpass; that it was by the power of this general magnetism this globe be ame a particular magnet. In soft or hot iron the fluid of magnetism is naturally diffused equally; when within the influence of a magnet, it is drawn to one end of the iron, made denser there and rarer at the other. While the iron continues soft and hot, it is only a temporary magnet if it cools or grows hard in that situation, it becomes a permanent one, the magnetic fluid not easily resuming its equilibrium. Perhap it may be owing to the permanent magnetism of this globe, which it had not at first, that its ax.s is at prø sent kept parallel to itself, and not liable to the changes it formerly suffered, which occasioned the rupture of its shell, the submersions and emersions of its lands The present polas and the confusion of its seasons. and equatorial diameters differing from each othe near ten leagues, it is easy to conceive, in case some rt power should shift the axis gradually, and place itnah the present equator, and make the new equator pane through the present poles, what a sinking of the what ters would happen in the present equatorial regions o and what a rising in the present polar regions; so that vast tracts would be discovered that now are under water, and others covered that now are dry, the wat rising and sinking in the differet extremes near five leagues! Such an operation as this possibly occasion ed much of Europe, and, among the rest, of the mountain of Passy, on which I live, and which composed of limestone, rock and sea shells, to abandoned by the sea, and to change its ancient cli mate, which seems to have been a hot one. The globe being now became a perfect magnet, we are perhaps. safe from any future change of its axis. But we are still subject to the accidents on the surface, which are occasioned by a wave in the interna! ponderous fluid and such a wave is produced by the sudden violent explosion you mention, happening from the junction of water and fire under the earth, which not only lifts the incumbent earth that is over the explo sion, but, unpressing with the same force the fluid under it, creates a wave that may run a thousand leagues, lifting, and thereby shaking successively, all the countries under which it passes. I know not whether I have expressed myself so clearly, as not to get out of your sight in these reveries. If they occasion any new inquiries, and produce a better hypothesis, they will not be quite useless. You see I have given a loose to imagination, but I approve much more your inethod of philosophising, which proceeds upon actual observation, makes a collection of facts, and concludes no farther than those facts wil warrant. In my present circumstances, that mod of studying the nature of the giove is out of my power and therefore I have permitted myself to wander a little in the wilds of fancy. With great esteem, 1 have the nonour to be, Sir, &c. B. FRANKLIN P. S. I have heard that chemists can by their rt decompose stone and wood, extracting a consideable quantity of water from the one, and air froin he other. It seems natural to conclude from this, hat water and air were ingredients in their originel omposition for men cannot make new matter of ny kind. In the same manner do we not suppose, hat when we consume combustibles of all kinds, and produce heat or light, we do not create the hea right, we only decompose a subs.ance which re eived it originally as a part of its composition let may thus be considered as originally in a fluid tate: but, attracted by trganized bodies in their rowth, becomes a part of the solid. Besides this, I can conceive that, in the first assemblage of the articies of this earth is composed, each brought its crtion of the loose heat that had been connected rithi and the whole, when pressed together, prolueed ne intenial fire which still subsists. LOOSE THOUGHTS ON THE UNIVER- Passy, June 25, 1784. UNIVERSAL space, as far as we know of it, seems t e filled with a subtle fluid, whose motion, or vibraion, is called light. This fluid may possibly be the same with that which, being attracted by and entering into other nore solid inatter, dilates the substance, by sepa. ating the constituent particles, and so rendering ome solids fluid, and maintaining the fluidity of |