makes the trouble of collecting in many cases exceed the value of the sum collected. Things that are, practicable in one country are not always so in another, where circumstances differ. Our duties are, however, generally so small as to give little temptation to smuggling. Believe me ever, my dear friend, yours most affectionately, B. FRANKLIN. MDIII TO MADAME HELVETIUS PHILADELPHIA, 23 April, 1788. I received and read with the greatest pleasure, my dear friend, the kind letter you were so good as to write to me with your own hand, c'est toute à fait charmante. It rejoiced me to hear that you continued well with your chères petites étoilles, and that you still have your friends about you. I often think of the happiness I so long enjoyed in the sweet society of you and them at Auteuil. When we meet in Paradise, as I trust we shall, the pleasures of that place will be augmented by our recollection of all the circumstances of our acquaintance here below. You have made my daughter very happy by the things you sent her. They are much admired. I continue as well as I have been for some years past, and if I live six months longer, I may hope for some leisure, so as to be able to converse more frequently by letter with my absent friends, having absolutely determined to engage no more in any public business after my three years' service as President shall expire. M. Paradise, the gentleman who will have the honor of delivering this letter, intends to reside some time in Paris, and acquaints me that he has ordered some cardinals to be frequently sent to him from his estate in Virginia, and that if any of them get to Paris alive you shall be sure to have one. He had the pleasure of seeing you formerly with me at Passy. Temple is at his terre, busy with his agriculture. Benjamin presents his respects. Our best wishes attend you and yours most devoutly. I am exceedingly obliged to the good abbés and M. Cabanis for their letters. The Guichats and Nouvelle Cométologie entertained my friends and me very much. I cannot write to them now, but must say with the debtor in the Gospel: Have patience with me and I will pay you all. Adieu, my very dear friend, and believe me ever, yours most affectionately, B. FRANKLIN. MDIV TO JAMES BOWDOIN READ AT A MEETING OF the AmeriCAN PHILOSOPHICAL SOCIETY, JANUARY 15, 1790 PHILADELPHIA, 31 May, 1788. DEAR SIR: I received your favors by Messrs. Gore, Hilliard, and Lee, with whose conversation I was much pleased, and wished for more of it; but their stay with us was too short. Whenever you recommend any of your friends to me you oblige me. I want to know whether your Philosophical So ciety received the second volume of our Transactions. I sent it, but never heard of its arriving. If it miscarried I will send another. Has your Society among its books the French work Sur les Arts et les Métiers? It is voluminous, well executed, and may be useful in our country. I have bequeathed it them in my will; but if they have it already I will substitute something else. Our ancient correspondence used to have something philosophical in it. As you are now more free from public cares, and I expect to be so in a few months, why may we not resume that kind of correspondence? Our much regretted friend Winthrop once made me the compliment that I was good at starting game for philosophers; let me try if I can start a little for you. Has the question, How came the earth by its magnetism? ever been considered? Is it likely that iron ore immediately existed when this globe was first formed; or may it not rather be supposed a gradual production of time? If the earth is at present magnetical in virtue of the masses of iron ore contained in it, might not some ages pass before it had magnetic polarity? Since iron ore may exist without that polarity, and by being placed in certain circumstances may obtain it from an external cause, is it not possible that the earth received its magnetism from some such cause? In short, may not a magnetic power exist throughout our system, perhaps through all systems, so that if men could make a voyage in the starry regions, a The American Academy of Arts and Sciences.-EDITOR. compass might be of use? And may not such universal magnetism, with its uniform direction, be serviceable in keeping the diurnal revolution of a planet more steady to the same axis? Lastly, as the poles of magnets may be changed by the presence of stronger magnets, might not, in ancient times, the near passing of some large comet, of greater magnetic power than this globe of ours, have been a means of changing its poles, and thereby wrecking and deranging its surface, placing in different regions the effect of centrifugal force, so as to raise the waters of the sea in some, while they were depressed in others? Let me add another question or two, not relating indeed to magnetism, but, however, to the theory of the earth. Is not the finding of great quantities of shells and bones of animals (natural to hot climates) in the cold ones of our present world, some proof that its poles have been changed? Is not the supposition, that the poles have been changed, the easiest way of accounting for the deluge, by getting rid of the old difficulty how to dispose of its waters after it was over? Since, if the poles were again to be changed, and placed in the present equator, the sea would fall there about fifteen miles in height, and rise as much in the present polar regions; and the effect would be proportionable, if the new poles were placed anywhere between the present and the equator. Does not the apparent wreck of the surface of this globe, thrown up into long ridges of mountains, with strata in various positions, make it probable that its internal mass is a fluid; but a fluid so dense as to float the heaviest of our substances? Do we know the limit of condensation air is capable of? Supposing it to grow denser within the surface, in the same proportion nearly as it does without, at what depth may it be equal in density with gold? Can we easily conceive how the strata of the earth could have been so deranged, if it had not been a mere shell supported by a heavier fluid? Would not such a supposed internal fluid globe be immediately sensible of a change in the situation of the earth's axis, alter its form, and thereby burst the shell, and throw up parts of it above the rest? As, if we would alter the position of the fluid contained in the shell of an egg, and place its longest diameter where the shortest now is, the shell must break; but would be much harder to break, if the whole internal substance were as solid and hard as the shell. Might not a wave, by any means raised in this supposed internal ocean of extremely dense fluid, raise in some degree, as it passes, the present shell of incumbent earth, and break it in some places, as in earthquakes? And may not the progress of such wave, and the disorders it occasions among the solids of the shell, account for the rumbling sound being first heard at a distance, augmenting as it approaches, and gradually dying away as it proceeds? A circumstance observed by the inhabitants of South America in their last great earthquake; that noise coming from a place some degrees north of Lima, and being traced by inquiry quite down to Buenos Ayres, proceeded regularly from north to south at |