Letter To Monsieur Dubourg 10 March 1773 On The Analogy Between Magnetism And Electricity From Memoirs Of The Life And Writings Of Benjamin Franklin

Benjamin Franklin writes about "the magnetism which seems produced by electricity" stating that his "real opinion is, that these two powers of nature have no affinity whatever with each other, and that the apparent production of magnetism is purely accidental." Franklin lists and describes ten arguments supporting his suppositions about the true nature of "magnetic fluid."

Benjamin Franklin writes about problems with glass used for the Leyden jar experiment into the nature and properties of electricity. He offers conjectures about various imperfections in the glass that might be the cause of failures in the experiment.

Benjamin Franklin uses a reference to persons killed by lightning as a springboard to speculate about "the doctrines of life and death, in general." He writes about toads remaining buried alive in sand "till the sand becomes petrified," and relates having seen apparently lifeless flies revived after having been transported across the Atlantic in a bottle of wine. Franklin then concludes "I wish it were possible, from this instance, to invent a method of enbalming drowned persons, in such a manner that they might be recalled to life at any period, however distant; for, having a very ardent desire to see and observe the state of America an hundred years hence, I should prefer to an ordinary death, the being immersed in a cask of Madeira wine, with a few friends, till that time, to be recalled to life by the solar warmth of my dear country!"

Benjamin Franklin responds to an inquiry about the possibility of using electricity to tenderize meat with his speculations about the possibilities. He cautions that animals killed by lightning are known to putrefy more quickly than otherwise, but outlines a method for killing poultry by electric shock in order to make the flesh more tender. He concludes with the further caution that since the amount of electricity he suggests is "capable of giving a very violent shock, the operator must be very circumspect, lest he should happen to make the experiment on his own flesh, instead of that of the fowl."

Benjamin Franklin writes his conjectures about the internal composition and structure of the earth, being quite certain from observable surface changes that the interior is not a solid but a dense fluid. He turns then to magnetism. Franklin supposes that the whole earth is one large magnet, and that since "the fluid of magnetism perhaps exists in all space," someone on a journey "from star to star" could be guided by a compass. He concludes with an apology for having "permitted myself to wander a little in the wilds of fancy" but offers the excuse that in his present circumstances he is not able to study scientific matters with experimentation and observation.

Benjamin Franklin comments on the results of an electricity experiment conducted by Ingenhausz.

Benjamin Franklin writes from London to Monsieur Dubourg in reply to the latter's remarks about a new method of treating smallpox. Franklin does not like the cold water bath which was then in vogue. He describes instead his own practice of sitting naked in his room every morning for 30-60 minutes after awakening in order to "bathe" in the cold air. Of this air bath, Franklin writes that "at least it does not injure my health, if it does not in fact contribute much to its preservation."

Benjamin Franklin writes from Philadelphia posing a series of speculative questions about the earth's magnetic field, about possible prehistoric changes in the earth's magnetic poles, about the internal structure of the earth, and about what effect that structure might have on sounds produced by earthquakes.

Benjamin Franklin, writing from Paris, gives his brief reactions to reported experiments by Volta that, Franklin says, appear to replicate the Leyden jars. He questions whether the electric charge can, indeed, be preserved for years, as claimed.

Benjamin Franklin explains his theory of positively and negatively charged clouds, and describes an experiment designed to investigate the same.