Front Page Titles (by Subject) LXXXIII: TO JARED ELIOT - The Works of Benjamin Franklin, Vol. II Letters and Misc. Writings 1735-1753
Return to Title Page for The Works of Benjamin Franklin, Vol. II Letters and Misc. Writings 1735-1753
The Online Library of Liberty
A project of Liberty Fund, Inc.
LXXXIII: TO JARED ELIOT - Benjamin Franklin, The Works of Benjamin Franklin, Vol. II Letters and Misc. Writings 1735-1753 
The Works of Benjamin Franklin, including the Private as well as the Official and Scientific Correspondence, together with the Unmutilated and Correct Version of the Autobiography, compiled and edited by John Bigelow (New York: G.P. Putnam’s Sons, 1904). The Federal Edition in 12 volumes. Vol. II (Letters and Misc. Writings 1735-1753).
About Liberty Fund:
Liberty Fund, Inc. is a private, educational foundation established to encourage the study of the ideal of a society of free and responsible individuals.
The text is in the public domain.
Fair use statement:
This material is put online to further the educational goals of Liberty Fund, Inc. Unless otherwise stated in the Copyright Information section above, this material may be used freely for educational and academic purposes. It may not be used in any way for profit.
TO JARED ELIOT
Philadelphia, 24 December, 1751.
I wrote you at large by my son, in answer to your former favors, and sent you an extract from Mr. Collinson’s letter, who much admires your Tracts on Husbandry. Herewith you will receive a manuscript of a friend of Mr. Collinson’s, and a printed book; which you may keep till spring, and then return it to me. I believe they will afford you pleasure.
I send you also enclosed a letter from my friend John Bartram, whose Journal you have read. He corresponds with several of the greatest naturalists in Europe, and will be proud of an acquaintance with you. I make no apologies for introducing him to you; for, though a plain and illiterate man, you will find he has merit. And since for want of skill in agriculture I cannot converse with you pertinently on that valuable subject, I am pleased that I have procured you two correspondents who can.
I am glad you have introduced English declamation into your college. It will be of great service to the youth, especially if care is taken to form their pronounciation on the best models. Mr. Whittlesey, who was lately here, will tell you that we have little boys under seven, who can deliver an oration with more propriety than most preachers. It is a matter that has been too much neglected.
I am, dear Sir, yours affectionately,
TO JAMES BOWDOIN
read at the royal society, may 27, 1756
Philadelphia, 24 January, 1752.
I am glad to learn by your favor of the 21st past, that Mr. Kinnersley’s lectures have been acceptable to the gentlemen of Boston, and are like to prove serviceable to himself.
I thank you for the countenance and encouragement you have so kindly afforded my fellow-citizen.
I send you enclosed an extract of a letter containing the substance of what I observed concerning the communication of magnetism to needles by electricity. The minutes I took at the time of the experiments are mislaid. I am very little acquainted with the nature of magnetism. Dr. Gawin Knight, inventor of the steel magnets, has wrote largely on that subject; but I have not yet had leisure to peruse his writings with the attention necessary to become master of his doctrine.
Your explication of the crooked direction of lightning1 appears to me both ingenious and solid. When we can account as satisfactorily for the electrification of clouds, I think that branch of natural philosophy will be nearly complete.
The air undoubtedly obstructs the motion of the electric fluid. Dry air prevents the dissipation of an electric atmosphere, the denser the more, as in cold weather. I question whether such an atmosphere can be retained by a body in vacuo. A common electrical phial requires a non-electric communication from the wire to every part of the charged glass; otherwise, being dry and clean, and filled with air only, it charges slowly and discharges gradually by sparks, without a shock; but, exhausted of air, the communication is so open and free between the inserted wire and surface of the glass, that it charges as readily, and shocks as smartly, as if filled with water; and I doubt not but that in the experiment you propose the sparks would not only be near straight in vacuo, but strike at a greater distance than in the open air, though perhaps there would not be a loud explosion. As soon as I have a little leisure, I will make the experiment and send you the result.
My supposition, that the sea might possibly be the grand source of lightning, arose from the common observation of its luminous appearance in the night, on the least motion; an appearance never observed in fresh water. Then I knew that the electric fluid may be pumped up out of the earth by the friction of a glass globe on a non-electric cushion; and that notwithstanding the surprising activity and swiftness of that fluid and the non-electric communication between all parts of the cushion and the earth, yet quantities would be snatched up by the revolving surface of the globe, thrown on the prime conductor, and dissipated in air. How this was done, and why that subtile, active spirit did not immediately return again from the globe into some part or other of the cushion, and so into the earth was difficult to conceive; but whether from its being opposed by a current setting upwards to the cushion, or from whatever other cause, that it did not so return was an evident fact. Then I considered the separate particles of water as so many hard spherules, capable of touching the salt only in points, and imagined a particle of salt could therefore no more be wet by a particle of water, than a globe by a cushion; that there might therefore be such a friction between these originally constituent particles of salt and water, as in a sea of globes and cushions; that each particle of water on the surface might obtain, from the common mass, some particles of the universally diffused, much finer, and more subtile electric fluid, and, forming to itself an atmosphere of those particles, be repelled from the then generally electrified surface of the sea, and fly away with them into the air. I thought, too, that possibly the great mixture of particles electric per se in the ocean water might, in some degree, impede the swift motion and dissipation of the electric fluid through it to the shores, &c. But having since found, that salt in the water of an electric phial does not lessen the shock; and having endeavoured in vain to produce that luminous appearance from a mixture of salt and water agitated; and observed, that even the sea-water will not produce it after some hours’ standing in a bottle; I suspect it to proceed from some principle yet unknown to us (which I would gladly make some experiments to discover, if I lived near the sea), and I grow more doubtful of my former supposition, and more ready to allow weight to that objection (drawn from the activity of the electric fluid, and the readiness of water to conduct), which you have indeed stated with great strength and clearness.
In the mean time, before we part with this hypothesis, let us think what to substitute in its place. I have sometimes queried, whether the friction of the air, an electric per se, in violent winds, among trees, and against the surface of the earth, might not pump up, as so many glass globes, quantities of the electric fluid, which the rising vapors might receive from the air, and retain in the clouds they form; on which I should be glad to have your sentiments. An ingenious friend of mine supposes the land clouds more likely to be electrified than the sea clouds. I send his letter for your perusal, which please to return to me.
I have wrote nothing lately on electricity, nor observed any thing new that is material, my time being much taken up with other affairs. Yesterday I discharged four jars through a fine wire, tied up between two strips of glass; the wire was in part melted, and the rest broke into small pieces, from half an inch long to half a quarter of an inch. My globe raises the electric fire with greater ease, in much greater quantities, by the means of a wire extended from the cushion to the iron pin of a pump-handle behind my house, which communicates by the pump-spear with the water in the well.
By this post I send to Dr. Perkins, who is curious in that way, some meteorological observations and conjectures, and desire him to communicate them to you, as they may afford you some amusement, and I know you will look over them with a candid eye. By throwing our occasional thoughts on paper, we more readily discover the defects of our opinions, or we digest them better, and find new arguments to support them. This I sometimes practise; but such pieces are fit only to be seen by friends.
I am, with great respect, &c.,