Econlib

The Library

Other Sites

 Front Page arrow Titles (by Subject) arrow CCCCXXXIX: TO JOSEPH PRIESTLEY - The Works of Benjamin Franklin, Vol. V Letters and Misc. Writings 1768-1772

Return to Title Page for The Works of Benjamin Franklin, Vol. V Letters and Misc. Writings 1768-1772

Search this Title:

Also in the Library:

Subject Area: Political Theory

CCCCXXXIX: TO JOSEPH PRIESTLEY - Benjamin Franklin, The Works of Benjamin Franklin, Vol. V Letters and Misc. Writings 1768-1772 [1904]

Edition used:

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. V (Letters and Misc. Writings 1768-1772).

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.


CCCCXXXIX

TO JOSEPH PRIESTLEY

London, 4 May, 1772.

Dear Sir:—

I think with you that there cannot be the least occasion for my explaining your method of impregnating water with fixed air to Messrs. Banks and Solander, as they were present, and I suppose are as well acquainted with it as myself; however, I shall readily do it if they think it necessary. I am glad you intend to improve and publish the process.

You must go half an inch farther with your spark to exceed what I showed here with my Philadelphia machine in 1758, to Lord Charles Cavendish and others, who judged them to be nine inches. My cushion was of buckskin, with a long damp flap, and had a wire from it through the window down to the iron rails in the yard; the conductor of tin four feet long and about four inches diameter. So powerful a machine had then never been seen in England before, as they were pleased to tell me. A machine was made from mine for Mr. Timmer, and was afterwards in the possession of Lord Morton. A more convenient construction I have never since seen, except that of yours. I intend soon to repeat Baretti’s experiments, being provided with the requisites, and shall let you know the result.

I should be glad to see the French translation of your book. Can you conveniently lend it to me when you have perused it? I fancy it was translated at the request of Abbé Nollet by a friend and disciple of his; as I know there was one (whose name I have forgotten) that used to translate for him extracts of English electrical books.

The Abbé’s machine was a very bad one, requiring three persons to make the smallest experiment; one to turn the great wheel, and one to hold hands on the globe. And the effect after all was but weak. De Lor had a similar one, and invited me to see him exhibit to the Duchess of Rochefoucauld; but, the weather being a little warm, he could perform nothing, scarce obtaining a spark.

This inconvenience must have occasioned his making fewer experiments, and of course his not being so easily convinced. M. Le Roy however, got early possession of the truth, and combated for it with Nollet; yet I think the Academy rather favored the latter. Le Roy will, I suppose, now confute this translator, for I have just seen a letter of his to Mr. Magalhaens, thanking him for sending so excellent an electrical machine to France (it is one of the plate ones), which he has improved so as to produce the positive and negative electricities separately or together at the same time. “De façon,” says he, “qu’on peut faire toutes les expériences possibles sur l’une ou l’autre de ces deux électricités. Enfin on étoit si eloigné de connoître les phénomènes de ces deux électricités ici, faute de machines commodes de les demontrer, que beaucoup des gens ont été étonnés de voir avec quelle évidence ils établissent la distinction des ces deux électricités,” &c. This letter is of the 5th instant.

My best wishes attend you and yours. I am ever, with great respect, my dear friend,

Yours most sincerely,

B. Franklin.