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 The Foundations of Induction - 1826
Joseph Henry (1797 - 1878)

Joseph Henry
 (1797 - 1878

Joseph Henry’s discovery of self induction in 1832 was the first appearance of a major US discovery in electricity since Benjamin Franklin. 

Writes Henry: "I may however mention one fact which I have not seen noticed in any work ...when a small battery is moderately excited... if a wire thirty or forty feet long be used instead of the short wire, though no spark will be perceptible when the

Henry, Joseph. On the production of currents and sparks of electricity from magnetism. IN: American Journal of Science and Arts. Vol 22, No 1, July 1832

 connection is made, yet when it is broken by drawing one end of the wire from its cup of mercury, a vivid spark is produced."  

In these words Henry reported his observation of self induction, two years before Faraday and a few months after Faraday's seminal paper on mutual induction (which Henry acknowledges). The unit of inductance was subsequently called "Henry", and that of capacity, "Farad", after Faraday.

 It is this paper, not the 1834 paper referenced in Dibner 65, that describes the discovery of self-induction. Faraday reported self induction later, in Dec. 1834, (Exp Res, 1048). Wittaker attributes the discovery of self induction to Faraday (Exp. Res. 1048) but adds: " A similar observation had been made by Joseph Henry, and published in the Amer. Jour. Sci. xxii (1832), p. 408,"  

Relevant to the controversy between Faraday and Henry is the following statement by A D Bache, Secretary of the American Philosophical Society introducing an abstract of Henry in J Franklyn Inst. 1835 pp. 169-70 (H. Norman 1053): "A memoir on this subject has been since submitted to the Society, containing an extension of the subject, the primary fact in relation to which was observed by Professor Henry as early as 1832, and announced by him in the American Journal of Science. Mr. Faraday having recently entered upon a similar train of observations, the immediate publication of the accompanying is important, that the prior claims of our fellow countryman may not be overlooked."

 This is an extremely rare publication in this condition.

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