Michael Faraday found that the magnetic force of the earth could induce electrical currents in metallic bodies in motion. Building on this idea, Charles Delezenne in France introduced an earth inductor of this sort in 1844.
This example belonged to the U.S. Military Academy at West Point and dates from the early 1870s. The inscription reads "HAWKINS & WALE MAKERS STEVENS INSTITUTE HOBOKEN, N.J.'
Ref: Charles Delezenne, "Notions élémentaire sur les phénoménes d'induction," Mémoires de la Societé; des Sciences de Lille 23 (1844): 1-132, on 109-120.
Adolphe Ganot, Elementary Treatise on Physics (London, 1867), pp. 701-702.
James W. Queen & Co., Priced and Illustrated Catalogue of Physical Instruments (Philadelphia, 1888), p. 106.
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