Image is of Joseph Henry's Oscillating Electromagnet Motor, 1830, Smithsonian Institution Archives, negative number 46,797-E.
The article Henry published on this invention, including an illustration of it, can be found at http://biodiversitylibrary.org/page/9077323. Minutes of the Albany Institute's April 25, 1831, meeting, which appear in The Papers of Joseph Henry, Vol. 1, p. 338, appear to reference a demonstration of Henry's motor.
"On a Reciprocating Motion Produced by Attraction and Repulsion." American Journal of Science, Vol. 20, July 1831, pp. 340-33. Reprinted in Scientific Writings of Joseph Henry. Smithsonian Miscellaneous Collections, Vol. 30. Washington, D.C.: Smithsonian Institution, 1887, pp. 54-57.
Moyer, Albert. Joseph Henry: The Rise of an American Scientist. Washington, D.C.: Smithsonian Institution Press, 1997, pp. 72-73.
Reingold, Nathan, ed. The Papers of Joseph Henry, The Albany Years, December 1797 - October 1832, Vol. 1. Washington, D.C.: Smithsonian Institution Press, 1972, p. 338.
Summary:
Joseph Henry demonstrates an "electro-magnetic machine" powered by the continuous reversal of polarity through magnets connected to two batteries. The batteries are wired to two vertical magnets which alternately attract and repel the ends of an electromagnet positioned in between them, making the electromagnet rock back and forth at 75 vibrations per minute. He publishes this discovery in Silliman's American Journal of Science in July 1831. In 1846, Henry will become the first Secretary of the Smithsonian Institution.
