1. For Henry's appointment, see Nathan Reingold, ed., The Papers of Joseph Henry, Vol. 1 (Washington: Smithsonian Institution Press, 1972), pp. 132-133. For the Albany Academy's curriculum and educational philosophy, see pp. 44-49 and Albert E. Moyer, Joseph Henry: The Rise of an American Scientist (Washington, Smithsonian Institution Press, 1997), pp. 26, 50-51. [Return to text.]

2. Joseph Henry, "On Some Modifications of the Electro-Magnetic Apparatus," Transactions of the Albany Institute, Vol. 1, pp. 22-24; reprinted in Scientific Writings of Joseph Henry, Vol. 1 (Washington: Smithsonian Institution, 1886), pp. 3-7. See Papers of Joseph Henry, Vol. 1, p. 201, and Moyer, Joseph Henry, pp. 59-60. For Henry's thoughts on the value of experimental demonstrations in scientific education, see his Albany Academy inaugural lecture, Papers of Joseph Henry, Vol. 1, pp. 176-178, and Moyer, Joseph Henry, pp. 46, 54, 56-57, 98. [Return to text.]

3. For Schweigger's work and publications, see Robert A. Chipman, "The Earliest Electromagnetic Instruments," Contributions from the Museum of History and Technology, Paper 38, Smithsonian Institution, United States National Museum Bulletin 240 (Washington: Smithsonian Institution, 1966), pp. 127-131. Henry could not have read Schweigger's original reports, which were in German; he refers to Jacob Green, Electro-Magnetism, Being an Arrangement of the Principal Facts hitherto Discovered in that Science (Philadelphia, 1827), p. 30. See Papers of Joseph Henry, Vol. 1, pp. 322-323. [Return to text.]

4. Henry, "On the Application of the Principle of the Galvanic Multiplier to Electro-Magnetic Apparatus, and Also to the Developement of Great Magnetic Power in Soft Iron, with a Small Galvanic Element," American Journal of Science and Arts 19 (January 1831): 401, reprinted in Scientific Writings of Joseph Henry, Vol. 1, p. 38. [Return to text.]

5. For Sturgeon's electromagnet, see W. James King, "The Development of Electrical Technology in the 19th Century: 1. The Electrochemical Cell and the Electromagnet," Contributions from the Museum of History and Technology, Paper 28, United States National Museum Bulletin 228, (Washington: Smithsonian Institution, 1962), p. 258 and Fig. 41. [Return to text.]

6. Henry, "On the Application of the Principle of the Galvanic Multiplier...," Scientific Writings, Vol. 1, pp. 39-45. [Return to text.]

7. For Henry's correspondence with Silliman about this paper (see note 4 above), see Papers of Joseph Henry, Vol. 1, pp. 301-303, 316-319. See also Moyer, Joseph Henry, pp. 62-67. [Return to text.]

8. Henry, "An Account of a Large Electro-Magnet, Made for the Laboratory of Yale College," American Journal of Science and Arts 20 (April 1831): 201-203, reprinted in Scientific Writings, Vol. 1, pp. 50-53, and reproduced in facsimile in James E. Brittain, ed., Turning Points in American Electrical History (New York: IEEE Press, 1977), pp. 27-29. For the correspondence about this magnet, see Papers of Joseph Henry, Vol. 1, pp. 316-321, 330-334. The magnet itself is preserved in the Electricity Collection of the Smithsonian Institution's National Museum of American History; its catalogue number is 181,343. [Return to text.]

9. For requests to Henry for electromagnets and information on their construction and management, see Papers of Joseph Henry, Vol. 1, pp. 320-321, 327-328, 345-346, 348-349, 380, 400-402, 416-417. For the construction of Cleaveland's magnet, see pp. 373, 375-378, 402-404, 413, 420-426, 432-433. The core of this magnet (the windings have been removed) is on display in the exhibition, "Edison: Lighting a Revolution," in the National Museum of American History; its catalogue number is 315,390. [Return to text.]

10. "Statement of Prof. Henry, in relation to the History of the Electro-magnetic Telegraph," Annual Report of the Board of Regents of the Smithsonian Institution ... for the Year 1857 (Washington: William A. Harris, Printer, 1858), p. 105. [Return to text.]

11. American Journal of Science and Arts 20 (July 1831): 340-343; reprinted in Henry, Scientific Writings, Vol. 1, pp. 54-57; reproduced in facsimile in Brittain, ed., Turning Points in American Electrical History, pp. 31-34. [Return to text.]

12. King, "The Development of Electrical Technology," pp. 260-261. For a detailed account and assessment of the earliest devices for producing motion by electromagnetism, including Henry's, see Brian Gee, "Electromagnetic Engines: Pre-Technology and Development Immediately Following Faraday's Discovery of Electromagnetic Rotations," History of Technology, Vol. 13, 1991, pp. 41-72. [Return to text.]

13. Papers of Joseph Henry, Vol. 1, p. 376. [Return to text.]

14. Papers of Joseph Henry, Vol. 2, pp. 161-164. [Return to text.]

15. This device is on display in the lobby of Jadwin Hall, Princeton University. See Malcolm MacLaren, The Rise of the Electrical Industry During the Nineteenth Century (Princeton, N.J.: Princeton University Press, 1943), pp. 21-22 and Fig. 14. MacLaren dates the Princeton motor to 1837, but gives no evidence. For many years it was at the Smithsonian Institution, where it was given the number 180,928. [Return to text.]

16. William Ritchie, "Experimental Researches in Electro-Magnetism and Magneto-Electricity," Philosophical Transactions of the Royal Society of London, Vol. 123, 1833, pp. 313-321. [Return to text.]

17. Papers of Joseph Henry, Vol. 2, pp. 162-163, 195, 446-448. [Return to text.]

18. Proceedings of the American Philosophical Society, Vol. 1, p. 301, reprinted in Scientific Writings, Vol. 1, p. 189. For still another modification by Henry to his engine, see Moyer, Joseph Henry, p. 73. [Return to text.]

19. Daniel Davis, Jr., Davis's Descriptive Catalogue of Apparatus and Experiments,... (Boston, 1838), pp. 27, 30. [Return to text.]

20. Charles G. Page, "Experiments in Electro-Magnetism," American Journal of Science and Arts 33 (No. 1, January 1838): 118-120. [Return to text.]

21. Davis, Davis's Manual of Magnetism, ... (Boston, 1848, 2nd edition), pp. 211-213, fig. 146. [Return to text.]

22. [Charles G. Page], History of Induction: The American Claim to The Induction Coil and its Electrostatic Developments (Washington, 1867), pp. 121-122. [Return to text.]