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Volume 10, No. 1, November 1997

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Joseph Henry, Radio Pioneer

In Joseph Henry's Own Words

The 1859 Experiment


Joseph Henry used an elevated antenna more than twenty years before Loomis. He sent signals between a tuned transmitter and receiver nearly fifty years before Lodge or Hertz. He invented a magnetic detector sixty years before Marconi­well, just kidding about that one. But it was magnetic, and it registered impulses from thunderstorms eight miles away.

So why is Joseph Henry's name forgotten with regards to radio history, with but a few exceptions to this neglect? In a biographical article in the January 1926 Bell System Technical Journal, Bancroft Gherardi and Robert W. King considered this question.

Henry's work contained the germ of yet another important discovery. Some of his experiments on induction by Leyden jar discharges involved the transmission of electric force without wires through distances as great as two hundred feet, and through the floors and walls of buildings. And in similar experiments in which he observed the effects of lightning flashes in place of sparks from a Leyden jar, he found that he could get the lightning to magnetize needles up to a distance as great as eight miles. This was about 1842. Here we have the earliest evidence of ether waves of the type that the radio engineer employs (pp. 9-10).

Gherardi and King surmised that the significance of Henry's experimentation had not been recognized earlier because that required "much fuller investigation" into radio technologies. But they also speculated that "had Henry not been called to other work, the world might have possessed a wireless telegraph capable of sending messages over substantial distances many years before it did."

Henry described this work briefly in what was issued posthumously in 1880 as the "Memorial of Joseph Henry" and subsequently republished as Volume 21 of the Smithsonian Miscellaneous Collections in 1881. Of course at that time it was just an interesting observation from forty years before, hardly worth expanding on, since radio didn't yet exist.

Perhaps the best way to appreciate just what Henry did in 1841 or 1842 is to read his account, published in 1860, and reprinted below. This was carefully buried in the Report of the Commissioner of Patents for 1859, Agricultural Section, in a lengthy paper on Meteorology, part V in a series begun in the 1855 Report (pp. 477-478). Charles Alfred Coulson asserts in Joseph Henry: His Life and Work (1950) that "scarcely anyone but his more intimate friends" read Henry's account, but it might be noted that 300,000 copies of this book were printed for distribution by members of Congress.

Granted, it takes some creative interpretation to credit Joseph Henry with transmitting and receiving intelligence by radio in 1842. But as noted earlier, the germ of the idea was there, and Henry certainly anticipated some later discoveries. In addition, who is to say that Loomis didn't read the 1859 Report and start thinking?


Alan S. Douglas has worked for more than thirty years for Benthos, Inc., makers of underwater research equipment. Recently, one of the firm's vehicles photographed a warship from Benedict Arnold's fleet at the bottom of Lake Champlain. Douglas's publications on radio and electronics history include three volumes of Radio Manufacturers of the 1920s and many journal and magazine articles, placed in periodicals ranging from the IEEE Spectrum to club bulletins.


Editors' note: Henry described the roof of his residence with relative precision, insofar as it pertained to his experiment: a "tinned iron. . . in the condition of an insulated plate, on account of the imperfect conduction of the wood and brick-work which intervened between it and the ground." Do you ever wonder if tin roofs, corks, and gimlet holes in window frames will again be instruments for conducting state-of-the art, technical experiments?


Illustration of Henry from: Cyrus F. Brackett, et al, Electricity in Daily Life: A Popular Account of the Applications of Electricity to Every Day Uses (New York: Charles Scribner's Sons, 1893), p. 37.