Joseph Henry, Radio Pioneer

Illustration of Joseph 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.
Illustration of Joseph 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.

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.

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?

In Joseph Henry’s Own Words

The next series of experiments . . . was on the induction from thunder clouds. For this purpose the tin covering of the roof of the house in which I resided was used as an inductive plate. A wire was soldered to the edge of the roof near the gutter, was passed into my study and out again through holes in the window-sash, and terminated in connection with a plate of metal in a deep well immediately in front of the house. By breaking the continuity of that part of the wire which was in the study, and introducing into the opening a magnetizing spiral, needles placed in this could be magnetized by a flash of lightning so distant that the thunder could scarcely be heard. The electrical disturbance produced in this case was also found to be of an oscillatory character, a discharge first passing through the wire from the roof to the well, then another in the opposite direction, and soon until equilibrium was restored. This result was arrived at in this case, as well as in that of the Leyden jar, before mentioned, by placing the same, or a similar needle, in succession, in spirals of greater and greater number of turns; for example, in a spiral of a single turn the needle would be magnetized plus, or in the direction due to the first and more powerful wave. By increasing the number of coils, the action of the second wave became dominant, so that it would more than neutralize the magnetism produced by the first wave, and leave the needle minus. By further increasing the number of turns, the third wave would be so exalted as to neutralize the effects of the preceding two, and so on. In the case of induction by lightning, the same result was obtained by placing a number of magnetizing spirals, of different magnetizing intensities, in the opening of the primacy conductor, the result of which was to produce the magnetization of an equal number of needles, plus and minus, indicating alternative currents in opposite directions.

Excerpt from “Memorial of Joseph Henry,” Smithsonian Miscellaneous Collections, Volume 21 (Washington, D.C., 1881), pp. 152-153.

1859 Experiment

Figure illustrated Joseph Henry's 1859 account of an experiment he had performed years earlier while at Princeton.
Figure illustrated Joseph Henry’s 1859 account of an experiment he had performed years earlier while at Princeton.

This figure illustrated Joseph Henry’s 1859 account of an experiment he had performed years earlier while at Princeton. In describing this component of his study of induction from clouds, Henry explained that “the inductive action of the electrical discharge in the heavens was exerted on the natural electricity of a surface of about 1,600 square feet [the tin roof], and a considerable portion of this passed down through the wire” that ran through his room to a ground. There, the “intensity of magnetism and the direction of the current were ascertained by presenting the end of the needle [hanging from a cork, d, near the coiled wire, a ] to a small compass represented by c.” Henry noted that the “inductive action” magnetized the needle “whenever a flash of lightning was perceived, though it might be a distance of several miles.” Moreover, this magnetizing could occur at such great distances that the needle could be “removed, its magnetic condition observed, and another needle put in its place, before the noise of the thunder reached the ear.”

To argue his case further, Henry pointed out that “the effect here described was not produced by the actual transfer of any electricity from the cloud, but was simply the result of induction at a distance.”

From 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).