Professor Henry And His Philosophical Toys


James Smithson, bastard son of the Duke of North-umberland, was a man who kept one eye on posterity. After leaving his fortune to what would one day be called the Smithsonian Institution, he wrote: “My name shall live in the memory of man when the titles of the Xorthumbcrlands and the Percys are extinct and forgotten.”

A debatable prophecy, perhaps. But the name of Smithson has certainly eclipsed that of Joseph Henry, Rrst secretary of the Smithsonian, who set the Institution on a course of research and publication that has made it known and respected the world over, and who, with the possible exception of Benjamin Franklin, can be called the foremost among America’s early scientists.

Today the statue of Toseph Henry which stands 150 feet northwest of the old Smithsonian’s Victorian turrets is little noticed by the throngs of Washington tourists on their way to the Museum of History and Technology. A visiting schoolboy could tell you that Samuel F. B. Morse invented the telegraph, and perhaps even that the Englishman Michael Faraday discovered electrical induction. That is what his textbook would report, at any rate. But the fact is that Henry built the world’s first electromagnetic telegraph, and that he deserves at least equal credit with Faraday for the momentous discovery of induction.

Henry was not always unknown or unappreciated. When he died in May of 1878, his funeral was attended by President Hayes, the Cabinet, and the justices of the Supreme Court. The following January, by joint resolution of Congress, memorial services were held in the House of Representatives. Congressman Samuel S. Cox reminded his colleagues that “No quest for the Holy Grail was ever made with more chivalric, vigilant and reverent pursuit … [His] experiments made the lightning his familiar, his demon, his servitor.” Five years later ten thousand people, including hundreds of Washington dignitaries, attended the unveiling of Henry’s statue. The Marine band played John Philip Sonsa’s “Transit of Venus,” then the Hallelujah Chorus from The Messiah . The throng bowed their heads during the prayer—“that his example may be followed as his serene lame excites the emulation of multitudes of the interpreters of nature.” Xoah Porter, president of Yale University, rose to speak a long eulogy, and ended, in a voice touched with emotion, by quoting Wordsworth’s sonnet on Milton: “Thy soul was like a star …”KewAmericanscientists, before or since, have won such affectionate and reverent acclaim from their contemporaries.

Henry’s work more than deserved such recognition. Why then was his fame so transitory? For one thing, he often tailed to publish the results of his experiments, and in the jealous world of science precedence of discovery is usually accorded to the man who lirst goes on record in a scientific journal. For another, Henry failed to promote or capitalize on his own discoveries. Like Franklin, he never patented any of the inventions that evolved from his research; he believed it incompatible “with the dignity of science to confine benefits which might be derived from it to the exclusive use of any individual.”

More importantly, perhaps, Henry was simply not in step with the age in which he lived and worked. Virtue, he felt, was its own reward. He mistrusted money, associating riches with damnation. He might very well have felt more at home in a socialistic stale than in the booming, competitive economy of nineteenth-century America. Although his name will always survive in lower case as the henry, a unit of electrical inductance, more aggressive men like Fulton, Morse, and Edison, whose dreams of fame and tori une had so much in common with the spirit of the times, made their imprint more strongly. And indeed, Americans have always honored inventors before scientists.

Henry remained aloof from the main stream of capitalism and self-interest all his life. He consistently refused an increase in salary during his thirty-two years at the Smithsonian, and he once turned down an excellent job because, had he accepted, it might have been supposed that he was influenced by pecuniary reasons. Many have blamed this lack of ambition on a rigid Calvinistic upbringing. Henry’s parents and grandparents, of Scottish Puritan stock (the name was Hendrie before it was Americani/ed), arrived in New York on June 16, 1775, the day before the Battle of !Junker Hill. They then moved to Albany, where a number of other Scots had settled. Joseph Henry was probably—no certain record survives—born in 1797.

The boy apparently had no special aptitude lor school, but at an early age he did discover the joys of leading, a favorite book being The Fool of Quality , by Henry Brooke. This moralistic romance, which had gained the approval of John Wesley himself, doubtless helped to confirm his austere Calvinistic: outlook on life. At the age of fourteen he was apprenticed to a watchmaker and silversmith, a training which had proved useful to many ingenious Americans before him, among them David Rittenhouse, Paid Revere, and John Fitch. But unlike these inventors and entrepreneurs, Henry showed little aptitude, and no interest, in the profession of Yankee linkerer. In fact, at a time when most boys of his own age were fascinated by mechanics, Henry decided to become an actor.

He did well enough. At sixteen he was elected president of the Rostrum, an amateur theatrical group for which he wrote, produced, and acted. In the very same year, however, he renounced this second career. He had become intrigued by a book, Gregory’s Lectures on Experimental Philosopliy, Astronomy and Chemistry . It was this, he later recalled, that “fixed my attention upon the study of nature.”

Gregory, an English clergyman, used the question technique to arouse his readers’ interest: “You throw a stone or shoot an arrow into the air; why does it not go forward in a line with the direction you give it? Why does it stop at a certain distance and then return … Again you look into a clear well of water and see your face and figure, as if palmed there. Why is this?” The book in which he found these riddles, largely solved by Isaac Newton a century before, was, as Henry later put it, “by no means a profound work.” But it introduced him to an exciting world in which both his imagination and his reason could play a part.

Plagued by a sketchy education, Henry enrolled in night classes at the Albany Academy, a school so highly ranked at the time that Dr. Eliphalet Nott, president of Union College, called it “a college in disguise.” To pay for his courses Henry first taught grammar in a local school district, then became tutor to General Stephen van Rensselaer’s family. In the years following he diligently studied botany, medicine, chemistry, mathematics, and geology. In 1824 he read his first scientific paper before the Albany Institute, an informal scientific society of some 250 members, on “The Chemical and Mechanical Effects of Steam.” It was an apt subject for an audience that lived on a river bustling with steamboats.

On the side young Joseph Henry tutored Henry James, the future father of William, the psychologist, and Henry, the novelist. To recover his health, strained by the double effort of teaching and studying, he spent a year as a surveyor laying out a road between West Point and Lake Erie. Then, in 1826, he was offered the chair of mathematics and natural philosophy at the Albany Academy.

In the next seven years Henry performed nearly all the experiments for which he was to be remembered. It was the only period in his life when he was sufficiently tree to devote himself to original research. Yet compared with Faraday, who was working on the same problems with the splendid equipment of the Royal Society in London, Henry had little time and inadequate facilities. Most of his work was done at night or during the summer recess when his teaching duties were over and the “laboratory”—a vacant classroomwas at his disposal.

In his first experiments Henry decided to probe the nature of magnetism and electricity, an original choice for several reasons Alter Franklin, electricity had become more of a laboratory diversion than a matter for serious study. In America, knowledge of the subject had almost stood still for a quarter of a century. Moreover, as Henry noted at the time, there was an economic reason for its unpopularity. The primitive batteries of the day and the zinc, acids, and copper wire that went into the necessary apparatus were scarce and expensive. Nevertheless, Henry marked it as a “most fruitful field of discovery”; and perhaps he selected electricity for research simply because, as he said, it was “less generally understood in this country than almost an) other department of natural science.”

At the time liule was known about the connection between electricity and magnetism or if, indeed, any connection existed. So little was known, in fact, that electricity was being generated long before an explanation for its behavior had even begun to evolve.

In 1786 the Italian anatomist Luigi Galvani constructed a primitive electric cell from two different metals and the natural fluids in a dissected frog. But Galvani supposed, in a deduction that was not unreasonable at the time, that the electrical current was coming from the animal itself. Ten years later the physicist Alessandro VoIla eliminated the frog and built a “voltaic pile,” or battery, out of zinc and copper discs placed alternately on top of one another and interleaved with discs of moistened paper. With this continuous source of current at their disposal scientists were able to do away with the old Leyden jar, the electrostatic machine used by Franklin and his colleagues, which produced only a momentary spark.

In 1802 another Italian, Gian Domenico Romagnosi, noticed thai a current (lowing through a wire caused a magnetic needle to line up perpendicularly to the wire. The scientific world ignored the implications of this discovery until 1822, when Hans Oersted, of the University of Copenhagen, rediscovered the effect. Shortly afterward the Englishman William Sturgeon put this relationship between electricity and magnetism to work in an electromagnet. Varnishing an iron bar (for insulation), he wrapped it with copper wire and connected the wire to the terminals of a voltaic battery. This crude device lifted a few pounds of iron.

Oersted and Sturgeon had graphically shown that electricity could produce magnetism. The question was whether the reverse effect—electricity from magnetism—could be obtained. Faraday, fully familiar with the European experiments, thought that it could. In 1822 he wrote confidently in his notebook: “Convert magnetism into electricity.”

Five years later Henry, working part time and with inferior facilities, began to overtake his rival. To increase the power of his electromagnets Sturgeon had increased the size and power of his batteries. Henry had a more sophisticated goal: “The greatest magnetic force with the smallest quantity of galvanism.” He accomplished this by insulating the wire rather than the iron bar. At first he did this, or so the story goes, with white silk ribbons from his wife’s petticoats. By insulating the wire itself he was able to wind many turns around a horseshoe-shaped iron bar. (Sturgeon’s had carried but a single layer, as did the more powerful magnets of Gerard Moll of Holland.) Henry’s 1827 magnet with a single layer lifted fourteen pounds. With a second layer of insulated wire overlapping the lirst, it was able to lift twenty-eight pounds.

In much the same manner Henry built more powerful magnets, using larger iron bars and more turns of copper wire, ingeniously wound to create the greatest force. Sturgeon himself wrote that “Professor Henry has been able to produce a magnetic force which completely efli])ses every other in the whole annals of magnetism.” The Englishman’s crude device had become, in Henry’s hands, one of the wonders of the world- though the world might not have known about Henry’s work had not a publication of Moll’s spurred Henry into writing up his results for Benjamin Silliman’s American Journal of Science and Arts at Yale.

Henry built a magnet for Silliman that would lift 2,300 pounds. (Silliman noted proudly that this was eight times the lifting power of any European magnet.) He also constructed electromagnets for the Penfield Iron Works near Crown Point (later Port Henry), New York, where they were used to extract iron from pulverized ore. Here they caught the eye of an itinerant blacksmith, Thomas Davenport, who later used them in his invention of the rotary motor.

It was Henry, however, who assembled what was probably the world’s first electromagnetic motor, using, as Henry put it in Silliman’s Journal of July, 1831, “a power which I believe has never before been applied in mechanics … magnetic attraction and repulsion.” The design of Henry’s simple device was reminiscent of the “rocker” steam engines of Thomas Newcomen and James Watt. The motor worked very well, but Henry compared the efficiency of the galvanic battery, its power source, with that of coal and noted that it came in a poor second best. “In its present state,” Henry wrote, “[the motor] can only be considered a philosophical toy.” But he had the foresight to add: “… it is not impossible that the same principle … may hereafter be applied to some useful purpose.”

In the meantime Henry had been working on a device from which he expected more immediate and practical results, the electromagnetic telegraph. The telegraph itself was nothing new at the time. Lesage had built one as early as 1774 in Geneva, and in 1798 the Spaniard Francisco Salva communicated over the twenty-six-mile span between Madrid and Aranjuez. But these instruments were not electromagnetic, and they did not have an audible signal. They were powered by the old electrostatic machines originally devised by Otto von Guericke and later used by Franklin and his contemporaries. A charge of static electricity would be built up on the machines, spark up the line, and be observed at the receiving end by the action of pith balls or the leaves of an electroscope-laboratory devices known to everyone who has taken high-school physics.

This was what we now call high voltage, low am. perage current (at the time the volt and the ampere had yet to be defined), and it passed through long wires without any significant diminution. The original voltaic batteries, however, produced high amperage and low voltage. André Ampère was one of the first to suggest that a current passing through a line might serve to transmit a signal, since an observer on the receiving end could note the deflection of a magnetic needle; but he offered no solution as to how this might be done using the ordinary battery as a power source. The problem was pursued further by Peter Barlow, an English mathematics teacher, in 1825, but Barlow found a significant decrease in the strength of his electromagnetic current at a distance of only two hundred feet from his battery. He gloomily concluded that the scheme was totally impractical.

Henry began his work on the telegraph in 1830. Aided by an assistant, he strung 1,060 feet of wire around the lecture room of the Albany Academy and installed an electromagnet at one end, a battery at the other. After several experiments he succeeded in lifting an eight-ounce weight with the electromagnet. Henry observed: “The fact that a magnetic action of a current from a trough is, at least , not sensibly diminished by passing through a long wire, is directly applicable to Mr. Barlow’s project of forming an electromagnetic telegraph …”

Henry’s “trough,” and the way it was connected to the circuit, accounted for the success of this experiment. The trough consisted of a large number of zinc and copper plates in a dilute acid solution. This “intensity” battery produced high voltage or, as Henry put it, would give current enough “projectile force” to send it through a long wire. In addition Henry realized that the battery and the circuit could be arranged in different ways to produce different effects. Thus while the intensity circuit (which we now call a “series” circuit) was necessary to allow a signal to pass through a long wire, Henry used the “quantity” (or “parallel”) circuit to achieve the greatest lifting capacity in his electromagnets. In effect he had anticipated Ohm’s law by matching the resistance of the battery to that of the circuit.

The discovery that electricity could be sent through a long wire was perhaps the most important finding leading to long-distance telegraphy. As Francis O. J. (“Fog”) Smith, one of Morse’s original partners, put it: “Barlow used the quantity battery and Morse used the quantity battery and neither could succeed.” In 1848, in the case Morse v. O’Reilly (O’Reilly was another “inventor” of the telegraph), Morse admitted that Henry had shown that electricity could be transmitted over long distances, but said that he had always “assumed this truth.” This assumption, however, got him at the time no further than Barlow, who had reached the opposite conclusion.

In any event, Henry wasted no time in putting his discovery to dramatic use. In September of 1831 he strung more than a mile of wire around a third-story classroom. At one end he connected the wire to an intensity battery; at the other end the wire was wrapped around an iron bar to form an electromagnet. Close by, set on a pivot, was a permanent magnet. When a surge of current passed through the line activating the electromagnet, it repulsed one end of the permanent magnet. It swung away and clanged a bell.

This was the world’s first electromagnetic telegraph. Moreover, it had an audible signal—later European electromagnetic telegraphs used the old needle-deflection method of signalling. Admittedly it was more of a laboratory toy than a working system, but it was nevertheless in operation a dozen years before Morse demonstrated his Washington-Baltimore line in 1844. Henry made no attempt to patent it as an “invention.” Many years later, however, in one of those rare moments when he indicated that the American dream of fame and fortune had not left him totally untouched, he noted: “In this, I was perhaps too fastidious.”

Thus in a few years of part-time research Henry had invented the modern electromagnet, built the first electric motor, and assembled the first electromagnetic telegraph. He does not usually receive credit for the last two, nor does he for his next and greatest discovery, that of electromagnetic induction, which is generally attributed to Faraday.

Between 1823 and 1831 Faraday several times carried out experiments designed to produce electricity from magnetism. All failed—largely because of the faulty arrangement of his laboratory apparatus. (Faraday was more liable to distrust his own intuition than to doubt the efficiency of the Royal Society’s laboratory equipment.) But finally, in August of 1831, he succeeded.

The experiment was simple enough. Faraday wound two separate coils of wire on an iron ring. One was connected to a battery, the other to a galvanometer, a device for measuring current. Faraday noticed that when—and only when—the battery was being connected or disconnected with the coil, there was a surge of current in the other coil. He had finally found the secret, that a change in a magnetic field produces a current. He subsequently showed, in an even simpler experiment, that a current can be produced simply by thrusting a magnet in and out of a coil of wire. “Distinct conversion of magnetism into electricity,” Faraday wrote triumphantly in his diary. On November 24 he read a paper before the Royal Society, “On the Evolution of Electricity from Magnetism.” And then, after building a working model of an electric generator, the English scientist dropped the search for any practical uses to which this knowledge could be put. “I have rather,” he wrote, “been desirous of discovering new facts … on magneto-electric induction, than of exalting the force of those already obtained.” This scientific credo, an echo of Henry’s approach to applied science, postponed the full development of the dynamo until the i88o’s. Like Henry, however, Faraday was not unaware of the implications of his discovery. When Mr. Gladstone, the Prime Minister, once asked him whether his research had any practical value Faraday replied, “Why sir, you will soon be able to tax it.”

Henry did not hear of Faraday’s achievement until the following April. He made the best of things, dashing off an article for the American Journal of Science and Arts full of excuses for his delay. “I was … accidentally interrupted,” he wrote. “Before having any knowledge of the method given in the above account [Faraday’s], I had succeeded in producing electrical effects in the following manner …”

The experiment Henry cited in his paper was considerably more sophisticated than any Faraday had announced. The result was the same: electricity from magnetism, or “mutual” induction, as it was called. Moreover, toward the end of his paper Henry modestly recorded one brand-new discovery: “I may however, mention one fact which I have not seen noticed in any work.” That “fact” was self-induction, or “extra” current, as it was referred to. Self-induction, first observed as a spark upon the breaking of a long circuit, was the key to multiplex telegraphy and many other systems of the coming electrical age. This tag-end mention of self-induction was a fortunate afterthought on Henry’s part. In 1834 Faraday announced that he had discovered self-induction, assuming it to be an original finding.

Nobody knows the exact date of Henry’s crucial experiment on mutual induction. Mary Henry, his daughter and biographer, claims it may have been in 1829, but other biographers believe August of 1830 to be a more likely date. Many consider the argument academic in view of the fact that Faraday was first by prior publication. Nevertheless, Henry’s paper put Albany on the scientific map with London, and Faraday himself acknowledged the new American learning several years later in London. When Henry, who was travelling abroad, showed him the best way to rig an experiment in self-induction, Faraday is said to have cried out, “Hurrah for the Yankee experiment.”

In 1832, after six years at the Albany Academy, Henry accepted the chair of natural philosophy at Princeton, then the College of New Jersey. There Henry was involved in investigations of natural phenomena so far ahead of his time, and he was making such consistent progress, that it is tempting to speculate on what scientific wonders he might have discovered had his researches not been interrupted.

All the same, what he did discover was impressive enough. Several of his experiments indicated that electromagnetic waves and light waves were similar—a finding of enormous significance to science which was not finally proved until 1900. (Guglielmo Marconi later paid tribute to this work. After successfully transmitting a radio signal across the Atlantic in 1902, he acknowledged his debt to Clerk Maxwell, Lord Kelvin, Heinrich Hertz—and Joseph Henry.) In his study of the sun as a source of energy Henry came very close to another great discovery. “If he had published,” wrote Asa Gray, the great American botanist, “Henry’s name would have been prominent among the pioneers … of the modern doctrine of the conservation of energy.”

At Princeton, Henry built a second telegraph line from his house, behind Nassau Hall, to Philosophical Hall. He showed that a “quantity” current could induce an “intensity” current, that is, that voltage could be stepped up and down. This was the theoretical basis for the modern transformer. Still another invention was that of the electromagnetic relay, a crucial development for the telegraph, with which a weak line signal could be boosted along through a circuit. He also developed the basic form of the telegraph receiver. This was not a galvanometer or a magnetized needle, which European telegraphs were employing, but a magnet operating a movable armature which made rapid signalling and audible reception possible. With this work he completed the development of the four component parts of the telegraph: the electromagnet, the series circuit, the relay, and the receiver.

Henry first operated his relay in 1835. In 1839 Samuel Morse asked Henry if he might visit him at Princeton. The deceptively simple device which Morse had conjured up on board the packet ship Sully , in 1832, was still largely undeveloped. “I should come as a learner,” Morse wrote, “I have many questions to ask.” Morse asked, and Henry, in this and other meetings, told everything he knew about the telegraph and the relay which made long-distance transmission possible. In 1843 Henry made his final contribution to Morse’s telegraph system, assuring Morse that his line wire could be insulated by stringing it above ground on glass bureau-knobs. Only then was Morse finally able to send his historic message from the Capitol in Washington to Alfred Vail in Baltimore: “What hath God wrought?” To put the credit where it was fairly due, many think, Morse might instead have asked: “What hath Henry wrought?”

At this promising point in Henry’s career James Smithson changed the whole course of American science by leaving his money to the United States “to found at Washington, under the name of the Smithsonian Institution, an establishment for the increase and diffusion of knowledge among men.” Congress then proceeded to debate the function of the projected Institution for almost a decade. For the question arose, what was the Smithsonian to be? Although Smithson himself had obviously contemplated a scientific institution, all sorts of schemes were proposed: art center, library, museum, even a mint.

As the foremost scientist in the nation, Henry was immediately consulted by the Board of Regents appointed by Congress. He proposed that to “increase” knowledge the institution should engage in research in various branches of learning; to “diffuse” knowledge it should publish periodicals and reports so that the results of its research could be made known to all men.

Henry’s plan for the Smithsonian was accepted by the Board. Then, after canvassing some of the world’s greatest scientists, including Faraday and François Arago (who had been a friend of Smithson’s), the Regents invited Henry to assume the secretaryship.








Yet Morse, plagued by law suits and perhaps embittered by the scientific community’s recognition of Henry as the first builder of an electromagnetic telegraph as well as the discoverer of the scientific principles behind it, turned on Henry. He is supposed to have told his assistant, Alfred Vail (whom many credit with working out the details of Morse code), that Henry’s claims to discoveries of importance to the telegraph were “jackdaw dreams.” And in 1855 Morse wrote a vitriolic attack on Henry which he euphemistically entitled a “Defence Against the Injurious Deductions Drawn from the Deposition of Professor Henry.” (Henry’s deposition had dispassionately and objectively appraised the contributions to the telegraph made by European inventors.) “I shall show,” Morse said, “that I am not indebted to him [Henry] for any discovery in science bearing upon the telegraph.” The facts clearly contradict Morse’s contention, and one authority on the history of the telegraph has suggested that Morse was, for a time at least, mentally unbalanced.

Henry’s response was characteristic. Rather than answer the attack himself he asked the Board of Regents of the Smithsonian to look into the matter. The Regents’ report, issued in 1857, called the “Defence” a “disingenuous piece of sophisticated argument, such as an unscrupulous advocate might employ to pervert the truth …” That ended the controversy so far as Henry was concerned, though a bitterness lingered for years, and he refused to attend memorial services held after Morse’s death in 1872.

Henry’s later years were quiet. As with most scientists, his great intuitions and insights ended as he aged, though his capacity for work and organization remained undiminished. He played an important part in organizing the National Academy of Sciences and the American Association for the Advancement of Science. During the Civil War, despite the fact that Jefferson Davis had been a close personal friend, Henry became a scientific adviser and confidant of Lincoln’s. Tragically for his biographers, most of Henry’s correspondence and papers were incinerated in a fire that destroyed part of the Smithsonian in 1865. Henry, at first despondent, later thought that this adversity might work to his “spiritual advantage.”

In April of 1878, in his last address before the National Academy of Sciences, Henry wished his colleagues “a rich harvest of scientific results in the ensuing year.” Less than a month later he was dead from Bright’s disease, then incurable. He was eighty years old. The news of the death of the dean of American science was spread over the world by telegraph.

The significance of Henry’s work has been obscured, but it is undeniable. Most of today’s electrical world depends, in one way or another, on his discoveries. He was, as Samuel Cox indicated in his memorial address before Congress, the man behind a technological revolution then taking place and still continuing: “Morse was but the inventor of a machine, Henry the philosophic discoverer of the principle! … Blot out Morse and his machine, and Professor Henry’s instrument, the telegraph, would go on.”

Smithson and the Smithsonian