Says W. B. Taylor, in an address before the "Philosophical Society of Washington:" "The electro-magnet figured and described by Sturgeon consisted of a small bar or stout iron wire bent into a [Inverted U-Symbol] or horse-shoe form, having a copper wire wound loosely around it in eighteen turns, with the ends of the wire dipping into mercury-cups connected with the respective poles of a battery having one hundred and thirty square inches of active surface."
Henry improved upon this in 1828, but in March of 1829 he exhibited before the Institute a somewhat larger magnet. "A round piece of iron about one-quarter of an inch in diameter was bent into the usual form of a horse-shoe, and, instead of loosely coiling around it a few feet of wire as is usually described, it was tightly wound with thirty-five feet of wire covered with silk, so as to form about four hundred turns; a pair of small galvanic plates, which could be dipped into a tumbler of diluted acid, was soldered to the ends of the wire, and the whole mounted on a stand. With these small plates, the horse-shoe became much more powerfully magnetic than another of the same size and wound in the usual manner, by the application of a battery composed of twenty-eight plates of copper and zinc each eight inches square."
"To Henry, therefore," says Mr. Taylor, "belongs the exclusive credit of having first constructed the magnetic 'spool' or 'bobbin,' that form of coil since universally employed for every application of electro-magnetism, of induction, or of magneto-electrics. This was his first great contribution to the science and to the art of galvanic magnetization....
"But, in addition to this large gift to science, Henry has the preeminent claim to popular gratitude of having first practically worked out the differing functions of two entirely different kinds of electro-magnet; the one surrounded with numerous coils of no great length, designated by him the 'quantity' magnet, the other surrounded with a continuous coil of very great length, designated by him the 'intensity' magnet.... Never should it be forgotten that he who first exalted the 'quantity' magnet of Sturgeon from a power of twenty pounds to a power of twenty hundred pounds was the absolute CREATOR of the 'intensity' magnet; and that the principles involved in this creation constitute the indispensable basis of every form of the electro-magnetic telegraph since invented."
Professor Silliman of Yale College said: "Henry has the honor of having constructed by far the most powerful magnets that have ever been known; and his last, weighing (armature and all) but 82-1/2 pounds, sustains over a ton;--which is eight times more powerful than any magnet hitherto known in Europe."
"In 1831," says Professor Henry, "I arranged around one of the upper rooms of the Albany Academy a wire of more than a mile in length, through which I was enabled to make signals by sounding a bell. The mechanical arrangement for effecting this object was simply a steel bar, permanently magnetized, of about ten inches in length, supported on a pivot, and placed with its north end between the two arms of a horse-shoe magnet. When the latter was excited by the current, the end of the bar thus placed was attracted by one arm of the horse-shoe and repelled by the other, and was thus caused to move in a horizontal plane and its further end to strike a bell suitably adjusted." This was the first "sounding" electro-magnetic telegraph. With this growing fame he was not disposed to think too highly of himself. A friend, noticing a look of sadness in the face of the young professor, said to him,--"Albany will one day be proud of her son;" and so it proved.
A year before this, in May, 1830, Professor Henry had married, at thirty-one, Harriet L. Alexander of Schenectady, N. Y., a cultivated and helpful woman.
In 1832, Princeton College needed a professor of natural philosophy. Henry's friends heartily commended him for the position. Silliman said,--"Henry has no superior among the scientific men of the country," and Professor Renwick of Columbia College, New York, said, "He has no equal."
After six years at the Albany Academy, Henry removed to Princeton, where for fourteen years he added constantly to his fame and usefulness by original work. Of his discoveries in these fruitful years he gives the following summary, at the request of a friend:--
"I arrived in Princeton in November, 1832, and, as soon as I became fully settled in the chair which I occupied, I recommenced my investigations, constructed a still more powerful electro-magnet than I had made before,--one which would sustain over three thousand pounds,--and with it illustrated to my class the manner in which a large amount of power might, by means of a relay magnet, be called into operation at the distance of many miles.... The electro-magnetic telegraph was first invented by me, in Albany, in 1830.... At the time of making my original experiments on electro-magnetism in Albany, I was urged by a friend to take out a patent, both for its application to machinery and to the telegraph; but this I declined, on the ground that I did not then consider it compatible with the dignity of science to confine the benefits which might be derived from it to the exclusive use of any individual. In this perhaps I was too fastidious."
Professor Asa Gray well said, "For the telegraph and for electro-magnetic machines, what was now wanted was not discovery, but invention; not the ascertainment of principles, but the devising of methods." Morse is not to be less honored because somebody discovered the principle, which he and others utilized for the race, any more than Edison, Bell, and others, because Faraday and Henry helped to make their grand work possible.
"My next investigation, after being settled at Princeton," says Professor Henry, "was in relation to electro-dynamic induction. Mr. Faraday had discovered that when a current of galvanic electricity was passed through a wire from a battery, a current in an opposite direction was induced in a wire arranged parallel to this conductor. I discovered that an induction of a similar kind took place in the primary conducting wire itself, so that a current which, in its passage through a short wire conductor, would neither produce sparks nor shocks would, if the wire were sufficiently long, produce both those phenomena....
"A series of investigations was afterwards made, resulting in producing inductive currents of different orders, having different directions, made up of waves alternately in opposite directions....
"Another series of investigations, of a parallel character, was made in regard to ordinary or frictional electricity. In the course of these it was shown that electro-dynamic inductive action of ordinary electricity was of a peculiar character, and that effects could be produced by it at a remarkable distance. For example, if a shock were sent through a wire on the outside of a building, electrical effects could be exhibited in a parallel wire within the building."...
After this, investigations were made in atmospheric induction; induction from thunder clouds; in regard to lightning rods; on substances capable of exhibiting phosphorescence, such as the diamond, which, when exposed to the direct rays of the sun, and then removed to a dark place, emits a pale blue light; on a method of determining the velocity of projectiles; on the heat of the spots on the sun as compared with the rest of his disk; the detection of heat by the thermal telescope--"when the object was a horse in a distant field, the radiant heat from the animal was distinctly perceptible at a distance of at least several hundred yards;" on the cohesion of liquids; on the tenacity of soapwater in films; on the origin of mechanical power, and the nature of vital force.
Henry says:--
"The mechanical power exerted by animals is due to the passage of organized matter in the stomach, from an unstable to a stable equilibrium; or, as it were, from the combustion of the food. It therefore follows that animal power is referable to the same source as that from the combustion of fuel--namely, developed power of the sun's beams. But, according to this view, what is vitality? It is that mysterious principle--not mechanical power--which determines the form and arranges the atoms of organized matter, employing for this purpose the power which is derived from the food....
"Suppose a vegetable organism impregnated with a germ (a potato, for instance) is planted below the surface of the ground, in damp soil, under a temperature sufficient for vegetation. If we examine it from time to time, we find it sending down rootlets into the earth, and stems and leaves upward into the air. After the leaves have been fully expanded we shall find the tuber entirely exhausted, nothing but a skin remaining. The same effect will take place if the potato be placed in a warm cellar; it will continue to grow until all the starch and gluten are exhausted, when it will cease to increase. If, however, we now place it in the light, it will commence to grow again, and increase in size and weight. If we weigh the potato previous to the experiment, and the plant after it has ceased to grow in the dark, we shall find that the weight of the latter is a little more than half of the original tuber. The question then is, what has become of the material which filled the sac of the potato? The answer is, one part has run down into carbonic acid and water, and in this running down has evolved the power to build up the other part into the new plant. After the leaves have been formed and the plant exposed to the light of the sun, the developed power of its rays decomposes the carbonic acid of the atmosphere, and thus furnishes the pabulum and the power necessary to the further development of the organization.
"The same is the case with wheat, and all other grains that are germinated in the earth. Besides the germ of the future plant, there is stored away, around the germ, the starch and gluten to furnish the power necessary to its development, and also the food to build it up, until it reaches the surface of the earth and can draw the sources of its future growth from the power of the sunbeam. In the case of fungi and other plants that grow in the dark, they derive the power and the pabulum from surrounding vegetable matter in process of decay, or in that of evolving power."...
"What then is the office of vitality? We say that it is analogous to that of the engineer who directs the power of the steam-engine in the execution of its work."
"If he had published in 1844, with some fulness, as he then wrought them out," says Professor Gray, "his conception and his attractive illustrations of the sources, transformation, and equivalence of mechanical power, and given them fitting publicity, Henry's name would have been prominent among the pioneers and founders of the modern doctrine of the conservation of energy."
Henry always defined science as the "knowledge of natural law," and law as the "will of God." He found all things, even the storms, under the "control of laws--fixed, immutable, and eternal," and rejoiced in believing that "a Supreme Intelligence who knows no change" governs all. For him there was never any conflict between science and religion.
In February, 1837, Henry went to Europe, accompanied by Prof. Alexander D. Bache, at the head of the United States Coast Survey for eighteen years. He became the friend of Faraday; of Wheatstone, then Professor of Experimental Philosophy in King's College, who was engaged in developing his system of the needle telegraph; of Arago, Gay-Lussac, and other noted men. "At King's College," says Prof. Alfred M. Mayer, "Faraday, Wheatstone, Daniell, and Henry had met to try and evolve the electric spark from the thermopile. Each in turn attempted it and failed. Then came Henry's turn. He succeeded, calling in the aid of his discovery of the effect of a long interpolar wire wrapped around a piece of soft iron. Faraday became as wild as a boy, and, jumping up, shouted: 'Hurrah for the Yankee experiment!'" "It is not generally known or appreciated," says Professor Mayer, "that Henry and Faraday independently discovered the means of producing the electric current and the electric spark from a magnet.... Henry cannot be placed on record as the first discoverer of the magneto-electric current, but it can be claimed that he stands alone as its second independent discoverer." Both James D. Forbes of Edinburgh and Henry obtained the spark, but were anticipated by Faraday.
Henry spoke before the various scientific societies. He was no longer the apprentice to a watch-maker, or the leader of private theatricals, but a distinguished scholar. By his own will and energy he had attained to this enviable position.
Meantime a man of science, in England, had thought out a great project for the benefit of his fellow-men. James Smithson, a wealthy English chemist, a Fellow of the Royal Society, unmarried, died in 1829. He left his property, over five hundred and forty thousand dollars, after the death of his nephew, provided that he died childless, "to the United States of America, to found at Washington, under the name of the Smithsonian Institution, an establishment for the increase and diffusion of knowledge among men." The nephew died six years later, unmarried.
This was indeed a wonderful gift,--and from a stranger! Difficulties at once presented themselves. How could the property be used "for the increase and diffusion of knowledge among men"? "For ten years," says Garfield, "Congress wrestled with those nine words of Smithson, and could not handle them. Some political philosophers of that period held that we had no constitutional authority to accept the gift at all, and proposed to send it back to England. Every conceivable proposition was made."
John Quincy Adams desired a great astronomical observatory. One person wished an agricultural school; another, a college for women; another, that the funds should be devoted to meteorological observations all over the Union. Finally, a board of regents was appointed, with power to choose a suitable person as secretary.
He must be a learned man, a wise financier, with good judgment and pleasant manners. Professor Henry fulfilled all the conditions. He was admired for his learning; in finance he was wise, as thirty years have proved, the institute with its endowment now being valued at one and a half million dollars; his kindly manner made him accessible, willing to listen to any one who hoped or believed he had discovered something in the line of knowledge. A man who can be harsh or cold to an ignorant person, or indeed to anybody, does not deserve to hold any public position. With natural quickness of temper in early life, he had gained remarkable self-control. Like Baron Cuvier, he had no tolerance for sarcasm or "practical jokes." Henry was unanimously chosen, entering upon his duties December 3, 1846. He had a definite plan of the work which ought to be done, and "after due deliberation it received the almost unanimous approval of the scientific world."
Famous Men of Science · The Wunder Library — complete classics, free to read, with narration.