Roland J. Morin, the chief engineer of Sylvania GTE International, New York, later wrote: “I am sure that [Tesla’s] demonstration of these light sources at the Chicago World’s Fair [1893] stimulated D. McFarlan Moore to develop and announce commercial realization of the fluorescent lamp….”
Gracious in paying tribute to scientists who had paved the way, Tesla expressed his debt to Sir William Crookes, who in the 1870s had built a vacuum tube with a pair of electrodes inside. Alluding to “that same vague world” (later identified as a stream of electrons), he spoke of the effects obtained with alternating currents of high voltage and frequency: “We observe how the energy of an alternating current traversing the wire manifests itself—not so much in the wires as in the surrounding space—in the most surprising manner, taking the forms of heat, light, mechanical energy and, most surprising of all, even chemical affinity.”
His long fingers deftly chose another prop.
“Here is an exhausted bulb suspending from a single wire…. I grasp it, and a platinum button mounted in it is brought to vivid incandescence.
“Here, attached to a leading wire, is another bulb which, as I touch its metallic socket, is filled with magnificent colors of phosphorescent light.
“Here again,” he said, “insulated as I stand on this platform, I bring my body in contact with one of the terminals of the secondary of this induction coil… and you see streams of light break forth from its distant end, which is set in violent vibration….
“Once more, I attach these two plates of wire gauze to the terminals of the coil. [T]he passage of the discharge… assumes the form of luminous streams.”
It was impossible with an induction coil, he said, to pursue any novel investigation without coming upon some interesting or useful fact. He began to describe effects he had achieved in the laboratory—“large pinwheels, which in the dark present a beautiful appearance owing to the abundance of the streams,” and of how he had sought to produce “a queer flame which would be rigid.”
To his listeners it sometimes seemed as if visual excitement were as important to him as useful results; but then, in the next breath he would present them one “useful fact” after another.
For example, he showed them a motor that ran on only one wire, the return circuit occurring wirelessly through space. And, renewing his spell over men who prided themselves on common sense and resistance to flimflammery, he spoke of the possibility of running motors without any wires at all. He spoke of energy in space, free for the taking.
“It is quite possible,” he said, “that such ‘no-wire’ motors, as they might be called, could be operated by conduction through the rarefied air at considerable distances. Alternating currents, especially of high frequencies, pass with astonishing freedom through even slightly rarefied gases. The upper strata of the air are rarefied. To reach a number of miles out into space requires the overcoming of difficulties of a merely mechanical nature. There is no doubt that with the enormous potentials obtainable by the use of high frequencies and oil insulation, luminous discharges might be passed through many miles of rarefied air, and that, by thus directing the energy of many hundreds of thousands of horsepower, motors, or lamps might be operated at considerable distance from stationary sources. But such schemes are mentioned merely as possibilities. We shall have no need to transmit power in this way. We shall have no need to transmit power at all. Ere many generations pass, our machinery will be driven by a power obtainable at any point of the universe. This idea is not novel…. We find it in the delightful myth of Antaeus, who derives power from the earth; we find it among the subtle speculations of one of your splendid mathematicians…. Throughout space there is energy. Is this energy static or kinetic? If static, our hopes are in vain; if kinetic—and this we know it is, for certain—then it is a mere question of time when men will succeed in attaching their machinery to the very wheelwork of nature….”3
The star exhibit of Tesla’s show, however (to be elaborated on in his later lectures in England and France), was a single six-inch almost empty vacuum tube that he called the carbon-button lamp. With this research tool he explored whole new areas of scientific discovery.4
It was a small glass globe with a tiny piece of solid material mounted on the end of a wire serving as a single-wire connection with the high-frequency current source. The central “button” of material electrostatically propelled the surrounding gas molecules toward the glass globe. They then were repelled back toward the button, striking it and heating it to incandescence as the process occurred millions of times each second.
Depending on the strength of the source, extremely high temperatures could be produced that vaporized or melted most substances instantly. Tesla experimented with buttons composed of diamonds, rubies, and zirconia. He finally found that carborundum did not vaporize as rapidly as other hard materials or make deposits inside the globe— hence the name, carbon-button lamp.
The heat energy of the incandescent button was transferred to the molecules of the slight amount of gas in the tube, causing them to become a source of light twenty times brighter for the amount of energy consumed than Edison’s incandescent lamp.
With hundreds of thousands of volts of high-frequency currents surging through his body, he held in his hand this magnificent creation, a working model of the incandescent sun. With it he demonstrated what he believed to be cosmic rays. The sun, he reasoned, is an incandescent body carrying a high electrical charge and emitting showers of tiny particles, each of which is energized by its great velocity. But, not being enclosed in a glass, the sun permits its rays to strike out into space.
Tesla was convinced that all space was filled with these particles, constantly bombarding Earth or other matter, just as in his carbon-button lamp the hardest material was shattered into atomic dust.
One of the manifestations of such bombardment, he said, was the aurora borealis. Although no record exists of his methods, he announced that he had detected such cosmic rays, measured their energy, and found them moving with a velocity of hundreds of millions of volts.5
The more sober physicists and engineers in his audience, hearing such outrageous claims, kept their counsel. But where was the evidence?
Today it is known that thermonuclear reaction on the sun causes the radiation of X rays, ultraviolet, visible, and infrared rays as well as radio waves and solar particles at the rate of 64 million watts (or volt-amperes) per square meter of the sun’s surface.
Cosmic rays, according to modern knowledge, come in many shapes and forms and are the result of the formation and decay of particles as well as the high-energy collision of particles. They come not only from the sun but from the stars and novae or exploding stars.
Solar electrons and protons reaching the vicinity of the Earth and trapped by Earth’s magnetic field form the Van Allen radiation belts. Solar radiation, visible and invisible, determines the surface temperatures of the planets. Auroral displays are caused by solar-emitted particles that collide with the atoms in our upper atmosphere.
Five years after Tesla’s lecture Henri Becquerel, the French physicist, was to discover the mysterious rays emitted by uranium. Marie and Pierre Curie confirmed his work with their study of radium, whose uranium atoms were exploding spontaneously. Tesla had believed, wrongly, that cosmic rays were the simple cause of the radioactivity of radium, thorium, and uranium. But he was entirely correct in predicting that bombardment with “cosmic rays,” i.e., high-energy subatomic particles, could make other substances radioactive, as was finally demonstrated by Irene Curie and her husband Frédéric Joliot in 1934.
Although the scientific world of Tesla’s time did not accept his theory of cosmic rays, two scientists who later achieved fame in this field would acknowledge a debt to his inspiration. Thirty years were to pass before Dr. Robert A. Millikan rediscovered cosmic rays. He believed them to be, like light, vibratory—that is, that they were photons rather than charged particles. This led to one of the scientific dog fights of
the 1940s between Nobel laureate Millikan and Nobel laureate Arthur H. Compton, who believed—and indeed was adjudged to have proved—that cosmic rays consisted of high-velocity particles of matter, just as Tesla had described them.
Both Millikan and Compton expressed their debt to the intuitiveness of their Victorian predecessor. But science was to march on inexorably, proving cosmic rays more varied and complex than any of them had guessed.
The strange little carbon-button lamp with which Tesla dazzled his audience at Columbia College on May 20, 1891, also embodied the concept of the point electron microscope. It produced electrified particles shooting out in straight lines from a tiny active spot on the button, kept at high potential. On the spherical surface of the globe these particles reproduced in phosphorescent images the pattern of the microscopically tiny area from which they were issuing.6
The only limit to the degree of magnification that could be obtained was the size of the glass sphere. The greater the radius, the greater the magnification. Since electrons are smaller than light waves, objects too tiny to be seen by light waves may nevertheless be enlarged by the patterns produced by emitted electrons.
Vladimir R. Zworykin is credited with having developed the electron microscope in 1939. Yet Tesla’s description of the effect achieved with his carbon-button lamp when he used extremely high vacuum stands with hardly a change in wording for a description of the million-magnification point electron microscope.7
Another effect produced by the carbon-button lamp derived from the phenomenon of resonance. In describing the principle of resonance, Tesla often used analogies of a wine glass and a swing. A wine glass that is broken by a violin’s note is shattered because the vibrations of the air that are produced by the violin happen to be of the same frequency as the vibrations of the glass.
A person in a swing may weigh two hundred pounds and a weak boy pushing it may weigh but fifty and may push but a pound. Yet if he times his pushes to coincide with the turn of the swing from him, and keeps adding a pound each time, he will eventually have to stop to avoid hurling the occupant of the swing out into space.
“The principle cannot fail,” Tesla would say. “It is necessary only to keep adding a little force at the right time.”
And that is why Tesla’s carbon-button lamp may be described as an ancestor of the atom-smasher. Using the hard carborundum button in a nearly air-exhausted globe, connecting it to a source of high, rapidly alternating current, he caused the remaining molecules of air to become charged, thus to be repelled at increasingly high velocities from the button to the glass globe, and thence back to the button, shattering the carbon beads in the button into atomic dust which joined the oscillating air molecules to cause even further disintegration.
“If the frequency could be brought high enough,” he said, “the loss due to the imperfect elasticity of the glass would be entirely negligible….”8
In 1939 Ernest Orlando Lawrence of the University of California, Berkeley, won the Nobel Prize for his invention of the cyclotron. According to one account: “In 1929, Ernest Orlando Lawrence… read a paper by a German physicist who had managed, by giving two electrostatic impulses instead of one, to impart to charged potassium atoms in a vacuum tube twice the energy they would normally get from a given voltage. Lawrence wondered: if the impulse could be doubled, could it not be tripled or multiplied any number of times? The problem was to give the particles a series of impulses a little stronger each time, until, like a child being pushed on a swing, the momentum was greatly increased.”9
He made a particle-pushing machine of glass and sealing wax. The disk-shaped vacuum chamber was only four inches wide. Inside were two electrodes, each shaped like half a round cake box and called D plates. Outside the vacuum chamber was a powerful electromagnet. Electrified particles or protons were whirled in a magnetic field in the circular chamber until they attained very high speed and were then fired out of the chamber in a narrow stream of high-speed atomic bullets. Lawrence’s first model was called a cyclotron because it whirled the protons in circles. Soon he built a larger one that fired protons up to energies of 1.2 million electron volts.
Whether Tesla was actually smashing the carbon’s atomic nucleus, as his first biographer thought, has little bearing on the revolutionary nature of his achievement. The inventor himself described the molecules of the residual gas as violently impinging on the carbon button and causing it to rise to an incandescent state, or a near-plastic phase of the solid.
Lawrence may have had no knowledge of Tesla’s molecular-bombardment lamp. Undoubtedly, however, he did know of the attempts to build an atom-smasher that were made by Gregory Breit and his associates at the Carnegie Institution in Washington, D.C., in 1929, for this group used a 5-million-volt Tesla coil to supply the necessary power. Without such apparatus, the machines necessary to crack the atom could never have functioned.
The descriptions of Tesla’s carbon-button or molecular-bombardment lamp are to be found in the permanent records of five learned societies.* Unfortunately in the early 1890s no society was sufficiently learned to imagine a use for this technological ancestor of the Atomic Age.
Frédéric and Irene Joliot-Curie, Henri Becquerel, Robert A. Millikan, Arthur H. Compton, and Lawrence all won Nobel prizes. Victor F. Hess won the Nobel in 1936 for discovering cosmic radiation. Surely it would be an act of simple justice were the scientific community at least to acknowledge Tesla’s pioneer discoveries in each of their fields.
Although many—perhaps most—of his scientific contemporaries failed to understand his lectures fully, Tesla fired the imaginations of a perceptive few. And like some today who discover him for the first time, a kind of temporary madness seized them. “Not only did he teach by accomplishment,” recalled Maj. Edwin H. Armstrong, who later won fame for his contributions to radio, “but he taught by the inspiration of a marvelous imagination that refused to accept the permanence of what appeared to others to be insuperable difficulties: an imagination the goals of which, in a number of instances, are still in the realms of speculation.”10
The English scientist J. A. Fleming wrote Tesla: “I congratulate you most heartily on your grand success…. After that no one can doubt your qualifications as a magician of the first order. Say the Order of the Flaming Sword.”11
To trace Tesla’s productivity in a sequential fashion in this period is almost impossible. He seemed everywhere at once, working in a dozen fields that overlapped and were interrelated—but always with electricity, that mysterious substance, at the heart of his investigations. To him it was a fluid with transcendental powers that condescended to obey certain physical laws, rather that a stream of discrete particles, or wave packets obeying certain particle laws, as in modern theory.
Nevertheless, in the next few years he was to disclose the whole direction of modern electronics, although the electron itself would not be discovered until 1897 by the British physicist Joseph J. Thomson.
Faraday had shown in 1831 that it was possible to convert mechanical energy into electric current. Then, in the year of Tesla’s birth, England’s Lord Kelvin had made a further discovery that would inspire the Serbo-American when he began seeking a new source of high-frequency currents, higher than could be mechanically produced.
It had been believed that when a condenser was discharged, the electricity flowed out of one plate into the other like water. Kelvin showed that the process was complex, that electricity rushed from one plate into the other and back again until all the stored energy was used up, surging at a tremendously high frequency of hundreds of millions of times a second.
On the day in Budapest when the concept of the rotating magnetic field was revealed to Tesla, he had seen in a flash the universe composed of a symphony of alternating currents with the harmonies played on a vast range of octaves. The 60-cycles-per-second AC was but a single note in a lower octave. In one of the higher octaves at a frequency of billions of cycles per second was visible light. To explore this whole r
ange of electrical vibration between his low-frequency alternating current and light waves, he sensed, would bring him closer to an understanding of the cosmic symphony.
The work of James Clerk Maxwell in 1873 had indicated the existence of a vast range of electromagnetic vibrations above and below visible light—vibrations of much shorter and much longer wavelengths. This theory had been tested by Prof. Heinrich Hertz of Germany who, in a search for waves longer than light or heat, first produced man-made electromagnetic radiation at Bonn in 1888. Hertz’s experiments with the spark discharge of an induction coil had proved the existence of a magnetic field when he sent a powerful electric charge across a spark gap, causing a smaller spark to jump across a second gap some distance away. At the same time in England, Sir Oliver Lodge was seeking to measure tiny electrical waves in wire circuits.
Hertz’s equipment had been feeble and the spark coil both impractical and dangerous. Tesla now came up with something both different and very much superior: a series of high-frequency alternators producing frequencies up to 33,000 cycles per second (33,000 Hz.).* This type of machinery was in fact the forerunner of the great high-frequency alternators developed by others for continuous-wave radio communication in the distant future, but for the inventor’s immediate needs, the device was still inadequate. He therefore went on to build what is known as the Tesla coil, an air-core transformer with primary and secondary coils tuned to resonate—a step-up transformer which converts relatively low-voltage high current to high-voltage low current at high frequencies.
This device for producing high voltages, which is today used in one form or another in every radio and television set, was in a very short time to become part of the research equipment of every university science laboratory. It allowed the operator to convert the weak, highly damped oscillations of the original Hertz circuit and to sustain currents of almost any magnitude. In this research Tesla thus anticipated by several years the first experiments of Marconi.
Tesla: Man Out of Time Page 9