by Marc Seifer
The question of who invented the radio is complex, for there was no single developer. Experiments in wireless can be traced back to Joseph Henry, who, in 1842, transmitted electrical energy across a thirty-foot room between magnetized needles and sensitive Leyden jars, and to Samuel Morse, who sent messages in 1847 by means of induction across an eighty-foot-wide canal by using something called “current leakage.”35
The first individual to transmit messages over long distances using aerials (in the form of kites) and a ground connection was Mahlon Loomis. A dentist and experimentalist who also used electricity to stimulate growth in plants, Loomis not only received a patent on the device in 1872 but also successfully introduced the “Loomis Aerial Telegraphy Bill” before the U.S. Congress. Loomis made such an impact that $50,000 was appropriated to help him in his pursuit. In 1886, Loomis sent wireless messages fourteen miles between two mountains in Virginia, and a few years later, he also sent messages between ships two miles apart in Chesapeake Bay. There is little doubt that Tesla was aware of Loomis. For one thing, his patent was registered, and Tesla always made it a practice to study the work of his precursors. Also, it should be noted that some of the wording from Loomis’s patent applications and published writings sound eerily like the wording in some of Tesla’s discourses. For instance, Loomis discusses the passing of “electrical vibrations or waves around the world,” and principles of harmonics and resonance, and he also refers to harnessing “the wheelwork of nature,” a favored term of Tesla’s.36
In 1875, Thomas Edison, while working with Charles Batchelor, noticed an unusual sparking effect emanating from the core of an electromagnet which leaped to noncharged bodies several feet away. By using an electroscope, he was unable to distinguish a charge.37 In actuality, he had created a high frequency that could not be detected by his equipment. “By charging a gas main, Edison was able to obtain sparks from the fixtures in his house several blocks away…Edison thought that since energy can take various forms, and it was possible to change electricity to magnetism, magnetism might be transformed into something else.”38 Edison therefore announced to the scientific community that he had discovered a new “unknown force.” Possibly, Tesla’s ideas of connecting an oscillator to the water mains of a city may have been influenced by this research.
In the early 1880s, William Preece, electrical engineer for the British Post Office, began directing experiments in wireless communication by means of an inductive apparatus. He was probably also the first inventor to realize that the earth itself was an integral component in the successful implementation of any wireless system. After isolating the role of the earth as either a primary or secondary circuit, Preece utilized telephone receivers as detecting devices and concluded that “on ordinary working telegraph lines the disturbance reached a distance of 3,000 feet, while effects were detected on parallel lines of a telegraph 10 to 40 miles apart in some sections of the country.” Preece’s work of detecting earth currents, which was duplicated by Western Union engineers in the United States, significantly influenced the theories expounded by Tesla.39
Preece had displayed a long-standing interest in wireless communications. He had visited Edison in the mid-1880s, just after Tesla emigrated to America, to witness firsthand Edison’s latest invention, which he called the “grasshopper telegraph,” a device for jumping messages from dispatch stations to moving trains. By means of induction or resonance, a metal strip attached to a telephone receiver on a moving railroad car would send or receive messages from a similar strip strung parallel to the track at the station. Although the invention never evolved beyond this primitive early stage, the patent would later have important legal significance in priority battles over the invention of the wireless.
Thus, Edison is clearly one of the fathers of wireless transmission, as are Henry, Morse, Loomis, and Preece. Concerning the history of radio tubes, Edison also had an important invention, discussed above, of a dualfilament lightbulb which displayed a flow of current between them, Preece having named it the “Edison effect.” J. J. Thomson used it to help in his discovery of the electron, and Tesla combined information from this device with Crookes’s work on radiation effects inside evacuated glass tubes to invent his “brush phenomena,” which was the first such vacuum tube explicitly created for wireless transmission of intelligence.
Other precursors to Tesla included Heinrich Hertz, Oliver Lodge, and Edouard Branly. A French professor of physics, Branly, perhaps influenced by the knowledge of the Edison effect, noticed that the gap of Hertz’s tuned circuits could be replaced by a glass-enclosed tube which contained finely scattered metallic particles. When current passed through the tube by means of wireless induction, the particles aligned themselves along the path of the gap and closed the circuit. A light tapping on the tube opened the circuit once again until transmission occurred. Lodge perfected Branly’s 1890 discovery of particle cohesion and labeled it the “coherer.”40
These scientists were not thinking about “wireless telegraphy” at the time of their initial work. They were explorers in a new field of electromagnetic induction, and it was not until 1894, by Lodge’s own calculation, that he thought in terms of utilizing the equipment as a means of conveying information.41 On the other hand, we remember that Crookes, writing in 1892, at the very time he was meeting with Tesla in England, noted that he had experimented in the wireless transmission of Morse code from one end of a house to another at about the same time as Hertz and Lodge were experimenting in the late 1880s, but he never publicized his work or furthered the invention beyond this casual experiment.
Tesla realized, as did Hertz, that the Hertzian frequencies through space were not conductive for long-range communication, but unlike Hertz, Tesla sought a way around this limiting factor. Therefore, he devised not only the means of securing more powerful transmitters but also “concatenated tuned circuits,” which were, in essence, sensitive radio tubes for receiving information.42 During this speech in Philadelphia, Tesla also introduced the concept of using both an aerial and ground connection and a single wire as a return for the operation of “all kinds of devices.” This system of wireless transmission was outlined in detail in highly visible articles which appeared in 1891, during his first public demonstrations of wireless Geissler tubes at Columbia College, in 1892 in Europe, and were explicitly delineated in 1893. It would be another full year before a high school boy by the name of Guglielmo Marconi would begin his first tinkerings in the field.
12
ELECTRIC SORCERER (1893)
It was known that Mr. Tesla, who enjoys a high reputation as an electrician, had been experimenting upon a practically new electric light, but it was not known outside his laboratory that he had achieved such wonderful results or come so near [to] revolutionizing the theory of light. Other electrical explorers, especially Dr. Hertz and Dr. Lodge, had evolved the theory that the phenomena of light were related to the electro-magnetic vibrations of ether or air, but it remained for Mr. Tesla to demonstrate this fact and make the knowledge practically available.
NEW YORK RECORDER1
Tesla left Philadelphia by rail at the end of February for the National Electric Light Association convention in St. Louis. Accompanied by T. C. Martin, who was covering both lectures for Electrical Engineer, they discussed the creation of a textbook based on the inventor’s collected writings. The first half would be devoted to the full range of inventions associated with the AC polyphase system, with chapters on motor design, single phase and polyphase circuits, armatures, and transformers; the second half would contain Tesla’s three discourses on high-frequency phenomena, which he had presented in New York, London, and Philadelphia. With an introduction written by Martin and a few miscellaneous articles at the end, the treatise would run almost five hundred pages. Josh Wetzler would be second editor. Publication date was set for the end of the year.
Martin had achieved a great coup, solidifying a deal with what many people were saying was “the greatest living electrician.�
��2 The Inventions, Researches and Writings of Nikola Tesla would be a landmark text, becoming a virtual bible for the numerous electricians who read it.
On February 28, Tesla arrived in St. Louis, invited to speak by James I. Ayer, general manager of the local Municipal Electric Light & Power Company. The arrival of the inventor created a jolt of excitement. His speech was billed as a replication of the London Lecture. “Over four thousand copies of the journal containing [a] biographical sketch were sold upon the streets…something unprecedented in the history of electrical journalism.”3 A procession of eighty electrical utility wagons and metermen carts rolled down Main Street as thousands of people clamored to get tickets for the performance.4
At the opening ceremony, both Tesla and Ayer were inducted into the association as honorary members;5 afterward, Ayer introduced Tesla to one of his engineers, H. P. Broughton, a recent graduate of Cornell University, who was assigned as an assistant for the duration of the convention.6
The chamber allocated proved to be too small, so the event was moved to the Grand Music Entertainment Hall, a large auditorium with a seating capacity of over four thousand. Tickets were hawked on the steps for anywhere from three to five dollars. Yet even this theater proved to be inadequate, for the house was “crowded to suffocation.”7
Mr. Ayer introduced the inventor to the audience “with a sort of reverence as one who has an almost magic power over the vast hidden secrets of nature” and presented Tesla with “a magnificent floral shield, wrought in white carnations and red Beauty roses.”
Peering out at the sea of faces, Tesla realized that it would be wise to restrict his lecture to the more “spectacular” experiments. With Broughton, he displayed his invention of wireless transmission of electrical energy by lighting up wireless receiving tubes by throwing a switch from the opposite side of the room.
“Of all the many marvelous things we observe,” he said, “to me it seems, a vacuum tube excited by an electric impulse from a distant source, bursting forth out of the darkness and illuminating the room with its beautiful light, is as lovely a phenomenon as can greet our eyes.”8
“By way of amusement,” Tesla created sheets of electricity between two condenser plates. He illuminated lightbulbs with and without filaments, ignited phosphorescent globes that “threw a most dazzling light far beyond that yielded by any ordinary phosphorescence,” and created strobe effects by whirling tubes that “look[ed] like white spokes of a wheel of glowing moonbeams.”
Tesla then approached his most powerful coil.
Noticing Prof. George Forbes in the audience, the engineer from Glasgow who had so highly recommended his AC system to the Niagara Power Commission, the inventor bowed in respect. Acknowledging his appreciation, Tesla predicted that ere long great surges of electrical energy based on this work would soon usher from the great waterfall.
These next series of experiments are shown with some reluctance; yet forced thereto by the desire to gratify those who had shown such interest and formed so large an audience, I see I have little choice…Charg[ing] my body with electricity from an apparatus which I have devised, I can make the electricity vibrate at the rate of a million times a second. The molecules of the air are then violently agitated, so violently that they become luminous, and streams of light then come out from the hand. In the same manner I am able to take in the hand a bulb of glass filled with certain substances and make them spring into light.9 I had the pleasure of performing these very experiments privately before Lord Rayleigh, and I will always remember this distinguished scientist trembling in eagerness and excitement when he witnessed them. The appreciation I have received from such a distinguished scientist as he has repaid me fully for the pains to which I have worked to achieve these ends.10
Tesla thereupon turned to the coil and announced that due to the enormous potentials about to be generated, he had constructed the machine with hard rubber insulation, “as even dry wood is by far too poor” for protection.11
I now approach the free terminal with a metallic object held in my hand, this simply to avoid burns. The sparks cease when the metal…touches the wire. My arm is now traversed by a powerful electric current, vibrating at about a million times a second. All around me the electrostatic force is felt, and the air molecules and particles of dust flying about are acted upon and are hammering violently against my body. So great is this agitation of the particles, that when the lights are turned out you may see streams of feeble light appear on some parts of my body. When such a streamer breaks out, it produces a sensation like the pricking of a needle. Were the potentials sufficiently high and the frequency low, the skin would probably be ruptured under the tremendous strain, and the blood would rush out with great force in the form of a fine spray.12
Extending his fingers like a preening peacock, the electric sorcerer issued flames of lightning as if he were Thor himself. “The streamers offer no particular inconvenience,” he assured the audience, “except that in the ends of the finger tips a burning sensation is felt.”
With his coil still charged and flames still shooting from his head, a number of other effects were displayed, including the running of motors by way of energy through his body and the lighting of a variety of colorful tubes which the inventor waved about as if they were phosphorescent rapiers. His finale included the stretching of a series of long cotton strings across the stage which he zapped with a pencil-line corona of violet that etched a dazzling glow along its length, illuminating the stage in an eerie iridescence. Shouts of “Bravo” accompanied the thunderous applause as “the lecturer bowed again and again” in response.
Shimmering from aftereffects and still “emitting ethereal flames and fine halos of splintered light”13 after the lecture, Tesla was called to the lobby so that he could be greeted by many members of the admiring public. “So great was the desire…to see Mr. Tesla closer…[that] several hundreds of the leading citizens seized the opportunity and Mr. Tesla’s hand in a very vigorous manner.”14
Upon his return to New York, Tesla completed his citizenship requirements. No longer would his patent applications refer to him as “a subject of the Emperor of Austria,” but rather as “a citizen of the United States.” This was a proud moment. He would keep these papers safely stored away in a vault in his room for the rest of his life.
Now a full “American,” Tesla decided once and for all to take on the mighty icon Thomas Edison. Setting up one of his most provocative experiments, the upstart attacked head-on Edison’s carbon filament lamp. Taking two identical bulbs, one filled with air and the other containing a vacuum, and attaching to it “a current vibrating about one million times a second,” Tesla demonstrated that the lamp filled with ordinary air did not glow but the one with the vacuum glowed brightly. “This showed the great importance of the rarefied gas in the heating of the conductor”; and furthermore, the new light was cool to the touch. Brazenly, Tesla could conclude: “In incandescent lighting, a high resistance filament [Edison’s invention] does not at all constitute the really essential element of illumination.”15
Taking the same two bulbs, Tesla then lowered the frequency, converted it to DC, and showed that the filament in the nonexhausted bulb now began to glow, though not as intensely as the other. He concluded that with DC the filament was the essential component; with high-frequency AC, the atmosphere around the filament, and thus the vacuum, was paramount. The higher the frequency, the more efficient the illuminant. In fact, he noted, if DC were abandoned altogether and extremely high frequencies used, there would be no need for a filament at all!
Edison became perturbed not only because he had sent men to the Orient, Central America, and the Amazon in order to find the perfect filament but also because one or two of them died in the quest.16 That pompous Serb was not only saying that AC was intrinsic to the development of any practical lighting system; he was also proclaiming that Edison’s most famous work would eventually be for naught.
At a cottage by Edison’s rock-crushin
g factory in Ogden, New Jersey, a local newspaper reporter asked the inventor about the “possibility of producing light from electricity without heat.”17 Edison murmured that this feat had been achieved, but the reporter pressed him. “I specifically mean with reference to discoveries in the line taken up by Nikola Tesla.”
Edison “rose from his easy chair,” spat another wad of tobacco off the porch, and barked, “It is a problem surrounded by difficulties.”
“And what about Tesla?”
“He has made no new discovery,” the chief wizard began, “but has shown considerable ingenuity in increasing vibrations. He gets his results from the induction coil and the Geissler tube.”
“Do you think it will replace your light bulb?”
“Light without heat may be obtained some day, but I do not care to prophesy that it will be a pleasant light. Its biggest trouble is its quality. It is a ghastly color, more like the light of lightning bugs than anything else.”
Certainly, in this regard, Edison was entirely correct, as even today the lightbulb generates a more pleasant glow than fluorescent tubes. However, as anyone who has changed a lightbulb knows, Edison’s invention is constructed so as to break down within a few months, whereas Teslaic fluorescent lights can last for years, even decades. Furthermore, according to Tesla’s view, the incandescent lamp created a harsh, bright light from a small central source. It was Tesla’s plan to create a pleasing light from a very large, spherical surface.
Now, for the first time, Nikola Tesla was sought after by the popular press. Quoted as being “modest” by many interviewers and sometimes selfeffacing, initially Tesla avoided publicity. But his sensational accomplishments had made him a folk hero, and it was now up to the journalists to find out why.