Tesla: The Life and Times of an Electric Messiah

by Nigel Cawthorne

  After Martin’s article was published in February 1890, a meeting of the AIEE was devoted to Tesla’s AC system. Experiments in the long-distance transmission of AC current were then being conducted in Germany and Switzerland. Westinghouse was opening a hydroelectric plant at a mining camp in Telluride, Colorado, using Tesla’s AC system and the International Niagara Commission announced that it was looking at the best way to exploit the Niagara Falls.

  Whirling through Endless Space

  Tesla agreed to present his work on high-frequency phenomena to the AIEE. The meeting would be open to the public and the journalist covering the symposium for Electrical World also managed to sell a piece to the prestigious mainstream magazine Harper’s Weekly. It said that Tesla had gone beyond noted European physicists such as Professor Heinrich Hertz in his understanding of the electromagnetic theory of light.

  He also put on a number of spectacular demonstrations. In one, light streamed from a wire attached at one end to a coil. In another, a fine thread of platinum wire inside a glass bulb span, forming a funnel of light. He produced light bulbs that worked with just one wire attached, or with none at all, and generated huge sparks and electric flames. Electricity, he showed, would run to earth.

  As a finale, Tesla ran tens of thousands of volts of AC through his body to light up light bulbs and shoot sparks from his fingertips to show that alternating current was not a killer when handled properly. Electrical World said: ‘Exhausted tubes … held in the hand of Mr Tesla … appeared like a luminous sword in the hand of an archangel representing justice.’ Tesla concluded his lecture, saying:

  We are whirling through endless space with an inconceivable speed. All around us everything is spinning, everything is moving, everywhere is energy. There must be some way of availing ourselves of this energy more directly. Then, with the light obtained from the medium, with the power derived from it, with every form of energy obtained without effort, from the store forever inexhaustible, humanity will advance with giant strides. The mere contemplation of these magnificent possibilities expands our minds, strengthens our hopes and fills our hearts with supreme delight.

  In the audience was Robert Millikan (1868 – 1953), who won the Nobel Prize in 1923 for his work on cosmic rays. He said: ‘I have done no small fraction of my research work with principles I learned that night.’

  The London Lectures

  Tesla then took his show to London in 1892, where he gave two lectures at the Royal Institution. There, Tesla said, James Dewar (1842 – 1923), the Institution’s Professor of Chemistry, ‘pushed me into a chair and poured out half a glass of a wonderful brown fluid which sparkled in all sorts of iridescent colours and tasted like nectar. “Now,” he said, “you are sitting in Faraday’s chair and you are enjoying the whisky he used to drink.”’

  It was not lost on Tesla that he was lecturing on the same stage where Faraday had outlined the fundamental principles of electromagnetic induction in the 1830s. Again he put on a show of sparks, glowing wires, no-wire motors and coloured lights that spelt out the name William Thomson, the leading engineer, mathematician and physicist who was in the audience, and who that year, had become Lord Kelvin. Again he ran high-volt AC current through his body, to the amazement of his audience of distinguished scientists.

  He also melted and vaporized tinfoil in a coil and produced a new type of lamp that would disintegrate zirconia and diamonds, the hardest known substances. Then he described the ruby laser which would not be built until 1960. Most of these demonstrations were brand new, not repeats of ones he had given in America.

  He also demonstrated the first vacuum tube. This would later be used to amplify weak radio signals. And he concluded the lecture with speculation that improvements could be made to the transatlantic telegraph cables so that they could carry telephone calls, and the possibility of wireless transmission. The Electrical Review said:

  The lecture given by Mr Tesla … will long live in the imagination of every person … that heard him, opening as it did, to many of them, for the first time, apparently limitless possibilities in the applications and control of electricity. Seldom has there been such a gathering of all the foremost electrical authorities of the day, on the tiptoe of expectation.

  At the end, he tantalizingly informed his listeners that he had showed them ‘but one-third of what he was prepared to do’. Consequently, the audience remained in their seats and he had to deliver a supplementary lecture. He then presented Lord Kelvin with one of his early experimental Tesla Coils which would be crucial in the development of wireless transmission.

  Tesla went on to wow French academicians with a lecture in Paris, before heading home to Gospic where he found his mother gravely ill. She died soon after. He later wrote: ‘The mother’s loss grips one’s head more powerfully than any other sad experience in life.’

  PART TWO: UNLIMITED POWERS

  Chapter 5 – Father of the Wireless

  A mass in movement resists change of direction. So does the world oppose a new idea. It takes time to make up the minds to its value and importance. Ignorance, prejudice and inertia of the old retard its early progress. It is discredited by insincere exponents and selfish exploiters. It is attacked and condemned by its enemies. Eventually, though, all barriers are thrown down, and it spreads like fire. This will also prove true of the wireless art.

  Nikola Tesla

  While in Europe, Tesla visited the Ganz works in Budapest to see a 1000-volt alternator they were building. He also visited Belgrade where the Serbian King Alexander I conferred the special title of Grand Officer of the Order of St Sava on him and the Serbian poet Jovan Jovanovic Zmaj wrote a poem in tribute to him.

  On the return leg of his journey he went to Berlin to visit Hermann von Helmholtz, who developed the mathematics of electrodynamics, then went on to Bonn to see Heinrich Hertz, who was the first man to transmit and receive radio waves. Hertz had conducted his experiments with a simple sparking apparatus that could transmit radio waves across his lab. However, Hertz was a theoretical physicist who simply wanted to investigate the theories of James Clerk Maxwell, not an electrical engineer who wanted to put them to a practical use. Tesla had already duplicated Hertz’s experiments and, from them, developed the Tesla Coil which was capable of transmitting wirelessly over long distances.

  Hertz had sought to demonstrate that space was filled with a substance called ether, which was both inconceivably tenuous, yet extremely rigid. The reasoning was that, if light and other electromagnetic phenomena are waves, they must have something to propagate through. Tesla maintained that such a substance could not exist and the two men did not get on. In fact, the existence of Hertz’s ether had already been disproved experimentally by A.A. Michelson (1852 – 1931) in Germany in 1881 and, again, in collaboration with Edward Morley (1838 – 1923) in the US in 1887.

  On board ship on the way back to the US, Tesla had one of his epiphanies. He was thinking about an experience he had while walking in the Alps. Observing an oncoming thunderstorm, he noticed that rain held off until the first flashes of lightning and wondered whether he could use electricity to control the weather.

  When Tesla arrived back in New York after his triumphal trip, he was greeted with a photograph of Edison signed: ‘To Tesla from Edison.’ Then Westinghouse dropped by with the news that they had won the contract to provide the power for the forthcoming 1893 World’s Fair in Chicago.

  The Wireless Transmission of Power

  Hertz had conducted his experiments with a battery and a simple circuit interrupter, like a Morse key, connected to an induction coil – a small transformer – to produce a high-voltage spark. This could be detected using a copper loop with a spark gap.

  Tesla quickly realized that, instead of a battery with a circuit interrupter, it would be better to use an AC current. While a circuit interrupter would only give a frequency of, at best, a few hundred cycles per second, an alternator could give 10,000 or 20,000 cycles per second. However, once an alternator
reached that speed it began to fly apart, but higher frequencies could be generated electrically.

  He had already used induction coils and capacitors – electrical storage devices such as a Leyden jar – to give split-phase AC currents to run his motors. These could also be used to increase the frequency even higher. Putting a connecting capacitor across the terminals of a coil produced a circuit that resonated, giving a spike in output. He called this the oscillating transformer, though other experimenters began calling it the Tesla Coil. A coil coupled to a capacitor that resonates at a specific frequency is the basis of all wireless transmission.

  Refining his oscillating transformers, he earthed one terminal to the city’s water main, he moved around New York detecting the electromagnetic waves generated at various frequencies. Abandoning Hertz’s primitive spark gaps, he used other tuned circuits and vacuum tubes as detectors. However Tesla’s aim was not to transmit an intelligible signal as we use radio waves now. His goal was the wireless transmission of power.

  The Skin Effect

  Early in these experiments, Tesla accidentally touched a high-voltage terminal and, to his surprise, was unhurt. At high frequencies, electricity exhibits what is known as the ‘skin effect’. The magnetic field created pushes the current to the outside of a conductor, so it does not run through the body, damaging the nerves and muscles. Instead it travels across the surface, leaving the internal structure undamaged. In his public demonstrations, he touched one terminal of a high-frequency apparatus generating tens of thousands of volts and illuminated a bulb or tube held in the other hand. This also showed that alternating current, if at a sufficiently high frequency, was safer than direct current.

  On the Road

  Tesla and his lectures hit the road in 1893, and pulled in huge audiences with his dazzling demonstrations and novel ideas. In Philadelphia, he outlined a method of transmitting pictures – that is, television. The secret of wireless transmission, he said, was resonance. Wires become unnecessary as electrical impulses jump from a sending device to a receiver if they are tuned to the same frequency, and he presented a diagram showing aerials, transmitters, receivers and earth connections, all the elements of a modern broadcast system.

  This was not just theory. He gave practical demonstrations. On one side of the stage he had a high-voltage transformer connected to a bank of Leyden jars, a sparking gap, a coil and a length of wire hanging from the ceiling. On the other side was an identical length of wire and an identical coil and bank of Leyden jars. But instead of the sparking gap there was a Geissler, or discharge tube that glowed when electricity was passed through it, like a primitive neon light.

  Not only was the demonstration dazzling, it was full of strange sounds. When electricity was fed to the transformer, the core strained, making odd groaning sounds. Corona sizzled around the edges of the foil on the Leyden jars and sparks cracked across the sparking gap. But the radio waves travelled noisily from one antenna to the other and the Geissler tube lit up.

  Tesla was advised to play down the possibilities of his wireless system. It seemed so fanciful it might deter conservative businessmen who might otherwise be interested in his motors or his lighting systems. Nevertheless, he said, it earned him the title of ‘Father of the Wireless’ among fellow researchers. Others had investigated the phenomenon of wireless transmission before him, but Tesla had pioneered the use of the tuned circuit, the aerial and the ground connection. He was giving these demonstrations of wireless transmission a full year before Guglielmo Marconi even began experimenting.

  In 1896, Tesla received a letter from Sir William Preece (1834 – 1913) of the Imperial Post Office in London, asking Tesla for two wireless sets for trial. But Marconi was in London by then. He intervened, telling Preece that he had tried the Tesla system and it had not worked. Nevertheless, Tesla filed a patent for wireless transmission in September 1897.

  Conspiring with the Devil

  In St Louis, Missouri, 4,000 copies of a small-circulation electrical journal were sold because it carried an article about Tesla. When Tesla came to town, 80 electrical utility wagons paraded down the street. The 4,000-seat Grand Music Entertainment Hall was filled to overcapacity as several thousand more packed in. Tickets were being sold by scalpers for between $3 and $5 ($80 and $130 at today’s prices). Tesla did not disappoint, passing 200,000 volts through his body. He described the experiment in his published lecture:

  I now set the coil to work and approach the free terminal with a metallic object held in my hand, this simply to avoid burns. As I approach the metallic object to a distance of 8 or 10 inches, a torrent of furious sparks breaks forth from the end of the secondary wire, which passes through the rubber column. The sparks cease when the metal in my hand touches the wire. My arm is now traversed by a powerful electric current, vibrating at about the rate of one million times a second. All around me the electrostatic force makes itself 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 on any part of the body, it produces a sensation like the pricking of a needle. Were the potentials sufficiently high and the frequency of the vibration rather low, the skin would probably be ruptured under the tremendous strain, and the blood would rush out with great force in the form of fine spray or jet so thin as to be invisible, just as oil will when placed on the positive terminal of a Holtz machine [electrostatic generator]. The breaking through of the skin though it may seem impossible at first, would perhaps occur, by reason of the tissues under the skin being incomparably better at conducting. This, at least, appears plausible, judging from some observations.

  I can make these streams of light visible to all, by touching with the metallic object one of the terminals as before, and approaching my free hand to the brass sphere, which is connected to the second terminal of the coil. As the hand is approached, the air between it and the sphere, or in the immediate neighbourhood, is more violently agitated, and you see streams of light now break forth from my fingertips and from the whole hand. Were I to approach the hand closer, powerful sparks would jump from the brass sphere to my hand, which might be injurious. The streamers offer no particular inconvenience, except that in the ends of the fingertips a burning sensation is felt …

  The streams of light which you have observed issuing from my hand are due to a potential of about 200,000 volts, alternating in rather irregular intervals, sometimes like a million times a second. A vibration of the same amplitude, but four times as fast, to maintain which over three million volts would be required, would be more than sufficient to envelop my body in a complete sheet of flame. But this flame would not burn me up; quite contrarily, the probability is, that I would not be injured in the least. Yet a hundredth part of that energy, otherwise directed; would be amply sufficient to kill a person…

  Waving various shaped tubes in the powerful electromagnetic field his oscillating transformer had produced, Tesla created beautiful effects like the ‘spokes of a wheel of glowing moonbeams’, the Electrical Engineer said.

  Towards the end of the performance, Tesla held up one of his phosphorescent lamps, the precursory of fluorescent lights, and announced that he would illuminate it by touching the terminal of his oscillating transformer with his other hand. When he did, the lamp lit up.

  ‘There was a stampede in the two upper galleries and they all rushed out,’ said Tesla. ‘They thought it was some part of the devil’s work.’

  An All-American Joke

  Returning to New York, Tesla acquired his US citizenship. To get back at Edison for his jibe years earlier of ‘You are still a Parisian’, Tesla decided, now that he was a fully-fledged American, to find out if Edison could take an all-American joke. He set up an experiment pitting a carbon-filament incandescent light that Edison had invented against an identical bulb t
hat was empty.

  Applying a current at a frequency of around one million cycles per second, the empty bulb glowed brightly – more brightly than Edison’s bulb which was being run on direct current. What’s more, the empty bulb stayed cool to the touch. Edison was far from amused and, once again, Tesla had shot down his former mentor in the popular press.

  An incandescent light bulb is only 5 per cent efficient. The other 95 per cent is lost in the form of heat. This waste, Tesla said, was ‘on a par with the wanton destruction of whole forests for the sake of a few sticks of lumber’.

  Tesla Keeps Inventing

  However, to Tesla, the attention of the press was a distraction. He went to work increasing the power of his oscillators until he reached one million volts. Then he immersed a high-frequency oscillator in a vat of oil. By modulating the frequency he could get the oil to rotate at different rates.

  Tesla then invented a new steam-driven generator that produced as much power as one 40 times its size. Instead of using the piston action of the steam engine to turn a crankshaft and flywheel, which then turn the generator, he put the cylinder inside the coils of the generator so that the metal pistons moving up and down generated electricity.

  Chicago World’s Fair 1893

  Westinghouse had won the contract to light the World’s Columbian Exposition, aka the Chicago World’s Fair, in May 1893 by putting in a bid much lower than that of General Electric, which now owned Edison’s patents. The buildings at the fair were to be illuminated with 200,000 bulbs, so this was an ideal opportunity to demonstrate how Tesla’s AC system could be used to light an entire city.