The need for insulating this high-voltage equipment led to his immersing it in oil to exclude all air, a method that soon found valuable commercial application, since it became the universal way of insulating all high-tension apparatus. To reduce resistance in his coils, Tesla used stranded conductors with separately insulated strands. Since he seldom took time to patent his research tools or methods, this too went into the common pool of knowledge. It was later commercialized by others, becoming known as “Litz wire,” a term derived from Litzendraht (“stranded wire”) cable.
He then developed a new kind of reciprocating dynamo adapted to his special needs in high-frequency currents—an ingenious single-cylinder engine without valves, that could be operated by compressed air or steam. The speed it attained was so remarkably constant that he proposed adapting it to his 60-cycle polyphase system, using synchronous motors, properly geared down, as a means of providing the correct time wherever in the world alternating current was available. This was the inspiration for the modern electric clock.12 Tesla, in his rush of discovery, took no time to patent a timekeeper either.
And not least, from the dangerous experiments in which he learned to work with hundreds of thousands of volts of high-frequency electricity came another discovery of great importance to the world. In 1890 he announced the therapeutic deep-heating value of high-frequency currents on the human body. The process became known as diathermy. From it would flow an enormous field of medical technology, with many early imitators both in America and Europe.13
7. RADIO
Long hours of mental exertion in his New York laboratory over many months caused Tesla to experience a strange partial amnesia at the start of the 1890s.
Immediately after finishing his consulting work for the Westing-house corporation, he had become obsessed with what was first spoken of as the wireless telephone—or simply wireless—and later by its modern name, radio.
After building the powerful coils in his laboratory, he had ascertained that broadcasting intelligence was simply one aspect of a vast global and interplanetary potential. Radio posed a different set of problems from transmitting electricity without wires, yet he believed them close enough to be tackled in a single stunning orchestration.
“I had produced a striking phenomenon with my grounded transmitter,” he later recalled, “and was endeavoring to ascertain its true significance in relation to the currents propagated through the earth. It seemed a hopeless undertaking, and for more than a year I worked unremittingly but in vain. This profound study so entirely absorbed me that I became forgetful of everything else, even of my undermined health. At last, as I was on the point of breaking down, nature applied the preservative, inducing lethal sleep.”1
From having gone almost without rest for months, he said that he had then slept “as if drugged.” On regaining his senses, he was shocked to discover that he could visualize no scenes from his past except those of earliest infancy.
Having developed a marked indifference to medical doctors, he put his mind to the problem of curing himself.
Night after night he concentrated on the memories of early childhood, gradually bringing more and more of his life into focus. In this unfolding process the image of his mother was always the principal figure. He began to feel a consuming desire to go to her.
“This feeling grew so strong,” he recalled, “that I resolved to drop all work and satisfy my longing. But I found it too hard to break away from the laboratory and several months elapsed, during which I succeeded in reviving all the impressions of my past life….”
It was early spring of 1892. He had not yet accepted a flock of invitations to lecture in England and France and indeed was still in a state of emotional conflict about doing so.
Then, he recalls, a vision materialized “out of the mist of oblivion,” and he saw himself at the Hotel de la Paix in Paris, just coming to from one of his peculiar sleeping spells. In this “recollection,” he saw himself being handed a dispatch bearing the sad news that his mother was dying.
A curious fact about this period of partial amnesia, Tesla later wrote, was that he was alive to everything touching on his research, which went forward apace. “I could recall the smallest details and the least significant observations in my experiments, and even recite pages of texts and complex mathematical formulae.”
It appears there had been reason for his concerns about his mother’s health: letters had been arriving from the family home at Gospic indicating that her health was indeed failing. He had also been receiving from all parts of the world invitations, honors, “and other flattering inducements” to visit and lecture. At last he accepted those from London and Paris, planning thereafter to go directly home.
His lecture to the Institution of Electrical Engineers in London was hailed as a major scientific event, and when it was over, the British did not want to let him go.
“Sir James Dewar insisted on my appearing before the Royal Society,” he recalled. “I was a man of firm resolve but succumbed easily to the forceful arguments of the great Scotchman. He pushed me into a chair and poured out half a glass of wonderful brown fluid which sparkled in all sorts of iridescent colors and tasted like nectar.”
To his surprise Dewar said, “Now you are sitting in Faraday’s chair and you are enjoying whiskey he used to drink.”2 On being assured that no one else in the world more deserved these honors, he was won over. The French could wait one more day.
His lecture before the Royal Society of Great Britain, attended by the elite of the scientific world, brought yet more accolades for the young inventor. Lord Rayleigh, the distinguished physicist who was then chairman of the Royal Society, urged the inventor, because of his great talent for mining fundamental discoveries, to consider revising his modus operandi.
He recommended that Tesla in the future specialize in some single area of research. This was a highly novel idea for a scientist who demanded all the answers at once.
Sir William Crookes, whose work Tesla greatly admired, sent a letter to his hotel after the lecture, describing how he had been inspired to subject his own body to strange electrical effects.
“My dear Tesla,” he wrote. “You are a true prophet. I have finished my new coil, and it does not do so well as the little one you made for me. I fear it is too large…. The phosphorescence through my body when I hold one terminal is decidedly inferior to that given with the little one….”3
The observant Crookes had noted the inventor’s exhaustion and went on to warn him that he appeared to be on the verge of a physical and nervous breakdown. “I hope you will get away to the mountains of your native land as soon as you can,” he wrote. “You are suffering from overwork, and if you do not take care of yourself, you will break down. Don’t answer this letter or see anyone but take the first train.”
Sir William was right; but his advice was just then impossible for Tesla to accept.
The inventor hurried to Paris where he lectured on “Experiments with Alternating Currents of High Potential and High Frequency” and again demonstrated his sensitive electronic tubes. This time his audiences were the Société Internationale des Electriciens and the Société Française de Physique.
That same month of February 1892, Sir William Crookes affirmed Tesla’s intuition. He published a prediction that electromagnetic waves in space could be used for wireless.
No sooner had Tesla finished his last lecture than, pleading exhaustion, he fled to his room at the Hotel de la Paix. It seemed almost an anticlimax when a messenger handed him a telegram saying that his mother was dying.
Rushing to the station, he squeezed aboard a train just leaving for Croatia. Later transferring to a carriage, he reached home in time to spend a few hours with his mother. Then, near collapse, he was taken to a building close to his home to rest.
“As I lay helpless there,” he wrote in his autobiographical memoir, “I thought that if my mother died while I was away from her bedside she would surely give me a sign…. I [had been
] in London in company with my late friend, Sir William Crookes, when spiritualism was discussed, and I was under the full sway of these thoughts…. I reflected that the conditions for a look into the beyond were most favorable, for my mother was a woman of genius and particularly excelling in the powers of intuition.”4
During that entire night his mind was strained with expectancy, but nothing happened until early in the morning. In a light dream or “swoon,” he says, he saw “a cloud carrying angelic figures of marvelous beauty, one of whom gazed upon me lovingly and gradually assumed the features of my mother. The appearance slowly floated across the room and vanished, and I was awakened by an indescribably sweet song of many voices. In that instant a certitude, which no words can express, came upon me that my mother had just died. And that was true….”
It was important to him later to account for the external causes of these apparently trancendental impressions, since he still held to his thesis that human beings were mere “meat machines.” The following “explanation” appears in his memoir:
“When I recovered I sought for a long time the external cause of this strange manifestation and, to my great relief, I succeeded after many months of fruitless effort. I had seen the painting of a celebrated artist, representing allegorically one of the seasons in the form of a cloud with a group of angels which seemed to actually float in the air, and this had struck me forcefully. It was exactly the same that appeared in my dream, with the exception of my mother’s likeness. The music came from the choir in the church nearby at the early mass of Easter morning, explaining everything satisfactorily in conformity with scientific facts.
“This occurred long ago, and I have never had the faintest reason since to change my views on psychical and spiritual phenomena, for which there is absolutely no foundation. The belief in these is the natural outgrowth of intellectual development. Religious dogmas are no longer accepted in their orthodox meaning, but every individual clings to faith in a supreme power of some kind. We all must have an ideal to govern our conduct and insure contentment, but it is immaterial whether it be one of creed, art, science or anything else, so long as it fulfills the function of a dematerializing force. It is essential to the peaceful existence of humanity as a whole that one common conception should prevail.
“While I have failed to obtain any evidence in support of the contentions of psychologists and spiritualists, I have proved to my complete satisfaction the automatism of life, not only through continuous observations of individual actions, but even more conclusively through certain generalizations.”5
He said that whenever friends or relatives of his had been hurt by others in a particular way, he himself felt what he could only characterize as a “cosmic” pain. This resulted from the fact that human bodies are of similar construction and exposed to the same external influences, which results in likeness of response. “A very sensitive and observant being, with his highly developed mechanism all intact, and acting with precision in obedience to the changing conditions of the environment,” he wrote, “is endowed with a transcending mechanical sense, enabling him to evade perils too subtle to be directly perceived. When he comes in contact with others whose controlling organs are radically faulty, that sense asserts itself and he feels the ‘cosmic’ pain….”6
It is obvious from the inventor’s writings that he himself was never completely satisfied with his theories on this subject.
This was not to be the only instance of precognition and extrasensory perception in Tesla’s life. But he always tried to explain them away mechanistically, tracing intuition to external events. Thus when his sister Angelina fell fatally ill, he sent a telegram from New York saying, “I had a vision that Angelina was arising and disappearing. I sensed all is not well.” Tesla’s nephew, Sava Kosanović would later recall how the inventor told him of such premonitions but discounted them. He was a sensitive receiver, he said, registering any disturbance—but there was no mystery to it.
“He declared,” said Kosanović, “that each man is like an automaton which reacts to external impressions.” But what the external impressions were that gave him actual precognition, as hereafter described, he never discussed.
He told Kosanović of an incident that occurred in Manhattan in the 1890s after he had given a big party. Some of the guests were preparing to take a train for Philadelphia. Tesla, seized with “a powerful urge,” was impelled to detain them, causing them to miss the train. It crashed. Many passengers were injured.7
He associated a personal anomaly with the anxious rush to his mother’s deathbed. A patch of white hair developed on the right side of his head, which was otherwise jet black and thick. After a few months, however, it returned to its natural state.
Following his mother’s death he was ill for a number of weeks. When finally able to get about, he visited relatives in Belgrade, where he received the welcome due a world-famous native son, and then went on to Zagreb and Budapest.
As a child Tesla had been fascinated by the relationship between lightning and rain. On this trip, while roaming in his native mountains, he had an experience that profoundly affected him as a scientist.
“I sought shelter from an approaching storm,” he later recalled. “The sky became overhung with dark clouds but somehow the rain was delayed until, all of a sudden, there was a lightning flash and a few moments after, a deluge. This observation set me thinking. It was manifest that the two phenomena were closely related, as cause and effect, and a little reflection led me to the conclusion that the electrical energy enclosed in the precipitation of the water was inconsiderable, the function of lightning being much like that of a sensitive trigger.
“Here was a stupendous possibility of achievement. If we could produce electric storms of the required ability, this whole planet and the conditions of existence on it could be transformed. The sun raises the water of the oceans and winds drive it to distant regions where it remains in a state of the most delicate balance. If it were in our power to upset it when and wherever desired, this mighty life-sustaining medium could be at will controlled. We could irrigate arid deserts, create lakes and rivers and provide motive power in unlimited amounts.”
Controlling lightning, he concluded, would be the most convenient way of harnessing the power of the sun.
“The consummation depended on our ability to develop electric forces of an order of those in nature,” he decided. “It seemed a hopeless undertaking, but I made up my mind to try. [I]mmediately upon my return to the United States, in the summer of 1892, work was begun which was to me all the more attractive, because a means of the same kind was necessary for the successful transmission of energy without wires.”8
On August 31, 1892, The Electrical Engineer reported the return to New York of Mr. Nikola Tesla, the distinguished electrician, on the steamship Augusta Victoria from Hamburg. After commenting on the death of Tesla’s mother and his subsequent illness, the journal added: “His magnificent reception at the hands of European electricians has become, like his investigations and researches, part of electrical history; and the honors conferred on him were such as to make Americans very proud of one who has chosen this country as a home.”
He moved scientific history forward again in the spring of 1893 when, addressing the Franklin Institute in Philadelphia and the National Electric Light Association at St. Louis, he described in detail the principles of radio broadcasting.
At St. Louis he made the first public demonstration ever of radio communication, although Marconi is generally credited with having achieved this feat in 1895.
Tesla’s twenty-eight-year-old assistant at the St. Louis lecture was H. P. Broughton, whose son, William G. Broughton, is licensee of the Schenectady Museum memorial amateur radio station W21R. At the station’s dedication speech in 1976 William Broughton touched upon highlights of Tesla’s historic demonstration at St. Louis—after a week’s preparation—as personally told to him by his father.
“Eighty-three years ago, in St. Louis, the
National Electric Light Association sponsored a public lecture on high-voltage high-frequency phenomena,” said the younger Broughton. “On the auditorium stage a demonstration was set up by using two groups of equipment.
“In the transmitter group on one side of the stage was a 5-kva high-voltage pole-type oil-filled distribution transformer connected to a condenser bank of Leyden jars, a spark gap, a coil, and a wire running up to the ceiling.
“In the receiver group at the other side of the stage was an identical wire hanging from the ceiling, a duplicate condenser bank of Leyden jars and coil—but instead of the spark gap, there was a Geissler tube that would light up like a modern fluorescent lamp bulb when voltage was applied. There were no interconnecting wires between transmitter and receiver.
“The transformer in the transmitter group,” Broughton continued, “was energized from a special electric power line through an exposed two-blade knife switch. When this switch was closed, the transformer grunted and groaned, the Leyden jars showed corona sizzling around their foil edges, the spark gap crackled with a noisy spark discharge, and an invisible electromagnetic field radiated energy into space from the transmitter antenna wire.
“Simultaneously, in the receiver group, the Geissler tube lighted up from radio-frequency excitation picked up by the receiver antenna wire.
“Thus wireless was born. A wireless message had been transmitted by the 5-kilowatt spark transmitter, and instantly received by the Geissler-tube receiver thirty feet away….
“The world-famous genius who invented, conducted, and explained this lecture demonstration,” he concluded, “was Nikola Tesla.”
Although the St. Louis demonstration was no “message sent ’round the world” as Tesla would doubtless of course have preferred it to be, he had nevertheless demonstrated all the fundamental principles of modern radio: 1. an antenna or aerial wire; 2. a ground connection; 3. an aerial-ground circuit containing inductance and capacity; 4. adjustable inductance and capacity (for tuning); 5. sending and receiving sets tuned to resonance with each other; and 6. electronic tube detectors.9