Tesla Coils

Nikola Tesla

In the morning of 30 June 1908, a brilliant flash lit the air against the Tuguska River in central Siberia. Seconds later, some 2,000 square kilometres of Russia vanished from the map, and over 200,000 hectares of pine forest went up in flames. Every living thing in the vicinity was destroyed. The explosion, reckoned to be equivalent to 10-15 megatons of TNT, was heard nearly 1000 km away. At first it was assumed to be a meteorite strike. But when experts examined the site in 1927 they found no impact crater, nor did they find any trace of meteoritic minerals, despite drilling sample cores to a depth of over 50 metres. It was a complete mystery. Since then, theories to explain the Tunguska incident have covered everything from alien spaceships to rogue black holes. There is, however, one other possibility. Evidence suggests that the Tukungska explosion might have been a trial run of Dr Nikola Tesla's 'death ray' apparatus.

THE INVENTOR:

Tesla was a man whose brilliant career still causes controversy. Born in Croatia in 1856, he spent his early years in Eastern Europe, where his extraordinary abilities soon gained him fame. He could speak six languages, had a photographic memory, was able to judge distances to a tenth of a millimetre with the naked eye, and perform difficult calculations without benefit of a slide-rule or tables. Above all he possesed quite sensational powers of visualisation. He could imagine a machine, construct it, test it, and rectify any faults all in his head. As a result, his inventions were invariably perfect the minute they were built.

Invention was Tesla's speciality - he saw no reason why his genius should not be put into practical purposes - and his chosen field was electricity, a science then in its fancy. From the start of his studies, he staggered professors by displaying an understanding of the subject that was greater than their own. Before long , he had far outstripped them.

By the time he left Europe for the US, he had drawn up plans for a motor based on rotating magnetic fields. That same 'induction motor' is used today in almost every industrial and domestic appliance.

Tesla arrived in the US in 1884, and went to work for Thomas Edison, a businessman who favoured sharp practices and expensive electricity. After a disagreement about royalties, the two men parted company. The break with Edison drove Tesla to abandon mainstream electrics. He moved to Colorado springs, near Denver, and persued more innovative avenues.

Tesla had a basic , but untested vision of electricity. He started that 'communication without wires to any part of the globe is practicable'. He theorised that the earth itself was a natural conductor - a tuning fork, almost - and could bounce electric waves sent from a central transmitter. These waves could be picked up by receivers placed anywhere around the globe.

Nobody believed him, so, in 1899, to prove his point , he built a transmitter that could also receive. From this structure, built on top of his laboratory, he hoped to bounce an electric wave around the world and pick it up again. Realizing that a single wave could lose strength during its journey, he planned to follow it up with succeeding pulses of electricity until he created a continuous cycle of increasing power.

THROWING THE SWITCH

The residents of Colorado Springs had become used to Dr Tesla's laboratory, with its weird, 60-metre-high mast topped by and iron globe. Many of them had seen Tesla himself light 200 bulbs, without the aid of wires, from a distance of 40 km. But they were not ready for what happened when Tesla threw the switch on his latest creation.

A spark of lightning emerged from the globe at the top of the tower. It grew steadily, until it was a solid bolt of electricity crackling 50 metres into the sky. Thunderclaps roared. The grass around the lab glowed a ghostly green. Fire hydrants gave off 10 cm sparks. The simple act of walking on that bizare day created a discharge that leaped and danced from foot to pavement. Even butterflies were surrounded by a ghastly aura that sent them spinning to the ground in confusion. The noise inside the lab was deafening. Sparks as thick as a man's arm shot across the room. Outside, on the eerie lawns, Dr Tesla surveyed his experiments from atop his rubber soled platform shoes.

Conditions returned to normal only when the power supply gave out - Tesla's experiment had melted the city generator. During that brief period of madness and mayhem, he created a record - Which still stands - for the longest man-made spark. But what would have happened had the power lasted?

DEATH RAY

According to Tesla's figures, his transmitter could produce power levels of up to 100 billion watts. Focused in a short burst on a single frequency this would produce a surge of 100,000,000,000,000,000 Joules of energy. This is equivalent to ten megatons of TNT, roughly the size of the Tunguska explosion. Effectively, the force of a nuclear detonation could be effectively directed anywhere in the world by radio waves.

He never got the chance to prove his point. In 1903, J.P. Morgan (a financier who invested $150,000 into Tesla's scheme) withdrew his support. True, there was a stock market crash that year. But perhaps, also, Morgan feared Tesla was getting out of control. A ten megatonne deathray was perfectly acceptable - but supplying the world with an unmetered supply of electricity was quite unthinkable. Also, as Edison and other was soon to point out, anyone wishing to transmit radio messages soon discovered that Marconi's method was much cheaper than Tesla's. In desperation Tesla turned to George Westinghouse, but he, like Morgan saw no profit in the scheme.

Tesla sank into dept. His Colorado Springs Laboratory was sold off to settle miserable claims -$180 for electricity, $928.57 for the caretaker's wages. By 1906 there was no money to pay Wardenclyffe's employees and the massive facility, with its enormous metal dome, lay empty.

Despite suffering a nervous breakdown, Tesla pressed ahead. As the world began the arms race that would eventually lead to World War I, he emphasised his invention's destructive potential.

Tesla neither claimed nor denied responsibility when, in 1907, the French ship Inea blew up under misterious circumstances. Certainly the Inea's destruction was in his capabilities. He had already stated that his transmitter could send waves of 'sufficient intensity to cause a spark in the ship's magazine and explode it'. The Wardenclyffe dome, although unmanned, was fully operational. All it would have needed was one man to throw the switch...

DESPERATE MEASURES

In April 1908 Tesla told a newspaper of his device's destructive effects. 'This is no dream', he said. 'Wireless plants could be constructed be which any region of the globe might be rendered uninhabitable.' Eight months later the Tunguska incident occurred. Was this a mere coincidence? Or was Tesla conducting a test run of his machine in an effort to gain backing for his work?

Curiously, this was the same year in which Robert Peary was starting his highly publicised expedition to discover the North Pole. Had Tesla wanted to bring his death ray to the world's attention there could have been no better way than to blast a hole across Peary's path.

Ellesmere Island, to the west of Greenland, was Peary's starting point for the polar journey. If a line is drawn from Long Island across the pole, Ellesmere and Tunguska lie within two degrees of each other. Did Tesla make the wrong measurements? A minuscule miscalculation at the point of delivery could have resulted in a massive overshoot. Or was the power simply too strong for him to handle? Either way, a publicist's dream coincided very neatly with an international mystery.

By 1915, however, Tesla still had no backers. That year he was forced to sell Wardenclyffe in order to pay his hotel bills. The installation was bulldozed for scrap in 1917.

FIGURE OF FUN

During the 1920s, Tesla sank into self-imposed obscurity. Ironically, that was the decade in which people began to take notice of his experiments. In 1924, a scientist by the name of H. Grindell-Matthews reported his invention of a 'diabolical ray' that was very similar to Tesla's. There were also rumours that the Soviets had developed an air-defence system based on electromagnetic principles. Suddenly, Tesla became news. He responded by issuing annual statements on 10 July (his birthday), describing his vision of future uses of electricity. These were so sensational that they became a figure of fun. As late as 1935 he was trying to interest J.P. Morgan in a defence system that used Star Trek-style particle beams.

Tesla died in 1943, defending his theories to the last. Shortly after his death, his laboratory burned down in misterious circumstances. His papers, meanwhile were confiscated by the US government. When they were later handed to his nephew, they conspicuously lacked any reference to his death ray. Of course, we need not think of it as a death ray. We might just as easily think of it as a means of supplying free electricity to all, and wonder why anyone, particularly the leading figures in the power supply business, should wish to suppress such an invention.

Tesla's lab in Wardenclyffe.

MODERN TESLA COILS:

A small Tesla Coil.

A medium sized Tesla Coil.

A big Tesla Coil.