Nikola Tesla

Nikola Tesla, (July 9, 1856 – January 7, 1943) a Serbian immigrant, inventor, physicist, and electrical engineer moved to the Americas in 1884, where his inventions catapulted our civilization into the new age. He was the greatest genius of the 19th century if not the greatest genius of all time.

Tesla was determined to provide free energy to everyone on the planet. He was very aware of the effects his inventions could have on humanity if they were to fall in the wrong hands.

Nikola Tesla was greatly influenced by Vedic philosophy, and thus the realization that Reality is a Dynamic Unity. He found ways to transfer energy through Space using resonance, based upon his belief that Space existed and propagated waves.

Nikola Tesla was a pioneer in a staggering number of fields; AC power was only one of them. He has also done significant research and development in a wide variety of other disciplines, and his body of over 700 patents ranges through such diverse fields as robotics, wireless communications, turbines, fluid dynamics, radar, therapeutic equipment, VTOL aircraft, artificial lighting, X-rays, and computer systems.

EARLY YEARS

Tesla was born to a Serbian family in the village of Smiljan near Gospic, in the Lika region in Krajina, Croatia (then part of the Austrian Empire). According to legend, he was born precisely at midnight during an electrical storm.

His father was Rev. Milutin Tesla, a priest in the Serbian Orthodox Church Metropolitanate of Sremski Karlovci. His mother was Duka Mandic, herself a daughter of a Serbian Orthodox Church priest. She came from a family domiciled in Lika and Banija, but with deeper origins to Kosovo. She was talented in making home craft tools. She memorized many Serbian epic poems, but never learned to read.

Tesla studied electrical engineering at the Austrian Polytechnic in Graz (1875). While there, he studied the uses of alternating current.

Tesla was later persuaded by his father to attend the Charles-Ferdinand University in Prague, which he attended for the summer term of 1880. Here he was influenced by Ernst Mach. However, after his father died he left the university, having completed only one term.

Tesla engaged in reading many works, memorizing complete books, supposedly having a photographic memory. Tesla related in his autobiography that he experienced detailed moments of inspiration. During his early life, Tesla was stricken with illness time and time again. He suffered a peculiar affliction in which blinding flashes of light would appear before his eyes, often accompanied by hallucinations. Much of the time the visions were linked to a word or idea he might have come across; just by hearing the name of an item, he would involuntarily envision it in realistic detail. Modern-day synesthetes report similar symptoms. Tesla would visualize an invention in his brain in precise form before moving to the construction stage; a technique sometimes known as picture thinking. Tesla also often had flashbacks to events that had happened previously in his life; this began to happen during childhood.

HUNGARY AND FRANCE

In 1881, he moved to Budapest, Hungary, to work under Tivadar Puskas in a telegraph company, the National Telephone Company. There, he met Nebojsa Petrovic, a young inventor from Austria. Although their encounter was brief, they did work on a project together using twin turbines to create continual power. On the opening of the telephone exchange in Budapest, 1881, Tesla became the chief electrician to the company, and was later engineer for the country’s first telephone system. He also developed a device that, according to some, was a telephone repeater or amplifier, but according to others could have been the first loudspeaker.

In 1882 he moved to Paris, France, to work as an engineer for the Continental Edison Company, designing improvements to electric equipment. In the same year, Tesla conceived the induction motor and began developing various devices that use rotating magnetic fields (for which he received patents in 1888).

UNITED STATES

On June 6, 1884, Tesla first arrived in the US in New York City. He had little besides a letter of recommendation from Charles Batchelor, his manager in his previous job. In the letter of recommendation to Thomas Edison, Charles Batchelor wrote, ‘I know two great men and you are one of them; the other is this young man.’ Edison hired Tesla to work for his company Edison Machine Works. Tesla’s work for Edison began with simple electrical engineering and quickly progressed to solving the company’s most difficult problems. Tesla was offered the task of a complete redesign of the Edison Company’s direct current generators.

During his employment, Tesla claims Edison offered him $50,000 (equivalent to about $1 million in 2006, adjusted for inflation if he redesigned Edison’s inefficient motor and generators, an improvement in both service and economy.

Tesla said he worked night and day to redesign them and gave the Edison Company several profitable new patents in the process. During the year of 1885, when Tesla inquired about the payment on the work, Edison replied to him, ‘Tesla, you don’t understand our American humor,’ and reneged on his promise. This anecdote is somewhat doubtful, since at Tesla’s salary of $18 per week the bonus would have amounted to over 53 years pay, and the amount was equal to the initial capital of the company. Tesla resigned when he was refused a raise to $25 per week.

Tesla eventually found himself digging ditches for a short period of time – coincidentally for the Edison Company. Edison had also never wanted to hear about Tesla’s AC polyphase designs, believing that DC electricity was the future. Tesla focused intently on his AC polyphase system, even while digging ditches.

MIDDLE YEARS

In 1886, Tesla formed his own company, Tesla Electric Light & Manufacturing. The initial financial investors disagreed with Tesla on his plan for an alternating current motor and eventually relieved him of his duties at the company. Tesla worked in New York as a common laborer from 1886 to 1887 to feed himself and raise capital for his next project.

In 1887, he constructed the initial brushless alternating current induction motor, which he demonstrated to the American Institute of Electrical Engineers (now IEEE) in 1888. In the same year, he developed the principles of his Tesla coil and began working with George Westinghouse at Westinghouse Electric & Manufacturing Company’s Pittsburgh labs. Westinghouse listened to his ideas for polyphase systems which would allow transmission of alternating current electricity over large distances.

In April of 1887, Tesla began investigating what would later be called X-rays using his own single node vacuum tubes (similar to his patent #514,170).

In the early research, Tesla devised several experimental setups to produce X-rays. He continued research in the field and, later, observed an assistant severely ‘burnt’ by X-rays in his lab. He performed several experiments prior to Roentgen’s discovery (including photographing the bones of his hand; later, he sent these images to Roentgen) but didn’t make his findings widely known; much of his research was lost in the 5th Avenue lab fire of March 1895.

A ‘world system’ for ‘the transmission of electrical energy without wires’ that depends upon the electrical conductivity was proposed in which transmission in various natural mediums with current that passes between the two points are used to power devices. In a practical wireless energy transmission system using this principle, a high-power ultraviolet beam might be used to form a vertical ionized channel in the air directly above the transmitter-receiver stations. The same concept is used in virtual lightning rods, the electrolaser electroshock weapon, and has been proposed for disabling vehicles.

Tesla demonstrated ‘the transmission of electrical energy without wires’ that depends upon electrical conductivity as early as 1891. The Tesla effect (named in honor of Tesla) is the archaic term for an application of this type of electrical conduction (that is, the movement of energy through space and matter; not just the production of voltage across a conductor).

On July 30, 1891, he became a naturalized citizen of the United States at the age of 35. Tesla established his 35 South Fifth Avenue laboratory in New York during this same year. Later, Tesla would establish his Houston Street laboratory in New York at 46 E. Houston Street. There, at one point while conducting mechanical resonance experiments with electro-mechanical oscillators he generated a resonance of several surrounding buildings but, due to the frequencies involved, not his own building, causing complaints to the police.

As the speed grew he hit the resonant frequency of his own building ,and belatedly realizing the danger, he was forced to apply a sledge hammer to terminate the experiment, just as the astonished police arrived. He also lit vacuum tubes wirelessly at both of the New York locations, providing evidence for the potential of wireless power transmission.

When Tesla was 36 years old, the first patents concerning the polyphase power system were granted. He continued research of the system and rotating magnetic field principles.

From 1893 to 1895, he investigated high frequency alternating currents. He generated AC of one million volts using a conical Tesla coil and investigated the skin effect in conductors, designed tuned circuits, invented a machine for inducing sleep, cordless gas discharge lamps, and transmitted electromagnetic energy without wires, building the first radio transmitter. Tesla also investigated harvesting energy that is present throughout space. He believed that it was just merely a question of time when men will succeed in attaching their machinery to the very wheel-work of nature.

WIRELESS AND THE AIEE

Tesla served as the Vice-President of the American Institute of Electrical Engineers (now part of the IEEE) from 1892 to 1894.

In St. Louis, Missouri, Tesla made a demonstration related to radio communication (he demonstrated radio energy crossing space (one side of a stage to the other) in 1893.

Tesla held over forty U.S. patents (circa 1888) covering our entire system of Polyphase Alternating Current (AC). These patents are so novel that nobody could ever challenge them in the courts.

Tesla’s four-tuned circuits (two on the receiving side and two on the transmitting side, secured by U.S. patents #645,576 and #649,621) were the basis of the U.S. Supreme Court decision (Case #369 decided June 21, 1943) to overturn Marconi’s basic patent on the invention of radio.

• Alternating-current power transmission
• The Death Ray Machine
• Fluorescent lights
• Induction motor
• Polyphase alternating-current system
• Radio
• Rotating magnetic field principle
• Telephone repeater
• Tesla coil transformer
• Wireless communication

WORLD’S FAIR EXPOSITION

At the 1893 World’s Fair, the World Columbian Exposition in Chicago, Illinois, an international exposition was held which for the first time devoted a building to electrical exhibits. It was a historic event as Tesla and George Westinghouse introduced visitors to AC power by using it to illuminate the Exposition. In protest, Edison would not allow use of any of his light bulbs for this event.

As if lighting the Exposition was not enough, Tesla explained the principles of the rotating magnetic field and induction motor by demonstrating how to make an egg (made of copper) stand on end in his version of the Egg of Columbus.

WAR OF CURRENTS

In the ‘War of Currents’ era in the late 1880s, Nikola Tesla and Thomas Edison became adversaries due to Edison’s promotion of direct current (DC) for electric power distribution over the more efficient alternating current (AC) advocated by Tesla.

1896-1899

When Tesla was 41 years old, he filed the first basic radio patent (No. US645576). A year later, he demonstrated a remote controlled boat to the US military, believing that the military would want things such as radio-guided torpedoes. In 1898 a radio controlled boat was also demonstrated to the public during an electrical exhibition at Madison Square Garden. These devices had an innovative coherer and a series of logic gates. Radio remote control remained a novelty until the Space Age. In the same year, Tesla devised an electric igniter for gasoline engines which was nearly identical to ideas about the same process used by modern internal combustion engines.

In 1896, according to an interview he gave in 1916, Tesla invented a type of loudspeaker. The sounds were of the quality of the telephones of that time. The invention was never patented nor released publicly (till years later by Tesla himself).

As a result of the ‘War of Currents’ Edison and Westinghouse were almost bankrupt, so in 1897 Tesla released Westinghouse from contract providing Westinghouse a break from Tesla’s AC motor royalties.

COLORADO SPRINGS

In 1899, Tesla decided to move and began research in Colorado Springs, Colorado, where he could have room for his high-voltage high-frequency experiments. He chose this location primarily because of the frequent thunderstorms, the high altitude (where the air, being at a lower pressure, had a lower dielectric breakdown strength, making it easier to ionize), and the dryness of the air (minimizing leakage of electric charge through insulators). Also, the property was free and electric power available from the El Paso Power Company. Today, magnetic intensity charts also show that the ground around his lab possesses a denser magnetic field than the surrounding area. Tesla reached Colorado Springs on May 17, 1899. Upon his arrival he told reporters that he was conducting experiments transmitting signals from Pikes Peak to Paris.

Tesla kept a diary of his experiments in the Colorado Springs lab where he spent nearly nine months. It consists of 500 pages of handwritten notes and nearly 200 drawings, recorded chronologically between June 1, 1899 and January 7, 1900, as the work occurred, containing explanations of his experiments. He was developing a system for wireless telegraphy, telephony and the transmission of power, experimented with high-voltage electricity and the possibility of wireless transmitting and distributing large amounts of electrical energy over long distances. He also conceived a system for geophysical exploration–seismology–which he called telegeodynamics, based on his reciprocating mechanical oscillator patented in 1894, and explained that a long sequence of small explosions could be used to find ore and create earthquakes large enough to destroy the Earth. He did not experiment with this as he felt there would not be ‘a desirable outcome’.

Much of what Tesla discovered while in this lab has been lost to history and Tesla’s own secrecy. To this very day there is talk of Tesla’s Death Ray being invented there as well as communication with other planets. How much of this is true is now unknown, but has made Tesla’s time at this remote lab a wellspring for Urban legends about him.

LATER YEARS

In 1900, with US$150,000 (51 % from J. Pierpont Morgan), Tesla began planning the Wardenclyffe Tower facility. In June 1902, Tesla’s lab operations were moved to Wardenclyffe from Houston Street. The tower was finally dismantled for scrap during World War I. Newspapers of the time labeled Wardenclyffe ‘Tesla’s million-dollar folly’. In 1904, the US Patent Office reversed its decision and awarded Guglielmo Marconi the patent for radio, and Tesla began his fight to re-acquire the radio patent. On his 50th birthday in 1906, Tesla demonstrated his 200 hp (150 kW) 16,000 rpm bladeless turbine. During 1910-1911 at the Waterside Power Station in New York, several of his bladeless turbine engines were tested at 100-5000 hp.

Since the Nobel Prize in Physics was awarded to Marconi for radio in 1909, Thomas Edison and Tesla were mentioned as potential laureates to share the Nobel Prize of 1915 in a press dispatch, leading to one of several Nobel Prize controversies.

In 1915, Tesla filed a lawsuit against Marconi attempting, unsuccessfully, to obtain a court injunction against Marconi’s claims. After Wardenclyffe, Tesla built the Telefunken Wireless Station in Sayville, Long Island. Some of what he wanted to achieve at Wardenclyffe was accomplished with the Telefunken Wireless. In 1917, the facility was seized and torn down by the Marines, because it was suspected that it could be used by German spies.

Before World War I, Tesla looked overseas for investors to fund his research. When the war started, Tesla lost the funding he was receiving from his patents in European countries.

At this time, he was staying at the Waldorf-Astoria Hotel, renting in an arrangement for deferred payments. Eventually, the Wardenclyffe deed was turned over to George Boldt, proprietor of the Waldorf-Astoria, to pay a US$20,000 debt. In 1917, around the time that the Wardenclyffe Tower was demolished by Boldt to make the land a more viable real estate asset, Tesla received AIEE’s highest honor, the Edison Medal.

Tesla, in August 1917, first established principles regarding frequency and power level for the first primitive RADAR units.[72] In 1934, ‘mile Girardeau, working with the first French RADAR systems, stated he was building RADAR systems ‘conceived according to the principles stated by Tesla’. By the 1920s, Tesla was reportedly negotiating with the United Kingdom government about a ray system. Tesla had also stated that efforts had been made to steal the so called ‘death ray’. It is suggested that the removal of the Chamberlain government ended negotiations.

On Tesla’s seventy-fifth birthday in 1931, Time magazine put him on its cover. The cover caption noted his contribution to electrical power generation. Tesla received his last patent in 1928 for an apparatus for aerial transportation which was the first instance of VTOL aircraft. By the end of 1931, Tesla released ‘On Future Motive Power’ which covered an ocean thermal energy conversion system. In 1934, Tesla wrote to consul Jankovi_ of his homeland. The letter contained a message of gratitude to Mihajlo Pupin who had initiated a donation scheme by which American companies could support Tesla. Tesla refused the assistance, choosing instead to live on a modest pension received from Yugoslavia, and to continue his research.

MAGNIFYING TRANSMITTER

The lab possessed the largest Tesla Coil ever built, fifty-two feet (16 m) in diameter, known as the Magnifying Transmitter (further MT). Not identical to a classic Tesla Coil, it was a three-coil magnifying system requiring different forms of analysis than lumped-constant coupled resonant coils presently described to most. It resonated at a natural quarter wavelength frequency and could work in a continuous-wave mode and in a partially damped-wave resonant mode.

According to accounts, Tesla used it to transmit tens of thousands of watts of power wirelessly; it could generate millions of volts of electricity and produce lightning bolts more than one-hundred feet (30 m) long.

Tesla became the first man to create electrical effects on the scale of lightning. The MT produced thunder which was heard as far away as Cripple Creek. People near the lab would observe sparks emitting from the ground to their feet and through their shoes. Some have observed electrical sparks from the fire hydrants (Tesla for a time grounded out to the plumbing of the city). The area around the laboratory would glow with a blue corona (similar to St. Elmo’s Fire).

One of Tesla’s experiments with the MT destroyed Colorado Springs Electric Company’s generator by backfeeding the city’s power generators, and blacked out the city. The company denied Tesla further access to the backup generator’s feed if he did not repair the primary generator at his own expense; it was working again in a few days.

TUNED CIRCUITS

Tesla also constructed many smaller resonance transformers and discovered the concept of tuned electrical circuits. He also developed a number of coherers for separating and perceiving electromagnetic waves and designed rotating coherers which he used to detect the unique types of electromagnetic phenomenon he observed. They had a mechanism of geared wheels driven by a coiled spring-drive mechanism which rotated small glass cylinders. These experiments were the final stage of years of work on synchronized tuned electrical circuits.

These transceivers were constructed to demonstrate how signals could be ‘tuned in’. Tesla logged in his diary on July 3, 1899 that a separate resonance transformer tuned to the same high frequency as a larger high-voltage resonance transformer would transceive energy from the larger coil, acting as a transmitter of wireless energy, which was used to confirm Tesla’s patent for radio during later disputes in the courts. These air core high-frequency resonate coils were the predecessors of systems from radio to radar and medical magnetic resonance imaging devices.

PROPAGATION AND RESONANCE

On July 3, 1899, Tesla discovered terrestrial stationary waves within the earth. He demonstrated that the Earth behaves as a smooth polished conductor and possesses electrical vibrations. He experimented with waves characterized by a lack of vibration at points, between which areas of maximum vibration occur periodically. These standing waves were produced by confining waves within constructed conductive boundaries. Tesla demonstrated that the Earth could respond at predescribed frequencies of electrical vibrations. At this time, Tesla realized that it was possible to transceive power around the globe. A few years later, George Westinghouse stopped funding Tesla’s research when Tesla showed him that he could offer free electricity to the whole world by simply ‘ramming a stick in the earth in your backyard’. Westinghouse said he would go bankrupt if that happened.

Tesla conducted experiments contributing to the understanding of electromagnetic propagation and the Earth’s resonance. It is well documented (from various photos from the time) that he lit hundreds of lamps wirelessly at a distance of up to twenty-five miles (40 km). He transmitted signals several kilometres and lit neon tubes conducting through the ground. He researched ways to transmit energy wirelessly over long distances. He transmitted extremely low frequencies through the ground in his experiments and made mathematical calculations and computations based on his experiments and discovered that the resonant frequency of the Earth was approximately 8 Hz (Hertz). In the 1950s, researchers confirmed resonant frequency was in this range (interesting to note, Theta brain waves also cycle in this range).

COSMIC WAVES

In the Colorado Springs lab, Tesla recorded what he concluded were extraterrestrial radio signals and announced his findings in some of the scientific journals of the time. His announcements and data were rejected by the scientific community who did not believe him. He notes measurements of repetitive signals from his receiver which are substantially different from the signals he had noted from storms and earth noise. Specifically, he later recalled that the signals appeared in groups of clicks 1, 2, 3, and 4 clicks together. He stated in the article ‘A Giant Eye to See Round the World’, of February 25, 1923, that:

‘Twenty-two years ago, while experimenting in Colorado with a wireless power plant, I obtained extraordinary experimental evidence of the existence of life on Mars. I had perfected a wireless receiver of extraordinary sensitiveness, far beyond anything known, and I caught signals which I interpreted as meaning 1–2–3–4. I believe the Martians used numbers for communication because numbers are universal.’

Clearly, Tesla felt the signal groups originated on the planet Mars. In 1996 Corum and Corum published an analysis of Jovian plasma torus signals which indicate that there was a correspondence between the setting of Mars at Colorado Springs, and the cessation of signals from Jupiter in the summer of 1899 when Tesla was there. Further, analysis by the Corums indicate that Tesla’s transceiver was sensitive in the 18 kHz gap in the Kennelly-Heaviside layer which would have allowed that reception from Jupiter. Therefore, there is evidence the signals Tesla noticed came from Jupiter, among other possible sources. Tesla spent the latter part of his life trying to signal Mars.

It is important to recognize that when he says he ‘recorded’ these signals, it is meant that he wrote down the data and his impressions of what he had heard. He did release reports at the time. Tesla’s initial announcement of the existence of extraterrestrial radio signals was in 1899. In March of 1907, Tesla wrote about signaling to Mars in Harvard Magazine and how it was a problem of electrical engineering. Additional descriptions come from remembrances twenty years later. All this was met with resistance and disbelief by his contemporaries.

COLORADO DEPARTURE

Tesla left Colorado Springs on January 7, 1900. The lab was torn down, broken up, and its contents sold to pay debts. The Colorado experiments prepared Tesla for his next project, the establishment of a wireless power transmission facility that would be known as Wardenclyffe. On March 21, 1900, Tesla was granted US685012 patent for the means for increasing the intensity of electrical oscillations.

FIELD THEORIES

When he was eighty-one, Tesla stated he had completed a dynamic theory of gravity. He stated that it was ‘worked out in all details’ and that he hoped to soon give it to the world. The theory was never published. At the time of his announcement, it was considered by the scientific establishment to exceed the bounds of reason. Some believe that Tesla never fully developed the Unified Field Theory.

The bulk of the theory was developed between 1892 and 1894, during the period that he was conducting experiments with high frequency and high potential electromagnetism and patenting devices for their utilization. It was completed, according to Tesla, by the end of the 1930s. Tesla’s theory explained gravity using electrodynamics consisting of transverse waves (to a lesser extent) and longitudinal waves (for the majority). Reminiscent of Mach’s principle.

DIRECTED-ENERGY WEAPON

Later in life, Tesla made some remarkable claims concerning a ‘teleforce’ weapon. The press called it a ‘peace ray’ or death ray.

In total, the components and methods included:

* An apparatus for producing manifestations of energy in free air instead of in a high vacuum as in the past. This, according to Tesla in 1934, was accomplished.

* A mechanism for generating tremendous electrical force. This, according to Tesla, was also accomplished.

* A means of intensifying and amplifying the force developed by the second mechanism.

* A new method for producing a tremendous electrical repelling force. This would be the projector, or gun, of the invention.

Tesla worked on plans for a directed-energy weapon between the early 1900s till the time of his death. In 1937, Tesla composed a treatise entitled ‘The Art of Projecting Concentrated Non-dispersive Energy through the Natural Media’ concerning charged particle beams. Tesla published the document in an attempt to expound on the technical description of a ‘superweapon that would put an end to all war’. This treatise of the particle beam is currently in the Nikola Tesla Museum archive in Belgrade. It described an open ended vacuum tube with a gas jet seal that allowed particles to exit, a method of charging particles to millions of volts, and a method of creating and directing nondispersive particle streams (through electrostatic repulsion).

Records of his indicate that it was based on a narrow stream of atomic clusters of liquid mercury or tungsten accelerated via high voltage (by means akin to his magnifying transformer). Tesla gave the following description concerning the particle gun’s operation:

[The nozzle would] send concentrated beams of particles through the free air, of such tremendous energy that they will bring down a fleet of 10,000 enemy airplanes at a distance of 200 miles from a defending nation’s border and will cause armies to drop dead in their tracks’

 

The weapon could be used against ground based infantry or for antiaircraft purposes. Tesla tried to interest the US War Department in the device. He also offered this invention to European countries. None of the governments purchased a contract to build the device. He was unable to act on his plans.

THEORETICAL INVENTIONS

Tesla began to theorize about electricity and magnetism’s power to warp, or rather change, space and time and the procedure by which man could forcibly control this power. Near the end of his life, Tesla was fascinated with the idea of light as both a particle and a wave, a fundamental proposition already incorporated into quantum physics.

This field of inquiry led to the idea of creating a ‘wall of light’ by manipulating electromagnetic waves in a certain pattern. This mysterious wall of light would enable time, space, gravity and matter to be altered at will, and engendered an array of Tesla proposals that seem to leap straight out of science fiction, including anti-gravity airships, teleportation, and time travel.

The single strangest invention Tesla ever proposed was probably the ‘thought photography’ machine. He reasoned that a thought formed in the mind created a corresponding image in the retina, and the electrical data of this neural transmission could be read and recorded in a machine. The stored information could then be processed through an artificial optic nerve and played back as visual patterns on a viewscreen.

Another of Tesla’s theorized inventions is commonly referred to as Tesla’s Flying Machine, which appears to resemble an ion-propelled aircraft. Tesla claimed that one of his life goals was to create a flying machine that would run without the use of an airplane engine, wings, ailerons, propellers, or an onboard fuel source. Initially, Tesla pondered about the idea of a flying craft that would fly using an electric motor powered by grounded base stations. As time progressed, Tesla suggested that perhaps such an aircraft could be run entirely electro-mechanically. The theorized appearance would typically take the form of a cigar or saucer.

DEATH

Tesla died of heart failure alone in Room 3327 of the New Yorker Hotel, sometime between the evening of January 5 and the morning of January 8, 1943, at the age of 86.[90] Despite selling his AC electricity patents, Tesla was destitute and died with significant debts. Later that year the US Supreme Court upheld Tesla’s patent number U.S. Patent 645,576 in effect recognizing him as the inventor of radio.

Immediately after Tesla’s death became known, the Federal Bureau of Investigation instructed the government’s Alien Property Custodian office to take possession of his papers and property, despite his US citizenship. His safe at the hotel was also opened.

At the time of his death, Tesla had been continuing work on the teleforce weapon, or death ray, that he had unsuccessfully marketed to the US War Department. It appears that his proposed death ray was related to his research into ball lightning and plasma and was imagined as a particle beam weapon.

The US government did not find a prototype of the device in the safe. After the FBI was contacted by the War Department, his papers were declared to be top secret. The so-called ‘peace ray’ constitutes a part of some conspiracy theories as a means of destruction. The personal effects were seized on the advice of presidential advisers, and J. Edgar Hoover declared the case ‘most secret’, because of the nature of Tesla’s inventions and patents. One document states that ‘[he] is reported to have some 80 trunks in different places containing transcripts and plans having to do with his experiments’. Charlotte Muzar reported that there were several ‘missing’ papers and property.