Nikola Tesla (July 9/July 10, 1856 - January 7, 1943) was a physicist, inventor, and electrical engineer of unusual intellectual brilliance and practical achievement. He was of Serb descent and worked mostly in the United States.
Tesla is most famous for conceiving the rotating magnetic field principle (1882) and then using it to invent the induction motor together with the accompanying alternating current long-distance electrical transmission system (1888) . His theoretical work and patents still form the basis for modern alternating current electric power systems.
He also developed numerous other electrical and mechanical devices including the fundamental principles and machinery of wireless technology , including the high frequency alternator, the "AND" logic gate and the Tesla coil, as well as other devices such as the bladeless turbine, the spark plug and numerous other inventions.
- additional information available in Biography of Nikola Tesla
Tesla was born around midnight between July 9th and July 10th, 1856 in the village of Smiljan near Gospić, in the Lika region of the Military Frontier (Krajina) of the Habsburg Monarchy, now in Croatia. His baptism name was Николай (Nikola). His full name written in the Cyrillic alphabet is Никола Тесла.
His father, the Rev. Milutin Tesla , was a priest in the Serb Orthodox Metropolitanate of Karlovci. His mother, Đuka Mandić, made home craft tools. Tesla was one of five children, having one brother and three sisters.
Tesla went to school in Karlovac (then Austria-Hungary, now Croatia), then studied electrical engineering at the Austria Politechnic in Graz, Austria (1875). While there, he studied the uses of alternating current.
In 1881 he moved to Budapest to work for the telegraph company, American Telephone Company . On the opening of the telephone exchange in Budapest, 1881, Tesla became the chief electrician to the company, later engineer to the Yugoslav government and the country's first telephone system. He also developed a telephone repeater (or amplifier).
For a while he stayed in Maribor. He was employed at his first job as an assistant engineer. Tesla suffered a nervous breakdown during this time. In 1882 he moved to Paris to work as an engineer for the Continental Edison Company on 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). Tesla hastened from Paris to his mother's side as she lay dying, arriving hours before her death in 1882. After her death, Tesla fell ill. He spent two to three weeks recuperating at home near Gospić.
In 1884, leaving the warfare of his birthplace behind, Tesla moved to the United States of America to accept a job with the Edison Company in New York City. He arrived in the US with 4 cents to his name, a book of poetry, and a letter of recommendation (from Charles Batchelor, his manager in his previous job).
When Tesla first arrived in the United States, he was offered a job by Thomas Edison when the latter saw his letter of recommendation from Charles Batchelor which read simply "I know two great men and you are one of them. This young man is the other".
Tesla's work for Edison began with simple electrical engineering. Eventually Tesla earned the respect of Edison and offered to undertake a complete re-design of the Edison company's DC dynamos. After Tesla described the nature of the benefits from his proposed modifications, Edison offered him $50,000 if they were successfully completed. Tesla worked nearly a year to redesign them and gave the Edison company several enormously profitable new patents in the process. When Tesla inquired about the $50,000, Edison replied to him, "Tesla, you don't understand our American humor" and reneged on his agreement, offering a raise in Tesla's salary of $10 per week as a compromise - at which rate it would have taken almost 100 years to earn the money Edison had originally promised. Tesla resigned on the spot. In some accounts of the final confrontation, he didn't say a single word to Edison but simply turned his back on the inventor and walked off the premises.
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 alternate-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's Pittsburgh labs. Westinghouse listened to his ideas for polyphase systems which would allow transmission of AC electricity over large distances.
X-rays and friendships
In April 1887, Tesla began investigating what would later be called X-rays using his own single node vacua tubes (similar to his US514170 patent). This device differed from other early X-ray tubes in that they had no target electrode. The modern term for the phenomena produced from this device is termed the bremsstrahlung process. He also used Crookes tubes.
On July 30, 1891, he became a naturalized citizen of the United States and established his Houston Street laboratory in New York. He lit vacuum tubes wirelessly in it, providing evidence for the potential of wireless power transmission. Around this time, Tesla developed a close and lasting friendship with Mark Twain. They spent a lot of time together in Tesla's lab and elsewhere. Tesla's closest friends were artists. He also befriended R. A. Jonson , who adapted several Serbian poems of Jovan Jovanović Zmaj (which Tesla translated).
When he 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. By 1892, Tesla became aware of what Wilhelm Röntgen later identified as effects of X-rays. He performed several experiments (including photographing the bones of his hand; later, he sent these images to Röntgen) but didn't make his findings widely known; much of his research was lost in the 1895 Houston Street lab fire.
Tesla commented on the hazards of working with single node x-ray producing devices, attributing the skin-damage to ozone rather than the radiation: "As to the hurtful actions on the skin... I note that they have been misinterpreted... They are not due to the Roentgen rays, but merely to the ozone generated in contact with the skin. Nitrous acid may also be responsible, but to a small extent." (Tesla, in Electrical Review, 30 November 1895). This is incorrect concerning cathodic x-ray tubes. Tesla later observes an assistant severly "burnt" by x-rays in his lab.
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. 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, effectively building the first radio transmitter.
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. Addressing the Franklin Institute in Philadelphia, Pennsylvania and the National Electric Light Association, he described and demonstrated in detail its principles. Heinrich Hertz had made such demonstrations, repeatedly, five years previously. Hertz' demonstrations were not public (they were conducted during his physics lectures) but strictly speaking neither were Tesla's (the Franklin Institute didn't open to the general public until 1934).
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 lightbulbs 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.
Tesla Memorial at Niagara Falls
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. See War of Currents for more details.
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 controled 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.
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 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.
Tesla, a local contractor, and several assistants commenced the construction of the laboratory shortly after arriving in Colorado Springs. The lab was established on Knob Hill , east of the Colorado School for the Deaf and Blind and one mile (1.6 km) east of downtown. Its primary purpose were experiments with high frequency electricity and other phenomena, and secondary--research into wireless transmission of electrical power.
Tesla's design of the lab was a building fifty feet by sixty feet (15 by 18 m) with eighty-foot (24 m) ceilings. A one-hundred-forty-two foot (43 m) conducting aerial with a thirty-inch (760 mm) copper-foil-covered wooden ball was erected on the roof. The roof was rolled back to prevent fire from sparks and other dangerous effects of the experiments. The laboratory had sensitive instruments and equipment.
publicity photo of Tesla sitting in his laboratory in Colorado Springs with his "magnifying transmitter" generating millions of volts of electricity. The arcs are about 22 feet (7 m) long.
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 posted a large fence around it with a sign "Keep Out - Great Danger".
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.
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 the 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).
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." Albany Telegram — February 25, 1923 
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.
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.
Main article: Wardenclyffe Tower
In 1900, with $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. Among the various application of the 700-plus patents accumulated by Tesla, the most controversial today is his Wardenclyffe Tower. The tower was billed as the start of a global system for wireless telecommunications but was also intended by Tesla as a demonstration of wireless electrical power distribution. In 1903, upon hearing of Tesla's plans for wireless power transmission, Morgan refused any more funding to support the Wardenclyffe Tower project. The tower was finally dismantled for scrap during wartime. Newspapers of the time labeled Wardenclyffe "Tesla's million-dollar folly."
In the article "The Future of the Wireless Art" which appeared in Wireless Telegraphy & Telephony , 1908, Tesla made the following statement regarding the Wardenclyffe project:
"As soon as completed, it will be possible for a business man in New York to dictate instructions, and have them instantly appear in type at his office in London or elsewhere. He will be able to call up, from his desk, and talk to any telephone subscriber on the globe, without any change whatever in the existing equipment. An inexpensive instrument, not bigger than a watch, will enable its bearer to hear anywhere, on sea or land, music or song, the speech of a political leader, the address of an eminent man of science, or the sermon of an eloquent clergyman, delivered in some other place, however distant. In the same manner any picture, character, drawing, or print can be transferred from one to another place. Millions of such instruments can be operated from but one plant of this kind. More important than this, however, will be the transmission of power, without wires, which will be shown on a scale large enough to carry conviction. These few indications will be sufficient to show that the wireless art offers greater possibilities than any invention or discovery heretofore made, and if the conditions are favorable, we can expect with certitude that in the next few years wonders will be wrought by its application."
Fight for Radio Patent
In 1904, the US Patent Office reversed itself and awarded Guglielmo Marconi the patent for radio. Tesla began his fight to re-acquire his radio patent. Later in 1907, Marconi was awarded the Nobel Prize for radio. Tesla was deeply resentful. So in 1915, Tesla filed a lawsuit against Marconi.
Tesla always disputed the claim that Marconi invented radio and he gave a simple reason for this position. It was that radio is not an invention: 'It was evident to me [in ] that wireless transmission of energy, if it could ever be accomplished, is not an invention; it is an art. Bell's telephone, Edison's phonograph, or my induction motor were inventions, but the wireless transmission of energy is an art that requires a great many inventions in combination.', (Nikola Tesla, 1916, in Ed. Anderson, Leland, 'Nikola Tesla On His Work With Alternating Currents And Their Application to Wireless Telegraphy, Telephony, and Transmission of Energy, Published 1992). Seen in this context, some believe that it is Tesla's lecture and patent record from 1888 onwards that contains the fundamental information on the '....great many inventions...' that form the basis for modern radio and wireless technology. An ongoing lawsuit regarding this was finally resolved in Tesla's favor in 1944, one year after his death. This decision was based on the facts of the prior work existing before the establishment of Marconi's patent. At the time, the United States Army was involved in a patent infringement lawsuit with Marconi regarding radio, leading some to posit that the government granted Tesla and others the formal recognition in order to nullify any claims Marconi would have to compensation.
On his 50th birthday in 1906, Tesla demonstrated his 200 hp 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.
Prior to the First World War, Tesla looked overseas for investors to fund his research. When the war started, Tesla lost funding he was receiving from his European patents. Wardenclyffe Tower was also demolished towards the end of WWI. Tesla had predicted the relevant issues of the post-World War I environment (a war which theoretically ended) in a printed article (December 20, 1914). Tesla believed that the League of Nations was not a remedy for the times and issues. In 1915, Tesla filed a lawsuit against Marconi attempting, unsuccessfully, to obtain a court injunction against the claims of Marconi. Around 1916, Tesla filed for bankruptcy because he owed so much in back taxes. He was living in poverty.
Tesla started to exhibit pronounced symptoms of obsessive-compulsive disorder in the years following. He became obsessed with the number three. He often felt compelled to walk around a block three times before entering a building, demanded a stack of three folded cloth napkins beside his plate at every meal, etc. The nature of OCD was little understood at the time and no treatments were available, so his symptoms were considered by some to be evidence of partial insanity and this probably hurt what was left of his reputation. This obsessive-compulsive behavior may have originated from the observations over repeated polyphase systems in nature that Tesla researched.
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 $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 the highest engineering award from the IEEE, the Edison Medal. The irony of this honor was probably not lost on Tesla.
Tesla, in August 1917, first established principles regarding frequency and power level for the first primitive radar units in 1934. In the 1917 The Electrical Experimenter, he stated the principles of modern military radar in detail. His study of high-voltage, high-frequency alternating current led to this development. He had formed the concept of using radio waves to detect objects at a distance.
- "For instance, by their [standing electromagnetic waves] use we may produce at will, from a sending station, an electrical effect in any particular region of the globe; [with which] we may determine the relative position or course of a moving object, such as a vessel at sea, the distance traversed by the same, or its speed."
Tesla proposed to use electromagnetic waves to determine the relative position, speed, and course of a moving object and other modern concepts of radar. He had proposed it might help find submarines (which it isn't well-suited for), though it was first applied successfully to find aircraft (after their later proliferation) and surface ships during World War II. Emil Girardeau , working with the first French radar systems, stated he was building radar systems "conceived according to the principles stated by Tesla".
By the twenties, Tesla was reportedly negotiating with the United Kingdom government under Prime Minister Chamberlain about a ray system. Tesla had also stated that efforts had been made to steal the "death ray" (though they had failed). The Chamberlain government was removed, though, before any final negotiations occurred. The incoming Baldwin government found no use for Tesla's suggestions and 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. In 1935, many of Marconi's patents relating to the radio were declared invalid by the United States Court of Claims . The Court of Claims decided that the prior work of Tesla (specifically US645576 and US649621) had anticipated Marconi's later works. Tesla got his last patent in 1928 on January 3, an apparatus for aerial transportation which was the first instance of VTOL aircraft.
When he was eighty-one, Tesla announced he was working on a dynamic theory of gravity but the theory was never published.
Tesla early on stated that '...the relativity theory, by the way, is much older than its present proponents. It was advanced over 200 years ago by my illustrious countryman Boskovic, the great philospher, who, not withstanding other and multifold obligations, wrote a thousand volumes of excellent literature on a vast variety of subjects. Boskovic dealt with relativity, including the so-called time-space continuum...', (1936 unpublished interview, quoted in Anderson, L, ed. Nikola Tesla: Lecture Before the New York Academy of Sciences: The Streams of Lenard and Roentgen and Novel Apparatus for Their Production, April 6, 1897, reconstructed 1994).
Tesla also stated that 'I hold that space cannot be curved, for the simple reason that it can have no properties. It might as well be said that God has properties. He has not, but only attributes and these are of our own making. Of properties we can only speak when dealing with matter filling the space. To say that in the presence of large bodies space becomes curved is equivalent to stating that something can act upon nothing. I, for one, refuse to subscribe to such a view.', (New York Hearald Tribune, September 11, 1932)
Tesla was later sharply critical of Einstein's relativity work, '...[a] magnificent mathematical garb which fascinates, dazzles and makes people blind to the underlying errors. The theory is like a beggar clothed in purple whom ignorant people take for a king...., its exponents are brilliant men but they are metaphysicists rather than scientists...', (New York Times, July 11, 1935, p23, c.8).
Death and afterwards
Tesla died alone in the hotel New Yorker of heart failure, some time between the evening of January 5 and the morning of January 8, 1943. Despite selling his AC electricity patents, he was essentially destitute and died with significant debts.
At the time of his death, Tesla had been working on some form of teleforce weapon, or death ray, the secrets of which he had offered to the United States War Department on the morning of January 5. It appears that his proposed death ray was related to his research into ball lightning and plasma. He was found dead three days later and, after the FBI was contacted by the War Department, his papers were declared to be top secret.
Immediately after Tesla's death became known, the Federal Bureau of Investigation instructed the Office of Alien Property to take possession of his papers and property, despite his US citizenship. All of his personal effects were seized on the advice of presidential advisors. J. Edgar Hoover declared the case "most secret", because of the nature of Tesla's inventions and patents. Tesla's Serbian-Orthodox family and the Yugoslav embassy struggled with American authorities to gain these items after his death due to the potential significance of some of his research. Eventually, his nephew, Sava Kosanovich, got possession of some of his personal effects (which are now housed in the Nikola Tesla Museum in Belgrade, Yugoslavia). Tesla's funeral took place on January 12, 1943 at the Cathedral of Saint John the Divine in Manhattan, New York City.
The Tesla monument at Niagara Falls is located on Goat Island in New York.
The scientific compound derived SI unit measuring magnetic flux density or magnetic induction (commonly known as the magnetic field B), the tesla, was named in his honor (at the Conférence Générale des Poids et Mesures, Paris, 1960).
Life magazine, in a special double issue, listed Tesla in the "100 Most Important People in the Last 1000 Years". He occupied the 57th position, cited as "[one of] the most farsighted inventors of the electrical age". They state his work on the rotating magnetic field and alternating currents helped electrify the world. 
Nikola Tesla was:
In addition, a number of things have been named after him or dedicated to him:
The Tesla Coils of the PC games Red Alert and Red Alert 2 are named in his honor.
- "I have harnessed the cosmic rays and caused them to operate a motive device."
- "Today's scientists have substituted mathematics for experiments, and they wander off through equation after equation, and eventually build a structure which has no relation to reality."
- "So astounding are the facts in this connection, that it would seem as though the Creator, himself had electrically designed this planet..."
- "Tesla has contributed more to electrical science than any man up to his time." —Lord Kelvin
- "Science is but a perversion of itself unless it has as its ultimate goal the betterment of humanity"
- "The world, I think, will wait a long time for Nikola Tesla's equal in achievement and imagination." - Edwin H. Armstrong
- "Tesla is entitled to the enduring gratitude of mankind." —Arthur Compton
- In his speech presenting Tesla with the Edison medal, Vice President Behrend of the Institute of Electrical Engineers eloquently expressed the following: "Were we to seize and eliminate from our industrial world the result of Mr. Tesla's work, the wheels of industry would cease to turn, our electric cars and trains would stop, our towns would be dark and our mills would be idle and dead. His name marks an epoch in the advance of electrical science." Mr. Behrend ended his speech with a paraphrase of Pope's lines on Newton: "Nature and nature's laws lay hid by night. God said: 'Let Tesla be' and all was light."
- Tesla, Nikola, My Inventions, Electrical Experimenter magazine, Feb, June, and Oct, 1919. ISBN 0910077002
- Tesla, Nikola, "The True Wireless". Electrical Experimenter, May 1919. (also at pbs.org)
- Martin, Thomas Commerford, ""The Inventions, Researches, and Writings of Nikola Tesla"", reprinted by Barnes & Noble, 1995 ISBN 0-88029-812-X
- Cheney, Margaret & Uth, Robert, ""Tesla, Master of Lightning"", published by Barnes & Noble, 1999 ISBN 0-7607-1005-8
- Tesla, Nikola, The Strange Life of Nikola Tesla, Unknown date.
- O'Neill, John J., "Prodigal Genius: The Life of Nikola", 1944. ISBN 0913022403 (also at uncletaz.com; [also other items at the site])
- Hoover, John Edgar, et al., FOIA FBI files, 1943.
- Krumme, Katherine, Mark Twain and Nikola Tesla: Thunder and Lightning. December 4, 2000 (PDF)
- Secor, H. Winfield, "Tesla's views on Electricity and the War", Electrical Experimenter , August, 1917.
- Pratt, H., "Nikola Tesla 1856-1943", Proceedings of the IRE, Vol. 44, September, 1956.
- Page, R.M., "The Early History of Radar", Proceedings of the IRE, Volume 50, Number 5, May, 1962, (special 50th Anniversary Issue).
- Tesla, Nikola, "The Problem of Increasing Human Energy", The Century Illustrated Magazine.
- Secor, H.W., "Tesla's Views on Electricity and the War", The Electrical Experimenter, Volume 5, Number 4, August, 1917.
- W.C. Wysock, J.F. Corum, J.M. Hardesty and K.L. Corum, "Who Was The Real Dr. Nikola Tesla? (A Look At His Professional Credentials)". Antenna Measurement Techniques Association, posterpaper, October 22-25, 2001 (PDF)
- Kelley, Thomas Lee, "The enigma of Nikola Tesla". Arizona State University. [Thesis] (PDF)
- Corum, K. L., J. F. Corum, "Nikola Tesla, Lightning Observations, and Stationary Waves". 1994.
- Corum, K. L., J. F. Corum, and A. H. Aidinejad, "Atmospheric Fields, Tesla's Receivers and Regenerative Detectors". 1994.
- "Giant Eye to See Round the World" (DOC)
- Waser, André, "Nikola Tesla’s Radiations and the Cosmic Rays". (PDF)
External links and resources
- Seifer, Marc J., and Michael Behar, Electric Mind, Wired Magazine, October 1998.
Nikola Tesla Museum - Tesla Museum
Tesla Memorial Society of New York, New York state
Wardenclyffe Project, aim to reuse Wardenclyffe. (Shoreham, Long Island, New York)
Pepe's Tesla Pages - Nikola's Page (Hungarian - original images of text)
The problem of Increasing human energy tesla's essay on the working of his mind, and other subjects. Also see picture thinking
PBS: Tesla - Master of Lightning
Wolfram Research's Tesla Entry
- Yale's Scientific Legacy of Nikola Tesla
- Fred Walters' hand-scanned Tesla patents (PDFs)
Erased at the Smithsonian
Nikola Tesla at Everything2.com
Twenty First Century Books: Books and Online Files About Nikola Tesla.
Nikola Tesla Story: Tells more about Tesla and Edison.
- Nikola Tesla in Colorado Springs
- Lomas, Robert, "The essay", Spark of genius. Independent Magazine, August 21, 1999.
- Lomas, Robert, "The Man who Invented the Twentieth Century". Lecture to South Western Branch of Instititute of Physics.
- Germano, Frank, "Dr. Nikola Tesla". Frank.Germano.com.
- Science Friday, "Strange Scientists", August 7, 1998
- Science Friday, "The Science of Radio", October 13, 1995
Tesla's works at Project Gutenberg
Nikola Tesla, Montenegrins, Serbians and Serb patriotism
Nikola Tesla, My Inventions (An Autobiography)
Nikola Tesla's Father - Milutin Tesla
Which Historical Lunatic are You? quiz
- Childres, David H., "The Fantasic inventions of Nikola Tesla". ISBN 0-932813-19-4
- Glenn, Jim, "The Complete Patents of Nikola Tesla", ISBN 1-566192-66-8
- Martin, Thomas C., "The Inventions, Researches, and Writings of Nikola Tesla". ISBN 0-880298-12-X
- Seifer, Marc J., "Wizard, the Life and Times of Nikola Tesla". ISBN 1-559723-29-7 (HC), ISBN 0-806519-60-6 (SC)
- Tesla, Nikola, "Colorado Springs Notes, 1899-1900", ISBN 0-899187-82-X
- Tesla, Nikola, "My Inventions'", ISBN 0-760700-85-0
- Valone, Thomas, "Harnessing the Wheelwork of Nature". ISBN 1-931882-04-5