This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (August 2010)

An alleged flying saucer seen over Passaic, New Jersey in 1952

A flying saucer (also referred to as a flying disc) is a type of flying craft with a disc or saucer-shaped body. Sometimes flying saucers are believed to be of alien origin, in which case they are referred to as unidentified flying objects or (UFO's). These are usually described as silver or metallic, sometimes reported as covered with running lights or surrounded with a glowing light, hovering or moving rapidly, either alone or in tight formations with other similar craft, and exhibiting high maneuverability. Some flying saucers are man-made though, such as the American Chance Vought V-173 / XF5U "Flying Flapjack", the British GFS flying saucer, by the inventor Geoff Hatton, or the British "S.A.U.C.E.R" ("Saucer Aircraft Utilising Coanda Effect Reactions") flying saucer, by the inventor Alf Beharie.

Disc-shaped flying objects have been interpreted as being sporadically recorded since the Middle Ages, the first highly publicized sighting by Kenneth Arnold on June 24, 1947, resulted in the creation of the term by U.S. newspapers. Although Arnold never specifically used the term "flying saucer", he was quoted at the time saying the shape of the objects he saw was like a "saucer", "disc", or "pie-plate", and several years later added he had also said "the objects moved like saucers skipping across the water." (The Arnold article has a selection of newspaper quotes.) Both the terms flying saucer and flying disc were used commonly and interchangeably in the media until the early 1950s.

Arnold's sighting was followed by thousands of similar sightings across the world. Such sightings were once very common, to such an extent that "flying saucer" was a synonym for UFO through the 1960s before it began to fall out of favor. The term is still often used generically for any UFO.

More recently, the flying saucer has been largely supplanted by other alleged UFO-related vehicles, such as the black triangle.^{[citation needed]} The term UFO was, in fact, invented in 1952, to try to reflect the wider diversity of shapes being seen. However, unknown saucer-like objects are still reported, such as in the widely-publicized 2006 sighting over Chicago-O'Hare airport.

Many of the alleged flying saucer photographs of the era are now believed to be hoaxes. The flying saucer is now considered largely an icon of the 1950s and of B-movies in particular, and is a popular subject in comic science fiction.^[1]

Sightings[link]

News notice printed in Nuremberg, describing the 4th April 1561 Nuremberg mass sighting. Discs and spheres were said to emerge from large cylinders. From Wickiana collection in Zurich.

A manuscript illustration of the 10th-century Japanese narrative, The Tale of the Bamboo Cutter, depicts a round flying machine similar to a flying saucer.^[2]

A record of a saucer-shaped object is from 1290 of a silver disc flying over a village in Yorkshire.^[3] Disc-like flying objects were occasionally reported throughout the millennium. For example, in a mass sighting over Nuremberg in 1561, discs and spheres were reported emerging from large cylinders. (woodcut at left) They are also claimed by ufologists to frequently show up in religious artwork.^[4] Artwork of the Annunciation of Mary, for instance, frequently shows a narrow beam of light descending from a saucer-like object. (examples at right and lower left) However, it is usually even ambiguous as to whether the artists were trying to depict something that had been seen or whether there was religious symbolism involved, let alone ufos.^[5]

Possibly the first well-documented instance to specifically compare the objects to saucers, and the first to be widely reported, was the Kenneth Arnold sighting on June 24, 1947, while Arnold was flying near Mount Rainier.^[3] He reported seeing 9 brightly-reflecting vehicles, one shaped like a crescent but the others more disc- or saucer-shaped, flying in an echelon formation, weaving like the tail of a kite, flipping and flashing in the sun, and traveling with a speed of at least 1,200 miles per hour (1,900 km/h).^[6] In addition to the saucer or disc shape (Arnold also used the terms "pie plate" and half-moon shaped), he also later said he described the motion of the craft as "like a saucer if you skip it across water", leading to the term "flying saucer" and also "flying disc" (which were synonymous for a number of years).

14th Century woodcut of the Annunciation of Mary. Annunciation artwork often depicts a narrow beam descending from saucer-like objects.

Immediately following the report, hundreds of sightings of usually saucer-like objects were reported across the United States and also in some other countries. The most widely publicized of these was the sighting by a United Airlines crew on July 4 of nine more disc-like objects pacing their plane over Idaho, not far from Arnold's initial sighting. On July 8, the Army Air Force base at Roswell, New Mexico issued a press release saying that they had recovered a "flying disc" from a nearby ranch (the so-called Roswell UFO incident, which was front-page news until the military issued a retraction saying that it was a weather balloon.

On July 9, the Army Air Force Directorate of Intelligence, assisted by the FBI, began a secret study of the best of the flying saucer reports, including Arnold's and the United Airlines' crew. Three weeks later they issued an intelligence estimate describing the typical characteristics reported (including that they were often reported as disc-like and metallic) and concluded that something was really flying around. A follow-up investigation by the Air Materiel Command at Wright Field, Ohio arrived at the same conclusion. A widespread official government study of the saucers was urged by General Nathan Twining. This led to the formation of Project Sign (also known as Project Saucer) at the end of 1947, the first public Air Force UFO study. This evolved into Project Grudge (1949–1951) and then Project Blue Book (1952–1970).

The term "flying saucer" quickly became deeply ingrained in the English vernacular. A Gallup poll from August 1947 found that 90% had heard about the mysterious flying saucers or flying discs, and a 1950 Gallup poll found that 94% of those polled had heard the term, easily beating out all other mentioned commonly used terms in the news such as "Cold War", "universal military training," and "bookie."

Air Force statistics indicated that the basic saucer-shape continued to be the most commonly reported one through the 1950s and 1960s until Project Blue Book ended in 1970. There have been some claims, still undocumented by scientific study, that reports of saucers began to decline in the 1970s, being supplanted by other craft such as black triangles, cylinders, and amorphous shapes. It has also been asserted that despite the increase in portable cameras, photographs dwindled as Cold War and Space Race interest decreased and a number of notable images were exposed as fakes.^{[citation needed]}

Explanations[link]

In addition to the extraterrestrial hypothesis, a variety of possible explanations for flying saucers have been put forward. One of the most common states that most photos of saucers were hoaxes; cylindrical metal objects such as pie tins, hubcaps and dustbin lids were easy to obtain, and the poor focus seen in UFO images makes the true scale of the object difficult to ascertain.^{[citation needed]} However, some photos and movies were deemed authentic after intensive study. An example was the saucer-like object photographed by farmer Paul Trent near Portland, Oregon in 1950, which passed all tests when studied by the Condon Committee in the 1960s.^[7]

Another theory states that most are natural phenomena such as lenticular clouds and balloons, which appear disc-like in some lighting conditions.^[8]

A third theory puts all saucer sightings down to a form of mass hysteria. Arnold described the craft he saw as saucer-like but not perfectly round (he described them as thin, flat, rounded in front but chopped in back and coming to a point), but the image of the circular saucer was fixed in the public consciousness. The theory posits that as the use of the term flying saucer in popular culture decreased, so too did sightings.^[9]

However, one Air Force commissioned study contradicted some of these contentions. A scientific and statistical analysis of 3200 Air Force cases by the Battelle Memorial Institute from 1952-1954 found that most were indeed due to natural phenomena. But only about 2% were due to hoaxes or psychological effects and only .4% were thought due to clouds. Other very minor contributors to the identifieds were birds, light phenomena such as mirages or searchlights, and various miscellany such as flares or kites. The vast majority of identified objects (about 84%) were explained as balloons, aircraft, or astronomical objects. However, about 22% of all sightings still defied any plausible explanation by the team of scientists. The percent of unidentifieds rose to 33% for the best witnesses and cases. Thus when carefully studied, a very substantial fraction of reports (given the available data) cannot be easily explained away as being caused by mundane phenomena. Other scientific studies have come to similar conclusions. (see Identified flying object for details)

Fata Morgana (mirages) and flying saucers[link]

Fata Morgana of distant islands distorted images beyond recognition

Fata Morgana, a type of mirage, might be responsible for some flying saucers sightings, by displaying objects located below the astronomical horizon hovering in the sky. It might also magnify these objects and make them look absolutely unrecognizable.

Similarly some unidentifieds seen on radar might also be due to Fata Morgana-type atmospheric phenomena, though more technically known as "anomalous propagation" and more commonly as "radar ghosts". Official UFO investigations in France indicates:^[10]

As is well known, atmospheric ducting is the explanation for certain optical mirages, and in particular the arctic illusion called "fata morgana" where distant ocean or surface ice, which is essentially flat, appears to the viewer in the form of vertical columns and spires, or "castles in the air."
People often assume that mirages occur only rarely. This may be true of optical mirages, but conditions for radar mirages are more common, due to the role played by water vapor which strongly affects the atmospheric refractivity in relation to radio waves. Since clouds are closely associated with high levels of water vapor, optical mirages due to water vapor are often rendered undetectable by the accompanying opaque cloud. On the other hand, radar propagation is essentially unaffected by the water droplets of the cloud so that changes in water vapor content with altitude are very effective in producing atmospheric ducting and radar mirages.

Fata Morgana was named as a hypothesis for the mysterious Australian phenomenon Min Min light^[11]

Earth-based examples[link]

The Avrocar, a one-man flying saucer style aircraft

The first^{[citation needed]} documented patent for a lenticular flying machine was submitted by Romanian inventor Henri Coanda. He made a functional small scale model which was flown in 1932 and a patent was granted in 1935 ^[12] At a Symposionum organized by the Romanian Academy in 1967 Coanda said:

"These airplanes we have today are no more than a perfection of a toy made of paper children use to play with. My opinion is we should search for a completely different flying machine, based on other flying principles. I consider the aircraft of the future, that which will take off vertically, fly as usual and land vertically. This flying machine should have no parts in movement. The idea came from the huge power of the cyclons" [sic]^[13]

Other attempts have been made, with limited success, to produce manned vehicles based on the flying saucer design. While some, such as the Avrocar and M200G Volantor have been produced in limited numbers, most fail to leave the drawing board. The Avrocar, with vertical takeoff and landing, was originally intended to replace both the Jeep and the helicopter in combat situations, but proved to be inadequate for both. In spite of a powerful turbojet, it could not rise more than four or five feet off the ground, i.e., out of ground effect.^[14] Thus, the Avrocar could be seen as a prototype for the early generations of hovercraft, lacking only a 'skirt' to make it a truly effective example of the type. Unmanned saucers have had more success; the Sikorsky Cypher is a saucer-like UAV which uses the disc-shaped shroud to protect rotor blades.

The British Rail flying saucer, a proposed saucer-like spacecraft

Some more advanced flying saucers capable of spaceflight have been proposed, often as black projects by aeronautics companies. The Lenticular Reentry Vehicle was a secret project run by Convair for a saucer device which could carry both astronauts and nuclear weapons into orbit; the nuclear powered system was planned in depth, but is not believed to have ever flown. More exotically, British Rail worked on plans for the British Rail "Space Vehicle" a proposed, saucer-shaped craft based on so far undiscovered technologies such as nuclear fusion and superconductivity, which was supposed to have been able to transport multiple passenger between planets, but never went beyond the patent stage.^[1]

There is at least one design that received a US patent in 2005: U.S. Patent 6,960,975 It claims to be "propelled by the pressure of inflationary vacuum state".

Additionally, a professor at the University of Florida has begun work on a Wingless Electromagnetic Air Vehicle (WEAV) for NASA which has received public interest because of its coincidental resemblance to a flying saucer.^{[15][16][17][18][clarification needed]}

Military uses[link]

In the last decade, plasma induction technologies have led to the advance of propulsion and energy systems, operators such as the USAF and NASA have taken an interest in utilizing this tech for the purpose of building flying saucers.^[19]

In popular culture[link]

Surprisingly, long before the Kenneth Arnold sighting of 1947 and the adoption of the term "flying saucer" by the press, spacecraft of human or alien origin were often illustrated as classic flying saucers in the popular press, dating back to at least 1911.^[20]

A small flying saucer leaves its larger mothership in Plan 9 from Outer Space.

After 1947, the flying saucer quickly became a stereotypical symbol of both extraterrestrials and science fiction, and features in many films of mid-20th century science fiction, including The Atomic Submarine, The Day the Earth Stood Still, Plan 9 from Outer Space, Ray Harryhausen's stop-motion epic, Earth vs. the Flying Saucers, as well as the television series The Invaders. As the flying saucer was surpassed by other designs and concepts, it fell out of favor with straight science-fiction movie makers, but continued to be used ironically in comedy movies, especially in reference to the low-budget B movies which often featured saucer-shaped alien craft.

MGM, however, gave it's 1956 Forbidden Planet A-film high production values in the United Planet's Cruiser C-57D, presenting a plausable human exploration, faster-than-light starship of the 23rd century.

The saucer design did, however, make a temporary comeback on the television series Babylon 5 as the standard ship design used by a race called the Vree, described in the series as one of Earth's long-standing allies who had visited Earth in the distant past, and who bore a strong resemblance to the "Greys". Aliens in the film Independence Day attacked humanity in giant city sized saucer shaped space ships.

The sleek, silver flying saucer in particular is seen as a symbol of 1950s culture; the motif is common in Googie architecture and in Atomic Age décor.^[21] The image is often invoked retrofuturistically to produce a nostalgic feel in period works, especially in comic science fiction; both Mars Attacks!^[22] and Destroy All Humans!^[23] draw on the flying saucer as part of the larger satire of 1950s B movie tropes.

The Twilight Zone episodes "The Monsters Are Due on Maple Street", "Third from the Sun", "Death Ship", "To Serve Man", "The Invaders" and "On Thursday We Leave for Home" all use Forbidden Planet's iconic saucer.

UFO religions[link]

Raëlism is a UFO religion founded by a purported contactee named Claude Vorilhon. They believe that Elohim (plural) are advanced extraterrestrials who created humanity and life on Earth whose previous and ancient contacts have provided the founding for many major religions in existence today.

In esoteric Nazism, it is believed that there were Nazi UFOs with underground bases in New Swabia, Antarctica, South America, and/or America, and that these survived after World War Two.^[24]

References[link]

External links[link]

• FBI Special Agent Guy Hottel's memo

v t e UFOs and ufology Index of ufology articles Notable incidents List of aircraft-UFO incidents List of UFO sightings in outer space Aurora (1897) Roswell (1947) Washington (1952) Tehran (1976) Rendlesham Forest (1980) Japan Air Lines (1986) Belgian UFO wave (1990) Phoenix Lights (1997) 21st century Mexico (2004) Tinley Park Lights (2004-2006) O'Hare Airport (2006) Alderney (2007) Stephenville (2008) Turkey (2008) Wales (2008) Norway (2009) Harbour Mille (2010) Vancouver, Washington (2011) Sightings by country Argentina Australia Belarus Belgium Brazil Canada China France Indonesia Iran Iraq Italy Mexico New Zealand Norway Philippines Portugal Russia South Africa Spain (Canary Islands) Sweden United Kingdom United States Hypothesis and studies UFO hypotheses (Extraterrestrial hypothesis) Project Blue Book Condon Report COMETA Report List of notable studies in ufology Identification studies of UFOs Types Black triangle Fastwalkers Flying saucer Foo fighter Ghost rockets Green fireballs Mystery airship UFO conspiracy theory Majestic 12 Area 51 Bob Lazar Men in Black Project Serpo Disclosure Project Culture UFO Culture UFO religion List of UFO religions UFOs in fiction Involvement Government responses Organizations Ufologists Abduction Contactee Topics Declassification of UFO documents Skeptics List of skeptics and skeptical organizations Committee for Skeptical Inquiry

Nikola Tesla
Tesla, aged 37, 1893, photo by Napoleon Sarony
Born	(1856-07-10)10 July 1856 Smiljan, Austrian Empire (Croatian Military Frontier)
Died	7 January 1943(1943-01-07) (aged 86) Manhattan, New York, USA
Residence	Manhattan, New York, USA Karlovac, Croatia Budapest, Hungary
Citizenship	Austrian Empire (10 July 1856 – 29 October 1918)[citation needed] United States (30 July 1891 – 7 January 1943)
Fields	Electrical engineering Mechanical engineering
Institutions	Edison Machine Works Tesla Electric Light & Manufacturing Westinghouse Electric & Manufacturing Co.
Alma mater	Graz University of Technology Charles University in Prague
Known for	Alternating current Bifilar coil Death ray Electrogravitics Induction motor Particle beam weapon Rotating magnetic field Teleforce Tesla coil Tesla electric car Tesla principle Tesla turbine Tesla's Egg of Columbus Tesla's oscillator Telegeodynamics Terrestrial stationary waves Wireless technology
Influences	Ernst Mach
Influenced	Gano Dunn
Notable awards	Order of St. Sava (1892) Elliott Cresson Medal (1894) Edison Medal (1916) John Scott Medal (1934)
Signature

Nikola Tesla (Serbian Cyrillic: Никола Тесла; 10 July 1856 – 7 January 1943) was a Serbian-American inventor, physicist, mechanical engineer, electrical engineer, and futurist. He was an important contributor to the use of commercial electricity, and is best known for developing the modern alternating current (AC) electrical supply system. His many revolutionary developments in the field of electromagnetism in the late 19th and early 20th centuries were based on the theories of electromagnetic technology discovered by Michael Faraday. Tesla's patents and theoretical work also formed the basis of wireless communication and the radio.

Born in the village of Smiljan (now part of Gospić, present day Croatia), Tesla was a subject of the Austrian Empire by birth and later became an American citizen.^[1] Because of his 1894 demonstration of short range wireless communication through radio^[2] and as the eventual victor in the "War of Currents", he was widely respected as one of the greatest electrical engineers who worked in America.^[3] He pioneered modern electrical engineering and many of his discoveries were of groundbreaking importance. In the United States during this time, Tesla's fame rivaled that of any other inventor or scientist in history or popular culture.^[4] Tesla demonstrated wireless energy transfer to power electronic devices in 1891,^[5] and aspired to intercontinental wireless transmission of industrial power in his unfinished Wardenclyffe Tower project.

Tesla became reclusive towards the end of his life, living alone in a New York City hotel room and only appearing occasionally to make unusual statements to the press.^[6][7] Because of his pronouncements and the nature of his work over the years Tesla gained a reputation in popular culture as the archetypal "mad scientist".^[8][9] He died with little money to his name.^[10]

Tesla's work fell into relative obscurity after his death but since the 1990s his reputation has experienced a popular culture comeback.^[11] In 2005 he was listed amongst the top 100 nominees in the TV show "The Greatest American", an open access popularity poll conducted by AOL and The Discovery Channel.

The SI unit measuring magnetic field B (also referred to as the magnetic flux density and magnetic induction), the tesla, was named in his honor (at the CGPM, Paris, 1960).

Early years[link]

Nikola Tesla was born to Serbian parents in the village of Smiljan, Austrian Empire near the town of Gospić, in the territory of modern-day Croatia. His baptismal certificate reports that he was born on 28 June (N.S. 10 July) 1856 to father Milutin Tesla, a priest in the Serbian Orthodox Church.^[12] His mother was Đuka Tesla, née Mandić, whose father was also a Serbian Orthodox priest.^[13] She was talented in making home craft tools and memorized many Serbian epic poems, but never learned to read.^[14] Tesla's biographer John O'Neill relates that "the Tesla and Mandić families originally came from the western part of Serbia near Montenegro."^[15]

Nikola was the fourth of five children, having one older brother (Danilo, who was killed in a horse-riding accident when Nikola was five) and three sisters (Milka, Angelina and Marica).^[16] His family moved to Gospić in 1862. Tesla attended school at Higher Real Gymnasium in Karlovac.^[17] He finished a four-year term in the span of three years.^[18]

Nikola Tesla's house (parish hall) in village Smiljan where he was born and the church where his father served (present day Croatia).

Tesla went on to study electrical engineering at the Austrian Polytechnic in Graz (1875). While there, he studied the uses of alternating current. Some sources say he received Baccalaureate degrees from the university at Graz.^[19][20][21] However, the university says that he did not receive a degree and did not continue beyond the first semester of his third year, during which he stopped attending lectures.^{[22][23][24][25]} In December 1878, Tesla left Graz and broke all relations with his family. His friends thought that he had drowned in the Mur River. He went to Marburg, (today's Maribor, in Slovenia), where he was first employed as an assistant engineer for a year. He suffered a nervous breakdown during this time. 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.^[26]

Nikola Tesla c. 1879 at age 23, and his passport from 1883

Tesla engaged in reading many works, memorizing complete books, supposedly having a photographic memory.^[27] 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 visions. Much of the time the visions were linked to a word or idea he might have come across, at other times they would provide the solution to a particular problem he had been encountering; just by hearing the name of an item, he would be able to envision it in realistic detail. Modern-day synesthetes report similar symptoms. Tesla would visualize an invention in his mind with extreme precision, including all dimensions, before moving to the construction stage; a technique sometimes known as picture thinking. He typically did not make drawings by hand, instead just conceiving all ideas with his mind. Tesla also often had flashbacks to events that had happened previously in his life; these began during his childhood.^[27]

In 1880, he moved to Budapest to work under Tivadar Puskás in a telegraph company,^[28] the National Telephone Company. There, he met Nebojša Petrović, a young, Serbian inventor who lived in 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.^[29]

Drawing from U.S. Patent 381968, illustrating principle of Tesla's alternating current motor

Working for Edison in France and the U.S[link]

In 1882 he moved to Paris, to work as an engineer for the Continental Edison Company, designing improvements to electric equipment brought overseas from Edison's ideas. According to Tesla's autobiography, in the same year he conceived of his induction motor and began developing various devices that use rotating magnetic fields for which he received patents in 1888. The paternity of the invention remains controversial since a prototype induction motor was demonstrated in Europe in 1885 by Galileo Ferraris.^{[30][31][32][33]} Ferraris published his findings in 1888.

On 6 June 1884, Tesla first arrived in the United States, in New York City^[34] with little besides a letter of recommendation from Charles Batchelor, a former employer. In the letter of recommendation to Thomas Edison, it is claimed that Batchelor wrote, 'I know two great men and you are one of them; the other is this young man', but the exact contents of the letter is disputed in McNichol's book. Edison hired Tesla to work for his Edison Machine Works. Tesla's work for Edison began with simple electrical engineering and quickly progressed to solving some of the company's most difficult problems. Tesla was even offered the task of completely redesigning the Edison company's direct current generators.^[35]

In 1885 Tesla claimed he could redesign Edison's inefficient motor and generators, making an improvement in both service and economy. According to Tesla, Edison remarked "There's fifty thousand dollars in it for you - if you can do it".^[36] This has been noted as an odd statement from an Edison whose company was stingy with pay and did not have that sort of cash on hand.^[37] After months of work when Tesla finished the task and inquired about payment Edison claimed he was only joking replying, "Tesla, you don't understand our American humor".^[38][39] Edison offered a $10 a week raise over Tesla's US$18 per week salary, but Tesla refused it and immediately resigned.^[36]

Tesla, in need of work, eventually found himself digging ditches for a short period of time for the Edison company. He used this time to focus on his AC polyphase system.^[40]

Middle years[link]

Wireless transmission of power and energy demonstration during his high frequency and potential lecture of 1891 Electromechanical devices and principles developed by Nikola Tesla: Various devices that use rotating magnetic fields (1882) The Induction motor, rotary transformers, and "high" frequency alternators The Tesla coil,[41] his magnifying transmitter, and other means for increasing the intensity of electrical oscillations (including condenser discharge transformations and the Tesla oscillators[42][43]) Alternating current long-distance electrical transmission system[44] (1888) and other methods and devices for power transmission Systems for wireless communication (prior art for the invention of radio) and radio frequency oscillators[45] Robotics and the electronic logic gate[46] Electrotherapy Tesla currents[47][48][49] Wireless transfer of electricity and the Tesla effect[50][51] Tesla impedance phenonomena[52] Tesla electro-static field Tesla principle Bifilar coil Telegeodynamics Tesla insulation Tesla impulses[53] Tesla frequencies[41] Tesla discharge[41] Forms of commutators and methods of regulating third brushes Tesla turbines (e.g., bladeless turbines) for water, steam and gas and the Tesla pumps Tesla igniter Corona discharge ozone generator Tesla compressor X-rays Tubes using the Bremsstrahlung process Devices for ionized gases and "Hot Saint Elmo's Fire".[54] Devices for high field emission Devices for charged particle beams Phantom streaming devices[55] Arc light systems Methods for providing extremely low level of resistance to the passage of electric current (predecessor to superconductivity) Voltage multiplication circuitry Devices for high voltage discharges Devices for lightning protection VTOL aircraft Dynamic theory of gravity Concepts for electric vehicles Polyphase systems

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 laborer from 1886 to 1887 to feed himself and raise capital for his next project. In 1887, he constructed a 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 long distances.

In April 1887, Tesla began investigating what would later be called X-rays using his own single terminal vacuum tubes (similar to his patent #514,170). This device differed from other early X-ray tubes in that it had no target electrode. The modern term for the phenomenon produced by this device is bremsstrahlung (or braking radiation). It is now known that this device operated by emitting electrons from the single electrode through a combination of field electron emission and thermionic emission. Once liberated, electrons are strongly repelled by the high electric field near the electrode during negative voltage peaks from the oscillating HV output of the Tesla Coil, generating X rays as they collide with the glass envelope. He also used Geissler tubes. By 1892, Tesla became aware of the skin damage that Wilhelm Röntgen later identified as an effect of X rays.

In the early research, Tesla devised several experimental setups to produce X-rays. Tesla held that, with his circuits, the "instrument will [... enable one to] generate Roentgen rays of much greater power than obtainable with ordinary apparatus".^[56]

He also commented on the hazards of working with his circuit and single-node X-ray-producing devices. Of his many notes in the early investigation of this phenomenon, he attributed the skin damage to various causes. He believed early on that damage to the skin was not caused by the Roentgen rays, but the ozone generated in contact with the skin, and to a lesser extent, nitrous acid. Tesla incorrectly held that x-rays were longitudinal waves, such as those produced in waves in plasma. There are known examples of this and these plasma waves can occur in the situation of force-free magnetic fields.^[57][58] His hypotheses and experiments were confirmed by others.^[59]

Tesla continued research in the field. He performed several experiments prior to Roentgen's discovery (including photographing the bones of his hand; later, he sent these images to Roentgen) but did not make his findings widely known; much of his research was lost in the 5th Avenue laboratory fire of March 1895.

Tesla demonstrated wireless energy transmission as early as 1891. The Tesla effect is a 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).^[50][60]

American citizenship[link]

Tesla demonstrated a radio-controlled boat on 1898 U.S. Patent 613,809, named Method of an Apparatus for Controlling Mechanism of Moving Vehicle or Vehicles

On 30 July 1891, at the age of 35, he became a naturalized citizen of the United States. Tesla established his South Fifth Avenue laboratory in New York in the same year. Later, Tesla established his Houston Street laboratory in New York at 46 E. Houston Street. He lit electric lamps wirelessly at both of the New York locations, providing evidence for the potential of wireless power transmission.^[61]

Soon thereafter, in 1892,^[62] Tesla was awakened from a dream in which his mother had died.^[63] He returned to Europe for her funeral. After her death, Tesla fell ill. He spent two to three weeks recuperating in Gospić and the village of Tomingaj near Gračac, his mother's birthplace.

Some of Tesla's closest friends were artists. He befriended Century Magazine editor Robert Underwood Johnson, who adapted several Serbian poems of Jovan Jovanović Zmaj (which Tesla translated). Also during this time, Tesla was influenced by the Vedic philosophy (i.e., Hinduism) teachings of the Swami Vivekananda; so much so that, after his exposure to Hindu-Vedic thought, Tesla started using Sanskrit words to name some of his fundamental concepts regarding matter and energy.^[64]

Nikola Tesla's AC dynamo-electric machine (Electric generator) used to generate AC which is used to transport electricity across great distances. It is contained in U.S. Patent 390,721.

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. Tesla served, from 1892 to 1894, as the vice president of the American Institute of Electrical Engineers, the forerunner (along with the Institute of Radio Engineers) of the modern-day IEEE. 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, invented a cordless gas discharge lamp, and transmitted electromagnetic energy without wires, building the first radio transmitter.^{[citation needed]} In St. Louis, Missouri, Tesla made a demonstration related to radio communication in 1893.^{[citation needed]} Addressing the Franklin Institute in Philadelphia, Pennsylvania and the National Electric Light Association, he described and demonstrated in detail its principles. Tesla's demonstrations were written about widely through various media outlets. Tesla also investigated harvesting energy that is present throughout space. He believed that it was merely a question of time when men would succeed in attaching their machinery to the very wheelwork of nature, stating: "Ere many generations pass, our machinery will be driven by a power obtainable at any point of the universe."^[65]

At the 1893 World's Fair, the World's Columbian Exposition in Chicago, 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. On display were fluorescent lamps developed by Westinghouse^[66] and single node bulbs. An observer noted:

Within the room was suspended two hard-rubber plates covered with tin foil. These were about fifteen feet apart, and served as terminals of the wires leading from the transformers. When the current was turned on, the lamps or tubes, which had no wires connected to them, but lay on a table between the suspended plates, or which might be held in the hand in almost any part of the room, were made luminous. These were the same experiments and the same apparatus shown by Tesla in London about two years previous, "where they produced so much wonder and astonishment".^[67]

Tesla also 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 demonstration of the device he constructed known as the "Egg of Columbus".

The Tesla generator was developed by Tesla in 1895, in conjunction with his developments concerning the liquefaction of air. Tesla knew from Lord Kelvin's discoveries that more heat is absorbed by liquefied air when it is re-gasified and used to drive something than is required by theory; in other words, that the liquefaction process is somewhat anomalous or 'over unity'.^[68] Just before Tesla's completion of his work and the filing of a patent application, Tesla's laboratory burned down, destroying all his equipment, models and inventions. Immediately after the fire, Carl von Linde, in Germany, filed a patent application for the same process.^[69]

A "world system" for "the transmission of electrical energy without wires" that depends upon the electrical conductivity of the earth was proposed, in which transmission in various natural media 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.^{[citation needed]} The same concept is used in virtual lightning rods and the electrolaser electroshock weapon,^[70] and has been proposed for disabling vehicles.

Also in the late 1880s, Tesla and Thomas Edison became adversaries in part because of Edison's promotion of direct current (DC) for electric power distribution over the more efficient alternating current advocated by Tesla and Westinghouse. Until the development of the induction motor, AC's advantages for long distance high voltage transmission were counterbalanced by the inability to operate motors on AC.^{[citation needed]} As a result of the "War of Currents", Edison and Westinghouse went nearly bankrupt, so in 1897, Tesla released Westinghouse from contract, providing Westinghouse a break from Tesla's patent royalties. Also in 1897, Tesla researched radiation, which led to setting up the basic formulation of cosmic rays.^[71]

In 1897, at age 41, Tesla filed the first radio patent (U.S. Patent 645,576). A year later, he demonstrated a radio-controlled boat to the US military, believing that the military would want things such as radio-controlled torpedoes. Tesla claimed to have developed the "Art of Telautomatics", a form of robotics, as well as the technology of remote control.^[72] In 1898, he demonstrated a radio-controlled boat to the public during an electrical exhibition at Madison Square Garden. Tesla called his boat a "teleautomaton".^[73] In the same year, Tesla devised an "electric igniter" or spark plug for Internal combustion gasoline engines. He gained U.S. Patent 609,250, "Electrical Igniter for Gas Engines", on this mechanical ignition system. Tesla lived in the former Gerlach Hotel, renamed The Radio Wave building, at 49 W 27th St. (between Broadway and Sixth Avenue), Lower Manhattan, before the end of the century where he conducted the radio wave experiments. A commemorative plaque was placed on the building in 1977 to honor his work. Remote radio control remained a novelty until World War I and afterward, when a number of countries used it in military programs.

Colorado Springs[link]

Publicity picture of Nikola Tesla sitting in his laboratory in Colorado Springs with his "Magnifying transmitter" generating millions of volts. The arcs are about 7 meters (23 ft) long. (Tesla's notes identify this as a multiple exposure photograph.)

An experiment in Colorado Springs. This bank of lights is receiving power by means of electrodynamic induction from a nearby transmitter

A Colorado Springs experiment: here a grounded tuned coil in resonance with a distant transmitter illuminates a light near the bottom of the picture.

In 1899, Tesla decided to move and began research in Colorado Springs, Colorado in a lab located near Foote Ave. and Kiowa St.,^[74] where he would have room for his high-voltage, high-frequency experiments. Upon his arrival he told reporters that he was conducting wireless telegraphy experiments transmitting signals from Pikes Peak to Paris. Tesla's diary contains explanations of his experiments concerning the ionosphere and the ground's telluric currents via transverse waves and longitudinal waves.^[75] At his lab, Tesla proved that the earth was a conductor, and he produced artificial lightning (with discharges consisting of millions of volts, and up to 135 feet long).^[76] Tesla also investigated atmospheric electricity, observing lightning signals via his receivers. Reproductions of Tesla's receivers and coherer circuits show an unpredicted level of complexity (e.g., distributed high-Q helical resonators, radio frequency feedback, crude heterodyne effects, and regeneration techniques).^[77] Tesla stated that he observed stationary waves during this time.^[78]

Tesla researched ways to transmit power and energy wirelessly over long distances (via transverse waves, to a lesser extent, and, more readily, longitudinal waves). He transmitted extremely low frequencies through the ground as well as between the Earth's surface and the Kennelly–Heaviside layer. He received patents on wireless transceivers that developed standing waves by this method. In his experiments, he made mathematical calculations and computations based on his experiments and discovered that the resonant frequency of the Earth was approximately 8 hertz (Hz). In the 1950s, researchers confirmed that the resonant frequency of the Earth's ionospheric cavity was in this range (later named the Schumann resonance).

In Colorado Springs Tesla carried out various long distance wireless transmission-reception experiments. Tesla effect is the application of a type of electrical conduction (that is, the movement of energy through space and matter; not just the production of voltage across a conductor). Through longitudinal waves,^{[citation needed]} Tesla transferred energy to receiving devices. He sent electrostatic forces through natural media across a conductor situated in the changing magnetic flux and transferred electrical energy to a wireless receiver.

In the Colorado Springs lab, Tesla observed unusual signals that he later thought may have been evidence of extraterrestrial radio wave communications coming from Venus or Mars.^[79] He noticed repetitive signals from his receiver which were substantially different from the signals he had noted from storms and earth noise. Specifically, he later recalled that the signals appeared in groups of one, two, three, and four clicks together. Tesla had mentioned that he thought his inventions could be used to talk with other planets. There have even been claims that he invented a "Teslascope" for just such a purpose. It is debatable what type of signals Tesla received or whether he picked up anything at all. Research has suggested that Tesla may have had a misunderstanding of the new technology he was working with,^[80] or that the signals Tesla observed may have been non-terrestrial natural radio source such as the Jovian plasma torus signals.^[81]

Tesla left Colorado Springs on 7 January 1900. The lab was torn down ca. 1905 and its contents sold to pay debts. The Colorado experiments prepared Tesla for the establishment of the trans-Atlantic wireless telecommunications facility known as Wardenclyffe near Shoreham, Long Island.

Wardenclyffe years[link]

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 dismantled for scrap during World War I.^[82]

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.

Nobel prize and Tesla[link]

Since the Nobel Prize in Physics was awarded to Guglielmo Marconi for radio in 1909, Thomas Edison and Tesla were mentioned in a press dispatch as potential laureates to share the Nobel Prize of 1915, leading to one of several Nobel Prize controversies. Some sources have claimed that because of their animosity toward each other neither was given the award, despite their scientific contributions; that each sought to minimize the other's achievements and right to win the award; that both refused ever to accept the award if the other received it first; and that both rejected any possibility of sharing it.^[14][83]

In the years after these rumors, neither Tesla nor Edison won the Prize (although Edison did receive one of 38 possible bids in 1915, and Tesla did receive one bid out of 38 in 1937).^[84] Earlier, Tesla alone was rumored to have been nominated for the Nobel Prize of 1912. The rumored nomination was primarily for his experiments with tuned circuits using high-voltage high-frequency resonant transformers.

Later years[link]

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.

The Wardenclyffe Tower facility

Before World War I (1914-1918), 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. After the war ended, Tesla made predictions regarding the relevant issues of the post-World War I environment, in a printed article (20 December 1914). Tesla believed that the League of Nations was not a remedy for the times and issues. 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 undoubtedly hurt what was left of his reputation.

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.^[85]

In 1934, Émile Girardeau, working with the first French radar systems, stated he was building them "according to the principles stated by Tesla". By the 1920s, Tesla was reportedly negotiating with the United Kingdom government about a ray system.^{[citation needed]} Tesla had also stated that efforts had been made to steal the so called "death ray".^{[citation needed]} It is suggested that the removal of the Chamberlain government ended negotiations.^{[citation needed]}

On Tesla's 75th 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 Janković 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.

Tesla's famous telegram exchange with Vladko Maček is preserved in the Technical Museum in Zagreb, Croatia

In 1936, replying to a birthday telegram from Vladko Maček, Tesla said he was "equally proud" of his "Serbian origin and Croatian homeland",^[86] a phrase often paraphrased in conciliatory context at modern-day joint Croatian-Serbian Tesla celebrations.^[87] In addition, in the same telegram, Tesla wrote "Long live all Yugoslavs."^{[citation needed]} When others tried to co-opt him into ethnic and other conflicts in Yugoslavia, Tesla once replied: "If your hate could be turned into electricity, it would light up the whole world."^[86]

Field theories[link]

When he was 81, Tesla stated he had completed a "dynamic theory of gravity".^[88] He stated that it was "worked out in all details" and that he hoped to soon give it to the world.^[89] The theory was never published.

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 use. Reminiscent of Mach's principle, Tesla stated in 1925 that:

Nikola Tesla, with Ruđer Bošković's book Theoria Philosophiae Naturalis, sits in front of the spiral coil of his high-frequency transformer at East Houston Street, New York.

There is no thing endowed with life—from man, who is enslaving the elements, to the nimblest creature—in all this world that does not sway in its turn. Whenever action is born from force, though it be infinitesimal, the cosmic balance is upset and the universal motion results.

Tesla was critical of Einstein's relativity work, calling it:

...[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 ...^[90]

Tesla also argued:

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.^[91]

Tesla also believed that much of Albert Einstein's relativity theory had already been proposed by Ruđer Bošković, stating in an unpublished interview:

...the relativity theory, by the way, is much older than its present proponents. It was advanced over 200 years ago by my illustrious countryman Ruđer Bošković, the great philosopher, who, notwithstanding other and multifold obligations, wrote a thousand volumes of excellent literature on a vast variety of subjects. Bošković dealt with relativity, including the so-called time-space continuum ...'.^[92]

Directed-energy weapon[link]

Later in life, Tesla made remarkable claims concerning a "teleforce" weapon.^[93] The press called it a "peace ray" or death ray.^[94][95] In total, the components and methods included:^{[96][97][dubious – discuss]}

• 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 from the early 1900s until his death.^{[dubious – discuss]} In 1937, Tesla wrote a treatise entitled "The Art of Projecting Concentrated Non-dispersive Energy through the Natural Media", which concerned charged particle beams.^{[98][dubious – discuss]} 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 describing the particle beam is currently in the Nikola Tesla Museum archive in Belgrade. It describes an open-ended vacuum tube with a gas jet seal that allows 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).^{[98][dubious – discuss]}

His records indicate that the device is 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 gives 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.^[99]

Tesla described the weapon as being able to be used against ground based infantry or for antiaircraft purposes.^[100] Tesla tried to interest the US War Department in the device.^[101] He also offered this invention to European countries.^[102] None of the governments purchased a contract to build the device. He was unable to act on his plans.^[103]

Theoretical inventions[link]

Another of Tesla's theorized inventions is commonly referred to as Tesla's Flying Machine, which appears to resemble an ion-propelled aircraft.^[104] 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.^[105]

Personal life[link]

Nikola Tesla's father Milutin, Serbian Orthodox priest in the village of Smiljan.

Possessing an eidetic memory, Nikola Tesla was a polyglot, and along with his native tongue he also spoke Czech, English, French, German, Hungarian, Italian, and Latin.^[106]

During his second year of study at Graumltz, Tesla developed a passion for (and became very proficient at) billiards, chess and card-playing, sometimes spending more than 48 hours in a stretch at a gaming table.^[107][108] Tesla by nature required little sleep, claiming to never sleep more than two hours.^[109] On one occasion at his laboratory Tesla worked for a period of 84 hours without sleep or rest.^[110]

Tesla may have suffered from obsessive-compulsive disorder, and had many unusual quirks and phobias. He did things in threes, and was adamant about staying in a hotel room with a number divisible by three. Tesla was physically revolted by jewelry, notably pearl earrings.^[111] He was fastidious about cleanliness and hygiene, and was by all accounts mysophobic.

Tesla was obsessed with pigeons, ordering special seeds for the pigeons he fed in Central Park and even bringing injured ones into his hotel room to nurse them back to health. Tesla was an animal-lover, often reflecting contentedly about a childhood cat, "The Magnificent Mačak." Tesla never married. He was celibate and claimed that his chastity was very helpful to his scientific abilities.^[27] Nonetheless there have been numerous accounts of women vying for Tesla's affection, even some madly in love with him. Tesla, though polite, behaved rather ambivalently to these women in the romantic sense.

Tesla was prone to alienating himself and was generally soft-spoken. However, when he did engage in a social life, many people spoke very positively and admiringly of him. Robert Underwood Johnson described him as attaining a "distinguished sweetness, sincerity, modesty, refinement, generosity, and force." His loyal secretary, Dorothy Skerrit, wrote: "his genial smile and nobility of bearing always denoted the gentlemanly characteristics that were so ingrained in his soul." Tesla's friend Hawthorne wrote that "seldom did one meet a scientist or engineer who was also a poet, a philosopher, an appreciator of fine music, a linguist, and a connoisseur of food and drink."

Nevertheless, Tesla could be harsh at times; he openly expressed his disgust for overweight people, once firing a secretary because of her weight.^[112] He was quick to criticize others' clothing as well, on several occasions directing a subordinate to go home and change her dress.^[27]

Tesla was widely known for his great showmanship, presenting his innovations and demonstrations to the public as an artform, almost like a magician. This seems to conflict with his observed reclusiveness; Tesla was a complicated figure. He refused to hold conventions without his Tesla coil blasting electricity throughout the room, despite the audience often being terrified, though he assured them everything was perfectly safe.

Mark Twain in Tesla's lab, early 1894

In middle age, Tesla became close friends with Mark Twain. They spent a lot of time together in his lab and elsewhere.

Tesla remained bitter in the aftermath of his dispute with Edison. The day after Edison died the New York Times contained extensive coverage of Edison's life, with the only negative opinion coming from Tesla, who was quoted as saying:

He had no hobby, cared for no sort of amusement of any kind and lived in utter disregard of the most elementary rules of hygiene  ... His method was inefficient in the extreme, for an immense ground had to be covered to get anything at all unless blind chance intervened and, at first, I was almost a sorry witness of his doings, knowing that just a little theory and calculation would have saved him 90 percent of the labor. But he had a veritable contempt for book learning and mathematical knowledge, trusting himself entirely to his inventor's instinct and practical American sense.^[113]

Shortly before he died, Edison said that his biggest mistake had been in trying to develop direct current, rather than the superior alternating current system that Tesla had put within his grasp.^[114]

Tesla was good friends with Robert Underwood Johnson. He had amicable relations with Francis Marion Crawford, Stanford White, Fritz Lowenstein, George Scherff, and Kenneth Swezey. He ripped up a Westinghouse contract that would have made him the world's first billionaire, in part because of the implications it would have on his future vision of free power, and in part because it would run Westinghouse out of business, and Tesla had no desire to deal with the creditors.^{[citation needed]}

Tesla lived the last ten years of his life in a two-room suite on the 33rd floor of the Hotel New Yorker, room 3327. There, near the end of his life, Tesla showed signs of encroaching senility, claiming to be visited by a specific white pigeon daily. Several biographers note that Tesla viewed the death of the pigeon as a "final blow" to himself and his work.

Tesla believed that war could not be avoided until the cause for its recurrence was removed, but was opposed to wars in general. However, Tesla came to find exceptions in which he thought certain situations and wars were justifiable.^[115] Tesla sought to reduce distance, such as in communication for better understanding, transportation, and transmission of energy, as a means to ensure friendly international relations.^[116]

Tesla was a life-long bachelor. Like many of his era, he became a proponent of an imposed selective breeding version of eugenics. His opinions stemmed from a belief that humans already interfered with the natural "ruthless workings of nature", rather than conceptions of a "master race" or inherent superiority of one person over another. His advocacy of it was however to push it further. In a 1937 interview, he stated:

... man's new sense of pity began to interfere with the ruthless workings of nature. The only method compatible with our notions of civilization and the race is to prevent the breeding of the unfit by sterilization and the deliberate guidance of the mating instinct .... The trend of opinion among eugenists is that we must make marriage more difficult. Certainly no one who is not a desirable parent should be permitted to produce progeny. A century from now it will no more occur to a normal person to mate with a person eugenically unfit than to marry a habitual criminal.^[117]

In 1926, Tesla commented on the ills of the social subservience of women and the struggle of women toward gender equality, indicated that humanity's future would be run by "Queen Bees". He believed that women would become the dominant sex in the future.^[118]

In his later years Tesla became a vegetarian. In an article for Century Illustrated Magazine he wrote: "It is certainly preferable to raise vegetables, and I think, therefore, that vegetarianism is a commendable departure from the established barbarous habit." Tesla argued that it is wrong to eat uneconomic meat when large numbers of people are starving; he also believed that plant food was "superior to [meat] in regard to both mechanical and mental performance". He also argued that animal slaughter was "wanton and cruel".^[119]

In his final years he suffered from extreme sensitivity to light, sound and other influences.^[120]

Death[link]

This article's references may not meet Wikipedia's guidelines for reliable sources. Please help by checking whether the references meet the criteria for reliable sources. (January 2012)

Gilded urn with Tesla's ashes, in his favorite geometrical object of sphere, Nikola Tesla Museum, Belgrade.

Tesla died on 7 January 1943 at age 86 from heart thrombus, alone in room 3327 of the New Yorker Hotel.^[121] A few days after Tesla's death, the information center of the Yugoslav royal government-in-exile released a statement giving a short review of Tesla's achievements and the schedule for his memorial service and funeral. The speech, written by Louis Adamic, was read in a live broadcast on Radio New York by the mayor of New York City, Fiorello La Guardia, on 10 January 1943. The remains of Nikola Tesla were taken to Campbell cemetery. The protocol anticipated the funeral service would be conducted on 12 January in the Cathedral of Saint John the Divine in Manhattan.^[122] Bishop William T. Manning delivered the introductory and the last prayer in English. The funeral service was conducted in the name of the Serbian Orthodox Church by priest Dusan Sukletovic, the superior of the Church of St. Sava of the New York parish. The bereaved family members present at the funeral were Sava Kosanovic and Nikola Trbojevic. A state funeral was attended by 2000 people. Tesla's casket was draped with U. S. and Yugoslav flags. The pallbearers were Nobel prize winners. Telegrams of condolence were received from many notables including the First Lady of the United States, Mrs Eleanor Roosevelt and Vice-President Henry A. Wallace. Tesla's body was cremated and his ashes taken to Belgrade, Serbia, then-Yugoslavia in 1957. The urn containing his ashes was placed in the Nikola Tesla Museum in Belgrade. Despite having sold his AC electricity patents, Tesla died with significant debts. Later that year the US Supreme Court upheld Tesla's patent number 645576 in a ruling that served as the basis for patented radio technology in the United States.^[123]

Soon after his death Tesla's safe was opened by his nephew Sava Kosanović. Shortly thereafter Tesla's papers and other property were impounded by the United States' Alien Property Custodian office in Tesla's compound at the Manhattan Warehouse, even though he was a naturalized citizen.

Dr. John G. Trump was the main government official who went over Tesla's secret papers after his death in 1943. At the time, Trump was a well-known electrical engineer serving as a technical aide to the National Defense Research Committee of the Office of Scientific Research & Development, Technical Aids, Div. 14, NTRC (predecessor agency to the CIA's Office of Scientific Intelligence). Trump was also a professor at M.I.T., and had his feelings hurt by Tesla's 1938 review and critique of M.I.T.'s huge Van de Graaff generator with its two thirty-foot towers and two 15-foot-diameter (4.6 m) balls, mounted on railroad tracks—which Tesla showed could be out-performed in both voltage and current by one of his tiny coils about two feet tall.^{[124][dubious – discuss]} Trump was asked to participate in the examination of Tesla's papers at the Manhattan Warehouse & Storage Co. Trump reported afterwards that no examination had been made of the vast amount of Tesla's property that had been in the basement of the New Yorker Hotel ten years prior to Tesla's death, or of any of his papers, except those in his immediate possession at the time of his death. Trump concluded in his report that there was nothing that would constitute a hazard in unfriendly hands.

After the FBI was contacted by the War Department, his papers were declared to be top secret. The personal effects were sequestered on the advice of presidential advisers; J. Edgar Hoover declared the case most secret, because of the nature of Tesla's inventions and patents.^[125] One document stated that "[he] is reported to have some 80 trunks in different places containing transcripts and plans having to do with his experiments [...]". Altogether, in Tesla's effects, there were the contents of his safe, two truckloads of papers and apparatuses from his hotel, another 75 packing crates and trunks in a storage facility, and another 80 large storage trunks in another storage facility. The Navy and several "federal officials" spent two days microfilming some of the material at the Office of Alien Properties storage facility in 1943, and that was it, until Oct., 1945.^[126]

Tesla's family and the Yugoslav embassy struggled with the American authorities to gain these items after his death because of the potential significance of some of his research. Eventually Mr. Kosanović won possession of the materials, which are now housed in the Nikola Tesla Museum.^[127]

Literary works[link]

Apart from doing pure work on inventing things, Tesla also wrote a number of books and articles for magazines and journals.^[128] Among his books are My Inventions: The Autobiography of Nikola Tesla, The Fantastic Inventions of Nikola Tesla and The Tesla Papers.

A number of Tesla's writings are freely available on the web,^{[129][130][131]} including the article The Problem of Increasing Human Energy which he wrote for The Century Magazine,^[132][133] and the article Experiments With Alternate Currents Of High Potential And High Frequency published in his book Inventions, Researches and Writings of Nikola Tesla.^[134][135]

Legacy and honors[link]

Nikola Tesla on contemporary 100 Serbian dinar banknote.

Nikola Tesla Corner in New York

• The tesla (symbol T) – compound derived SI unit of magnetic flux density.^[136]
• Tesla – a crater on the far side of the moon of 26 kilometers in diameter at −2,0° width, −132.0° height.^[137]
• 2244 Tesla – a minor planet.^[137]
• TPP Nikola Tesla – the largest power plant in Serbia.
• The rock band Tesla takes its name from Nikola Tesla.^[138]
• An electric car company, Tesla Motors, named their company in tribute to Tesla.^[139]
• The Belgrade Nikola Tesla Airport is named in his honor.^[140]
• Google honoured Tesla on his birthday on 10 July 2009 by displaying a doodle in the Google search home page, that showed the G as a tesla coil.^[141][142]
• The Czechoslovakian electro-technical company Tesla
• Tesla Motors, a manufacturer of electric cars based in Palo Alto, California, is named for him.
• The street sign “Nikola Tesla Corner” at the corner of the 40th Street and 6th Avenue in Manhattan
• The United States Postal Service honored Tesla with a commemorative stamp in 1983.
• Tesla was inducted into the Inventor’s Hall of Fame in 1975.
• The Nikola Tesla Award^[143]

Monuments[link]

Nikola Tesla monument by Les Drysdale in Niagara Falls, Ontario.

The Nikola Tesla Memorial Centre located in his birthplace of Smiljan near the town of Gospić in Croatia opened in 2006 features a statue of Tesla designed by sculptor Mile Blažević.^[144][145] On 7 July 2006 on the corner of Masarykova and Preradovićeva streets in the Lower Town area in Zagreb the monument to Tesla was unveiled. This monument was designed by Ivan Meštrović in 1952 and was transferred from the Zagreb-based Ruđer Bošković Institute where it had spent previous decades.

A monument to Tesla was established at Niagara Falls, New York. This monument, sculpted by Frano Kršinić and portraying Tesla reading a set of notes, was presented to the United States by Yugoslavia in 1976 and is an identical copy of the monument standing in front of the University of Belgrade Faculty of Electrical Engineering. Another monument to Tesla, featuring him standing on a portion of an alternator, was established at Queen Victoria Park in Niagara Falls, Ontario, Canada. The monument was officially unveiled on 9 July 2006 on the 150th anniversary of Tesla's birth. The monument was sponsored by St. George Serbian Church, Niagara Falls, and designed by Les Drysdale of Hamilton, Ontario. Drysdale's design was the winning design from an international competition.

In 1994, acting on the advice of the President's Advisory Council on Historic Preservation, a formal nomination process was initiated by the Tesla Wardenclyffe Project seeking placement of the Wardenclyffe laboratory-office building and the Tesla tower foundation on both the New York State and National Registers of Historic Places. This would result in the creation of a monument to Tesla out of the Wardenclyffe site itself.^[146]

Portrayals in popular culture[link]

Nikola Tesla has appeared in popular culture as a character in books, films, radio, TV, music, live theatre, comics and video games. The lack of recognition received by Tesla during his own lifetime has made him a tragic and inspirational character well suited to dramatic fiction. The impact of the technologies invented by Tesla is a recurring theme in several types of science fiction.

See also[link]

Electronics portal

• Electrical Experimenter
• List of Tesla patents
• Timeline of low-temperature technology

References[link]

Notes[link]