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{{Short description|Serbian-American engineer and inventor (1856–1943)}}
{{redirect|Tesla|other uses of Tesla|Tesla (disambiguation)|other uses of Nikola Tesla|Nikola Tesla (disambiguation)}}
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{{Infobox person
{{Use American English|date=September 2024}}
| honorific_prefix =
{{Use dmy dates|date=September 2024}}
| name = Nikola Tesla
{{Infobox engineer
| image = Tesla circa 1890.jpeg
| native_name = {{nobold|{{lang|sr|Никола Тесла}}}}
| image_size =
| native_name_lang = sr
| alt =
| caption = Tesla, aged 34, 1890, photo by ] | image = Tesla circa 1890.jpeg
| alt = Head-and-shoulder photograph of a slender man with dark hair and moustache, dark suit and white-collar shirt
| native_name =
| caption = Tesla, {{circa|1890}}
| native_name_lang =
| birth_date = {{birth date|1856|7|10|df=y}}
| nationality =
| birth_place = ], ]<br>(now ])<!-- There is consensus against adding ] here -->
| citizenship = ] (10 July 1856&nbsp;– 1867)<br />] (30 July 1891&nbsp;– 7 January 1943)
| death_date = {{death date and age|1943|1|7|1856|7|10|df=y}}
| birth_name =
| death_place = New York City, U.S.
| birth_date = {{Birth date|1856|7|10|df=yes}}
| resting_place = ], ], Serbia
| birth_place = ], ] (modern-day ])
| citizenship = Austria (1856–1891)<br>United States (1891–1943)
| death_date = {{Death date and age|1943|1|7|1856|7|10|df=yes}}
| alma_mater = ] (dropped out)
| death_place = ], ], ]
| occupation = {{hlist|Engineer|futurist|inventor}}
| resting_place =
| known_for =
| resting_place_coordinates =
| awards = {{ubl
| education = ] (dropped out)
| ] (1892)
| module = {{infobox engineering career
| ] (1894)
| discipline = Electrical engineering<br />Mechanical engineering
| ] (1895)
| institutions =
| ] (1931)
| practice_name =
| ] (1937)
| employer =
| ] (1937)
| significant_projects = ],<br />high-voltage, high-frequency power experiments
}}
| significant_design = ]<br />]<br />]<br />Radio ] (])<ref name=Jonnes />{{Rp|355}}
| discipline = {{ubl
| significant_advance =
| ]
| significant_awards = {{collapsible list | title = {{nbsp}}|], II Class, Government of Serbia (1892)<br />] (1894)<br />] (1895)<br />] (1916)<br />], I Class, Government of Yugoslavia (1926)<br />] (1931)<br />] (1934)<br />], I Class, Government of Yugoslavia (1936)<br />], I Class, Government of Czechoslovakia (1937)<br />] (1937)<br />], Sofia, Bulgaria (1939)}}
| ]}}
}}
| employer =
| signature = TeslaSignature.svg
| significant_design = ]
| signature_alt =
| significant_projects = ]
| significant_advance = ]
| significant_awards = {{ubl
|] (1916)
|] (1934)}}
| signature = Nikola Tesla signature 1900.svg
}} }}
'''Nikola Tesla''' ({{IPAc-en|ˈ|n|ɪ|k|ə|l|ə| |ˈ|t|ɛ|s|l|ə}};<ref name="Webster's"> {{Webarchive|url=https://web.archive.org/web/20211024010805/https://www.dictionary.com/browse/tesla |date=24 October 2021 }}. '']''.</ref> {{Lang-sr-Cyrl|Никола Тесла}}, {{IPA|sh|nǐkola têsla| }}; 10 July 1856&nbsp;– 7 January 1943) was a<!-- PLEASE DO NOT CHANGE NATIONALITY OR ETHNICITY--> Serbian-American<!-- SEE Talk:Nikola Tesla/Nationality and ethnicity -->{{sfn|Burgan|2009|p=9}}<ref>{{cite news |title=Electrical pioneer Tesla honoured |url=http://news.bbc.co.uk/1/hi/world/europe/5167054.stm |publisher=BBC News |access-date=20 May 2013 |date=10 July 2006 |archive-date=10 October 2020 |archive-url=https://web.archive.org/web/20201010073256/http://news.bbc.co.uk/1/hi/world/europe/5167054.stm |url-status=live }}</ref> engineer, ], and inventor. He is known for his contributions to the design of the modern ] (AC) ] system.<ref>{{cite book |last=Laplante |first=Phillip A. |url=https://books.google.com/books?id=soSsLATmZnkC |title=Comprehensive Dictionary of Electrical Engineering 1999 |page=635 |publisher=Springer |year=1999 |isbn=978-3-540-64835-2 }}</ref>


Born and raised in the ], Tesla first studied engineering and physics in the 1870s without receiving a degree. He then gained practical experience in the early 1880s working in ] and at ] in the new ]. In 1884 he immigrated to the United States, where he became a ]. He worked for a short time at the ] in New York City before he struck out on his own. With the help of partners to finance and market his ideas, Tesla set up laboratories and companies in New York to develop a range of electrical and mechanical devices. His AC ] and related ] AC patents, licensed by ] in 1888, earned him a considerable amount of money and became the cornerstone of the ] which that company eventually marketed.
'''Nikola Tesla''' ({{lang-sr-cyr|Никола Тесла}}; 10 July 1856&nbsp;– 7 January 1943) was a ]<ref>{{cite book |last=Burgan |first=Michael |title=Nikola Tesla: Inventor, Electrical Engineer |year=2009 |publisher=Capstone |location=Mankato, Minnesota |isbn=978-0-7565-4086-9 |url=http://books.google.ca/books?id=PW06qF-dj2IC&printsec=frontcover |ref=harv |page=9}}</ref><ref>{{cite news |title=Electrical pioneer Tesla honoured |url=http://news.bbc.co.uk/1/hi/world/europe/5167054.stm |publisher=BBC News |accessdate=20 May 2013 |date=10 July 2006}}</ref><ref name="History-bio">{{cite web |url=http://www.history.com/topics/inventions/nikola-tesla |title=Nikola Tesla |publisher=] |accessdate=15 June 2014 |quote=Serbian-American engineer and physicist Nikola Tesla (1856–1943) made dozens of breakthroughs in the production, transmission and application of electric power.}}</ref><ref name="Bio" /> inventor, ], ], and ] best known for his contributions to the design of the modern ] (AC) ] system.<ref>{{cite book |last=Laplante |first=Phillip A. |url=http://books.google.co.uk/books?id=soSsLATmZnkC |title=Comprehensive Dictionary of Electrical Engineering 1999 |page=635 |publisher=Springer |year=1999|isbn=9783540648352 }}</ref>


Tesla gained experience in ] and electrical engineering before immigrating to the ] in 1884 to work for ] in New York City. He soon struck out on his own with financial backers, setting up laboratories and companies to develop a range of electrical devices. His ]ed AC ] and transformer were licensed by ], who also hired Tesla for a short time as a consultant. His work in the formative years of electric power development was also involved in the corporate struggle between making alternating current or ] the power transmission standard, referred to as the ]. Tesla went on to pursue his ideas of wireless lighting and electricity distribution in his high-voltage, high-frequency power experiments in New York and Colorado Springs and made early (1893) pronouncements on the possibility of ] with his devices. He tried to put these ideas to practical use in his ill-fated attempt at intercontinental wireless transmission, which was his unfinished ] project.<ref name="tsteslatower">{{cite web |title=Tesla Tower in Shoreham Long Island (1901–1917) meant to be the "World Wireless" Broadcasting system |url=http://www.teslasociety.com/teslatower.htm |publisher=Tesla Memorial Society of New York |accessdate=3 June 2012}}</ref> In his lab he also conducted a range of experiments with mechanical oscillators/generators, electrical discharge tubes, and early X-ray imaging. He even built a wireless controlled boat, one of the first ever exhibited. Attempting to develop inventions he could patent and market, Tesla conducted a range of experiments with mechanical ]/generators, ] tubes, and early ]. He also built a ]ly controlled boat, one of the first ever exhibited. Tesla became well known as an inventor and demonstrated his achievements to celebrities and wealthy patrons at his lab, and was noted for his showmanship at public lectures. Throughout the 1890s, Tesla pursued his ideas for wireless lighting and worldwide wireless electric power distribution in his high-voltage, high-frequency power experiments in New York and ]. In 1893, he made pronouncements on the possibility of ] with his devices. Tesla tried to put these ideas to practical use in his unfinished ] project, an intercontinental wireless communication and power transmitter, but ran out of funding before he could complete it.


Tesla was renowned for his achievements and showmanship, eventually earning him a reputation in popular culture as an archetypal "]."<ref>{{harvnb|Van Riper|2011}}</ref> His patents earned him a considerable amount of money, much of which was used to finance his own projects with varying degrees of success.<ref name=Cheney>{{cite book |url=http://books.google.com/books/about/Tesla.html?id=8b-Dp_2KmJoC |title=Tesla: Man Out of Time |publisher=Simon & Schuster |author=Cheney, Margaret |year=2001 |isbn=0-7432-1536-2}}</ref>{{Rp|121,154}} He lived most of his life in a series of New York hotels, through his retirement. He died on 7 January 1943.<ref>{{cite book |last=O'Shei |first=Tim |title=Marconi and Tesla: Pioneers of Radio Communication |year=2008 |publisher=MyReportLinks.com Books |isbn=978-1-59845-076-7 |page=106}}</ref> His work fell into relative obscurity after his death, but in 1960 the ] named the ] of magnetic flux density the ] in his honor.<ref>{{cite web |title=Welcome to the Tesla Memorial Society of New York Website |url=http://www.teslasociety.com/mri_digest.htm |publisher=Tesla Memorial Society of New York |accessdate=3 June 2012}}</ref> Tesla has experienced a resurgence in interest in popular culture since the 1990s.<ref>{{harvnb|Van Riper|2011|p=150}}</ref> After Wardenclyffe, Tesla experimented with a series of inventions in the 1910s and 1920s with varying degrees of success. Having spent most of his money, Tesla lived in a series of New York hotels, leaving behind unpaid bills. He died in New York City in January 1943.<ref>{{cite book|last=O'Shei|first=Tim|title=Marconi and Tesla: Pioneers of Radio Communication|year=2008|publisher=MyReportLinks.com Books|isbn=978-1-59845-076-7|page=106}}</ref> Tesla's work fell into relative obscurity following his death, until 1960, when the ] named the ] (SI) measurement of ] the ] in his honor. There has been a resurgence in popular interest in Tesla since the 1990s.<ref>{{harvnb|Van Riper|2011|p=150}}</ref>


==Early years{{anchor|Parents}}==<!-- ] and ] redirect here -->
== Early years (1856–1885) ==
]. The site was made into ].<ref name="tsbirthplace">{{cite web |title=Pictures of Tesla's home in Smiljan, Croatia and his father's church after rebuilding. |url=http://www.teslasociety.com/birthplace.htm |access-date=22 May 2013 |publisher=Tesla Memorial Society of NY |archive-date=2 June 2003 |archive-url=https://web.archive.org/web/20030602202049/http://www.teslasociety.com/birthplace.htm |url-status=live }}</ref>]]
<!-- ] and ] redirect here -->
], {{circa|1880}}.]]
], ], where he was born, and the rebuilt church, where his father served. During the ], several of the buildings were severely damaged by fire. They were restored and reopened in 2006.<ref name="tsbirthplace" />]]
]
] priest in the village of ].]]


Nikola Tesla was born into an ethnic ] family in the village of ], within the ], in the ] (present-day ]), on 10 July 1856.{{sfn|Cheney|Uth|Glenn|1999|p=143}}{{sfn|O'Neill|1944|pp=9, 12}} His father, Milutin Tesla (1819–1879),{{sfn|Carlson|2013|p=14}} was a priest of the ].{{sfn|Dommermuth-Costa|1994|p=12|loc="Milutin, Nikola's father, was a well-educated priest of the Serbian Orthodox Church."}}{{sfn|Cheney|2011|p=25|loc="The tiny house in which he was born stood next to the Serbian Orthodox Church presided over by his father, the Reverend Milutin Tesla, who sometimes wrote articles under the nom-de-plume 'Man of Justice'"}}{{sfn|Carlson|2013|p=14|loc="Following a reprimand at school for not keeping his brass buttons polished, he quit and instead chose to become a priest in the Serbian Orthodox Church"}}{{sfn|Burgan|2009|p=17|loc="Nikola's father, Milutin was a Serbian Orthodox priest and had been sent to Smiljan by his church."}} His father's brother Josif was a lecturer at a military academy who wrote several textbooks on mathematics.{{sfn|Carlson|2013|page=14}}
Nikola Tesla was born on 10 July <small>(] 28 June)</small> 1856 to ] parents in the village of ], ] (modern-day ]).<ref name=ONeill>{{cite book |url=http://books.google.com/books/about/Prodigal_Genius.html?id=40NzjS5FunkC |title=Prodigal Genius: The Life of Nikola Tesla |publisher=Ives Washburn |author=O'Neill, John Joseph |year=1944 |isbn=0-914732-33-1}}</ref><ref>{{harvnb|O'Neill|2007|p=369|ps=: "Tesla was born in the village of Smiljan near the town of Gospic, Austrian Empire, Croatian Krajina."}}</ref> His father, Milutin Tesla, was an ] priest.<ref name="Bio">{{cite web |url=http://www.britannica.com/EBchecked/topic/588597/Nikola-Tesla |title=Tesla, Nikola |work=Encyclopædia Britannica |accessdate=7 June 2014}}</ref> Tesla's mother, Đuka Tesla (''née'' Mandić), whose father was also an Orthodox priest,<ref name=ONeill />{{Rp|10}} had a talent for making home craft tools, mechanical appliances, and the ability to memorize ]. Đuka had never received a formal education. Nikola credited his ] and creative abilities to his mother's genetics and influence.<ref name=Cheney /><ref name="Seifer 2001 7">{{harvnb|Seifer|2001|p=7}}</ref> Tesla's progenitors were from western Serbia, near Montenegro.<ref name=ONeill />{{Rp|12}}


Tesla's mother, Georgina "Đuka" Mandić (1822–1892), whose father was also an Eastern Orthodox Church priest,{{sfn|O'Neill|1944|p=10}} had a talent for making home craft tools and mechanical appliances and the ability to memorize ]. Đuka had never received a formal education. Tesla credited his ] and creative abilities to his mother's genetics and influence.{{sfn|Cheney|2001|pp=25-26}}{{sfn|Seifer|2001|p=7}}
Tesla was the fourth of five children. He had an older brother named Dane and three sisters, Milka, Angelina and Marica. Dane was killed in a horse-riding accident when Nikola was five.<ref>W. Bernard Carlson, Tesla: Inventor of the Electrical Age, p. 21</ref> In 1861, Tesla attended the "Lower" or "Primary" School in Smiljan where he studied German, arithmetic, and religion.<ref name="teslauniverse4" /> In 1862, the Tesla family moved to ], Austrian Empire, where Tesla's father worked as a pastor. Nikola completed "Lower" or "Primary" School, followed by the "Lower Real Gymnasium" or "Normal School."<ref name=Tesla-Timeline />


Tesla was the fourth of five children. He had three sisters, Milka, Angelina, and Marica, and an older brother named Dane, who was killed in a horse-riding accident when Tesla was aged six or seven.{{sfn|Carlson|2013|p=21}} In 1861, Tesla attended primary school in Smiljan where he studied German, arithmetic, and religion. In 1862, the Tesla family moved to the nearby town of ], where Tesla's father worked as parish priest. Nikola completed primary school, followed by middle school. In 1870, Tesla moved to ]{{sfn|Seifer|2001|p=13}} to attend high school at the ] where the classes were held in German, as it was usual throughout schools within the Austro-Hungarian ].<ref>{{cite book|last1=Tesla|first1=Nikola|last2=Marinčić|first2=Aleksandar|title=From Colorado Springs to Long Island: research notes |date=2008|publisher=Nikola Tesla Museum|location=Belgrade|isbn=978-86-81243-44-2}}</ref><ref>{{cite book |last1=Budiansky |first1=Stephen |title=Journey to the edge of reason : the life of Kurt Gödel |date=2021 |location=New York, NY |isbn=978-1-324-00545-2 |edition=First |quote=In the natural sciences, Austria produced a remarkable number of talented theorists and experimentalists. The electrical genius Nikola Tesla, from Croatia, studied in Karlovac at one of the rigorous German-language high schools, the Gymnasiums, established throughout the Austrian Empire.}}</ref> Later in his patent applications, before he obtained American citizenship, Tesla would identify himself as 'of Smiljan, ], border country of ]'.{{sfn|Wohinz|2019|pp=14–15}}
In 1870, Tesla moved to ] to attend school at ], where he was profoundly influenced by a math teacher Martin Sekulić.<ref name=ONeill />{{Rp|32}}<ref name="teslauniverse2" /> Tesla was able to perform integral calculus in his head, which prompted his teachers to believe that he was cheating.<ref>{{cite web |title=Tesla Life and Legacy&nbsp;– Tesla's Early Years |url=http://www.pbs.org/tesla/ll/ll_early.html |publisher=PBS |accessdate=8 July 2012}}</ref> He finished a four-year term in three years, graduating in 1873.<ref name=ONeill />{{Rp|33}}


] priest in the village of Smiljan.|left]]
In 1873, Tesla returned to his birthtown, Smiljan. Shortly after he arrived, Tesla contracted ]; he was bedridden for nine months and was near death multiple times. Tesla's father, in a moment of despair, promised to send him to the best engineering school if he recovered from the illness<ref name="teslauniverse2" /><ref name="tesla1">{{cite web |last=Tesla |first=Nikola |title=My Inventions The Autobiography of Nikola Tesla |url=http://www.lucidcafe.com/library/96jul/teslaautobio.html |accessdate=16 August 2012}}</ref> (his father had originally wanted him to enter the priesthood).<ref>{{cite book |last=Glenn |first=edited by Jim |title=The complete patents of Nikola Tesla |year=1994 |publisher=Barnes & Noble Books |location=New York |isbn=1-56619-266-8}}</ref>


Tesla later wrote that he became interested in demonstrations of electricity by his physics professor.{{efn|Tesla does not mention which professor this was by name, but some sources conclude this was ].{{sfn|Seifer|1998|loc=CHILDHOOD 1856-74}}{{sfn|Petešić|1976|pp=29–30}}}} Tesla noted that these demonstrations of this "mysterious phenomena" made him want "to know more of this wonderful force".{{sfn|Carlson|2013|p=32}} Tesla was able to perform ] in his head, which prompted his teachers to believe that he was cheating.<ref>{{cite web|title=Tesla Life and Legacy&nbsp;– Tesla's Early Years|url=https://www.pbs.org/tesla/ll/ll_early.html|publisher=PBS|access-date=8 July 2012|archive-date=20 July 2018|archive-url=https://web.archive.org/web/20180720022706/http://www.pbs.org/tesla/ll/ll_early.html|url-status=live}}</ref> He finished a four-year term in three years, graduating in 1873.{{sfn|O'Neill|1944|p=33}}
In 1874, Tesla evaded being drafted into the ] in Smiljan<ref name=autogenerated6>{{harvnb|Seifer|2001}}</ref> by running away to ], near ]. There, he explored the mountains in hunter's garb. Tesla said that this contact with nature made him stronger, both physically and mentally.<ref name="teslauniverse2" /> He read many books while in Tomingaj, and later said that ]'s works had helped him to miraculously recover from his earlier illness.<ref name="tesla1" />


After graduating Tesla returned to Smiljan but soon contracted ], was bedridden for nine months and was near death multiple times. In a moment of despair, Tesla's father (who had originally wanted him to enter the priesthood),<ref>{{cite book|editor-last=Glenn|editor-first=Jim|title=The complete patents of Nikola Tesla|year=1994|publisher=Barnes & Noble Books|location=New York|isbn=1-56619-266-8|url=https://archive.org/details/completepatentso00tesl}}</ref> promised to send him to the best engineering school if he recovered from the illness.{{sfn|Carlson|2013|p=29}} Tesla later said that he had read ]'s earlier works while recovering from his illness.<ref name="tesla1">{{cite book|last1=Tesla|first1=Nikola|title=My inventions: the autobiography of Nikola Tesla|date=2011 | orig-date = 1919 edition reprint | publisher=Martino Fine Books|location=Eastford|isbn=978-1-61427-084-3}}</ref><ref>{{cite news |first=Juliana |last=Adelman |title=The electricity between Mark Twain and Nikola Tesla |url=https://www.irishtimes.com/news/science/the-electricity-between-mark-twain-and-nikola-tesla-1.2522523 |newspaper=The Irish Times |date=11 February 2016}}</ref>
In 1875, Tesla enrolled at ] in ], ], on a ] scholarship. During his first year, Tesla never missed a lecture, earned the highest grades possible, passed nine exams<ref name="teslauniverse2">{{cite web |title=Tesla Timeline |url=http://www.teslauniverse.com/nikola-tesla-timeline-1861-dane-tesla-dies |publisher=Tesla Universe |accessdate=16 August 2012}}</ref><ref name="tesla1" /> (nearly twice as many required<ref name=ONeill />), started a Serbian culture club,<ref name="teslauniverse2" /> and even received a letter of commendation from the dean of the technical faculty to his father, which stated, "Your son is a star of first rank."<ref name=ONeill /> Tesla claimed that he worked from 3&nbsp;a.m. to 11&nbsp;p.m., no Sundays or holidays excepted.<ref name="tesla1" /> He was "mortified when father made light of hard won honors." After his father's death in 1879,<ref name=autogenerated6 /> Tesla found a package of letters from his professors to his father, warning that unless he were removed from the school, Tesla would be killed through overwork.<ref name="tesla1" /> During his second year, Tesla came into conflict with Professor Poeschl over the ], when Tesla suggested that commutators weren't necessary. At the end of his second year, Tesla lost his scholarship and became addicted to gambling.<ref name="teslauniverse2" /><ref name="tesla1" /> During his third year, Tesla gambled away his allowance and his tuition money, later gambling back his initial losses and returning the balance to his family. Tesla said that he "conquered passion then and there," but later he was known to play billiards in the US. When exam time came, Tesla was unprepared and asked for an extension to study, but was denied. He never graduated from the university and did not receive grades for the last semester.<ref name=autogenerated6 />


The next year Tesla evaded ] into the ] in Smiljan{{sfn|Seifer|2001|p=14}} by running away southeast of Lika to ], near ]. There he explored the mountains wearing hunter's garb. Tesla said that this contact with nature made him stronger, both physically and mentally. He enrolled at the ] in 1875 on a Military Frontier scholarship. Tesla passed nine exams (nearly twice as many as required{{sfn|O'Neill|1944|p=39}}) and received a letter of commendation from the dean of the technical faculty to his father, which stated, "Your son is a star of first rank."{{sfn|O'Neill|1944|p=39}} At Graz, Tesla noted his fascination with the detailed lectures on electricity presented by Professor ] and described how he made suggestions on improving the design of an electric motor the professor was demonstrating.<ref name="tesla1" />{{better source needed|date=January 2022}}{{sfn|Carlson|2013|pp=35}} But by his third year he was failing in school and never graduated, leaving ] in December 1878. One biographer suggests Tesla was not studying and may have been expelled for gambling and womanizing.{{sfn|Seifer|2001|p=17}}
In December 1878, Tesla left Graz and severed all relations with his family to hide the fact that he dropped out of school.<ref name=autogenerated6 /> His friends thought that he had drowned in the ].<ref name="autogenerated1">{{harvnb|Seifer|2001|p=18}}</ref> Tesla went to ] (now in ]), where he worked as a draftsman for 60 florins a month. He spent his spare time playing cards with local men on the streets.<ref name=autogenerated6 /> In March 1879, Milutin Tesla went to Maribor to beg his son to return home, but Nikola refused.<ref>{{cite web |title=Tesla Timeline |url=http://www.teslauniverse.com/nikola-tesla-timeline-1862-tesla-moves-to-gospic#goto-1878 |publisher=Tesla Universe |accessdate=16 August 2012}}</ref> Nikola suffered a ] at around the same time.<ref name="autogenerated1" />
]


]
On 24 March 1879, Tesla was returned to Gospić under police guard for not having a residence permit. On 17 April 1879, Milutin Tesla died at the age of 60 after contracting an unspecified illness<ref name="teslauniverse5">{{cite web |title=Tesla Timeline |url=http://www.teslauniverse.com/nikola-tesla-timeline-1862-tesla-moves-to-gospic#goto-1879 |publisher=Tesla Universe |accessdate=16 August 2012}}</ref> (although some sources say that he died of a stroke<ref>{{cite web |title=Timeline of Nikola tesla |url=http://www.teslasociety.org/timeline.html |publisher=tesla memorial society of ny |accessdate=1 December 2012}}</ref> ). During that year, Tesla taught a large class of students in his old school, Higher Real Gymnasium, in Gospić.<ref name="teslauniverse5" />


Tesla's family did not hear from him after he left school.{{sfn|Seifer|2001|pp=17–18}} There was a rumor among his classmates that he had drowned in the nearby river ] but in January one of them ran into Tesla in the town of ] and reported that encounter to Tesla's family.{{sfn|Carlson|2013|pp=47}} It turned out Tesla had been working there as a draftsman for 60 florins per month.{{sfn|Seifer|2001|p=17}} In March 1879, Milutin finally located his son and tried to convince him to return home and take up his education in Prague.{{sfn|Carlson|2013|pp=47}} Tesla returned to Gospić later that month when he was deported for not having a residence permit.{{sfn|Carlson|2013|pp=47}} Tesla's father died the next month, on 17 April 1879, at the age of 60 after an unspecified illness.{{sfn|Carlson|2013|pp=47}} During the rest of the year Tesla taught a large class of students in his old school in Gospić.
In January 1880, two of Tesla's uncles put together enough money to help him leave Gospić for ] where he was to study. Unfortunately, he arrived too late to enroll at ]; he never studied Greek, a required subject; and he was illiterate in ], another required subject. Tesla did, however, attend lectures at the university, although, as an auditor, he did not receive grades for the courses.<ref>{{cite web |title=Tesla Timeline |url=http://www.teslauniverse.com/nikola-tesla-timeline-1862-tesla-moves-to-gospic#goto-1880 |publisher=Tesla Universe |accessdate=16 August 2012}}</ref><ref>{{cite book |last=Mrkich |first=D. |title=Nikola Tesla: the european years |year=2003 |publisher=Commoner's Publishing |location=Ottawa |isbn=0-88970-113-X |edition=1st ed.}}</ref><ref>{{cite web |title=NYHOTEL |url=http://www.teslasociety.com/nyhotel.htm |publisher=Tesla Society of NY |accessdate=17 August 2012}}</ref>


In January 1880, two of Tesla's uncles put together enough money to help him leave Gospić for ], where he was to study. He arrived too late to enroll at ]; he had never studied ], a required subject; and he was illiterate in ], another required subject. Tesla did, however, attend lectures in philosophy at the university as an auditor but he did not receive grades for the courses.<ref>{{cite book|last=Mrkich|first=D.|title=Nikola Tesla: The European Years|year=2003|publisher=Commoner's Publishing|location=Ottawa|isbn=0-88970-113-X|edition=1st}}</ref><ref>{{cite web|title=NYHOTEL|url=http://www.teslasociety.com/nyhotel.htm|publisher=Tesla Society of NY|access-date=17 August 2012|archive-date=31 December 2018|archive-url=https://web.archive.org/web/20181231231421/http://www.teslasociety.com/nyhotel.htm|url-status=live}}</ref>
In 1881, Tesla moved to ] to work under Ferenc Puskas at a ] company, the Budapest Telephone Exchange. Upon arrival, Tesla realized that the company, then under construction, was not functional, so he worked as a draftsman in the Central Telegraph Office instead. Within a few months, the Budapest Telephone Exchange became functional and Tesla was allocated the chief electrician position.<ref>{{cite web |title=Tesla Timeline |url=http://www.teslauniverse.com/nikola-tesla-timeline-1881-tesla-works-in-budapest?PHPSESSID=b2ac3fd9ddbac330fbfd29e6dd44a509; |publisher=Tesla Universe |accessdate=17 August 2012}}</ref> During his employment, Tesla made many improvements to the Central Station equipment and claimed to have perfected a telephone ] or ], which was never patented nor publicly described.<ref name="tesla1" />


=== Working for Edison === === Working at Budapest Telephone Exchange ===
In 1882, Tesla began working for the Continental Edison Company in France, designing and making improvements to electrical equipment.<ref>{{cite web |url=http://topdocumentaryfilms.com/nikola-tesla-the-genius/ |title=Nikola Tesla: The Genius Who Lit the World |publisher=Top Documentary Films}}</ref> In June 1884, he relocated to ]<ref name=ONeill />{{Rp|57–60}}<ref name="PBS">{{cite web |url=http://www.pbs.org/tesla/ll/ll_america.html |title=Coming to America |publisher=] |accessdate=14 November 2010}}</ref> where he was hired by ] to work for his Edison Machine Works. Tesla's work for Edison began with simple electrical engineering and quickly progressed to solving more difficult problems.<ref>{{cite book |title=American inventors, entrepreneurs & business visionaries |last=Carey |first=Charles W. |year=1989 |publisher=Infobase Publishing |isbn=0-8160-4559-3 |page=337 |url=http://books.google.com/?id=XKiGgl36bkgC |accessdate=27 November 2010}}</ref>


Tesla moved to ], ], in 1881 to work under ] at a ] company, the Budapest Telephone Exchange. Upon arrival, Tesla realized that the company, then under construction, was not functional, so he worked as a draftsman in the Central Telegraph Office instead. Within a few months, the Budapest Telephone Exchange became functional, and Tesla was allocated the chief electrician position. During his employment, Tesla made many improvements to the Central Station equipment and claimed to have perfected a telephone ] or ], which was never patented nor publicly described.<ref name="tesla1" />{{better source needed|date=January 2022}}
Tesla was offered the task of completely redesigning the Edison Company's ] ]. In 1885, he said that 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"<ref name=Cheney />{{Rp|54–57}}—this has been noted as an odd statement from an Edison whose company was stingy with pay and who did not have that sort of cash on hand.<ref name=Jonnes />{{Rp|110}} After months of work, Tesla fulfilled the task and inquired about payment. Edison, saying that he was only joking, replied, "Tesla, you don't understand our ]."<ref name=ONeill />{{Rp|64}}<ref>{{harvnb|Pickover|1999|p=14}}</ref> Instead, Edison offered a US$10 a week raise over Tesla's US$18 per week salary; Tesla refused the offer and immediately resigned.<ref name=Cheney />


== Middle years (1886–1899) == == Working at Edison ==
After leaving Edison's company Tesla partnered with two businessmen in 1886, Robert Lane and Benjamin Vale, who agreed to finance an electric lighting company in Tesla's name, ].<ref>Marc Seifer, Wizard: The Life And Times Of Nikola Tesla: The Life and Times of Nikola Tesla, p. 41</ref> The company installed electrical ] based illumination systems designed by Tesla and also had designs for dynamo electric machine commutators, the first patents issued to Tesla in the US.<ref name=Jonnes />


In 1882, Tivadar Puskás got Tesla another job in Paris with the Continental Edison Company.<ref>{{cite web |url=https://topdocumentaryfilms.com/nikola-tesla-the-genius/ |title=Nikola Tesla: The Genius Who Lit the World |publisher=Top Documentary Films |access-date=24 October 2021 |archive-date=26 April 2019 |archive-url=https://web.archive.org/web/20190426020752/https://topdocumentaryfilms.com/nikola-tesla-the-genius/ |url-status=live }}</ref> Tesla began working in what was then a brand new industry, installing indoor incandescent lighting citywide in large scale electric power ]. The company had several subdivisions and Tesla worked at the Société Electrique Edison, the division in the ] suburb of Paris in charge of installing the lighting system. There he gained a great deal of practical experience in electrical engineering. Management took notice of his advanced knowledge in engineering and physics and soon had him designing and building improved versions of generating ]s and motors.{{sfn|Carlson|2013|pp=63–64}} They also sent him on to troubleshoot engineering problems at other Edison utilities being built around France and in Germany.
The investors showed little interest in Tesla's ideas for new types of motors and electrical transmission equipment and also seemed to think it was better to develop an electrical utility than invent new systems.<ref name="W. Bernard Carlson page 75">W. Bernard Carlson, Tesla: Inventor of the Electrical Age, p. 75</ref> They eventually forced Tesla out leaving him penniless. He even lost control of the patents he had generated since he had assigned them to the company in lieu of stock.<ref name="W. Bernard Carlson page 75" /> He had to work at various electrical repair jobs and even as a ditch digger for $2 per day. Tesla considered the winter of 1886/1887 as a time of "terrible headaches and bitter tears." During this time, he questioned the value of his education.<ref name=Jonnes /><ref>{{cite web |title=Tesla Timeline |url=http://www.teslauniverse.com/nikola-tesla-timeline-1886-the-winter-of-suffering#goto-1886 |publisher=Tesla Universe |accessdate=17 July 2012}}</ref>


=== AC and the induction motor === === Moving to the United States ===
]s on Manhattan's lower east side, a "painful surprise".{{sfn|Carlson|2013|p=70}}]]
]


In 1884, Edison manager ], who had been overseeing the Paris installation, was brought back to the United States to manage the ], a manufacturing division situated in New York City, and asked that Tesla be brought to the United States as well.{{sfn|Carlson|2013|p=69}} In June 1884, Tesla emigrated{{sfn|O'Neill|1944|pp=57–60}} and began working almost immediately at the Machine Works on ]'s ], an overcrowded shop with a workforce of several hundred machinists, laborers, managing staff, and 20 "field engineers" struggling with the task of building the large electric utility in that city.<ref name="edison.rutgers.edu tesla">{{cite web|url=http://edison.rutgers.edu/tesla.htm|title=Edison & Tesla – The Edison Papers|website=edison.rutgers.edu|access-date=23 January 2017|archive-date=11 March 2019|archive-url=https://web.archive.org/web/20190311214910/http://edison.rutgers.edu/tesla.htm|url-status=live}}</ref> As in Paris, Tesla was working on troubleshooting installations and improving generators.<ref>{{cite book |title=American inventors, entrepreneurs & business visionaries |last=Carey |first=Charles W. |year=1989 |publisher=Infobase Publishing |isbn=0-8160-4559-3 |page=337 |url=https://books.google.com/books?id=XKiGgl36bkgC |access-date=27 November 2010 |archive-date=23 March 2024 |archive-url=https://web.archive.org/web/20240323123046/https://books.google.com/books?id=XKiGgl36bkgC |url-status=live }}</ref> Historian W. Bernard Carlson notes Tesla may have met company founder ] only a couple of times.<ref name="edison.rutgers.edu tesla" /> One of those times was noted in Tesla's autobiography where, after staying up all night repairing the damaged dynamos on the ocean liner {{SS|Oregon|1883|6}}, he ran into Batchelor and Edison, who made a quip about their "Parisian" being out all night. After Tesla told them he had been up all night fixing the ''Oregon'', Edison commented to Batchelor that "this is a damned good man".{{sfn|Carlson|2013|p=70}} One of the projects given to Tesla was to develop an ]-based street lighting system.{{sfn|Carlson|2013|pp=71–73}}<ref name="Notebook"> {{Webarchive|url=https://web.archive.org/web/20190226120239/https://teslauniverse.com/nikola-tesla/books/nikola-tesla-notebook-edison-machine-works-1884-1885 |date=26 February 2019 }} {{ISBN|86-81243-11-X}}, teslauniverse.com</ref> Arc lighting was the most popular type of street lighting but it required high voltages and was incompatible with the Edison low-voltage incandescent system, causing the company to lose contracts in some cities. Tesla's designs were never put into production, possibly because of technical improvements in incandescent street lighting or because of an installation deal that Edison made with an arc lighting company.{{sfn|Carlson|2013|pp=72–73}}
In late 1886 Tesla met Alfred S. Brown, a ] superintendent, and New York attorney Charles F. Peck. The two men were experienced in setting up companies and promoting inventions and patents for financial gain.<ref name="W. Bernard Carlson page 80">W. Bernard Carlson, Tesla: Inventor of the Electrical Age, p. 80</ref> Based on Tesla's patents and other ideas they agreed to back him financially and handle his patents. Together in April 1887 they formed the Tesla Electric Company with an agreement that profits from generated patents would go 1/3 to Tesla, 1/3 to Peck and Brown, and 1/3 to fund development.<ref name="W. Bernard Carlson page 80" /> They set up a laboratory for Tesla at 89 Liberty Street in Manhattan where he worked on improving and developing new types of electric motors, generators and other devices.


Tesla had been working at the Machine Works for a total of six months when he quit.<ref name="edison.rutgers.edu tesla" /> What event precipitated his leaving is unclear. It may have been over a bonus he did not receive, either for redesigning generators or for the arc lighting system that was shelved.{{sfn|Carlson|2013|pp=71–73}} Tesla had previous run-ins with the Edison company over unpaid bonuses he believed he had earned.{{sfn|Seifer|2001|pp=25, 34}}{{sfn|Carlson|2013|pp=69–73}} In his autobiography, Tesla stated the manager of the Edison Machine Works offered a $50,000 bonus to design "twenty-four different types of standard machines" "but it turned out to be a practical joke".<ref name="Autobiography-1919">{{Cite web|url=http://www.tfcbooks.com/e-books/my_inventions.pdf|title=Nikola Tesla, ''My Inventions: The Autobiography of Nikola Tesla'', originally published: 1919, p. 19|access-date=23 January 2017|archive-date=12 April 2019|archive-url=https://web.archive.org/web/20190412052438/http://www.tfcbooks.com/e-books/my_inventions.pdf|url-status=live}}</ref>{{better source needed|date=February 2024}} Later versions of this story have Thomas Edison himself offering and then reneging on the deal, quipping "Tesla, you don't understand our American humor".{{sfn|O'Neill|1944|p=64}}<ref>{{harvnb|Pickover|1999|p=14}}</ref> The size of the bonus in either story has been noted as odd since Machine Works manager Batchelor was stingy with pay{{efn|Tesla's contemporaries remembered that on a previous occasion Machine Works manager Batchelor had been unwilling to give Tesla a $7 a week pay raise <ref>Seifer – ''Wizard: The Life and Times of Nikola Tesla'', p. 38</ref>}} and the company did not have that amount of cash (equal to ${{Inflation|US|50000|1884|fmt=c}} today) on hand.{{sfn|Jonnes|2004|pp=109–110}}{{sfn|Seifer|2001|p=38}} Tesla's diary contains just one comment on what happened at the end of his employment, a note he scrawled across the two pages covering 7 December 1884, to 4 January 1885, saying "Good By to the Edison Machine Works".<ref name="Notebook" />{{sfn|Carlson|2013|p=73}}
One of the things Tesla developed at that laboratory in 1887 was an ] that ran on alternating current, a power system format that was starting to be built in Europe and the US because its advantages in long distance ] transmission. The motor used ] current which generated a ] to turn the motor (a principle Tesla claimed to have conceived of in 1882).<ref name="ReferenceB">{{cite book |title=Networks of power: electrification in Western society, 1880–1930 |publisher=JHU Press |page=117 |url=http://books.google.com/books?id=g07Q9M4agp4C&pg=PA117}}</ref><ref>Thomas Parke Hughes, Networks of Power: Electrification in Western Society, 1880–1930, pp. 115–118</ref><ref>{{cite book |url=http://books.google.com/books?id=1AsFdUxOwu8C&pg=PA204&lpg=PA204&dq=Tesla++Ferraris+induction+independent&source=bl&ots=u5KUDyGE2O&sig=Q-MxnMFjnKrr03xF3LyBdReYVtg&hl=en&sa=X&ei=R5J8UI3oNKLs0QH-rIHgCg&ved=0CEkQ6AEwBA#v=onepage&q=Tesla%20%20Ferraris%20induction%20independent&f=false |title=Robert Bud, Instruments of Science: An Historical Encyclopedia |page=204 |publisher=Books.google.com |accessdate=18 March 2013}}</ref> This innovative electric motor, patented in May 1888, was a simple self-starting design that did not need a ], thus avoiding sparking and the high maintenance of constantly servicing and replacing mechanical brushes.<ref name=Jonnes>{{cite book |url=http://books.google.com/books?id=BKX5UYWzVyQC&printsec=frontcover#v=onepage&q&f=false |title=Empires of Light: Edison, Tesla, Westinghouse, and the Race to Electrify the World |publisher=Random House |author=Jonnes, Jill |year=2004 |isbn=978-0-375-75884-3}}</ref>{{Rp|161}}<ref>Henry G. Prout, A Life of George Westinghouse, p. 129</ref>


== Tesla Electric Light and Manufacturing ==
In 1888, the editor of ''Electrical World'' magazine, ] (a friend and publicist), arranged for Tesla to demonstrate his alternating current system, including his induction motor, at the American Institute of Electrical Engineers (now ]).<ref>{{cite book |url=http://books.google.com/books?id=8j5bJ5OkGpgC&pg=PA36&lpg=PA36&dq=Westinghouse+tesla++Electrical+Engineers&source=bl&ots=5nHK8Hlhi1&sig=7NmfQ2iGm7IznasuUyl8Ce58bNQ&hl=en&sa=X&ei=1-xNUNb6Aonw0gGWv4H4Cg&ved=0CFMQ6AEwBg#v=onepage&q=Westinghouse%20tesla%20%20Electrical%20Engineers&f=false |author=Fritz E. Froehlich, Allen Kent |title=The Froehlich/Kent Encyclopedia of Telecommunications: Volume 17, |page=36 |publisher=Books.google.com |accessdate=10 September 2012}}</ref> Engineers working for the ] reported to ] that Tesla had a viable AC motor and related power system—something that Westinghouse had been trying to secure the patents to. Westinghouse looked into getting a patent on a similar commutatorless rotating magnetic field based induction motor presented in a paper in March 1888 by the Italian physicist ] but decided Tesla's patent would probably control the market.<ref name=Jonnes />{{Rp|160–162}}<ref name=Carlson>{{cite book |url=http://books.google.com/books?id=5I5c9j8BEn4C&printsec=frontcover&dq=Tesla:+Inventor+of+the+Electrical+Age&hl=en&sa=X&ei=XDujU8XNLOmxsATwuYDwDQ&ved=0CCAQ6AEwAA#v=snippet&q=Ferraris&f=false |title=Tesla: Inventor of the Electrical Age |publisher=Princeton University Press |author=Carlson, W. Bernard |year=2013 |isbn=978-1-4008-4655-9}}</ref>
Soon after leaving the Edison company, Tesla was working on patenting an arc lighting system,{{sfn|Jonnes|2004|pp=110–111}} possibly the same one he had developed at Edison.<ref name="edison.rutgers.edu tesla" /> In March 1885, he met with patent attorney Lemuel W. Serrell, the same attorney used by Edison, to obtain help with submitting the patents.{{sfn|Jonnes|2004|pp=110–111}} Serrell introduced Tesla to two businessmen, Robert Lane and Benjamin Vail, who agreed to finance an arc lighting manufacturing and utility company in Tesla's name, the ].{{sfn|Seifer|1998|p=41}} Tesla worked for the rest of the year obtaining the patents that included an improved DC generator, the first patents issued to Tesla in the US, and building and installing the system in ], New Jersey.{{sfn|Jonnes|2004|p=111}} Tesla's new system gained notice in the technical press, which commented on its advanced features.
]) in an 1888 {{US patent|390721}}.]]
In July 1888, Brown and Peck negotiated a licensing deal with George Westinghouse for Tesla's polyphase induction motor and transformer designs for $60,000 in cash and stock and a royalty of $2.50 per AC horsepower produced by each motor. Westinghouse also hired Tesla for one year for the large fee of $2,000 (${{Inflation|US|2000|1888|r=-2|fmt=c}} in today's dollars{{Inflation-fn|US}}) per month to be a consultant at the Westinghouse Electric & Manufacturing Company's ] labs.<ref name=Klooster>{{cite book |url=http://books.google.com/books?id=WKuG-VIwID8C&pg=PA305&lpg=PA305&dq=tesla+hired+by+westinghouse&source=bl&ots=KDI0aTz0EK&sig=oct2jnPyWkQ3qvUR-JmstK9F0FI&hl=en&sa=X&ei=jRwxUKK3LtS80QHjxoGYAg&sqi=2&ved=0CEEQ6AEwAw#v=onepage&q=tesla%20hired%20by%20westinghouse&f=false |title=John W. Klooster, Icons of Invention: The Makers of the Modern World from Gutenberg to Gates |page=305 |publisher=Books.google.com |author=Klooster, John W. |date=30 July 2009 |accessdate=10 September 2012}}</ref>


The investors showed little interest in Tesla's ideas for new types of ] motors and electrical transmission equipment. After the utility was up and running in 1886, they decided that the manufacturing side of the business was too competitive and opted to simply run an electric utility.{{sfn|Carlson|2013|p=75}} They formed a new utility company, abandoning Tesla's company and leaving the inventor penniless.{{sfn|Carlson|2013|p=75}} Tesla even lost control of the patents he had generated, since he had assigned them to the company in exchange for stock.{{sfn|Carlson|2013|p=75}} He had to work at various electrical repair jobs and as a ditch digger for $2 per day. Later in life Tesla recounted that part of 1886 as a time of hardship, writing "My high education in various branches of science, mechanics and literature seemed to me like a mockery".{{sfn|Carlson|2013|p=75}}{{efn|Account comes from a letter Tesla sent in 1938 on the occasion of receiving an award from the National Institute of Immigrant Welfare<ref>{{cite book | editor-first = John T. | editor-last = Ratzlaff | title = Tesla Said | publisher = Tesla Book Co. | location = Millbrae, California | page = 280 | year = 1984 | isbn = 0-914119-00-1 | url = https://archive.org/details/nikolateslajohnt.ratzlaffteslasaid }}</ref>}}
During that year, Tesla worked in Pittsburgh, helping to create an alternating current system to power the city's streetcars. He found the time there frustrating because of conflicts between him and the other Westinghouse engineers over how best to implement AC power. Between them, they settled on a 60-cycle AC current system Tesla proposed (to match the working frequency of Tesla's motor), although they soon found that, since Tesla's induction motor could only run at a constant speed, it would not work for street cars. They ended up using a DC ] instead.<ref>{{cite web |last=Harris |first=William |url=http://science.howstuffworks.com/nikola-tesla2.htm |title=William Harris, How did Nikola Tesla change the way we use energy? |page=3 |publisher=Science.howstuffworks.com |date=14 July 2008 |accessdate=10 September 2012}}</ref><ref name=Munson>{{cite book |title=From Edison to Enron: The Business of Power and What It Means for the Future of Electricity |publisher=Praeger |author=Munson, Richard |year=2005 |pages=24–42 |location=Westport, CT |isbn=978-0-275-98740-4}}</ref>


=== War of Currents === == AC and the induction motor ==
]
Tesla's alternating current work put him firmly on the "AC" side of the so-called "],"<ref name=Wolf>{{cite journal |title=War of the Currents&nbsp;– An Update |author=Wolf, Gene |journal=Transmission & Distribution World |date=April 2012 |quote=It was around the same time that George Westinghouse entered the battle. He believed in the new ac technology and struck a deal with Tesla to purchase his patents. The 'War of the Currents,' as historians call it, was under way.}}</ref> an electrical standards battle waged between Thomas Edison and George Westinghouse.<ref name=Nadis>{{cite book |title=Wonder Shows: Performing Science, Magic, and Religion in America |publisher=Rutgers University Press |author=Nadis, Fred |year=2005 |pages=60–64 |isbn=978-0-8135-3515-9}}</ref><ref name=McElroy>{{cite book |title=Energy: Perspectives, Problems, and Prospects |publisher=Oxford University Press |author=McElroy, Michael B. |year=2010 |location=New York |pages=271–273 |isbn=978-0-19-538611-0}}</ref> Tesla's patents, along with the others that Westinghouse's company had acquired or developed, allowed Westinghouse to build a rival AC system that could compete with Thomas Edison's DC system.<ref>The 100 Most Significant Events in American Business: An Encyclopedia By Quentin R. Skrabec Jr. pp. 86-87</ref>


In late 1886, Tesla met Alfred S. Brown, a ] superintendent, and New York attorney Charles Fletcher Peck.<ref>Charles Fletcher Peck of ] per {{Webarchive|url=https://web.archive.org/web/20201008142341/https://patents.google.com/patent/US381968A/en|date=8 October 2020}}</ref> The two men were experienced in setting up companies and promoting inventions and patents for financial gain.{{sfn|Carlson|2013|p=80}} Based on Tesla's new ideas for electrical equipment, including a ] idea,{{sfn|Carlson|2013|pp=76–78}} they agreed to back the inventor financially and handle his patents. Together they formed the Tesla Electric Company in April 1887, with an agreement that profits from generated patents would go {{frac|1|3}} to Tesla, {{frac|1|3}} to Peck and Brown, and {{frac|1|3}} to fund development.{{sfn|Carlson|2013|p=80}} They set up a laboratory for Tesla at 89 Liberty Street in Manhattan, where he worked on improving and developing new types of electric motors, generators, and other devices.
In 1893, George Westinghouse won the bid to electrify the 1893 ] in Chicago with alternating current, beating out a bid by Edison to electrify the fair with direct current. This ] devoted a building to electrical exhibits. It was a key event in the history of AC power, as Westinghouse demonstrated the safety, reliability, and efficiency of alternating current to the American public.<ref>America at the Fair:: Chicago's 1893 World's Columbian Exposition (Google eBook) Chaim M. Rosenberg Arcadia Publishing, 20 February 2008</ref><ref>{{cite book |url=http://books.google.com/books?id=F6cWRxU9go4C&pg=PR21&dq=westinghouse+World%27s+Columbian+Exposition&hl=en&sa=X&ei=RPv2T5mzG8mQ0QHFj7nqBg&ved=0CDgQ6AEwAQ#v=onepage&q=westinghouse%20World%27s%20Columbian%20Exposition&f=false |title=David J. Bertuca, Donald K. Hartman, Susan M. Neumeister, The World's Columbian Exposition: A Centennial Bibliographic Guide, p. xxi |publisher=Books.google.com |accessdate=10 September 2012}}</ref> At the Columbian Exposition, Tesla demonstrated a series of electrical effects previously performed throughout America and Europe,<ref name=Cheney />{{Rp|76}} included using high-voltage, high-frequency alternating current to light a wireless ].<ref name=Cheney />{{Rp|79}} An observer noted:


In 1887, Tesla developed an ] that ran on ] (AC), a power system format that was rapidly expanding in Europe and the United States because of its advantages in long-distance, ] transmission. The motor used ] current, which generated a ] to turn the motor (a principle that Tesla claimed to have conceived in 1882).<ref name="ReferenceB">{{cite book |title=Networks of Power: Electrification in Western Society, 1880–1930 |publisher=JHU Press |page=117 |url=https://books.google.com/books?id=g07Q9M4agp4C&pg=PA117 |isbn=978-0-8018-4614-4 |date=March 1993 |access-date=13 December 2015 |archive-date=23 March 2024 |archive-url=https://web.archive.org/web/20240323123125/https://books.google.com/books?id=g07Q9M4agp4C&pg=PA117#v=onepage&q&f=false |url-status=live }}</ref><ref>Thomas Parke Hughes, ''Networks of Power: Electrification in Western Society, 1880–1930'', pp. 115–118</ref><ref>{{cite book |url=https://books.google.com/books?id=1AsFdUxOwu8C&pg=PA204 |title=Robert Bud, Instruments of Science: An Historical Encyclopedia |page=204 |access-date=18 March 2013 |isbn=978-0-8153-1561-2 |last1=Ltd |first1=Nmsi Trading |last2=Institution |first2=Smithsonian |year=1998 |publisher=Taylor & Francis |archive-date=23 March 2024 |archive-url=https://web.archive.org/web/20240323123051/https://books.google.com/books?id=1AsFdUxOwu8C&pg=PA204#v=onepage&q&f=false |url-status=live }}</ref> This innovative electric motor, patented in May 1888, was a simple self-starting design that did not need a ], thus avoiding sparking and the high maintenance of constantly servicing and replacing mechanical brushes.{{sfn|Jonnes|2004|p=161}}<ref>Henry G. Prout, ''A Life of George Westinghouse'', p. 129</ref>
{{quote|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".<ref>{{cite book |title=Electricity at the Columbian Exposition; Including an Account of the Exhibits in the Electricity Building, the Power Plant in Machinery Hall |last=Barrett |first=John Patrick |year=1894 |isbn= |pages=268–269 |url=http://books.google.com/?id=CLtIAAAAMAAJ&printsec=frontcover#v=onepage&q&f=false |accessdate=29 November 2010}}</ref>}}


Along with getting the motor patented, Peck and Brown arranged to get the motor publicized, starting with independent testing to verify it was a functional improvement, followed by press releases sent to technical publications for articles to run concurrently with the issue of the patent.{{sfn|Carlson|2013|p=105-106}} Physicist ] (who tested the motor) and ''Electrical World'' magazine editor ] arranged for Tesla to demonstrate his AC motor on 16 May 1888 at the ].{{sfn|Carlson|2013|p=105-106}}<ref>{{cite book |url=https://books.google.com/books?id=8j5bJ5OkGpgC&pg=PA36 |first1=Fritz E. |last1=Froehlich |first2=Allen |last2=Kent |author-link2=Allen Kent |title=The Froehlich/Kent Encyclopedia of Telecommunications: Volume 17 |page=36 |access-date=10 September 2012 |isbn=978-0-8247-2915-8 |date=December 1998 |publisher=CRC Press |archive-date=23 March 2024 |archive-url=https://web.archive.org/web/20240323123231/https://books.google.com/books?id=8j5bJ5OkGpgC&pg=PA36#v=onepage&q&f=false |url-status=live }}</ref> Engineers working for the ] reported to ] that Tesla had a viable AC motor and related power system—something Westinghouse needed for the alternating current system he was already marketing. Westinghouse looked into getting a patent on a similar commutator-less, rotating magnetic field-based induction motor developed in 1885 and presented in a paper in March 1888 by Italian physicist ], but decided that Tesla's patent would probably control the market.{{sfn|Jonnes|2004|p=160–162}}{{sfn|Carlson|2013|pp=108–111}}
Tesla also explained the principles of a rotating magnetic field and induction motor by demonstrating how to make a copper egg stand on end using a device he constructed known as the '']''.<ref>{{cite web |title=Tesla's Egg of Columbus How Tesla Performed the Feat of Columbus Without Cracking the Egg |url=http://www.teslauniverse.com/nikola-tesla-article-teslas-egg-of-columbus |publisher=Tesla Universe |accessdate=5 July 2012}}</ref>


]) in an 1888 {{US patent|390721}}]]
By 1892 Edison's company was consolidated into the conglomerate ] by financier ] and the new company (by then switching over to an all AC system) was involved in take over attempts and patent battles with ]. Although a patent sharing agreement was signed between the two companies in 1896<ref>{{cite web|url=http://www.history.co.uk/biographies/j-p-morgan.html|quote=Agreement stayed in effect until 1911|first1= Quentin R.|last1= Skrabec|first2=George|last2= Westinghouse|title= Gentle Genius|page= 190|work=History}}</ref> Westinghouse was still cashed strapped from the financial warfare. To secure further loans Westinghouse was forced to revisit Tesla's AC patent, which bankers considered a financial strain on the company<ref>Thomas Parke Hughes, Networks of power: electrification in Western society, 1880–1930 (1983), p. 119</ref><ref>Hans Camenzind, Much Ado About Almost Nothing: Man's Encounter With the Electron, (2007), p. 107</ref> (at that point Westinghouse had paid out an estimated $200,000 in licenses and royalties to Tesla, Brown, and Peck<ref>{{harvnb|Seifer|2001|p=190}}</ref>). In 1897, Westinghouse explained his financial difficulties to Tesla in stark terms, saying that if things continue the way they were he would no longer be in control of Westinghouse Electric and Tesla would have to "deal with the bankers" to try to collect future royalties. Westinghouse convinced Tesla to release his company from the licensing agreement over Tesla's AC patents in exchange for Westinghouse Electric purchasing the patents for a ] payment of $216,000;<ref name=Cheney />{{Rp|73–74}} this provided Westinghouse a break from what, due to alternating current's rapid gain in popularity, had turned out to be an overly generous $2.50 per AC horsepower royalty.<ref name=Klooster />


In July 1888, Brown and Peck negotiated a licensing deal with George Westinghouse for Tesla's polyphase induction motor and transformer designs for $60,000 in cash and stock and a royalty of $2.50 per AC horsepower produced by each motor. Westinghouse also hired Tesla for one year for the large fee of $2,000 (${{Inflation|US|2000|1888|r=-2|fmt=c}} in today's dollars{{Inflation-fn|US}}) per month to be a consultant at the Westinghouse Electric & Manufacturing Company's ] labs.{{sfn|Klooster|2009|p=305}}
=== American citizenship ===
On 30 July 1891, at the age of 35, Tesla became a ] of the United States,<ref name=Tesla-Timeline-1891 /> and established his South ] laboratory, and later another at 46 E. ], in New York. He lit electric lamps wirelessly at both locations, demonstrating the potential of ].<ref>{{cite journal |last1=Krumme |first1=Katherine |year=2000 |title=Mark Twain and Nikola Tesla: Thunder and Lightning |publisher=University of California, Berkeley |url=http://web.archive.org/web/20120516065244/http://www.genevolution.net/documents/twain%20and%20tesla.pdf |format=PDF}}</ref> In the same year, he patented the ].<ref name=Uth>{{cite web |last=Uth |first=Robert |title=Tesla coil |date=12 December 2000 |work=Tesla: Master of Lightning |publisher=PBS.org |url=http://www.pbs.org/tesla/ins/lab_tescoil.html |accessdate=20 May 2008}}</ref>


During that year, Tesla worked in Pittsburgh, helping to create an alternating current system to power the city's streetcars. He found it a frustrating period because of conflicts with the other Westinghouse engineers over how best to implement AC power. Between them, they settled on a 60-cycle AC system that Tesla proposed (to match the working frequency of Tesla's motor), but they soon found that it would not work for streetcars, since Tesla's induction motor could run only at a constant speed. They ended up using a DC ] instead.<ref>{{cite web|last=Harris|first=William|url=https://science.howstuffworks.com/nikola-tesla.htm#pt2|title=William Harris, How did Nikola Tesla change the way we use energy?|page=3|publisher=Science.howstuffworks.com|date=14 July 2008|access-date=10 September 2012|archive-date=22 May 2019|archive-url=https://web.archive.org/web/20190522131016/https://science.howstuffworks.com/nikola-tesla2.htm#pt2|url-status=live}}</ref><ref name=Munson>{{cite book|title=From Edison to Enron: The Business of Power and What It Means for the Future of Electricity|publisher=Praeger|last=Munson |first=Richard|year=2005|pages=|location=Westport, CT|isbn=978-0-275-98740-4|url=https://archive.org/details/fromedisontoenro00muns_0/page/24}}</ref>
Tesla served as vice president of the ], the forerunner (along with the ]) of the modern-day ], from 1892 to 1894.<ref>{{cite web |title=Tesla's Connection to Columbia University * |url=http://www.teslasociety.com/columbia.pdf |publisher=Tesla Memorial Society of NY |accessdate=5 July 2012 |author=Kenneth L. Corum and James F. Corum, Ph.D.}}</ref>


=== X-ray experimentation === === Market turmoil ===
Tesla's demonstration of his induction motor and Westinghouse's subsequent licensing of the patent, both in 1888, came at the time of extreme competition between electric companies.<ref>Quentin R. Skrabec (2007). ''George Westinghouse: Gentle Genius'', Algora Publishing, pp. 119–121</ref><ref>Robert L. Bradley, Jr. (2011). ''Edison to Enron: Energy Markets and Political Strategies'', John Wiley & Sons, pp. 55–58</ref> The three big firms, Westinghouse, Edison, and ], were trying to grow in a capital-intensive business while financially undercutting each other. There was even a "]" propaganda campaign going on, with Edison Electric claiming their ] system was better and safer than the Westinghouse alternating current system and Thomson-Houston sometimes siding with Edison.<ref>Quentin R. Skrabec (2007). ''George Westinghouse: Gentle Genius'', Algora Publishing, pp. 118–120</ref>{{sfn|Seifer|1998|p=47}} Competing in this market meant Westinghouse would not have the cash or engineering resources to develop Tesla's motor and the related polyphase system right away.<ref name="gentlegenius">{{cite book|last1=Skrabec|first1=Quentin R.|title=George Westinghouse : gentle genius|date=2007|publisher=Algora Pub.|location=New York|isbn=978-0-87586-506-5}}</ref>
]


Two years after signing the Tesla contract, Westinghouse Electric was in trouble. The near collapse of ] in London triggered the ], causing investors to call in their loans to Westinghouse Electric.{{sfn|Carlson|2013|p=130}} The sudden cash shortage forced the company to refinance its debts. The new lenders demanded that Westinghouse cut back on what looked like excessive spending on acquisition of other companies, research, and patents, including the per motor royalty in the Tesla contract.{{sfn|Carlson|2013|p=131}}{{sfn|Jonnes|2004|p=29}} At that point, the Tesla induction motor had been unsuccessful and was stuck in development.<ref name="gentlegenius" />{{sfn|Carlson|2013|p=130}} Westinghouse was paying a $15,000-a-year guaranteed royalty<ref>Thomas Parke Hughes, ''Networks of Power: Electrification in Western Society, 1880–1930'' (1983), p. 119</ref> even though operating examples of the motor were rare and polyphase power systems needed to run it were even rarer.{{sfn|Jonnes|2004|p=161}}{{sfn|Carlson|2013|p=130}} In early 1891, George Westinghouse explained his financial difficulties to Tesla in stark terms, saying that, if he did not meet the demands of his lenders, he would no longer be in control of Westinghouse Electric and Tesla would have to "deal with the bankers" to try to collect future royalties.{{sfn|Jonnes|2004|p=228}} The advantages of having Westinghouse continue to champion the motor probably seemed obvious to Tesla and he agreed to release the company from the royalty payment clause in the contract.{{sfn|Jonnes|2004|p=228}}{{sfn|Carlson|2013|pp=130–131}} Six years later Westinghouse purchased Tesla's patent for a ] payment of $216,000 as part of a patent-sharing agreement signed with ] (a company created from the 1892 merger of Edison and Thomson-Houston).{{sfn|Cheney|2001|pp=48–49}}<ref>Christopher Cooper, ''The Truth About Tesla: The Myth of the Lone Genius in the History of Innovation'', Race Point Publishing. 2015, p. 109</ref><ref>''Electricity, a Popular Electrical Journal'', Volume 13, No. 4, 4 August 1897, Electricity Newspaper Company, pp. 50 {{Webarchive|url=https://web.archive.org/web/20230528024213/https://books.google.com/books?id=nNA9AQAAMAAJ&q=tesla+patent+1897+%22patent+pool%22&pg=PA50 |date=28 May 2023 }}</ref>
Starting in 1894, Tesla began investigating what he referred to as radiant energy of "invisible" kinds after he had noticed damaged film in his laboratory in previous experiments<ref>. Retrieved 26 August 2012</ref><ref>{{cite book |url=http://books.google.com/books?id=Fi18dCHfbLkC&pg=PT88&lpg=PT88&dq=tesla+x-rays+1887&source=bl&ots=UVw7tdb5bk&sig=hXULQfNzmjjtPVuemVrxWrlfGIo&hl=en&sa=X&ei=Bis2UJ7PA8Xi0QHKyIH4Aw&ved=0CDoQ6AEwAg#v=onepage&q=tesla%20x-rays%201887&f=false |title=P. K. Chadda, Hydroenergy and Its Energy Potential |publisher=Books.google.com |accessdate=10 September 2012}}</ref> (later identified as "''Roentgen rays''" or "]"). His early experiments were with ]s, a ] electrical discharge tube. Soon after, much of Tesla's early research—hundreds of invention models, plans, notes, laboratory data, tools, photographs, valued at $50,000—was lost in the 5th Avenue laboratory fire of March 1895. Tesla is quoted by '']'' as saying, "I am in too much grief to talk. What can I say?"<ref>{{cite web |title=Tesla Timeline |url=http://www.teslauniverse.com/nikola-tesla-timeline-1895-tesla-looses-fifth-ave-lab-to-fire |publisher=Tesla Universe |accessdate=4 July 2012}}</ref> Tesla may have inadvertently captured an X-ray image (predating ]'s December 1895 announcement of the discovery of x-rays by a few weeks) when he tried to photograph Mark Twain illuminated by a ], an earlier type of gas discharge tube. The only thing captured in the image was the metal locking screw on the camera lens.<ref name=Cheney />{{Rp|134}}


== New York laboratories ==
In March 1896, after hearing of ]'s discovery of X-ray and X-ray imaging (]),<ref>{{cite web |last=South |first=Nanette |url=http://anengineersaspect.blogspot.com/2011/07/nikola-tesla-radiography-experiments.html |title=Nikola Tesla&nbsp;– Radiography Experiments&nbsp;– Clips from the "The Constitution, Atlanta, Georgia, p. 9. Friday, 13 March 1896" |publisher=Anengineersaspect.blogspot.com |date=23 July 2011 |accessdate=10 September 2012}}</ref> Tesla proceeded to do his own experiments in X-ray imaging, developing a high energy single terminal ] of his own design that had no target electrode and that worked from the output of the Tesla Coil (the modern term for the phenomenon produced by this device is '']'' or ''braking radiation''). In his research, Tesla devised several experimental setups to produce X-rays. Tesla held that, with his circuits, the "instrument will&nbsp;... enable one to generate Roentgen rays of much greater power than obtainable with ordinary apparatus."<ref>N. Tesla, , in ''Proceedings of the American Electro-Therapeutic Association'', American Electro-Therapeutic Association. p.&nbsp;25.</ref>
] in Tesla's South Fifth Avenue laboratory, 1894]]


The money Tesla made from licensing his AC patents made him independently wealthy and gave him the time and funds to pursue his own interests.<ref>{{cite journal | url = https://teslauniverse.com/nikola-tesla/articles/nikola-tesla-scientific-savant | title = Nikola Tesla: Scientific Savant from the Tesla Universe Article Collection | first = James P. |last = Rybak | journal = ] | date = November 1999 | pages = 40–48 & 88 | access-date = 21 January 2017 | archive-date = 26 February 2019 | archive-url = https://web.archive.org/web/20190226121548/https://teslauniverse.com/nikola-tesla/articles/nikola-tesla-scientific-savant | url-status = live }}</ref> In 1889, Tesla moved out of the Liberty Street shop Peck and Brown had rented and for the next dozen years worked out of a series of workshop/laboratory spaces in ]. These included a lab at 175 ] (1889–1892), the fourth floor of 33–35 South ] (1892–1895), and sixth and seventh floors of 46 & 48 East ] (1895–1902).<ref>Carlson, W. Bernard (2013). ''Tesla: Inventor of the Electrical Age'', Princeton University Press, p. 218</ref><ref>{{cite web|url=https://teslaresearch.jimdo.com/labs-in-new-york-1889-1902/|title=Laboratories in New York (1889–1902)|website=Open Tesla Research|access-date=21 January 2017|archive-date=20 August 2018|archive-url=https://web.archive.org/web/20180820234947/https://teslaresearch.jimdo.com/labs-in-new-york-1889-1902/|url-status=live}}</ref> Tesla and his hired staff conducted some of his most significant work in these workshops.
Tesla noted the hazards of working with his circuit and single-node X-ray-producing devices. In his many notes on 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 by the ] generated in contact with the skin, and to a lesser extent, by ]. Tesla incorrectly believed that X-rays were longitudinal waves, such as those produced in ]. These plasma waves can occur in ]s.<ref>Griffiths, David J. ''Introduction to Electrodynamics'', ISBN 0-13-805326-X and Jackson, John D. ''Classical Electrodynamics'', ISBN 0-471-30932-X.</ref><ref>{{cite book |title=Transactions of the American Electro-therapeutic Association |last=Anonymous |year=1899 |isbn= |page=16 |url=http://books.google.com/?id=bUo7vYNkbKQC |accessdate=25 November 2010}}</ref>


=== Tesla coil ===
On 11 July 1934, the '']'' published an article on Tesla, in which he recalled an event that would occasionally take place while experimenting with his single-electrode vacuum tubes; a minute particle would break off the cathode, pass out of the tube, and physically strike him. "Tesla said he could feel a sharp stinging pain where it entered his body, and again at the place where it passed out." In comparing these particles with the bits of metal projected by his "electric gun," Tesla said, "The particles in the beam of force&nbsp;... will travel much faster than such particles ... and they will travel in concentrations."<ref name=Anderson>{{cite book |last=Anderson |first=Leland, |title=Nikola Tesla's teleforce & telegeodynamics proposals |year=1998 |publisher=21st Century Books |location=Breckenridge, Colo. |isbn=0-9636012-8-8}}</ref>
{{Main|Tesla coil}}


In the summer of 1889, Tesla traveled to the ] in Paris and learned of ]'s 1886–1888 experiments that proved the existence of ], including ]s.{{sfn|Carlson|2013|p=120}} In repeating and then expanding on these experiments Tesla tried powering a ] with a high speed ] he had been developing as part of an improved ] system but found that the high-frequency current overheated the iron core and melted the insulation between the primary and secondary windings in the coil. To fix this problem Tesla came up with his "oscillating transformer", with an air gap instead of insulating material between the primary and secondary windings and an iron core that could be moved to different positions in or out of the coil.{{sfn|Carlson|2013|p=122}} Later called the Tesla coil, it would be used to produce high-], low-], high ] ] electricity.<ref name="NMFL">{{cite web |title=Tesla coil |work=Museum of Electricity and Magnetism, Center for Learning |publisher=National High Magnetic Field Laboratory website, Florida State Univ. |date=2011 |url=https://nationalmaglab.org/education/magnet-academy/history-of-electricity-magnetism/museum/tesla-coil-1891 |access-date=12 September 2013 |archive-date=23 September 2015 |archive-url=https://web.archive.org/web/20150923174243/https://nationalmaglab.org/education/magnet-academy/history-of-electricity-magnetism/museum/tesla-coil-1891 |url-status=live }}</ref> He would use this ] in his later wireless power work.{{sfn|Carlson|2013|p=124}}<ref name="BurnettOperation">{{cite web
=== Radio ===
| last = Burnett
] demonstration during his 1891 lecture on high frequency and potential.]]
| first = Richie
| title = Operation of the Tesla Coil
| work = Richie's Tesla Coil Web Page
| publisher = Richard Burnett private website
| date = 2008
| url = http://www.richieburnett.co.uk/operation.html#operation
| access-date = 24 July 2015
| archive-date = 20 July 2015
| archive-url = https://web.archive.org/web/20150720104724/http://www.richieburnett.co.uk/operation.html#operation
| url-status = live
}}</ref>


=== Citizenship ===
Tesla's theories on the possibility of the transmission by radio waves go back as far as lectures and demonstrations in 1893 in ], Missouri, the ] in ], Pennsylvania, and the ].<ref name=Orton>{{cite book |last=Orton |first=John |title=The Story of Semiconductors |year=2004 |publisher=Oxford University Press |location=Oxford, England |page=53}}{{Subscription required|via=]}}</ref> Tesla's demonstrations and principles were written about widely through various media outlets.<ref name=Tesla-1892>{{cite book |title=Experiments with alternate currents of high potential and high frequency |last=Tesla |first=Nikola |year=1892 |isbn= |page=58 |url=http://books.google.com/books?id=kNhCQPbYIsgC&printsec=frontcover#v=onepage&q&f=false |accessdate=26 November 2010}}</ref> Many devices such as the Tesla Coil were used in the further development of radio.<ref name="books.google.com">{{cite book |url=http://books.google.co.uk/books?id=IyVFweSZu0cC |title=A Century of Innovation: Twenty Engineering Achievements That Transformed Our Lives |page=70 |publisher=Joseph Henry Press |year=2001}}</ref>
On 30 July 1891, aged 35, Tesla became a ] of the United States.<ref name="NYcourts">{{Cite web |url=https://www.fold3.com/image/20564444?ann=f3dc7880-a283-11dc-2973-11792d3d4a08 |title=Naturalization Record of Nikola Tesla, 30 July 1891 |access-date=24 October 2021 |archive-date=24 October 2021 |archive-url=https://web.archive.org/web/20211024010806/https://www.fold3.com/image/20564444?ann=f3dc7880-a283-11dc-2973-11792d3d4a08 |url-status=live }}, Naturalization Index, NYC Courts, referenced in Carlson (2013), ''Tesla: Inventor of the Electrical Age'', p. H-41</ref>{{sfn|Carlson|2013|p=138}} In the same year, he patented his Tesla coil.<ref name="Uth">{{cite web|last=Uth|first=Robert|title=Tesla coil|date=12 December 2000|work=Tesla: Master of Lightning|publisher=PBS.org|url=https://www.pbs.org/tesla/ins/lab_tescoil.html|access-date=20 May 2008|archive-date=5 September 2019|archive-url=https://web.archive.org/web/20190905184548/http://www.pbs.org/tesla/ins/lab_tescoil.html|url-status=live}}</ref>


=== Wireless lighting ===
{{double image|left|Tesla boat1.jpg|110||170|In 1898, Tesla demonstrated a radio-controlled boat ({{US patent|613,809}}&nbsp;—''Method of an Apparatus for Controlling Mechanism of Moving Vehicle or Vehicles'').}}


] via two long ]s (similar to ]) in his hands]]
Tesla's radio wave experiments in 1896 were conducted in Gerlach Hotel (later renamed The Radio Wave building), where he resided.<ref>{{cite web |title=The Beautiful New York City where Tesla spent 60 years of his life |url=http://www.teslasociety.com/beautifulnyc.htm |publisher=Tesla Society of NY |accessdate=17 September 2012}}</ref>


After 1890, Tesla experimented with transmitting power by inductive and capacitive coupling using high AC voltages generated with his Tesla coil.<ref name="Tesla1891">{{Cite book |url=http://www.tfcbooks.com/tesla/1891-05-20.htm |title=Experiments with Alternate Currents of Very High Frequency and Their Application to Methods of Artificial Illumination |first=Nikola |last=Tesla |publication-date=20 May 1891 |access-date=21 January 2017 |archive-date=6 March 2023 |archive-url=https://web.archive.org/web/20230306023235/http://www.tfcbooks.com/tesla/1891-05-20.htm |url-status=live }}, lecture delivered before the ], Columbia College, New York. Reprinted as a {{cite book |title = book of the same name by |publisher = Wildside Press |date = 2006 |url = https://books.google.com/books?id=94eH3rULPy4C |isbn = 0-8095-0162-7 |access-date = 21 January 2017 |archive-date = 23 March 2024 |archive-url = https://web.archive.org/web/20240323123047/https://books.google.com/books?id=94eH3rULPy4C |url-status = live }}</ref> He attempted to develop a wireless lighting system based on ] inductive and capacitive coupling and conducted a series of public demonstrations where he lit ]s and even incandescent light bulbs from across a stage.{{sfn|Carlson|2013|p=132}} He spent most of the decade working on variations of this new form of lighting with the help of various investors but none of the ventures succeeded in making a commercial product out of his findings.<ref>Christopher Cooper (2015). ''The Truth About Tesla: The Myth of the Lone Genius in the History of Innovation'', Race Point Publishing, pp. 143–144</ref>
In 1898, Tesla demonstrated a ] boat—which he dubbed "teleautomaton"—to the public during an electrical exhibition at ].<ref name=Jonnes /> The crowd that witnessed the demonstration made outrageous claims about the workings of the boat, such as magic, telepathy, and being piloted by a trained monkey hidden inside.<ref>Eger, Christopher (1 April 2007) "The Robot Boat of Nikola Tesla: The Beginnings of the UUV and remote control weapons"</ref> Tesla tried to sell his idea to the U.S. military as a type of radio-controlled ], but they showed little interest.<ref>{{cite book |url=http://books.google.com/books?id=6aStP3Du5cgC&pg=PT50&lpg=PT50&dq=tesla+radio+controlled+torpedo&source=bl&ots=kCZEi3Sewl&sig=9BodsLXXdagl2_dqi9CRWt6clbw&hl=en&sa=X&ei=lKw2UPTaIIiK0QGrloDIDg&sqi=2&ved=0CDIQ6AEwAQ#v=onepage&q=tesla%20radio%20controlled%20torpedo&f=false |title=P. W. Singer, Wired for War: The Robotics Revolution and Conflict in the Twenty-First Century&nbsp;– Robots Go To War |publisher=Books.google.com |accessdate=10 September 2012}}</ref> Remote ] remained a novelty until World War I and afterward, when a number of countries used it in ].<ref>Fitzsimons, Bernard, ed. "Fritz-X", in ''The Illustrated Encyclopedia of 20th Century Weapons and Warfare'' (London: Phoebus, 1978), Volume 10, p.1037.</ref> Tesla took the opportunity to further demonstrate "Teleautomatics" in an address to a meeting of the Commercial Club in ], whilst he was travelling to ], on 13 May 1899.<ref name="teslauniverse4">{{cite web |title=Tesla Timeline |url=http://www.teslauniverse.com/nikola-tesla-timeline-1856-birth-of-tesla |publisher=Tesla Universe |accessdate=20 May 2013}}</ref>


In 1893 at ], Missouri, the ] in ], Pennsylvania and the ], Tesla told onlookers that he was sure a system like his could eventually conduct "intelligible signals or perhaps even power to any distance without the use of wires" by conducting it through the Earth.{{sfn|Carlson|2013|pp=178–179}}<ref name="Orton">{{cite book |last=Orton |first=John |title=The Story of Semiconductors |year=2004 |publisher=Oxford University Press |location=Oxford, England |page=53}}</ref>
In 1900, Tesla was granted patents for a "system of transmitting electrical energy" and "an electrical transmitter." When ] made his famous first-ever transatlantic radio transmission in 1901, Tesla quipped that it was done with 17 Tesla patents. This was the beginning of years of patent battles over radio with Tesla's patents being upheld in 1903, followed by a reverse decision in favor of Marconi in 1904. In 1943, a ] decision restored the prior patents of Tesla, ], and ].<ref name="LQsxMxEUC page 3">{{cite book |url=http://books.google.com/books?id=c92LQsxMxEUC&pg=PA3&lpg=PA3&dq=British+Court+tesla+radio&source=bl&ots=9enh3iv6Ri&sig=_cZbUxJcBpahYAzA9esD9bb_Tj0&hl=en#v=onepage&q=British%20Court%20tesla%20radio&f=false |title=Jean-Michel Redouté, Michiel Steyaert, EMC of Analog Integrated Circuits |page=3 |publisher=Books.google.com |accessdate=18 March 2013}}</ref> The court declared that their decision had no bearing on Marconi's claim as the first to achieve radio transmission, just that since Marconi's claim to certain patents were questionable, he could not claim infringement on those same patents<ref>{{cite book |url=http://books.google.com/books?id=SdGaiV6iup0C&pg=PA3&lpg=PA3&dq=supreme+court+1943+radio+marconi&source=bl&ots=rKt8D5C3xg&sig=XuISBITcZzpFApoFE-IROq9qns0&hl=en#v=onepage&q=supreme%20court%201943%20radio%20marconi&f=false |title=Robert Sobot, Wireless Communication Electronics:Introduction to RF Circuits and Design Techniques |page=4 |publisher=Books.google.com |date=18 February 2012 |accessdate=18 March 2013}}</ref> (there are claims the high court was trying to nullify a World War I claim against the U.S. government by the Marconi Company via simply restoring Tesla's prior patent).<ref name="LQsxMxEUC page 3" />


Tesla served as a vice-president of the ] from 1892 to 1894, the forerunner of the modern-day ] (along with the ]).<ref>{{cite web|title=Tesla's Connection to Columbia University|url=http://www.teslasociety.com/columbia.pdf|publisher=Tesla Memorial Society of NY|access-date=5 July 2012|first1=Kenneth L.|last1=Corum|first2=James F.|last2=Corum|name-list-style=amp|archive-date=18 November 2017|archive-url=https://web.archive.org/web/20171118002803/http://www.teslasociety.com/columbia.pdf|url-status=live}}</ref>
=== Colorado Springs ===
{{See also|Magnifying transmitter|Colorado Springs Notes, 1899–1900}}
] picture (one of 68 Colorado Springs images created by of ''Century Magazine'' photographer Dickenson Alley) of Tesla sitting in his laboratory with his "]" generating millions of volts. The {{convert|7|m|adj=on}} long arcs were not part of the normal operation and were produced for effect by rapidly cycling the power switch<ref>W. Bernard Carlson, Tesla: Inventor of the Electrical Age, Princeton University Press - 2013, pages 290-301</ref>]]
]


=== {{anchor|The "Tesla Polyphase System"}}Polyphase system and the Columbian Exposition ===
On 17 May 1899, Tesla moved to ], where he would have room for his high-voltage, high-frequency experiments;<ref name="teslauniverse4" /> his lab was located near Foote Ave. and Kiowa St.<ref>According to the Tesla memorial marker in Memorial Park on Pikes Peak Ave.</ref> He chose this location because the polyphase alternating current power distribution system had been introduced there and he had associates who were willing to give him all the power he needed without charging for it.<ref>''Nikola Tesla On His Work With Alternating Currents and Their Application to Wireless Telegraphy, Telephony, and Transmission of Power'', Leland I. Anderson, 21st Century Books, 2002, p. 109, ISBN 1-893817-01-6.</ref> <!--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).--> Upon his arrival, he told reporters that he was conducting ] experiments, transmitting signals from ] to Paris.{{Citation needed|date=September 2012}} The 1978 book '']'' contains descriptions of Tesla's experiments.
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]


By the beginning of 1893, Westinghouse engineer ] and then ] had made progress on an efficient version of Tesla's induction motor. Lamme found a way to make the ] it would need compatible with older single-phase AC and DC systems by developing a ].{{sfn|Carlson|2013|p=166}} Westinghouse Electric now had a way to provide electricity to all potential customers and started branding their polyphase AC system as the "Tesla Polyphase System". They believed that Tesla's patents gave them ] over other polyphase AC systems.{{sfn|Carlson|2013|p=167}}
On 15 June 1899, Tesla performed his first experiments at his Colorado Springs lab; he recorded his initial spark length at five inches long, but very thick and noisy.<ref name="teslauniverse4" />


Westinghouse Electric asked Tesla to participate in the 1893 ] in Chicago where the company had a large space in the "Electricity Building" devoted to electrical exhibits. Westinghouse Electric won the bid to light the Exposition with alternating current and it was a key event in the history of AC power, as the company demonstrated to the American public the safety, reliability, and efficiency of an alternating current system that was polyphase and could also supply the other AC and DC exhibits at the fair.<ref>{{cite book |first=Richard |last=Moran |title=Executioner's Current: Thomas Edison, George Westinghouse, and the Invention of the Electric Chair |publisher=Knopf Doubleday Publishing Group |date=2007 |page=222}}</ref><ref>{{cite book |url=https://books.google.com/books?id=-ErxIGp3QN0C |title=America at the Fair: Chicago's 1893 World's Columbian Exposition |first=Chaim M. |last=Rosenberg |publisher=Arcadia Publishing |date=20 February 2008 |isbn=978-0-7385-2521-1 |access-date=3 November 2021 |archive-date=23 March 2024 |archive-url=https://web.archive.org/web/20240323123130/https://books.google.com/books?id=-ErxIGp3QN0C |url-status=live }}</ref><ref>{{cite book|url=https://books.google.com/books?id=F6cWRxU9go4C&pg=PR21|title=The World's Columbian Exposition: A Centennial Bibliographic Guide|first1=David J.|last1=Bertuca|first2=Donald K.|last2=Hartman|first3=Susan M.|last3=Neumeister|year=1996|name-list-style=amp|pages=xxi|publisher=Bloomsbury Academic|isbn=978-0-313-26644-7|access-date=10 September 2012|archive-date=23 March 2024|archive-url=https://web.archive.org/web/20240323123640/https://books.google.com/books?id=F6cWRxU9go4C&pg=PR21|url-status=live}}</ref>
Tesla investigated ], observing lightning signals via his receivers. Tesla stated that he observed ]s during this time.<ref>Corum, K. L., J. F. Corum, "''Nikola Tesla, Lightning Observations, and Stationary Waves''." 1994.</ref> The great distances and the nature of what Tesla was detecting from lightning storms confirmed his belief that the earth had a ].<ref>Marc Seifer (1998). ''Wizard: The Life and Times of Nikola Tesla''. p. 217</ref><ref>Some Tesla historians speculate that what Tesla was actually observing was an atmospheric phenomenon called the ] where resonances occur in the ] formed by the space between the surface of the earth and the conductive ].(Margaret Cheney, Robert Uth, Jim Glenn, Tesla, Master of Lightning, p. 168), (), (Corum, J. F., K.L. Corum, ''Nikola Tesla and the Diameter of the Earth: A Discussion of One of the Many Modes of Operation of the Wardenclyffe Tower'', 1996, p. 13)</ref>


A special exhibit space was set up to display various forms and models of Tesla's induction motor. The rotating magnetic field that drove them was explained through a series of demonstrations including an '']'' that used the two-phase coil found in an induction motor to spin a copper egg making it stand on end.<ref>Hugo Gernsback, "Tesla's Egg of Columbus, How Tesla Performed the Feat of Columbus Without Cracking the Egg" Electrical Experimenter, 19 March 1919, p. 774 {{Webarchive|url=https://web.archive.org/web/20200327222415/http://www.teslacollection.com/tesla_articles/1919/electrical_experimenter/h_gernsback/the_tesla_egg_of_columbus|date=27 March 2020}}</ref>
He produced artificial ] (with discharges consisting of millions of volts and up to 135&nbsp;feet long).<ref>Gillispie, Charles Coulston, "''Dictionary of Scientific Biography'';" ''Tesla, Nikola''. Charles Scribner's Sons, New York.</ref> Thunder from the released energy was heard 15 miles away in ]. People walking along the street observed sparks jumping between their feet and the ground. Sparks sprang from water line taps when touched. Light bulbs within 100 feet of the lab glowed even when turned off. Horses in a livery stable bolted from their stalls after receiving shocks through their metal shoes. Butterflies were electrified, swirling in circles with blue halos of ] around their wings.<ref>{{harvnb|Childress|1993}}</ref>


Tesla visited the fair for a week during its six-month run to attend the ] and put on a series of demonstrations at the Westinghouse exhibit.{{sfn|Seifer|2001|p=120}}<ref>Thomas Commerford Martin, The Inventions, Researches and Writings of Nikola Tesla: With Special Reference to His Work in Polyphase Currents and High Potential Lighting, Electrical Engineer – 1894, Chapter XLII, page 485 </ref> A specially darkened room had been set up where Tesla showed his wireless lighting system, using a demonstration he had previously performed throughout America and Europe;{{sfn|Cheney|2001|p=76}} these included using high-voltage, high-frequency alternating current to light wireless ]s.{{sfn|Cheney|2001|p=79}}
While experimenting, Tesla inadvertently faulted a power station generator, causing a ]. In August 1917, Tesla explained what had happened in ''The Electrical Experimenter'': "As an example of what has been done with several hundred kilowatts of high frequency energy liberated, it was found that the dynamos in a power house six miles away were repeatedly burned out, due to the powerful high frequency currents set up in them, and which caused heavy sparks to jump through the windings and destroy the insulation!"<ref>{{cite journal |last=SECOR |first=H. WINFIELD |title=TESLA'S VIEWS ON ELECTRICITY AND THE WAR |journal=The Electrical Experimenter |date=August 1917 |url=http://www.tfcbooks.com/tesla/1917-08-00.htm |accessdate=9 September 2012}}</ref>
] with a transmitter illuminates a light near the bottom of the picture.<ref name="Tesla">{{cite book
| last1 = Tesla
| first1 = Nikola
| title = Nikola Tesla on His Work with Alternating Currents and Their Application to Wireless Telegraphy, Telephony, and Transmission of Power: An Extended Interview
| publisher = 21st Century Books
| date = 2002
| location =
| pages = 96-97
| language =
| url = http://books.google.com/books?id=KRg9HWakBmQC&pg=PA96#v=onepage&q&f=false
| doi =
| id =
| isbn = 1893817016
}}</ref> Tesla did not disclose how far away the transmitter was.<ref name="Tesla" /><ref>W. Bernard Carlson, Tesla: Inventor of the Electrical Age, Princeton University Press - 2013, pages 290-301</ref>]]


An observer noted:
During his time at his lab, Tesla observed unusual signals from his receiver which he concluded may be communications from another planet. He mentioned them in a letter to reporter ] at the ] on 8 December 1899<ref>Daniel Blair Stewart (1999). ''Tesla: The Modern Sorcerer'', Frog Book. p. 372</ref> and in a December 1900 letter about possible discoveries in the new century to the ] where he referred to messages "from another world" that read "1... 2... 3...".<ref>W. Bernard Carlson (2013). ''Tesla: Inventor of the Electrical Age''. Princeton University Press., p. 315</ref><ref>Marc Seifer (1998). ''Wizard: The Life And Times Of Nikola Tesla''. Citadel. pp. 220–223</ref> Reporters treated it as a sensational story and jumped to the conclusion Tesla was hearing signals from ].<ref>W. Bernard Carlson (2013). ''Tesla: Inventor of the Electrical Age''. Princeton University Press. p. 315</ref> He expanded on the signals he heard in a 9 February 1901 Collier's Weekly article "Talking With Planets" where he said it had not been immediately apparent to him that he was hearing "intelligently controlled signals" and that the signals could come from Mars, ], or other planets.<ref>Marc Seifer, Wizard (1998). ''The Life And Times Of Nikola Tesla''. Citadel, pp. 220–222</ref> It has been hypothesized that he may have intercepted Marconi's European experiments in July 1899—Marconi may have transmitted the letter S (dot/dot/dot) in a naval demonstration, the same three impulses that Tesla hinted at hearing in Colorado<ref>Marc Seifer, Wizard (1998). ''The Life And Times Of Nikola Tesla''. Citadel. pp. 220–223</ref>—or signals from another experimenter in wireless transmission.<ref name="seifer2006">{{rs|date=July 2014}}{{cite web |last=Seifer |first=Marc |title=Nikola Tesla: The Lost Wizard |url=http://teslatech.info/ttmagazine/v4n1/seifer.htm |publisher=ExtraOrdinary Technology (Volume 4, Issue 1; Jan/Feb/March 2006) |accessdate=14 July 2012}}</ref>


{{blockquote|Within the room were 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".<ref>{{cite book |title=Electricity at the Columbian Exposition; Including an Account of the Exhibits in the Electricity Building, the Power Plant in Machinery Hall |publisher=R. R. Donnelley |last=Barrett |first=John Patrick |year=1894 |pages=–269 |url=https://archive.org/details/electricityatco00barrgoog |access-date=29 November 2010}}</ref>}}
In 1899, ] invested $100,000 for Tesla to further develop and produce a new lighting system. Instead, Tesla used the money to fund his Colorado Springs experiments.<ref>{{cite web |title=Tesla Timeline |url=http://www.teslauniverse.com/nikola-tesla-timeline-1912-john-jacob-astor-dies |publisher=Tesla Universe |accessdate=10 September 2012}}</ref>


=== Steam-powered oscillating generator ===
On 7 January 1900, Tesla left ].{{Citation needed|date=September 2012}} His lab was torn down in 1904, and its contents were sold two years later to satisfy a debt.<ref name=denver-eye>{{cite web |url=http://www.thedenvereye.com/nikola-tesla-in-colorado-springs/ |title=Nikola Tesla in Colorado Springs |publisher=The Denver Eye |accessdate=17 June 2014}}</ref><ref name=ES-060322>{{cite news |url=http://chroniclingamerica.loc.gov/lccn/sn88085421/1906-03-22/ed-1/seq-2/#date1=1836&index=0&rows=20&words=COLORADO+SPRINGS+Tesla&searchType=basic&sequence=0&state=&date2=1922&proxtext=tesla+colorado+springs&y=0&x=0&dateFilterType=yearRange&page=1 |title=Tesla Plant at Auction |date=22 March 1906 |agency=Evening Statesman |accessdate=17 June 2014 |location=Walla Walla, WA}}</ref>
{{Main|Tesla's oscillator}}


During his presentation at the International Electrical Congress in the Columbian Exposition Agriculture Hall, Tesla introduced his ] that he patented that year, something he thought was a better way to generate alternating current.{{sfn|Carlson|2013|p=182}} Steam was forced into the oscillator and rushed out through a series of ports, pushing a piston up and down that was attached to an armature. The magnetic armature vibrated up and down at high speed, producing an alternating ]. This ] alternating electric current in the wire coils located adjacent. It did away with the complicated parts of a steam engine/generator, but never caught on as a feasible engineering solution to generate electricity.{{sfn|Carlson|2013|pp=181–185}}<ref>Reciprocating Engine, {{US patent|514169}}, 6 February 1894.</ref>
The Colorado experiments had prepared Tesla for the establishment of the trans-Atlantic wireless telecommunications facility known as Wardenclyffe near Shoreham, Long Island.<ref name="seifer542">{{harvnb|Seifer|2001|p=542}}</ref> <!-- Tesla was granted {{US patent|685,012}} for the means of increasing the intensity of electrical oscillations. The ] classification system currently assigns this patent to the primary Class 178/43 ("telegraphy/space induction"), although the other applicable classes include 505/825 ("low temperature superconductivity-related apparatus"). -->


=== Consulting on Niagara ===
== Wardenclyffe years (1900–1917) ==
{{Main|Wardenclyffe Tower}}
{{Tall image|Tesla Ready For Business 1901.jpg|225|150|''Tesla Ready for Business''&nbsp;– 7 August 1901 New-York tribune article|right}}
]
]


In 1893, ], who headed the ] ], sought Tesla's opinion on what system would be best to transmit power generated at the falls. Over several years, there had been a series of proposals and open competitions on how best to do it. Among the systems proposed by several US and European companies were two-phase and three-phase AC, high-voltage DC, and compressed air. Adams asked Tesla for information about the current state of all the competing systems. Tesla advised Adams that a two-phased system would be the most reliable and that there was a Westinghouse system to light incandescent bulbs using two-phase alternating current. The company awarded a contract to Westinghouse Electric for building a two-phase AC generating system at the Niagara Falls, based on Tesla's advice and Westinghouse's demonstration at the Columbian Exposition. At the same time, a further contract was awarded to General Electric to build the AC distribution system.{{sfn|Carlson|2013|pp=167–173}}
In 1900, with $150,000 (${{Inflation|US|150000|1900|r=-2|fmt=c}} in today's dollars{{Inflation-fn|US}}; 51% from ]), Tesla began planning the ] facility.<ref name="broad1">{{cite news |last=Broad |first=William J |title=A Battle to Preserve a Visionary's Bold Failure |url=http://www.nytimes.com/2009/05/05/science/05tesla.html |accessdate=20 May 2013 |newspaper=The New York Times |date=4 May 2009}}</ref>


=== The Nikola Tesla Company ===
Tesla later approached Morgan to ask for more funds to build a more powerful transmitter. When asked where all the money had gone, Tesla responded by saying that he was affected by the ], which he (Morgan) had caused. Morgan was shocked by the reminder of his part in the stock market crash and by Tesla's breach of contract by asking for more funds. Tesla wrote another plea to Morgan, but it was also fruitless. Morgan still owed Tesla money on the original agreement, and Tesla had been facing foreclosure even before construction of the tower began.<ref name="seifer2006" />
In 1895, Edward Dean Adams, impressed with what he saw when he toured Tesla's lab, agreed to help found the Nikola Tesla Company, set up to fund, develop, and market a variety of previous Tesla patents and inventions as well as new ones. Alfred Brown signed on, bringing along patents developed under Peck and Brown. The board was filled out with William Birch Rankine and Charles F. Coaney.{{sfn|Carlson|2013|pp=205–206}} It found few investors since the mid-1890s were a tough time financially, and the wireless lighting and oscillators patents it was set up to market never panned out. The company handled Tesla's patents for decades to come.


=== Lab fire ===
In December 1901, Marconi successfully transmitted the letter S from England to ], terminating Tesla's relationship with Morgan.{{synthesis-inline|date=June 2014}} Over the next five years, Tesla wrote over 50 letters to Morgan, pleading for and demanding additional funding to complete the construction of Wardenclyffe. Tesla continued the project for another nine months. The tower was erected to its full {{convert|187|feet|meters}}.<ref name="seifer2006" /> In July 1903, Tesla wrote to Morgan that in addition to wireless communication, Wardenclyffe would be capable of wireless transmission of electric power.<ref name="broad1" /> On 14 October 1904, Morgan finally replied through his secretary, stating, "It will be impossible for to do anything in the matter," after Tesla had written to Morgan when the financier was meeting with the ] in an attempt to appeal to his Christian spirit.<ref name="seifer2006" />


In the early morning hours of 13 March 1895, the South Fifth Avenue building that housed Tesla's lab caught fire. It started in the basement of the building and was so intense Tesla's 4th-floor lab burned and collapsed into the second floor. The fire not only set back Tesla's ongoing projects, but it also destroyed a collection of early notes and research material, models, and demonstration pieces, including many that had been exhibited at the 1893 Worlds Colombian Exposition. Tesla told '']'' "I am in too much grief to talk. What can I say?".<ref>Mr. Tesla's Great Loss, All of the Electrician’s Valuable Instruments Burned, WORK OF HALF A LIFETIME GONE, New York Times, 14 March 1895 (archived at {{Webarchive|url=https://web.archive.org/web/20220628160738/https://teslauniverse.com/nikola-tesla/articles/mr-teslas-great-loss |date=28 June 2022 }})</ref> After the fire Tesla moved to 46 & 48 East Houston Street and rebuilt his lab on the 6th and 7th floors.
In June 1902, Tesla's lab operations were moved to Wardenclyffe from Houston Street.<ref name="broad1" />


=== X-ray experimentation ===
On his 50th birthday in 1906, Tesla demonstrated his {{convert|200|hp|kW|abbr=off}} 16,000&nbsp;rpm ]. During 1910–1911 at the ''Waterside Power Station'' in New York, several of his bladeless turbine engines were tested at 100–5,000&nbsp;hp.<ref>{{cite web |title=Timeline |url=http://www.teslasociety.org/timeline.html |publisher=Tesla Memorial Society of NY |accessdate=3 July 2012}}</ref>
]


Starting in 1894, Tesla began investigating what he referred to as ] of "invisible" kinds after he had noticed damaged film in his laboratory in previous experiments<ref>{{cite book|last1=Tesla|first1=Nikola|title=X-ray vision: Nikola Tesla on Roentgen rays|date=2007|publisher=Wiilder Publications|location=Radford, VA|isbn=978-1-934451-92-2|edition=1st}}</ref> (later identified as "Roentgen rays" or "]"). His early experiments were with ]s, a ] electrical discharge tube. Tesla may have inadvertently captured an X-ray image—predating, by a few weeks, ]'s December 1895 announcement of the discovery of X-rays—when he tried to photograph Mark Twain illuminated by a ], an earlier type of gas discharge tube. The only thing captured in the image was the metal locking screw on the camera lens.{{sfn|Cheney|2001|p=134}}
Tesla invented a steam-powered mechanical oscillator—]. While experimenting with mechanical oscillators at his Houston Street lab, Tesla allegedly generated a resonance of several buildings. As the speed grew, it is said that the machine oscillated at the resonance frequency of his own building and, belatedly realizing the danger, he was forced to use a sledge hammer to terminate the experiment, just as the police arrived.<ref name=ONeill />{{Rp|162–164}} In February 1912, an article—"Nikola Tesla, Dreamer" by Allan L. Benson—was published in ''World Today'', in which an artist's illustration appears showing the entire earth cracking in half with the caption, "Tesla claims that in a few weeks he could set the earth's crust into such a state of vibration that it would rise and fall hundreds of feet and practically destroy civilization. A continuation of this process would, he says, eventually split the earth in two."<ref name=Anderson />


In March 1896, after hearing of Röntgen's discovery of X-ray and X-ray imaging (]),<ref>RADIOGRAPHY – EXPERIMENTS MADE BY NIKOLA TESLA – Shoulder of a Man Taken Through His Clothing—Chalky Deposits Infallibly Detected, The Constitution, Atlanta, Georgia, Friday 13, March 1896, p. 9 {{Webarchive|url=https://web.archive.org/web/20131004213023/http://anengineersaspect.blogspot.com/2011/07/nikola-tesla-radiography-experiments.html |date=4 October 2013 }}</ref> Tesla proceeded to do his own experiments in X-ray imaging, developing a high-energy single-terminal ] of his own design that had no target electrode and that worked from the output of the Tesla coil (the modern term for the phenomenon produced by this device is '']'' or ''braking radiation''). In his research, Tesla devised several experimental setups to produce X-rays. Tesla held that, with his circuits, the "instrument will&nbsp;... enable one to generate Roentgen rays of much greater power than obtainable with ordinary apparatus".<ref>{{cite book |first=Nikola |last=Tesla |url=http://www.tfcbooks.com/tesla/1898-11-17.htm |chapter=High Frequency Oscillators for Electro-Therapeutic and Other Purposes |title=Proceedings of the American Electro-Therapeutic Association |publisher=American Electro-Therapeutic Association |page=25 |date=17 November 1898 |access-date=27 January 2009 |archive-date=1 January 2016 |archive-url=https://web.archive.org/web/20160101011808/http://www.tfcbooks.com/tesla/1898-11-17.htm |url-status=live }}</ref>
Tesla theorized that the application of electricity to the brain enhanced intelligence. In 1912, he crafted "a plan to make dull students bright by saturating them unconsciously with electricity," wiring the walls of a schoolroom and, "saturating with infinitesimal electric waves vibrating at high frequency. The whole room will thus, Mr. Tesla claims, be converted into a health-giving and stimulating electromagnetic field or 'bath.'"<ref name="Gilliams">{{cite web |last1=Gilliams |first1=E. Leslie |title=Tesla's Plan of Electrically Treating Schoolchildren |url=http://www.teslacollection.com/tesla_articles/1912/popular_electricity_magazine/e_leslie_gilliams/tesla_s_plan_of_electrically_treating_school_children |website=teslacollection.com/ |publisher=Popular Electricity Magazine (1912) |accessdate=19 August 2014}}</ref> The plan was, at least provisionally approved by then superintendent of New York City schools, William H. Maxwell.<ref name="Gilliams" />


Tesla noted the hazards of working with his circuit and single-node X-ray-producing devices. In his many notes on 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 by the ] generated in contact with the skin, and to a lesser extent, by ]. Tesla incorrectly believed that X-rays were longitudinal waves, such as those produced in ]. These plasma waves can occur in ]s.<ref>Griffiths, David J. ''Introduction to Electrodynamics'', {{ISBN|0-13-805326-X}} and Jackson, John D. ''Classical Electrodynamics'', {{ISBN|0-471-30932-X}}.</ref><ref>{{cite book |title=Transactions of the American Electro-therapeutic Association |publisher=American Electrotherapeutic Association |year=1899 |page=16 |url=https://books.google.com/books?id=bUo7vYNkbKQC |access-date=25 November 2010 |archive-date=23 March 2024 |archive-url=https://web.archive.org/web/20240323123806/https://books.google.com/books?id=bUo7vYNkbKQC |url-status=live }}</ref>
Before ], Tesla sought overseas investors. After the war started, Tesla lost the funding he was receiving from his patents in European countries. Eventually, he sold Wardenclyffe for $20,000 (${{Inflation|US|20000|1914|r=-2|fmt=c}} in today's dollars{{Inflation-fn|US}}).<ref name="broad1" /> 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 ].{{Citation needed|date=June 2012}}


On 11 July 1934, the '']'' published an article on Tesla, in which he recalled an event that occasionally took place while experimenting with his single-electrode vacuum tubes. A minute particle would break off the cathode, pass out of the tube, and physically strike him:<ref name=Anderson>{{cite book |last=Anderson |first=Leland |title=Nikola Tesla's teleforce & telegeodynamics proposals |year=1998 |publisher=21st Century Books |location=Breckenridge, Colo. |isbn=0-9636012-8-8}}</ref>
In the August 1917 edition of the magazine ] Tesla postulated that electricity could be used to locate submarines via using the reflection of an "electric ray" of "tremendous frequency," with the signal being viewed on a fluorescent screen (a system that has been noted to have a superficial resemblance to modern ]).<ref>Margaret Cheney, Robert Uth, Jim Glenn, Tesla, Master of Lightning, pp. 128–129</ref> Tesla was incorrect in his assumption that high frequency radio waves would penetrate water<ref>{{cite web|url=http://books.google.com/books?id=W1JAeg1PiWIC&pg=PA154&dq=tesla+radar+detect+submarines+feasible&hl=en&sa=X&ei=2pFVU42ePIfesATW3oC4Ag&ved=0CDoQ6AEwAQ#v=onepage&q=tesla%20radar%20detect%20submarines%20feasible&f=false|title=Lewis Coe (2006). ''Wireless Radio: A History''. McFarland. p. 154|publisher=}}</ref> but ], who helped develop France's first radar system in the 1930s, noted in 1953 that Tesla's general speculation that a very strong high frequency signal would be needed was correct stating "''(Tesla) was prophesying or dreaming, since he had at his disposal no means of carrying them out, but one must add that if he was dreaming, at least he was dreaming correctly.''"<ref name=Cheney />{{Rp|266}}<ref>Margaret Cheney, Robert Uth, Jim Glenn, Tesla, Master of Lightning, p. 129</ref>
<blockquote>
Tesla said he could feel a sharp stinging pain where it entered his body, and again at the place where it passed out. In comparing these particles with the bits of metal projected by his "electric gun", Tesla said, "The particles in the beam of force&nbsp;... will travel much faster than such particles&nbsp;... and they will travel in concentrations".
</blockquote>


== Nobel Prize rumors == === Radio remote control ===
On 6 November 1915, a ] news agency report from London had the 1915 ] awarded to Thomas Edison and Nikola Tesla; however, on 15 November, a Reuters story from Stockholm stated the prize that year was being awarded to Sir William Henry Bragg and William Lawrence Bragg "for their services in the analysis of crystal structure by means of X-rays."<ref name=Cheney />{{Rp|245}}<ref>{{cite web |title=The Nobel Prize in Physics 1915 |url=http://www.nobelprize.org/nobel_prizes/physics/laureates/1915/ |publisher=nobelprize.org |accessdate=29 July 2012}}</ref><ref>{{harvnb|Cheney|Uth|Glenn|1999|p=120}}</ref> There were unsubstantiated rumors at the time that Tesla and/or Edison had refused the prize.<ref name=Cheney />{{Rp|245}} The Nobel Foundation said, "Any rumor that a person has not been given a Nobel Prize because he has made known his intention to refuse the reward is ridiculous"; a recipient could only decline a Nobel Prize after he is announced a winner.<ref name=Cheney />{{Rp|245}}


]
There have been subsequent claims by Tesla biographers that Edison and Tesla were the original recipients and that neither was given the award because of their animosity toward each other; 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; that both rejected any possibility of sharing it; and even that a wealthy Edison refused it to keep Tesla from getting the $20,000 prize money.<ref name=Cheney />{{Rp|245}}<ref name="Seifer 2001 7" /><ref>{{cite book |title=Nikola Tesla Research |last=Research |first=Health |publisher= |isbn=0-7873-0404-2 |page=9 |url=http://books.google.com/?id=N0gD7HxMfsUC&printsec=frontcover#v=onepage&q&f=false |accessdate=28 November 2010 |date=September 1996}}</ref>


In 1898, Tesla demonstrated a boat that used a ]-based ]—which he dubbed "telautomaton"—to the public during an electrical exhibition at ].{{sfn|Jonnes|2004}} Tesla tried to sell his idea to the US military as a type of radio-controlled ], but they showed little interest.<ref>{{cite book |url=https://books.google.com/books?id=6aStP3Du5cgC&pg=PT50 |first=P. W. |last=Singer |title=Wired for War: The Robotics Revolution and Conflict in the Twenty-first Century |date=2009 |publisher=Penguin |isbn=978-1-4406-8597-2 |via=Google Books |access-date=10 September 2012 |archive-date=23 March 2024 |archive-url=https://web.archive.org/web/20240323123553/https://books.google.com/books?id=6aStP3Du5cgC&pg=PT50#v=onepage&q&f=false |url-status=live }}</ref> Remote ] remained a novelty until World War I and afterward, when a number of countries used it in ].<ref>Fitzsimons, Bernard, ed. "Fritz-X", in ''The Illustrated Encyclopedia of 20th Century Weapons and Warfare'' (London: Phoebus, 1978), Volume 10, p.1037.</ref> Tesla took the opportunity to further demonstrate "Teleautomatics" in an address to a meeting of the Commercial Club in Chicago, while he was traveling to ], on 13 May 1899.
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 of 38 possible bids in 1937).<ref>{{harvnb|Seifer|2001|pp=378–380}}</ref>


== Later years (1918–1943) == == Wireless power ==
In 1928, Tesla received his last patent, {{US patent|1,655,114}}, for a ] capable of taking off vertically (] aircraft) and then be "''gradually tilted through manipulation of the elevator devices''" in flight until it was flying like a conventional plane.<ref>{{cite web |last=Tesla |first=Nikola |title=TESLA PATENT 1,655,114 APPARATUS FOR AERIAL TRANSPORTATION. |url=http://www.teslauniverse.com/nikola-tesla-patents-1,655,114-aerial-transportation |publisher=UNITED STATES PATENT OFFICE. |accessdate=20 July 2012}}</ref> Tesla thought the plane would sell for less than $1,000.<ref name=Cheney />{{Rp|251}} Although the aircraft was probably impractical, it may be the earliest known design for what became the ]/tilt-wing concept as well as the earliest proposal for the use of turbine engines in rotor aircraft.<ref>{{cite web |url=http://www.airspacemag.com/history-of-flight/OldandOdd-AS06.html |title=A.J.S. RAYL Air & Space magazine, September 2006, reprint at History of Flight |publisher=airspacemag.com |accessdate=10 September 2012}}</ref>{{synthesis-inline|date=June 2014}}


{{Further|Wireless power transfer#Tesla}}
Starting in 1934, the Westinghouse Electric & Manufacturing Company began paying Tesla $125 per month as well as paying his rent at the Hotel New Yorker, expenses the Company would pay for the rest of Tesla's life. Accounts on how this came about vary. Several sources say Westinghouse was worried about potential bad publicity surrounding the impoverished conditions their former star inventor was living under.<ref name=Jonnes />{{Rp|365}}<ref>{{harvnb|Cheney|Uth|Glenn|1999|p=149}}</ref><ref name="Seifer435">{{harvnb|Seifer|2001|p=435}}</ref> It has been described as being couched in the form of a "consulting fee" to get around Tesla's aversion to accept charity, or by one biographer (Marc Seifer), as a type of unspecified settlement.<ref name="Seifer435" />


]
In 1935, in an annual birthday celebration interview, Tesla announced a method of transmitting mechanical energy with minimal loss over any terrestrial distance, a related new means of communication, and a method of accurately determining the location of underground mineral deposits.<ref name=Anderson />


From the 1890s through 1906, Tesla spent a great deal of his time and fortune on a series of projects trying to develop ]. It was an expansion of his idea of using coils to transmit power that he had been demonstrating in wireless lighting. He saw this as not only a way to transmit large amounts of power around the world but also, as he had pointed out in his earlier lectures, a way to transmit worldwide communications.
In the fall of 1937, after midnight one night, Tesla left the Hotel New Yorker to make his regular commute to the cathedral and the library to feed the pigeons. While crossing a street a couple of blocks from the hotel, Tesla was unable to dodge a moving taxicab and was thrown heavily to the ground. Tesla's back was severely wrenched and three of his ribs were broken in the accident (the full extent of his injuries will never be known; Tesla refused to consult a doctor—an almost lifelong custom). Tesla didn't raise any question as to who was at fault and refused medical aid, only asking be taken to his hotel via cab. Tesla was bedridden for some months and was unable to continue feeding pigeons from his window; soon, they failed to come. In the spring of 1938, Tesla was able to get up. He at once resumed the pigeon-feeding walks on a much more limited scale, but frequently had a messenger act for him.<ref name=ONeill />


At the time Tesla was formulating his ideas, there was no feasible way to wirelessly transmit communication signals over long distances, let alone large amounts of power. Tesla had studied radio waves early on, and came to the conclusion that part of the existing study on them, by Hertz, was incorrect.{{sfn|Carlson|2013|p=127}}<ref name="earlyradiohistory.us">{{cite web|url=https://earlyradiohistory.us/tesla.htm|title=Nikola Tesla: The Guy Who DIDN'T "Invent Radio" | first = Thomas H. | last = White | date = 1 November 2012 |website=earlyradiohistory.us|access-date=20 February 2018|archive-date=15 November 2019|archive-url=https://web.archive.org/web/20191115150200/http://earlyradiohistory.us/tesla.htm|url-status=live}}</ref>{{efn|Tesla's own experiments led him to erroneously believe Hertz had misidentified a form of conduction instead of a new form of electromagnetic radiation, an incorrect assumption that Tesla held for a couple of decades.<ref name="earlyradiohistory.us"/>{{sfn|Carlson|2013|pp=127–128}}}} Also, this new form of radiation was widely considered at the time to be a short-distance phenomenon that seemed to die out in less than a mile.<ref>Brian Regal, Radio: The Life Story of a Technology, p. 22</ref> Tesla noted that, even if theories on radio waves were true, they were totally worthless for his intended purposes since this form of "invisible light" would diminish over a distance just like any other radiation and would travel in straight lines right out into space, becoming "hopelessly lost".{{sfn|Carlson|2013|p=209}}
=== Directed-energy weapon ===
{{Main|Teleforce}}


By the mid-1890s, Tesla was working on the idea that he might be able to conduct electricity long distance through the Earth or the atmosphere, and began working on experiments to test this idea including setting up a large resonance transformer ] in his East Houston Street lab.<ref name="My Inventions"><u>My Inventions: The Autobiography of Nikola Tesla</u>, Hart Brothers, 1982, Ch. 5, {{ISBN|0-910077-00-2}}, originally appeared in '']'' magazine in 1919</ref><ref>"Tesla on Electricity Without Wires," <u>Electrical Engineer</u> – N.Y., 8 January 1896, p. 52. (Refers to letter by Tesla in the ''New York Herald'', 31 December 1895.)</ref><ref>''Mining & Scientific Press'', "Electrical Progress" Nikola Tesla Is Credited With Statement", 11 April 1896</ref> Seeming to borrow from a common idea at the time that the Earth's atmosphere was conductive,{{sfn|Seifer|2001|p=107}}{{sfn|Carlson|2013|p=45}} he proposed a system composed of balloons suspending, transmitting, and receiving, electrodes in the air above {{convert|30,000|feet}} in altitude, where he thought the lower pressure would allow him to send high voltages (millions of volts) long distances.
Later in life, Tesla made claims concerning a "]" weapon after studying the ].<ref>{{cite news |title=Tesla's Ray |work=Time |date=23 July 1934}}</ref><ref name="seifer1">{{cite web |last=Seifer |first=Marc |title=Tesla's "Death Ray" Machine |url=http://www.bibliotecapleyades.net/tesla/esp_tesla_2.htm |publisher=bibliotecapleyades.net |accessdate=4 July 2012}}</ref> The press called it a "peace ray" or ].<ref>{{cite news |title=Tesla, at 78, Bares New 'Death-Beam' |work=The New York Times |date=11 July 1934 |url=http://select.nytimes.com/gst/abstract.html?res=FB0817FD3E5B107A93C3A8178CD85F408385F9}}</ref><ref>{{cite news |title=Tesla Invents Peace Ray |work=New York Sun |date=10 July 1934}}</ref> Tesla described the weapon as being able to be used against ground-based infantry or for antiaircraft purposes.


=== Colorado Springs ===
Tesla gives the following description concerning the ]'s operation: {{quote| 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.<ref>{{cite news |title=Beam to Kill Army at 200 Miles, Tesla's Claim on 78th Birthday |work=The New York Times |date=11 July 1934}}</ref><ref>{{cite news |title='Death Ray' for Planes |work=The New York Times |date=22 September 1940}}</ref>}}
{{See also|Tesla Experimental Station|Magnifying transmitter|Colorado Springs Notes, 1899–1900}}
]


To further study the conductive nature of low-pressure air, Tesla set up an ] at high altitude in Colorado Springs during 1899.{{sfn|Cheney|Uth|Glenn|1999|p=92}}<ref>{{cite web|url=https://www.pbs.org/tesla/ll/ll_colspr.html|title=PBS: Tesla – Master of Lightning: Colorado Springs|website=]|access-date=6 September 2017|archive-date=7 July 2017|archive-url=https://web.archive.org/web/20170707120257/http://www.pbs.org/tesla/ll/ll_colspr.html|url-status=live}}</ref>{{sfn|Carlson|2013|p=264}}<ref name="Wireless Telegraphy 2002, p. 109">''Nikola Tesla On His Work With Alternating Currents and Their Application to Wireless Telegraphy, Telephony, and Transmission of Power'', Leland I. Anderson, 21st Century Books, 2002, p. 109, {{ISBN|1-893817-01-6}}.</ref> <!--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).--> There he could safely operate much larger coils than in the cramped confines of his New York lab, and an associate had made an arrangement for the El Paso Electric Light Company to supply alternating current free of charge.<ref name="Wireless Telegraphy 2002, p. 109" /> To fund his experiments, he convinced ] to invest $100,000 (${{Inflation|US|100000|1899|r=-2|fmt=c}} in today's dollars{{Inflation-fn|US}}) to become a majority shareholder in the Nikola Tesla Company. Astor thought he was primarily investing in the new wireless lighting system. Instead, Tesla used the money to fund his Colorado Springs experiments.{{sfn|Carlson|2013|pp=255–259}} Upon his arrival, he told reporters that he planned to conduct ] experiments, transmitting signals from ] to Paris.{{sfn|Cheney|2001|p=173}}
In total, the components and methods included:
* An apparatus for producing manifestations of energy in free air instead of in a ] as in the past.
* A mechanism for generating tremendous electrical force.
* 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.<ref>{{cite news |title=Death-Ray Machine Described |work=New York Sun |date=11 July 1934}}</ref><ref name=Liberty-1935>{{cite web |url=http://www.pbs.org/tesla/res/res_art11.html |title=A Machine to End War |publisher=] |date=9 February 1935 |accessdate=18 June 2014 |author=Tesla, Nikola}}</ref><ref name=Liberty-cover>{{cite web |url=http://www.magazineart.org/main.php/v/massweeklies/liberty/Liberty+1935-02-09.jpg.html |title=Cover of the February 9, 1935 issue of ''Liberty'' |publisher=MagazineArt.org |accessdate=18 June 2014}}</ref>


] picture of Tesla sitting next to his "]" generating millions of volts. The {{convert|7|m|adj=on}} long arcs were not part of the normal operation, but only produced for effect by rapidly cycling the power switch.{{sfn|Carlson|2013|pp=290–301}}]]
Tesla claimed to have worked on plans for a ] from the early 1900s until his death.<!-- Following refs cover 1920–1934 --><ref> UNITED STATES PATENT OFFICE Patent No. 1,329,559</ref><ref name="NYTTes1934">{{cite news |title=TESLA, AT 78, BARES NEW 'DEATH-BEAM' |url=http://select.nytimes.com/gst/abstract.html?res=FB0817FD3E5B107A93C3A8178CD85F408385F9 |accessdate=29 June 2012 |newspaper=The New York Times |date=11 July 1934}} </ref>


There, he conducted experiments with a large coil operating in the megavolts range, producing artificial lightning (and thunder) consisting of millions of volts and discharges of up to {{convert|135|ft|m|0}} in length,<ref>Gillispie, Charles Coulston, "''Dictionary of Scientific Biography'';" ''Tesla, Nikola''. Charles Scribner's Sons, New York.</ref> and, at one point, inadvertently burned out the generator in El Paso, causing a power outage.<ref>{{cite journal |last=SECOR |first=H. WINFIELD |title=TESLA'S VIEWS ON ELECTRICITY AND THE WAR |journal=The Electrical Experimenter |date=August 1917 |url=http://www.tfcbooks.com/tesla/1917-08-00.htm |access-date=9 September 2012 |archive-date=10 February 2011 |archive-url=https://web.archive.org/web/20110210071635/http://tfcbooks.com/tesla/1917-08-00.htm |url-status=live }}</ref> The observations he made of the electronic noise of lightning strikes led him to (incorrectly) conclude{{sfn|Carlson|2013|p=301}}{{sfn|Cooper|2015|p=165}} that he could use the entire globe of the Earth to conduct electrical energy.
In 1937, at a luncheon in his honor concerning the death ray, Tesla stated, "But it is not an experiment&nbsp;... I have built, demonstrated and used it. Only a little time will pass before I can give it to the world." His records indicate that the device is based on a narrow stream of small ] pellets that are accelerated via high voltage (by means akin to his ]).<ref name="seifer1" />


During his time at his laboratory, Tesla observed unusual signals from his receiver which he speculated to be communications from another planet. He mentioned them in a letter to a reporter in December 1899<ref>Daniel Blair Stewart (1999). ''Tesla: The Modern Sorcerer'', Frog Book. p. 372</ref> and to the ] in December 1900.{{sfn|Carlson|2013|p=315}}{{sfn|Seifer|1998|pp=220–223}} Reporters treated it as a sensational story and jumped to the conclusion Tesla was hearing signals from ].{{sfn|Carlson|2013|p=315}} He expanded on the signals he heard in a 9 February 1901 ''Collier's Weekly'' article entitled "Talking With Planets", where he said it had not been immediately apparent to him that he was hearing "intelligently controlled signals" and that the signals could have come from Mars, ], or other planets.{{sfn|Seifer|1998|pp=220–223}} It has been hypothesized that he may have intercepted ]'s European experiments in July 1899—Marconi may have transmitted the letter S (dot/dot/dot) in a naval demonstration, the same three impulses that Tesla hinted at hearing in Colorado{{sfn|Seifer|1998|pp=220–223}}—or signals from another experimenter in wireless transmission.<ref name="seifer2006">{{cite web |last=Seifer |first=Marc |title=Nikola Tesla: The Lost Wizard |url=http://teslatech.info/ttmagazine/v4n1/seifer.htm |publisher=ExtraOrdinary Technology (Volume 4, Issue 1; Jan/Feb/March 2006) |access-date=14 July 2012 |archive-date=25 September 2015 |archive-url=https://web.archive.org/web/20150925090553/http://teslatech.info/ttmagazine/v4n1/seifer.htm |url-status=live }}</ref>{{unreliable source?|date=July 2014}}
During the same year, Tesla wrote a treatise, ''The Art of Projecting Concentrated Non-dispersive Energy through the Natural Media'',<ref>Tesla, Nikola, '', Circa 16 May 1935.</ref> concerning ] weapons.<ref name="Seifer454">{{harvnb|Seifer|2001|p=454}}</ref> Tesla published the document in an attempt to expound on the technical description of a "] that would put an end to all war." This treatise is currently in the ] archive in ]. 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 non-dispersive particle streams (through ] repulsion).<ref name="Seifer454" /> Tesla tried to interest the ],<ref>"Aerial Defense 'Death-Beam' Offered to U.S. By Tesla" 12 July 1940</ref> the United Kingdom, the Soviet Union, and Yugoslavia in the device.<ref>{{cite web |last=Seifer |first=Marc J. |title=Tesla's "death ray" machine |url=http://www.bibliotecapleyades.net/tesla/esp_tesla_2.htm |accessdate=5 September 2012}}</ref>


Tesla had an agreement with the editor of '']'' to produce an article on his findings. The magazine sent a photographer to Colorado to photograph the work being done there. The article, titled "The Problem of Increasing Human Energy", appeared in the June 1900 edition of the magazine. He explained the superiority of the wireless system he envisioned but the article was more of a lengthy philosophical treatise than an understandable scientific description of his work,<ref>{{Cite web|url=http://www.teslamemorialsociety.org/info/Research%20of%20Nikola%20Tesla%20in%20Long%20Island%20Laboratory.htm|title=Research of Nikola Tesla in Long Island Laboratory|access-date=26 January 2017|archive-date=6 May 2016|archive-url=https://web.archive.org/web/20160506115345/http://www.teslamemorialsociety.org/info/Research%20of%20Nikola%20Tesla%20in%20Long%20Island%20Laboratory.htm|url-status=live}}</ref> illustrated with what were to become iconic images of Tesla and his Colorado Springs experiments.
During the period in which the negotiations were being carried on, Tesla said that efforts had been made to steal the invention. His room had been entered and his papers had been scrutinized, but the thieves, or spies, left empty-handed. He said that there was no danger that his invention could be stolen, for he had at no time committed any part of it to paper. The blueprint for the teleforce weapon was all in his mind.<ref>{{cite news |last1=O'Neill |first1=John J. |url=http://www.pbs.org/tesla/res/res_art12.html |title=Tesla Tries To Prevent World War II (unpublished Chapter 34 of Prodigal Genius) |work=PBS}}</ref>


== Death == === Wardenclyffe ===
{{Main|Wardenclyffe Tower}}
], Nikola Tesla Museum, Belgrade.]]
]


Tesla made the rounds in New York trying to find investors for what he thought would be a viable system of wireless transmission, wining and dining them at the ]'s Palm Garden (the hotel where he was living at the time), ], and ].<ref name="teslascience.org">{{cite web|url=http://www.teslascience.org/pages/dream.htm|title=Tesla Wardenclyffe Project Update – An Introduction to the Issues|website=www.teslascience.org|date=22 June 2023|access-date=26 January 2017|archive-date=21 January 2017|archive-url=https://web.archive.org/web/20170121115706/http://www.teslascience.org/pages/dream.htm|url-status=live}}</ref> In March 1901, he obtained $150,000 (${{Inflation|US|150000|1900|r=-2|fmt=c}} in today's dollars{{Inflation-fn|US}}) from ] in return for a 51% share of any generated wireless patents, and began planning the ] facility to be built in ], {{convert|100|mi|km|0}} east of the city on the North Shore of Long Island.<ref name="broad1">{{cite news |last=Broad |first=William J |title=A Battle to Preserve a Visionary's Bold Failure |url=https://www.nytimes.com/2009/05/05/science/05tesla.html |access-date=20 May 2013 |newspaper=The New York Times |date=4 May 2009 |archive-date=25 July 2018 |archive-url=https://web.archive.org/web/20180725111710/https://www.nytimes.com/2009/05/05/science/05tesla.html |url-status=live }}</ref>
On 7 January 1943, Tesla, 86, died alone in room 3327 of the ]. His body was later found by maid Alice Monaghan after she had entered Tesla's room, ignoring the "do not disturb" sign that Tesla had placed on his door two days earlier. Assistant medical examiner H.W. Wembly examined the body and ruled that the cause of death had been ].<ref name=Tesla-Timeline>{{cite web |title=Tesla Timeline |url=http://www.teslauniverse.com/nikola-tesla-timeline-1943-tesla-dies-at-86 |publisher=Tesla Universe |accessdate=18 July 2012}}</ref> Tesla's remains were taken to the Frank E. Campbell Funeral Home at Madison Ave. and 81st St. A long-time friend and supporter of Tesla, ], commissioned a sculptor to create a death mask, now displayed in the ].<ref name=Tesla-Timeline />


By July 1901, Tesla had expanded his plans to build a more powerful transmitter to leap ahead of ]'s radio-based system, which Tesla thought was a copy of his own.{{sfn|Carlson|2013|p=315}} He approached Morgan to ask for more money to build the larger system, but Morgan refused to supply any further funds.<ref name="seifer2006"/>{{unreliable source?|date=July 2014}} In December 1901, Marconi successfully transmitted the letter S from England to ], defeating Tesla in the race to be first to complete such a transmission. A month after Marconi's success, Tesla tried to get Morgan to back an even larger plan to transmit messages and power by controlling "vibrations throughout the globe".{{sfn|Carlson|2013|p=315}} Over the next five years, Tesla wrote more than 50 letters to Morgan, pleading for and demanding additional funding to complete the construction of Wardenclyffe. Tesla continued the project for another nine months into 1902. The tower was erected to its full height of {{convert|187|ft|m|0}}.<ref name="seifer2006" />{{unreliable source?|date=July 2014}} In June 1902, Tesla moved his lab operations from Houston Street to Wardenclyffe.<ref name="broad1" />
Two days later, the FBI ordered the ] to seize Tesla's belongings,<ref name=Tesla-Timeline /> even though Tesla was an American citizen.<ref name=Tesla-Timeline-1891>{{cite web |title=Tesla Timeline |url=http://www.teslauniverse.com/nikola-tesla-timeline-1891-tesla-granted-citizenship |work=July, 30th: Tesla's American Citizenship Tesla becomes an American citizen. |publisher=Tesla Universe |accessdate=11 July 2012}}</ref> Tesla's entire estate from the Hotel New Yorker and other New York City hotels was transported to the Manhattan Storage and Warehouse Company under Office of Alien Property (OAP) seal.<ref name=Tesla-Timeline /> ], a professor at ] and well-known electrical engineer serving as a technical aide to the ], was called in to analyze the Tesla items in OAP custody.<ref name=Tesla-Timeline /> After a three-day investigation, Trump's report concluded that there was nothing that would constitute a hazard in unfriendly hands, stating: {{quote| thoughts and efforts during at least the past 15 years were primarily of a speculative, philosophical, and somewhat promotional character often concerned with the production and wireless transmission of power; but did not include new, sound, workable principles or methods for realizing such results.<ref name="autogeneratedll">{{cite web |title=The Missing Papers |url=http://www.pbs.org/tesla/ll/ll_mispapers.html |publisher=PBS |accessdate=5 July 2012}}</ref>}} In a box purported to contain a part of Tesla's "death ray," Trump found a 45-year-old ].<ref>{{harvnb|Childress|1993|p=249}}</ref>


Investors on ] were putting their money into Marconi's system, and some in the press began turning against Tesla's project, claiming it was a hoax.<ref>Malanowski, Gregory, <u>The Race for Wireless</u>, AuthorHouse, p. 35</ref> The project came to a halt in 1905, and in 1906, the financial problems and other events may have led to what Tesla biographer ] suspects was a nervous breakdown on Tesla's part.<ref>{{cite book|first=David Hatcher|last= Childress|date=1993|isbn=978-0-932813-19-0|title= The Fantastic Inventions of Nikola Tesla|page= 255|publisher= Adventures Unlimited}}</ref> Tesla mortgaged the Wardenclyffe property to cover his debts at the Waldorf-Astoria, which eventually amounted to $20,000 (${{Inflation|US|20000|1914|r=-2|fmt=c}} in today's dollars{{Inflation-fn|US}}).<ref>{{cite book|url=https://books.google.com/books?id=KRg9HWakBmQC&q=tesla+1908+Wardenclyffe+foreclosed&pg=PA185|title=Nikola Tesla on His Work with Alternating Currents and Their Application to Wireless Telegraphy, Telephony, and Transmission of Power: An Extended Interview|first=Nikola|last=Tesla|date=8 December 2017|publisher=21st Century Books|via=Google Books|isbn=978-1-893817-01-2|access-date=18 November 2020|archive-date=23 March 2024|archive-url=https://web.archive.org/web/20240323123554/https://books.google.com/books?id=KRg9HWakBmQC&q=tesla+1908+Wardenclyffe+foreclosed&pg=PA185#v=snippet&q=tesla%201908%20Wardenclyffe%20foreclosed&f=false|url-status=live}}</ref> He lost the property in foreclosure in 1915, and in 1917 the Tower was demolished by the new owner to make the land a more viable real estate asset.
On 10 January 1943, New York City mayor ] read a eulogy written by Slovene-American author ] live over the ] radio while violin pieces "Ave Maria" and "]" were played in the background.<ref name=Tesla-Timeline /> On 12 January 2,000 people attended a state funeral for Tesla at the ]. After the funeral, Tesla's body was taken to the ] in Ardsley, New York, where it was later cremated. The following day, a second service was conducted by prominent priests in the Trinity Chapel (today's Serbian Orthodox Cathedral of Saint Sava) in New York City.<ref name=Tesla-Timeline />


=== Estate === == Later years ==
In 1952, following pressure from Tesla's nephew, Sava Kosanović, Tesla's entire estate was shipped to Belgrade in 80 trunks marked N.T.<ref name="teslauniverse4" /> In 1957, Kosanović secretary Charlotte Muzar transported Tesla's ashes from the United States to Belgrade.<ref name="teslauniverse4" /> The ashes are displayed in a gold-plated sphere on a marble pedestal in the ].<ref>{{cite web |title=Urn with Tesla's ashes |url=http://www.tesla-museum.org/meni_en/muzej/3.htm |publisher=Tesla Museum |accessdate=16 September 2012}}</ref>


After Wardenclyffe closed, Tesla continued to write to Morgan; after "the great man" died, Tesla wrote to Morgan's son Jack, trying to get further funding for the project. In 1906, Tesla opened offices at 165 Broadway in Manhattan, trying to raise further funds by developing and marketing his patents. He went on to have offices at the ] from 1910 to 1914; rented for a few months at the ], moving out because he could not afford the rent; and then to office space at 8 West 40th Street from 1915 to 1925. After moving to 8 West 40th Street, he was effectively bankrupt. Most of his patents had run out and he was having trouble with the new inventions he was trying to develop.{{sfn|Carlson|2013|pp=373–375}}
Despite having sold his AC electricity patents, Tesla died impoverished and in debt.<ref name=autogenerated13>{{cite news |title=Tesla No Money Wizard; Swamped By Debt, He Vows |url=http://www.google.com/imgres?um=1&hl=en&sa=N&biw=1280&bih=615&tbm=isch&tbnid=N8TRLgMqLpvKWM:&imgrefurl=http://www.teslauniverse.com/nikola-tesla-timeline-1916-tesla-declares-bankruptcy&docid=3WV4RK2_S_tCZM&imgurl=http://www.teslauniverse.com/img/timeline/entries/bankrupt.jpg&w=203&h=171&ei=54_JT8rTMOy70AG1pKSPAQ&zoom=1&iact=rc&dur=264&sig=112142546359786702237&page=1&tbnh=131&tbnw=161&start=0&ndsp=10&ved=1t:429,r:0,s:0,i:75&tx=60&ty=51 |accessdate=2 June 2012 |newspaper=NewYorkWorld |date=18 March 1916}}</ref><ref name=autogenerated14>{{cite news |last=Michaels |first=Daniel |title=Long-Dead Inventor Nikola Tesla Is Electrifying Hip Techies |url=http://online.wsj.com/article/SB10001424052748704362004575000841720318942.html |publisher=TheWallStreetJournal |accessdate=2 June 2012}}</ref><ref name=autogenerated15>{{cite news |title=Among Technophiles, Tesla In and Edison Out |url=http://www.foxnews.com/scitech/2010/01/14/long-dead-inventor-nikola-tesla-electrifying-hip-techies/ |publisher=Fox News Channel |accessdate=2 June 2012 |date=14 January 2010}}</ref><ref name=autogenerated12>{{cite news |last=Frum |first=Larry |title=Backers raise cash for Tesla museum honoring 'cult hero' |url=http://articles.cnn.com/2012-08-21/tech/tech_innovation_tesla-museum-campaign_1_tesla-motors-elon-musk-nikola-tesla |publisher=CNN |accessdate=13 September 2012 |date=22 August 2012}}</ref>


== Patents == === Bladeless turbine ===
{{Main|List of Nikola Tesla patents}} {{Main|Tesla turbine}}
]
]


On his 50th birthday, in 1906, Tesla demonstrated a {{convert|200|hp|kW|abbr=off}} 16,000&nbsp;rpm ]. During 1910–1911, at the ] in New York, several of his bladeless turbine engines were tested at 100–5,000&nbsp;hp.{{sfn|Carlson|2013|p=371}} Tesla worked with several companies including from 1919 to 1922 in ], for ].{{sfn|Seifer|2001|p=398}}{{sfn|Carlson|2013|p=373}} He spent most of his time trying to perfect the Tesla turbine with Hans Dahlstrand, the head engineer at the company, but engineering difficulties meant it was never made into a practical device.{{sfn|O'Neill|1944}}{{page needed|date=May 2024}} Tesla did license the idea to a precision instrument company and it found use in the form of luxury car ]s and other instruments.{{sfn|Cheney|Uth|Glenn|1999|p=115}}
Tesla obtained around 300 patents worldwide for his inventions.<ref name="sarboh">{{cite web |url=http://www.tesla-symp06.org/papers/Tesla-Symp06_Sarboh.pdf |title=Nikola Tesla's Patents |first=Snežana |last=Šarboh |date=18–20 October 2006 |work=Sixth International Symposium Nikola Tesla |location=Belgrade, Serbia |page=6 |format=PDF |archiveurl=http://web.archive.org/web/20071030134331/http://www.tesla-symp06.org/papers/Tesla-Symp06_Sarboh.pdf |archivedate=30 October 2007 |accessdate=8 October 2010 |ref=sarbo}}</ref> Some of Tesla's patents are not accounted for, and various sources have discovered some that have lain hidden in patent archives. There are a minimum of 278 patents<ref name="sarboh" /> issued to Tesla in 26 countries that have been accounted for. Many of Tesla's patents were in the United States, ], and ], but many other patents were approved in countries around the globe.<ref name=Cheney />{{Rp|62}} Many inventions developed by Tesla were not put into patent protection.


== Personal life == === Wireless lawsuits ===
{{specific|section|date=June 2014}}
Tesla worked every day from 9:00{{nbsp}}a.m until 6:00{{nbsp}}p.m. or later, with dinner from exactly 8:10 p.m., at ] restaurant and later the ]. Tesla would telephone his dinner order to the headwaiter, who also could be the only one to serve him. "The meal was required to be ready at eight o'clock&nbsp;... He dined alone, except on the rare occasions when he would give a dinner to a group to meet his social obligations. Tesla would then resume his work, often until 3:00{{nbsp}}a.m."<ref name=ONeill />{{Rp|283, 286}}


When ] broke out, the British cut the transatlantic telegraph cable linking the US to ] in order to control the flow of information between the two countries. They also tried to shut off German wireless communication to and from the US by having the US Marconi Company sue the German radio company ] for patent infringement.{{sfn|Carlson|2013|p=377}} Telefunken brought in the physicists ] and ] for their defense, and hired Tesla as a witness for two years for $1,000 a month. The case stalled and then went moot when the US entered the war against Germany in 1917.{{sfn|Carlson|2013|p=377}}{{sfn|Seifer|2001|p=373}}
For exercise, Tesla walked between 8 to 10 miles per day. He squished his toes one hundred times for each foot every night, saying that it stimulated his brain cells.<ref name=autogenerated11>{{harvnb|Seifer|2001|p=413}}</ref>


In 1915, Tesla attempted to sue the ] for infringement of his wireless tuning patents. Marconi's initial radio patent had been awarded in the US in 1897, but his 1900 patent submission covering improvements to radio transmission had been rejected several times, before it was finally approved in 1904, on the grounds that it infringed on other existing patents including two 1897 Tesla wireless power tuning patents.<ref name="earlyradiohistory.us" /><ref>Howard B. Rockman, Intellectual Property Law for Engineers and Scientists, John Wiley & Sons – 2004, p. 198.</ref><ref>{{Cite web|url=https://supreme.justia.com/cases/federal/us/320/1/|title=Marconi Wireless Tel. Co. v. United States, 320 U.S. 1 (1943)|website=Justia Law|access-date=29 January 2017|archive-date=25 June 2017|archive-url=https://web.archive.org/web/20170625130248/https://supreme.justia.com/cases/federal/us/320/1/|url-status=live}}</ref> Tesla's 1915 case went nowhere,{{sfn|Carlson|2013|p=377-378}} but in a related case, where the Marconi Company tried to sue the US government over WWI patent infringements, a ] 1943 decision restored the prior patents of ], ], and Tesla.<ref name="LQsxMxEUC page 3">{{cite book |url=https://books.google.com/books?id=c92LQsxMxEUC&q=British+Court+tesla+radio&pg=PA3 |title=Jean-Michel Redouté, Michiel Steyaert, EMC of Analog Integrated Circuits |page=3 |access-date=18 March 2013 |isbn=978-90-481-3230-0 |last1=Redouté |first1=Jean-Michel |last2=Steyaert |first2=Michiel |date=10 October 2009 |publisher=Springer |archive-date=23 March 2024 |archive-url=https://web.archive.org/web/20240323123811/https://books.google.com/books?id=c92LQsxMxEUC&q=British+Court+tesla+radio&pg=PA3#v=snippet&q=British%20Court%20tesla%20radio&f=false |url-status=live }}</ref> The court declared that their decision had no bearing on Marconi's claim as the first to achieve radio transmission, just that since Marconi's claim to certain patented improvements were questionable, the company could not claim infringement on those same patents.<ref name="earlyradiohistory.us" /><ref>{{cite book |url=https://books.google.com/books?id=SdGaiV6iup0C&q=supreme+court+1943+radio+marconi&pg=PA3 |title=Robert Sobot, Wireless Communication Electronics:Introduction to RF Circuits and Design Techniques |page=4 |date=18 February 2012 |access-date=18 March 2013 |isbn=978-1-4614-1116-1 |last1=Sobot |first1=Robert |publisher=Springer |archive-date=23 March 2024 |archive-url=https://web.archive.org/web/20240323123556/https://books.google.com/books?id=SdGaiV6iup0C&q=supreme+court+1943+radio+marconi&pg=PA3#v=snippet&q=supreme%20court%201943%20radio%20marconi&f=false |url-status=live }}</ref>
In an interview with newspaper editor ], Tesla said that he did not believe in telepathy, stating, "Suppose I made up my mind to murder you," he said, "In a second you would know it. Now, isn't that wonderful? By what process does the mind get at all this?" In the same interview, Tesla said that he believed that all fundamental laws could be reduced to one.<ref name="brisbane1">{{cite news |last=Brisbane |first=Arthur |title=OUR FOREMOST ELECTRICIAN. |accessdate=5 September 2012 |newspaper=The World |date=22 July 1894}}</ref>


=== Nobel Prize rumors ===
Near the end of his life, Tesla walked to the park every day to feed the pigeons and even brought injured ones into his hotel room to nurse back to health.<ref>{{cite web |title=About Nikola Tesla |url=http://www.teslasociety.org/about.html |publisher=Tesla Memorial Society of NY |accessdate=5 July 2012}}</ref><ref>{{cite web |title=Tesla Life and Legacy&nbsp;– Poet and Visionary |url=http://www.pbs.org/tesla/ll/ll_poevis.html |publisher=PBS |accessdate=5 July 2012}}</ref> He said that he had been visited by a specific injured white pigeon daily. Tesla spent over $2,000, including building a device that comfortably supported her so her bones could heal, to fix her broken wing and leg.<ref name=autogenerated6 /> Tesla stated, {{quote|I have been feeding pigeons, thousands of them for years. But there was one, a beautiful bird, pure white with light grey tips on its wings; that one was different. It was a female. I had only to wish and call her and she would come flying to me. I loved that pigeon as a man loves a woman, and she loved me. As long as I had her, there was a purpose to my life.<ref>{{cite web |title=Tesla Quotes |url=http://www.teslauniverse.com/nikola-tesla-quote-13 |publisher=Tesla universe |accessdate=5 July 2012}}</ref><ref>{{cite web |title=About Nikola Tesla |url=http://www.teslasociety.org/about.html |publisher=Tesla Society of USA and Canada |accessdate=5 July 2012}}</ref>}}


On 6 November 1915, a ] news agency report from London had the 1915 ] awarded to Thomas Edison and Nikola Tesla; however, on 15 November, a Reuters story from Stockholm stated the prize that year was being awarded to ] and ] "for their services in the analysis of crystal structure by means of X-rays".{{sfn|Cheney|2001|p=245}}<ref>{{cite web |title=The Nobel Prize in Physics 1915 |url=https://www.nobelprize.org/nobel_prizes/physics/laureates/1915/ |publisher=nobelprize.org |access-date=29 July 2012 |archive-date=8 August 2012 |archive-url=https://web.archive.org/web/20120808195305/http://www.nobelprize.org/nobel_prizes/physics/laureates/1915/ |url-status=live }}</ref><ref>{{harvnb|Cheney|Uth|Glenn|1999|p=120}}</ref> There were unsubstantiated rumors at the time that either Tesla or Edison had refused the prize.{{sfn|Cheney|2001|p=245}} The Nobel Foundation said, "Any rumor that a person has not been given a Nobel Prize because he has made known his intention to refuse the reward is ridiculous"; a recipient could decline a Nobel Prize only after he is announced a winner.{{sfn|Cheney|2001|p=245}}
Tesla became a ] in his later years, living on only milk, bread, honey, and vegetable juices.<ref name="seifer1" /><ref>{{cite web |last=GITELMAN |first=LISA |title=Reconciling the Visionary with the Inventor Wizard: The Life and Times of Nikola Tesla |url=http://www.technologyreview.com/business/11619/ |publisher=technology review (MIT) |accessdate=3 June 2012}}</ref>


There have been subsequent claims by Tesla biographers that Edison and Tesla were the original recipients and that neither was given the award because of their animosity toward each other; 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; that both rejected any possibility of sharing it; and even that a wealthy Edison refused it to keep Tesla from getting the $20,000 prize money.{{sfn|Seifer|2001|p=7}}{{sfn|Cheney|2001|p=245}}
=== Appearance ===
].]]
]


In the years after these rumors, neither Tesla nor Edison won a Nobel prize (although Edison received one of 38 possible bids in 1915 and Tesla received one of 38 possible bids in 1937).{{sfn|Seifer|2001|pp=378–380}}
Tesla was {{height|precision=2|ft=6|in=2}} tall and weighed {{convert|142|lb|kg}}, with almost no weight variance from 1888 to about 1926.<ref name=ONeill />{{Rp|292}} He was an elegant, stylish figure in New York City, meticulous in his grooming, clothing, and regimented in his daily activities. {{quote|This was not because of personal vanity. Neatness and fastidiousness in clothes were entirely in harmony with every other phase of his personality. He did not maintain a large wardrobe and he wore no jewelry of any kind&nbsp;... He observed, however, that in the matter of clothes the world takes a man at his own valuation, as expressed in his appearance, and frequently eases his way to his objective through small courtesies not extended to less prepossessing individuals.<ref name=ONeill />{{Rp|289}}}}


=== Other awards, patents and ideas ===
Although many of Tesla's progenitors were dark-eyed, his eyes were gray-blue. He claimed that his eyes were originally darker, but as a result of the exorbitant use of his brain, their hue changed. However, his mother and some of his cousins possessed gray eyes, so it can be inferred that the gray of his eyes was inherited.<ref name=ONeill />{{Rp|327}}
Tesla won numerous medals and awards over this time. They include:


* Grand Officer of the ] (], 1892)
], a newspaper editor for the '']'', described Tesla's appearance: {{quote|Nikola Tesla is almost the tallest, almost the thinnest and certainly the most serious man who goes to Delmonico's regularly&nbsp;... He has eyes set very far back in his head. They are rather light. I asked him how he could have such light eyes and be a Slav. He told me that his eyes were once much darker, but that using his mind a great deal had made them many shades lighter. I have often heard it said that using the brain makes the eyes lighter in color. Tesla's confirmation of the theory through his personal experience is important.
* ] (], US, 1894)<ref name="pg">{{cite book|last1=Goldman|first1=Phyllis|title=Monkeyshines on Great Inventors|date=1997|publisher=EBSCO Publishing, Inc.|location=Greensboro, NC|isbn=978-1-888325-04-1|page=15|url=https://books.google.com/books?id=SKOmiByD_X8C|language=en|access-date=14 May 2020|archive-date=23 March 2024|archive-url=https://web.archive.org/web/20240323123811/https://books.google.com/books?id=SKOmiByD_X8C|url-status=live}}</ref>
* Grand Cross of the ] (], 1895)<ref>{{Cite book|last=Acović|first=Dragomir|title=Slava i čast: Odlikovanja među Srbima, Srbi među odlikovanjima|year=2012|location=Belgrade|publisher=Službeni Glasnik|pages=85}}</ref>
* Member of the ] (US, 1896)<ref>{{Cite web |title=APS Member History |url=https://search.amphilsoc.org/memhist/search?creator=Nikola+Tesla&title=&subject=&subdiv=&mem=&year=&year-max=&dead=&keyword=&smode=advanced |access-date=11 March 2024 |website=American Philosophical Society |archive-date=11 March 2024 |archive-url=https://web.archive.org/web/20240311152707/https://search.amphilsoc.org/memhist/search?creator=Nikola+Tesla&title=&subject=&subdiv=&mem=&year=&year-max=&dead=&keyword=&smode=advanced |url-status=live }}</ref>
* ] (], US, 1916)<ref name="EdisonMedal">{{cite web|title=IEEE Edison Medal Recipient List|url=https://www.ieee.org/content/dam/ieee-org/ieee/web/org/about/awards/recipients/edison_rl.pdf|publisher=Institute of Electrical and Electronics Engineers (IEEE)|access-date=4 June 2022|archive-date=28 January 2021|archive-url=https://web.archive.org/web/20210128155822/https://www.ieee.org/content/dam/ieee-org/ieee/web/org/about/awards/recipients/edison_rl.pdf|url-status=dead}}</ref>
* Grand Cross of the ] (], 1926)<ref name="eserbia">{{cite web|title=Culture|url=http://www.eserbia.org/culture/lectures/288-nikola-tesla-and-the-serbian-orthodox-church-a-st-sava-s-day-reflection|website=www.eserbia.org|access-date=16 January 2017|archive-date=13 February 2017|archive-url=https://web.archive.org/web/20170213134050/http://www.eserbia.org/culture/lectures/288-nikola-tesla-and-the-serbian-orthodox-church-a-st-sava-s-day-reflection|url-status=live}}</ref>
* Cross of the ] (], 1931)
* ] (] & ], US, 1934)<ref name=pg />
* ] (], 1936)
* Grand Cross of the ] (], 1937){{sfn|Cheney|2011|p=312}}
* Medal of the ] (Paris, France, 1937)
* The Medal of the University St. Clement of Ochrida (], 1939)


]
He is very thin, is more than six feet tall and weighs less than a hundred and forty pounds. He has very big hands. Many able men do—Lincoln is one instance. His thumbs are remarkably big, even for such big hands. They are extraordinarily big. This is a good sign. The thumb is the intellectual part of the hand. The apes have very small thumbs. Study them and you will notice this.


Tesla attempted to market several devices based on the production of ]. These included his 1900 Tesla Ozone Company selling an 1896 patented device based on his Tesla coil, used to bubble ozone through different types of oils to make a therapeutic gel.<ref>Anand Kumar Sethi (2016). ''The European Edisons: Volta, Tesla, and Tigerstedt'', Springer. pp. 53–54</ref> He also tried to develop a variation of this a few years later as a room sanitizer for hospitals.{{sfn|Carlson|2013|p=353}}
Nikola Tesla has a head that spreads out at the top like a fan. His head is shaped like a wedge. His chin is as pointed as an ice-pick. His mouth is too small. His chin, though not weak, is not strong enough. His face cannot be studied and judged like the faces of other men, for he is not a worker in practical fields. He lives his life up in the top of his head, where ideas are born, and up there he has plenty of room. His hair is jet black and curly. He stoops—most men do when they have no peacock blood in them. He lives inside of himself. He takes a profound interest in his own work. He has that supply of self-love and self-confidence which usually goes with success. And he differs from most of the men who are written and talked about in the fact that he has something to tell.<ref name="brisbane1" />}}


Tesla theorized that the application of electricity to the brain enhanced intelligence. In 1912, he crafted "a plan to make dull students bright by saturating them unconsciously with electricity," wiring the walls of a schoolroom and, "saturating with infinitesimal electric waves vibrating at high frequency. The whole room will thus, Mr. Tesla claims, be converted into a health-giving and stimulating electromagnetic field or 'bath.'"<ref name="Gilliams">{{cite web |last1=Gilliams |first1=E. Leslie |title=Tesla's Plan of Electrically Treating Schoolchildren |url=http://www.teslacollection.com/tesla_articles/1912/popular_electricity_magazine/e_leslie_gilliams/tesla_s_plan_of_electrically_treating_school_children |via=teslacollection.com |work=Popular Electricity Magazine |date=1912 |access-date=19 August 2014 |archive-date=9 January 2015 |archive-url=https://web.archive.org/web/20150109004431/http://www.teslacollection.com/tesla_articles/1912/popular_electricity_magazine/e_leslie_gilliams/tesla_s_plan_of_electrically_treating_school_children |url-status=live }}</ref> The plan was, at least provisionally, approved by then superintendent of New York City schools, William H. Maxwell.<ref name="Gilliams" />
=== Eidetic memory ===
<!-- "Early years (1856–1885)" section of THIS article links here. Please fix link if changing section title -->
Tesla read many works, memorizing complete books, and supposedly possessed a ].<ref name=Cheney />{{Rp|33}} He was a ], speaking eight languages: Serbo-Croatian, Czech, English, French, German, Hungarian, Italian, and Latin.<ref name=ONeill />{{Rp|282}} 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. Often, 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 encountered. Just by hearing the name of an item, he would be able to envision it in realistic detail. 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 ]. He typically did not make drawings by hand but worked from memory. Beginning in his childhood, Tesla had frequent flashbacks to events that had happened previously in his life.<ref name=Cheney />{{Rp|33}}


Before ], Tesla sought overseas investors. After the war started, Tesla lost the funding he was receiving from his patents in European countries.
=== Sleep habits ===
Tesla claimed to never sleep more than two hours.<ref name=ONeill />{{Rp|46}} However, Tesla did admit to "dozing" from time to time "to recharge his batteries."<ref name=autogenerated11 />


In the August 1917 edition of the magazine '']'', Tesla postulated that electricity could be used to locate submarines via using the reflection of an "electric ray" of "tremendous frequency," with the signal being viewed on a fluorescent screen (a system that has been noted to have a superficial resemblance to modern ]).<ref>Margaret Cheney, Robert Uth, Jim Glenn, ''Tesla, Master of Lightning,'' pp. 128–129</ref> Tesla was incorrect in his assumption that high-frequency radio waves would penetrate water.<ref>{{cite book|url=https://books.google.com/books?id=W1JAeg1PiWIC&pg=PA154|title=Lewis Coe (2006). ''Wireless Radio: A History''. McFarland. p. 154|isbn=978-0-7864-2662-1|last1=Coe|first1=Lewis|date=8 February 2006|publisher=McFarland }}</ref> ], who helped develop France's first radar system in the 1930s, noted in 1953 that Tesla's general speculation that a very strong high-frequency signal would be needed was correct. Girardeau said, "(Tesla) was prophesying or dreaming, since he had at his disposal no means of carrying them out, but one must add that if he was dreaming, at least he was dreaming correctly".{{sfn|Cheney|2001|p=266}}
During his second year of study at Graz, 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.<ref name=ONeill />{{Rp|43, 301}} On one occasion at his laboratory, Tesla worked for a period of 84 hours without sleep or rest.<ref name=ONeill />{{Rp|208}}


In 1928, Tesla received patent, {{US patent|1,655,114}}, for a ] design capable of ] (VTOL), which "gradually tilted through manipulation of the elevator devices" in flight until it was flying like a conventional plane.<ref>{{cite web |last=Tesla |first=Nikola |title=TESLA PATENT 1,655,114 APPARATUS FOR AERIAL TRANSPORTATION. |url=https://teslauniverse.com/nikola-tesla-patents-1,655,114-aerial-transportation |publisher=U.S. Patent Office |access-date=20 July 2012 |archive-date=20 July 2012 |archive-url=https://web.archive.org/web/20120720092018/http://www.teslauniverse.com/nikola-tesla-patents-1,655,114-aerial-transportation |url-status=live }}</ref> This impractical design was something Tesla thought would sell for less than $1,000.{{sfn|Cheney|2001|p=251}}<ref name="airspacemag">{{cite web |url=https://www.smithsonianmag.com/air-space-magazine/nikola-teslas-curious-contrivance-10187565/ |title="Nikola Tesla's Curious Contrivance" by A.J.S. RAYL Air & Space magazine, September 2006, reprint at History of Flight |publisher=airspacemag.com |access-date=10 September 2012 |archive-date=27 January 2022 |archive-url=https://web.archive.org/web/20220127184244/https://www.smithsonianmag.com/air-space-magazine/nikola-teslas-curious-contrivance-10187565/ |url-status=live }}</ref>
Kenneth Swezey, a journalist whom Tesla had befriended, confirmed that Tesla rarely slept. Swezey recalled one morning when Tesla called him at 3 a.m.: "I was sleeping in my room like one dead&nbsp;... Suddenly, the telephone ring awakened me&nbsp;... spoke animatedly, with pauses, &nbsp;... work out a problem, comparing one theory to another, commenting; and when he felt he had arrived at the solution, he suddenly closed the telephone."<ref name=autogenerated11 />


Tesla had a further office at 350 Madison Ave<ref>Valentine Korah, An Introductory Guide to EC Competition Law and Practice, Sweet & Maxwell – 1928, page 235</ref> but by 1928 he no longer had a laboratory or funding.<ref name="airspacemag" />
=== Relationships ===
]
Tesla never married, saying that his chastity was very helpful to his scientific abilities.<ref name=Cheney />{{Rp|33}} However, toward the end of his life, he told a reporter, "Sometimes I feel that by not marrying, I made too great a sacrifice to my work&nbsp;..."<ref name="autogenerated6" /> There have been numerous accounts of women vying for Tesla's affection, even some madly in love with him.{{Citation needed|date=September 2012}} Tesla, though polite and soft-spoken, did not have any known relationships.


=== Living circumstances ===
Tesla was asocial, and prone to seclude himself with his work.<ref>{{cite book |title=The Race for Wireless: How Radio was Invented (or Discovered?) |year=2011 |publisher=AuthorHouse |isbn=978-1-4634-3750-3 |page=36 |first=Gregory |last=Malanowski |accessdate=12 May 2013 |quote=Tesla was definitely asocial, a loner. Although in his younger years he was immensely popular and admired by many rich, socialite women, there were no women in his life.}}</ref>{{Sfn |Cheney|Uth|Glenn|1999| loc =Preface}}<ref name=Jonnes /><ref>{{cite book |title=AC/DC: The Savage Tale of the First Standards War |year=2011 |publisher=John Wiley & Sons |isbn=978-1-118-04702-6 |pages=163–64 |first=Tom |last=McNichol |accessdate=12 May 2013 |quote=Tesla's peculiar nature made him a solitary man, a loner in a field that was becoming so complex that it demanded collaboration.}}</ref> However, when he did engage in a social life, many people spoke very positively and admiringly of Tesla. Robert Underwood Johnson described him as attaining a "distinguished sweetness, sincerity, modesty, refinement, generosity, and force."<ref name="autogenerated6" /> 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."<ref name= ONeill /> Tesla's friend, ], wrote, "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."{{Citation needed | date =August 2012}}
Tesla lived at the ] in New York City from 1900 and ran up a large bill.{{sfn|Cheney|Uth|Glenn|1999|p=125}} He moved to the ] in 1922 and followed a pattern from then on of moving to a different hotel every few years and leaving unpaid bills behind.{{sfn|Carlson|2013|p=467-468}}{{sfn|O'Neill|1944|p=359}}


Tesla walked to the park every day to feed the pigeons. He began feeding them at the window of his hotel room and nursed injured birds back to health.{{sfn|O'Neill|1944|p=359}}<ref>{{cite web|title=About Nikola Tesla |url=http://www.teslasociety.org/about.html |publisher=Tesla Memorial Society of NY |access-date=5 July 2012 |url-status=dead |archive-url=https://web.archive.org/web/20120525133151/http://www.teslasociety.org/about.html |archive-date=25 May 2012 }}</ref><ref>{{cite web |title=Tesla Life and Legacy&nbsp;– Poet and Visionary |url=https://www.pbs.org/tesla/ll/ll_poevis.html |publisher=PBS |access-date=5 July 2012 |archive-date=8 July 2012 |archive-url=https://web.archive.org/web/20120708101441/http://www.pbs.org/tesla/ll/ll_poevis.html |url-status=live }}</ref> He said that he had been visited by a certain injured white pigeon daily. He spent over $2,000 ({{Inflation|US|2000|1922|r=-1|fmt=eq}}) to care for the bird, including a device he built to support her comfortably while her broken wing and leg healed.{{sfn|Seifer|2001|p=414}} Tesla stated:
] in Tesla's lab, early 1894]]
Tesla was a good friend of ],<ref name="teslasociety1" /> ], ],<ref>{{cite web |title=Stanford White |url=http://www.teslasociety.com/stanford.htm |publisher=Tesla Memorial Society of NY |accessdate=4 July 2012}}</ref> Fritz Lowenstein, George Scherff, and Kenneth Swezey.<ref>{{citation |first=Kenneth M |last=Swezey |title=Papers 1891–1982 |volume=47 |url=http://americanhistory.si.edu/archives/d8047.htm |publisher=National Museum of American History |accessdate=4 July 2012}}</ref><ref>{{cite web |title=Tribute to Nikola Tesla |url=http://www.teslasociety.com/posterbook.htm |publisher=Tesla Memorial Society of NY |accessdate=4 July 2012}}</ref><ref>{{cite web |title=Nikola Tesla at Wardenclyffe |url=http://www.teslasociety.com/warden.htm |publisher=Tesla Memorial Society of NY |accessdate=4 July 2012}}</ref> In middle age, Tesla became a close friend of ]. They spent a lot of time together in his lab and elsewhere.<ref name="teslasociety1">{{cite web |title=Famous Friends |url=http://www.teslasociety.com/famousfriends.htm |publisher=Tesla Memorial Society of NY |accessdate=4 July 2012}}</ref> Twain notably described Tesla's induction motor invention as "the most valuable patent since the telephone."<ref>{{cite news |title=Nikola Tesla: The patron saint of geeks? |url=http://www.bbc.co.uk/news/magazine-19503846 |work=News Magazine |publisher=BBC |accessdate=10 September 2012 |date=10 September 2012}}</ref> In the late 1920s, Tesla befriended ], a poet, writer, mystic, and later, a ] propagandist. Tesla occasionally attended dinner parties held by Viereck and his wife.<ref>Cheney, Margaret & Robert Uth (2001). ''Tesla: Master of Lightning''. Barnes & Noble Books, p. 137.</ref><ref>{{cite book |last=Johnson |first=Neil M |title=George Sylvester Viereck: Poet and Propagandist |publisher=Neil M Johnson}}</ref>


{{blockquote|I have been feeding pigeons, thousands of them for years. But there was one, a beautiful bird, pure white with light grey tips on its wings; that one was different. It was a female. I had only to wish and call her and she would come flying to me. I loved that pigeon as a man loves a woman, and she loved me. As long as I had her, there was a purpose to my life.<ref>{{cite web|title=About Nikola Tesla |url=http://www.teslasociety.org/about.html |publisher=Tesla Society of USA and Canada |access-date=5 July 2012 |url-status=dead |archive-url=https://web.archive.org/web/20120525133151/http://www.teslasociety.org/about.html |archive-date=25 May 2012 }}</ref>}}
Tesla could be harsh at times, openly expressing disgust for overweight people, such as when he fired a secretary because of her weight.<ref name=Cheney />{{Rp|110}} He was quick to criticize clothing. On several occasions, Tesla directed a subordinate to go home and change her dress.<ref name=Cheney />{{Rp|33}}


Tesla's unpaid bills, as well as complaints about the mess made by pigeons, led to his eviction from St. Regis in 1923. He was also forced to leave the ] in 1930 and the Hotel Governor Clinton in 1934.{{sfn|O'Neill|1944|p=359}} At one point he also took rooms at the ].{{sfn|Cheney|Uth|Glenn|1999|p=135}}
When Thomas Edison died in 1931, Tesla contributed the only negative opinion to the '']'', buried in an extensive coverage of Edison's life:
{{quote |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&nbsp;... 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.<ref name="lifeEdison">{{cite book |title=Thomas Edison: Life of an Electrifying Man |last=Biographiq |year=2008 |isbn=9781599862163 |page=23 |publisher=Filiquarian Publishing, LLC. |accessdate=23 September 2014}}</ref>}}


Tesla moved to the ] in 1934. At this time Westinghouse Electric & Manufacturing Company began paying him $125 ({{Inflation|US|125|1934|r=-1|fmt=eq}}) per month in addition to paying his rent. Accounts of how this came about vary. Several sources claim that Westinghouse was concerned, or possibly warned, about potential bad publicity arising from the impoverished conditions in which their former star inventor was living.{{sfn|Jonnes|2004|p=365}}<ref>{{harvnb|Cheney|Uth|Glenn|1999|p=149}}</ref><ref name="Seifer435">{{harvnb|Seifer|2001|p=435}}</ref>{{sfn|Carlson|2013|p=379}} The payment has been described as being couched as a "consulting fee" to get around Tesla's aversion to accepting charity. Tesla biographer Marc Seifer described the Westinghouse payments as a type of "unspecified settlement".<ref name="Seifer435" />
=== Views on experimental and theoretical physics ===
<!-- Deleted image removed: ] -->


=== Birthday press conferences ===
Tesla exhibited a pre-atomic understanding of physics in his writings;<ref>{{cite book |url=http://books.google.com/books?id=ZNqo1zaZRTYC&pg=PA181&lpg=PA181&dq=tesla+education+atomic+physics&source=bl&ots=ZJ_NJfpmSP&sig=pyuGct0TP-UXLdtmLPSrGqAnMt0&hl=en#v=onepage&q=tesla%20education%20atomic%20physics&f=false |title=Thomas Valone, Harnessing the Wheelwork of Nature: Tesla's Science of Energy, Adventures Unlimited Press, 2002, p. 181 |publisher=Books.google.com |accessdate=18 March 2013}}</ref> he disagreed with the theory of atoms being composed of smaller ]s, stating there was no such thing as an ] creating an electric charge (he believed that if electrons existed at all, they were some fourth state of matter or "sub-atom" that could only exist in an experimental vacuum and that they had nothing to do with electricity).<ref name=ONeill />{{Rp|249}}<ref>{{cite book |url=http://books.google.com/books?id=tCcDAAAAMBAJ&pg=PA171&lpg=PA171&dq=tesla+believe+electron&source=bl&ots=XwEJcSlWTw&sig=jjOQ3wg9FqkIow7TA4fR4HDaVIg&hl=en&sa=X&ei=5J9TUJPNJYP20gHSyoCoBA&ved=0CEAQ6AEwAw#v=onepage&q=tesla%20believe%20electron&f=false |title="The Profit of Science Looks Into The Future," Popular Science November 1928, p. 171 |publisher=Books.google.com |accessdate=18 March 2013}}</ref> Tesla believed that atoms are immutable—they could not change state or be split in any way. He was a believer in the 19th century concept of an all pervasive "]" that transmitted electrical energy.<ref>{{harvnb|Seifer|2001|p=1745}}</ref>
] commemorating his 75th birthday]]
In 1931, a young journalist whom Tesla befriended, ], organized a celebration for the inventor's 75th birthday.<ref>{{Cite web|url=http://www.davidjkent-writer.com/2012/07/10/happy-birthday-nikola-tesla-a-scientific-rock-star-is-born/|title=Happy Birthday, Nikola Tesla – A Scientific Rock Star is Born|last=Kent|first=David J.|date=10 July 2012|website=Science Traveler|language=en-US|access-date=26 January 2019|archive-date=26 January 2019|archive-url=https://web.archive.org/web/20190126221049/http://www.davidjkent-writer.com/2012/07/10/happy-birthday-nikola-tesla-a-scientific-rock-star-is-born/|url-status=live}}</ref> Tesla received congratulations from figures in science and engineering such as ],<ref>{{cite web|url=http://www.teslasociety.com/time.jpg|title=Time front cover, Vol XVIII, No. 3|date=20 July 1931|access-date=10 September 2012|archive-date=7 July 2018|archive-url=https://web.archive.org/web/20180707163714/http://www.teslasociety.com/time.jpg|url-status=live}}</ref> and he was also featured on the cover of ].<ref>{{cite magazine |title=Nikola Tesla|url=http://www.time.com/time/covers/0,16641,19310720,00.html|archive-url=https://web.archive.org/web/20070708020011/http://www.time.com/time/covers/0,16641,19310720,00.html|url-status=dead|archive-date=8 July 2007|magazine=Time|access-date=2 July 2012}}</ref> The cover caption "All the world's his power house" noted his contribution to ]. The party went so well that Tesla made it an annual event, an occasion where he would put out a large spread of food and drink—featuring dishes of his own creation. He invited the press in order to see his inventions and hear stories about his past exploits, views on current events, and sometimes baffling claims.{{sfn|Cheney|2001|p=151}}{{sfn|Carlson|2013|pp=380–382}}


]
Tesla was generally antagonistic towards theories about the conversion of matter into energy.<ref name=ONeill />{{Rp|247}} He was also critical of Einstein's ], saying:
At the 1932 party, Tesla claimed he had invented a motor that would run on ]s.{{sfn|Carlson|2013|pp=380–382}}
In 1933, at age 77, Tesla told reporters at the event that, after 35 years of work, he was on the verge of producing proof of a new form of energy. He claimed it was a theory of energy that was "violently opposed" to Einsteinian physics and could be tapped with an apparatus that would be cheap to run and last 500 years. He also told reporters he was working on a way to transmit individualized private radio wavelengths, working on breakthroughs in ], and developing a way to photograph the ] to record thought.<ref>Tesla Predicts New Source of Power in Year, New York Herald Tribune, 9 July 1933</ref>


At the 1934 occasion, Tesla told reporters he had designed a ] he claimed would end all war.<ref>{{cite magazine |title=Tesla's Ray |magazine=Time |date=23 July 1934}}</ref><ref name="seifer1">{{cite web |last=Seifer |first=Marc |title=Tesla's "Death Ray" Machine |url=http://www.bibliotecapleyades.net/tesla/esp_tesla_2.htm |publisher=bibliotecapleyades.net |access-date=4 July 2012 |archive-date=24 June 2006 |archive-url=https://web.archive.org/web/20060624171605/http://www.bibliotecapleyades.net/tesla/esp_tesla_2.htm |url-status=live }}</ref> He called it "]", but was usually referred to as his ].<ref>Cheney, Margaret & Uth, Robert (2001). Tesla: Master of Lightning. Barnes & Noble Books. p. 158</ref> In 1940, the '']'' gave a range for the ray of {{convert|250|mi}}, with an expected development cost of US$2&nbsp;million (equivalent to ${{Inflation|US|2|1940|r=2}}&nbsp;million in {{Inflation/year|US}}).<ref name="pmnyt1940">{{cite web |url=https://www.popularmechanics.com/science/energy/a44197280/did-the-us-government-steal-nikola-teslas-research/ |title=Did the U.S. Government Really Steal Nikola Tesla's Research Papers? |first=Jessica |last=Coulon |date=14 June 2023 |accessdate=26 June 2023 |work=] |archive-date=26 June 2023 |archive-url=https://web.archive.org/web/20230626231358/https://www.popularmechanics.com/science/energy/a44197280/did-the-us-government-steal-nikola-teslas-research/ |url-status=live }}</ref> Tesla described it as a defensive weapon that would be put up along the border of a country and be used against attacking ground-based infantry or aircraft. Tesla never revealed detailed plans of how the weapon worked during his lifetime but, in 1984, they surfaced at the ] archive in ].{{sfn|Carlson|2013|p=382}} The treatise, ''The New Art of Projecting Concentrated Non-dispersive Energy through the Natural Media'', described an open-ended vacuum tube with a gas jet seal that allows particles to exit, a method of charging slugs of tungsten or mercury to millions of volts, and directing them in streams (through ] repulsion).{{sfn|Carlson|2013|pp=380–382}}{{sfn|Seifer|1998|p=454}} Tesla tried to attract interest of the ],<ref>"Aerial Defense 'Death-Beam' Offered to U.S. By Tesla" 12 July 1940</ref> United Kingdom, Soviet Union, and Yugoslavia in the device.<ref>{{cite web |last=Seifer |first=Marc J. |title=Tesla's "death ray" machine |url=http://www.bibliotecapleyades.net/tesla/esp_tesla_2.htm |access-date=5 September 2012 |archive-date=24 June 2006 |archive-url=https://web.archive.org/web/20060624171605/http://www.bibliotecapleyades.net/tesla/esp_tesla_2.htm |url-status=live }}</ref>
{{quote|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.<ref>'']'', 11 September 1932</ref>}}


In 1935, at his 79th birthday party, Tesla covered many topics. He claimed to have discovered the cosmic ray in 1896 and invented a way to produce direct current by ], and made many claims about his ].<ref name="ReferenceA">Earl Sparling, NIKOLA TESLA, AT 79, USES EARTH TO TRANSMIT SIGNALS: EXPECTS TO HAVE $100,000,000 WITHIN TWO YEARS, New York World-Telegram, 11 July 1935</ref> Describing the device (which he expected would earn him $100 million within two years) he told reporters that a version of his oscillator had caused an earthquake in his 46 East Houston Street lab and neighboring streets in ] in 1898.<ref name="ReferenceA" /> He went on to tell reporters his oscillator could destroy the ] with {{convert|5|lb}} of air pressure.{{sfn|Carlson|2013|p=380}} He also proposed using his oscillators to transmit vibrations into the ground. He claimed it would work over any distance and could be used for communication or locating underground mineral deposits, a technique he called "]".<ref name="Anderson" />
Tesla claimed to have developed his own physical principle regarding matter and energy that he started working on in 1892,<ref name=ONeill /> and in 1937, at age 81, claimed in a letter to have completed a "dynamic theory of gravity" that ''" put an end to idle speculations and false conceptions, as that of curved space."''<ref>{{cite web |title=Nikola Tesla |url=http://www.famousscientists.org/nikola-tesla |publisher=FamousScientists.org |accessdate=15 December 2011}}</ref> He stated that the theory was "worked out in all details" and that he hoped to soon give it to the world.<ref> downloadable from www.tesla.hu</ref> Further elucidation of his theory was never found in his writings.<ref name=Cheney />{{Rp|309}}


In 1937, at his Grand Ballroom of Hotel New Yorker event, Tesla received the ] from the Czechoslovak ambassador and a medal from the Yugoslav ambassador. On questions concerning the death ray, Tesla stated: "But it is not an experiment&nbsp;... I have built, demonstrated and used it. Only a little time will pass before I can give it to the world."{{sfn|Carlson|2013|pp=380–382}}
=== Views on society ===
Tesla, like many of his era, became a proponent of an imposed ] version of ]. His opinion stemmed from the belief that humans' "pity" had interfered with the natural "ruthless workings of nature," rather than from 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:
{{quote |...&nbsp;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&nbsp;... 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.<ref>{{cite web |url=http://www.pbs.org/tesla/res/res_art11.html |title=A Machine to End War |date=February 1937 |publisher=Public Broadcasting Service |accessdate=23 November 2010}}</ref>}}


== Death ==
In 1926, Tesla commented on the ills of the social subservience of women and the struggle of women toward ], indicated that humanity's future would be run by "]s." He believed that women would become the dominant sex in the future.<ref>Kennedy, John B., "'', An interview with Nikola Tesla''." ], 30 January 1926.</ref>
], where Tesla died]]
]

In the fall of 1937 at the age of 81, after midnight one night, Tesla left the Hotel New Yorker to make his regular commute to the cathedral and library to feed the pigeons. While crossing a street a couple of blocks from the hotel, Tesla was struck by a moving taxicab and was thrown to the ground. His back was severely wrenched and three of his ribs were broken in the accident. The full extent of his injuries was never known; Tesla refused to consult a doctor, an almost lifelong custom, and never fully recovered.{{sfn|O'Neill|1944|p=313}}{{sfn|Carlson|2013|p=389}}

On 7 January 1943, at the age of 86, Tesla died alone in Room 3327 of the ]. His body was found by maid Alice Monaghan when she entered Tesla's room, ignoring the "do not disturb" sign that Tesla had placed on his door two days earlier. Assistant medical examiner H.W. Wembley examined the body and ruled that the cause of death had been ] (a type of heart attack).

Two days later the ] ordered the ] to seize Tesla's belongings. ], a professor at ] and a well-known electrical engineer serving as a technical aide to the ], was called in to analyze the Tesla items. After a three-day investigation, Trump's report concluded that there was nothing which would constitute a hazard in unfriendly hands, stating:

{{blockquote|His thoughts and efforts during at least the past 15 years were primarily of a speculative, philosophical, and somewhat promotional character often concerned with the production and wireless transmission of power; but did not include new, sound, workable principles or methods for realizing such results.<ref name="autogeneratedll">{{cite web |title=The Missing Papers |url=https://www.pbs.org/tesla/ll/ll_mispapers.html |publisher=PBS |access-date=5 July 2012 |archive-date=24 January 2001 |archive-url=https://web.archive.org/web/20010124064300/https://www.pbs.org/tesla/ll/ll_mispapers.html |url-status=live }}</ref>}}

In a box purported to contain a part of Tesla's "death ray", Trump found a 45-year-old ].<ref>{{harvnb|Childress|1993|p=249}}</ref>

On 10 January 1943, New York City mayor ] read a eulogy written by Slovene-American author ] live over ] radio while violin pieces "]" and "]" were played in the background. On 12 January, two thousand people attended a state funeral for Tesla at the ] in Manhattan. After the funeral, Tesla's body was taken to the ] in Ardsley, New York, where it was later cremated. The following day, a second service was conducted by prominent priests in the Trinity Chapel (today's ]) in New York City.

== Personal life and character ==

]

Tesla was a lifelong bachelor, who had once explained that his chastity was very helpful to his scientific abilities.{{sfn|Cheney|2001|p=33}} In an interview with the ''Galveston Daily News'' on 10 August 1924 he stated, "Now the soft-voiced gentlewoman of my reverent worship has all but vanished. In her place has come the woman who thinks that her chief success in life lies in making herself as much as possible like man—in dress, voice and actions..."{{sfn|Cheney|Uth|Glenn|1999|p=135}} Although he told a reporter in later years that he sometimes felt that by not marrying, he had made too great a sacrifice to his work,{{sfn|Seifer|2001|p=414}} Tesla chose to never pursue or engage in any known relationships, instead finding all the stimulation he needed in his work.

Tesla was asocial and prone to seclude himself with his work.{{sfn|Jonnes|2004}}{{Sfn|Cheney|Uth|Glenn|1999|loc=Preface}}<ref>{{cite book|title=AC/DC: The Savage Tale of the First Standards War|year=2011|publisher=John Wiley & Sons|isbn=978-1-118-04702-6|pages=163–64|first=Tom|last=McNichol|quote=Tesla's peculiar nature made him a solitary man, a loner in a field that was becoming so complex that it demanded collaboration.}}</ref> However, when he did engage in social life, many people spoke very positively and admiringly of Tesla. ] described him as attaining a "distinguished sweetness, sincerity, modesty, refinement, generosity, and force".{{sfn|Seifer|2001|p=130}} His secretary, Dorothy Skerrit, wrote: "his genial smile and nobility of bearing always denoted the gentlemanly characteristics that were so ingrained in his soul".{{sfn|O'Neill|1944|p=289}} Tesla's friend, ], wrote, "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".{{sfn|Cheney|2001|p=80}}

Tesla was a good friend of ], Robert Underwood Johnson,<ref name="teslasociety1" /> ],<ref>{{cite web|title=Stanford White|url=http://www.teslasociety.com/stanford.htm|publisher=Tesla Memorial Society of NY|access-date=4 July 2012|archive-date=28 November 2010|archive-url=https://web.archive.org/web/20101128204919/http://teslasociety.com/stanford.htm|url-status=live}}</ref> Fritz Lowenstein, George Scherff, and Kenneth Swezey.<ref>{{citation|first=Kenneth M.|last=Swezey|title=Papers 1891–1982|volume=47|url=http://americanhistory.si.edu/archives/d8047.htm|publisher=National Museum of American History|access-date=4 July 2012|url-status=dead|archive-url=https://web.archive.org/web/20120505004025/http://americanhistory.si.edu/archives/d8047.htm|archive-date=5 May 2012}}</ref><ref>{{cite web|title=Tribute to Nikola Tesla|url=http://www.teslasociety.com/posterbook.htm|publisher=Tesla Memorial Society of NY|access-date=4 July 2012|archive-date=13 June 2011|archive-url=https://web.archive.org/web/20110613113120/http://teslasociety.com/posterbook.htm|url-status=live}}</ref><ref>{{cite web|title=Nikola Tesla at Wardenclyffe|url=http://www.teslasociety.com/warden.htm|publisher=Tesla Memorial Society of NY|access-date=4 July 2012|archive-date=29 November 2010|archive-url=https://web.archive.org/web/20101129042338/http://teslasociety.com/warden.htm|url-status=live}}</ref> In middle age, Tesla became a close friend of ]; they spent a lot of time together in his lab and elsewhere.<ref name="teslasociety1">{{cite web|title=Famous Friends|url=http://www.teslasociety.com/famousfriends.htm|publisher=Tesla Memorial Society of NY|access-date=4 July 2012|archive-date=28 November 2010|archive-url=https://web.archive.org/web/20101128190309/http://teslasociety.com/famousfriends.htm|url-status=live}}</ref> Twain notably described Tesla's ] invention as "the most valuable patent since the telephone".<ref>{{cite news|title=Nikola Tesla: The patron saint of geeks?|url=https://www.bbc.co.uk/news/magazine-19503846|work=News Magazine|publisher=BBC|access-date=10 September 2012|date=10 September 2012|archive-date=10 September 2012|archive-url=https://web.archive.org/web/20120910191948/http://www.bbc.co.uk/news/magazine-19503846|url-status=live}}</ref> At a party thrown by actress ] in 1896, Tesla met Indian Hindu monk ]. Vivekananda later wrote that Tesla said he could demonstrate mathematically the relationship between matter and energy, something Vivekananda hoped would give a scientific foundation to ] cosmology.<ref>Kak, S. (2017) Tesla, wireless energy transmission and Vivekananda. Current Science, vol. 113, 2207–2210.</ref><ref>{{cite book|url=https://books.google.com/books?id=30PeCQAAQBAJ&q=tesla+Vivekananda&pg=PT24|title=Swami Vivekananda: A Contemporary Reader edited by Makarand R. Paranjape|isbn=978-1-317-44636-1|last1=Paranjape|first1=Makarand R.|date=12 June 2015|publisher=Routledge|access-date=4 May 2021|archive-date=23 March 2024|archive-url=https://web.archive.org/web/20240323124315/https://books.google.com/books?id=30PeCQAAQBAJ&q=tesla+Vivekananda&pg=PT24#v=snippet&q=tesla%20Vivekananda&f=false|url-status=live}}</ref> The meeting with Swami Vivekananda stimulated Tesla's interest in Eastern Science, which led to Tesla studying Hindu and ] for a number of years.<ref>{{Cite web |title=Nikola Tesla and Swami Vivekananda |url=https://www.teslasociety.com/tesla_and_swami.htm |access-date=20 December 2022 |website=www.teslasociety.com |archive-date=20 December 2022 |archive-url=https://web.archive.org/web/20221220143353/https://www.teslasociety.com/tesla_and_swami.htm |url-status=live }}</ref> Tesla later wrote an article titled "Man's Greatest Achievement" using Sanskrit terms ] and ] to describe the relationship between matter and energy.<ref>{{Cite web |title=The Influence Vedic Philosophy Had on Nikola Tesla's Idea of Free Energy – SAND |url=https://www.scienceandnonduality.com/article/the-influence-vedic-philosophy-had-on-nikola-teslas-idea-of-free-energy |access-date=20 December 2022 |website=The Influence Vedic Philosophy Had on Nikola Tesla’s Idea of Free Energy – SAND |language=en |archive-date=20 December 2022 |archive-url=https://web.archive.org/web/20221220143355/https://www.scienceandnonduality.com/article/the-influence-vedic-philosophy-had-on-nikola-teslas-idea-of-free-energy |url-status=live }}</ref><ref>{{Cite web |title=(PDF) Tesla (1930)-Man's Greatest Achievement.pdf |url=https://dokumen.tips/documents/tesla-1930-mans-greatest-achievementpdf.html |access-date=20 December 2022 |website=dokumen.tips |language=en |archive-date=20 December 2022 |archive-url=https://web.archive.org/web/20221220143359/https://dokumen.tips/documents/tesla-1930-mans-greatest-achievementpdf.html |url-status=live }}</ref> In the late 1920s, Tesla befriended ], a poet, writer, mystic, and later, a ] propagandist. Tesla occasionally attended dinner parties held by Viereck and his wife.<ref>{{cite book|last1=Cheney |first1=Margaret|last2=Uth |first2=Robert|name-list-style=amp|date=2001|title=Tesla: Master of Lightning|publisher=Barnes & Noble Books|page=137}}</ref><ref>{{cite book|last=Johnson|first=Neil M.|title=George Sylvester Viereck: Poet and Propagandist|publisher=Neil M. Johnson}}</ref>

Tesla could be harsh at times and openly expressed disgust for overweight people, such as when he fired a secretary because of her weight.{{sfn|Cheney|2001|p=110}} He was quick to criticize clothing; on several occasions, Tesla directed a subordinate to go home and change her dress.{{sfn|Cheney|2001|p=33}} When ] died in 1931, Tesla contributed the only negative opinion to '']'', buried in an extensive coverage of Edison's life:

{{blockquote|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&nbsp;... 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.<ref name="lifeEdison">{{cite book |title=Thomas Edison: Life of an Electrifying Man |last=Biographiq |year=2008 |isbn=978-1-59986-216-3 |page=23 |publisher=Filiquarian Publishing, LLC.}}</ref><ref name="Edisonobit">{{cite news |author=<!--not stated--> |title=Tesla says Edison was an empiricist |date=19 October 1931 |work=New York Times |page=27 |url=https://timesmachine.nytimes.com/timesmachine/1931/10/19/issue.html |access-date=15 January 2024 |ref=none |archive-date=23 March 2024 |archive-url=https://web.archive.org/web/20240323124240/https://timesmachine.nytimes.com/timesmachine/1931/10/19/issue.html |url-status=live }}</ref>}}

Tesla became a vegetarian in his later years, living on only milk, bread, honey, and vegetable juices.<ref name="seifer1" /><ref>{{cite web |last=Gitelman |first=Lisa |title=Reconciling the Visionary with the Inventor Wizard: The Life and Times of Nikola Tesla |url=https://www.technologyreview.com/1997/11/01/237150/reconciling-the-visionary-with-the-inventor/ |publisher=technology review (MIT) |access-date=3 June 2012 |date=1 November 1997 |archive-date=22 September 2020 |archive-url=https://web.archive.org/web/20200922054715/https://www.technologyreview.com/1997/11/01/237150/reconciling-the-visionary-with-the-inventor/ |url-status=live }}</ref>

== Views and beliefs ==
]
=== On experimental and theoretical physics ===
Tesla disagreed with the theory of atoms being composed of smaller ]s, stating there was no such thing as an ] creating an electric charge. He believed that if electrons existed at all, they were some fourth state of matter or "sub-atom" that could exist only in an experimental vacuum and that they had nothing to do with electricity.{{sfn|O'Neill|1944|p=249}}<ref>{{cite book |url=https://books.google.com/books?id=tCcDAAAAMBAJ&pg=PA171 |title="The Prophet of Science Looks Into The Future," Popular Science November 1928, p. 171 |access-date=18 March 2013 |date=November 1928 |archive-date=23 March 2024 |archive-url=https://web.archive.org/web/20240323124316/https://books.google.com/books?id=tCcDAAAAMBAJ&pg=PA171#v=onepage&q&f=false |url-status=live }}</ref> Tesla believed that atoms are immutable—they could not change state or be split in any way. He was a believer in the 19th-century concept of an all-pervasive ] that transmitted electrical energy.<ref>{{harvnb|Seifer|2001|p=1745}}</ref>

Tesla was generally antagonistic towards theories about the conversion of matter into energy.{{sfn|O'Neill|1944|p=247}} He was also critical of Einstein's ], saying:

{{blockquote|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.<ref>'']'', 11 September 1932</ref>}}

In 1935 he described relativity as "a beggar wrapped in purple whom ignorant people take for a king" and said his own experiments had measured the speed of cosmic rays from Arcturus as fifty times the speed of light.<ref>{{Cite web |title=Tesla, 79, Promises to Transmit Force |url=http://teslaresearch.jimdofree.com/articles-interviews/tesla-79-promises-to-transmit-force-new-york-times-july-11-1935/ |access-date=6 July 2022 |website=Open Tesla Research |language=en-US |archive-date=1 July 2022 |archive-url=https://web.archive.org/web/20220701054231/https://teslaresearch.jimdofree.com/articles-interviews/tesla-79-promises-to-transmit-force-new-york-times-july-11-1935/ |url-status=live }}</ref>

Tesla claimed to have developed his own physical principle regarding matter and energy that he started working on in 1892,{{sfn|O'Neill|1944|p=247}} and in 1937, at age 81, claimed in a letter to have completed a "dynamic theory of gravity" that " put an end to idle speculations and false conceptions, as that of curved space". He stated that the theory was "worked out in all details" and that he hoped to soon give it to the world.<ref> {{Webarchive|url=https://web.archive.org/web/20110724105436/http://www.tesla.hu/tesla/articles/19370710.doc |date=24 July 2011 }} downloadable from http://www.tesla.hu {{Webarchive|url=https://web.archive.org/web/20181225022943/http://tesla.hu/ |date=25 December 2018 }}</ref> Further elucidation of his theory was never found in his writings.{{sfn|Cheney|2001|p=309}}

=== On society ===
{{Eugenics sidebar}}
Tesla is widely considered by his biographers to have been a ] in philosophical outlook.{{sfn|Jonnes|2004|p=154}}<ref>{{cite book |title=Innovation: The Lessons of Nikola Tesla |year=2008 |publisher=Blue Eagle |isbn=978-987-651-009-7 |page=43 |first1=Peter |last1=Belohlavek |first2=John W |last2=Wagner |quote=This was Tesla: a scientist, philosopher, humanist, and ethical man of the world in the truest sense.}}</ref> This did not preclude Tesla, like many of his era, from becoming a proponent of an imposed ] version of ].

Tesla expressed the belief that human "pity" had come to interfere with the natural "ruthless workings of nature". Though his argumentation did not depend on a concept of a "master race" or the inherent superiority of one person over another, he advocated for eugenics. In a 1937 interview he stated:


{{blockquote|...&nbsp;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&nbsp;... 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.<ref>{{cite web |url=https://www.pbs.org/tesla/res/res_art11.html |title=A Machine to End War |date=February 1937 |publisher=Public Broadcasting Service |access-date=23 November 2010 |archive-date=20 January 2022 |archive-url=https://web.archive.org/web/20220120214740/https://www.pbs.org/tesla/res/res_art11.html |url-status=live }}</ref>}}
Tesla is widely considered by his biographers as a ] regarding his worldview.<ref name=Jonnes />{{Rp|154}}<ref>{{cite book |title=The Tesla Papers |year=2000 |publisher=Adventures Unlimited Press |isbn=978-0-932813-86-2 |page=15 | editor-first =David Hatcher |last=Childress |quote=His idealism and humanism left him with little stomach for the world of industrial and financial intrigue.}}</ref><ref>{{cite book |title=Innovation: The Lessons of Nikola Tesla |year=2008 |publisher=Blue Eagle |isbn=978-987-651-009-7 |page=43 |first1=Peter |last1=Belohlavek |first2=John W |last2=Wagner |quote=This was Tesla: a scientist, philosopher, humanist, and ethical man of the world in the truest sense.}}</ref><ref>{{cite book |title=Edison's Concrete Piano: Flying Tanks, Six-Nippled Sheep, Walk-On-Water Shoes, and 12 Other Flops From Great Inventors |year=2009 |publisher=ECW Press |isbn=978-1-55490-551-5 |first=Judy |last=Wearing |quote=Tesla, the unselfish humanist he was, would roll over in his grave.}}</ref><ref>{{cite book |title=Wizard: the life and times of Nikola Tesla: biography of a genius |year=1996 |publisher=Citadel Press |isbn=978-0-8065-1960-9 |page=506 |first=Marc J |last=Seifer |quote=Frank Jenkins, "Nikola Tesla: The Man, Engineer, Inventor, Humanist and Innovator," in Nikola Tesla: Life and Work of a Genius (Belgrade: Yugoslav Society for the Promotion of Scientific Knowledge, 1976), pp. 10–21.}}</ref>


In 1926, Tesla commented on the ills of the social subservience of women and the struggle of women toward ], and indicated that humanity's future would be run by "]". He believed that women would become the dominant sex in the future.<ref>Kennedy, John B., " {{Webarchive|url=https://web.archive.org/web/20110606023652/http://www.tfcbooks.com/tesla/1926-01-30.htm |date=6 June 2011 }}, An interview with Nikola Tesla." ], 30 January 1926.</ref>
Tesla made predictions about the relevant issues of a post-World War I environment in a printed article, "Science and Discovery are the great Forces which will lead to the Consummation of the War" (20 December 1914).<ref>{{cite web |last=Tesla |first=Nikola |title=Science and Discovery are the great Forces which will lead to the Consummation of the War |url=http://www.rastko.rs/rastko/delo/10832 |publisher=Rastko |accessdate=17 July 2012}}</ref> Tesla believed that the ] was not a remedy for the times and issues.{{Citation needed | date=June 2012}}


Tesla made predictions about the relevant issues of a post-World War I environment in a printed article entitled "Science and Discovery are the great Forces which will lead to the Consummation of the War" (20 December 1914).<ref>{{cite web |last=Tesla |first=Nikola |title=Science and Discovery are the great Forces which will lead to the Consummation of the War |url=http://www.rastko.rs/rastko/delo/10832 |publisher=Rastko |access-date=17 July 2012 |archive-date=2 April 2015 |archive-url=https://web.archive.org/web/20150402053438/http://www.rastko.rs/rastko/delo/10832 |url-status=live }}</ref> Tesla believed that the ] was not a remedy for the times and issues.<ref name="tesla1" />{{better source needed|date=January 2022}}
=== Views on religion ===
Tesla was raised as an ]. Later in his life, he did not consider himself to be a "believer in the orthodox sense," and opposed ].<ref name="autogenerated1937">{{cite web |title=A Machine to End War |url=http://www.pbs.org/tesla/res/res_art11.html |publisher=PBS.org |accessdate=27 July 2012 |author=Nikola Tesla |coauthors=by Nikola Tesla as told to George Sylvester Viereck |date=February 1937}}</ref> Despite this, he had a profound respect for both ] and ].<ref name="tesla1" /><ref name="autogenerated1937" />


=== On religion ===
In his article, "The Problem of Increasing Human Energy," published in 1900, Tesla stated: {{quote|For ages this idea has been proclaimed in the consummately wise teachings of religion, probably not alone as a means of insuring peace and harmony among men, but as a deeply founded truth. The Buddhist expresses it in one way, the Christian in another, but both say the same: We are all one.<ref>{{cite web |last=Tesla |first=Nikola |title=THE PROBLEM OF INCREASING HUMAN ENERGY |url=http://www.tfcbooks.com/tesla/1900-06-00.htm |publisher=Century Illustrated Magazine |accessdate=15 August 2012}}</ref>}} However, his religious views remain uncertain due to other statements that he made.<ref>{{cite book |title=Alien Interview |year=2008 |publisher=New York Herald Tribune |isbn=978-0-615-20460-4 |author=Nikola Tesla |editor=Lawrence R. Spencer |accessdate=31 July 2012 |page=303 |date=11 September 1932 |quote=It might as well be said that God has properties. He has not, but only attributes and these are of our own making.}}</ref><ref>{{cite book |title=Radio's 100 men of science: biographical narratives of pathfinders in electronics and television |year=1944 |publisher=Harper & Brothers |pages=122–123 |author=Orrin Elmer Dunlap |edition=2 |quote=In one of his last interviews with this author, Tesla in his eighties still dreamed of power transmission by radio.&nbsp;... "Religion is simply an ideal" . "It is an ideal force that tends to free the human being from material bonds. I do not believe that matter and energy are interchangeable, any more than are the body and soul. There is just so much matter in the universe and it cannot be destroyed. As I see life on this planet, there is no individuality. It may sound ridiculous to say so, but I believe each person is but a wave passing through space, ever-changing from minute to minute as it travels along, finally, some day, just becoming dissolved."}}</ref><ref>{{cite book |title=Nikola Tesla |publisher=FECHA |url=http://fecha.org/tesla.htm |accessdate=31 July 2012}}</ref> For example, in his article, "A Machine to End War", published in 1937, Tesla stated: {{quote|There is no conflict between the ideal of religion and the ideal of science, but science is opposed to theological dogmas because science is founded on fact. To me, the universe is simply a great machine which never came into being and never will end. The human being is no exception to the natural order. Man, like the universe, is a machine. Nothing enters our minds or determines our actions which is not directly or indirectly a response to stimuli beating upon our sense organs from without. Owing to the similarity of our construction and the sameness of our environment, we respond in like manner to similar stimuli, and from the concordance of our reactions, understanding is born. In the course of ages, mechanisms of infinite complexity are developed, but what we call "soul" or "spirit," is nothing more than the sum of the functionings of the body. When this functioning ceases, the "soul" or the "spirit" ceases likewise.<ref name="autogenerated1937" />}}
Tesla was raised an ]. Later in life he did not consider himself to be a "believer in the orthodox sense", said he opposed ], and said "Buddhism and Christianity are the greatest religions both in number of disciples and in importance."<ref name="Viereck1937">{{cite web |title=A Machine to End War |url=https://www.pbs.org/tesla/res/res_art11.html |publisher=PBS.org |access-date=27 July 2012 |last=Tesla |first=Nikola |editor=George Sylvester Viereck |date=February 1937 |archive-date=20 January 2022 |archive-url=https://web.archive.org/web/20220120214740/https://www.pbs.org/tesla/res/res_art11.html |url-status=live }}</ref> He also said "To me, the universe is simply a great machine which never came into being and never will end" and "what we call 'soul' or 'spirit,' is nothing more than the sum of the functionings of the body. When this functioning ceases, the 'soul' or the 'spirit' ceases likewise."<ref name="Viereck1937" />


== Literary works == == Literary works ==
Tesla wrote a number of books and articles for magazines and journals.<ref>{{cite web |title=Nikola Tesla Bibliography |url=http://www.tfcbooks.com/tesla/bibliography.htm |publisher=21st Century Books |accessdate=21 April 2011}}</ref> Among his books are '']'', compiled and edited by Ben Johnston; '']'', compiled and edited by ]; and ''The Tesla Papers''. Tesla wrote a number of books and articles for magazines and journals.<ref>{{cite web |title=Nikola Tesla Bibliography |url=http://www.tfcbooks.com/tesla/bibliography.htm |publisher=21st Century Books |access-date=21 April 2011 |archive-date=27 September 2015 |archive-url=https://web.archive.org/web/20150927044514/http://www.tfcbooks.com/tesla/bibliography.htm |url-status=live }}</ref> Among his books are '']'', compiled and edited by Ben Johnston in 1983 from a series of 1919 magazine articles by Tesla which were republished in 1977; '']'' (1993), compiled and edited by ]; and ''The Tesla Papers''.


Many of Tesla's writings are freely available on the web,<ref>{{cite web |title=Nikola Tesla Information Resource |url=http://www.tfcbooks.com/ |publisher=21st Century Books |accessdate=21 April 2011}}</ref><ref>{{cite web |title=Selected Tesla writings |url=http://www.tfcbooks.com/tesla/contents.htm |publisher=21st Century Books |accessdate=21 April 2011}}</ref><ref>{{gutenberg author|id=Nikola+Tesla|name=Nikola Tesla}}</ref> including the article "The Problem of Increasing Human Energy," published in '']'' in 1900,<ref>{{cite journal |last=Tesla |first=Nikola |title=The Problem of Increasing Human Energy |journal=] |year=1900 |volume=60 (n.s. v. 38) |issue=1900 May–Oct |url=http://babel.hathitrust.org/cgi/ptid=mdp.39015013530053;q1=increasing%20human;start=1;size=100;page=root;view=image;seq=193;num=175 |accessdate=21 April 2011 |page=175}}</ref><ref>{{cite web |title=THE PROBLEM OF INCREASING HUMAN ENERGY |url=http://www.tfcbooks.com/tesla/1900-06-00.htm |publisher=Twenty-First Century Books |accessdate=21 April 2011}}</ref> and the article "Experiments With Alternate Currents Of High Potential And High Frequency," published in his book ''Inventions, Researches and Writings of Nikola Tesla''.<ref>{{cite web |last=Tesla |first=Nikola |title=The Project Gutenberg eBook, Experiments with Alternate Currents of High Potential and High Frequency, by Nikola Tesla |url=http://www.gutenberg.org/files/13476/13476-h/13476-h.htm |publisher=] |accessdate=21 April 2011}}</ref><ref>{{cite web |last=Tesla |first=Nikola |title=EXPERIMENTS WITH ALTERNATE CURRENTS OF HIGH POTENTIAL AND HIGH FREQUENCY |url=http://www.tfcbooks.com/tesla/1892-02-03.htm |publisher=Twenty-First Century Books |accessdate=21 April 2011}}</ref> Many of Tesla's writings are freely available online,<ref>{{cite web|title=Selected Tesla writings|work=Nikola Tesla Information Resource|url=http://www.tfcbooks.com/tesla/contents.htm|access-date=15 March 2008|archive-url=https://web.archive.org/web/20090130031901/http://tfcbooks.com/tesla/contents.htm|archive-date=30 January 2009|url-status=dead}}</ref> including the article "The Problem of Increasing Human Energy", published in '']'' in 1900,<ref>{{cite web |title=THE PROBLEM OF INCREASING HUMAN ENERGY |url=http://www.tfcbooks.com/tesla/1900-06-00.htm |publisher=Twenty-First Century Books |access-date=21 April 2011 |archive-date=20 November 2019 |archive-url=https://web.archive.org/web/20191120001402/http://www.tfcbooks.com/tesla/1900-06-00.htm |url-status=live }}</ref> and the article "Experiments with Alternate Currents of High Potential and High Frequency", published in his book ''Inventions, Researches and Writings of Nikola Tesla''.<ref>{{cite book |last=Tesla |first=Nikola |title=The Project Gutenberg eBook, Experiments with Alternate Currents of High Potential and High Frequency, by Nikola Tesla |url=https://www.gutenberg.org/files/13476/13476-h/13476-h.htm |publisher=] |access-date=21 April 2011 |archive-date=16 September 2011 |archive-url=https://web.archive.org/web/20110916122641/http://www.gutenberg.org/files/13476/13476-h/13476-h.htm |url-status=live }}</ref><ref>{{cite web |last=Tesla |first=Nikola |title=EXPERIMENTS WITH ALTERNATE CURRENTS OF HIGH POTENTIAL AND HIGH FREQUENCY |url=http://www.tfcbooks.com/tesla/1892-02-03.htm |publisher=Twenty-First Century Books |access-date=21 April 2011 |archive-date=19 September 2015 |archive-url=https://web.archive.org/web/20150919045738/http://www.tfcbooks.com/tesla/1892-02-03.htm |url-status=live }}</ref>


== Legacy and honors == == Legacy and honors ==
{{See also|Nikola Tesla in popular culture}} {{See also|Nikola Tesla in popular culture|List of things named after Nikola Tesla|List of Nikola Tesla patents}}
]'' for 20 July 1931.]] ] (], Belgrade)]]
In 1952, following pressure from Tesla's nephew, influential Yugoslav politician {{ill|Sava Kosanović|sr|Sava Kosanović (političar)}}, Tesla's entire estate was shipped to Belgrade in 80 trunks marked N.T. In 1957, Kosanović's secretary Charlotte Muzar transported Tesla's ashes from the United States to Belgrade. The ashes are displayed in a gold-plated sphere on a marble pedestal in the ].<ref>{{cite web |title=Urn with Tesla's ashes |url=http://www.tesla-museum.org/meni_en/muzej/3.htm |publisher=Tesla Museum |access-date=16 September 2012 |url-status=dead |archive-url=https://web.archive.org/web/20120825230422/http://www.tesla-museum.org/meni_en/muzej/3.htm |archive-date=25 August 2012 }}</ref> Nikola Tesla's Archive consists of over 160,000 original documents and is included in UNESCO ].<ref>{{Cite news |title=Nikola Tesla's Archive |url=https://www.unesco.org/en/memory-world/nikola-teslas-archive |archive-url=http://web.archive.org/web/20241203015718/https://www.unesco.org/en/memory-world/nikola-teslas-archive |archive-date=2024-12-03 |access-date=2024-12-24 |language=en}}</ref><ref>{{Cite web |title=Archive – Nikola Tesla Museum |url=https://tesla-museum.org/en/legacy/archive/ |access-date=2024-12-24 |language=en-US}}</ref>
] in Belgrade, Serbia.]]
] banknote.]]


Tesla obtained around 300 patents worldwide for his inventions.<ref name="sarboh">{{cite web |url=http://www.tesla-symp06.org/papers/Tesla-Symp06_Sarboh.pdf |title=Nikola Tesla's Patents |first=Snežana |last=Šarboh |date=18–20 October 2006 |work=Sixth International Symposium Nikola Tesla |location=Belgrade, Serbia |page=6 |archive-url=https://web.archive.org/web/20071030134331/http://www.tesla-symp06.org/papers/Tesla-Symp06_Sarboh.pdf |archive-date=30 October 2007 |access-date=8 October 2010 |ref=sarbo}}</ref> Some of Tesla's patents are not accounted for, and various sources have discovered some that have lain hidden in patent archives. There are a minimum of 278 known patents<ref name="sarboh" /> issued to Tesla in 26 countries. Many of Tesla's patents were in the United States, ], and Canada, but many other patents were approved in countries around the globe.{{sfn|Cheney|2001|p=62}} Many inventions developed by Tesla were not put into patent protection.{{Cn|date=October 2024}}
Tesla's legacy has endured in books, films, radio, TV, music, live theater, comics and video games. The lack of recognition received during his own lifetime has cast him as 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.
* On Tesla's 75th birthday in 1931, ] put him on its cover.<ref>{{cite news |title=Nikola Tesla {{!}} 20 July 1931|url=http://www.time.com/time/covers/0,16641,19310720,00.html|work=Time|accessdate=2 July 2012}}</ref> The cover caption "All the world's his power house" noted his contribution to ]. He received congratulatory letters from more than 70 pioneers in science and engineering, including Albert Einstein.<ref>{{cite web |url=http://www.teslasociety.com/time.jpg |title=Time front cover, Vol XVIII, No. 3, 20 July 1931 |accessdate=10 September 2012}}</ref>
* The Tesla Society, founded in 1956.<ref>{{harvnb|Seifer|2001|p=464}}</ref>
* ], a 26 kilometer-wide crater on the far side of the moon.<ref name="Minorplanet">{{cite book |title=Dictionary of minor planet names |last=Schmadel |first=Lutz D. |year=2003 |publisher=Springer |isbn=3-540-00238-3 |page=183 |url=http://books.google.com/?id=KWrB1jPCa8AC |accessdate=28 November 2010}}</ref>
* ], a minor planet.<ref name="Minorplanet" />
* ], the largest power plant in Serbia.
* ], electrotechnical conglomerate in the former Czechoslovakia.
* ], an electric car company.<ref>{{cite web |url=http://www.teslamotors.com/learn_more/why_tesla.php |title=Why the Name "Tesla?" |publisher=Tesla Motors |accessdate=10 June 2008 |archiveurl=http://web.archive.org/web/20071016044752/http://www.teslamotors.com/learn_more/why_tesla.php |archivedate=16 October 2007}}</ref>
* The ].<ref>{{cite web |url=http://www.airport-desk.com/airports/europe/serbia/belgrade-nikola-tesla-airport.html |title=Belgrade Nikola Tesla Airport |publisher=airport-desk.com |accessdate=29 November 2010}}</ref>
* The ]<ref>{{cite web |last=Vujovic |first=Dr. Ljubo |title=Tesla Biography NIKOLA TESLA THE GENIUS WHO LIT THE WORLD |url=http://www.teslasociety.com/biography.htm |publisher=Tesla Memorial Society of New York |accessdate=30 April 2012}}</ref>
* The ] Archive in ]<ref>{{cite web |url=http://www.unesco.org/new/en/communication-and-information/flagship-project-activities/memory-of-the-world/homepage/ |title=Memory of the World &#124; United Nations Educational, Scientific and Cultural Organization |publisher=UNESCO |accessdate=10 September 2012}}</ref><ref>http://www.teslasociety.com/archive.htm</ref>
* 10 July, National day of Nikola Tesla in Croatia

=== Plaques and memorials ===
]. The placement of the sign was due to the efforts of the Croatian Club of New York in cooperation with New York City officials, and Dr Ljubo Vujovic of the Tesla Memorial Society of New York.<ref> Tesla Memorial Society of New York. Retrieved 21 September 2014.</ref>]]
* The Nikola Tesla Memorial Centre in Smiljan, Croatia, opened in 2006. It features a statue of Tesla designed by sculptor Mile Blažević.<ref name="tsbirthplace">{{cite web |title=Pictures of Tesla's home in Smiljan, Croatia and his father's church after rebuilding. |url=http://www.teslasociety.com/birthplace.htm |publisher=Tesla Memorial Society of NY |accessdate=22 May 2013}}</ref><ref name="MemorialCentreSmiljan">{{cite web |url=http://www.mcnikolatesla.hr/english.html |title=Nikola Tesla Memorial Centre |publisher=MCNikolaTesla.hr |accessdate=27 May 2011}}</ref><ref name="gospichr">{{cite web |url=http://www.mcnikolatesla.hr/ |title=Memorijalni centar 'Nikola Tesla' Smiljan |publisher=Mcnikolatesla.hr |language=Croatian |accessdate=25 January 2014}}</ref>
* On 7 July 2006, on the corner of Masarykova and Preradovićeva streets in the ] area in Zagreb, Croatia, a monument of Tesla was unveiled. This monument was designed by ] in 1952 and was transferred from the Zagreb-based ] where it had spent previous decades.<ref>{{cite web |title=Tesla Timeline |url=http://www.teslauniverse.com/nikola-tesla-timeline-1956-sava-kosanovic-dies |publisher=Tesla Universe |accessdate=3 July 2012}}</ref><ref>{{cite web |title=Weekly Bulletin |url=http://us.mfa.hr/Portals/US/Embassy%20of%20the%20Republic%20of%20Croatia%20(Weekly%20Bulletin%20-%20Vol.%203,%20Issue%2015).pdf |publisher=Embassy of the Republic of Croatia |accessdate=3 July 2012}}</ref>
* A monument to Tesla was established at ], New York. This monument portraying Tesla reading a set of notes was sculpted by ]. It was presented to the United States by Yugoslavia in 1976 and is an identical copy of the monument standing in front of the ].
* A monument of Tesla standing on a portion of an alternator, was established at ] in Niagara Falls, ]. 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, ], and designed by Les Drysdale of ].<ref>{{cite web |title=Tmsusa |url=http://www.teslasociety.com/tmsusa.htm |publisher=Tesla Memorial Society of NY |accessdate=3 July 2012}}</ref><ref>{{cite web |title=Niagara Falls |url=http://www.teslasociety.org/niagarafalls.html |publisher=Tesla Memorial Society of NY |accessdate=3 July 2012}}</ref> Drysdale's design was the winning design from an international competition.<ref>{{cite web |first1=Andrew|last1= Roberts|first2= Marc|last2= Kennedy|first3=Alex|last3= Nequest |title=Tesla Honored With Niagara Falls Monument |url=http://www.ieee.ca/canrev/cr53/CR53_Tesla_Monument.pdf |publisher=IEEE Canada |accessdate=4 July 2012}}</ref>
* In 2012, Jane Alcorn, president of the nonprofit group The ], and Matthew Inman, creator of web cartoon '']'', raised a total of $2,220,511&nbsp;– $1,370,511 from a campaign and $850,000 from a New York State grant—to buy the property where Wardenclyffe Tower once stood and eventually turn it into a museum.<ref>{{cite news |last=Frum |first=Larry |title=Backers raise cash for Tesla museum honoring 'cult hero' |url=http://www.cnn.com/2012/08/21/tech/innovation/tesla-museum-campaign/index.html?hpt=hp_bn5 |publisher=CNN |accessdate=27 August 2012 |date=21 August 2012}}</ref><ref>{{cite web |title=Let's Build a Goddamn Tesla Museum |url=http://www.indiegogo.com/teslamuseum |publisher=indiegogo |accessdate=5 October 2012}}</ref> The group began negotiations to purchase the ] property from Agfa Corporation in October 2012.<ref>{{cite news |url=http://www.nytimes.com/2012/10/06/nyregion/group-buying-long-island-estate-for-tesla-memorial.html |accessdate=12 May 2013 |title=Group Buying Long Island Estate for Tesla Memorial |work=The New York Times |date=5 October 2012 |last=Broad |first=William}}</ref> The purchase was completed in May 2013.<ref>{{cite news |url=http://www.latimes.com/business/technology/la-fi-tn-tesla-museum-campaign-purchase-lab-20130509,0,4996501.story |accessdate=12 May 2013 |title=Web campaign to build a Tesla museum succeeds in purchasing lab |date=9 May 2013 |work=Los Angeles Times |last=Rodriguez |first=Salvador}}</ref>
* A commemorative plaque honoring Nikola Tesla was installed on the façade of the New Yorker Hotel by the IEEE.<ref>{{cite web |title=A hotel's unique direct current (dc) system |url=http://www.ieee.org/organizations/pes/public/2006/jan/peshistory.html |publisher=IEEE |accessdate=16 July 2012}}</ref>
* An intersection named after Tesla, Nikola Tesla Corner, is at the intersection of ] and ] in ], ].
* A bust and plaque honoring Tesla is outside the ] (formerly known as Trinity Chapel) at 20 West 26th Street in New York City.<ref>{{cite web |title=Edith Wharton was unhappy here |url=http://lostnewyorkcity.blogspot.com/2012/11/edith-wharton-was-unhappy-here.html |publisher=Lost City |accessdate=10 July 2014}}</ref>
* A full-size, crowdfunded statue honoring Tesla with free Wi-Fi and a time capsule (to be opened on the 100th anniversary of Tesla's death - 7 Jan 2043) was unveiled on December 7, 2013 in Palo Alto, California (260 Sheridan Avenue).<ref>{{cite web |title=http://venturebeat.com/2013/12/07/heres-a-first-look-at-the-tesla-statue-in-palo-alto/ |publisher=VentureBeat|accessdate=18 October 2014}}</ref>


== See also == == See also ==
* {{annotated link|Atmospheric electricity}}
* ]
* {{annotated link|Michael Faraday}}
* ]
* {{annotated link|Charles Proteus Steinmetz}}
* {{annotated link|Telluric current}}

== Notes ==
'''Footnotes'''
{{Notelist}}

'''Citations'''
{{Reflist}}


== References == == References ==
=== Notes ===
{{Reflist|30em}}

=== Sources ===
{{Refbegin|30em}} {{Refbegin|30em}}
* {{cite book |title=Wizard: the life and times of Nikola Tesla: biography of a genius |last=Seifer |first=Marc J |year=2001 |publisher=Citadel |isbn=978-0-8065-1960-9 |url=http://books.google.co.uk/books?id=h2DTNDFcC14C |ref=harv}} * {{cite book |last=Burgan |first=Michael |title=Nikola Tesla: Inventor, Electrical Engineer |year=2009 |publisher=] |location=Mankato, Minnesota |isbn=978-0-7565-4086-9 |url=https://books.google.com/books?id=PW06qF-dj2IC }}
* {{cite book |title=Prodigal Genius: The Life of Nikola Tesla |last=O'Neill |first=John J |year=2007 |publisher=Book Tree |isbn=978-1-60206-743-1 |url=http://books.google.co.uk/books?id=-cHJQL8qCEMC |ref=harv}} * {{cite book|last=Carlson|first=W. Bernard|title=Tesla: Inventor of the Electrical Age|url=https://books.google.com/books?id=5I5c9j8BEn4C|year=2013|publisher=]|isbn=978-1-4008-4655-9|access-date=2 June 2015|archive-date=5 August 2023|archive-url=https://web.archive.org/web/20230805044626/https://books.google.com/books?id=5I5c9j8BEn4C|url-status=live}}
* {{cite book |last=Cheney |first=Margaret |title=Tesla: Man Out of Time |origyear=1981 |url=http://books.google.com/?id=ti2Jt7XarzMC |year=2001 |publisher=] |ref=harv |isbn=978-0-7432-1536-7}} * {{cite book|last=Cheney|first=Margaret|title=Tesla: Man Out of Time|url=https://books.google.com/books?id=HIuK7iLO9zgC|year=2011|publisher=Simon & Schuster|isbn=978-1-4516-7486-6|access-date=13 December 2015|archive-date=23 March 2024|archive-url=https://web.archive.org/web/20240323124618/https://books.google.com/books?id=HIuK7iLO9zgC|url-status=live}}
* {{cite book |title=Tesla, Master of Lightning |last1=Cheney |first1=Margaret |last2=Uth |first2=Robert |last3=Glenn |first3=Jim |year=1999 |publisher=Barnes & Noble Books |isbn=978-0-7607-1005-0 |url=http://books.google.co.uk/books?id=3W6_h6XG6VAC |ref=harv}} * {{cite book |last=Cheney |first=Margaret |title=Tesla: Man Out of Time |orig-year=1981 |url=https://books.google.com/books?id=ti2Jt7XarzMC |year=2001 |publisher=] |isbn=978-0-7432-1536-7 |access-date=14 May 2020 |archive-date=23 March 2024 |archive-url=https://web.archive.org/web/20240323124620/https://books.google.com/books?id=ti2Jt7XarzMC |url-status=live }}
* {{cite book |last1=Cheney |first1=Margaret |last2=Uth |first2=Robert |last3=Glenn |first3=Jim |title=Tesla, Master of Lightning |year=1999 |publisher=] |isbn=978-0-7607-1005-0 |url=https://books.google.com/books?id=3W6_h6XG6VAC |access-date=21 June 2015 |archive-date=23 March 2024 |archive-url=https://web.archive.org/web/20240323124632/https://books.google.com/books?id=3W6_h6XG6VAC |url-status=live }}
* {{cite book |url=http://books.google.co.uk/books?id=P0CSxB2aHMcC |title=Strange Brains and Genius: The Secret Lives Of Eccentric Scientists And Madmen |last=Pickover |first=Clifford A. |publisher=HarperCollins |year=1999 |ref=harv}}
* {{cite book |last1=Cooper |first1=Christopher |title=The truth about Tesla : the myth of the lone genius in the history of innovation |date=2015 |location=New York |isbn=978-1-63106-030-4 |publisher=Race Point Publishing}}
* {{cite book |title=The fantastic inventions of Nikola Tesla |last=Childress |first=David |year=1993 |publisher=Adventures Unlimited Press |isbn=978-0-932813-19-0 |url=http://books.google.co.uk/books?id=fXB0fm-QqLMC |ref=harv}}
* {{cite book |title=Empires of Light: Edison, Tesla, Westinghouse, and the Race to Electrify the World |last=Jonnes |first=Jill |year=2004 |publisher=Random House Trade Paperbacks |isbn=978-0-375-75884-3 |url=http://books.google.co.uk/books?id=BKX5UYWzVyQC |ref=harv}} * {{cite book|last=Dommermuth-Costa|first=Carol|title=Nikola Tesla: A Spark of Genius|url=https://books.google.com/books?id=kFFWipanqsoC|year=1994|publisher=]|isbn=978-0-8225-4920-8|access-date=13 December 2015|archive-date=23 March 2024|archive-url=https://web.archive.org/web/20240323125136/https://books.google.com/books?id=kFFWipanqsoC|url-status=live}}
* {{cite book |last=Jonnes |first=Jill |title=Empires of Light: Edison, Tesla, Westinghouse, and the Race to Electrify the World |year=2004 |publisher=] Trade Paperbacks |isbn=978-0-375-75884-3 |url=https://books.google.com/books?id=BKX5UYWzVyQC |access-date=13 December 2015 |archive-date=23 March 2024 |archive-url=https://web.archive.org/web/20240323125210/https://books.google.com/books?id=BKX5UYWzVyQC |url-status=live }}
* {{cite book |last=Bock-Luna |first=Birgit |url=http://books.google.co.uk/books?id=c6UGrE5dUzQC |title=The past in exile: Serbian long-distance nationalism and identity in the wake of the Third Balkan War |year=2007 |publisher=LIT Verlag Münster |isbn=978-3-8258-9752-9 |ref=harv}}
* {{cite book|last=Klooster|first=John W.|title=Icons of Invention: The Makers of the Modern World from Gutenberg to Gates|url=https://books.google.com/books?id=WKuG-VIwID8C|year=2009|publisher=]|isbn=978-0-313-34743-6|access-date=13 December 2015|archive-date=23 March 2024|archive-url=https://web.archive.org/web/20240323125138/https://books.google.com/books?id=WKuG-VIwID8C|url-status=live}}
* {{cite book |last=Van Riper |first=A. Bowdoin |url=http://books.google.co.uk/books?id=ABtJPIcVtBoC |title=A Biographical Encyclopedia of Scientists and Inventors in American Film and TV since 1930 |year=2011 |publisher=Scarecrow Press |isbn=978-0-8108-8128-0 |ref=harv}}
* {{cite book |last=O'Neill |first=John J. | authorlink = John Joseph O'Neill (journalist) |title=Prodigal Genius: The Life of Nikola Tesla |year=1944 |publisher=Ives Washburn |location=New York |isbn=0-914732-33-1 |url=https://www.rastko.rs/istorija/tesla/oniell-tesla.html |access-date=10 July 2024 |archive-date=3 December 2023 |archive-url=https://web.archive.org/web/20231203084239/https://www.rastko.rs/istorija/tesla/oniell-tesla.html |url-status=live }} (see also '']''; also {{ISBN|1-59605-713-0}}; reprinted 2007 by Book Tree, {{ISBN|978-1-60206-743-1}})
* Lomas, Robert, ''''. Lecture to South Western Branch of Instititute of Physics.
* {{cite book |last=Pickover |first=Clifford A. |url=https://books.google.com/books?id=P0CSxB2aHMcC |title=Strange Brains and Genius: The Secret Lives Of Eccentric Scientists And Madmen |publisher=] |year=1999 |isbn=978-0-688-16894-0 |access-date=13 December 2015 |archive-date=23 March 2024 |archive-url=https://web.archive.org/web/20240323125210/https://books.google.com/books?id=P0CSxB2aHMcC |url-status=live }}
* ], ''The Inventions, Researches, and Writings of Nikola Tesla'', New York: The Electrical Engineer, 1894 (3rd Ed.); reprinted by Barnes & Noble, 1995
* {{cite book|last1=Petešić|first1=Ćiril|title=Genij s našeg kamenjara: život i djelo Nikole Tesle|trans-title=The genius from our rocks: life and work of Nikola Tesla|year=1976|publisher=Školske novine|location=Zagreb|language=hr|oclc=36439558}}
* Penner, John R.H. '''', corrupted version of "]."
* {{cite book |last=Seifer |first=Marc J. |title=Wizard: the life and times of Nikola Tesla: biography of a genius |year=2001 |publisher=Citadel |isbn=978-0-8065-1960-9 |url=https://books.google.com/books?id=h2DTNDFcC14C |access-date=13 December 2015 |archive-date=23 March 2024 |archive-url=https://web.archive.org/web/20240323125147/https://books.google.com/books?id=h2DTNDFcC14C |url-status=live }}
* Pratt, H., ''Nikola Tesla 1856–1943'', ''Proceedings of the IRE'', Vol. 44, September 1956.
* {{cite book|last=Seifer|first=Marc J.|title=Wizard: The Life And Times Of Nikola Tesla|url=https://books.google.com/books?id=DzMR8x_rbPgC|year=1998|publisher=Citadel|isbn=978-0-8065-3556-2|access-date=16 March 2016|archive-date=23 March 2024|archive-url=https://web.archive.org/web/20240323125351/https://books.google.ro/books?id=DzMR8x_rbPgC&redir_esc=y|url-status=live}}
* ], , Resonance, March 2007.
* {{cite book |last=Van Riper |first=A. Bowdoin |url=https://books.google.com/books?id=ABtJPIcVtBoC |title=A Biographical Encyclopedia of Scientists and Inventors in American Film and TV since 1930 |year=2011 |publisher=Scarecrow Press |isbn=978-0-8108-8128-0 }}
* Weisstein, Eric W., ''''. Eric Weisstein's World of Science.
* {{cite book | title = Nikola Tesla and the Graz Tech | editor-first1 = Uwe | editor-last1 = Schichler | editor-first2 = Josef W. | editor-last2 = Wohinz | first = Josef W. | last = Wohinz | chapter = Nikola Tesla: Milestones in his life | publisher = Graz University of Technology/Library and Archive | year = 2019 | doi = 10.3217/978-3-85125-687-1 | volume = 7 EN | isbn = 978-3-85125-688-8 }}
* Dimitrijevic, Milan S., ''Belgrade Astronomical Observatory Historical Review''. Publ. Astron. Obs. Belgrade, 162–170. Also, ''Srpski asteroidi, ''. Astronomski magazine.
* Roguin, Ariel, ''Historical Note: Nikola Tesla: The man behind the magnetic field unit''. J. Magn. Reson. Imaging 2004;19:369–374. 2004 Wiley-Liss, Inc.
* Sellon, J. L., ''The impact of Nikola Tesla on the cement industry''. Behrent Eng. Co., Wheat Ridge, Colorado. Cement Industry Technical Conference. 1997. XXXIX Conference Record., 1997 IEEE/PC. Page(s) 125–133.
* Valentinuzzi, M.E., ''Nikola Tesla: why was he so much resisted and forgotten?'' Inst. de Bioingenieria, Univ. Nacional de Tucuman; Engineering in Medicine and Biology Magazine, IEEE. July/August 1998, 17:4, pp.&nbsp;74–75.
* Secor, H. Winfield, ''Tesla's views on Electricity and the War'', Electrical Experimenter, Volume 5, Number 4 August 1917.
* Florey, Glen, ''Tesla and the Military''. ''Engineering'' 24, 5 December 2000.
* 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.
* Meyl, Konstantin, H. Weidner, E. Zentgraf, T. Senkel, T. Junker, and P. Winkels, ''Experiments to proof the evidence of scalar waves Tests with a Tesla reproduction''. Institut für Gravitationsforschung (IGF), Am Heerbach 5, D-63857 Waldaschaff.
* Anderson, L. I., ''John Stone Stone on Nikola Tesla's Priority in Radio and Continuous Wave Radiofrequency Apparatus''. ], Vol. 1, 1986, pp.&nbsp;18–41.
* Anderson, L. I., ''Priority in Invention of Radio, Tesla v. Marconi''. Antique Wireless Association monograph, March 1980.
* Marincic, A., and D. Budimir, ''Tesla's contribution to radiowave propagation''. Dept. of Electron. Eng., Belgrade Univ. (5th International Conference on Telecommunications in Modern Satellite, Cable and Broadcasting Service, 2001. TELSIKS 2001. pp.&nbsp;327–331 vol.1)
* Page, R. M., ''The Early History of Radar'', ''Proceedings of the IRE'', Volume 50, Number 5 May 1962, (special 50th Anniversary Issue).
* C. Mackechnie Jarvis. ''Nikola Tesla and the induction motor''. 1970 ''Phys. Educ.'' '''5''' 280–287.
* '''' (DOC)
{{Refend}} {{Refend}}


== Further reading == == Further reading ==
{{Library resources box|by=yes}}
=== Books ===

{{Refbegin|40em}}
'''Books'''
* Tesla, Nikola, "]" Parts I through V published in the Electrical Experimenter monthly magazine from February through June 1919. Part VI published October 1919. Reprint edition with introductory notes by Ben Johnson, New York: Barnes and Noble, 1982; also online at '', as ]'', 1919. ISBN 978-0-910077-00-2
{{Refbegin}}
* ] (1894 (1996 reprint)), '']'', Montana: Kessinger. ISBN 978-1-56459-711-3
<!--Keep in alphabetical order by author's surname -->
* ] (1999). '']: Nikola Tesla, forgotten genius of electricity''. London: Headline. ISBN 978-0-7472-7588-6
* Tesla, Nikola, ''],'' Parts I through V published in the ''Electrical Experimenter'' monthly magazine from February through June 1919. Part VI published October 1919. Reprint edition with introductory notes by Ben Johnson, New York: Barnes and Noble, 1982; also online at '' {{Webarchive|url=https://web.archive.org/web/20160202014045/http://www.lucidcafe.com/library/96jul/teslaauto01.html |date=2 February 2016 }}, {{Webarchive|url=https://web.archive.org/web/20160126224720/http://www.tfcbooks.com/special/mi_link.htm |date=26 January 2016 }} as ]'', 1919. {{ISBN|978-0-910077-00-2}}
* Glenn, Jim (1994). '']''. ISBN 978-1-56619-266-8
* Trinkaus, George (2002). ''Tesla: The Lost Inventions'', High Voltage Press. ISBN 978-0-9709618-2-2 * Carlson, W. Bernard (2013). ''Tesla, Inventor of the Electrical Age''. Princeton University Press. {{ISBN|978-0-6910-5776-7}}
* Valone, Thomas (2002). ''Harnessing the Wheelwork of Nature: Tesla's Science of Energy''. ISBN 978-1-931882-04-0 * Glenn, Jim (1994). ''The Complete Patents of Nikola Tesla''. {{ISBN|978-1-56619-266-8}}
* ] (1999). '']: Nikola Tesla, forgotten genius of electricity''. London: Headline. {{ISBN|978-0-7472-7588-6}}
* {{cite book |last1=Peat |first1=F. David|editor1-link=F. David Peat |title=In Search of Nikola Tesla |date=2003 |publisher=Ashgrove |location=Bath |isbn=978-1-85398-117-3 |edition=Revised}}
* ] (1894, 1996 reprint, copyright expired), '']'', includes some lectures, Montana: Kessinger. {{ISBN|978-1-56459-711-3}}
* McNichol, Tom (2006). ''AC/DC The Savage Tale of the First Standards War'', Jossey-Bass. ISBN 978-0-7879-8267-6
* Carlson, W. Bernard (2013). ''Tesla: Inventor of the Electrical Age,'' Princeton University Press. ISBN 978-0-691-05776-7 * McNichol, Tom (2006). ''AC/DC The Savage Tale of the First Standards War'', Jossey-Bass. {{ISBN|978-0-7879-8267-6}}
* {{cite book |last1=Peat |first1=F. David|author-link1=F. David Peat |title=] |date=2002 |publisher=Ashgrove |location=Bath |isbn=978-1-85398-117-3 |edition=Revised}}
* Trinkaus, George (2002). ''Tesla: The Lost Inventions'', High Voltage Press. {{ISBN|978-0-9709618-2-2}}
* Valone, Thomas (2002). ''Harnessing the Wheelwork of Nature: Tesla's Science of Energy''. {{ISBN|978-1-931882-04-0}}
{{Refend}} {{Refend}}


=== Publications === '''Publications'''
{{Refbegin|40em}} {{Refbegin|40em}}
* '']'', American Institute of Electrical Engineers, May 1888. * '']'', American Institute of Electrical Engineers, May 1888.
* '''', Scientific papers and articles written by Tesla and others, spanning the years 1888–1940. * '''', Scientific papers and articles written by Tesla and others, spanning the years 1888–1940.
* '''', The Manufacturer and Builder, January 1892, Vol. 24 * '' {{Webarchive|url=https://web.archive.org/web/20220316114143/http://collections.library.cornell.edu/moa_new/browse.html?frames=1&coll=moa&view=50&root=%2Fmoa%2Fmanu%2Fmanu0024%2F&tif=00119.TIF&cite=http%3A%2F%2Fcdl.library.cornell.edu%2Fcgi-bin%2Fmoa%2Fmoa-cgi%3Fnotisid%3DABS1821-0024-287 |date=16 March 2022 }}'', The Manufacturer and Builder, January 1892, Vol. 24
* Biography: '''', The Century Magazine, November 1893, Vol. 47 * Biography: '' {{Webarchive|url=https://web.archive.org/web/20060509050052/http://cdl.library.cornell.edu/cgi-bin/moa/pageviewer?frames=1&coll=moa&view=50&root=%2Fmoa%2Fcent%2Fcent0047%2F&tif=00592.TIF&cite=http%3A%2F%2Fcdl.library.cornell.edu%2Fcgi-bin%2Fmoa%2Fmoa-cgi%3Fnotisid%3DABP2287-0047-151 |date=9 May 2006 }}'', The Century Magazine, November 1893, Vol. 47
* '''', The Century Magazine, November 1894, Vol. 49 * '' {{Webarchive|url=https://web.archive.org/web/20060509050030/http://cdl.library.cornell.edu/cgi-bin/moa/pageviewer?frames=1&coll=moa&view=50&root=%2Fmoa%2Fcent%2Fcent0049%2F&tif=00924.TIF&cite=http%3A%2F%2Fcdl.library.cornell.edu%2Fcgi-bin%2Fmoa%2Fmoa-cgi%3Fnotisid%3DABP2287-0049-178 |date=9 May 2006 }}'', The Century Magazine, November 1894, Vol. 49
* '''', The Century Magazine, November 1897, Vol. 55 * '' {{Webarchive|url=https://web.archive.org/web/20220316114143/http://collections.library.cornell.edu/moa_new/browse.html?frames=1&coll=moa&view=50&root=%2Fmoa%2Fcent%2Fcent0055%2F&tif=00879.TIF&cite=http%3A%2F%2Fcdl.library.cornell.edu%2Fcgi-bin%2Fmoa%2Fmoa-cgi%3Fnotisid%3DABP2287-0055-194 |date=16 March 2022 }}'', The Century Magazine, November 1897, Vol. 55
{{Refend}} {{Refend}}


=== Journals === '''Journals'''
{{Refbegin|40em}} {{Refbegin|40em}}
* {{cite journal|last=Pavićević |first=Aleksandra|title=From lighting to dust death, funeral and post mortem destiny of Nikola Tesla|journal=Glasnik Etnografskog instituta SANU|year=2014|volume=62|issue=2|pages=125–139|url=http://www.doiserbia.nb.rs/ft.aspx?id=0350-08611402125P|doi=10.2298/GEI1402125P|doi-access=free|hdl=21.15107/rcub_dais_8218|hdl-access=free| issn = 0350-0861 }}
* Carlson, W. Bernard, "Inventor of dreams." '']'', March 2005 Vol. 292 Issue 3 p.&nbsp;78(7).
* Jatras, Stella L., "." '']'', 28 July 2003 Vol. 19 Issue 15 p.&nbsp;9(1) * Carlson, W. Bernard, "Inventor of dreams". '']'', March 2005 Vol. 292 Issue 3 p.&nbsp;78(7).
* Jatras, Stella L., " {{Webarchive|url=https://web.archive.org/web/20111230152239/http://www.thefreelibrary.com/The+genius+of+Nikola+Tesla-a0107043721 |date=30 December 2011 }}". '']'', 28 July 2003 Vol. 19 Issue 15 p.&nbsp;9(1)
* Lawren, B., "Rediscovering Tesla." '']'', March 1988, Vol. 10 Issue 6.
* Rybak, James P., "Nikola Tesla: Scientific Savant." '']'', 1042170X, November 1999, Vol. 16, Issue 11. * Lawren, B., "Rediscovering Tesla". '']'', March 1988, Vol. 10 Issue 6.
* Thibault, Ghislain, "The Automatization of Nikola Tesla: Thinking Invention in the Late Nineteenth Century." '']'', Volume 21, Number 1, Winter 2013, pp.&nbsp;27–52. * Rybak, James P., "Nikola Tesla: Scientific Savant". '']'', 1042170X, November 1999, Vol. 16, Issue 11.
* Thibault, Ghislain, "The Automatization of Nikola Tesla: Thinking Invention in the Late Nineteenth Century". '' {{Webarchive|url=https://web.archive.org/web/20180328103312/https://muse.jhu.edu/article/519919 |date=28 March 2018 }}'', Volume 21, Number 1, Winter 2013, pp.&nbsp;27–52.
* ], "The Inventions, Researches, and Writings of Nikola Tesla", New York: The Electrical Engineer, 1894 (3rd Ed.); reprinted by Barnes & Noble, 1995
* ], , ''Resonance'', March 2007.
* Roguin, Ariel, "Historical Note: Nikola Tesla: The man behind the magnetic field unit". J. Magn. Reson. Imaging 2004;19:369–374. 2004 Wiley-Liss, Inc.
* Sellon, J. L., "The impact of Nikola Tesla on the cement industry". Behrent Eng. Co., Wheat Ridge, Colorado. Cement Industry Technical Conference. 1997. XXXIX Conference Record., 1997 IEEE/PC. Page(s) 125–133.
* Valentinuzzi, M.E., "Nikola Tesla: why was he so much resisted and forgotten?" Inst. de Bioingenieria, Univ. Nacional de Tucuman; Engineering in Medicine and Biology Magazine, IEEE. July/August 1998, 17:4, pp.&nbsp;74–75.
* Secor, H. Winfield, "Tesla's views on Electricity and the War", Electrical Experimenter, Volume 5, Number 4 August 1917.
* Florey, Glen, "Tesla and the Military". ''Engineering'' 24, 5 December 2000.
* 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.
* Meyl, Konstantin, H. Weidner, E. Zentgraf, T. Senkel, T. Junker, and P. Winkels, ''Experiments to proof the evidence of scalar waves Tests with a Tesla reproduction''. Institut für Gravitationsforschung (IGF), Am Heerbach 5, D-63857 Waldaschaff.
* Anderson, L. I., "John Stone Stone on Nikola Tesla's Priority in Radio and Continuous Wave Radiofrequency Apparatus". ], Vol. 1, 1986, pp.&nbsp;18–41.
* Anderson, L. I., "Priority in Invention of Radio, Tesla v. Marconi". Antique Wireless Association monograph, March 1980.
* Marincic, A., and D. Budimir, "Tesla's contribution to radiowave propagation". Dept. of Electron. Eng., Belgrade Univ. (5th International Conference on Telecommunications in Modern Satellite, Cable and Broadcasting Service, 2001. TELSIKS 2001. pp.&nbsp;327–331 vol.1)
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=== Video === '''Video'''
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* {{Webarchive|url=https://web.archive.org/web/20190417094842/https://www.imdb.com/title/tt0273375/ |date=17 April 2019 }}&nbsp;– 1977 ten-episode TV series featuring ] as Tesla.
{{See also|Nikola Tesla in popular culture}}
* {{Webarchive|url=https://web.archive.org/web/20180805211353/https://www.imdb.com/title/tt0079985/ |date=5 August 2018 }}'&nbsp;– 1980 Documentary directed by ], featuring ] as Tesla and ] as ]
* &nbsp;– 1977 ten-episode TV series featuring ] as Tesla.
* '&nbsp;– 1980 Documentary directed by ], featuring ] as Tesla and ] as ] * {{Webarchive|url=https://web.archive.org/web/20170919070828/https://www.pbs.org/tesla/ |date=19 September 2017 }}&nbsp;– 2003 Documentary by Robert Uth, featuring ] as the voice of Tesla.
* &nbsp;– 2003 Documentary by Robert Uth, featuring ] as the voice of Tesla. * '']''&nbsp;– a 2016 documentary film by ] presented on the '']'' series.
* '']''&nbsp;– a 2020 biographical film by ] presented at the ].
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| DATE OF BIRTH = 10 July 1856
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| DATE OF DEATH = 7 January 1943
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Latest revision as of 11:41, 25 December 2024

Serbian-American engineer and inventor (1856–1943) For other uses, see Nikola Tesla (disambiguation).

Nikola Tesla
Никола Тесла
Head-and-shoulder photograph of a slender man with dark hair and moustache, dark suit and white-collar shirtTesla, c. 1890
Born(1856-07-10)10 July 1856
Smiljan, Austrian Empire
(now Croatia)
Died7 January 1943(1943-01-07) (aged 86)
New York City, U.S.
Resting placeNikola Tesla Museum, Belgrade, Serbia
CitizenshipAustria (1856–1891)
United States (1891–1943)
Alma materGraz University of Technology (dropped out)
Occupations
  • Engineer
  • futurist
  • inventor
Awards
Engineering career
Discipline
ProjectsWireless power transfer
Significant designInduction motor
Significant advancePolyphase electric power
Awards
Signature

Nikola Tesla (/ˈnɪkələˈtɛslə/; Serbian Cyrillic: Никола Тесла, [nǐkola têsla]; 10 July 1856 – 7 January 1943) was a Serbian-American engineer, futurist, and inventor. He is known for his contributions to the design of the modern alternating current (AC) electricity supply system.

Born and raised in the Austrian Empire, Tesla first studied engineering and physics in the 1870s without receiving a degree. He then gained practical experience in the early 1880s working in telephony and at Continental Edison in the new electric power industry. In 1884 he immigrated to the United States, where he became a naturalized citizen. He worked for a short time at the Edison Machine Works in New York City before he struck out on his own. With the help of partners to finance and market his ideas, Tesla set up laboratories and companies in New York to develop a range of electrical and mechanical devices. His AC induction motor and related polyphase AC patents, licensed by Westinghouse Electric in 1888, earned him a considerable amount of money and became the cornerstone of the polyphase system which that company eventually marketed.

Attempting to develop inventions he could patent and market, Tesla conducted a range of experiments with mechanical oscillators/generators, electrical discharge tubes, and early X-ray imaging. He also built a wirelessly controlled boat, one of the first ever exhibited. Tesla became well known as an inventor and demonstrated his achievements to celebrities and wealthy patrons at his lab, and was noted for his showmanship at public lectures. Throughout the 1890s, Tesla pursued his ideas for wireless lighting and worldwide wireless electric power distribution in his high-voltage, high-frequency power experiments in New York and Colorado Springs. In 1893, he made pronouncements on the possibility of wireless communication with his devices. Tesla tried to put these ideas to practical use in his unfinished Wardenclyffe Tower project, an intercontinental wireless communication and power transmitter, but ran out of funding before he could complete it.

After Wardenclyffe, Tesla experimented with a series of inventions in the 1910s and 1920s with varying degrees of success. Having spent most of his money, Tesla lived in a series of New York hotels, leaving behind unpaid bills. He died in New York City in January 1943. Tesla's work fell into relative obscurity following his death, until 1960, when the General Conference on Weights and Measures named the International System of Units (SI) measurement of magnetic flux density the tesla in his honor. There has been a resurgence in popular interest in Tesla since the 1990s.

Early years

Tesla's rebuilt birth house (parish hall) and the church where his father served in Smiljan, Croatia. The site was made into a museum about him.

Nikola Tesla was born into an ethnic Serb family in the village of Smiljan, within the Military Frontier, in the Austrian Empire (present-day Croatia), on 10 July 1856. His father, Milutin Tesla (1819–1879), was a priest of the Eastern Orthodox Church. His father's brother Josif was a lecturer at a military academy who wrote several textbooks on mathematics.

Tesla's mother, Georgina "Đuka" Mandić (1822–1892), whose father was also an Eastern Orthodox Church priest, had a talent for making home craft tools and mechanical appliances and the ability to memorize Serbian epic poems. Đuka had never received a formal education. Tesla credited his eidetic memory and creative abilities to his mother's genetics and influence.

Tesla was the fourth of five children. He had three sisters, Milka, Angelina, and Marica, and an older brother named Dane, who was killed in a horse-riding accident when Tesla was aged six or seven. In 1861, Tesla attended primary school in Smiljan where he studied German, arithmetic, and religion. In 1862, the Tesla family moved to the nearby town of Gospić, where Tesla's father worked as parish priest. Nikola completed primary school, followed by middle school. In 1870, Tesla moved to Karlovac to attend high school at the Higher Real Gymnasium where the classes were held in German, as it was usual throughout schools within the Austro-Hungarian Military Frontier. Later in his patent applications, before he obtained American citizenship, Tesla would identify himself as 'of Smiljan, Lika, border country of Austria-Hungary'.

Tesla's father, Milutin, was an Orthodox priest in the village of Smiljan.

Tesla later wrote that he became interested in demonstrations of electricity by his physics professor. Tesla noted that these demonstrations of this "mysterious phenomena" made him want "to know more of this wonderful force". Tesla was able to perform integral calculus in his head, which prompted his teachers to believe that he was cheating. He finished a four-year term in three years, graduating in 1873.

After graduating Tesla returned to Smiljan but soon contracted cholera, was bedridden for nine months and was near death multiple times. In a moment of despair, Tesla's father (who had originally wanted him to enter the priesthood), promised to send him to the best engineering school if he recovered from the illness. Tesla later said that he had read Mark Twain's earlier works while recovering from his illness.

The next year Tesla evaded conscription into the Austro-Hungarian Army in Smiljan by running away southeast of Lika to Tomingaj, near Gračac. There he explored the mountains wearing hunter's garb. Tesla said that this contact with nature made him stronger, both physically and mentally. He enrolled at the Imperial-Royal Technical College in Graz in 1875 on a Military Frontier scholarship. Tesla passed nine exams (nearly twice as many as required) and received a letter of commendation from the dean of the technical faculty to his father, which stated, "Your son is a star of first rank." At Graz, Tesla noted his fascination with the detailed lectures on electricity presented by Professor Jakob Pöschl and described how he made suggestions on improving the design of an electric motor the professor was demonstrating. But by his third year he was failing in school and never graduated, leaving Graz in December 1878. One biographer suggests Tesla was not studying and may have been expelled for gambling and womanizing.

Tesla aged 23, c. 1879

Tesla's family did not hear from him after he left school. There was a rumor among his classmates that he had drowned in the nearby river Mur but in January one of them ran into Tesla in the town of Maribor and reported that encounter to Tesla's family. It turned out Tesla had been working there as a draftsman for 60 florins per month. In March 1879, Milutin finally located his son and tried to convince him to return home and take up his education in Prague. Tesla returned to Gospić later that month when he was deported for not having a residence permit. Tesla's father died the next month, on 17 April 1879, at the age of 60 after an unspecified illness. During the rest of the year Tesla taught a large class of students in his old school in Gospić.

In January 1880, two of Tesla's uncles put together enough money to help him leave Gospić for Prague, where he was to study. He arrived too late to enroll at Charles-Ferdinand University; he had never studied Greek, a required subject; and he was illiterate in Czech, another required subject. Tesla did, however, attend lectures in philosophy at the university as an auditor but he did not receive grades for the courses.

Working at Budapest Telephone Exchange

Tesla moved to Budapest, Hungary, in 1881 to work under Tivadar Puskás at a telegraph company, the Budapest Telephone Exchange. Upon arrival, Tesla realized that the company, then under construction, was not functional, so he worked as a draftsman in the Central Telegraph Office instead. Within a few months, the Budapest Telephone Exchange became functional, and Tesla was allocated the chief electrician position. During his employment, Tesla made many improvements to the Central Station equipment and claimed to have perfected a telephone repeater or amplifier, which was never patented nor publicly described.

Working at Edison

In 1882, Tivadar Puskás got Tesla another job in Paris with the Continental Edison Company. Tesla began working in what was then a brand new industry, installing indoor incandescent lighting citywide in large scale electric power utility. The company had several subdivisions and Tesla worked at the Société Electrique Edison, the division in the Ivry-sur-Seine suburb of Paris in charge of installing the lighting system. There he gained a great deal of practical experience in electrical engineering. Management took notice of his advanced knowledge in engineering and physics and soon had him designing and building improved versions of generating dynamos and motors. They also sent him on to troubleshoot engineering problems at other Edison utilities being built around France and in Germany.

Moving to the United States

Edison Machine Works on Goerck Street, New York. Tesla found the change from cosmopolitan Europe to working at this shop, located among the tenements on Manhattan's lower east side, a "painful surprise".

In 1884, Edison manager Charles Batchelor, who had been overseeing the Paris installation, was brought back to the United States to manage the Edison Machine Works, a manufacturing division situated in New York City, and asked that Tesla be brought to the United States as well. In June 1884, Tesla emigrated and began working almost immediately at the Machine Works on Manhattan's Lower East Side, an overcrowded shop with a workforce of several hundred machinists, laborers, managing staff, and 20 "field engineers" struggling with the task of building the large electric utility in that city. As in Paris, Tesla was working on troubleshooting installations and improving generators. Historian W. Bernard Carlson notes Tesla may have met company founder Thomas Edison only a couple of times. One of those times was noted in Tesla's autobiography where, after staying up all night repairing the damaged dynamos on the ocean liner SS Oregon, he ran into Batchelor and Edison, who made a quip about their "Parisian" being out all night. After Tesla told them he had been up all night fixing the Oregon, Edison commented to Batchelor that "this is a damned good man". One of the projects given to Tesla was to develop an arc lamp-based street lighting system. Arc lighting was the most popular type of street lighting but it required high voltages and was incompatible with the Edison low-voltage incandescent system, causing the company to lose contracts in some cities. Tesla's designs were never put into production, possibly because of technical improvements in incandescent street lighting or because of an installation deal that Edison made with an arc lighting company.

Tesla had been working at the Machine Works for a total of six months when he quit. What event precipitated his leaving is unclear. It may have been over a bonus he did not receive, either for redesigning generators or for the arc lighting system that was shelved. Tesla had previous run-ins with the Edison company over unpaid bonuses he believed he had earned. In his autobiography, Tesla stated the manager of the Edison Machine Works offered a $50,000 bonus to design "twenty-four different types of standard machines" "but it turned out to be a practical joke". Later versions of this story have Thomas Edison himself offering and then reneging on the deal, quipping "Tesla, you don't understand our American humor". The size of the bonus in either story has been noted as odd since Machine Works manager Batchelor was stingy with pay and the company did not have that amount of cash (equal to $1,695,556 today) on hand. Tesla's diary contains just one comment on what happened at the end of his employment, a note he scrawled across the two pages covering 7 December 1884, to 4 January 1885, saying "Good By to the Edison Machine Works".

Tesla Electric Light and Manufacturing

Soon after leaving the Edison company, Tesla was working on patenting an arc lighting system, possibly the same one he had developed at Edison. In March 1885, he met with patent attorney Lemuel W. Serrell, the same attorney used by Edison, to obtain help with submitting the patents. Serrell introduced Tesla to two businessmen, Robert Lane and Benjamin Vail, who agreed to finance an arc lighting manufacturing and utility company in Tesla's name, the Tesla Electric Light and Manufacturing Company. Tesla worked for the rest of the year obtaining the patents that included an improved DC generator, the first patents issued to Tesla in the US, and building and installing the system in Rahway, New Jersey. Tesla's new system gained notice in the technical press, which commented on its advanced features.

The investors showed little interest in Tesla's ideas for new types of alternating current motors and electrical transmission equipment. After the utility was up and running in 1886, they decided that the manufacturing side of the business was too competitive and opted to simply run an electric utility. They formed a new utility company, abandoning Tesla's company and leaving the inventor penniless. Tesla even lost control of the patents he had generated, since he had assigned them to the company in exchange for stock. He had to work at various electrical repair jobs and as a ditch digger for $2 per day. Later in life Tesla recounted that part of 1886 as a time of hardship, writing "My high education in various branches of science, mechanics and literature seemed to me like a mockery".

AC and the induction motor

Drawing from U.S. patent 381,968, illustrating the principle of Tesla's alternating current induction motor

In late 1886, Tesla met Alfred S. Brown, a Western Union superintendent, and New York attorney Charles Fletcher Peck. The two men were experienced in setting up companies and promoting inventions and patents for financial gain. Based on Tesla's new ideas for electrical equipment, including a thermo-magnetic motor idea, they agreed to back the inventor financially and handle his patents. Together they formed the Tesla Electric Company in April 1887, with an agreement that profits from generated patents would go 1⁄3 to Tesla, 1⁄3 to Peck and Brown, and 1⁄3 to fund development. They set up a laboratory for Tesla at 89 Liberty Street in Manhattan, where he worked on improving and developing new types of electric motors, generators, and other devices.

In 1887, Tesla developed an induction motor that ran on alternating current (AC), a power system format that was rapidly expanding in Europe and the United States because of its advantages in long-distance, high-voltage transmission. The motor used polyphase current, which generated a rotating magnetic field to turn the motor (a principle that Tesla claimed to have conceived in 1882). This innovative electric motor, patented in May 1888, was a simple self-starting design that did not need a commutator, thus avoiding sparking and the high maintenance of constantly servicing and replacing mechanical brushes.

Along with getting the motor patented, Peck and Brown arranged to get the motor publicized, starting with independent testing to verify it was a functional improvement, followed by press releases sent to technical publications for articles to run concurrently with the issue of the patent. Physicist William Arnold Anthony (who tested the motor) and Electrical World magazine editor Thomas Commerford Martin arranged for Tesla to demonstrate his AC motor on 16 May 1888 at the American Institute of Electrical Engineers. Engineers working for the Westinghouse Electric & Manufacturing Company reported to George Westinghouse that Tesla had a viable AC motor and related power system—something Westinghouse needed for the alternating current system he was already marketing. Westinghouse looked into getting a patent on a similar commutator-less, rotating magnetic field-based induction motor developed in 1885 and presented in a paper in March 1888 by Italian physicist Galileo Ferraris, but decided that Tesla's patent would probably control the market.

Tesla's AC dynamo-electric machine (AC electric generator) in an 1888 U.S. patent 390,721

In July 1888, Brown and Peck negotiated a licensing deal with George Westinghouse for Tesla's polyphase induction motor and transformer designs for $60,000 in cash and stock and a royalty of $2.50 per AC horsepower produced by each motor. Westinghouse also hired Tesla for one year for the large fee of $2,000 ($67,800 in today's dollars) per month to be a consultant at the Westinghouse Electric & Manufacturing Company's Pittsburgh labs.

During that year, Tesla worked in Pittsburgh, helping to create an alternating current system to power the city's streetcars. He found it a frustrating period because of conflicts with the other Westinghouse engineers over how best to implement AC power. Between them, they settled on a 60-cycle AC system that Tesla proposed (to match the working frequency of Tesla's motor), but they soon found that it would not work for streetcars, since Tesla's induction motor could run only at a constant speed. They ended up using a DC traction motor instead.

Market turmoil

Tesla's demonstration of his induction motor and Westinghouse's subsequent licensing of the patent, both in 1888, came at the time of extreme competition between electric companies. The three big firms, Westinghouse, Edison, and Thomson-Houston Electric Company, were trying to grow in a capital-intensive business while financially undercutting each other. There was even a "war of currents" propaganda campaign going on, with Edison Electric claiming their direct current system was better and safer than the Westinghouse alternating current system and Thomson-Houston sometimes siding with Edison. Competing in this market meant Westinghouse would not have the cash or engineering resources to develop Tesla's motor and the related polyphase system right away.

Two years after signing the Tesla contract, Westinghouse Electric was in trouble. The near collapse of Barings Bank in London triggered the financial panic of 1890, causing investors to call in their loans to Westinghouse Electric. The sudden cash shortage forced the company to refinance its debts. The new lenders demanded that Westinghouse cut back on what looked like excessive spending on acquisition of other companies, research, and patents, including the per motor royalty in the Tesla contract. At that point, the Tesla induction motor had been unsuccessful and was stuck in development. Westinghouse was paying a $15,000-a-year guaranteed royalty even though operating examples of the motor were rare and polyphase power systems needed to run it were even rarer. In early 1891, George Westinghouse explained his financial difficulties to Tesla in stark terms, saying that, if he did not meet the demands of his lenders, he would no longer be in control of Westinghouse Electric and Tesla would have to "deal with the bankers" to try to collect future royalties. The advantages of having Westinghouse continue to champion the motor probably seemed obvious to Tesla and he agreed to release the company from the royalty payment clause in the contract. Six years later Westinghouse purchased Tesla's patent for a lump sum payment of $216,000 as part of a patent-sharing agreement signed with General Electric (a company created from the 1892 merger of Edison and Thomson-Houston).

New York laboratories

Mark Twain in Tesla's lab, 1894
Mark Twain in Tesla's South Fifth Avenue laboratory, 1894

The money Tesla made from licensing his AC patents made him independently wealthy and gave him the time and funds to pursue his own interests. In 1889, Tesla moved out of the Liberty Street shop Peck and Brown had rented and for the next dozen years worked out of a series of workshop/laboratory spaces in Manhattan. These included a lab at 175 Grand Street (1889–1892), the fourth floor of 33–35 South Fifth Avenue (1892–1895), and sixth and seventh floors of 46 & 48 East Houston Street (1895–1902). Tesla and his hired staff conducted some of his most significant work in these workshops.

Tesla coil

Main article: Tesla coil

In the summer of 1889, Tesla traveled to the 1889 Exposition Universelle in Paris and learned of Heinrich Hertz's 1886–1888 experiments that proved the existence of electromagnetic radiation, including radio waves. In repeating and then expanding on these experiments Tesla tried powering a Ruhmkorff coil with a high speed alternator he had been developing as part of an improved arc lighting system but found that the high-frequency current overheated the iron core and melted the insulation between the primary and secondary windings in the coil. To fix this problem Tesla came up with his "oscillating transformer", with an air gap instead of insulating material between the primary and secondary windings and an iron core that could be moved to different positions in or out of the coil. Later called the Tesla coil, it would be used to produce high-voltage, low-current, high frequency alternating-current electricity. He would use this resonant transformer circuit in his later wireless power work.

Citizenship

On 30 July 1891, aged 35, Tesla became a naturalized citizen of the United States. In the same year, he patented his Tesla coil.

Wireless lighting

Tesla demonstrating wireless lighting by "electrostatic induction" during an 1891 lecture at Columbia College via two long Geissler tubes (similar to neon tubes) in his hands

After 1890, Tesla experimented with transmitting power by inductive and capacitive coupling using high AC voltages generated with his Tesla coil. He attempted to develop a wireless lighting system based on near-field inductive and capacitive coupling and conducted a series of public demonstrations where he lit Geissler tubes and even incandescent light bulbs from across a stage. He spent most of the decade working on variations of this new form of lighting with the help of various investors but none of the ventures succeeded in making a commercial product out of his findings.

In 1893 at St. Louis, Missouri, the Franklin Institute in Philadelphia, Pennsylvania and the National Electric Light Association, Tesla told onlookers that he was sure a system like his could eventually conduct "intelligible signals or perhaps even power to any distance without the use of wires" by conducting it through the Earth.

Tesla served as a vice-president of the American Institute of Electrical Engineers from 1892 to 1894, the forerunner of the modern-day IEEE (along with the Institute of Radio Engineers).

Polyphase system and the Columbian Exposition

A Westinghouse display of the "Tesla Polyphase System" at Chicago's 1893 Columbian Exposition

By the beginning of 1893, Westinghouse engineer Charles F. Scott and then Benjamin G. Lamme had made progress on an efficient version of Tesla's induction motor. Lamme found a way to make the polyphase system it would need compatible with older single-phase AC and DC systems by developing a rotary converter. Westinghouse Electric now had a way to provide electricity to all potential customers and started branding their polyphase AC system as the "Tesla Polyphase System". They believed that Tesla's patents gave them patent priority over other polyphase AC systems.

Westinghouse Electric asked Tesla to participate in the 1893 World's Columbian Exposition in Chicago where the company had a large space in the "Electricity Building" devoted to electrical exhibits. Westinghouse Electric won the bid to light the Exposition with alternating current and it was a key event in the history of AC power, as the company demonstrated to the American public the safety, reliability, and efficiency of an alternating current system that was polyphase and could also supply the other AC and DC exhibits at the fair.

A special exhibit space was set up to display various forms and models of Tesla's induction motor. The rotating magnetic field that drove them was explained through a series of demonstrations including an Egg of Columbus that used the two-phase coil found in an induction motor to spin a copper egg making it stand on end.

Tesla visited the fair for a week during its six-month run to attend the International Electrical Congress and put on a series of demonstrations at the Westinghouse exhibit. A specially darkened room had been set up where Tesla showed his wireless lighting system, using a demonstration he had previously performed throughout America and Europe; these included using high-voltage, high-frequency alternating current to light wireless gas-discharge lamps.

An observer noted:

Within the room were 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".

Steam-powered oscillating generator

Main article: Tesla's oscillator

During his presentation at the International Electrical Congress in the Columbian Exposition Agriculture Hall, Tesla introduced his steam powered reciprocating electricity generator that he patented that year, something he thought was a better way to generate alternating current. Steam was forced into the oscillator and rushed out through a series of ports, pushing a piston up and down that was attached to an armature. The magnetic armature vibrated up and down at high speed, producing an alternating magnetic field. This induced alternating electric current in the wire coils located adjacent. It did away with the complicated parts of a steam engine/generator, but never caught on as a feasible engineering solution to generate electricity.

Consulting on Niagara

In 1893, Edward Dean Adams, who headed the Niagara Falls Cataract Construction Company, sought Tesla's opinion on what system would be best to transmit power generated at the falls. Over several years, there had been a series of proposals and open competitions on how best to do it. Among the systems proposed by several US and European companies were two-phase and three-phase AC, high-voltage DC, and compressed air. Adams asked Tesla for information about the current state of all the competing systems. Tesla advised Adams that a two-phased system would be the most reliable and that there was a Westinghouse system to light incandescent bulbs using two-phase alternating current. The company awarded a contract to Westinghouse Electric for building a two-phase AC generating system at the Niagara Falls, based on Tesla's advice and Westinghouse's demonstration at the Columbian Exposition. At the same time, a further contract was awarded to General Electric to build the AC distribution system.

The Nikola Tesla Company

In 1895, Edward Dean Adams, impressed with what he saw when he toured Tesla's lab, agreed to help found the Nikola Tesla Company, set up to fund, develop, and market a variety of previous Tesla patents and inventions as well as new ones. Alfred Brown signed on, bringing along patents developed under Peck and Brown. The board was filled out with William Birch Rankine and Charles F. Coaney. It found few investors since the mid-1890s were a tough time financially, and the wireless lighting and oscillators patents it was set up to market never panned out. The company handled Tesla's patents for decades to come.

Lab fire

In the early morning hours of 13 March 1895, the South Fifth Avenue building that housed Tesla's lab caught fire. It started in the basement of the building and was so intense Tesla's 4th-floor lab burned and collapsed into the second floor. The fire not only set back Tesla's ongoing projects, but it also destroyed a collection of early notes and research material, models, and demonstration pieces, including many that had been exhibited at the 1893 Worlds Colombian Exposition. Tesla told The New York Times "I am in too much grief to talk. What can I say?". After the fire Tesla moved to 46 & 48 East Houston Street and rebuilt his lab on the 6th and 7th floors.

X-ray experimentation

X-ray Tesla took of his hand

Starting in 1894, Tesla began investigating what he referred to as radiant energy of "invisible" kinds after he had noticed damaged film in his laboratory in previous experiments (later identified as "Roentgen rays" or "X-rays"). His early experiments were with Crookes tubes, a cold cathode electrical discharge tube. Tesla may have inadvertently captured an X-ray image—predating, by a few weeks, Wilhelm Röntgen's December 1895 announcement of the discovery of X-rays—when he tried to photograph Mark Twain illuminated by a Geissler tube, an earlier type of gas discharge tube. The only thing captured in the image was the metal locking screw on the camera lens.

In March 1896, after hearing of Röntgen's discovery of X-ray and X-ray imaging (radiography), Tesla proceeded to do his own experiments in X-ray imaging, developing a high-energy single-terminal vacuum tube of his own design that had no target electrode and that worked from the output of the Tesla coil (the modern term for the phenomenon produced by this device is bremsstrahlung or braking radiation). In his 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".

Tesla noted the hazards of working with his circuit and single-node X-ray-producing devices. In his many notes on 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 by the ozone generated in contact with the skin, and to a lesser extent, by nitrous acid. Tesla incorrectly believed that X-rays were longitudinal waves, such as those produced in waves in plasmas. These plasma waves can occur in force-free magnetic fields.

On 11 July 1934, the New York Herald Tribune published an article on Tesla, in which he recalled an event that occasionally took place while experimenting with his single-electrode vacuum tubes. A minute particle would break off the cathode, pass out of the tube, and physically strike him:

Tesla said he could feel a sharp stinging pain where it entered his body, and again at the place where it passed out. In comparing these particles with the bits of metal projected by his "electric gun", Tesla said, "The particles in the beam of force ... will travel much faster than such particles ... and they will travel in concentrations".

Radio remote control

In 1898, Tesla demonstrated a radio-controlled boat, which he hoped to sell as a guided torpedo to navies around the world.

In 1898, Tesla demonstrated a boat that used a coherer-based radio control—which he dubbed "telautomaton"—to the public during an electrical exhibition at Madison Square Garden. Tesla tried to sell his idea to the US military as a type of radio-controlled torpedo, but they showed little interest. Remote radio control remained a novelty until World War I and afterward, when a number of countries used it in military programs. Tesla took the opportunity to further demonstrate "Teleautomatics" in an address to a meeting of the Commercial Club in Chicago, while he was traveling to Colorado Springs, on 13 May 1899.

Wireless power

Further information: Wireless power transfer § Tesla
Tesla sitting in front of a spiral coil used in his wireless power experiments at his East Houston St. laboratory

From the 1890s through 1906, Tesla spent a great deal of his time and fortune on a series of projects trying to develop the transmission of electrical power without wires. It was an expansion of his idea of using coils to transmit power that he had been demonstrating in wireless lighting. He saw this as not only a way to transmit large amounts of power around the world but also, as he had pointed out in his earlier lectures, a way to transmit worldwide communications.

At the time Tesla was formulating his ideas, there was no feasible way to wirelessly transmit communication signals over long distances, let alone large amounts of power. Tesla had studied radio waves early on, and came to the conclusion that part of the existing study on them, by Hertz, was incorrect. Also, this new form of radiation was widely considered at the time to be a short-distance phenomenon that seemed to die out in less than a mile. Tesla noted that, even if theories on radio waves were true, they were totally worthless for his intended purposes since this form of "invisible light" would diminish over a distance just like any other radiation and would travel in straight lines right out into space, becoming "hopelessly lost".

By the mid-1890s, Tesla was working on the idea that he might be able to conduct electricity long distance through the Earth or the atmosphere, and began working on experiments to test this idea including setting up a large resonance transformer magnifying transmitter in his East Houston Street lab. Seeming to borrow from a common idea at the time that the Earth's atmosphere was conductive, he proposed a system composed of balloons suspending, transmitting, and receiving, electrodes in the air above 30,000 feet (9,100 m) in altitude, where he thought the lower pressure would allow him to send high voltages (millions of volts) long distances.

Colorado Springs

See also: Tesla Experimental Station; Magnifying transmitter; and Colorado Springs Notes, 1899–1900
Tesla's Colorado Springs laboratory

To further study the conductive nature of low-pressure air, Tesla set up an experimental station at high altitude in Colorado Springs during 1899. There he could safely operate much larger coils than in the cramped confines of his New York lab, and an associate had made an arrangement for the El Paso Electric Light Company to supply alternating current free of charge. To fund his experiments, he convinced John Jacob Astor IV to invest $100,000 ($3,662,400 in today's dollars) to become a majority shareholder in the Nikola Tesla Company. Astor thought he was primarily investing in the new wireless lighting system. Instead, Tesla used the money to fund his Colorado Springs experiments. Upon his arrival, he told reporters that he planned to conduct wireless telegraphy experiments, transmitting signals from Pikes Peak to Paris.

A multiple exposure picture of Tesla sitting next to his "magnifying transmitter" generating millions of volts. The 7-metre (23 ft) long arcs were not part of the normal operation, but only produced for effect by rapidly cycling the power switch.

There, he conducted experiments with a large coil operating in the megavolts range, producing artificial lightning (and thunder) consisting of millions of volts and discharges of up to 135 feet (41 m) in length, and, at one point, inadvertently burned out the generator in El Paso, causing a power outage. The observations he made of the electronic noise of lightning strikes led him to (incorrectly) conclude that he could use the entire globe of the Earth to conduct electrical energy.

During his time at his laboratory, Tesla observed unusual signals from his receiver which he speculated to be communications from another planet. He mentioned them in a letter to a reporter in December 1899 and to the Red Cross Society in December 1900. Reporters treated it as a sensational story and jumped to the conclusion Tesla was hearing signals from Mars. He expanded on the signals he heard in a 9 February 1901 Collier's Weekly article entitled "Talking With Planets", where he said it had not been immediately apparent to him that he was hearing "intelligently controlled signals" and that the signals could have come from Mars, Venus, or other planets. It has been hypothesized that he may have intercepted Guglielmo Marconi's European experiments in July 1899—Marconi may have transmitted the letter S (dot/dot/dot) in a naval demonstration, the same three impulses that Tesla hinted at hearing in Colorado—or signals from another experimenter in wireless transmission.

Tesla had an agreement with the editor of The Century Magazine to produce an article on his findings. The magazine sent a photographer to Colorado to photograph the work being done there. The article, titled "The Problem of Increasing Human Energy", appeared in the June 1900 edition of the magazine. He explained the superiority of the wireless system he envisioned but the article was more of a lengthy philosophical treatise than an understandable scientific description of his work, illustrated with what were to become iconic images of Tesla and his Colorado Springs experiments.

Wardenclyffe

Main article: Wardenclyffe Tower
Tesla's Wardenclyffe plant on Long Island in 1904. From this facility, Tesla hoped to demonstrate wireless transmission of electrical energy across the Atlantic.

Tesla made the rounds in New York trying to find investors for what he thought would be a viable system of wireless transmission, wining and dining them at the Waldorf-Astoria's Palm Garden (the hotel where he was living at the time), The Players Club, and Delmonico's. In March 1901, he obtained $150,000 ($5,493,600 in today's dollars) from J. P. Morgan in return for a 51% share of any generated wireless patents, and began planning the Wardenclyffe Tower facility to be built in Shoreham, New York, 100 miles (161 km) east of the city on the North Shore of Long Island.

By July 1901, Tesla had expanded his plans to build a more powerful transmitter to leap ahead of Marconi's radio-based system, which Tesla thought was a copy of his own. He approached Morgan to ask for more money to build the larger system, but Morgan refused to supply any further funds. In December 1901, Marconi successfully transmitted the letter S from England to Newfoundland, defeating Tesla in the race to be first to complete such a transmission. A month after Marconi's success, Tesla tried to get Morgan to back an even larger plan to transmit messages and power by controlling "vibrations throughout the globe". Over the next five years, Tesla wrote more than 50 letters to Morgan, pleading for and demanding additional funding to complete the construction of Wardenclyffe. Tesla continued the project for another nine months into 1902. The tower was erected to its full height of 187 feet (57 m). In June 1902, Tesla moved his lab operations from Houston Street to Wardenclyffe.

Investors on Wall Street were putting their money into Marconi's system, and some in the press began turning against Tesla's project, claiming it was a hoax. The project came to a halt in 1905, and in 1906, the financial problems and other events may have led to what Tesla biographer Marc J. Seifer suspects was a nervous breakdown on Tesla's part. Tesla mortgaged the Wardenclyffe property to cover his debts at the Waldorf-Astoria, which eventually amounted to $20,000 ($608,400 in today's dollars). He lost the property in foreclosure in 1915, and in 1917 the Tower was demolished by the new owner to make the land a more viable real estate asset.

Later years

After Wardenclyffe closed, Tesla continued to write to Morgan; after "the great man" died, Tesla wrote to Morgan's son Jack, trying to get further funding for the project. In 1906, Tesla opened offices at 165 Broadway in Manhattan, trying to raise further funds by developing and marketing his patents. He went on to have offices at the Metropolitan Life Tower from 1910 to 1914; rented for a few months at the Woolworth Building, moving out because he could not afford the rent; and then to office space at 8 West 40th Street from 1915 to 1925. After moving to 8 West 40th Street, he was effectively bankrupt. Most of his patents had run out and he was having trouble with the new inventions he was trying to develop.

Bladeless turbine

Main article: Tesla turbine
Tesla's bladeless turbine design

On his 50th birthday, in 1906, Tesla demonstrated a 200 horsepower (150 kilowatts) 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 100–5,000 hp. Tesla worked with several companies including from 1919 to 1922 in Milwaukee, for Allis-Chalmers. He spent most of his time trying to perfect the Tesla turbine with Hans Dahlstrand, the head engineer at the company, but engineering difficulties meant it was never made into a practical device. Tesla did license the idea to a precision instrument company and it found use in the form of luxury car speedometers and other instruments.

Wireless lawsuits

When World War I broke out, the British cut the transatlantic telegraph cable linking the US to Germany in order to control the flow of information between the two countries. They also tried to shut off German wireless communication to and from the US by having the US Marconi Company sue the German radio company Telefunken for patent infringement. Telefunken brought in the physicists Jonathan Zenneck and Karl Ferdinand Braun for their defense, and hired Tesla as a witness for two years for $1,000 a month. The case stalled and then went moot when the US entered the war against Germany in 1917.

In 1915, Tesla attempted to sue the Marconi Company for infringement of his wireless tuning patents. Marconi's initial radio patent had been awarded in the US in 1897, but his 1900 patent submission covering improvements to radio transmission had been rejected several times, before it was finally approved in 1904, on the grounds that it infringed on other existing patents including two 1897 Tesla wireless power tuning patents. Tesla's 1915 case went nowhere, but in a related case, where the Marconi Company tried to sue the US government over WWI patent infringements, a Supreme Court of the United States 1943 decision restored the prior patents of Oliver Lodge, John Stone, and Tesla. The court declared that their decision had no bearing on Marconi's claim as the first to achieve radio transmission, just that since Marconi's claim to certain patented improvements were questionable, the company could not claim infringement on those same patents.

Nobel Prize rumors

On 6 November 1915, a Reuters news agency report from London had the 1915 Nobel Prize in Physics awarded to Thomas Edison and Nikola Tesla; however, on 15 November, a Reuters story from Stockholm stated the prize that year was being awarded to William Henry Bragg and Lawrence Bragg "for their services in the analysis of crystal structure by means of X-rays". There were unsubstantiated rumors at the time that either Tesla or Edison had refused the prize. The Nobel Foundation said, "Any rumor that a person has not been given a Nobel Prize because he has made known his intention to refuse the reward is ridiculous"; a recipient could decline a Nobel Prize only after he is announced a winner.

There have been subsequent claims by Tesla biographers that Edison and Tesla were the original recipients and that neither was given the award because of their animosity toward each other; 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; that both rejected any possibility of sharing it; and even that a wealthy Edison refused it to keep Tesla from getting the $20,000 prize money.

In the years after these rumors, neither Tesla nor Edison won a Nobel prize (although Edison received one of 38 possible bids in 1915 and Tesla received one of 38 possible bids in 1937).

Other awards, patents and ideas

Tesla won numerous medals and awards over this time. They include:

Second banquet meeting of the Institute of Radio Engineers, 23 April 1915. Tesla is seen standing in the center.

Tesla attempted to market several devices based on the production of ozone. These included his 1900 Tesla Ozone Company selling an 1896 patented device based on his Tesla coil, used to bubble ozone through different types of oils to make a therapeutic gel. He also tried to develop a variation of this a few years later as a room sanitizer for hospitals.

Tesla theorized that the application of electricity to the brain enhanced intelligence. In 1912, he crafted "a plan to make dull students bright by saturating them unconsciously with electricity," wiring the walls of a schoolroom and, "saturating with infinitesimal electric waves vibrating at high frequency. The whole room will thus, Mr. Tesla claims, be converted into a health-giving and stimulating electromagnetic field or 'bath.'" The plan was, at least provisionally, approved by then superintendent of New York City schools, William H. Maxwell.

Before World War I, Tesla sought overseas investors. After the war started, Tesla lost the funding he was receiving from his patents in European countries.

In the August 1917 edition of the magazine Electrical Experimenter, Tesla postulated that electricity could be used to locate submarines via using the reflection of an "electric ray" of "tremendous frequency," with the signal being viewed on a fluorescent screen (a system that has been noted to have a superficial resemblance to modern radar). Tesla was incorrect in his assumption that high-frequency radio waves would penetrate water. Émile Girardeau, who helped develop France's first radar system in the 1930s, noted in 1953 that Tesla's general speculation that a very strong high-frequency signal would be needed was correct. Girardeau said, "(Tesla) was prophesying or dreaming, since he had at his disposal no means of carrying them out, but one must add that if he was dreaming, at least he was dreaming correctly".

In 1928, Tesla received patent, U.S. patent 1,655,114, for a biplane design capable of vertical take-off and landing (VTOL), which "gradually tilted through manipulation of the elevator devices" in flight until it was flying like a conventional plane. This impractical design was something Tesla thought would sell for less than $1,000.

Tesla had a further office at 350 Madison Ave but by 1928 he no longer had a laboratory or funding.

Living circumstances

Tesla lived at the Waldorf Astoria in New York City from 1900 and ran up a large bill. He moved to the St. Regis Hotel in 1922 and followed a pattern from then on of moving to a different hotel every few years and leaving unpaid bills behind.

Tesla walked to the park every day to feed the pigeons. He began feeding them at the window of his hotel room and nursed injured birds back to health. He said that he had been visited by a certain injured white pigeon daily. He spent over $2,000 (equivalent to $36,410 in 2023) to care for the bird, including a device he built to support her comfortably while her broken wing and leg healed. Tesla stated:

I have been feeding pigeons, thousands of them for years. But there was one, a beautiful bird, pure white with light grey tips on its wings; that one was different. It was a female. I had only to wish and call her and she would come flying to me. I loved that pigeon as a man loves a woman, and she loved me. As long as I had her, there was a purpose to my life.

Tesla's unpaid bills, as well as complaints about the mess made by pigeons, led to his eviction from St. Regis in 1923. He was also forced to leave the Hotel Pennsylvania in 1930 and the Hotel Governor Clinton in 1934. At one point he also took rooms at the Hotel Marguery.

Tesla moved to the Hotel New Yorker in 1934. At this time Westinghouse Electric & Manufacturing Company began paying him $125 (equivalent to $2,850 in 2023) per month in addition to paying his rent. Accounts of how this came about vary. Several sources claim that Westinghouse was concerned, or possibly warned, about potential bad publicity arising from the impoverished conditions in which their former star inventor was living. The payment has been described as being couched as a "consulting fee" to get around Tesla's aversion to accepting charity. Tesla biographer Marc Seifer described the Westinghouse payments as a type of "unspecified settlement".

Birthday press conferences

Tesla on Time magazine commemorating his 75th birthday

In 1931, a young journalist whom Tesla befriended, Kenneth M. Swezey, organized a celebration for the inventor's 75th birthday. Tesla received congratulations from figures in science and engineering such as Albert Einstein, and he was also featured on the cover of Time magazine. The cover caption "All the world's his power house" noted his contribution to electrical power generation. The party went so well that Tesla made it an annual event, an occasion where he would put out a large spread of food and drink—featuring dishes of his own creation. He invited the press in order to see his inventions and hear stories about his past exploits, views on current events, and sometimes baffling claims.

Newspaper representation of the thought camera Tesla described at his 1933 birthday party

At the 1932 party, Tesla claimed he had invented a motor that would run on cosmic rays. In 1933, at age 77, Tesla told reporters at the event that, after 35 years of work, he was on the verge of producing proof of a new form of energy. He claimed it was a theory of energy that was "violently opposed" to Einsteinian physics and could be tapped with an apparatus that would be cheap to run and last 500 years. He also told reporters he was working on a way to transmit individualized private radio wavelengths, working on breakthroughs in metallurgy, and developing a way to photograph the retina to record thought.

At the 1934 occasion, Tesla told reporters he had designed a superweapon he claimed would end all war. He called it "teleforce", but was usually referred to as his death ray. In 1940, the New York Times gave a range for the ray of 250 miles (400 km), with an expected development cost of US$2 million (equivalent to $43.5 million in 2023). Tesla described it as a defensive weapon that would be put up along the border of a country and be used against attacking ground-based infantry or aircraft. Tesla never revealed detailed plans of how the weapon worked during his lifetime but, in 1984, they surfaced at the Nikola Tesla Museum archive in Belgrade. The treatise, The New Art of Projecting Concentrated Non-dispersive Energy through the Natural Media, described an open-ended vacuum tube with a gas jet seal that allows particles to exit, a method of charging slugs of tungsten or mercury to millions of volts, and directing them in streams (through electrostatic repulsion). Tesla tried to attract interest of the US War Department, United Kingdom, Soviet Union, and Yugoslavia in the device.

In 1935, at his 79th birthday party, Tesla covered many topics. He claimed to have discovered the cosmic ray in 1896 and invented a way to produce direct current by induction, and made many claims about his mechanical oscillator. Describing the device (which he expected would earn him $100 million within two years) he told reporters that a version of his oscillator had caused an earthquake in his 46 East Houston Street lab and neighboring streets in Lower Manhattan in 1898. He went on to tell reporters his oscillator could destroy the Empire State Building with 5 pounds (2.3 kg) of air pressure. He also proposed using his oscillators to transmit vibrations into the ground. He claimed it would work over any distance and could be used for communication or locating underground mineral deposits, a technique he called "telegeodynamics".

In 1937, at his Grand Ballroom of Hotel New Yorker event, Tesla received the Order of the White Lion from the Czechoslovak ambassador and a medal from the Yugoslav ambassador. On questions concerning the death ray, Tesla stated: "But it is not an experiment ... I have built, demonstrated and used it. Only a little time will pass before I can give it to the world."

Death

Room 3327 of the Hotel New Yorker, where Tesla died
Room 3327 of the Hotel New Yorker, where Tesla died
Commemorative plaque, New Yorker Hotel

In the fall of 1937 at the age of 81, after midnight one night, Tesla left the Hotel New Yorker to make his regular commute to the cathedral and library to feed the pigeons. While crossing a street a couple of blocks from the hotel, Tesla was struck by a moving taxicab and was thrown to the ground. His back was severely wrenched and three of his ribs were broken in the accident. The full extent of his injuries was never known; Tesla refused to consult a doctor, an almost lifelong custom, and never fully recovered.

On 7 January 1943, at the age of 86, Tesla died alone in Room 3327 of the Hotel New Yorker. His body was found by maid Alice Monaghan when she entered Tesla's room, ignoring the "do not disturb" sign that Tesla had placed on his door two days earlier. Assistant medical examiner H.W. Wembley examined the body and ruled that the cause of death had been coronary thrombosis (a type of heart attack).

Two days later the Federal Bureau of Investigation ordered the Alien Property Custodian to seize Tesla's belongings. John G. Trump, a professor at M.I.T. and a well-known electrical engineer serving as a technical aide to the National Defense Research Committee, was called in to analyze the Tesla items. After a three-day investigation, Trump's report concluded that there was nothing which would constitute a hazard in unfriendly hands, stating:

His thoughts and efforts during at least the past 15 years were primarily of a speculative, philosophical, and somewhat promotional character often concerned with the production and wireless transmission of power; but did not include new, sound, workable principles or methods for realizing such results.

In a box purported to contain a part of Tesla's "death ray", Trump found a 45-year-old multidecade resistance box.

On 10 January 1943, New York City mayor Fiorello La Guardia read a eulogy written by Slovene-American author Louis Adamic live over WNYC radio while violin pieces "Ave Maria" and "Tamo daleko" were played in the background. On 12 January, two thousand people attended a state funeral for Tesla at the Cathedral of St. John the Divine in Manhattan. After the funeral, Tesla's body was taken to the Ferncliff Cemetery in Ardsley, New York, where it was later cremated. The following day, a second service was conducted by prominent priests in the Trinity Chapel (today's Serbian Orthodox Cathedral of Saint Sava) in New York City.

Personal life and character

Photograph of Nikola Tesla, a slender, moustachioed man with a thin face and pointed chin.
Tesla c. 1896

Tesla was a lifelong bachelor, who had once explained that his chastity was very helpful to his scientific abilities. In an interview with the Galveston Daily News on 10 August 1924 he stated, "Now the soft-voiced gentlewoman of my reverent worship has all but vanished. In her place has come the woman who thinks that her chief success in life lies in making herself as much as possible like man—in dress, voice and actions..." Although he told a reporter in later years that he sometimes felt that by not marrying, he had made too great a sacrifice to his work, Tesla chose to never pursue or engage in any known relationships, instead finding all the stimulation he needed in his work.

Tesla was asocial and prone to seclude himself with his work. However, when he did engage in social life, many people spoke very positively and admiringly of Tesla. Robert Underwood Johnson described him as attaining a "distinguished sweetness, sincerity, modesty, refinement, generosity, and force". His 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, Julian Hawthorne, wrote, "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".

Tesla was a good friend of Francis Marion Crawford, Robert Underwood Johnson, Stanford White, Fritz Lowenstein, George Scherff, and Kenneth Swezey. In middle age, Tesla became a close friend of Mark Twain; they spent a lot of time together in his lab and elsewhere. Twain notably described Tesla's induction motor invention as "the most valuable patent since the telephone". At a party thrown by actress Sarah Bernhardt in 1896, Tesla met Indian Hindu monk Swami Vivekananda. Vivekananda later wrote that Tesla said he could demonstrate mathematically the relationship between matter and energy, something Vivekananda hoped would give a scientific foundation to Vedantic cosmology. The meeting with Swami Vivekananda stimulated Tesla's interest in Eastern Science, which led to Tesla studying Hindu and Vedic philosophy for a number of years. Tesla later wrote an article titled "Man's Greatest Achievement" using Sanskrit terms akasha and prana to describe the relationship between matter and energy. In the late 1920s, Tesla befriended George Sylvester Viereck, a poet, writer, mystic, and later, a Nazi propagandist. Tesla occasionally attended dinner parties held by Viereck and his wife.

Tesla could be harsh at times and openly expressed disgust for overweight people, such as when he fired a secretary because of her weight. He was quick to criticize clothing; on several occasions, Tesla directed a subordinate to go home and change her dress. When Thomas Edison died in 1931, Tesla contributed the only negative opinion to The New York Times, buried in an extensive coverage of Edison's life:

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.

Tesla became a vegetarian in his later years, living on only milk, bread, honey, and vegetable juices.

Views and beliefs

Tesla c. 1885

On experimental and theoretical physics

Tesla disagreed with the theory of atoms being composed of smaller subatomic particles, stating there was no such thing as an electron creating an electric charge. He believed that if electrons existed at all, they were some fourth state of matter or "sub-atom" that could exist only in an experimental vacuum and that they had nothing to do with electricity. Tesla believed that atoms are immutable—they could not change state or be split in any way. He was a believer in the 19th-century concept of an all-pervasive ether that transmitted electrical energy.

Tesla was generally antagonistic towards theories about the conversion of matter into energy. He was also critical of Einstein's theory of relativity, saying:

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.

In 1935 he described relativity as "a beggar wrapped in purple whom ignorant people take for a king" and said his own experiments had measured the speed of cosmic rays from Arcturus as fifty times the speed of light.

Tesla claimed to have developed his own physical principle regarding matter and energy that he started working on in 1892, and in 1937, at age 81, claimed in a letter to have completed a "dynamic theory of gravity" that " put an end to idle speculations and false conceptions, as that of curved space". He stated that the theory was "worked out in all details" and that he hoped to soon give it to the world. Further elucidation of his theory was never found in his writings.

On society

This article is part of a series on the
Eugenics Movement
Historical trajectory
Pre-war academic proponents
Post-war academic remnants
Pamphlets and manifestos
OrganizationsWithout significant post-war activity

With significant post-war activity

Related

Tesla is widely considered by his biographers to have been a humanist in philosophical outlook. This did not preclude Tesla, like many of his era, from becoming a proponent of an imposed selective breeding version of eugenics.

Tesla expressed the belief that human "pity" had come to interfere with the natural "ruthless workings of nature". Though his argumentation did not depend on a concept of a "master race" or the inherent superiority of one person over another, he advocated for eugenics. 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.

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

Tesla made predictions about the relevant issues of a post-World War I environment in a printed article entitled "Science and Discovery are the great Forces which will lead to the Consummation of the War" (20 December 1914). Tesla believed that the League of Nations was not a remedy for the times and issues.

On religion

Tesla was raised an Orthodox Christian. Later in life he did not consider himself to be a "believer in the orthodox sense", said he opposed religious fanaticism, and said "Buddhism and Christianity are the greatest religions both in number of disciples and in importance." He also said "To me, the universe is simply a great machine which never came into being and never will end" and "what we call 'soul' or 'spirit,' is nothing more than the sum of the functionings of the body. When this functioning ceases, the 'soul' or the 'spirit' ceases likewise."

Literary works

Tesla wrote a number of books and articles for magazines and journals. Among his books are My Inventions: The Autobiography of Nikola Tesla, compiled and edited by Ben Johnston in 1983 from a series of 1919 magazine articles by Tesla which were republished in 1977; The Fantastic Inventions of Nikola Tesla (1993), compiled and edited by David Hatcher Childress; and The Tesla Papers.

Many of Tesla's writings are freely available online, including the article "The Problem of Increasing Human Energy", published in The Century Magazine in 1900, and the article "Experiments with Alternate Currents of High Potential and High Frequency", published in his book Inventions, Researches and Writings of Nikola Tesla.

Legacy and honors

See also: Nikola Tesla in popular culture, List of things named after Nikola Tesla, and List of Nikola Tesla patents
Gilded urn with Tesla's ashes, in his favorite geometric object, a sphere (Nikola Tesla Museum, Belgrade)

In 1952, following pressure from Tesla's nephew, influential Yugoslav politician Sava Kosanović [sr], Tesla's entire estate was shipped to Belgrade in 80 trunks marked N.T. In 1957, Kosanović's secretary Charlotte Muzar transported Tesla's ashes from the United States to Belgrade. The ashes are displayed in a gold-plated sphere on a marble pedestal in the Nikola Tesla Museum. Nikola Tesla's Archive consists of over 160,000 original documents and is included in UNESCO Memory of the World Programme.

Tesla obtained around 300 patents worldwide for his inventions. Some of Tesla's patents are not accounted for, and various sources have discovered some that have lain hidden in patent archives. There are a minimum of 278 known patents issued to Tesla in 26 countries. Many of Tesla's patents were in the United States, Britain, and Canada, but many other patents were approved in countries around the globe. Many inventions developed by Tesla were not put into patent protection.

See also

Notes

Footnotes

  1. Tesla does not mention which professor this was by name, but some sources conclude this was Martin Sekulić.
  2. Tesla's contemporaries remembered that on a previous occasion Machine Works manager Batchelor had been unwilling to give Tesla a $7 a week pay raise
  3. Account comes from a letter Tesla sent in 1938 on the occasion of receiving an award from the National Institute of Immigrant Welfare
  4. Tesla's own experiments led him to erroneously believe Hertz had misidentified a form of conduction instead of a new form of electromagnetic radiation, an incorrect assumption that Tesla held for a couple of decades.

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References

Further reading

Library resources about
Nikola Tesla
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Books

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Journals

  • Pavićević, Aleksandra (2014). "From lighting to dust death, funeral and post mortem destiny of Nikola Tesla". Glasnik Etnografskog instituta SANU. 62 (2): 125–139. doi:10.2298/GEI1402125P. hdl:21.15107/rcub_dais_8218. ISSN 0350-0861.
  • Carlson, W. Bernard, "Inventor of dreams". Scientific American, March 2005 Vol. 292 Issue 3 p. 78(7).
  • Jatras, Stella L., "The genius of Nikola Tesla Archived 30 December 2011 at the Wayback Machine". The New American, 28 July 2003 Vol. 19 Issue 15 p. 9(1)
  • Lawren, B., "Rediscovering Tesla". Omni, March 1988, Vol. 10 Issue 6.
  • Rybak, James P., "Nikola Tesla: Scientific Savant". Popular Electronics, 1042170X, November 1999, Vol. 16, Issue 11.
  • Thibault, Ghislain, "The Automatization of Nikola Tesla: Thinking Invention in the Late Nineteenth Century". Configurations Archived 28 March 2018 at the Wayback Machine, Volume 21, Number 1, Winter 2013, pp. 27–52.
  • Martin, Thomas Commerford, "The Inventions, Researches, and Writings of Nikola Tesla", New York: The Electrical Engineer, 1894 (3rd Ed.); reprinted by Barnes & Noble, 1995
  • Anil K. Rajvanshi, "Nikola Tesla – The Creator of Electric Age", Resonance, March 2007.
  • Roguin, Ariel, "Historical Note: Nikola Tesla: The man behind the magnetic field unit". J. Magn. Reson. Imaging 2004;19:369–374. 2004 Wiley-Liss, Inc.
  • Sellon, J. L., "The impact of Nikola Tesla on the cement industry". Behrent Eng. Co., Wheat Ridge, Colorado. Cement Industry Technical Conference. 1997. XXXIX Conference Record., 1997 IEEE/PC. Page(s) 125–133.
  • Valentinuzzi, M.E., "Nikola Tesla: why was he so much resisted and forgotten?" Inst. de Bioingenieria, Univ. Nacional de Tucuman; Engineering in Medicine and Biology Magazine, IEEE. July/August 1998, 17:4, pp. 74–75.
  • Secor, H. Winfield, "Tesla's views on Electricity and the War", Electrical Experimenter, Volume 5, Number 4 August 1917.
  • Florey, Glen, "Tesla and the Military". Engineering 24, 5 December 2000.
  • 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.
  • Meyl, Konstantin, H. Weidner, E. Zentgraf, T. Senkel, T. Junker, and P. Winkels, Experiments to proof the evidence of scalar waves Tests with a Tesla reproduction. Institut für Gravitationsforschung (IGF), Am Heerbach 5, D-63857 Waldaschaff.
  • Anderson, L. I., "John Stone Stone on Nikola Tesla's Priority in Radio and Continuous Wave Radiofrequency Apparatus". The AWA Review, Vol. 1, 1986, pp. 18–41.
  • Anderson, L. I., "Priority in Invention of Radio, Tesla v. Marconi". Antique Wireless Association monograph, March 1980.
  • Marincic, A., and D. Budimir, "Tesla's contribution to radiowave propagation". Dept. of Electron. Eng., Belgrade Univ. (5th International Conference on Telecommunications in Modern Satellite, Cable and Broadcasting Service, 2001. TELSIKS 2001. pp. 327–331 vol.1)

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