Nikola Tesla

Nikola Tesla was born on 10 July 1856 in Smiljan, then in the Military Frontier of the Austrian Empire and now in Croatia. He was the fourth of five children in a Serbian Orthodox family. His father Milutin was a priest; his mother Đuka Mandić had no formal education but made household tools. In 1862 the family moved to Gospić.

After the gymnasium in Karlovac (1873) he fell seriously ill with cholera. From 1875 he studied on a Military Frontier scholarship at the technical college in Graz, but left in December 1878 without a degree. He then worked as a draftsman in Maribor, attended lectures in Prague as an auditor and in 1881 took a job at the telephone exchange in Budapest.

In 1882 Tesla joined Continental Edison in Paris, where he installed lighting systems and improved dynamos and motors. In June 1884 he emigrated to the United States and worked at the Edison Machine Works in New York. He left after about six months; whether an unpaid bonus was the cause is uncertain, and the familiar anecdotes about Edison rest largely on Tesla's own account.

In 1887 he developed an induction motor for polyphase alternating current using a rotating magnetic field. It has no commutator and therefore wears less. The patent followed in May 1888. The Italian physicist Galileo Ferraris had worked out a similar principle in 1885, so the idea cannot be attributed to Tesla alone. In July 1888 he licensed his patents to Westinghouse.

From the 1890s he worked on the Tesla coil (patented 1891), wireless lighting and the wireless transmission of signals and power. In 1899 he built an experimental station with large coils in Colorado Springs. In 1901 he began the Wardenclyffe Tower on Long Island, backed by $150,000 from J. P. Morgan. His assumption that the Earth could conduct energy at scale proved incorrect.

Beyond engineering, Tesla also held views that are regarded today as discriminatory. In a letter of 3 November 1898 to his friend Katharine Johnson he called a Saturday 'a day of plebeians – drummers, grocerymen, Jews, and other social trilobites'. His biographer Margaret Cheney also describes how he once called one of his secretaries over and hissed: 'Miss! Never trust a Jew!' In the 1930s he moreover openly advocated eugenics.

Tesla worked in the early years of electrification. Cities were acquiring electric lighting, and the companies of Edison, Westinghouse and Thomson-Houston competed fiercely in a capital-intensive market. The 'war of the currents' between Edison's direct current and Westinghouse's alternating current was above all a commercial and publicity rivalry, with patent disputes and campaigns about safety.

The scientific climate was shaped by electromagnetic theory and by Hertz's experiments with radio waves (1886–1888), which Tesla learned of in Paris in 1889. World's fairs, newspapers and wealthy investors such as J. P. Morgan and John Jacob Astor IV determined which inventors were heard, and Tesla was known as a skilled showman.

In the early decades of the 20th century eugenics, the idea that humanity should be 'improved' by controlling reproduction, had broad support among scientists and politicians in Europe and the United States; many American states passed laws for the forced sterilisation of psychiatric patients and convicts, among others. Tesla shared these views. In Liberty magazine (usually dated 9 February 1935, 'as told to' George Sylvester Viereck) he predicted that eugenics would be universally established by 2100, called the sterilisation of 'the criminal and the insane' insufficient and wrote that no one who was not a 'desirable parent' should be permitted to have children.

Westinghouse marketed the polyphase system as the 'Tesla Polyphase System'; its engineers, including Charles Scott and Benjamin Lamme, made the motor practical. The lighting of the 1893 World's Columbian Exposition in Chicago and the Niagara Falls power station, on which Tesla gave advice, made alternating current widely known. Its eventual dominance, however, was the work of many engineers and companies.

Tesla's wireless demonstrations and his radio-controlled boat (1898) contributed to the development of radio technology, but priority in the invention of radio remains disputed. In 1943 the US Supreme Court, in a patent case, restored earlier patents of Lodge, Stone and Tesla; it did not rule on Marconi's claim to have achieved the first radio transmission.

In his final decades Tesla lived in New York hotels and left unpaid bills. At his birthday gatherings with the press, held from 1931, he spoke of new inventions, including in 1934 a 'death ray'. He never publicly disclosed how it worked and no working example is known. He died on 7 January 1943; the medical examiner gave the cause as coronary thrombosis.

After his death US authorities seized his belongings; MIT professor John G. Trump found nothing in them that would be dangerous in unfriendly hands. In 1960 the SI unit of magnetic flux density was named after him, and since the 1990s his popularity has grown strongly.

Stories of free energy, an earthquake machine or suppressed inventions rest largely on Tesla's own claims or later interpretations, without independent confirmation. Historians therefore assess him mainly on his patents, publications and documented experiments.

Alongside his technical legacy stand controversial views: his antisemitic remarks and his advocacy of eugenics, with more extensive sterilisation and restrictions on marriage. Those eugenic ideas matched a then widespread movement that was discredited after the crimes of Nazi Germany. Biographer Margaret Cheney ('Tesla: Man Out of Time', 1981) characterises his antisemitism as sporadic and 'not unusual among gentiles of his time'.