Nikola Tesla

Nikola Tesla (10 July 1856 – 7 January 1943) was a Serbian-American engineer, futurist, and inventor, recognized for his pivotal contributions to the development of the modern alternating current (AC) electricity supply system.

Nikola Tesla (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.

Tesla, born and raised within the Austrian Empire, pursued studies in engineering and physics during the 1870s, though he did not complete a degree. Subsequently, in the early 1880s, he acquired practical expertise in telephony and within the nascent electric power sector at Continental Edison. In 1884, he immigrated to the United States, where he obtained naturalized citizenship. After a brief tenure at the Edison Machine Works in New York City, he established independent ventures. Collaborating with partners who provided financing and marketing, Tesla founded laboratories and enterprises in New York to innovate various electrical and mechanical apparatuses. His AC induction motor and associated polyphase AC patents, licensed by Westinghouse Electric in 1888, generated substantial revenue and formed the foundational element of the polyphase system commercialized by Westinghouse.

Tesla undertook numerous experiments, including those involving mechanical oscillators/generators, electrical discharge tubes, and rudimentary X-ray imaging, with the objective of developing patentable and marketable inventions. He notably constructed a wirelessly controlled boat, representing one of the earliest wirelessly operated vehicles. Tesla gained prominence as an inventor, showcasing his innovations to notable figures and affluent benefactors at his laboratory, and was recognized for his theatrical presentations during public lectures. Throughout the 1890s, his high-voltage, high-frequency power experiments in New York and Colorado Springs focused on concepts for wireless lighting and global wireless electric power distribution. In 1893, he articulated the potential for wireless communication utilizing his devices. Tesla endeavored to implement these concepts practically through his uncompleted Wardenclyffe Tower project, intended as an intercontinental wireless communication and power transmitter; however, the project ceased due to insufficient funding.

Subsequent to the Wardenclyffe project, Tesla pursued a range of inventions during the 1910s and 1920s, achieving varied levels of success. Having depleted the majority of his financial resources, Tesla resided in various New York hotels, accumulating outstanding debts. He passed away in New York City in January 1943. Following his death, Tesla's contributions largely receded from public recognition until 1960, when the General Conference on Weights and Measures designated the International System of Units (SI) measurement for magnetic flux density as the tesla, in his honor. A renewed popular interest in Tesla has emerged since the 1990s. In 2013, Time magazine recognized Tesla as one of the 100 most influential figures in history.

Early Life

Childhood

Nikola Tesla was born on 10 July 1856 in Smiljan, a village located within the Military Frontier of the Austrian Empire (now Croatia), to an ethnic Serb family. His father, Milutin Tesla (1819–1879), served as a priest of the Eastern Orthodox Church. Josif, his paternal uncle, was a lecturer at a military academy and authored several mathematics textbooks.

Tesla's mother, Georgina "Đuka" Mandić (1822–1892), whose father was also an Eastern Orthodox priest, possessed a notable aptitude for crafting domestic tools and mechanical devices, alongside an exceptional capacity for memorizing Serbian epic poems. Despite never receiving a formal education, Đuka's genetic traits and influence were cited by Tesla as the source of his eidetic memory and creative faculties.

Tesla was the fourth of five children. In 1861, he commenced primary education in Smiljan, focusing on German, arithmetic, and religion. The Tesla family relocated in 1862 to the adjacent town of Gospić, where his father served as a parish priest. Nikola subsequently completed both primary and middle school. Prior to acquiring American citizenship, Tesla identified himself in his patent applications as being "of Smiljan, Lika, border country of Austria-Hungary."

Education

In 1870, Tesla relocated to Karlovac to attend the Higher Real Gymnasium, where instruction was conducted in German, a common practice in schools across the Austro-Hungarian Military Frontier. Tesla subsequently documented his growing fascination with the electricity demonstrations conducted by his physics professor. He described these "mysterious phenomena" as igniting a desire "to know more of this wonderful force." His remarkable ability to perform integral calculus mentally led his instructors to suspect him of cheating. Completing a four-year curriculum in just three years, he graduated in 1873.

Following his graduation, Tesla returned to Smiljan, where he contracted cholera, enduring nine months of bedrest and experiencing multiple near-fatal episodes. During a period of profound despair, Tesla's father, who had initially intended for him to join the priesthood, pledged to enroll him in a premier engineering institution upon his recovery. Tesla later recounted reading Mark Twain's early literary works during his convalescence.

The following year, Tesla avoided conscription into the Austro-Hungarian Army in Smiljan by relocating to Tomingaj, a village southeast of Lika, near Gračac. In this region, he explored mountainous terrain, often dressed in hunter's attire. Tesla asserted that this immersion in nature enhanced his physical and mental fortitude. In 1875, he matriculated at the Imperial-Royal Technical College in Graz, supported by a Military Frontier scholarship. Tesla successfully completed nine examinations, almost double the required number, and received a commendation letter from the dean of the technical faculty addressed to his father, declaring, "Your son is a star of first rank." While at Graz, Tesla developed a profound interest in the electricity lectures delivered by Professor Jakob Pöschl. However, by his third year, his academic performance declined, and he departed Graz in December 1878 without graduating. A biographer posits that Tesla neglected his studies and potentially faced expulsion due to gambling and womanizing.

Following his departure from the college, Tesla's family lost contact with him. A rumor circulated among his former classmates that he had drowned in the nearby Mur River; however, in January, one classmate encountered Tesla in Maribor and subsequently informed his family. It was discovered that Tesla had been employed as a draftsman in Maribor, earning 60 florins monthly. In March 1879, Milutin eventually located his son and attempted to persuade him to return home and resume his education in Prague. Tesla was deported to Gospić later that month due to the absence of a residence permit. Tesla's father passed away the following month, on April 17, 1879, at the age of 60, following an unspecified illness.

In January 1880, two of Tesla's uncles financed his relocation from Gospić to Prague, with the intention of him pursuing further studies. However, he arrived too late to matriculate at Charles-Ferdinand University, having neither studied Greek, a prerequisite, nor being proficient in Czech, another mandatory subject. Consequently, he attended philosophy lectures at the university as an auditor but did not receive academic credit for these courses.

The Budapest Telephone Exchange

In 1881, Tesla relocated to Budapest, Hungary, to work for Tivadar Puskás at the Budapest Telephone Exchange, a telegraph company. Upon his arrival, Tesla discovered that the company was still under construction and not yet operational, leading him to accept a position as a draftsman at the Central Telegraph Office. Within several months, the Budapest Telephone Exchange commenced operations, and Tesla was appointed chief electrician. Tesla subsequently detailed numerous enhancements he implemented for the Central Station equipment, notably an improved telephone repeater or amplifier.

Employment at Edison

In 1882, Tivadar Puskás secured another employment opportunity for Tesla in Paris with the Continental Edison Company. Tesla commenced work in the nascent electric power utility sector, focusing on the citywide installation of large-scale indoor incandescent lighting systems. The company comprised several subdivisions, and Tesla was assigned to the Société Electrique Edison, the division responsible for lighting system installation in the Ivry-sur-Seine suburb of Paris. This role provided him with extensive practical experience in electrical engineering. His advanced proficiency in engineering and physics attracted managerial attention, leading to his involvement in designing and constructing enhanced versions of generating dynamos and motors.

Relocation to the United States

In 1884, Charles Batchelor, an Edison manager who had supervised the Paris installation, was reassigned to the United States to manage the Edison Machine Works, a manufacturing division in New York City. Batchelor subsequently requested Tesla's relocation to the United States. By June 1884, Tesla had emigrated and immediately began working at the Machine Works, located on Manhattan's Lower East Side. This facility was a crowded operation employing hundreds of machinists, laborers, managerial staff, and 20 "field engineers" tasked with constructing the city's substantial electric utility. Tesla's responsibilities mirrored his previous work in Paris, involving troubleshooting installations and enhancing generator efficiency.

According to historian W. Bernard Carlson, Tesla likely encountered company founder Thomas Edison on only a few occasions. One such meeting is documented in Tesla's autobiography: after an all-night effort to repair damaged dynamos on the ocean liner SS Oregon, Tesla encountered Batchelor and Edison. Edison reportedly quipped about their "Parisian" being out all night. Upon learning that Tesla had spent the night repairing the Oregon, Edison remarked to Batchelor, "this is a damned good man." Among Tesla's assignments was the development of an arc lamp-based street lighting system. Although arc lighting was the predominant form of street illumination, its high voltage requirements rendered it incompatible with Edison's low-voltage incandescent system, leading to lost contracts for the company in various municipalities. Tesla's designs for this system were ultimately not implemented, potentially due to advancements in incandescent street lighting technology or an existing installation agreement Edison had with an arc lighting firm.

Tesla's tenure at the Machine Works concluded after approximately six months. The precise circumstances precipitating his departure remain ambiguous. Speculation suggests his resignation may have stemmed from an unreceived bonus, either for his generator redesigns or for the arc lighting system that was ultimately abandoned. Tesla had prior disagreements with the Edison company regarding unpaid bonuses he believed were due to him. In his autobiography, Tesla recounted that the manager of the Edison Machine Works offered a $50,000 bonus for designing "twenty-four different types of standard machines," which he later described as "a practical joke." Subsequent accounts attribute this offer and its retraction directly to Thomas Edison, who reportedly quipped, "Tesla, you don't understand our American humor." The substantial sum of the alleged bonus in both narratives has been deemed improbable, given Machine Works manager Batchelor's reputation for parsimony and the company's lack of such significant liquid assets (equivalent to $1,791,667 in contemporary value). Tesla's diary offers only a singular, terse entry concerning the termination of his employment, a note scrawled across pages dated December 7, 1884, to January 4, 1885, stating, "Good By to the Edison Machine Works."

Tesla Electric Light and Manufacturing

Shortly after his departure from the Edison company, Tesla commenced efforts to patent an arc lighting system, potentially the same design he had developed during his employment there. In March 1885, he consulted with patent attorney Lemuel W. Serrell, who also represented Edison, to assist with patent submissions. Serrell subsequently introduced Tesla to two businessmen, Robert Lane and Benjamin Vail. These individuals agreed to finance an arc lighting manufacturing and utility enterprise under Tesla's name, designated the Tesla Electric Light and Manufacturing Company. Throughout the remainder of the year, Tesla secured patents, including one for an improved DC generator—his inaugural patents issued in the United States—and oversaw the construction and installation of the system in Rahway, New Jersey.

The investors demonstrated minimal enthusiasm for Tesla's concepts regarding novel alternating current motors and electrical transmission apparatus. Once the utility became operational in 1886, they concluded that the manufacturing sector of the business was excessively competitive and chose to operate solely as an electric utility. Consequently, they established a new utility company, thereby abandoning Tesla's enterprise and rendering the inventor indigent. Tesla also forfeited control of his generated patents, having assigned them to the company in exchange for equity. He was compelled to undertake various electrical repair tasks and manual labor as a ditch digger, earning $2 per day. Reflecting later in life, Tesla characterized this period of 1886 as one of significant adversity, noting, "My high education in various branches of science, mechanics and literature seemed to me like a mockery."

AC and the induction motor

In late 1886, Nikola Tesla established a partnership with Alfred S. Brown, a Western Union superintendent, and Charles Fletcher Peck, a New York attorney. These individuals possessed expertise in corporate formation and the commercialization of inventions and patents. Recognizing Tesla's innovative concepts for electrical apparatus, including a thermo-magnetic motor, they committed to providing financial support and managing his patent portfolio. Consequently, in April 1887, they co-founded the Tesla Electric Company. The foundational agreement stipulated that profits derived from patents would be allocated as follows: 1⁄3 to Tesla, §78§⁄§910§ to Peck and Brown, and §1314§⁄§1516§ for ongoing research and development. A laboratory was established for Tesla at 89 Liberty Street in Manhattan, where he focused on refining existing and pioneering new electric motors, generators, and various other electrical devices.

During 1887, Tesla engineered an induction motor designed to operate on alternating current (AC), a power distribution system gaining rapid adoption across Europe and the United States due to its inherent benefits for long-distance, high-voltage transmission. This motor incorporated polyphase current to generate a rotating magnetic field, which actuated the motor's rotation—a principle Tesla asserted he had conceptualized in 1882. Patented in May 1888, this groundbreaking electric motor featured a straightforward, self-starting mechanism that eliminated the need for a commutator, thereby preventing sparking and mitigating the substantial maintenance requirements associated with servicing and replacing mechanical brushes.

In parallel with securing the patent, Peck and Brown orchestrated a comprehensive publicity campaign for the motor. This initiative commenced with independent testing to validate its functional superiority, followed by the dissemination of press releases to technical publications, ensuring articles would coincide with the patent's issuance. Physicist William Arnold Anthony, who conducted the motor's testing, and Thomas Commerford Martin, editor of Electrical World magazine, facilitated Tesla's public demonstration of his AC motor on May 16, 1888, at the American Institute of Electrical Engineers. Engineers from the Westinghouse Electric & Manufacturing Company subsequently informed George Westinghouse of Tesla's viable AC motor and associated power system, a critical component for the alternating current infrastructure Westinghouse was actively promoting. Although Westinghouse investigated a similar commutator-less, rotating magnetic field-based induction motor developed in 1885 and presented in March 1888 by Italian physicist Galileo Ferraris, he ultimately concluded that Tesla's patent would likely establish market dominance.

In July 1888, Brown and Peck finalized a licensing agreement with George Westinghouse concerning Tesla's polyphase induction motor and transformer designs. The terms included a payment of $60,000 in cash and stock, alongside a royalty of $2.50 for each AC horsepower generated by every motor. Additionally, Westinghouse engaged Tesla for a one-year consultancy at the Westinghouse Electric & Manufacturing Company's Pittsburgh laboratories, offering a substantial monthly remuneration of $2,000 (equivalent to $71,700 in contemporary value).

Throughout that year, Tesla was engaged in Pittsburgh, contributing to the development of an alternating current system intended to power the city's streetcar network. This period proved challenging for him, marked by disagreements with other Westinghouse engineers regarding the optimal implementation of AC power. Although they initially adopted Tesla's proposed 60-cycle AC system, designed to align with his motor's operational frequency, it was subsequently determined to be impractical for streetcars due to the constant-speed characteristic of Tesla's induction motor. Consequently, a direct current (DC) traction motor was ultimately employed.

Market turmoil

The public demonstration of Tesla's induction motor and Westinghouse's subsequent patent licensing, both occurring in 1888, coincided with a period of intense rivalry among electric utility companies. The three dominant corporations—Westinghouse, Edison, and Thomson-Houston Electric Company—were simultaneously pursuing expansion within a capital-intensive industry while engaging in aggressive financial competition. This era was further characterized by the "War of Currents," a propaganda campaign wherein Edison Electric asserted the superiority and safety of its direct current system over Westinghouse's alternating current system, with Thomson-Houston occasionally aligning with Edison. Such market pressures constrained Westinghouse's financial capital and engineering capacity, precluding the immediate comprehensive development of Tesla's motor and its associated polyphase system.

Two years subsequent to the execution of the Tesla contract, Westinghouse Electric encountered significant financial difficulties. The impending failure of Barings Bank in London precipitated the financial panic of 1890, prompting investors to recall their loans from Westinghouse Electric. This abrupt liquidity crisis compelled the company to restructure its outstanding debts. The new creditors imposed stringent conditions, requiring Westinghouse to curtail what they perceived as extravagant expenditures on corporate acquisitions, research initiatives, and patent rights, specifically targeting the per-motor royalty stipulated in the Tesla contract. Concurrently, the Tesla induction motor remained commercially unviable and was still undergoing developmental stages. Despite the scarcity of operational induction motors and the even greater rarity of the requisite polyphase power systems, Westinghouse was obligated to pay an annual guaranteed royalty of $15,000.

In early 1891, George Westinghouse candidly communicated his financial predicaments to Tesla, indicating that failure to satisfy the demands of his creditors would result in his loss of control over Westinghouse Electric, thereby forcing Tesla to negotiate directly with the bankers for future royalty collections. Recognizing the strategic benefits of Westinghouse's continued advocacy for the motor, Tesla consented to absolve the company from the royalty payment provision within their agreement. Subsequently, six years later, Westinghouse acquired Tesla's patent for a one-time payment of $216,000, integrating this acquisition into a broader patent-sharing accord established with General Electric, a corporation formed through the 1892 consolidation of Edison and Thomson-Houston.

Laboratories in New York

The revenue generated from licensing his alternating current (AC) patents provided Tesla with financial independence, affording him the resources and leisure to pursue his scientific interests. In 1889, Tesla relocated from the Liberty Street premises leased by Peck and Brown, subsequently operating from various workshop and laboratory facilities across Manhattan for the ensuing twelve years. These locations encompassed a laboratory at 175 Grand Street (1889–1892), the fourth floor of 33–35 South Fifth Avenue (1892–1895), and the sixth and seventh floors of 46 & 48 East Houston Street (1895–1902).

The Tesla Coil

During the summer of 1889, Tesla attended the Exposition Universelle in Paris, where he became acquainted with Heinrich Hertz's experimental findings from 1886–1888, which conclusively demonstrated the existence of electromagnetic radiation, including radio waves. While replicating and subsequently extending these experiments, Tesla attempted to energize a Ruhmkorff coil using a high-speed alternator he had designed for an enhanced arc lighting system. However, he observed that the high-frequency current caused the iron core to overheat and the insulation between the primary and secondary windings within the coil to melt. To mitigate this issue, Tesla devised his "oscillating transformer," which incorporated an air gap instead of conventional insulating material between the primary and secondary windings, along with an adjustable iron core that could be positioned variably within or outside the coil. This device, subsequently known as the Tesla coil, was designed to generate high-voltage, low-current, high-frequency alternating-current electricity. This resonant transformer circuit became integral to his subsequent research on wireless power transmission.

Wireless Illumination Systems

Subsequent to 1890, Tesla conducted experiments involving power transmission via inductive and capacitive coupling, utilizing high alternating current (AC) voltages produced by his Tesla coil. He endeavored to create a wireless lighting system predicated on near-field inductive and capacitive coupling, performing numerous public demonstrations where he illuminated Geissler tubes and incandescent light bulbs from a distance across a stage. Throughout the majority of that decade, he dedicated efforts to refining variations of this novel illumination method, supported by various investors; however, none of these undertakings successfully commercialized his discoveries.

In 1893, during presentations at St. Louis, Missouri, the Franklin Institute in Philadelphia, Pennsylvania, and the National Electric Light Association, Tesla asserted to his audience that a system akin to his own could ultimately transmit "intelligible signals or perhaps even power to any distance without the use of wires" by propagating it through the Earth.

On July 30, 1891, at the age of 35, Tesla acquired naturalized citizenship of the United States. During the same year, he secured a patent for his Tesla coil. From 1892 to 1894, he held the position of vice-president for the American Institute of Electrical Engineers, an organization that, alongside the Institute of Radio Engineers, served as a precursor to the contemporary Institute of Electrical and Electronics Engineers (IEEE).

The Polyphase System and the Columbian Exposition

By early 1893, Westinghouse engineers Charles F. Scott and Benjamin G. Lamme had significantly advanced the development of an efficient iteration of Tesla's induction motor. Lamme's innovation of a rotary converter enabled the requisite polyphase system to integrate seamlessly with existing single-phase AC and DC infrastructures. Consequently, Westinghouse Electric gained the capacity to supply electricity to a broader customer base and began marketing its polyphase AC system under the designation "Tesla Polyphase System." The company asserted that Tesla's patents established their priority over competing polyphase AC technologies.

Westinghouse Electric extended an invitation to Tesla to participate in the 1893 World's Columbian Exposition in Chicago, where the company occupied a substantial exhibition area within the "Electricity Building." Westinghouse Electric secured the contract to illuminate the Exposition using alternating current, marking a pivotal moment in the evolution of AC power. Through this event, the company effectively showcased to the American populace the safety, reliability, and efficiency inherent in a polyphase alternating current system, which also powered other AC and DC exhibits at the fair.

A dedicated exhibition area was established to showcase diverse configurations and prototypes of Tesla's induction motor. The underlying principle of the rotating magnetic field, which propelled these devices, was elucidated through a sequence of demonstrations. These included an Egg of Columbus, which utilized the two-phase coil characteristic of an induction motor to rotate a copper egg, causing it to stand upright.

Tesla attended the Exposition for one week during its six-month duration, participating in the International Electrical Congress and conducting several demonstrations at the Westinghouse exhibit. A specifically darkened chamber was prepared where Tesla presented his wireless lighting system, employing a demonstration previously conducted across America and Europe. This involved utilizing high-voltage, high-frequency alternating current to illuminate wireless gas-discharge lamps.

Steam-Powered Oscillating Generator

At the International Electrical Congress, held in the Agriculture Hall of the Columbian Exposition, Tesla unveiled his steam-powered reciprocating electricity generator, which he had patented that year. He posited this device as a superior method for generating alternating current. In its operation, steam was introduced into the oscillator, exiting through a series of ports, thereby driving a piston connected to an armature in a reciprocating motion. The magnetic armature vibrated rapidly, generating an alternating magnetic field, which in turn induced alternating electric current in adjacent wire coils. While this design eliminated the complex components typically found in steam engine/generator systems, it ultimately did not gain traction as a viable engineering solution for electricity generation.

Consultation Regarding Niagara

In 1893, Edward Dean Adams, chairman of the Niagara Falls Cataract Construction Company, solicited Tesla's expert assessment regarding the optimal system for transmitting power generated at the falls. For several years prior, numerous proposals and competitive bids had been evaluated concerning this objective. Proposed systems from various U.S. and European firms included two-phase and three-phase AC, high-voltage DC, and compressed air. Adams specifically requested Tesla's insights into the contemporary status of all contending systems. Tesla recommended a two-phase system as the most dependable option, noting the existence of a Westinghouse system capable of illuminating incandescent bulbs with two-phase alternating current. Consequently, the company awarded a contract to Westinghouse Electric for the construction of a two-phase AC generating system at Niagara Falls, a decision influenced by Tesla's counsel and Westinghouse's demonstration at the Columbian Exposition. Concurrently, General Electric received an additional contract for the development of the AC distribution system.

The Nikola Tesla Company

In 1895, Edward Dean Adams, significantly impressed by his observations during a tour of Tesla's laboratory, consented to assist in establishing the Nikola Tesla Company. This entity was formed to finance, develop, and commercialize a range of Tesla's existing patents and inventions, alongside new innovations. Alfred Brown joined the venture, contributing patents previously developed under Peck and Brown. The company's board of directors was further constituted by William Birch Rankine and Charles F. Coaney.

On March 13, 1895, a fire erupted in the South Fifth Avenue building housing Tesla's laboratory. Originating in the basement, the conflagration intensified to such a degree that Tesla's fourth-floor laboratory was consumed by flames and subsequently collapsed onto the second floor. This catastrophic event significantly impeded Tesla's ongoing research endeavors, obliterating a substantial collection of preliminary notes, research materials, experimental models, and demonstration apparatus, many of which had been showcased at the 1893 World's Columbian Exposition. In a statement to The New York Times, Tesla expressed profound distress, remarking, "I am in too much grief to talk. What can I say?"

X-ray Experimentation

Commencing in 1894, Tesla initiated investigations into what he termed "invisible" radiant energy, prompted by observations of damaged photographic film in his laboratory during earlier experiments (a phenomenon subsequently identified as "Roentgen rays" or "X-rays"). His initial experimental work involved Crookes tubes, which are characterized as cold cathode electrical discharge tubes. Tesla potentially captured an X-ray image inadvertently, weeks prior to Wilhelm Röntgen's December 1895 public announcement of X-ray discovery, during an attempt to photograph Mark Twain illuminated by a Geissler tube, an antecedent form of gas discharge tube. The resulting image, however, solely depicted the metallic locking screw of the camera lens.

By March 1896, Tesla was actively engaged in X-ray imaging experiments, during which he developed a high-energy, single-terminal vacuum tube devoid of a target electrode, powered by the output of a Tesla coil (the contemporary scientific term for the radiation generated by such a device is bremsstrahlung or braking radiation). Within the scope of his investigations, Tesla conceived multiple experimental configurations for X-ray generation. Tesla asserted that his circuitry would enable the "instrument will ... enable one to generate Roentgen rays of much greater power than obtainable with ordinary apparatus".

Tesla documented the inherent hazards associated with operating his circuits and single-node X-ray-generating apparatus. Across numerous early investigative notes concerning this phenomenon, he ascribed observed skin damage to a multitude of factors. Initially, he posited that cutaneous damage resulted not from the Roentgen rays themselves, but primarily from ozone produced upon contact with the skin, and secondarily from nitrous acid. Tesla erroneously theorized that X-rays constituted longitudinal waves, akin to those observed in plasmas. Such plasma waves are known to manifest within force-free magnetic fields.

Radio Remote Control

In 1898, at an electrical exhibition held in Madison Square Garden, Tesla publicly showcased a boat controlled by a coherer-based radio system, which he designated as a "telautomaton". Tesla subsequently attempted to market this concept to the U.S. military as a prototype radio-controlled torpedo; however, the military evinced minimal interest. On May 13, 1899, during his journey to Colorado Springs, Tesla seized an additional opportunity to present "Teleautomatics" in an address delivered to a Commercial Club meeting in Chicago.

Wireless Power Transmission

Between the 1890s and 1906, Tesla dedicated substantial time and financial resources to a series of projects aimed at pioneering the wireless transmission of electrical power. During this period, no viable method existed for the long-distance wireless transmission of communication signals, much less significant quantities of electrical power. Tesla's early investigations into radio waves led him to conclude that certain aspects of the prevailing research, particularly that conducted by Hertz, were erroneous. Tesla observed that, even assuming the veracity of radio wave theories, they would be impractical for his objectives, as this form of "invisible light" would attenuate over distance akin to other radiation and propagate linearly into space, thereby becoming "hopelessly lost". He subsequently pursued the concept of long-distance electricity conduction through the Earth or its atmosphere, initiating experiments to validate this hypothesis, which included the construction of a substantial resonance transformer magnifying transmitter within his East Houston Street laboratory.

Colorado Springs Research

In 1899, Tesla established an experimental station in Colorado Springs at a high altitude to further investigate the conductive properties of low-pressure air. This location enabled him to safely operate significantly larger coils than those used in his New York laboratory, with the El Paso Electric Light Company providing alternating current without charge. To finance these experiments, he secured a $100,000 investment (equivalent to $3,870,000 in contemporary currency) from John Jacob Astor IV, who subsequently became a majority shareholder in the Nikola Tesla Company. Upon his arrival, Tesla informed journalists of his intention to conduct wireless telegraphy experiments, aiming to transmit signals from Pikes Peak to Paris.

During his time there, Tesla conducted experiments with a substantial coil operating in the megavolt range, generating artificial lightning and thunder with discharges reaching millions of volts and lengths up to 135 feet (41 m). On one occasion, this activity inadvertently caused the El Paso generator to burn out, resulting in a power outage. His observations of the electronic noise produced by lightning strikes led him to the erroneous conclusion that the entire Earth could serve as a conductor for electrical energy.

While working in his laboratory, Tesla detected anomalous signals from his receiver, which he theorized might represent communications from an extraterrestrial source. He referenced these observations in a December 1899 letter to a reporter and again in December 1900 to the Red Cross Society. Journalists sensationalized these reports, promptly concluding that Tesla was receiving signals from Mars. Tesla elaborated on these signals in a 9 February 1901 Collier's Weekly article titled "Talking With Planets," stating that it was not immediately evident to him that he was perceiving "intelligently controlled signals" and positing that these signals could originate from Mars, Venus, or other celestial bodies.

Tesla had an arrangement with the editor of The Century Magazine to publish an article detailing his discoveries. The magazine dispatched a photographer to Colorado to document the ongoing work. The resulting article, "The Problem of Increasing Human Energy," was featured in the June 1900 issue. Although Tesla articulated the perceived advantages of his proposed wireless system, the piece was characterized more as an extensive philosophical discourse than a clear scientific exposition of his endeavors.

Wardenclyffe

In New York, Tesla actively sought investors for what he envisioned as a practical wireless transmission system, engaging them at venues such as the Waldorf-Astoria's Palm Garden (where he resided), The Players Club, and Delmonico's. By March 1901, he secured $150,000 (equivalent to $5,805,000 in contemporary currency) from J. P. Morgan, granting Morgan a 51% stake in any resulting wireless patents. Subsequently, Tesla commenced planning the Wardenclyffe Tower facility, intended for construction in Shoreham, New York, situated 100 miles (161 km) east of the city on the North Shore of Long Island.

By July 1901, Tesla had augmented his designs to construct a more potent transmitter, aiming to surpass Marconi's radio-based system, which Tesla considered derivative of his own work. However, in December 1901, Marconi successfully transmitted the letter S from England to Newfoundland, thereby preceding Tesla in achieving such a transatlantic transmission. Consequently, in June 1902, Tesla relocated his laboratory operations from Houston Street to Wardenclyffe.

Wall Street investors favored Marconi's system, leading to a shift in public opinion as some press outlets began to denounce Tesla's project as a deception. The Wardenclyffe initiative ceased operations in 1905, a factor that biographer Marc J. Seifer suggests may have contributed to Tesla's suspected nervous breakdown in 1906. To settle his accumulating debts at the Waldorf-Astoria, which ultimately totaled $20,000 (equivalent to $642,900 in contemporary currency), Tesla mortgaged the Wardenclyffe property.

Later years

Following the closure of Wardenclyffe, Tesla persistently corresponded with J. P. Morgan; subsequent to Morgan's death, Tesla appealed to his son, Jack Morgan, in an attempt to secure additional project funding. In 1906, Tesla established offices at 165 Broadway in Manhattan, endeavoring to generate further capital through the development and commercialization of his patents. His professional addresses included the Metropolitan Life Tower from 1910 to 1914, a brief rental period at the Woolworth Building from which he departed due to financial constraints, and then office space at 8 West 40th Street from 1915 to 1925. After relocating to 8 West 40th Street, Tesla was effectively insolvent, as most of his patents had expired, and he encountered difficulties with his nascent inventions.

Bladeless Turbine

On his 50th birthday in 1906, Tesla demonstrated a bladeless turbine generating 200 horsepower (150 kilowatts) at 16,000 rpm. Subsequently, between 1910 and 1911, several of his bladeless turbine engines, ranging from 100 to 5,000 hp, underwent testing at the Waterside Power Station in New York. Tesla collaborated with various corporations, including Allis-Chalmers in Milwaukee from 1919 to 1922. He licensed the concept to a precision instrument manufacturer, leading to its application in luxury automobile speedometers and other instrumentation.

Wireless Litigation

Upon the outbreak of World War I, British forces severed the transatlantic telegraph cable connecting the United States and Germany to regulate information flow between the two nations. Concurrently, efforts were made to suppress German wireless communication with the U.S. by instigating a patent infringement lawsuit from the U.S. Marconi Company against the German radio firm Telefunken. Telefunken engaged physicists Jonathan Zenneck and Karl Ferdinand Braun for their defense and retained Tesla as an expert witness for two years at a monthly fee of $1,000. The case ultimately stalled and became moot following the U.S. entry into the war against Germany in 1917.

In 1915, Tesla initiated a lawsuit against the Marconi Company, alleging infringement of his wireless tuning patents. While Marconi's initial radio patent had been granted in the U.S. in 1897, his 1900 patent application for radio transmission enhancements faced multiple rejections due to infringement on existing patents, including two of Tesla's 1897 wireless power tuning patents, before its eventual approval in 1904. Tesla's 1915 case did not advance; however, in a related proceeding where the Marconi Company sued the U.S. government for WWI patent infringements, a 1943 Supreme Court of the United States decision reinstated the earlier patents of Oliver Lodge, John Stone, and Tesla. The Court clarified that its ruling did not affirm Marconi's claim as the pioneer of radio transmission, but rather, because Marconi's claims to specific patented improvements were questionable, the company could not assert infringement on those particular patents.

Other Concepts

Tesla endeavored to commercialize several devices predicated on ozone production. These included the 1900 Tesla Ozone Company, which marketed an 1896 patented device based on his Tesla coil, designed to bubble ozone through various oils to create a therapeutic gel. A few years later, he attempted to develop a variant of this technology for use as a hospital room sanitizer.

He posited that applying electricity to the brain could augment intelligence. In 1912, he devised "a plan to make dull students bright by saturating them unconsciously with electricity," involving the wiring of schoolroom walls and "saturating [the schoolroom] 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.'" This proposal received at least provisional approval from William H. Maxwell, then superintendent of New York City schools.

In the August 1917 edition of the magazine The Electrical Experimenter, Tesla theorized that electricity could be employed for submarine detection by utilizing the reflection of an "electric ray" of "tremendous frequency," with the resulting signal displayed on a fluorescent screen. This system has been noted for its superficial resemblance to modern radar. However, Tesla's premise that high-frequency radio waves would penetrate water proved incorrect. Émile Girardeau, a key figure in the development of France's first radar system in the 1930s, observed in 1953 that Tesla's general assertion regarding the necessity of a very strong, high-frequency signal was accurate. Girardeau remarked, "[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 was granted 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" during flight until it operated as a conventional aircraft. Tesla estimated this impractical design would retail for under $1,000.

Living Circumstances

From 1900, Tesla resided at the Waldorf Astoria Hotel in New York City, where he accrued substantial debts. In 1922, he relocated to the St. Regis Hotel, initiating a recurring pattern of moving to different hotels every few years and leaving unpaid bills.

Tesla routinely fed pigeons, initially at his hotel window, and actively rehabilitated injured birds. He claimed daily visits from a particular injured white pigeon, for which he expended over $2,000 (equivalent to $38,470 in 2025), including a custom-built device to support its healing wing and leg. However, his accumulating unpaid bills and complaints regarding the pigeons' mess led to his eviction from the St. Regis in 1923. He was subsequently compelled to vacate the Hotel Pennsylvania in 1930 and the Hotel Governor Clinton in 1934, also residing briefly at the Hotel Marguery. In 1934, Tesla relocated to the Hotel New Yorker. Concurrently, the Westinghouse Electric & Manufacturing Company commenced monthly payments of $125 (equivalent to $3,010 in 2025), in addition to covering his rent. The precise circumstances surrounding this arrangement remain subject to varying accounts. Several sources suggest that Westinghouse was apprehensive, or potentially forewarned, regarding adverse publicity stemming from the destitute living conditions of their former prominent inventor. This payment was reportedly structured as a "consulting fee" to circumvent Tesla's reluctance to accept charitable assistance. Biographer Marc Seifer characterized these Westinghouse payments as a form of "unspecified settlement."

Annual Birthday Press Conferences

In 1931, Kenneth M. Swezey, a journalist with whom Tesla maintained a friendship, organized a celebration for the inventor's 75th birthday. Tesla garnered felicitations from prominent figures in science and engineering, including Albert Einstein, and was featured prominently on the cover of Time magazine. The accompanying caption, "All the world's his power house," highlighted his significant contributions to electrical power generation. The success of this event prompted Tesla to establish it as an annual tradition, during which he presented an elaborate array of food and beverages, including culinary creations of his own design. He extended invitations to the press to showcase his inventions and recount narratives of his past exploits, articulate his views on current events, and present occasionally perplexing assertions.

During the 1932 event, Tesla asserted the invention of a motor powered by cosmic rays. In 1933, at the age of 77, Tesla informed journalists that, following 35 years of research, he was nearing the demonstration of a novel energy form. He posited an energy theory "violently opposed" to Einsteinian physics, which could be harnessed by an apparatus characterized by low operational costs and a 500-year lifespan. Furthermore, he reported ongoing efforts to transmit individualized private radio wavelengths, achieve metallurgical breakthroughs, and develop a method for retinal photography to record cognitive processes.

At the 1934 occasion, Tesla informed reporters of his design for a superweapon, which he asserted would eradicate warfare. This device was commonly referred to as his "death beam" or "death ray." Contemporary reports cited Tesla's assertions that it functioned as a defensive weapon, capable of safeguarding national borders, annihilating an invading army at a range of 200 miles, and neutralizing a fleet of 10,000 enemy aircraft 250 miles distant. Tesla designated the weapon "Teleforce" at his 1940 birthday meeting but never publicly disclosed its operational mechanisms. The United States suspected Tesla intended to market the weapon to the League of Nations. Subsequently, amidst escalating global tensions, Tesla transmitted diagrams to the U.S. War Department, the United Kingdom, the Soviet Union, and Yugoslavia. Plans discovered in 1984 within the Nikola Tesla Museum archive in Belgrade detailed a device employing a method of charging tungsten or mercury slugs to millions of volts and directing them in streams (via electrostatic repulsion) through an array of open-ended gas-jet-sealed vacuum tubes.

At his 79th birthday celebration in 1935, Tesla addressed a variety of subjects. He asserted the discovery of cosmic rays in 1896, the invention of an inductive method for generating direct current, and presented numerous claims regarding his mechanical oscillator. While describing the device, which he anticipated would generate $100 million within two years, he informed journalists that a variant of his oscillator had purportedly induced an earthquake in his 46 East Houston Street laboratory and adjacent areas of Lower Manhattan in 1898. He further claimed that his oscillator possessed the capability to demolish the Empire State Building using merely 5 pounds (2.3 kg) of air pressure. Additionally, he proposed employing his oscillators for the transmission of vibrations into the earth. He asserted its efficacy over any distance, suggesting its application for communication or the detection of subterranean mineral deposits, a method he termed "telegeodynamics."

In 1937, during an event held in the Grand Ballroom of the Hotel New Yorker, Tesla was awarded the Order of the White Lion by the Czechoslovak ambassador and a medal by the Yugoslav ambassador. Responding to inquiries about the "death ray," Tesla declared, "This is not merely an experiment... I have constructed, demonstrated, and utilized it. A brief period remains before I can present it to the world."

Accolades

Tesla was the recipient of numerous medals and distinctions, including:

• Elliott Cresson Medal (Franklin Institute, 1894)
• Grand Cross of the Order of Prince Danilo I (Montenegro, 1895)
• Member of the American Philosophical Society (U.S., 1896)
• AIEE Edison Medal (Institute of Electrical and Electronics Engineers, U.S., 1916)
• Grand Cross of the Order of St. Sava (Yugoslavia, 1926)
• John Scott Medal (Franklin Institute & Philadelphia City Council, U.S., 1934)
• Order of the White Eagle (Yugoslavia, 1936)
• Grand Cross of the Order of the White Lion (Czechoslovakia, 1937)

Demise

In the autumn of 1937, at the age of 81, Tesla departed the Hotel New Yorker late one night for his customary routine of visiting St. Patrick's Cathedral and the Public Library to feed pigeons. While traversing a street a few blocks from the hotel, Tesla was struck by a moving taxicab and consequently fell to the ground. The incident resulted in a severe wrenching of his back and the fracture of three ribs. The complete scope of his injuries remained undetermined, as Tesla, adhering to an almost lifelong practice, declined medical consultation and never achieved a full recovery.

On the evening of January 7, 1943, at the age of 86, Tesla passed away alone in his hotel room. His remains were discovered the following day by a maid who entered his room, disregarding a "do not disturb" sign that had been affixed to his door three days prior. An assistant medical examiner conducted an examination of the body, estimating the time of death at 10:30p.m. and determining coronary thrombosis as the cause.

Given the context of World War II, the U.S. government expressed apprehension that Tesla's possessions, particularly any plans for a purported beam weapon, might be transferred to his nephew, Sava Kosanović, an exiled Yugoslav politician who could potentially provide them to adversaries of the United States. As Kosanović was not a U.S. citizen, the Federal Bureau of Investigation requested the Office of Alien Property Custodian to confiscate Tesla's effects two days subsequent to his death. John G. Trump, an electrical engineering professor at MIT and a technical aide to the National Defense Research Committee, was summoned to analyze Tesla's belongings. Following a three-day inquiry, Trump's report concluded that no items were present that would "constitute a hazard in unfriendly hands." Within a container alleged to hold a component of Tesla's "death ray," Trump discovered a 45-year-old multidecade resistance box.

On January 10, 1943, Fiorello La Guardia, the mayor of New York City, delivered a eulogy for Tesla at his funeral, held at the Cathedral of St. John the Divine.

Personal Life and Disposition

Tesla remained a lifelong bachelor, having once articulated that his celibacy significantly contributed to his scientific capabilities. In an interview published in the Galveston Daily News on August 10, 1924, he remarked, "The soft-voiced gentlewoman of my reverent worship has now almost disappeared. She has been replaced by the woman who believes her primary life's success resides in emulating man as closely as possible—in attire, vocalization, and conduct..." He later confided to a reporter that he occasionally felt his decision not to marry constituted an excessive sacrifice for his professional endeavors.

Tesla maintained friendships with Francis Marion Crawford, Robert Underwood Johnson, Stanford White, Fritz Lowenstein, George Scherff, and Kenneth Swezey. In his middle age, Tesla cultivated a close friendship with Mark Twain; they spent considerable time together in his laboratory and other locations. Twain famously characterized Tesla's induction motor invention as "the most valuable patent since the telephone." At a party hosted by actress Sarah Bernhardt in 1896, Tesla encountered the Indian Hindu monk Swami Vivekananda. Vivekananda subsequently documented Tesla's assertion that he could mathematically demonstrate the relationship between matter and energy, a concept Vivekananda believed could provide a scientific basis for Vedantic cosmology. This meeting with Swami Vivekananda catalyzed Tesla's engagement with Eastern Science, prompting his study of Hindu and Vedic philosophy for several years. Tesla later authored an article titled "Man's Greatest Achievement," incorporating the Sanskrit terms akasha and prana to describe the relationship between matter and energy. In the late 1920s, Tesla established a friendship with George Sylvester Viereck, a poet, writer, mystic, and later a Nazi propagandist. Tesla was an occasional guest at dinner parties hosted by Viereck and his wife.

Tesla exhibited a sometimes severe demeanor, openly voicing his aversion to individuals who were overweight, exemplified by his dismissal of a secretary due to her physical size. He was prone to critiquing attire; on several occasions, Tesla instructed a subordinate to return home and alter her clothing. Upon Thomas Edison's death in 1931, Tesla provided the sole critical assessment published in The New York Times. In his later life, he adopted a vegetarian diet, subsisting exclusively on milk, bread, honey, and vegetable juices.

Views and beliefs

On experimental and theoretical physics

Tesla rejected the prevailing theory positing that atoms comprised smaller subatomic particles, asserting the non-existence of an electron generating an electric charge. His conviction was that, should electrons exist, they constituted a fourth state of matter or "sub-atom" capable of existence solely within an experimental vacuum, and bore no relation to electrical phenomena. Tesla maintained that atoms were immutable entities, incapable of altering their state or undergoing fission. He subscribed to the 19th-century notion of an omnipresent ether responsible for transmitting electrical energy.

Tesla contested the principle of matter-energy equivalence. He expressed strong criticism of Einstein's theory of relativity, remarking, "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." In 1935, he characterized relativity as "a beggar wrapped in purple whom ignorant people take for a king" and asserted that his own experimental work had determined the speed of cosmic rays from Antares to be fifty times the speed of light. Tesla purported to have formulated a distinct physical principle concerning matter and energy, initiating this work in 1892. In 1937, at the age of 81, he asserted in a letter that he had finalized a "dynamic theory of gravity" which "[would] put an end to idle speculations and false conceptions, as that of curved space." He declared the theory to be "worked out in all details" and expressed an aspiration to present it to the global scientific community imminently. No further elaboration of this theory was subsequently discovered within his collected works.

On society

Tesla is generally regarded by his biographers as possessing a humanist philosophical perspective. He articulated the conviction that human "pity" had begun to impede the inherent "ruthless workings of nature." Despite his arguments not relying on notions of a "master race" or the intrinsic superiority of individuals, he nonetheless endorsed eugenics. In 1926, Tesla addressed the detrimental aspects of women's social subservience and their pursuit of gender equality. He suggested that the future of humanity would be governed by "Queen Bees," positing that women would achieve sexual dominance in the future. He offered prognostications concerning pertinent issues of the post-World War I era in an article titled "Science and Discovery are the great Forces which will lead to the Consummation of the War," published on December 20, 1914.

On religion

Nikola Tesla was raised within the Eastern Orthodox Church. However, in his later years, he disavowed being a "believer in the orthodox sense," expressing opposition to religious fanaticism. He posited that "Buddhism and Christianity are the greatest religions both in number of disciples and in importance." Furthermore, Tesla articulated a mechanistic view of existence, stating, "To me, the universe is simply a great machine which never came into being and never will end," and defined the "soul" or "spirit" as merely "the sum of the functionings of the body," ceasing upon the cessation of bodily functions.

Literary Works

Tesla authored numerous books and contributed articles to various magazines and journals. Notable among his published works are My Inventions: The Autobiography of Nikola Tesla, a compilation and editing by Ben Johnston in 1983 derived from a 1919 series of magazine articles by Tesla, which were subsequently republished in 1977; The Fantastic Inventions of Nikola Tesla (1993), compiled and edited by David Hatcher Childress; and The Tesla Papers. A significant portion of his writings is accessible online, including "The Problem of Increasing Human Energy," which appeared in The Century Magazine in 1900, and "Experiments with Alternate Currents of High Potential and High Frequency," featured in his book Inventions, Researches and Writings of Nikola Tesla.

Legacy

In 1952, under the influence of Sava Kosanović, Tesla's complete estate, comprising 80 trunks labeled "N.T.", was transferred to Belgrade. Five years later, in 1957, Charlotte Muzar, Kosanović's secretary, facilitated the relocation of Tesla's ashes from the United States to Belgrade, where they are now exhibited within a gold-plated sphere atop a marble pedestal at the Nikola Tesla Museum. His extensive archive, containing more than 160,000 documents, has been recognized and included in the UNESCO Memory of the World Programme.

Tesla secured approximately 300 patents globally for his various inventions. A number of these patents remain unaccounted for, while others, previously obscured within patent archives, have since been rediscovered. Currently, a minimum of 278 patents issued to Tesla across 26 countries are officially recognized. While a significant proportion originated in the United States, Britain, and Canada, numerous others received approval in diverse nations worldwide.

• Atmospheric electricity – Electricity in planetary atmospheres
• Charles Proteus Steinmetz – American mathematician and electrical engineer (1865–1923)
• Notes

Notes

Footnotes

Citations

References

Books

Journals

• Tesla memorial society by his grand-nephew William H. Terbo
• FBI. "Nikola Tesla" (PDF). Main Investigative File. FBI.
• "Tesla's pigeon" – Amanda Gefter