Thomas Edison

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Thomas Alva Edison

"Genius is one percent inspiration, ninety-nine percent perspiration." - Thomas Edison, Harper's Monthly (September 1932)
Born: February 11, 1847
Milan, Ohio, United States
Died: October 18, 1931
West Orange, New Jersey, United States
Occupation: Inventor, entrepreneur
Spouse: Mary Edison, Mina Edison

Thomas Alva Edison ( February 11, 1847 – October 18, 1931) was an American inventor and businessman who developed many devices which greatly influenced life in the 20th century. Dubbed "The Wizard of Menlo Park" by a newspaper reporter, he was one of the first inventors to apply the principles of mass production to the process of invention, and can therefore be credited with the creation of the first industrial research laboratory. Some of the inventions attributed to him were not completely original but amounted to improvements of earlier inventions or were actually created by numerous employees working under his direction. Nevertheless, Edison is considered one of the most prolific inventors in history, holding 1,097 U.S. patents in his name, as well as many patents in the United Kingdom, France, and Germany.

Early life

Thomas Edison was born in Milan, Ohio, the seventh child of Samuel Ogden Edison, Jr. (1804–1896) (born in Marshalltown, Nova Scotia, Canada) and the former Nancy Matthews Elliott (1810–1871). His family was of Dutch origin. His mind often wandered and his teacher the Reverend Engle was overheard calling him "addled". This ended Edison's three months of formal schooling. His mother had been a school teacher in Canada and happily took over the job of schooling her son. She encouraged and taught him to read and experiment. He recalled later, "My mother was the making of me. She was so true, so sure of me; and I felt I had something to live for, someone I must not disappoint." Many of his lessons came from reading R.G. Parker's School of Natural Philosophy. Edison became hard of hearing at the age of twelve. There are many theories of what caused this; according to Edison he went deaf because he was pulled up to a train car by his ears.

Edison's life in Port Huron, Michigan was bittersweet. He sold candy and newspapers on trains running from Port Huron to Detroit. Partially deaf since adolescence, he became a telegraph operator after he saved Jimmie Mackenzie from being struck by a runaway train. Jimmie's father, station agent J.U. Mackenzie of Mount Clemens, Michigan, was so grateful that he took Edison under his wing and trained him as a telegraph operator. Edison's deafness aided him as it blocked out noises and prevented Edison from hearing the telegrapher sitting next to him. One of his mentors during those early years was a fellow telegrapher and inventor named Franklin Leonard Pope, who allowed the then impoverished youth to live and work in the basement of his Elizabeth, New Jersey home.

Some of his earliest inventions related to electrical telegraphy, including a stock ticker. Edison applied for his first patent, the electric vote recorder, on October 28, 1868.

Marriages and children

On December 25, 1871, Edison married the then 16 year old Mary Stilwell whom he had met two months earlier. They had three children,

  • Marion "Dot" Estelle Edison ( 1873– 1965)
  • Thomas "Dash" Alva Edison, Jr ( 1876– 1935)
  • William Leslie Edison ( 1878– 1935)

Mary Edison died on August 9 1884.

On February 24, 1886, at the age of thirty-nine, Edison married 19-year-old Mina Miller in Akron, Ohio. They also had three children:

  • Madeleine Edison ( 1888– 1979)
  • Charles Edison ( 1890– 1969), who took over the company upon his father's death and who later was elected Governor of New Jersey)
  • Theodore Edison ( 1898– 1992)

Mina outlived Thomas Edison, dying on August 24, 1947.

Beginning his career

Edison and early phonograph, 1877
Edison and early phonograph, 1877

Thomas Edison began his career as an inventor in Newark, New Jersey, with the automatic repeater and his other improved telegraphic devices, but the invention which first gained him fame was the phonograph in 1877. This accomplishment was so unexpected by the public at large as to appear almost magical. Edison became known as "The Wizard of Menlo Park," New Jersey, where he lived. His first phonograph recorded on tinfoil cylinders that had low sound quality and destroyed the track during replay so that one could listen only a few times. In the 1880s, a redesigned model using wax-coated cardboard cylinders was produced by Alexander Graham Bell, Chichester Bell, and Charles Tainter. This was one reason that Thomas Edison continued work on his own "Perfected Phonograph."

Thomas Edison was a freethinker, and was most likely a deist, claiming he did not believe in "the God of the theologians", but did not doubt that "there is a Supreme Intelligence". He is quoted, "I believe that the science of chemistry alone almost proves the existence of an intelligent creator." However, he rejected the idea of the supernatural, along with such ideas as the soul, immortality, and a personal God. "Nature", he said, "is not merciful and loving, but wholly merciless, indifferent."

Menlo Park

Edison's Menlo Park Laboratory, removed to Greenfield Village in Dearborn, MI.  (Note the organ against the back wall)
Edison's Menlo Park Laboratory, removed to Greenfield Village in Dearborn, MI. (Note the organ against the back wall)
Thomas Edison's first light bulb used to demonstrate his invention at Menlo Park.
Thomas Edison's first light bulb used to demonstrate his invention at Menlo Park.
U.S. Patent #223898 Electric Lamp
U.S. Patent #223898 Electric Lamp

Edison's major innovation was the first industrial research lab, which was built in Menlo Park, New Jersey. It was the first institution set up with the specific purpose of producing constant technological innovation and improvement. Edison was legally attributed with most of the inventions produced there, though many employees carried out research and development work under his direction.

William Joseph Hammer, a consulting electrical engineer, began his duties as a laboratory assistant to Edison in December 1879. He assisted in experiments on the telephone, phonograph, electric railway, iron ore separator, electric lighting, and other developing inventions. However, Hammer worked primarily on the incandescent electric lamp and was put in charge of tests and records on that device. In 1880 he was appointed Chief Engineer of the Edison Lamp Works. In his first year, the plant under general manager Francis Robbins Upton turned out 50,000 lamps. According to Edison, Hammer was "a pioneer of incandescent electric lighting."

Most of Edison's patents were utility patents, which during Edison's lifetime protected for a 17-year period inventions or processes that are electrical, mechanical, or chemical in nature. About a dozen were design patents, which protect an ornamental design for a 14 year period. Like most inventions, his were not typically completely original, but improvements to prior art. The phonograph patent, on the other hand, was unprecedented as the first device to record and reproduce sounds. Edison did not invent the first electric light bulb, but instead invented the first commercially practical incandescent light. Several designs had already been developed by earlier inventors including the patent he purchased from Henry Woodward and Mathew Evans, Moses G. Farmer, Joseph Swan, James Bowman Lindsay, William Sawyer, Sir Humphry Davy, and Heinrich Göbel. Some of these early bulbs had such flaws as extremely short life, high expense to produce, and high current draw, making them difficult to apply on a large scale commercially. In 1878, Edison applied the term filament to the element of glowing wire carrying the current, although English inventor Joseph Swan had used the term prior to this. Edison took the features of these earlier designs and set his workers to the task of creating longer-lasting bulbs. By 1879, he had produced a new concept: a high resistance lamp in a very high vacuum, which would burn for hundreds of hours. While the earlier inventors had produced electric lighting in laboratory conditions dating back to a demonstration of a glowing wire by Alessandro Volta in 1800, Edison concentrated on commercial application and was able to sell the concept to homes and businesses by mass-producing relatively long-lasting light bulbs and creating a complete system for the generation and distribution of electricity.

The Menlo Park research lab was made possible by the sale of the quadruplex telegraph that Edison invented in 1874, which could send four simultaneous telegraph signals over the same wire. When Edison asked Western Union to make an offer, he was shocked at the unexpectedly large amount that Western Union offered; the patent rights were sold for $10,000. The quadruplex telegraph was Edison's first big financial success.

Incandescent era

In 1878, Edison formed the Edison Electric Light Company in New York City with several financiers, including J. P. Morgan and the Vanderbilt families. Edison made the first public demonstration of his incandescent light bulb on December 31, 1879, in Menlo Park. On January 27, 1880, he filed a patent in the United States for the electric incandescent lamp; it was during this time that he said, "We will make electricity so cheap that only the rich will burn candles."

On October 8, 1883, the U.S. patent office ruled that Edison's patent was based on the work of William Sawyer and was therefore invalid. Litigation continued for nearly six years, until October 6, 1889, when a judge ruled that Edison's electric light improvement claim for "a filament of carbon of high resistance" was valid. To avoid a possible court battle with Joseph Swan, whose English patent had been awarded a year before Edison's, he and Swan formed a joint company called Ediswan to market the invention in Britain.

Other designs for a light bulb included Serbian inventor Nikola Tesla's idea of utilizing radio frequency waves emitted (in the Tesla effect) from the side electrode plates to light a wireless bulb. He also developed plans to light a bulb with only one wire with the energy refocused back into the center of the bulb by the glass envelope with a centre "button" to emit an incandescent glow. Edison's design won out during this time, although Tesla did go on to invent fluorescent lighting.

Edison patented an electric distribution system in 1880, which was critical to capitalize on the invention of the electric lamp. The first investor-owned electric utility was the 1882 Pearl Street Station, New York City. On September 4, 1882, Edison switched on the world's first electrical power distribution system, providing 110 volts direct current (DC) to 59 customers in lower Manhattan, around his Pearl Street generating station. On January 19, 1883, the first standardized incandescent electric lighting system employing overhead wires began service in Roselle, New Jersey.

  • Edison speech on light bulb
    • Video clip of Thomas Edison talking about the invention of the light bulb, late 1920s.
  • .

Carbon telephone transmitter

In 1877 and 1878 Edison invented and developed the carbon microphone used in all telephones along with the Bell receiver until the 1980s. After protracted patent litigation, a federal court ruled in 1892 that Edison and not Emile Berliner was the inventor of the carbon microphone. (Josephson, p146). The carbon microphone was also used in radio broadcasting and public address work through the 1920s.

War of currents

Extravagant displays of electric lights quickly became a feature of public events, as this picture from the 1897 Tennessee Centennial Exposition shows.
Extravagant displays of electric lights quickly became a feature of public events, as this picture from the 1897 Tennessee Centennial Exposition shows.

George Westinghouse and Edison became adversaries due to Edison's promotion of direct current (DC) for electric power distribution over the more easily transmitted alternating current (AC) system promoted by George Westinghouse. Unlike DC, AC could be stepped up to very high voltages with transformers, sent over thinner and less expensive wires, and stepped down again at the destination for distribution to users.

Despite Edison's contempt for capital punishment, the war against AC led Edison to become involved in the development and promotion of the electric chair as a demonstration of AC's greater lethal potential versus the "safer" DC. Edison went on to carry out a brief but intense campaign to ban the use of AC or to limit the allowable voltage for safety purposes. As part of this campaign, Edison's employees publicly electrocuted dogs, cats, and in one case, an elephant to demonstrate the dangers of AC. AC replaced DC in most instances of generation and power distribution, enormously extending the range and improving the efficiency of power distribution. Though widespread use of DC ultimately lost favour for distribution, it exists today primarily in long-distance high-voltage direct current (HVDC) transmission systems. Low voltage DC distribution continued to be used in high density downtown areas for many years and was replaced by AC low voltage network distribution in many central business districts. DC had the advantage that large battery banks could maintain continuous power through brief interruptions of the electric supply from generators and the transmission system. Utilities such as Commonwealth Edison in Chicago had rotary converters which could change DC to AC and AC to various frequencies in the early to mid 20th century. Utilities supplied rectifiers to convert the low voltage AC to DC for such DC load as elevators, fans and pumps. There were still 1600 DC customers in downtown New York City when the service was discontinued in 2005.

Work relations

Frank J. Sprague, a competent mathematician and former naval officer, was recruited by Edward H. Johnson, and joined the Edison organization in 1883. One of Sprague's significant contributions to the Edison Laboratory at Menlo Park was to expand Edison's mathematical methods. (Despite the common belief that Edison did not use mathematics, analysis of his notebooks reveal that he was an astute user of mathematical analysis, for example, determining the critical parameters of his electric lighting system including lamp resistance by a sophisticated analysis of Ohm's Law, Joule's Law and economics.) A key to Edison's success was a holistic rather than reductionist approach to invention, making extensive use of trial and error when no suitable theory existed. (See Edisonian approach). Since Sprague joined Edison in 1883 and Edison's output of patents peaked in 1880 it could be interpreted that the shift towards a reductionist analytical approach may not have been a positive move for Edison. Sprague's important analytical contributions, including correcting Edison's system of mains and feeders for central station distribution, form a counter argument to this. In 1884, Sprague decided his interests in the exploitation of electricity lay elsewhere, and he left Edison to found the Sprague Electric Railway & Motor Company. However, Sprague, who later developed many electrical innovations, always credited Edison for their work together.

Another of Edison's assistants was Nikola Tesla who claimed that Edison promised him $50,000 if he succeeded in making improvements to his DC generation plants. Several months later, when he had finished the work and asked to be paid, Tesla claimed that Edison said, "When you become a full-fledged American you will appreciate an American joke". Tesla immediately resigned. This anecdote is somewhat doubtful, since at Tesla's salary of $18 per week the bonus would have amounted to over 53 years pay, and the amount was equal to the initial capital of the company. Tesla resigned when he was refused a raise to $25 per week (Jonnes, p110). Although Tesla accepted an Edison Medal later in life and professed a high opinion of Edison as an inventor and engineer, he remained bitter. The day after Edison died the New York Times contained extensive coverage of Edison's life, with the only negative opinion coming from Tesla who was quoted as saying, "He had no hobby, cared for no sort of amusement of any kind and lived in utter disregard of the most elementary rules of hygiene" and that, "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." When Edison was a very old man and close to death, he said, in looking back, that the biggest mistake he had made was that he never respected Tesla or his work.

Later years

Edison celebrates his 82nd birthday with President Herbert Hoover, Henry Ford, and Harvey Firestone. Ft. Myers, Florida, February 11, 1929.
Edison celebrates his 82nd birthday with President Herbert Hoover, Henry Ford, and Harvey Firestone. Ft. Myers, Florida, February 11, 1929.

Edison became the owner of his Milan, Ohio, birthplace in 1906, and, on his last visit, in 1923, he was shocked to find his old home still lit by lamps and candles. Influenced by a fad diet that was popular in the day, in his last few years "he consumed nothing more than a pint of milk every three hours". He believed this diet would restore his health.

Edison was active in business right up to the end. Just months before his death in 1931, the Lackawanna Railroad implemented electric trains in suburban service from Hoboken to Gladstone, Montclair and Dover in New Jersey. Transmission was by means of an overhead catenary system, with the entire project under the guidance of Thomas Edison. To the surprise of many, Thomas Edison was at the throttle of the very first MU (Multiple-Unit) train to depart Lackawanna Terminal in Hoboken, driving the train all the way to Dover. As another tribute to his lasting legacy, the very same fleet of cars Edison deployed on the Lackawanna in 1931 served commuters until their retirement in 1984. A special plaque commemorating the joint achievement of both the railway and Edison, can be seen today in the waiting room of Lackawanna Terminal in Hoboken, presently operated by New Jersey Transit.

Edison purchased a home known as "Glenmont" in 1886 as a wedding gift for Mina in Llewellyn Park in West Orange, New Jersey. The remains of Edison and his wife, Mina, are now buried there. The 13.5 acre (55,000 m²) property is maintained by the National Park Service as the Edison National Historic Site. Thomas Edison died on October 18, 1931, in New Jersey at the age of 84. His final words to his wife were "It is very beautiful over there." Mina died in 1947. Edison's last breath is purportedly contained in a test tube at the Henry Ford Museum. Ford reportedly convinced Charles Edison to seal a test tube of air in the inventor's room shortly after his death, as a memento. A plaster death mask was also made.

In the 1880s, Thomas Edison bought property in Fort Myers, Florida, and built Seminole Lodge as a winter retreat. Henry Ford, the automobile magnate, later lived a few hundred feet away from Edison at his winter retreat, The Mangoes. Edison even contributed technology to the automobile. They were friends until Edison's death.


Seminole Lodge
Seminole Lodge

Although in his early years Edison worked alone, he built up a research and development team to a considerable number while at his Menlo Park research laboratory. This large research group, which included engineers and other workers, often based their research on work done by others before them, as is true of all research and development. Many have claimed that when his staff succeeded, he presented the inventions as his own and got the credit for them as they were patented in his name. His staff generally carried out his directions in conducting research, and when he was absent from the lab, the pace of work slowed greatly. Other inventors had worked on the development of an incandescent light bulb before Edison invented the first which was commercially practical. He is commonly credited as its inventor, even though a number of employees also worked on the device under his direction. His was the first incandescent light bulb with high resistance, a small radiating area, and a commercially useful lifetime. Other critics have claimed that he put obstacles in the way of his competitors, and used other methods which were ethically questionable, even if their technology was superior to what was created by his own workers.

Thomas Edison made an electric light bulb and said that in six weeks, he would have a light bulb industry and would be generating electricity from Niagara Falls. Investors, including JP Morgan, invested large amounts of money in Edison's scheme. The breakthrough came in the fourteenth month when they finally found material suitable for use as a filament. They put lights around Menlo Park and lots of people came to see them. After two years, there was a prototype lighting system at his complex. The people working at Menlo Park couldn't create enough light bulbs, so he wanted to mass produce them, however the investors didn't want to spend any more money until the original promise was met. Four years after the original promise, the lights turned on at Central Station. Some other towns then began to install lights. Soon after that, competitors emerged, including George Westinghouse.

Edison launched a propaganda campaign to convince people that AC was too dangerous. He repeatedly electrocuted animals with 1000V of alternating current to 'prove' that AC was unsafe. Thomas Edison introduced execution by electrocution. In 1889, a murderer ( William Kemmler) was executed by electrocution. The executioners left the current on for 17 seconds. He was smoking, so it was turned off, but he wasn't dead; he was bleeding out of multiple places and was having spasms, so they quickly turned it back on and left it on for 72 seconds. His body was smouldering. After this, the public outrage was so strong that he was fired from his company, it was renamed "General Electric" and it joined with George Westinghouse. Finally, the company built the hydro-electric plant at Niagra Falls.

One of the more notable occasions when Edison electrocuted animals was when in 1903, he electrocuted Topsy the elephant at Luna Park. Edison claimed that it was the AC power's fault that the animals died; not his. He claimed that the animals being electrocuted were being "Westinghoused". Edison even filmed the death of Topsy and gladly distributed the video.


Statue of Thomas Edison in Dearborn, Michigan.
Statue of Thomas Edison in Dearborn, Michigan.

As a famous inventor, many tributes have been made to Thomas Edison. Several places and objects have been named after the inventor, including the town of Edison, New Jersey, and Thomas Edison State College, a nationally-known college for adult learners in Trenton, New Jersey. There is a Thomas Alva Edison Memorial Tower and Museum in the town of Edison. In the Netherlands, major music awards are named after him. The City Hotel, in Sunbury, Pennsylvania, was the first building to be lit with Edison's three-wire system. The hotel was renamed The Hotel Edison, and retains that name today. The "Incredible Machines: Contraptions" game series has an alligator The United States Navy named the USS Edison, a Gleaves class destroyer, in his honour in 1940. The ship was decommissioned a few months after the end of World War II. In 1962, the Navy commissioned USS Thomas A. Edison, a fleet ballistic missile nuclear-powered submarine. Decommissioned on 1 December 1983, Thomas A. Edison was stricken from the Naval Vessel Register on April 30, 1986. She went through the Navy’s Nuclear Powered Ship and Submarine Recycling Program at Bremerton, Washington, beginning on 1 October 1996. When she finished the program on December 1, 1997, she ceased to exist as a complete ship and was listed as scrapped.

The Edison Medal was created on February 11, 1904, by a group of Edison's friends and associates. Four years later the American Institute of Electrical Engineers (AIEE), later IEEE, entered into an agreement with the group to present the medal as its highest award. The first medal was presented in 1909 to Elihu Thomson, and ironically, was awarded to Nikola Tesla in 1917. The Edison Medal is the oldest award in the area of electrical and electronics engineering, and is presented annually "for a career of meritorious achievement in electrical science, electrical engineering or the electrical arts."

Several landmarks exist in honour of Edison. The Port Huron Museums, in Port Huron, Michigan, restored the original depot that Thomas Edison worked out of as a young newsbutcher. The depot has appropriately been named the Thomas Edison Depot Museum. The town has many Edison historical landmarks including the gravesites of Edison's parents.

In Detroit, the Edison Memorial Fountain in Grand Circus Park was created to honour his achievements. The limestone fountain was dedicated October 21, 1929.

Life magazine (USA), in a special double issue, placed Edison first in the list of the "100 Most Important People in the Last 1000 Years", noting that his light bulb "lit up the world". He was ranked thirty-fifth on Michael H. Hart's list of the most influential figures in history. In 1940, his life was documented on the screen when Spencer Tracy starred as Edison in "Edison The Man." He has been called the fifteenth Greatest American.

In recognition of the enormous contribution inventors make to the nation and the world, the Congress, pursuant to Senate Joint Resolution 140 (Public Law 97 - 198), has designated February 11, the anniversary of the birth of Thomas Alva Edison, as National Inventor's Day.

In 1879, Auguste Villiers de l'Isle-Adam wrote the book "L'Ève Future" (translated into English as "Tomorrow's Eve"), about a fictional Thomas Edison who creates the ideal (artificial) woman.


Edison helped found one of the very first Montessori schools in the United States.

Companies bearing Edison's name

  • Edison General Electric, now General Electric
  • Commonwealth Edison, now part of Exelon
  • Consolidated Edison
  • Edison International
    • Southern California Edison
    • Edison Mission Energy
    • Edison Capital
  • Detroit Edison, a unit of DTE Energy
  • Edison Sault Electric Company, a unit of Wisconsin Energy
  • FirstEnergy
    • Metropolitan Edison
    • Ohio Edison
    • Toledo Edison
  • Edison S.p.A., a unit of Italenergia
  • Boston Edison, a unit of NSTAR


  • "A Streak of Luck," by Robert Conot, Seaview Books, New York, 1979, ISBN 0-87223-521-1
  • "Edison: The man who made the future", by Ronald W. Clark, ISBN 0-354-04093-6
  • "Edison" by Matthew Josephson. McGraw Hill, New York, 1959, ISBN 07-033046-8
  • "Edison: Inventing the Century" by Neil Baldwin, University of Chicago Press, 2001, ISBN 0-226-03571-9
  • "Edison: A Life of Invention", by Paul Israel, Wiley, 1998, ISBN 0-471-36270-0
  • "Edison and the Electric Chair" Mark Essig, ISBN 0-7509-3680-0
  • "Working at Inventing: Thomas A. Edison and the Menlo Park Experience," edited by William S. Pretzer, Henry Ford Museum & Greenfield Village, Dearborn, Michigan, 1989, ISBN 00-933728-33-6(cloth) ISBN 00-933728-34-4(paper)
  • Ernst Angel: Edison. Sein Leben und Erfinden. Berlin: Ernst Angel Verlag, 1926.
  • Mark Essig: Edison & the Electric Chair: A Story of Light and Death. New York: Walker & Company, 2003. ISBN 0-8027-1406-4
  • Jill Jonnes, Empires of Light: Edison, Tesla, Westinghouse, and the Race to Electrify the World. New York: Random House, 2003. ISBN 0-375-50739-6

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