   #copyright

Thomas Edison

2007 Schools Wikipedia Selection. Related subjects: Engineers and inventors

   CAPTION: 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
   Enlarge
   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)
   Enlarge
   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.
   Enlarge
   Thomas Edison's first light bulb used to demonstrate his invention at
   Menlo Park.
   U.S. Patent #223898 Electric Lamp
   Enlarge
   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.
   Enlarge
   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.
   Enlarge
   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.

Criticism

   Seminole Lodge
   Enlarge
   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.

Tributes

   Statue of Thomas Edison in Dearborn, Michigan.
   Enlarge
   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.

Trivia

   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

Biographies

     * "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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