The American inventor Thomas Alva Edison (1847-1931) held hundreds of patents, most for electrical devices and electric light and power. Although the phonograph and incandescent lamp are best known, perhaps his greatest invention was organized research.
Thomas Edison was born in Milan, Ohio, on Feb. 11, 1847; his father was a jack-of-all-trades, his mother a former teacher. Edison spent 3 months in school, then was taught by his mother. At the age of 12 he sold fruit, candy, and papers on the Grand Trunk Railroad. In 1862, using his small handpress in a baggage car, he wrote and printed the Grand Trunk Herald, which was circulated to 400 railroad employees. That year he became a telegraph operator, taught by the father of a child whose life Edison had saved. Exempt from military service because of deafness, he was a tramp telegrapher until he joined Western Union Telegraph Company in Boston in 1868.
Probably Edison's first invention was an automatic telegraph repeater (1864). His first patent was for an electric vote recorder. In 1869, as a partner in a New York electrical firm, he perfected the stock ticker and sold it. This money, in addition to that from his share of the partnership, provided funds for his own factory in Newark, N.J. Edison hired technicians to collaborate on inventions; he wanted an "invention factory." As many as 80 "earnest men," including chemists, physicists, and mathematicians, were on his staff. "Invention to order" became very profitable.
From 1870 to 1875 Edison invented many telegraphic improvements: transmitters; receivers; the duplex, quadruplex, and sextuplex systems; and automatic printers and tape. He worked with Christopher Sholes, "father of the typewriter," in 1871 to improve the typing machine. Edison claimed he made 12 typewriters at Newark about 1870. The Remington Company bought his interests.
In 1876 Edison's carbon telegraph transmitter for Western Union marked a real advance toward making the Bell telephone practical. (Later, Émile Berliner's transmitter was granted patent priority by the courts.) With the money Edison received from Western Union for his transmitter, he established a factory in Menlo Park, N.J. Again he pooled scientific talent, and within 6 years he had more than 300 patents. The electric pen (1877) produced stencils to make copies. (The A. B. Dick Company licensed Edison's patent and manufactured the mimeograph machine.)
Edison's most original and lucrative invention, the phonograph, was patented in 1877. From a manually operated instrument making impressions on metal foil and replaying sounds, it became a motor-driven machine playing cylindrical wax records by 1887. By 1890 he had more than 80 patents on it. The Victor Company developed from his patents. (Alexander Graham Bell impressed sound tracks on cylindrical shellac records; Berliner invented disk records. Edison's later dictating machine, the Ediphone, used disks.)
To research incandescence, Edison and others, including J. P. Morgan, organized the Edison Electric Light Company in 1878. (Later it became the General Electric Company.) Edison made the first practical incandescent lamp in 1879, and it was patented the following year. After months of testing metal filaments, Edison and his staff examined 6,000 organic fibers from around the world and decided that Japanese bamboo was best. Mass production soon made the lamps, although low-priced, profitable.
Prior to Edison's central power station, each user of electricity needed a dynamo (generator), which was inconvenient and expensive. Edison opened the first commercial electric station in London in 1882; in September the Pearl Street Station in New York City marked the beginning of America's electrical age. Within 4 months the station was lighting more than 5,000 lamps for 230 customers, and the demand for lamps exceeded supply. By 1890 it supplied current to 20,000 lamps, mainly in office buildings, and to motors, fans, printing presses, and heating appliances. Many towns and cities installed central stations.
Increased use of electricity led to Edison-base sockets, junction boxes, safety fuses, underground conduits, meters, and the three-wire system. Jumbo dynamos, with drum-wound armatures, could maintain 110 volts with 90 percent efficiency. The three-wire system, first installed in Sunbury, Pa., in 1883, superseded the parallel circuit, used 110 volts, and necessitated high-resistance lamp filaments (metal alloys were later used).
In 1883 Edison made a significant discovery in pure science, the Edison effect—electrons flowed from incandescent filaments. With a metal-plate insert, the lamp could serve as a valve, admitting only negative electricity. Although "etheric force" had been recognized in 1875 and the Edison effect was patented in 1883, the phenomenon was little known outside the Edison laboratory. (At this time existence of electrons was not generally accepted.) This "force" underlies radio broadcasting, long-distance telephony, sound pictures, television, electric eyes, x-rays, high-frequency surgery, and electronic musical instruments. In 1885 Edison patented a method to transmit telegraphic "aerial" signals, which worked over short distances, and later sold this "wireless" patent to Guglielmo Marconi.
The vast West Orange, N.J., factory, which Edison directed from 1887 to 1931, was the world's most complete research laboratory, an antecedent of modern research and development laboratories, with teams of workers systematically investigating problems. Various inventions included a method to make plate glass, a magnetic ore separator, compressing dies, composition brick, a cement process, an all-concrete house, an electric locomotive (patented 1893), a fluoroscope, a nickel-iron battery, and motion pictures. Edison refused to patent the fluoroscope, so that doctors could use it freely; but he patented the first fluorescent lamp in 1896.
The Edison battery, finally perfected in 1910, was a superior storage battery with an alkaline electrolyte. After 8000 trials Edison remarked, "Well, at least we know 8000 things that don't work." In 1902 he improved the copper oxide battery, which resembled modern dry cells.
Edison's motion picture camera, the kinetograph, could photograph action on 50-foot strips of film, 16 images per foot. A young assistant, in order to make the first Edison movies, in 1893 built a small laboratory called the "Black Maria,"—a shed, painted black inside and out, that revolved on a base to follow the sun and kept the actors illuminated. The kinetoscope projector of 1893 showed the films. The first commercial movie theater, a peepshow, opened in New York in 1884. A coin put into a slot activated the kinetoscope inside the box. Acquiring and improving the projector of Thomas Armat in 1895, Edison marketed it as the Vitascope.
The Edison Company produced over 1,700 movies. Synchronizing movies with the phonograph in 1904, Edison laid the basis for talking pictures. In 1908 his cinemaphone appeared, adjusting film speed to phonograph speed. In 1913 his kinetophone projected talking pictures: the phonograph, behind the screen, was synchronized by ropes and pulleys with the projector. Edison produced several "talkies."
Meanwhile, among other inventions, the universal motor, which used alternating or direct current, appeared in 1907; and the electric safety lantern, patented in 1914, greatly reduced casualties among miners. That year Edison invented the telescribe, which combined features of the telephone and dictating phonograph.
During World War I Edison headed the U.S. Navy Consulting Board and contributed 45 inventions, including substitutes for previously imported chemicals (especially carbolic acid, or phenol), defensive instruments against U-boats, a ship-telephone system, an underwater searchlight, smoke screen machines, antitorpedo nets, turbine projectile heads, collision mats, navigating equipment, and methods of aiming and firing naval guns. After the war he established the Naval Research Laboratory, the only American institution for organized weapons research until World War II.
With Henry Ford and the Firestone Company, Edison organized the Edison Botanic Research Company in 1927 to discover or develop a domestic source of rubber. Some 17,000 different botanical specimens were examined over 4 years—an indication of Edison's tenaciousness. By crossbreeding goldenrod, he developed a strain yielding 12 percent latex, and in 1930 he received his last patent, for this process.
To raise money, Edison dramatized himself by careless dress, clowning for reporters, and playing the role of homespun sage with aphorisms like "Genius is 1 percent inspiration and 99 percent perspiration" and "Discovery is not invention." He scoffed at formal education, thought 4 hours' sleep a night enough, and often worked 40 or 50 hours straight. As a world symbol of Yankee ingenuity, he looked and acted the part. George Bernard Shaw, briefly an Edison employee in 1879, put an Edisontype hero into his novel The Irrational Knot: free-souled, sensitive, cheerful, and profane.
Edison had more than 10,000 books at home and masses of printed materials at the laboratory. When launching a new project, he wished to avoid others' mistakes and to know everything about a subject. Some 25,000 notebooks contained his research records, ideas, hunches, and mistakes. Supposedly, his great shortcoming was lack of interest in anything not utilitarian; yet he loved to read Shakespeare and Thomas Paine.
Edison died in West Orange, N.J., on Oct. 18, 1931. The laboratory buildings and equipment associated with his career are preserved in Greenfield Village, Detroit, Mich., thanks to Henry Ford's interest and friendship.
A good biography of Edison, filled with human interest, is Matthew Josephson, Edison: A Biography (1959). Biographies emphasizing his inventions include William Adams Simonds, Edison: His Life, His Work, His Genius (1934), and H. Gordon Garbedian, Thomas Alva Edison: Builder of Civilization (1947). There is more emphasis on industry in John Winthrop Hammond, Men and Volts: The Story of General Electric, edited by Arthur Pound (1941). See also Charles Singer and others, eds., A History of Technology, vol.5: The Late Nineteenth Century (1958). □