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| e. Transportation and Communication |
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| 1920 |
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| Frank Conrad (1874–1941) of the Westinghouse Co. began broadcasting radio programs in Pittsburgh, marking the beginning of radio as a mass communication medium. | 1 |
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| 1922 |
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| Herbert T. Kalmus developed Technicolor, the first commercially successful color process for motion pictures. | 2 |
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| 1926 |
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| Sound Motion Pictures. Although Edison had attempted to put together his phonograph and motion picture inventions for sound movies as early as 1904, it was 1923 before de Forest successfully demonstrated his phonofilm system for recording sound on the motion picture film. The first motion picture with sound accompaniment was publicly shown in 1926, the first talking picture in 1927. | 3 |
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| 1926 Ff |
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| John L. Baird (1888–1946) successfully demonstrated television in England. His mechanical system of television, similar to that of C.F. Jenkins in the U.S., was based on Paul von Nipkov's rotating disk (1886) but had technical limitations; modern electronic television developed from the cathode-ray tube (1897) of Ferdinand Braun and A.A. Campbell-Swinton's proposals (1911) for use of a cathode ray to scan an image. The crucial invention was the Iconoscope of the Russian American Vladimir Zworykin (1889–1982), the device that transmits television images quickly and effectively. Philo Farnsworth of the U.S. contributed the image dissector tube (1927). General broadcasting of television began in England in 1936, in the U.S. in 1941, but languished until after World War II. Peter C. Goldmark of Columbia Broadcasting System (CBS) demonstrated (1940) a sequential method of color television, which gave way to a compatible electronic system developed by RCA in the 1950s. | 4 |
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| 1932 |
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| Edwin H. Land (1909–91) invented the first practical synthetic light-polarizing material (polaroid glass), found useful in sunglasses, cameras, and scientific optical instruments. In 1947 he invented the Polaroid Land camera, which developed the film inside the camera and produced a photograph print within one minute; in 1962 he introduced color film for his camera. | 5 |
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| 1933 |
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| Fluorescent lamps introduced for floodlighting and advertising. Developments leading up to this included experiments by George Stokes (1852) and Alexandre Becquerel (1859) to excite fluorescent materials by ultraviolet rays or in a discharge tube; Peter Cooper-Hewitt's invention of the mercury vapor lamp (1901); the introduction of the Neon lamp by Georges Claude and the work on cathodes by D.M. Moore and Wehnelt in the 1900s; and J. Risler's application of powder to the outside of tubular discharge lamps (1923). Subsequent developments have included increased cathode life and improved fluorescent powders. | 6 |
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| 1933 |
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| Edwin H. Armstrong (1890–1954), pioneer radio inventor (regenerative, that is, feedback, circuit, 1912, and superheterodyne circuit, 1918), perfected frequency modulation (FM), providing static-free radio reception. | 7 |
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| 1937 |
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| Chester Carlson patented a new dry photographic process (Xerography) based upon principles of photoconductivity and electrostatics. | 8 |
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| 1939 |
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| Igor Sikorsky (1889–1972) flew the first helicopter of his design. The first helicopter capable of flight was the work of Ellehammer of Denmark (1912), based on C. Renard's articulated rotor blade (1904) and G. A. Crocco's cyclic pitch control (1906). Juan de la Cierva invented the autogiro (1922), differing from the helicopter in that its rotor autorotated and the engine drove a normal propeller. Further development work was done (1934–36) by Louis Breguet and Heinrich Focke. | 9 |
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| 1939 |
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| First test flight of a turbo-jet airplane (Heinkel) with an engine designed by Hans von Ohain. Simultaneous and parallel work on jet airplanes in Britain, based on turbo-jet engine designed by Frank Whittle (1930). In 1958 jet-powered transatlantic airline service was inaugurated by BOAC and Pan-American Airways. In 1962 the British and French governments announced plans to cooperate on the production of a jet-propelled supersonic transport plane (the Concorde), and the U.S. government proposed American production of a supersonic commercial plane the following year. The first plane to exceed the speed of sound in level flight was the American rocket-propelled Bell X-1, which reached Mach 1.06 (approximately 750 m.p.h.) on October 14, 1947. | 10 |
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| 1940–45 |
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| Development of radar (“radio-detection-and-ranging”) stimulated by World War II, for detection of aircraft, blind-bombing techniques, and naval search equipment. Based on Heinrich Hertz's demonstration (1887) that radio waves are reflected similarly to light rays, the technique was first applied by Edward Appleton in Britain (1924) and G. Breit and M. A. Tuve in the U.S. (1925) for investigating ionization in the upper atmosphere. Robert A. Watson-Watt showed the possibilities of employing radio waves to detect aircraft (1935); J.T. Randall and H.A.H. Boot developed the cavity magnetron for high-power microwave transmission. Simultaneously, radar development had been going on in Germany and the U.S., including the development of equipment by Robert H. Page of the Naval Laboratory. After 1940 Britain and the U.S. cooperated in radar development, much of the work being done at the Radiation Laboratory in Cambridge, Mass. | 11 |
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