Signedon top: DE FOREST RADIO TEL. & TEL. Co., N.Y., USA.
Inscribedon top: U.S. PATENT NOS. 835 010 / 876 868 / 879 532 / 836 071/ 867 878 / 979 275 / AND OTHER PATENTS.
FunctionThis is an early radio set used to amplify radio wave frequencies. It employs an "audion" tube, a type of vacuum tube invented by Lee De Forest in 1906. A New York Times article from December 4, 1916 describes the audion as serving "both to detect or to rectify the incoming waves, and to amplify the resulting currents thousands of times in order to actuate the various types of recording instruments."
Historical AttributesThis is one of the earliest radios employing the Audion vacuum tube. Although Lee de Forest invented the Audion in 1906, he was slow to employ it as a signal amplifier or detector in radio receivers until about 1914. It seems he never fully understood how it worked. That same year, Edwin H. Armstrong, still a Columbia University student, published explanations concerning the physics of the Audion and patented the regenerative radio circuit. Armstrong further solidified his radio engineering credentials with inventions such as the superheterodyne receiver and frequency modulation (FM) radio transmission.
Armstrong made this radio set in 1916 for the son of his Yonkers neighbor and close friend, Thomas Ewing III, a New York patent attorney and Commissioner of the U.S. Patent Office. The twelve-year-old boy who got the radio, Gifford C. Ewing, went on to become the first physical oceanographer to use satellite data.
ProvenanceDavid Wheatland.
Related WorksLee De Forest, Father of Radio: The Autobiography of Lee De Forest (Chicago: Wilcox and Follett, 1950).
Douglas, 1: 162-163.