Thomas Alva Edison (February 11, 1847 – October 18, 1931) was an American inventor and businessman. He developed many devices that greatly influenced life around the world, including the phonograph, the motion picture camera, and a long-lasting, practical electric light bulb. Dubbed “The Wizard of Menlo Park”, he was one of the first inventors to apply the principles of mass production and large-scale teamwork to the process of invention, and because of that, he is often credited with the creation of the first industrial research laboratory.
Edison is the fourth most prolific inventor in history, holding 1,093 US patents in his name, as well as many patents in the United Kingdom, France, and Germany. He is credited with numerous inventions that contributed to mass communication and, in particular, telecommunications. These included a stock ticker, a mechanical vote recorder, a battery for an electric car, electrical power, recorded music and motion pictures.
His advanced work in these fields was an outgrowth of his early career as a telegraph operator. Edison developed a system of electric-power generation and distribution to homes, businesses, and factories – a crucial development in the modern industrialized world. His first power station was on Pearl Street in Manhattan, New York.
Radio pioneer Arthur Edwin Kennelly, the son of an Irish naval officer, was born in Colaba, India (near Bombay), on 17 December 1861. Educated in England and France, he left school at the age of thirteen and taught himself physics while working as a telegrapher. In 1876, he left England and held various positions, including that of an assistant electrician in Malta, chief electrician of a cable repairing steamer, and, finally, senior ship’s electrician. In 1887, he immigrated to the United States and became principal assistant in Thomas Edison’s West Orange, New Jersey lab. Between 1894 and 1901, Kennelly worked as a consulting engineer for the Edison General Electric Company of New York. He then formed the consulting firm of Houston and Kennelly in Philadelphia with Edwin J. Houston. In 1902, the government of Mexico retained his firm to oversee the laying of the Veracruz-Frontera-Campeche cables. Kennelly also had a career in academia—he was a Professor of Electrical Engineering both at Harvard University and the Massachusetts Institute of Technology (MIT) and was a research associate at the Carnegie-Mellon Institute.
In 1901, Kennelly noticed that Guglielmo Marconi’s reception in Newfoundland of radio signals transmitted from England was received far better than predicted by radio-wave theory. Kennelly and the Englishman Oliver Heaviside, independently, and at approximately the same time in 1902, announced the probable existence of a layer of ionized gas high in the atmosphere that reflected radio waves. Formerly called the Heaviside or Kennelly-Heaviside layer (now called the E region), it is one of the several layers of the ionosphere. Although short wavelength radio waves penetrate the ionosphere, longer waves reflect off it instead, a property which allows them to “curve” around the earth and be propagate far beyond the horizon. Kennelly is also known for the contributions he made to the analysis of alternating-current (AC) circuits with the publication of his paper “Impedance.” In that paper he described the first use of complex numbers as applied to Ohm’s Law in AC circuit theory.
Kennelly received many awards during his lifetime. These included the IEE Institution Premium, the Franklin Institute Howard Potts Gold Medal, the Cross of a Chevalier of the Legion d’Honneur of France, and the AIEE Edison Medal (1933). In 1932 he received the IRE Medal of Honor “[f]or his studies of radio propagation phenomena and his contributions to the theory and measurement methods in the alternating current circuit field which now have extensive radio application.” He served as president of the American Institute of Electrical Engineers fron 1898 to 1900 and president of the Institute of Radio Engineers in 1916. Kennelly died in Boston, Massachusetts on 18 June 1939.
Reginald Aubrey Fessenden (October 6, 1866 – July 22, 1932), was a Canadian inventor, born in Quebec, Canada, who performed pioneering experiments in radio, including the use of continuous waves and the early—and possibly the first—radio transmissions of voice and music. In his later career he received hundreds of patents for devices in fields such as high-powered transmitting, sonar, and television.
Fessenden’s classical education provided him with only a limited amount of scientific and technical training. Interested in increasing his skills in the electrical field, he moved to New York City in 1886, with hopes of gaining employment with the famous inventor, Thomas Edison. As recounted in his 1925 Radio News autobiography, his initial attempts were rebuffed; in his first application Fessenden wrote, “Do not know anything about electricity, but can learn pretty quick,” to which Edison replied, “Have enough men now who do not know about electricity.” However, Fessenden persevered, and before the end of the year he was hired for a semi-skilled position as an assistant tester for the Edison Machine Works, which was laying underground electrical mains in New York City. He quickly proved his worth, and received a series of promotions, with increasing responsibility for the project. In late 1886, Fessenden began working directly for Thomas Edison at the inventor’s new laboratory in West Orange, New Jersey. A broad range of projects included work in solving problems in chemistry, metallurgy, and electricity. However, in 1890, facing financial problems, Edison was forced to lay off most of the laboratory employees, including Fessenden.
Taking advantage of his recent practical experience, Fessenden was able to find positions with a series of manufacturing companies. Next, in 1892, he received an appointment as professor for the newly formed Electrical Engineering department at Purdue University in West Lafayette, Indiana; while there he helped the Westinghouse Corporation install the lighting for the 1893 World Columbian Exposition in Chicago. Shortly thereafter in the same year, George Westinghouse personally recruited Fessenden for the newly created position of chair of the Electrical Engineering department at the Western University of Pennsylvania, renamed to the University of Pittsburgh in 1908. Fessenden began experimenting with wireless telephones in 1898; by 1899 he had a wireless communication system functioning between Pittsburgh and Allegheny City.
