Development Of Communications - From Telegraph To T.V.

Old western stagecoach, Image of a rotating world globe in the sky with lighting flash. Still image of Alessandro Volta, Italian physicist known for the invention of the DC (direct current) battery. Still image of William Watson English physician and scientist. Animation used to illustrate the flow of DC current using the earth to complete the circuit. Still image of Joseph Henry an American scientist. Still image of Samuel Morse American inventor. Animation illustrates how the telegraph works. Image of original model of the world's first telegraph. Image of a hand operating a telegraph keyboard sending a telegraph message. Shows laying of telegraph wires cable between North America and Europe in 1866. In 1876 Alexander Graham Bell discovered the principal of the telephone. Animation illustrates the principal of the telephone, brief image of telephone switchboard and telephone poles and wires along a rural road. Still image of Guglielmo Marconi Italian engineer and inventor known for his pioneering work on long-distance wireless communications. Animation is used to illustrate the operation of a vacuum tube. A radio announcer says "this is station KDKA, Pittsburgh, bringing you a program of news and music". An animated image depicts radio station KDKA in Pittsburgh Pennsylvania, the first licensed October 1920 commercial broadcasting station in the United States. The invention of the vacuum tube made possible television and led to the invention of the transistor a new means of controlling electronic impulses. Image of a vacuum tube and transistor together comparing size. Shows a man using a retro rotary dial telephone, image of finger dialing numbers on a vintage rotary telephone. Image of a vintage newspaper wire photo machine. CU of Trans World passenger airliner (plane), a Lockheed L-1049 Constellation in flight. Shows cockpit of Lockheed Constellation, pilot, co-pilot and Flight engineer.