Transport and means of communication

In the past a messenger or caravan was needed to send news far away. In the 19th century electric current began to carry messages in an instant. The telegraph is a device that sends written messages quickly over long distances. In 1832 the Russian scientist Pavel Schilling made an electric telegraph; in 1837 the American Samuel Morse developed his telegraph and a special alphabet of dots and dashes, Morse code. The distress signal at sea, “SOS”, is three dots, three dashes and three dots. The telephone was patented in 1876 by Alexander Graham Bell, who was born in Scotland and worked in America. Radio is wireless communication: on 7 May 1895 the Russian scientist Alexander Popov demonstrated his radio receiver; in the same years the Italian Guglielmo Marconi also developed radio, so it is fair to see this discovery as the work of several scientists. Radio waves travel at about 300,000 km per second. Radio and television, and contact with aeroplanes and spacecraft, work through such waves. Today the fax, teleprinter and mobile phone are also means of communication.