Man has used many ingenious methods to solve the problem of long-range communications. He has used fiery beacons on hilltops (as the ancient Romans did), and smoke signals like the American Indians. But these all became primitive with the invention of the telegraph.

We owe this invention to the work of a number of scientists. As early as 1753 one scientist had written in a Scottish journal about a plan to send messages over a distance by means of electricity. Little attention was paid to the suggestion. It was only during the middle of the nineteenth century that the first telegraph lines came into operation. These were largely the work of the British scientists Wheatstone and Cooke and of the American, Morse.

Basically the telegraph consists of a transmitter which converts a message into electrical signals. The short signals are called dots and the long signals dashes. These dots and dashes travel along the telegraph wires and are picked up by a receiving set. The signals then move a metal point that writes the dots and dashes on a paper tape. These dots and dashes are a code written message. From 1850 until the 1920s, when teleprinters came into operation, Morse was the code most used. The telegraph is being superseded by computer networks.