The story of the electric telegraph as a practical proposition begins with the arrangements patented by W.F. Cooke and Wheatstone in 1837, but many inventors had tried, without great success, to make a telegraph before then. The earliest account of a workable electric telegraph was given in a letter signed only 'C.M.' in the Scots Magazine of 1753. This telegraph required 26 insulated wires running between the sender and the receiver. One wire corresponded to each letter of the alphabet. The operator sending a message had an electrostatic machine which he could connect to any one of the wires to indicate a letter. At the receiver the wires either ended with a spark gap or were arranged to attract small pieces of paper when charged. This telegraph had two fundamental disadvantages: it required a separate wire for each signal and because it depended on static electricity it needed a quality of insulation which could not be maintained over any great distance.

Inspec keywords: telegraphy; electric fields; electrostatic devices; spark gaps; history

Other keywords: insulated wire; spark gap; static electricity; electric telegraph; early telegraphy; Sir Charles Wheatstone; electrostatic machine

Subjects: Telegraphy