chapter 3._
ELECTRICITY: A. D. 1753-1820. The beginnings of the Electric Telegraph.
"The first actual suggestion of an electric telegraph was made in an anonymous letter published in the Scots Magazine at Edinburgh, February 17th, 1753. The letter is initialed 'C. M.,' and many attempts have been made to discover the author's identity. ... The suggestions made in this letter were that a set of twenty-six wires should be stretched upon insulated supports between the two places which it was desired to put in connection, and at each end of every wire a metallic ball was to be suspended, having under it a letter of the alphabet inscribed upon a piece of paper. ... The message was to be read off at the receiving station by observing the letters which were successively attracted by their corresponding balls, as soon as the wires attached to the latter received a charge from the distant conductor. In 1787 Monsieur Lomond, of Paris, made the very important step of reducing the twenty-six wires to one, and indicating the different letters by various combinations of simple movements of an indicator, consisting of a pith-ball suspended by means of a thread from a conductor in contact with the wire. ... In the year 1790 Chappe, the inventor of the semaphore, or optico-mechanical telegraph, which was in practical use previous to the introduction of the electric telegraph, devised a means of communication, consisting of two clocks regulated so that the second hands moved in unison, and pointed at the same instant to the same figures. ... In the early form of the apparatus, the exact moment at which the observer at the receiving station should read off the figure to which the hand pointed was indicated by means of a sound signal produced by the primitive method of striking a copper stew pan, but the inventor soon adopted the plan of giving electrical signals instead of sound signals. ... In 1795 Don Francisco Salva ... suggested ... that instead of twenty-six wires being used, one for each letter, six or eight wires· only should be employed, each charged by a Leyden jar, and that different letters should be formed by means of various combinations of signals from these. ... Mr. (afterwards Sir Francis) Ronalds ... took up the subject of telegraphy in the year 1816, and published an account of his experiments in 1823," based on the same idea as that of Chappe. ... "Ronalds drew up a sort of telegraphic code by which words, and sometimes even complete sentences, could be transmitted by only three discharges. ... Ronalds completely proved the practicability of his plan, not only on [a] short underground line, .... but also upon an overhead line some eight miles in length, constructed by carrying a telegraph wire backwards and forwards over a wooden frame-work erected in his garden at Hammersmith. ... The first attempt to employ voltaic electricity in telegraphy was made by Don Francisco Salva, whose frictional telegraph has already been referred to. On the 14th of May, 1800, Salva read a paper on 'Galvanism and its application to Telegraphy' before the Academy of Sciences at Barcelona, in which he described a number of experiments which he had made in telegraphing over a line some 310 metres in length. ... A few years later he applied the then recent discovery of the Voltaic pile to the same purpose, the liberation of bubbles of gas by the decomposition of water at the receiving station being the method adopted for indicating the passage of the signals. A telegraph of a very similar character was devised by Sömmering, and described in a paper communicated by the inventor to the Munich Academy of Sciences in 1809. Sömmering used a set of thirty-five wires corresponding to the twenty-five letters of the German alphabet and the ten numerals. ... Oersted's discovery of the action of the electric current upon a suspended magnetic needle provided a new and much more hopeful method of applying the electric current to telegraphy. The great French astronomer Laplace appears to have been the first to suggest this application of Oersted's discovery, and he was followed shortly afterwards by Ampere, who in the year 1820 read a paper before the Paris Academy of Sciences."
_G. W. De Tunzelmann, Electricity in Modern Life,