The Electric Telegraph has had considerable antiquity claimed for it, but it is pretty certain that the discovery made by Doctor Watson, in 1747, that electricity would pass through wires, and that the earth would complete the circuit, gave the first impetus to the Electric Telegraph. Doctor Watson was enabled to transmit shocks across the Thames, and made experiments at Shooters Hill. Franklin did likewise across the Schuykill in 1748, and De Luc performed the same experiments on the Lake of Geneva. Both Lesage and Lomond caused pith balls to diverge at distant points, and in 1794 Reizen made use of the electric spark for transmitting signals, and made strips of foil show out certain letters when the spark passed. He had a wire and a return wire for each letter of the alphabet.
These were all slow advances, and subsequently many learned men in Europe sought to improve upon the ideas then promulgated. We read of telegraphs constructed at Madrid by Salvá and Betancourt in 1797 and 1798, one extending for more than twenty miles. The first-named gentleman finally proposed to substitute the Voltaic pile for the usual machine, and Ronalds and Dyar in England and New York respectively employed frictional electricity with some success. The latter sent charges of frictional electricity through a wire, and they were recorded by being made to pass through litmus paper. The distances between the discharges were intended to indicate the letters of the alphabet, but even if the experiment was fairly tried it failed, for little was heard of the result.
After the invention of Volta’s pile, which Salvá wished to adopt, Sömmering began his experiments. He used thirty-five wires, set up vertically at the bottom of a glass reservoir of water, and terminating in gold points. These wires ended in the opposite direction in brass plates attached to a bar of wood. At one end the points and at the other the plates bore the same letters respectively; hydrogen at one gold point, and oxygen at another, and two different letters were indicated when the current was sent through any two plates. This arrangement was afterwards improved upon, and only two wires retained.
It was not until electro-magnetism had been developed, however, that Œrstead found out the power of electricity to deflect the magnetised needle, and in 1820, Scheweigger added a “multiplier.” Then came Arago into the field with his discovery, that a “wire carrying a current could magnetise a steel rod.” Ampère substituted a helix for a straight wire, and Sturgeon used soft iron for steel, and developed the electro-magnet. Daniell’s battery, and Faraday’s discoveries of magneto-electricity and the induction coil were the means of putting a constant supply of electricity at the service of the telegraph and so on, till 1830 brought out a more practical method introduced by Schilling.
In that year Baron Schilling made a telegraph, and exhibited it in 1832 at Bonn. This invention, with five vertical needles, was shown to Mr. Cooke in 1836. But in 1834, Gauss and Weber had succeeded in sending signals by means of a voltaic current acting upon a magnetised needle, and this apparatus was really the first practical electric telegraph in use, and it was much improved by Professor Steinheil of Munich. They employed a magnetic-electro machine, and caused a bar to move in certain directions to indicate certain letters of the alphabet. This was really of value, but Steinheil, the pupil of Gauss, assisted by his government, employed only a single wire, and made the earth complete the circuit for him instead of having a return wire as his predecessors had. This telegraph was perfected by a series of bells, which gave different tones for different letters, and he also caused the needle to make certain tracings as it moved upon a paper slip, something like the Morse pattern, which was completed in 1837.
Professor Morse, in 1832, conceived the idea of an electric telegraph but his claim was disputed by a Doctor Jackson, who was on the same vessel when the subject was discussed. We need not enter into the details of the controversy. Mr. Morse won the day, and patented his invention.
“It was once a popular fallacy in England and elsewhere that Messrs. Cooke and Wheatstone were the original inventors of the electric telegraph. The electric telegraph had, properly speaking, no inventor.... Messrs. Cooke and Wheatstone were, however, the first who established a telegraph for practical purposes comparatively on a large scale, and in which the public were more nearly concerned.... Therefore it was that the names of these enterprising and talented inventors came to the public ear, while those of Ampère and Steinheil remained comparatively unknown.[17] The telegraph, as used in Great Britain, was the result of the co-operation of Professors Cooke and Wheatstone.
Mr. Cooke, in 1836, having seen the needle telegraph when in Heidelberg, made certain designs, and soon entered into partnership with Professor Wheatstone for the application of electric telegraphs to railways. Their apparatus with five needles and five wires was put up on the London and North-Western (then London and Birmingham) and Great Western lines, but proved too expensive. The instrument was subsequently modified, and is used on the English railways still.
Fig. 242.—Cell.