Discoveries and Inventions of the Nineteenth Century

power of the pile to decompose water; and the method of communicating the signals was based upon this property. Sömmering proposed to arrange thirty-five pairs of electrodes, formed by gold pins passed through the bottom of a glass vessel containing acidulated water. Each pair of pins was marked by a letter of the alphabet or a numeral, and attached to distinct wires, which could be put into connection with a pile at the sending station. The signals were made by the gas evolved from these electrodes indicating the letter intended. The number of wires required and the slowness of working were great objections, and this system never came into practical use, although it was afterwards proposed to diminish the number of the wires from thirty-five to two—by so varying the amounts of gas given off and the periods of time as to form an intelligible system of signals. Ten or twelve years after, Mr. Ronalds, of Hammersmith, invented an ingenious system by which letters on a dial could be pointed out at a distance by frictional electricity. Two dials, on which the letters, &c., were marked, were each placed behind a screen having an aperture, which permitted only one letter to be seen at once; and the dial was mounted on the seconds arbor of a clock with a dead-beat escapement. A pair of pith balls hung in front, insulated and connected by means of an insulated wire with the similar pair at the other end of the line, where the other clock and dial were placed. The 549clocks were regulated to go as nearly as possible at the same rate, so that at each end of the line the same letters were simultaneously displayed. It was easy, however, at any time to start the clocks together at the same letter by a signal previously agreed upon, and all that was really required was a synchronous motion of the discs during the time the signals were being sent. The insulated wire received from a small electrical machine a charge, which caused the pith balls at both ends to diverge; and the moment the wire was discharged, the balls collapsed suddenly and simultaneously, and this discharge was effected by the sender of the message at the instant that the letter he wished to indicate appeared at the opening in front of his dial. Since the same letter was at the same instant visible at the other end also, it was indicated to the receiver of the message by the collapse of the pith balls. Ronalds worked this telegraph experimentally with a wire 525 ft. long, but it was never adopted practically. On communicating to the Admiralty the power of his invention, he was informed that “telegraphs of any kind were wholly unnecessary, and no other than the one in use would be adopted.” The memorable discovery of electro-magnetism by Œrsted in 1819 was soon followed by attempts to apply it to the production of signals at a distance. Ampère first pointed out the possibility of making an electric telegraph with needles surrounded by wires; but he proposed to have a separate needle and wire for each signal to be transmitted. If Ampère had but thought of producing signals by different combinations of two movements, as Schweigger had before suggested for Sömmering’s telegraph, thus making two wires and two needles suffice, the practical introduction of the electric telegraph would have dated some twenty years earlier than it actually did. In 1835 Baron Schilling exhibited an electric telegraph with five magnetic needles, and he afterwards improved upon it so far as to reduce the number of needles and conductors to one—for to him the happy thought seems first to have occurred that one needle could be made to produce many signals by different combinations of its movements—sometimes to the right, sometimes to the left. Thus two movements to the left might stand for A, three for B, four for C, one to left followed by one to left for D, and so on. Schilling’s apparatus does not appear to have had the requisite qualities for practical working on the large scale. From this time, however, telegraphic inventions succeeded each other rapidly, and we meet with the names of Gauss, Weber, Steinheil, and others, as inventors and discoverers in the region of practical science which was now fairly opened, The first two used the magneto-electric machine to give motion to the needle; and the thought of using the metals of the railway line as conductors having occurred to Gauss, he found, on making the attempt, that the insulation was imperfect, but he perceived that the great apparent conductibility of the earth would allow of its being substituted for one of the metallic communicators. But the first who succeeded, after long and persevering effort, in giving a practical character to the electric telegraph, was undoubtedly Professor Wheatstone. He had for some years been engaged in electrical researches before, in 1837–-a memorable year for telegraphic inventions—he took out a patent in conjunction with Mr. W. Fothergill Cooke. In their telegraph there were five magnetic needles, arranged in a horizontal row, each needle being in a vertical position, and the various letters of the alphabet were indicated by the convergence of the needles towards the point at which the letter was marked on the dial. The first electric telegraph constructed 550in England was made on this system on the London and Blackwall Railway. In 1838, Messrs. Wheatstone and Cooke had reduced the number of needles to two, and many other improvements were effected in the apparatus for signalling, it being made possible for any number of intermediate stations to receive the messages. Several great railway companies erected lines with five lines of wire, but the expense of so many conductors was found to be considerable, and Messrs. Cooke and Wheatstone, after reducing the number of needles and conductors to two, ultimately (1845) patented an instrument with a single needle. It was about this time that an incident occurred which strongly drew the attention of the general public to the electric telegraph, which had, up to that time, been considered as the more immediate concern of the railway companies. A foul crime had been committed at Salthill, by the murder of a woman named Hart; and Tawell, the suspected murderer, was traced to Slough station, and there it was found he had taken the train to London; a description of his person was telegraphed, with instructions to the police to watch his movements on his arrival at Paddington. He was accordingly followed, apprehended, tried, convicted, and executed. This incident has been graphically and circumstantially described by Sir Francis B. Head, in connection with an anecdote recording a curiously expressed recognition of the value of the telegraph in furthering the ends of justice. We give the passage in full: “Whatever may have been his fears, his hopes, his fancies, or his thoughts, there suddenly flashed along the wires of the electric telegraph, which were stretched close beside him, the following words: ‘A murder has just been committed at Salthill, and the suspected murderer was seen to take a first-class ticket for London by the train which left Slough at 7·42 p.m. He is in the garb of a Quaker, with a brown great-coat on, which reaches nearly down to his feet. He is in the last compartment of the second first-class carriage.’ And yet, fast as these words flew like lightning past him, the information they contained, with all its details, as well as every secret thought that had preceded them, had already consecutively flown millions of times faster; indeed, at the very instant that, within the walls of the little cottage at Slough, there had been uttered that dreadful scream, it had simultaneously reached the judgment-seat of Heaven! On arriving at the Paddington Station, after mingling for some moments with the crowd, he got into an omnibus, and as it rumbled along he probably felt that his identity was every minute becoming confounded and confused by the exchange of fellow-passengers for strangers, that was constantly taking place. But all the time he was thinking, the cad of the omnibus—a policeman in disguise—knew that he held his victim like a rat in a cage. Without, however, apparently taking the slightest notice of him, he took one sixpence, gave change for a shilling, handed out this lady, stuffed in that one, until, arriving at the Bank, the guilty man, stooping as he walked towards the carriage door, descended the steps, paid his fare, crossed over to the Duke of Wellington’s statue, where, pausing for a few moments, anxiously to gaze around him, he proceeded to the Jerusalem Coffee-house, thence over London Bridge to the Leopard Coffee-house in the Borough, and, finally, to a lodging-house in Scott’s Yard, Cannon Street. He probably fancied that, by making so many turns and doubles, he had not only effectually puzzled all pursuit, but that his appearance at so many coffee-houses would assist him, if necessary, in proving an alibi; but, whatever may have been his motives or his thoughts, he had scarcely entered the lodging when the policeman—who, like a wolf, had followed 551him every step of the way—opening his door, very calmly said to him—the words, no doubt, were infinitely more appalling to him even than the scream that had been haunting him—‘Haven’t you just come from Slough?’ The monosyllable, ‘No,’ confusedly uttered in reply, substantiated his guilt. The policeman made him his prisoner; he was thrown into jail, tried, found guilty of wilful murder, and hanged. A few months afterwards, we happened to be travelling by rail from Paddington to Slough, in a carriage filled with people all strangers to one another. Like English travellers, they were mute. For nearly fifteen miles no one had uttered a single word, until a short-bodied, short-necked, short-nosed, exceedingly respectable-looking man in the corner, fixing his eyes on the apparently fleeting posts and rails of the electric telegraph, significantly nodded to us as he muttered aloud, ‘Them’s the cords that hung John Tawell!’” So far we have followed Wheatstone and Cooke, because these gentlemen were the first who in any country made the electric telegraph a success on the great scale. Elsewhere than in England, laboratories and observatories had been connected by experimental lines, and models had been exhibited to Emperors, but these two Englishmen were the first to construct a telegraph for practical use. It must not, however, be supposed that they are entitled to be considered the exclusive inventors of the electric telegraph, for we have already named other distinguished investigators who contributed their share to this remarkable invention. And some years before Wheatstone and Cooke had patented their first needle telegraph, the first ideas of a system which has largely superseded the needles for ordinary telegraphic purposes, had presented themselves to a mind capable of developing them into the most efficient form of telegraphic apparatus which we possess. In October, 1832, among the passengers on board the steamship Sully, bound from France to the United States, was a talented American artist who had gained some reputation in his profession. A casual conversation with his fellow-passengers on electricity, and the plan by which Franklin drew it from the clouds along a slender wire, suggested to the artist the possibility of thus communicating intelligence by signals at a distance. He named his notion to a fellow-passenger, Dr. Jackson, an American professor, who had devoted some attention to electrical science, and this gentleman suggested several possible (and impossible) methods in which the thing might, as he thought, be accomplished. None of these suggestions, however, indicated the direction in which the idea afterwards took practical form in Morse’s hands. Jackson had among his baggage in the hold, and therefore inaccessible on the voyage, a galvanic battery and an electro-magnet, and these he described to the painter by the aid of rough sketches. When, some years afterwards, Morse had realized his ideas of electric communication, and success