TELEGRAPH, a word derived from the Greek, and which is very properly:giv en to an instrument, by means of which information may be almost instantaneous ly conveyed to a considerable distance. The telegraph, though it has been gene rally known and used by the moderns only for a few years, is by no means a modern invention. There is reason to believe, that amongst the Greeks there was some sort of telegraph in use. The burning of Troy was certainly known in Greece very soon after it happened, and before any person had returned from thence. Now that was altogether so tedious a piece of busi ness, that conjecture never could have supplied the place of information. A Greek play begins with a scene in which a watchman descends from the top of a tower in Greece, and gives the informa tion that Troy was taken. "1 have been looking out these ten years (says he) to see when that would happen, and this night it is done." Of the antiquity of a mode of conveying intelligence quickly, to a great distance, this is certainly a proof. The Chinese, when they send couriers on the great canal, or when any great man tra vels there, make signals, by fire, from one day's journey to another, to have every thing prepared ; and most of the barbar ous nations used formerly to give the• alarm of war by fires lighted on the hills or rising grounds.
It does not appear that the moderns had thought of such a machine as a telegraph, till the year 1663, when the Marquis of Worcester, in his "Century of Inven tions," affirmed that he had discovered " a method by which, at a window, as far as eye can discover black from white, man may hold discourse with his corres pondent, without noise made or notice taken ; being according to occasion giv en, or means afforded, ex re rata, and no need of provision before hand ; though much better if foreseen, and course tak en by mutual consent of parties." This could be done only by means of a tele graph, which, in the next sentence, is declared to have been rendered so per fect, that by means of it the correspon dence could be carried on by night as well as by day, though as dark as pitch is black." About forty years afterwards, M. Amon tons proposed a new telegraph. His me thod was this : Let there be people plac ed in several stations, at such a distance from one ahother, that, by the help of a telescope, a man in one station may see a signal made in the next before him ; he must immediately make the same signal, that it may be seen by persons in the sta tion next after him, who are to communi cate it to those in the following station, and so on. These signals may be as let
ters of the alphabet, or as a cypher, un derstood only by the two persons who are in the distant places, and not by those who make the signals. The person in the second station making the signal to the person in the third the very moment he sees it in the first, the news may be carried to the greatest distance in as little time as is necessary to make the signals in the first station. The distance of the several stations, which must be as few as possible, is measured by the reach of a telescope. Amontons tried this method in' a small tract of land, before several persons of the highest rank at the court of France. It was not, however, till the French revolution that the telegraph was applied to useful purposes.
Whether M. Chappe, who is said to have invented the telegraph first used by the French about the end of 1793, knew any thing of Amonton's invention or not, it is impossible to say ; but his telegraph was constructed on principles nearly si milar. The manner of using this tele graph was as follows : At the first station, which was on the roof of the palace of the Louvre at Paris, M. Chappe, the in ventor, received in writing from the Com mittee of Public Welfare, the words to be sent to Lisle, near which the French ar my at that time was. An upright post was erected on the Louvre, at the top of which were two transverse arms, movea ble in c.11 directions by a single piece of mechanism, and with inconceivable rapi dity. He invented a number of positions for these arms, which stood as signs for the letters of the alphabet ; and these, for the greater celerity and simplicity, he reduced in number as much as possi ble. The grammarian will easily con ceive that sixteen signs may amply supply all the letters of the alphabet, since some letters may be omitted, not only without detriment, but with advantage. These signs, as they were arbitrary, could be changed every week ; so that the 'sign of B for one day might be the sign of M the next ; and it was only necessary that the persons at the extremities should know the key. The intermediate ope rators were only instructed generally in these sixteen signals ; which were so distinct, so marked, so different the one from the other, that they were easily re. membered.