TF:LEORAPII (from "distant," and stpdow, " write "), a machine or process for communicating intelligence to a distance, usually by means of preconcerted signals, to which some conventional moaning is attached. The name semaphore (from " a sign," and fpipte, " bear"), was also applied to some of the machines used fur effecting telegraphic communication; which, in an extended sense, may be considered to embrace every means of conveying intelligenco by gestures and visible signals, as flags, lanterns, rockets, blue-lights, beecon-fires, Lc., or by audible signals, as the firing of guns, tho blow ing of trumpets, the beating of drums or gongs, &c, as well as by the machines specially provided for the purpose.
Although telegraphic communleatien, as a inearis of conveying any required Intelligence, is an invention of recent date, the use of signals for the speedy transmission of such brief messages as might be pre siously arranged between persons, is a practice derived from tho most remote, antiquity. The use of beacon fires, for example, as a means of giving speedy warning of the approach of an enemy, Is alluded to by the prophet Jeremiah, who wrote about six centuries before the Christian era, and who warns the Benjiunitcs to "set up a sign of fire in Beth-haccerem ; for evil," he adds, " appeareth out of the north, and great destruction." (Jeremiah, vl. 1.) The fine description given In his 'Agamemnon,' of the application of a line of tire signals to communicate the Intelligence of the fall of Troy, is often referred to as an early Instance of this kind of telegraphic despatch. This simple means of spreading an alarm, or communicating intelli gence, is described by Scott in the' Lay of the Last ilinstrel ;' and in a note he refers to an Act of the Scottish parliament in 1455, c. 48, which directs that ono bale or faggot shall be warning of the approach of the English in any manner ; two bales, that they are corning indeed; and four bales blazing beadle each other, that the enemy are in great force. Such signals, though best adapted to give information by night, were also available in the daytime, when they appeared as columns of dense smoke. Torches held in the hand and moved in any particular manner, or alternately displayed and hidden behind a screen, were also used in ancient times as signals Pulyblus describes two somewhat complicated methods of telegraphing by means of torches ; and Bishop Wilkins, in his curious work entitled ' Mercury; or the Secret and Swift Messenger,' after describing this telegraph of i'olybius. mentions another which requires only three lights or torches to indicate the twenty-four necessary letters of the alphabet, which aro, according to this plan, which he gives on the authority of Joachimus Forties, to be divided into three classes of eight letters each. The first class is represented by one torch, the second by two, and the third by three ; and the number of the letter by the number of times which the torches are elevated or discovered. Similar to this, is the night telegraph contrived by the Rev. James Bremner, of the Shetland Islands, and rewarded by the Society of Arts in 1816. (' Soc. Trans., xxxiv.) A single light constitutes the whole apparatus, and the whole operation consists in its alternate exhibition and concealment. This plan had been found suitable for distances of twenty miles and upwards, and had been successfully put in operation between the lighthouse on Copeland Island and Port Patrick on the opposite side of the Irish Channel. Bishop Wilkins also describes a method which
depends upon the relative positions of two lights attached to long poles, and which, he says, " for its quickness and speed is much to be preferred before any of the rest." This plan came very near to the principle upon 'which some of the subsequent telegraphic systems depended. in suggesting the use of extended lines of telegraphic communication, he further hints at the application of the telescope (or, as Ise styles it, ' Galileus his perspective '), to the deciphering of distant signals. • Other writers, such as Kircher, Schottus, and Kessler, have pub lished plans for telegraphic signals. Kessler proposed to cut out such characters as it was desired to show in the ends of a cask, which was to be elevated with a light enclosed in it. The Marquess of Worcester also, in his ' Century of Inventions,' 1663, announces, " How at a window, as far ns the eye can discover black from white, a man may hold discourse with his correspondeut, without noise made or notice taken," lt:c.; and again, " A way to do it by night as well as by day, though as dark as pitch is black." But the earliest well-defined plan of telegraphic communication appears to be that described in a paper addressed to the Royal Society in 1684, by Dr. Robert Hooke, and published in 1726 in Derham's collection of his ' Philosophical Ex periments and Observations,' pp. 142.150, " showing a way how to communicate one's mind at great distances." Hooke's scheme will be understood by referring to fig. 1, which represents an elevated frame-work supporting a panel or screen, a, behind which were to be suspended a number of symbols or devices, formed of deal plank, of the various shapes represented by the small black figures. The first twenty-four of dime, which consist entirely of straight lines, were to stand for alphabetic characters ; and the sir devices consisting of curved lines wero to be used as arbitrary signals. Whenever it was desired to display any of these characters, they were to be drawn from behind the screen by a rope e, passing over pulleys in the fraine-work, and so rendered visible in the open space at 11. These telegraphs were to be erected upon elevated ststions, and telescopes were to be used by the observers. The order of connection between the signs employed and the letters of the alphabet might, it is explained, be infinitely varied, for the sake of secrecy ; and none of the parties employed, excepting those at the terminal stations, need have any knowledge of the message communicated. Hooke further proposed a scheme for night communication by insane of lights disposed in a certain order About twenty years after the date of Hooke's paper, Amontons brought forward a similar plan in France. Some other individuals subsequently devised similar schemes, but nothing was effected in the practical application of telegraphic communication until the wars of the French revolution. Macdonald states that, " Following the principles laid down by Dr. Hooke, in 1684, Dupuis, in France, invented the French telegraph, which Don Gualtier, a !monk of the order of Citeaux, in 1781, modified, and proposed to Condorcet, Milli, and Dr. Franklin, who recommended it to the French government." The telegraph brought into use in 1793 or 1794, by M. Chappe, was, as will be seen by fig. 2, a very superior machine to that of Dr. Hooke.