TELEGRAPH

, a machine brought into use by the French nation, in the year 1793, contrived to communicate words or signals from one person to another at a great distance, in a very small space of time.

The Telegraph it seems was originally the invention of William Amontons, an ingenious philosopher, born in Normandy in the year 1663. See his life in this Dictionary, vol. 1, pa. 105; where it is related that he pointed out a method to acquaint people at a great distance, and in a very little time, with whatever one pleased. This method was as follows: let persons be placed in several stations, at such distances from each other, that, by the help of a telescope, a man in one slation may see a signal made by the next before him: this person immediately repeats the same signal to the third man; and this again to a fourth, and so on through all the stations to the last.

This, with considerable improvements, it seems has lately been brought into use by the French, and called a Telegraph. It is said they have availed themselves of this contrivance to good purpose, in the present war; and from the utility of the invention, it has also just been brought into use in this country.

The following account of this curious instrument is copied from Barrere's report in the sitting of the French Convention of August 15, 1794.—“The new-invented telegraphic language of signals is an artful contrivance to transmit thoughts, in a peculiar language, from one distance to another, by means of machines, which are placed at different distances, of from 12 to 15 miles from one another, so that the expression reaches a very distant place in the space of a few minutes. Last year an experiment of this invention was tried in the presence of several Commissioners of the Convention. From the favourable report which the latter made of the efficacy of the contrivance, the Committee of Public Welfare tried every effort to establish, by this means, a correspondence between Paris and the frontier places, beginning with Lisle. Almost a whole twelvemonth has been spent in collecting the necessary instruments for the machines, and to teach the people employed how to use them. At present, the telegraphic language of signals is prepared in such a manner, that a correspondence may be conducted with Lisle upon every subject, and that every thing, nay even proper names, may be expressed; an answer may be received, and the correspondence thus be renewed several times a day. The machines are the invention of Citizen Chappe, and were constructed under his own eye; he also directs their establishment at Paris. They have the advantage of resisting the changes in the atmosphere, and the inclemencies of the seasons. The only thing which can interrupt their effect is, if the weather is so very bad and turbid that the objects and signals cannot be distinguished. By this invention, remoteness and distance almost disappear; and all the communications of correspondence are effected with the rapidity of the twinkling of an eye. The operations of Government can be very much facilitated by this contrivance, and the unity of the Republic can be the more consolidated by the speedy communication with all its parts. The greatest advantage which can be derived from this correspondence is, that, if one chooses, its object shall only be known to certain individuals, or to one individual alone, or to the extremities of any distance; so that the Committee of Public Welfare may now correspond with the Representative of the People at Lisle without any other persons getting acquainted with the object of the correspondence. Hence it follows that, were Lisle even besieged, we should know every thing at Paris that might happen in that place, and could send thither the Decrees of the Convention without the enemy's being able to discover or to prevent it.”—The description and figure of the French machine, as given in some English prints, are as follow.

Explanation of the Machine (Telegraph) placed on the Mountain of Bellville, near Paris, for the purpose of communicating Intelligence.

AA is a beam or mast of wood, placed upright on a rising ground (fig. 3, pl. 28) which is about 15 or 16 feet high. BB is a beam or balance, moving upon the centre AA. This balance-beam may be placed vertically, or horizontally, or any how inclined, by means of strong cords, which are fixed to the wheel D, on the edge of which is a double groove, to receive the two chords. This balance is about 11 or 12 feet long, and 9 inches broad, having at the ends two pieces of wood CC, which likewise turn upon angles by means of four other cords that pass through the axis of the main balance, otherwise the balance would derange the cords; the pieces C are each about 3 feet long, and may be placed either to the right or lest, straight or square with the balance-beam. By means of these three, the combination of movement is said to be very extensive, remarkably simple, and easy to perform. Below is a small wooden gouge or hut, in which a person is employed to observe the movements of the machine. In the mountain nearest to this, another person is to repeat these movements, and a third to write them down. The time taken up for each movement is 20 seconds; of which the motion alone is 4 seconds, the other 16 the machine is stationary. The stations of this machine are about 3 or 4 leagues distance; and there is an observatory near the Committee of Public | Safety to observe the motions of the last, which is at Bellville. The signs are sometimes made in words, and sometimes in letters; when in words, a small flag is hoisted, and, as the alphabet may be changed at pleasure, it is only the corresponding person who knows the meaning of the signs. In general, news are given every day, about 11 or 12 o'clock; but the people in the wooden gouge observe from time to time, and, as soon as a certain signal is given and answered, they begin, from one end to the other, to move the machine. It is painted of a dark brown colour.

Such is the account given of the French invention. Various improved contrivances have been since made in England, and a pamphlet has lately been published, giving an account of some of them, by the Rev. J. Gamble, under the title of, Observations and Telegraphic Experiments, from whence the following remarks are extracted.

The object proposed is, to obtain an intelligible figurative language, which may be distinguished at a distance, and by which the obvious delay in the dispatch of orders or information by messenger may be avoided.

On first reflection we find the practical modes of such distant communication must be confined to Sound and Vision. Each of which is in a great degree subject to the state of the atmosphere: as, independent of the wind's direction, it is known that the air is sometimes so far deprived of its elasticity, or whatever other quality the conveyance of sound depends on, that the heaviest ordnance is scarce heard farther than the shot flies; it is also well known, that in thick hazy weather the largest objects become totally obscured at a short distance. No instrument therefore designed for the purpose can be perfect. We can only endeavour to diminish these irremediable defects as much as may be.

It seems the Romans had a method in their walled cities, either by a hollow formed in the masonry, or by tubes affixed to it, so to confine and augment sound as to convey information to any part they wished; and in lofty houses it is now sometimes the custom to have a pipe, by way of speaking trumpet, to give orders from the upper apartments to the lower: by this mode of confining sound its volume may be carried to a very great distance; but beyond a certain extent the sound, losing articulation, would only convey alarm, not give directions.

Every city among the antients had its watch-towers; and the castra stativa of the Romans, had always some spot, elevated either by nature or art, from whence signals were given to the troops cantoned or foraging in the neighbourhood. But I believe they had not arrived to greater refinement than that on seeing a certain signal they were immediately to repair to their appointed stations.

A beacon or bonfire made of the first inflammable materials that offered, as the most obvious, is perhaps the most antient mode of general alarm; and by being previously concerted, the number or point where the fires appeared might have its particular intelligence affixed. The same observations may be referred to the throwing up of rockets, whose number or point from whence thrown may have its affixed signification.

Flags or ensigns with their various devices are of earliest invention, especially at sea; where, from the first idea, which most probably was that of a vane to shew the direction of the wind, they have been long adopted as the distinguishing mark of nations, and are now so neatly combined by the ingenuity of a great naval commander, that by his system every requisite order and question is received and answered by the most distant ships of a fleet.

To the adopting this or a similar mode in land service, the following are objections: That in the latter case, the variety of matter necessary to be conveyed, is so infinitely greater, that the combinations would become too complicated. And if the person for whom the information is intended should be in the direction of the wind, the flag would then present a straight line only, and at a little distance be scarce visible. The Romans were so well aware of this inconvenience of flags, that many of their standards were solid, and the name manipulus denotes the rudest of their modes, which was a truss of hay fixed on a pole.

The principle of water always keeping its own level has been suggested, as a mode of conveying intelligence, by Mr. Daniel Brent, of Rotherhithe, and put in practice on a small scale. As for example, suppose a pipe AB to reach from London to Dover, and to have a per- pendicular tube connected to each extremity, as AC and BD. Then, if the pipe be constantly filled with water to a certain height, as AE, it will also rise to its level in the opposite perpendicular tube BF; and if one inch of water be added in the tube AC, it will almost instantly produce a similar elevation of the tube BD; so that by corresponding letters being adapted to the tubes AC and BD, at different heights, intelligence might be conveyed. But the method is liable to such objections, that it is not likely it can ever be adopted to facilitate the object of very distant communication.

Full as many, if not greater objections, will perhaps operate against every mode of electricity being used as the vehicle of information.—And the requisite magnitude of painted or illuminated letters offers an unsurmountable obstacle; besides, in them one object would be lost, that of the language being figurative.

As to the French machine, it is evident that to every angular change of the greater beam or of the lesser end arms, a different letter or figure may be annexed. But where the whole difference consists in the variation of the angle of the greater or lesser pieces, much error may be expected, from the inaccuracy either of the operator or the observer: besides other inconveniences arising from the great magnitude of the machinery.

Another idea is perfectly numerical; which is to raise and depress a flag or curtain a certain number of times for each letter, according to a previously concerted system: as, suppose one elevation to mean A, two to mean B, and so on through the alphabet. But in this case, the least inaccuracy in giving or noting the | number changes the letter; and besides, the last letters of the alphabet would be a tedious operation.

Another method that has been proposed, is an ingenious combination of the magnetical experiment of Comus, and the telescopic micrometer. But as this is only an imperfect idea of Mr. Garnet's very ingenious machine, described in the latter part of this article, no farther notice need be taken of it here.

Mr. Gamble then proposes one on a new idea of his own. The principle of it is simply that of a Venetian blind, or rather what are called the lever boards of a brewhouse, which, when horizontal, present so small a surface to the distant observer, as to be lost to his view, but are capable of being in an instant converted into a screen of a magnitude adapted to the required distance of vision.—Let AB and CD (fig. 4. pl. 28), two upright posts sixed in the ground, and joined by the braces BD and EF, be considered as the frame work for 9 lever boards working upon centres in EB and DF, and opening in three divisions by iron rods connected with each three of the lever boards. Let abcd and efgh be two lesser frames fixed to the great one, having also three lever boards in each, and moving by iron rods, in the same manner as the others. If all these rods be brought so near the ground as to be in the management of the operator, he will then have five, of what may be called, keys to play on. Now as each of the handles iklmn commands three lever boards, by raising any one of them, and fixing it in its place by a catch or hook, it will give a different appearance to the machine; and by the proper variation of these sive movements, there will be more than 25 of what may be called mutations, in each of which the machine exhibits a different appearance, and to which any letter or figure may be annexed at pleasure.

Should it be required to give intelligence in more than one direction, the whose machine may be easily made to turn to different points on a strong centre, after the manner of a single-post windmill.—To use this machine by night, another frame must be connected with the back part of the Telegraph, for raising five lamps, of different colours, behind the openings of the lever boards; these lamps by night answer for the opening by day.

M. Gamble gives also particular directions for placing and using the machine, and for writing down the several figures or movements.

I shall now conclude this article with a short idea of Mr. John Garnet's most simple and ingenious contrivance. This is merely a bar or plank turning upon a centre, like the sail of a windmill, and being moved into any position, the distant observer turns the tube of a telescope into the same position, by bringing a fixed wire within it to coincide with or parallel to the bar, which is a thing extremely easy to do. The centre of motion of the bar has a small circle about it, with letters and figures around the circumference, and an index moving round with the bar, pointing to any letter or mark that the operator wishes to set the bar to, or to communicate to the observer. The eye end of the telescope without has a like index and circle, with the corresponding letters or other marks. The consequence is obvious: the telescope being turned round till its wire cover or become parallel to the bar, the index of the former necessarily points out the same letter or mark in its circle, as that of the latter, and the communication of sentiment is immediate and perfect. The use of this machine is so easy, that I have seen it put into the hands of two common labouring men, who had never seen it before, and they have immediately held a quick and distant conversation together.

The more particular description and figure of this machine, take as follows. ABDE (fig. 5, pl. 28), is the Telegraph, on whose centre of gravity C, about which it revolves, is a fixed pin, which goes through a hole or socket in the firm upright post G, and on the opposite side of which is fixed an index CI. Concentric to C, on the same post, is fixed a wooden or brass circle, of 6 or 8 inches diameter, divided into 48 equal parts, 24 of which represent the letters of the alphabet, and between the letters, numbers. So that the index, by means of the arm AB, may be moved to any letter or number. The length of the arm should be 2 1/2 or 3 feet for every mile of distance. Two revolving lamps of different colours suspended occasionally at A and B, the ends of the arm, would serve equally at night.

Let ss (fig. 6, pl. 28) represent the section of the outward tube of a telescope perpendicular to its axis, and xx the like section of the sliding or adjusting tube, on which is fixed an index II. On the part of the outward tube next to the observer, there is fixed a circle of letters and numbers, similarly divided and situated to the circle in figure 3; then the index II, by means of the sliding or adjusting tube, may be turned to any letter or number.—Now there being a cross hair, or fine silver wire fg, fixed in the focus of the eye glass, in the same direction as the index II; so that when the arm AB (fig. 5) of the Telegraph is viewed at a distance through the telescope, the cross hair may be turned, by means of the sliding tube, to the same direction of the arm AB; then the index II (fig. 6) will point to the same letter or number on its own circle, as the index 1 (fig. 5) points to on the Telegraphic circle.

If, instead of using the letters and numbers to form words at length, they be used as signals, three motions of the arm will give above a hundred thousand different signals.

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ABCDEFGHKLMNOPQRSTWXYZABCEGLMN

Entry taken from A Mathematical and Philosophical Dictionary, by Charles Hutton, 1796.

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TARTAGLIA
TATIUS (Achilles)
TAURUS
TEBET
TEETH
* TELEGRAPH
TELESCOPE
TEMPERAMENT
TENACITY
TENAILLE
TENAILLONS