Telegraph: From the 1797 Encylopaedia Britannica

The text below is from the 1797 Encyclopaedia Britannica, Volume 18, page 334. We think of the word "telegraph" as originating with Morse. The word, however, is much older than that. As you can see, thought has long been given to fast methods of long distance communication.

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TELEGRAPH (derived from [Greek letters not shown]), is the name very properly given to an instrument, by means of which information may be almost instantaneously conveyed to a considerable distance.

The telegraph, though it has been generally 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 or business, that conjecture never conld 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 information that Troy was taken. "I 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 travels there, make signals by fire from one day's journey to another, to have every thing prepared; and most of the barbarous nations used formerly to give the alarm of war by fires lighted on the hills or rising grounds.

Polybius calls the different instruments used by the ancients for communicating information [Greek text illegible] because the signals were always made by means of fire. At fir ft they communicated information of events merely by torches; but this method was of little use, because it was necessary before-hand to fix the meaning of every particular signal. Now as events are exceedingly various, it was impossible to express the greater number or them by any premeditated contrivance. It was easy, for instance, to express by signals that a fleet had arrived at such a place, because this had been foreseen, and signals accordingly had been agreed upon to denote it; but an unexpected revolt, a murder, and such accidents, as happen but too often, and require an immediate remedy, could not be communicated by such signals; because to foresee them was impossible.

Aeneas, a contemporary of Aristotle, who wrote a treatise on the duties of a general,, endeavoured to correct those imperfections, but by no means succeeded. "Those (says he) who would give signals to one another upon affairs of importance, must first prepare two vessels of earth, exactly equal in breadth and depth; and. they need be but four feet and a half deep, .and a foot and a half wide. They then must take pieces of cork, proportioned to the mouth of these vessels, but not quite so wide, that they may be let down with ease to the bottom of these vessels. They next fix in the middle of this cork a flick, which must be of equal size in both these vessels. This stick must be divided exactly and distinctly, by spaces of three inches each, in order that such events as generally happen in war may be writ on them. For example, on one of these spaces the following words may be writ: "A BODY OF HORSE ARE MARCHED INTO THE COUNTRY." On another, "A BODY OF INFANTRY, heavily armed, are arrived hither." On a third, "INFANTRY LIGHTLY ARMED." On a fourth, "HORSE AND FOOT." On another, "SHIPS," then "PROVISIONS," and so on till all the events which may probably happen in the war that is carrying on are writ down in these intervals.

This being done, each of the two vessels must have a little tube or cock of equal bigness, to let out the water in equal proportion. Then the two vessels must be filled with water; the pieces of cork, with their sticks thrust through them, must be laid upon them, and the cocks must be opened. Now, it is plain, that as these vessels are equal, the corks will sink and the sticks descend lower in the vessels, in proportion as they empty themselves. But to be more certain of this exactness, it will be proper to make the experiment first, and to examine whether all things correspond and agree together, by an uniform execution on both sides. When they are well assured of this, the two vessels must be, carried to the two places where the signals are to be made and observed as water is poured in, and the corks and sticks are put in the vessels. When any of the events which are written on the sticks shall happen, a torch or other light is raised, which must be held aloft till such time as another is raised by the party to whom it is directed. This first signal is only to give notice that both parties are ready and attentive. Then the torch or other light must be taken away, and the cocks set open. When the interval, that is, that part of the stick where the event of which notice is to be given or written, shall be fallen to a level with the vessels, then the man who gives the signal lifts up his torch; and on the other tide, the correspondent signal maker immediately turns the cock of his vessel, and looks at what is writ on that part of the stick which touches the mouth of the vessell: on which occasion, if every thing has been executed exactly and equally on both sides, both will read the same thing.

This method was defective, because it could not convey any other intelligence except what was written on the sticks, and: even that not particularly enough. With regard to all unforeseen events, it was quite useless.

A new method was invented by Cleoxenus (others say by Democlitus), and very much improved by Polybius, as he himself informs us. He describes this method as follows: Take the letters of the (Greek) alphabet, and divide them into five parts, each of which will consit of five letters, except the last division, which will have only four. Let these be fixed on a board in five columns. The man who is to give the signals is then to begin by holding up two torches, which he is to keep aloft till the other party has also shown two. This is only to show that both sides are ready. These first torches are then withdrawn. Both parties are provided with boards, on which the letters are disposed as formerly described. The person then who gives the signal is to hold up torches on the left to point out to the other party from what column he shall take the letters as they are pointed out to him. If it is to be from the first column, he holds up one torch; if from the second, two; and so on for the others. He is then to hold up torches on the right, to denote the particular letter of the column that is to be taken. Al this must have been agreed on before-hand. The man who gives the signals must have an instrument [greek text illegible], consisting of two tubes, and so placed as that, by looking through one of them, he can see only the right side, and through the other only the left, of him who is to answer. The board must be set up near this instrument; and the station on the right and left must be surrounded with a wall [greek text illegible] ten feet broad, and about the height of a man, that the torches raised above it may give a clear and strong light, and that when taken down they may be completely concealed. Let us now suppose that this information is to be communicated--A number of the auxiliaries, about a hundred, have gone over to the enemy. In the first place, words must be chosen that will convey the information in the fewest letters possible; as, A hundred Cretans have deserted, [Greek text illegible]. Having written down this sentence, it is conveyed in this manner. The first letter is a K, which is in the second column; two torches are therefore to be raised on the left hand to inform the person who receives the signals to look into that particular column. Then five torches are to be held up on the right to mark the letter K, which is the las in the column. Then four torches are to be held up in the left to point out the R. which is in the fourth column, and two on the right to show that it is the second letter of that column. The other letters are pointed out in the same manner.--Such was the [Greek text illegible] or telegraph recommended by Polybius.

But neither this nor any other method mentioned by the ancients seems ever to have been brought into general use; nor does it appear that the moderns had thought of such machine as a telegraph till the year 1663, when the Marquis of Worcestr, in his Century Of Inventions, affirmed that he had discovered "a method by which, at a window, as far as eye can discover black from white, a man may hold discourse with his correspondent, without noise made or notice taken; being according to occasion given or means afforded, ex re nata, and no need of provision before hand; though much belter if foreseen, and course taken by mutual consent of parties." This could be done only by means of a telegraph, which in the next sentence is declared to have been rendered so perfect, that by means of it the correspondence could be carried on "by night as well as by day though as dark as pitch is black."

About 40 years afterwards M. Amontons proposed a new telegraph. His method was this: Let there be: people placed in several stations, at such a distance from one another, 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 station next after him, who are to communicate it to those in the following station, and so on. These signals may be as letters of the alphabet, or as a cipher, understood 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 in 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 anything of Amontons's invention or not, it is impossible to say; but his telegraph was constructed on principles nearly similar. The manner of using this telegraph was as follows: At the first station, which was on the roof of the palace of the Louvre at Paris, M. Chappe, the inventor, received in writing, from the committee of public welfare, the word:, to be sent to Lille, near which the French army at that time was. An upright poll was erected on the Louvre, at the top of which were two transverse arms, moveable in all directions by a single piece of mechanism, and with inconceivable rapidity. 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 possible, The grammarian will easily conceive 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 operators 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 remembered. The construction of. the machine was such, that each signal was uniformly given in precisely the same manner at all times: It did not depend on the operator's manual skill and the position of the arm could never, for any one signal, be a degree higher or a degree lower, its movement being regulated mechanically.

M. Chappe having received at the Louvre the sentence; to be conveyed, gave a known signal to the second station, which was Mont Martre, to prepare. At each station there was a watch tower, where telescopes were fixed, and the person on watch gave the signal of preparation which he had received, and this communicated successively through all the line, which brought them all into a state of readiness. The person at Mont Martre then received, letter by letter, the sentence from the Louvre, which he repeated with his own machine; and this was again repeated from the next height, with inconceivable rapidity, -to the final station at Lille.

The first description of the telegraph was brought from Paris to Frankfort on the Maine by a former member of the parliament of Bourdeaux, who had seen that which was erected on the mountain of Belville. As given by Dr Hutton from some of the English papers, it is as follows. AA is a beam or mast of wood placed upright on a rising ground (fig. i. Plate DIL), 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 cords. This balance is about ii or 12 feet long, and nine 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 three feet long, and may be placed either to the right or left, straight or square, with the balance-beam. By means of these three the combination of movement is 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 four seconds, the other 16 the machine is stationary. Two working models of this instrument were executed at Frankfort, and sent by Mr W. Playfair to the Duke of York; and hence the plan and alphabet of the machine came to England.

Various experiments were in consequence tried upon telegraphs in this country; and one was soon after let up by government in a chain of Nations from the admiralty office to the sea-coaft. It consists of six octagon boards, each of .which is poised upon an axis in a frame, in such a manner that it can be either placed vertically so as to appear with its full size to the observer at the nearest station, as in fig. 2. or it becomes invisible to him by being placed horizontally, as in fig, 3. so that the narrow edge alone is exposed, which .narrow edge is from a distance invisible. Fig. 2. is a representation of this telegraph, with the parts all shut, and the machine ready to work. T, in the officer's cabin, is the telescope pointed to the next station. Fig. 3. is a representation of the machine not at work, and with the ports all open. The .opening of the first port (fig. 2.) expresses a, the second b, the third c, the fourth d, the fifth e, and the sixth f, &c.

Six boards make 36 changes, by the most plain and simple mode of working; and they will make many more if .more were necessary: but as the real superiority or the telegraph over all other modes of making signals consists in its making letters, we do not think that more changes than the letters of the alphabet, and the ten arithmetical ciphers, are necessary; but, on the contrary, that those who work the .telegraphs should avoid communicating by words or signs agreed upon to express sentences; for that is the sure method never to become expert at lending unexpected intelligence accurately.

This telegraph is without doubt made up of the best number of combinations possible; five boards would be insufficient, and seven would be useless. It has been objected to it, however, that its form is too clumsy to admit of its being raised to any considerable height above the building on which it stands; and that it cannot be made to change its direction, and consequently cannot be seen but from one particular point.

Several other telegraphs have been proposed to remedy these defects, and perhaps others to which the instrument is still liable. The dial plate of a clock would make an excellent telegraph, as it might exhibit 144 signs so as to be visible at a great distance. A telegraph on this principle, with only six divisions instead of twelve, would be simple and cheap, and might be raised 20 or 30 feet high above the building without any difficulty; it might be supported on one post, and therefore turn round, and the contrast of colours would always be the same.

A very ingenious improvement of the telegraph has been , proposed in the Gentleman's Magazine. It consists of a semicircle, to be properly elevated, and fixed perpendicularly on a strong stand. The radius 12 feet; the semicircle consequently somewhat more than 36. This to be divided into 24 parts. Each of these will therefore comprise a space of 18 inches, and an arch of 7° 30' on the circumference. These 24 divisions to be occupied by as many circular apertures of fix inches diameter; which will leave a clear space of fix inches on each fide between the apertures. These apertures, beginning from the left, to denote the letters of trie alphabet, omitting K, J consonant, V, X, and Q as useless for this purpose. There are then 21 letters. The four other spaces are reserved for signals. The instrument to have an index moveable by a windlass on the centre of the semicircle, and having two tops, according as it is to be tiled in the day. or night; one, a circular top of lacquered iron or copper, of equal diameter with the apertures (and which consequently will eclipse any of them against which it rests); the other, a spear or arrow-shaped top, black, and highly-polished, which, in {landing before any of the apertures in the day-time, will be distinctly visible. In the night, the apertures to be reduced by a Diaphragm fitting close to each, so as to leave an aperture of not more than two inches diameter. The diaphragm to be of well polished tin; the inner rim lacquered black half an inch. All the apertures to be illuminated, when the instrument is used in the night time, by small lamps; to which, if necessary, according to circumstances, convex lenses may be added, fitted into each diaphragm, by which the light, may be powerfully concentrated and increased.- Over each aperture one of the five prismatic colours least likely to be mistaken (the remaining two being less distinguishable, and not wanted, are best omitted) to be painted; and, in their natural order, on a. width of eighteen inches and a depth of four red, orange, yellow, green, blue; or, still to heighten the contrast, and render immediately successive apertures more distinguishable, red, green, orange, blue, yellow. The whole inner circle beneath and between the apertures to be painted black.


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When the instrument is to be used, the index to be set to the signal apertures on the right. All the apertures to be covered or dark when it begins to be used, except that which is to give the signal. A signal gun to be fired to apprise the observer. If the index is set to the first aperture, it will denote that words are to be expressed; if to the second, that figures; if to the third, that the figures cease; and that the intelligence is carried on in words. When figures are to be expressed, the alternate apertures from the leit..are ..taken in their order, to denote from 1 to 10 inclusively the second from the right denotes 100; the fifth 1000. This Order, and these intervals, are taken to prevent any confusion in so peculiarly important an article of the intelligence to be conveyed.

Perhaps, however, none of the telegraphs hitherto offered to the public exceeds the following, either in simplicity, cheapness, or facility in working, and it might perhaps, with a few trifling additions, be made exceedingly distinct. It is thus described in the Reportory of Arts and Manufactures: For a nocturnal telegraph, let there be four large patent reflectors, lying on the same plane, parallel to the horizon, placed on the top of an observatory. Let each of these reflectors be capable, by means of two winches, either of elevation or depression to a certain degree. By elevating or depressing one or two of the reflectors, eighteen very distinct arrangements may be produced, as the following scheme will explain(A):

For the sake of example the above arrangements are made to answer to the most necessary letters of the alphabet; but alterations may be made at will, and a greater number of changes produced, without any addition to the reflectors. In the first observatory there need only be a set of single reflectors, but in the others each reflector should be double, so as to face both the preceding and subsequent observatory; and each observatory should be furnished with two telescopes. The proper diameter of the reflectors, and their distance from each other, will be ascertained by experience.

To convert this machine into a diurnal telegraph, nothing more is necessary than to insert, in the place of the reflectors, gilt balls, or any other conspicuous bodies.

Were telegraphs brought to so great a degree of perfection, that they could convey information speedily and distinctly; were they so much simplified, that they could be constructed and maintained at little expence--the advantages which would result from their use are almost inconceivable. Not to speak of the speed with which information could be communicated and orders given in time of war, by means of which misfortunes might be prevented or instantly repaired, difficulties removed, and disputes precluded, and by means of which the whole kingdom could be prepared in an instant to oppose an invading enemy; it might be used by commercial men to convey a commission cheaper and speedier than an express can travel. The capitals of distant nations might be united by chains of polls, and the settling of those disputes which at present take up months or years might then be accomplished in as many hours. An establishment of telegraphs might then be made like that of the post; and instead of being an expense, it would produce a revenue. Until telegraphs are employed to convey information that occurs very frequently, the persons who are stationed to work them will never become expert, and consequently will neither be expeditious nor accurate, though, with practice, there is no doubt but they will attain both in a degree of perfection of which we can at yet have but little conception.



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