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From the North British Review.

THE ELECTRIC TELEGRAPH.*

THE seven wonders of the world have, passed into oblivion among the miracles of science which the present day has been permitted to witness. The inventions of former times, beautiful and useful as they have been, sink into insignificance beside those magnificent combinations of science and of art which every day excite our attention, and add to our happiness. The telescope and the microscope, the chronometer and the compass, and various other instruments which society has long possessed, however much they have contributed to the advancement of science, and to individual and general interests, can scarcely be ranked among those grand inventions which ameliorate the social condition of all the races of mankind, which change the very habits of social life, and add to the physical and intellectual enjoyments of every inhabitant of the globe. The steamengine, with its application to navigation, locomotion, and every species of labor once cruelly exacted from man and the lower animals, the electric light, rivalling the sun in brilliancy, the photographic art, by which invisible rays paint a portrait or a landscape, with unerring accuracy, the lighting of our houses and streets by a gaseous element transmissible like water through pipes,- the electric telegraph, which despatches its messages of lightning over the wire- girdled globe, are the great inventions which have sprung up during the life of men still alive, and which display those transcendent powers which have been given to man for the benefit of his race.

But while man has nobly executed the task which the Almighty has committed to his genius, we must not forget that it is to the elements themselves which he has subjugated to his will, and to the materials provided for

* 1. The_Museum of Science and Art. Edited by DIONYSIUS LARDNER, D.C.L. On the Electric Telegraph.

Vol. III. and IV.

2. Mémoire de la Telegraphie Electrique. Par M. WERNER SIEMENS, (de Berlin,) Ancien Officer D'Artillerie. Paris, 1850. Pp. 48.

3. Reports by the Juries of the Great Exhibition. Report of Jury X. London, 1850.

him by his Creator's hand, that society is indebted for the gift they enjoy. The heat, the light, the electric fluid-the great cosmical principles which enliven and enchain the universe, have been the prime ministers of the philosopher, while the coal, the metals, and the water raised to his level from the depths of the earth, have been his bumbler agents.

We should require to write the history of science, were we to record the steps of discovery by which the physical laws have been established upon which these inventions depend, and to associate with each step the immortal name by which it was achieved. It is in records little known, and as little appreciated, that such names appear. It is to those who have applied the discoveries to practical use, that the prize of popular and successful invention is adjudged, and it is round their brow that the laurel of contemporary fame is entwined. The names of Oersted, Arago, and Schweigger, without whose discoveries the present electric telegraph would never have existed, are rarely pronounced even in union with those of the mechanical inventors who have been enriched by their labors.

In enumerating the wonders of the past and the passing age, we have omitted the greatest of them all. There is no principle stronger in our nature than that which prompts us to the reciprocity of kindness. Gratitude is one of the cheapest of virtues. To feel and to express it, is, in our individual capacities, to discharge the duty which we owe to a benefactor. It is different, however, with nations. The gifts which the philosopher confers upon his race can be rewarded only by the community to which he belongs. There is no cosmical legislature to take cognizance of the world's benefactors, and the principle of philanthropy combines itself with the patriotic impulse in stimulating Governments to the remuneration of national service. Is it not then the greatest wonder in the world, the most astounding truth with which we have to deal, and with which feel

ing has to struggle, that not one of the great men to whom the world owes the gigantic inventions we have enumerated, have ever received any of those marks of honor, which the selfish statesman takes to himself, and gives to his accomplices;-which characterize the diplomatic juggler, and which shine on the breast of the human hyæna who has risked a useless life in the battle-field of unjust and aggressive war?

In an article like the present, and within so limited a space, it will be difficult to convey, without diagrams, a distinct idea of the various inventions which are combined in the construction and use of the Electric Telegraph, but with a little attention on the part of the reader, this difficulty may to a certain extent be surmounted, and we hope to be able to give an intelligible idea of the general apparatus and arrangements by which this noble art has been brought to such high and unexpected perfection.

The word Telegraph, which means to write at a distance, has been long in use, as the name of a very imperfect system of communicating intelligence by signals, which was used by the ancients, and is at present employed, under very rude forms, even among savage nations. In modern times the art has been brought to great perfection, and was in general use in this country and on the continent during the last European war; but it has been entirely abandoned since the invention of the Electric Telegraph. Between Plymouth and the Admiralty in London, for example, various signal stations were lished, and the messages sent from Plymouth passed from station to station till they reached the Admiralty. During the night the signals were of course luminous; but neither these nor day signals were visible in fogs, so that for whole days no telegraphic message could be conveyed. At the time of the peninsular war a very remarkable effect was produced, in consequence of a fog coming on during the transmission of a message from the seat of war to the admiral commanding at Plymouth. The words which reached the Admiralty were, "Wellington defeated. The ominous sentence arrived in the morning, and occasioned great anxiety till a clear afternoon brought up the other two cheering words, "The Enemy, &c., &c."

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The first important step to the invention of the Electric Telegraph was made upwards of an hundred years ago by M. Le Monnier in France, and Sir William Watson in England. Le Monnier caused the electric shock to pass through an iron wire nearly 6,000 feet in

length, and found that it moved through that space in less than a quarter of a second. He then electrified a wire 1,319 feet long, and he found that the electricity ceased at one end the moment the electricity was taken off at the other. Sir William Watson's experiments were made on a greater scale, and led to still more important results. On the 14th August 1747, he stretched a wire 6,732 feet long over Shooter's Hill, and supported it upon rods of baked wood. This wire communicated with the iron rod which was to make the discharge. Another wire communicating with a charged Leyden jar was 3,868 feet long. The distance between the observers was about two miles, and as two miles of dry ground formed part of the circuit, its length was upwards of four miles. When the shock was made to pass through this space, no time appeared to elapse during its passage, and the observers considered it as instantaneous. In another experiment, when the wire was 12,276 feet long, the very same result was obtained.

Although it was thus placed beyond a doubt that electricity passed instantaneously, or in a time too short to admit of being measured, no application of this valuable fact seems to have been made by the philosophers who were assembled at Shooter's Hill. It was reserved for a Scotchman, a gentleman residing at Renfrew, to suggest the idea of transmitting messages by electricity along wires passing from one place to another. This remarkable proposal was pubestablished in the Scots Magazine for February 1753, in an article bearing the initials C. M., the only name which we shall probably ever obtain for the first inventor of the Electric Telegraph.* This letter, entitled "An expeditious Method of Conveying Intelligence, is so interesting, that we shall lay the whole of it before our readers.

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* When the writer of this article first perused this remarkable document, he sent it to the Commonwealth, an ably-conducted Glasgow paper, in the hope that a real name might still be found to replace the initials C. M.

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about an inch distant from that next to it. At every twenty yards' end let them be fixed on glass with jewellers' cement to some firm body, both to prevent them from touching the earth, or any other non-electric, and from breaking by their own gravity. Let the electric gun barrel be placed at right angles with the extremities of the wire, and about an inch below them. Also, let the wires be fixed in a solid piece of glass six inches from the end, and let all that part of them which reaches from the glass to the machine have sufficient spring and stiffness to recover its situation after being brought in contact with the barrel. Close by the supporting glass let a ball be suspended from every wire, and about a sixth or an eighth of an inch below the balls, place the letters of the alphabet marked on bits of paper, or any other substance that may be light enough to rise to the electrified ball, and at the same time let it be so contrived that each of them may reassume its proper place when dropt. All things constructed as above, and the minute previously fixed, I begin the conversation with my dis. tant friend in this manner. Having set the electrical machine agoing as in ordinary experiments, suppose I am to pronounce the word Sir, with a piece of glass or any other electric per se, I strike the wire S so as to bring it in contact with the barrel, then i, then r, all in the same way, and my correspondent almost in the same instant observes those several characters rise in order to the electrified balls at his end of the wires. Thus I spell away as long as I think fit, and my correspondent, for the sake of memory, writes the characters as they rise, and may join and read them afterwards as often as he inclines. Upon a signal given or from choice I stop the machine, and taking up the pen in my turn, I write down at the other end whatever my friend strikes out.

"If any body should think this way tiresome, let him, instead of the balls, suspend a range of bells from the roof equal in number to the letters of the alphabet, gradually decreasing in size from the Bell A to Z, and from the horizontal wires let there be another set reaching to the several bells, one, viz., from the horizontal wire A to the Bell A, another from the horizontal wire B to the bell B, &c. Then let him who begins the discourse bring the wire in contact with the barrel as before; and the electrical spark working on bells of different sizes, will inform the correspondent by the sound what wires have been touched. And thus by some practice they may come to understand the lan

guage of the chimes in whole words, without being put to the trouble of noting down every letter.

"The same thing may be otherwise effected. Let the balls be suspended over the characters as before, but instead of bringing the ends of the horizontal wires in contact with the barrel, let a second set reach from the electrified cask (barrel) so as to be in contact with the horizontal ones; and let it be so contrived at the same time, that any of them may be removed from its corresponding horizontal by the slightest touch, and may bring itself again into contact when left at liberty. This may be done by the help of a small spring and slider, or twenty other methods, which the least ingenuity will discover. In this way the characters will always adhere to the balls, excepting when any one of the secondaries is removed from contact with its horizontal, and then the letter at the other end of the horizontal will immediately drop from its ball. But I mention this only by way of variety.

Some may perhaps think, that although the electric fire has not been observed to diminish sensibly in its progress through any length of wire that has been tried hitherto, yet as that has never exceeded thirty or forty yards, it may be readily supposed that in a far greater length it would be remarkably diminished, and probably would be entirely drained off in a few miles by the surrounding air. To prevent the objection, and save longer argument, lay over the wires from one end to the other with a thin coat of jeweller's cement. This may be done for a trifle of additional expense; and as it is an electric per se, will effectually secure any part of the fire from mixing with the atmosphere.-I am, &c., C. M."

Here we have an electric telegraph upwards of a hundred years old, which at the present day would convey intelligence expedi tiously, and we are constrained to admit that C. M. was the true inventor of the electric telegraph, and that every step made since that time, however sagacious and valuable, can be viewed in no other light than an improvement. It is singular that the ingenious author should not have adopted some of the obvious modes for diminishing the number of wires; but as he seems to have had no expectation of his invention being adopted, he probably contented himself with a general view of the principle.

The Author was obviously ignorant of Sir. W. Watson's experiments.

Twenty-one years after this invention was published, in the year 1774, M. Lesage of Geneva is said to have established a telegraph there, which, in so far as it has been described, is precisely the same as that of our countryman C. M. It had twenty-four wires imbedded in an insulating material, with a pith ball electrometer attached to each wire, the motion of which indicated the letters of the alphabet.

When our countryman Arthur Young was in France in 1787, he either saw or heard of an electric telegraph which he thus describes: "M. Lamond has made a remarkable discovery in electricity. You write two or three words upon paper. He takes them with him into a room, and turns an electrical machine, above which is an electrometer with a little ball made of the pith of a feather. A copper wire is joined to a similar electrical machine in a distant apartment, and his wife, on observing the movement of the corresponding ball, writes the words which it indicates, from which it appears that he has constructed an alphabet of motion. As the length of the copper wire makes no difference on the effect, a correspondence might be maintained at a great distance; for example, at a besieged town, or for purposes much more worthy of attention, and a thousand times more innocent." It is obvious from this description that the different letters of the alphabet must have been indicated by different numbers of displacements of the pith ball, making one wire the tedious narrator of the message.

In 1787, M. Betancourt, a French engineer, established telegraphic wires between Aranjuez and Madrid, and transmitted messages by successive electric discharges from a Leyden jar. Cavallo, in 1795, proposed to transmit signals along wires by the inflammation of several combustible or detonating substances, such as gunpowder, phosphorus, and phosphorated hydrogen, or by means of simple electrical sparks given out by the wire.

An important step was made in telegraphic apparatus by Mr. Francis Ronalds. Previous to 1823, he constructed a telegraph on his lawn at Hammersmith, by insulating eight miles of wire with silk strings. He made the same experiments with 525 feet of bronzed wire. The wire was laid in a trough of wood two inches square, well lined both within and without with pitch, and inside the trough were placed thick glass tubes through which the wire ran. The joints of the glass tubes were surrounded with short and wider tubes of glass, the ends of which were sealed up

with soft wax. The wooden trough was then placed in a trench four feet deep. An ingenious apparatus, with a dial containing letters and figures, was fixed upon the seconds arbor of a clock, which beat dead seconds, and another in front of it with an aperture and an electrometer, so that the collapsing and diverging of the pith ball corresponded with the letter or number on the dial, as seen through the aperture of the plate in front of it.

In all these contrivances, ordinary or statical electricity, such as is produced by friction in electrical machines, was employed; and if no other form of the electric force had been discovered, it is obvious, from the preceding inventions, that we should have had at this day a real working electric telegraph, not so simple, nor with so many resources, but still an instrument which would have amply fulfilled the grand object of communicating intelligence with the speed of lightning. A new source of electric power, what has been called dynamic electricity, however, was discovered by Volta in 1800, and became the agent in various new forms of the electric telegraph. If we take a disc of copper like a penny piece, and another of zinc of the same size, and placing one above the tongue, and the other below it, make them touch at or below the tip of the tongue, we shall feel a sharp taste which disappears as soon as the discs are freed from contact. If we now join these two discs with a piece of wire soldered to each, and place them in a glass or stone ware vessel of salt water, or water made acid with nitric, muriatic, or sulphuric acid, the water will be decomposed, and a current of electricity will flow from the zinc disc, which is the positive end, to the copper disc, which is the negative end of this little galvanic battery, as it may be called. When a number of these vessels, with their united discs of copper and zinc, are placed in a row, so that the zinc of one vessel is connected by a wire with the copper of another, we have a large and powerful battery, capable of giving severe shocks, and causing combustion, light, and chemical decomposition. In order that this battery may produce any of these effects, one wire passes from the last copper disc at one end, and termintes in a point A, while another wire passes from the last zinc disc at the other end, and terminates in a point B, A and B representing the ends of the wires. When the extremities A and B are in contact, or if the wire has no break at these points, the current of electricity would have

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passed from B to A, but when the current is interrupted, and bodies are placed between A and B, the current forces its way through them, turning and decomposing them, and producing sparks and shocks when the current passes through the human body, or any part of it. The electric force may be obtained by placing the zinc and copper discs in a pile above one another, and separating them by discs of cloth wetted with acidulated water. In this form it is called the Pile of Volta.

The first application of this new power to telegraphic purposes was made by M. Som mering of Munich in 1811, and by means of a very ingenious contrivance. Upon the bottom of a glass vessel he fixed thirty-five points of gold, indicating thirty-five letters, and ten numerals from 0 to 9. From each of these thirty-five points there passed a copper conductor terminating in a small brass cylinder, in the middle of which was a groove for receiving a small screw nut for fixing the wires which united the corresponding point with the positive or negative pole of the battery or pile which he used. When the glass vessel was filled with water, and the electricity communicated to the letter at one end of a wire, the gold point coresponding to this letter gave out a bubble of gas, which was largest when it was oxygen and smallest when it was hydrogen, so that he could transmit two letters at once. Sommering covered each of his thirty-five wires with silk, and surrounded the whole with varnish. Our limits will not permit us to describe this beautiful invention more particularly, but it is obviously one capable of doing real telegraphic work, and wanted only what he added afterwards, a contrivance or alarm, for calling the attention of the operator at the distant station. Like C. M. the Bavarian mechanician never seems to have thought of reducing the number of his wires by different combinations of his gas bubbles, as afterwards suggested by Schweigger, who proposed the detonating pistol of Volta as an alarm.

The grand discovery of electro-magnetism by Professor Oersted of Copenhagen, in 1819, led to great improvements in the construction and use of the electric telegraph. By placing a compass-needle parallel to the conducting wire of a Voltaic battery, that is, parallel to the current, he found that it placed itself across the current, or at right angles to the wire. When the current passed above the needle, its north pole deviated to the west, and the current came from south to north, and the same pole deviated to the east when the

current came from north to south. When the current passed below the needle the opposite effects were produced, the south pole being deviated to the east when the current passed from south to north, and to the west when it came from north to south. M. Ampere illustrated this in a very happy manner. He supposed a miniature figure of a man to be placed in a lying position along the conducting wire, with the feet towards the zinc pole, and the head towards the copper pole, so that the current passing from the zinc to the copper pole entered at the feet and came out at the head, the figure having its face turned to the middle of the needle, the effect of the current will be always to turn its south pole to the left hand of the figure. The electro-magnetic force thus exhibited, even when extremely feeble, may be augmented to almost any extent by the beautiful contrivance of Schweigger, called a multiplier. If one wire produced a perceptible action upon the needle, he concluded that the effect would increase with the amount of wire, and having coiled a wire upon itself fifty or an hundred times, he found the result such as he expected, provided none of the electricity escaped from one wire to those adjacent to it. To prevent this or to insulate the wires, he covered each of them with a silken thread coiled so closely as to cover their surface completely. These multipliers have been made so powerful that they required a wire three miles and a half long.

In 1820, M. Ampere was led to prefer the substitution of a compass-needle in the electric telegraph in place of the gold points and gas bubbles of Semmering, so that by touching a number of keys corresponding to each letter of the alphabet, the needles at the other end of the twenty-five wires were put in motion. A telegraph of this description was actually made in Edinburgh by Mr. Alexander in 1837, in which thirty wires communicated with the same number of magnetic needles, and the instrument was wrought by touching thirty keys as in the telegraph of Sommering. Coupling this idea with that of Schweigger to reduce the twenty-five wires to two by means of two piles, we have obviously an electric telegraph of a very high order perfectly fitted to perform telegraphic work, though still susceptible of many improvements. But even if the most perfect electric telegraph of the present day had been then invented, no person would have thought of making use of it. It is to the railway system alone that we are

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