THE HISTORY OF THE ELECTRIC TELEGRAPH.
[Footnote: Aug. Guerout in La Lurmière Electrique.]
An endeavor has often been made to carry the origin of the electric telegraph back to a very remote epoch by a reliance on those more or less fanciful descriptions of modes of communication based upon the properties of the magnet.
It will prove not without interest before entering into the real history of the telegraph to pass in review the various documents that relate to the subject.
In continuation of the 21st chapter of his Magia naturalis, published in 1553, J. B. Porta cites an experiment that had been made with the magnet as a means of telegraphing. In 1616, Famiano Strada, in his Prolusiones Academicæ, takes up this idea, and speaks of the possibility of two persons communicating by the aid of two magnetized needles influenced by each other at a distance. Galileo, in Dialogo intorno, written between 1621 and 1632 and Nicolas Caboeus, of Ferrara, in his Philosophia magnetica, both reproduce analogous descriptions, not however without raising doubts as to the possibility of such a system.
A document of the same kind, to which great importance has been attached is found in the Recreations mathematiques published at Rouen in 1628, under the pseudonym of Van Elten, and reprinted several times since, with the annotations and additions of Mydorge and Hamion and which must, it appears, be attributed to the Jesuit Leurechon. In his chapter on the magnet and the needles that are rubbed therewith, we find the following passage.
"Some have pretended that, by means of a magnet or other like stone, absent persons might speak with one another. For example, Claude being at Paris, and John at Rome, if each had a needle that had been rubbed with some stone, and whose virtue was such that in measure as one needle moved at Paris the other would move just the same at Rome, and if Claude and John each had an alphabet, and had agreed that they would converse with each other every afternoon at 6 o'clock, and the needle having made three and a half revolutions as a signal that Claude, and no other, wished to speak to John, then Claude wishing to say to him that the king is at Paris would cause his needle to move, and stop at T, then at H, then at E, then at K, I, N, G and so on. Now, at the same time, John's needle, according with Claude's, would begin to move and then stop at the same letters, and consequently it would be easily able to write or understand what the other desired to signify to it. The invention is beautiful, but I do not think there can be found in the world a magnet that has such a virtue. Neither is the thing expedient, for treason would be too frequent and too covert."
The same idea was also indicated by Joseph Glanville in his Scepsis scientifica, which appeared in 1665, by Father Le Brun, in his Histoire critique des pratiques superstitieuses, and finally by the Abbé Barthelemy in 1788.
The suggestion offered by Father Kircher, in his Magnes sive de arte magnetica, is a little different from the preceding. The celebrated Jesuit father seeks however, to do nothing more than to effect a communication of thoughts between two rooms in the same building. He places, at short distances from each other, two spherical vessels carrying on their circumference the letters of the alphabet, and each having suspended within it, from a vertical wire a magnetized figure. If one of these latter he moved, all the others must follow its motions, one after the other, and transmission will thus be effected from the first vessel to the last. Father Kircher observes that it is necessary that all the magnets shall be of the same strength, and that there shall be a large number of them, which is something not within the reach of everybody. This is why he points out another mode of transmitting thought, and one which consists in supporting the figures upon vertical revolving cylinders set in motion by one and the same cord hidden with in the walls.
There is no need of very thoroughly examining all such systems of magnetic telegraphy to understand that it was never possible for them to have a practical reality, and that they were pure speculations which it is erroneous to consider as the first ideas of the electric telegraph.
We shall make a like reserve with regard to certain apparatus that have really existed, but that have been wrongly viewed as electric telegraphs. Such are those of Comus and of Alexandre. The first of these is indicated in a letter from Diderot to Mlle. Voland, dated July 12, 1762. It consisted of two dials whose hands followed each other at a distance, without the apparent aid of any external agent. The fact that Comus published some interesting researches on electricity in the Journal de Physique has been taken as a basis for the assertion that his apparatus was a sort of electrical discharge telegraph in which the communication between the two dials was made by insulated wires hidden in the walls. But, if it be reflected how difficult it would have been at that epoch to realize an apparatus of this kind, if it be remembered that Comus, despite his researches on electricity, was in reality only a professor of physics to amuse, and if the fact be recalled that cabinets of physics in those days were filled with ingenious apparatus in which the surprising effects were produced by skillfully concealed magnets, we shall rather be led to class among such apparatus the so-called "Comus electric telegraph."
We find, moreover, in Guyot's Recreations physiques et mathematiques--a work whose first edition dates back to the time at which Comus was exhibiting his apparatus--a description of certain communicating dials that seem to be no other than those of the celebrated physicist, and which at all events enables us to understand how they worked.
Let one imagine to himself two contiguous chambers behind which ran one and the same corridor. In each chamber, against the partition that separated it from the corridor, there was a small bracket, and upon the latter, and very near the wall, there was a wooden dial supported on a standard, but in no wise permanently fixed upon the bracket. Each dial carried a needle, and each circumference was inscribed with twenty-five letters of the alphabet. The experiment that was performed with these dials consisted in placing the needle upon a letter in one of the chambers, when the needle of the other dial stopped at the same letter, thus making it possible to transmit words and even sentences. As for the means of communication between the two apparatus, that was very simple: One of the two dials always served as a transmitter, and the other as a receiver. The needle of the transmitter carried along in its motion a pretty powerful magnet, which was concealed in the dial, and which reacted through the partition upon a very light magnetized needle that followed its motions, and indicated upon an auxiliary dial, to a person hidden in the corridor, the letter on which the first needle had been placed. This person at once stepped over to the partition corresponding to the receiver, where another auxiliary dial permitted him to properly direct at a distance the very movable needle of the receiver. Everything depended, as will be seen, upon the use of the magnet, and upon a deceit that perfectly accorded with Comus' profession. There is, then, little thought in our opinion that if the latter's apparatus was not exactly the one Guyot describes, it was based upon some analogous artifice.
Jean Alexandre's telegraph appears to have borne much analogy with Comus'. Its inventor operated it in 1802 before the prefect of Indre-et-Loire. As a consequence of a report addressed by the prefect of Vienne to Chaptal, and in which, moreover, the apparatus in question was compared to Comus', Alexandre was ordered to Paris. There he refused to explain upon what principle his invention was based, and declared that he would confide his secret only to the First Consul. But Bonaparte, little disposed to occupy himself with such an affair, charged Delambre to examine it and address a report to him. The illustrious astronomer, despite the persistence with which Alexandre refused to give up his secret to him, drew a report, the few following extracts from which will, we think, suffice to edify the reader:
"The pieces that the First Consul charged me to examine did not contain enough of detail to justify an opinion. Citizen Beauvais (friend and associate of Alexandre) knows the inventor's secret, but has promised him to communicate it to no one except the First Consul. This circumstance might enable me to dispense with any report; for how judge of a machine that one has not seen and does not know the agent of? All that is known is that the telegraphe intime consists of two like boxes, each carrying a dial on whose circumference are marked the letters of the alphabet. By means of a winch, the needle of one dial is carried to all the letters that one has need to use, and at the same instant the needle of the second box repeats, in the same order, all the motions and indications of the first.
"When these two boxes are placed in two separate apartments, two persons can write to and answer one another, without seeing or being seen by one another, and without any one suspecting their correspondence. Neither night nor fog can prevent the transmission of a dispatch.... The inventor has made two experiments--one at Portiers and the other at Tours--in the presence of the prefects and mayors, and the record shows that they were fully successful. To-day, the inventor and his associate ask that the First Consul be pleased to permit one of the boxes to be placed in his apartment and the other at the house of Consul Cambaceres in order to give the experiment all the éclat and authenticity possible; or that the First Consul accord a ten minutes' interview to citizen Beauvais, who will communicate to him the secret, which is so easy that the simple expose of it would be equivalent to a demonstration, and would take the place of an experiment.... If, as one might be tempted to believe from a comparison with a bell arrangement, the means adopted by the inventor consisted in wheels, movements, and transmitting pieces, the invention would be none the less astonishing.... If, on the contrary, as the Portier's account seems to prove, the means of communication is a fluid, there would be the more merit in his having mastered it to such a point as to produce so regular and so infallible effects at such distances.... But citizen Beauvais ... desires principally to have the First Consul as a witness and appreciator.... It is to be desired, then, that the First Consul shall consent to hear him, and that he may find in the communication that will be made to him reasons for giving the invention a good reception and for properly rewarding the inventor."
But Bonaparte remained deaf, and Alexandre persisted in his silence, and died at Angers, in 1832, in great poverty, without having revealed his secret.
As, in 1802, Volta's pile was already invented, several authors have supposed an application of it in Alexandre's apparatus. "Is it not allowable to believe," exclaims one of these, "that the electric telegraph was at that time discovered?" We do not hesitate to respond in the negative. The pile had been invented for too short a time, and too little was then known of the properties of the current, to allow a man so destitute of scientific knowledge to so quickly invent all the electrical parts necessary for the synchronic operation of the two needles. In this telegraphe intime we can only see an apparatus analogous to the one described by Guyot, or rather a synchronism obtained by means of cords, as in Kircher's arrangement. The fact that Alexandre's two dials were placed on two different stories, and distant, horizontally, fifteen meters, in nowise excludes this latter mode of transmission. On another hand, the mystery in which Alexandre was shrouded, his declaration relative to the use of a fluid, and the assurance with which he promised to reveal his secret to the First Consul, prove absolutely nothing, for too often have the most profoundly ignorant people--the electric girl, for example--befooled learned bodies by the aid of the grossest frauds. From the standpoint of the history of the electric telegraph, there is no value, then, to be attributed to this apparatus of Alexandre, any more than there is to that of Comus or to any of the dreams based upon the properties of the magnet.
The history of the electric telegraph really begins with 1753, the date at which is found the first indication of a telegraph truly based upon the use of electricity. This telegraph is described in a letter written by Renfrew, dated Feb. 1, 1753, and signed with the initials "C.M.," which, in all probability, were those of a savant of the time--Charles Marshall. A few extracts from this letter will give an idea of the precision with which the author described his invention:
"Let us suppose a bundle of wires, in number equal to that of the letters of the alphabet, stretched horizontally between two given places, parallel with each other and distant from each other one inch.
"Let us admit that after every twenty yards the wires are connected to a solid body by a juncture of glass or jeweler's cement, so as to prevent their coming in contact with the earth or any conducting body, and so as to help them to carry their own weight. The electric battery will be placed at right angles to one of the extremities of the wires, and the bundle of wires at each extremity will be carried by a solid piece of glass. The portions of the wires that run from the glass support to the machine have sufficient elasticity and stiffness to return to their primitive position after having been brought into contact with the battery. Very near to this same glass support, on the opposite side, there descends a ball suspended from each wire, and at a sixth or a tenth of an inch beneath each ball there is placed one of the letters of the alphabet written upon small pieces of paper or other substance light enough to be attracted and raised by the electrified ball. Besides this, all necessary arrangements are taken so that each of these little papers shall resume its place when the ball ceases to attract.
FIG. 1.--LESAGE'S TELEGRAPH.
"All being arranged as above, and the minute at which the correspondence is to begin having been fixed upon beforehand, I begin the conversation with my friend at a distance in this way: I set the electric machine in motion, and, if the word that I wish to transcribe is 'Sir,' for example, I take, with a glass rod, or with any other body electric through itself or insulating, the different ends of the wires corresponding to the three letters that compose the word. Then I press them in such a way as to put them in contact with the battery. At the same instant, my correspondent sees these different letters carried in the same order toward the electrified balls at the other extremity of the wires. I continue to thus spell the words as long as I judge proper, and my correspondent, that he may not forget them, writes down the letters in measure as they rise. He then unites them and reads the dispatch as often as he pleases. At a given signal, or when I desire it, I stop the machine, and, taking a pen, write down what my friend sends me from the other end of the line."
The author of this letter points out, besides, the possibility of keeping, in the first place, all the springs in contact with the battery, and, consequently, all the letters attracted, and of indicating each letter by removing its wire from the battery, and consequently making it fall. He even proposed to substitute bells of different sounds for the balls, and to produce electric sparks upon them. The sound produced by the spark would vary according to the bell, and the letters might thus be heard.
Nothing, however, in this document authorizes the belief that Charles Marshall ever realized his idea, so we must proceed to 1774 to find Lesage, of Geneva, constructing a telegraph that was based upon the principle indicated twenty years before in the letter of Renfrew.
The apparatus that Lesage devised (Fig. 1) was composed of 24 wires insulated from one another by a non conducting material. Each of these wires corresponded to a small pith ball suspended by a thread. On putting an electric machine in communication with such or such a one of these wires, the ball of the corresponding electrometer was repelled, and the motion signaled the letter that it was desired to transmit. Not content with having realized an electric telegraph upon a small scale, Lesage thought of applying it to longer distances.
"Let us conceive," said he in a letter written June 22, 1782, to Mr. Prevost, of Geneva, "a subterranean pipe of enameled clay, whose cavity at about every six feet is separated by partitions of the same material, or of glass, containing twenty-four apertures in order to give passage to as many brass wires as these diaphragms are to sustain and keep separated. At each extremity of this pipe are twenty-four wires that deviate from one another horizontally, and that are arranged like the keys of a clavichord; and, above this row of wire ends, are distinctly traced the twenty-four letters of the alphabet, while beneath there is a table covered with twenty-four small pieces of gold-leaf or other easily attractable and quite visible bodies."
Lesage had thought of offering his secret to Frederick the Great; but he did not do so, however, and his telegraph remained in the state of a curious cabinet experiment. He had, nevertheless, opened the way, and, dating from that epoch, we meet with a certain number of attempts at electrostatic telegraphy. [1]
[Footnote 1: Advantage has been taken of a letter from Alexander Volta to Prof. Barletti (dated 1777), indicating the possibility of firing his electric pistol from a great distance, to attribute to him a part in the invention of the telegraph. We have not shared in this opinion, which appears to us erroneous, since Volta, while indicating the possibility above stated, does not speak of applying such a fact to telegraphy.]
The first in date is that of Lemond, which is spoken of by Arthur Young (October 16, 1787), in his Voyage Agronomique en France:
"In the evening," says he, "we are going to Mr. Lemond's, a very ingenious mechanician, and one who has a genius for invention.... He has made a remarkable discovery in electricity. You write two or three words upon paper; he takes them with him into a room and revolves a machine within a sheath at the top of which there is an electrometer--a pretty little ball of feather pith. A brass wire is joined to a similar cylinder, and electrified in a distant apartment, and his wife on remarking the motions of the ball that corresponds, writes down the words that they indicate; from whence it appears that he has formed an alphabet of motions. As the length of the wire makes no difference in the effect, a correspondence might be kept up from very far off, for example with a besieged city, or for objects much more worthy of attention. Whatever be the use that shall be made of it, the discovery is an admirable one."
And, in fact, Lemond's telegraph was of the most interesting character, for it was a single wire one, and we already find here an alphabet based upon the combination of a few elementary signals.
The apparatus that next succeeds is the electric telegraph that Reveroni Saint Cyr proposed in 1790, to announce lottery numbers, but as to the construction of which we have no details. In 1794 Reusser, a German, made a proposition a little different from the preceding systems, and which is contained in the Magazin für das Neueste aus der Physik und Naturgeschichte, published by Henri Voigt.
"I am at home," says Reusser, "before my electric machine, and I am dictating to some one on the other side of the street a complete letter that he is writing himself. On an ordinary table there is fixed vertically a square board in which is inserted a pane of glass. To this glass are glued strips of tinfoil cut out in such a way that the spark shall be visible. Each strip is designated by a letter of the alphabet, and from each of them starts a long wire. These wires are inclosed in glass tubes which pass underground and run to the place whither the dispatch is to be transmitted. The extremities of the wires reach a similar plate of glass, which is likewise affixed to a table and carries strips of tinfoil similar to the others. These strips are also designated, by the same letters, and are connected by a return wire with the table of him who wishes to dictate the message. If, now, he who is dictating puts the external armature of a Leyden jar in contact with the return wire, and the ball of this jar in contact with a metallic rod touching that of the tinfoil strip which corresponds with the letter which he wishes to dictate to the other, sparks will be produced upon the nearest as well as upon the remotest strips, and the distant correspondent, seeing such sparks, may immediately write down the letter marked. Will an extended application of this system ever be made? That is not the question; it is possible. It will be very expensive; but the post hordes from Saint Petersburg to Lisbon are also very expensive, and if any one should apply the idea on a large scale, I shall claim a recompense."
Every letter, then, was signaled by one or several sparks that started forth on the breaking of the strip; but we see nothing in this document to authorize the opinion which has existed, that every tinfoil strip was a sort of magic tablet upon which the sparks traced the very form of the letter to be transmitted.
Voigt, the editor of the Magazin, adds, in continuation of Reusser's communication: "Mr. Reusser should have proposed the addition to this arrangement of a vessel filled with detonating gas which could be exploded in the first place, by means of the electric spark, in order to notify the one to whom something was to be dictated that he should direct his attention to the strips of tinfoil."
This passage gives the first indication of the use of a special call for the telegraph. The same year (1794), in a work entitled Versuch über Telegraphie und Telegraphen, Boeckmann likewise proposed the use of the pistol as a call signal, in conjunction with the use of a line composed of two wires only, and of discharges in the air or a vacuum, grouped in such a way as to form an alphabet.
Experiments like those indicated by Boeckmann, however, seem to have been made previous to 1794, or at that epoch, at least, by Cavallo, since the latter describes them in a Treatise on Electricity written in English, and a French translation of which was published in 1795. In these experiments the length of the wires reached 250 English feet. Cavallo likewise proposed to use as signals combustible or detonating materials, and to employ as a call the noise made by the discharge of a Leyden jar.
In 1796 occurred the experiments of Dr. Francisco Salva and of the Infante D. Antonio. The following is what we may read on this subject in the Journal des Sciences:
"Prince de la Paix, having learned that Dr. Francisco Salva had read before the Royal Academy of Sciences of Barcelona a memoir on the application of electricity to telegraphy, and that he had presented at the same time an electric telegraph of his own invention, desired to examine this machine in person. Satisfied as to the accuracy and celerity with which we can converse with another by means of it, he obtained for the inventor the honor of appearing before the king. Prince de la Paix, in the presence of their majesties and of several lords, caused the telegraph to converse to the satisfaction of the whole court. The telegraph conversed some days afterward at the residence of the Infante D. Antonio.
"His Highness expressed a desire to have a much completer one that should have sufficient electrical power to communicate at great distances on land and sea. The Infante therefore ordered the construction of an electric machine whose plate should be more than forty inches in diameter. With the aid of this machine His Highness intends to undertake a series of useful and curious experiments that he has proposed to Dr. D. Salva."
In 1797 or '98 (some authors say 1787), the Frenchman, Betancourt, put up a line between Aranjuez and Madrid, and telegraphed through the medium of discharges from a Leyden jar.
But the most interesting of the telegraphs based upon the use of static electricity is without doubt that of Francis Ronalds, described by the latter, in 1823, in a pamphlet entitled Descriptions of an Electrical Telegraph and of some other Electrical Apparatus, but the construction of which dates back to 1816.
What is peculiarly interesting in Ronalds' apparatus is that it presents for the first time the use of two synchronous movements at the two stations in correspondence.
The apparatus is represented in Fig. 2. It is based upon the simultaneous working of two pith-ball electrometers, combined with the synchronous running of two clock-work movements. At the two stations there were identical clocks for whose second hand there had been substituted a cardboard disk (Fig. 3), divided into twenty sectors. Each of these latter contained one figure, one letter, and a conventional word. Before each movable disk there was a screen, A (Fig. 2), containing an aperture through which only one sector could, be seen at a time. Finally, before each screen there was a pith-ball electrometer. The two electrometers were connected together by means of a conductor (C) passing under the earth, and which at either of its extremities could be put in communication with either an electric machine or the ground. A lever handle, J, interposed into the circuit a Volta's pistol, F, that served as a call.
When one of the operators desired to send a dispatch to the other he connected the conductor with the machine, and, setting the latter in operation, discharged his correspondent's pistol as a signal. The call effected, the first operator continued to revolve the machine so that the balls of pith should diverge in the two electrometers. At the same time the two clocks were set running. When the sender saw the word "attention" pass before the slit in the screen he quickly discharged the line, the balls of the two electrometers approached each other, and, if the two clocks agreed perfectly, the correspondent necessarily saw in the aperture in his screen the same word, "attention." If not, he moved the screen in consequence, and the operation was performed over until he could send, in his turn, the word "ready." Afterward, the sender transmitted in the same way one of the three words, "letters," "figures," "dictionary," in order to indicate whether he wished to transmit letters or figures, or whether the letters received, instead of being taken in their true sense, were to be referred to a conventional vocabulary got up in advance. It was after such preliminaries that the actual transmission of the dispatch was begun. The pith balls, which were kept constantly apart, approached each other at the moment the letter to be transmitted passed before the aperture in the screen.
Ronalds, in his researches, busied himself most with the construction of lines. He put up on the grounds near his dwelling an air line 8 miles long; and, to do so, stretched fine iron wire in zigzag fashion between two frames 18 meters apart. Each of these frames carried thirty-seven hooks, to which the wire was attached through the intermedium of silk cords. He laid, besides, a subterranean line of 525 feet at a depth of 4 feet. The wire was inclosed within thick glass tubes which were placed in a trough of dry wood, of 2 inch section, coated internally and externally with pitch. This trough was, moreover, filled full of pitch and closed with a cover of wood. Ronalds preferred these subterranean conductors to air lines. A portion of one of them that was laid by him at Hammersmith figured at the Exhibition of 1881, and is shown in Fig. 4.
Nearly at the epoch at which Ronalds was experimenting in England, a certain Harrisson Gray Dyar was also occupying himself with electrostatic telegraphy in America. According to letters published only in 1872 by American journals, Dyar constructed the first telegraph in America. This line, which was put up on Long Island, was of iron wire strung on poles carrying glass insulators, and, upon it, Dyar operated with static electricity. Causing the spark to act upon a movable disk covered with litmus paper, he produced by the discoloration of the latter dots and dashes that formed an alphabet.
FIG. 2.
These experiments, it seems, were so successful that Dyar and his relatives resolved to construct a line from New York to Philadelphia; but quarrels with his copartners, lawsuits, and other causes obliged him to leave for Rhode Island, and finally for France in 1831. He did not return to America till 1858.
Dyar, then, would seem to have been the first who combined an alphabet composed of dots and dashes. On this point, priority has been claimed by Swaim in a book that appeared at Philadelphia in 1829 under the title of The Mural Diagraph, and in a communication inserted in the Comptes Rendus of the Academic des Sciences for Nov. 27, 1865.
FIG. 3.
In 1828, likewise, Victor Triboaillet de Saint Amand proposed to construct a telegraph line between Paris and Brussels. This line was to be a subterranean one, the wire being covered with gum shellac, then with silk, and finally with resin, and being last of all placed in glass tubes. A strong battery was to act at a distance upon an electroscope, and the dispatches were to be transmitted by the aid of a conventional vocabulary based upon the number of the electroscope's motions.
Finally, in 1844, Henry Highton took out a patent in England for a telegraph working through electricity of high tension, with the use of a single line wire. A paper unrolled regularly between two points, and each discharge made a small hole in it, But this hole was near one or the other of the points according as the line was positively or negatively charged. The combination of the holes thus traced upon two parallel lines permitted of the formation of an alphabet. This telegraph was tried successfully over a line ten miles long, on the London and Northwestern Railway.
FIG. 4.
We have followed electrostatic telegraphs up to an epoch at which telegraphy had already entered upon a more practical road, and it now remains for us to retrace our steps toward those apparatus that are based upon the use of the voltaic current.
Prof. Dolbear observes that if a galvanometer is placed between the terminals of a circuit of homogeneous iron wire and heat is applied, no electric effect will be observed; but if the structure of the wire is altered by alternate bending or twisting into a helix, then the galvanometer will indicate a current. The professor employs a helix connected with a battery, and surrounding a portion of the wire in circuit with the galvanometer. The current in the helix magnetizes the circuit wire inclosed, and the galvanometer exhibits the presence of electricity. The experiment helps to prove that magnetism is connected with some molecular change of the magnetized metal.