Lives of the electricians

In all the inventions and discoveries previously described as made by Professor Wheatstone, his originality has never been seriously challenged, but when we turn to his greatest work we enter upon contested ground. The contests that ever arise as to the origin of great inventions afford evidence of their greatness; for, as Aeschylus says, he who is not envied is not worthy of admiration.

“In 1435,” says Sir James Mackintosh, “a law suit was carried on at Strasburg between one John Guttenberg, a gentleman of Mentz, celebrated for mechanical ingenuity, and Drizehn, a burgher of the city, who was his partner in a copying press. No litigation could seem more base and mechanical to the barbarous Barons of Suabia and Alsace; but the copying machine was the printing press which has changed the condition of mankind.” In like manner it fell to the lot of Professor Wheatstone when he had completed his most useful invention to have his originality disputed by his own partner in business, Mr. William Fothergill Cooke. There are five mechanical inventions that have conferred incalculable benefit on the industrial world in modern times—the printing press, the steam engine, the electric telegraph, the dynamo, and the Bessemer process of steel making. The originality of every one of these has been either divided or disputed, with the single exception of the Bessemer process, which is therefore the only one that is universally known by the inventor’s name. In the case of the electric telegraph the originality or priority of Professor Wheatstone was disputed not only at home but abroad. Hence writers on the subject are accustomed to say that the telegraph was invented independently and almost simultaneously by Professor Wheatstone, of London, Professor Morse, of New York, and Professor Steinheil, of Munich. This was in the year 1837.

After the discovery of the voltaic pile, Oersted discovered in 1819 that if a needle were placed parallel to a conducting wire, an electric current from a voltaic battery applied to the wire would cause the deflection of the needle to a position at right angles to the wire or across the direction of the current. Ampère proposed to make an electric telegraph by utilising this property of a compass needle, and he designed an apparatus to which twenty-five wires were attached; and by touching keys which corresponded to the letters of the alphabet, needles attached to the other ends of the wires were set in motion by the action of an electric current. It was this incipient and very imperfect design that Professor Wheatstone brought to perfection by a series of inventions and discoveries extending over a number of years. His own account of the origin of his telegraph is candid and interesting. “When, in 1823,” he says, “I made my important discovery that sounds of all kinds might be transmitted perfectly and powerfully through solid wires and reproduced in distant places, I thought I had the most efficient and economical means of establishing telegraphic (or rather telephonic) communication between two remote points that could be thought of. My ideas respecting establishing a communication of this kind between London and Edinburgh you will find in the Journal of the Royal Institution for 1828. Experiments on a larger scale, however, showed me that the velocity of sound was not sufficient to overcome the resistance and enable it to be transmitted efficiently through long lengths of wire. I then turned my attention to the employment of electricity as the communicating agent; the experiments of Ronalds and others failed to produce any impression on the scientific world; this want of confidence resulted from the imperfect knowledge then possessed of the velocity and other properties of electricity; some philosophers made out a few miles per second; others considered it to be infinite; if the former were true, there would not be much room for hope; but if the velocity could be proved to be very great there would be encouragement to proceed. I undertook the inquiry, and with the result the whole scientific world is acquainted. At the same time I ascertained that magnetic needles might be deflected, water decomposed, induction sparks produced, &c., through greater lengths of wire than had yet been experimented upon. In the following year, at the request of the Royal Society, I repeated these experiments with several miles of insulated wire, and the results were witnessed by the most eminent philosophers of Europe and America. I ascertained experimentally (which had never been done before) many of the conditions necessary for the production of the various magnetic, mechanical, and chemical effects in very long circuits; and I devised a variety of instruments by which telegraphic communication should be realised on these principles.

“Some time before Mr. Cooke introduced himself to me I considered my experiments to be sufficiently matured to enable me to undertake some important practical results. I informed Mr. Fox, the engineer of the London and Birmingham Railway, of my expectations, and told him of my willingness to superintend the establishment of an electric telegraph on that railway. I had also made arrangements for trying an experiment across the Thames. Mr. Enderby kindly undertook to prepare the insulating rope containing the wires and to obtain permission from Mr. Walker to carry the other termination to his shot tower. After many experiments had been made with the rope, and the permission granted, I relinquished the experiment, because after my connection with Mr. Cooke it was necessary to divert the funds I had destined for this purpose to other uses. What I have stated above is sufficient to show that I had paid great attention to the subject of telegraphic communication by means of electricity, and had made important practical advances long before I had any acquaintance with or ever heard of Mr. Cooke.”

On reading this account two questions arise: first, whether the Wheatstone telegraph was the first of its kind; and, secondly, whether there is any corroborative evidence of the early labours of its inventor. These two questions at the time became interlinked in a singular way. In 1833 the celebrated scientists, Gauss and Weber, placed a line of wire from the Observatory of Göttingen University to a building a mile distant, and by sending magneto-electric currents through that wire they communicated intelligible signals; but as the needle they used weighed nearly a hundredweight they saw that their apparatus needed much improvement before it would be of practical utility. Being otherwise engaged themselves, they invited Professor Steinheil, of Munich, to construct an improved electric telegraph; and Steinheil, after much labour, succeeded in producing an apparatus capable of transmitting signals, but it was too refined for practical working with the means then available. His instrument for receiving and recording the signals consisted of two needles, one of which was to be moved by a positive and the other by a negative current, both currents being sent through one wire. Connected with each needle was a small reservoir of ink and a pen, which, on being depressed by the motion of the needle, marked a line upon a strip of paper that was drawn along by means of clockwork. At first he used a second wire for the return circuit, but in the course of his experiments he discovered that the earth was the best receiver of the return current, and accordingly dispensed with the second wire. Now, strange to say, the experiments connected with this telegraph of Steinheil’s became indirectly a circumstantial witness of Professor Wheatstone’s labours before ever he saw Mr. Cooke.

The number of the Magazine of Popular Science published on March 1st, 1837, contained “an account of some new experiments in electro-magnetism.” It was a description of the experiments of Gauss at Göttingen, communicated to the Munich Academy of Sciences by Prof. Steinheil, who, in concluding, stated that he himself “had fitted up a telegraph similar in principle to that which connected the Observatory and the Cabinet of Natural Philosophy at Göttingen. Signals made in the room appropriated to the magnetic observations were transmitted to another department at a considerable distance, whence the answers were returned to the first room. He had arranged this apparatus for the purpose of demonstrating the peculiarities and the practicability of Professor Gauss’s contrivance, hoping by these means to draw attention to it, and to induce persons to employ it for connecting stations far more distant than any to which it has yet been applied.” To that was added the following: “Note by Editor: During the month of June last year (1836), in a course of lectures delivered at King’s College, London, Professor Wheatstone repeated his experiments on the velocity of electricity, which were published in the Philosophical Transactions for 1834, but with an insulated circuit of copper wire, the length of which was now increased to nearly four miles; the thickness of the wire was 1/16th of an inch. When machine electricity was employed, an electrometer placed on any point of the circuit diverged, and wherever the continuity of the circuit was broken, very bright sparks were visible. With a voltaic, or with a magneto-electric machine, water was decomposed, the needle of a galvanometer deflected, &c., in the middle of the circuit. But, which has a more direct reference to the subject of our esteemed correspondent’s communication from Munich, Professor Wheatstone gave a sketch of the means by which he proposes to convert his apparatus into an electric telegraph, which, by the aid of a few finger-stops, will instantaneously and distinctly convey communications between the most distant points. These experiments are, we understand, still in progress, and the apparatus, as it is at present constructed, is capable of conveying thirty simple signals, which, combined in various manners, will be fully sufficient for the purposes of telegraphic communication.”

These words must have been in type, and most probably were printed before the day on which Mr. Cooke said he first saw Professor Wheatstone; and they were certainly printed before the date fixed by Professor Wheatstone as the time of Mr. Cooke’s introduction to him. Professor Wheatstone says:

“I believe it was on the first day of March, 1837, that Mr. Cooke introduced himself to me. He told me that he had applied to Dr. Faraday and Dr. Roget for some information relative to the subject on which he was engaged, and that they had referred him to me. He gave me no clue as to the purpose he had in hand. I replied that he was welcome to all the information I could give him, and that the experiments I had been making for some time relative to employing electric currents for the purpose of telegraphic communication would enable me to give him much of the information he required. At our next interview shortly after, he told me he was working at an electric telegraph, and that the questions he had previously put to me related to this subject. After that I showed him some of my apparatus, and explained my proposals. Mr. Cooke showed me some of his drawings and models. I at once told him it could not act as a telegraph, and to convince him of the truth of this assertion I invited him to King’s College to see the repetition of my experiments. He came, and after seeing a variety of voltaic magnets, which even with powerful batteries exhibited only slight adhesive attraction, he expressed his disappointment in these words which I well remember: ‘Here is two years’ labour wasted.’

“With regard to Mr. Cooke’s invention, so far from its being practically useful, he has never, during my whole acquaintance with him, shown it to me in action, even in a short circuit. Mr. Cooke’s intention was, as he told me in the early stage of our acquaintance, to take out a patent for his invention. Mine was, when I had finished my experiments, to publish the results, and then to allow any person to carry them into effect. When Mr. Cooke found that his instrument was inapplicable to the purpose proposed, and that my researches were more likely to be practically useful, he proposed a partnership, and that we should take out a joint patent. The proposal did not proceed from me, and the sole reason of my acquiescing in the arrangement was that Mr. Cooke appeared to me to possess the zeal, ability, and perseverance necessary to make the thing successful as a commercial enterprise. I felt confident of overcoming myself all the scientific and mechanical difficulties of the subject, but neither my occupations nor my inclination qualified me for the part Mr. Cooke promised to perform. He said he was not wanting a scientific reputation, his sole object being to make money by it.

“The magnetic needle telegraph, as it appears in its most perfect state in the lecture room of the college, is to all intents and purposes entirely and exclusively my own invention. The original suggestion of Ampère (that a telegraph should be constructed by utilising the tendency of the magnetic needle always to place itself at right angles to an adjoining wire through which an electric current passed) was all that I borrowed in it. The most important point was my application of the theory of Ohm to telegraphic circuits, which enabled me to ascertain the best proportions between the length, thickness, and circumference of the multiplying coils and the other resistances in the circuit, and to determine the number and size of the elements of a battery to produce the maximum effect. With this law and its applications none of the persons who had before occupied themselves with experiments relating to electric telegraphs, had been acquainted.”

It may here be explained that Ohm was another eminent electrician, whose immortal discovery was at first consigned to neglect. His work, expounding the principle now known as Ohm’s law, was published at Berlin in 1827; but was not translated into English till 1841. It is said that for the first ten years after the publication of his work, only one continental author admitted or confirmed his views, but between 1836 and 1841, scientific men began to appreciate the value of his researches. Wheatstone was one of them. In 1841 Ohm was presented with the Copley gold medal of the Royal Society, when the President said: “Ohm has shown that the usual vague distinctions of intensity and quantity have no foundation, and that all the explanations derived from these considerations were perfectly erroneous. He has demonstrated both theoretically and experimentally that the action of a circuit is equal to the sum of the electromotive force (E. M. F.) divided by the sum of the resistances, and that whatever the nature of the current, whether voltaic or thermo-electric, if this quotient be equal, the effect is the same.”

Mr. George Cruikshank afterwards published a statement confirming the claims of Professor Wheatstone. He said that having been a friend of Professor Wheatstone, he wished to state that “the discovery of the telegraph arose from the circumstance that when first appointed lecturer at King’s College, he had seven miles of wire in the lower part of the building which abuts upon the river Thames, for the purpose of measuring the speed of lightning or the electric current. Upon one occasion when explaining his experiments to me, he said: ‘I intend one day to lay some of this wire across the bed of the Thames and to carry it up to the Shot Tower on the other side, and so to make signals.’ This was, I believe, the first idea or suggestion of a submarine telegraph. We are also indebted to him for the electric bell, for long before the telegraph came before the public, in explaining the machine to me, he said that as it was possible that one party might be asleep at one end of the wire, he had so arranged the working that the first touch should ring the bell at the other end, even if thousands of miles apart. This, it will be admitted, is an important part of the discovery.”

Next to the mechanism by which electric signals are made intelligible, one of the most important inventions is that by which an electric current is enabled to renew its strength as it goes along a great length of wire. The apparatus used for this purpose is called a relay, and the first man to publish an account of it was Prof. Wheatstone. Its mechanism is delicate and sometimes complex, but its principle can be easily understood. Most people understand that when a railway train has run a great distance, the engine requires to take in water or coal, and for that purpose it sometimes moves on to a siding in connection with which there is a constant supply of water or coal. In like manner, on long telegraphic lines electric batteries are kept in readiness at certain distances; but if they were connected with the main line it is obvious that their contents would be uselessly dissipated. They are therefore kept in a kind of siding, and are only temporarily connected with the main line for the purpose of replenishing a passing current. In the case of a railway the service of a pointsman is often needed to connect and disconnect a siding; but in the case of the telegraph the connecting link between the replenishing battery and the main line is made self acting. This is effected by the use of that property of electricity which causes an electrified wire to attract to it an adjacent piece of wire or iron. In the relay a needle or lever is so adjusted that when a feeble current comes along the main line, it attracts the needle of the relay line, and by means of this connection a fresh current from the local battery flows on to the line, and does the work which the original current had become too feeble to accomplish. This invention was embodied in the first patent of Professor Wheatstone; and Professor Henry, of New York, has sworn to the fact that when he was in London, in 1837, Professor Wheatstone showed him in King’s College, early in April, his method of bringing into action a second galvanic current by means of the deflection of a needle. Professor Bache was also present.

The first patent was taken out in June, 1837, in the joint names of Cooke and Wheatstone. Their telegraph had five wires and five needles. The guiding principle of their signalling apparatus was that a current of electricity on passing along a wire deflected the magnet or needle. Professor Wheatstone candidly acknowledged that he was not the discoverer of that principle; but it was he who discovered the practical basis upon which the wires and magnets should be adjusted so as to produce the desired effects. He arranged in a row five needles like those in a mariner’s compass; and when a current of electricity was sent along one of the wires the needle attached to it could be deflected to the right or left at the will of the sender. In the original form of the receiving instrument the needle was worked or deflected upon the face of a dial, upon which the letters of the alphabet were so arranged that any letter could be indicated at will by the sender making two of the deflected needles converge towards the desired letter. Any person could manipulate this instrument, as there was no secrecy or code involved in its signals.

A glance at the illustration will show the simplicity of this apparatus. The objection to it was that it required five wires to transmit the signals and a sixth wire to bring back the electricity after it had done its work. But the only other electric telegraph then announced in England required twenty-six wires; and it is in comparison with previous efforts that the first Wheatstone instrument should be judged. It is a curious fact that just fifty years after the invention of this instrument with six wires, a new system of telegraphing was tried by which six messages could be sent almost simultaneously on one wire, either all in one direction, or part of them in one direction and the remainder in the opposite direction.

The first electric telegraph designed by Wheatstone was laid down on the North Western Railway between Euston Square and Camden Town Stations, a distance of a mile and a half. It was first worked on the evening of July 25th, 1837, which may be considered as the birthday of the electric telegraph in England. Let us see how and where it came to pass. Late in the evening, in a dingy little room near the booking office at Euston Square, by the light of a flaring dip candle, which only illuminated the surrounding darkness, sat the inventor with a beating pulse and a heart full of hope. In an equally small room at Camden Town Station, where the wires terminated, sat Mr. Cooke, his co-partner, and among others two witnesses well known to fame, Mr. Charles Fox and Mr. Stephenson. These gentlemen listened to the first word spelled by that trembling tongue of steel, which will only cease to speak with the extinction of man himself. Mr. Cooke, in his turn touched the keys and returned the answer. “Never,” said Professor Wheatstone, “did I feel such a tumultuous sensation before, as when all alone in the still room I heard the needles click, and as I spelled the words I felt all the magnitude of the invention now proved to be practicable beyond cavil or dispute.”

Nevertheless the public treated it with indifference; the directors of the railway soon gave it notice to quit, and one of them even denounced it as “a new-fangled thing.”

The next line of telegraph was made on the Great Western Railway. In July, 1839, a line of wires was laid from Paddington to West Drayton, a distance of thirteen miles. An arrangement had been made between the Railway Company and Messrs. Cooke and Wheatstone to the effect that within a certain number of months after the telegraph had been laid and efficiently worked between these two places, the Railway Company might call on the patentees to give them a license for the whole of the line, and the Railway Company had the power to construct a telegraph all the way from Bristol to London for a certain number of years; but the work not being done within the prescribed time, the agreement became void, and for some time the telegraph did not extend beyond Slough—a distance of seventeen miles. From the first the line to West Drayton worked satisfactorily. For the purpose of testing whether it could be relied on, it was used for nearly two months to communicate to Paddington the moment of the passing of the trains at West Drayton and Hanwell, and it was found to answer admirably. The cost of making that line was from £250 to £300 a mile, including the charge for station instruments. At first the wires placed in a tube were put underground, but it was soon found better to have them above ground, where they were less liable to injury from wet.

Early in 1840 Professor Wheatstone claimed as the result of experience that thirty signals could be conveniently made in a minute by this telegraph, and at the same time he stated that “having lately occupied myself in carrying into effect numerous improvements which had suggested themselves to me, I have, in conjunction with Mr. Cooke, who has turned his attention greatly to the same subject, obtained a new patent for a telegraph which I think will present very great advantages over the present one. It can be applied without entailing any additional expense by simply substituting new instruments for the old ones. This new instrument requires only a single pair of wires to effect all that the present one does with five; so that three independent telegraphs may be immediately placed on the line of the Great Western. It presents in the same place all the letters of the alphabet according to the order of succession, and the apparatus is so extremely simple that any person, without any previous acquaintance with it, can send a communication and read the answer.”

When Professor Wheatstone made the above statement, he also explained that Mr. Cooke had devised an apparatus whereby a bell worked by one wire could be rung at the other end of the wire by the sender, in order to draw the attention of the receiver to the message about to be sent. He added that Mr. Cooke had particularly directed his attention to an arrangement by means of which communications could be made from intermediate parts of the line where there were no fixed stations. For that purpose posts were placed at every quarter of a mile along the line from which the guard of a train might, if necessary, send a message to a station in either direction by means of a portable instrument which he was to carry with him.

It was in the same year, after these statements were made, that Mr. Cooke began his series of complaints against Professor Wheatstone, whom he accused of claiming the invention of the telegraph as his exclusive work, and of omitting all mention of his (Mr. Cooke’s) name in connection with it. Mr. Cooke now (1840) maintained that he himself had invented the first telegraph, and thereupon a war of words arose as to the respective parts played by the patentees in the joint undertaking.

The controversy thus raised between the two partners, instead of being allowed to produce an instant rupture, which might have injured the progress of the telegraph, was submitted to the decision of Sir M. Isambard Brunel, engineer of the Thames Tunnel, and Professor Daniell, of King’s College, the one a friend of Mr. Cooke and the other a friend of Professor Wheatstone, and on April 27th, 1841, these two gentlemen drew up the following statement: “In March, 1836, Mr. Cooke, while engaged at Heidelberg in scientific pursuits, witnessed, for the first time, one of those well-known experiments with electricity considered as a possible means of communicating intelligence which have been tried and exhibited from time to time during many years by various philosophers. Struck with the vast importance of an instantaneous mode of communication to the railways then extending themselves over Great Britain as well as to Government and general purposes, and impressed with the strong conviction that so great an object might be practically attained by means of electricity, Mr. Cooke immediately directed his attention to the adaptation of electricity to a practical system of telegraphing, and giving up the profession in which he was engaged, he from that hour devoted himself exclusively to the realisation of that object. He came to England in April, 1836, to perfect his plans and instruments. In February, 1837, while engaged in completing a set of instruments for the intended experimental application of his telegraph to the tunnel of the Liverpool and Manchester Railway, he became acquainted, through the introduction of Dr. Roget, with Professor Wheatstone, who had for several years given much attention to the subject of transmitting intelligence by electricity, and had made several discoveries of the highest importance connected with this subject. Among these were his well-known determination of the velocity of electricity when passing through a metal wire; his experiments in which the deflection of magnetic needles, the decomposition of water, and other voltaic and magneto-electric effects were produced through greater lengths of wire than had ever before been experimented upon; and his original method of converting a few wires into a considerable number of circuits, so that they might transmit the greatest number of signals that can be transmitted by a given number of wires by the deflection of magnetic needles.

“In May, 1837, Messrs. Cooke and Wheatstone took out a joint English patent on a footing of equality for their existing inventions. The terms of their partnership, which were more exactly defined and confirmed in November, 1837, by a partnership deed, vested in Mr. Cooke as the originator of the undertaking the exclusive management of the invention in Great Britain, Ireland, and the Colonies, with the exclusive engineering department, as between themselves, and all the benefits arising from the laying down of the lines and the manufacture of the instruments. As partners standing on a perfect equality, Messrs. Cooke and Wheatstone were to divide equally all proceeds arising from the granting of licenses or from the sale of patent rights, a percentage being first payable to Mr. Cooke as manager. Professor Wheatstone retained an equal voice with Mr. Cooke in selecting and modifying the forms of the telegraphic instruments, and both parties pledged themselves to impart to each other for their equal and mutual benefit all improvements of whatever kind which they might become possessed of connected with the giving of signals or the sending of alarms by means of electricity. Since the formation of the partnership the undertaking has rapidly progressed under the constant and equally successful exertions of the parties in their distinct departments, till it has attained the character of a simple and practical system worked out scientifically on the sure basis of actual experience.

“While Mr. Cooke is entitled to stand alone as the gentleman to whom this country is indebted for having practically introduced and carried out the electric telegraph as a useful undertaking, promising to be a work of national importance; and Professor Wheatstone is acknowledged as the scientific man whose profound and successful researches had already prepared the public to receive it as a project capable of practical application; it is to the united labours of two gentlemen so well qualified for mutual assistance that we must attribute the rapid progress which this important invention has made during the five years that they have been associated.”

For a time the rivalry or jealousy seemed at rest. Both Mr. Cooke and Professor Wheatstone concurred in the above statement, and Mr. Cooke gave prominence to the portions of it most favourable to him, claiming that such passages formed the award of an arbitration that resulted in his favour. But Professor Daniell in 1843 explained that this document was not an “award” of the arbitrators, for the arbitration was not proceeded with. The arbitrators, considering the pecuniary interests at stake and the relative position of the parties, were of opinion, he said, that without entering into the evidence of the originality of the invention on either side, a statement of facts might be drawn up, of the principal of which there appeared to be no essential discrepancy in the statement of either party, and that they might thus amicably settle the unfortunate misunderstanding that had occurred. He added that with a view to promote such an amicable settlement the arbitrators insisted, as a preliminary step, upon the withdrawal and destruction of 1000 copies of an ex parte statement of evidence proposed to be brought forward, and of a most intemperate address prepared by Mr. Cooke’s solicitor.

The lull produced by that document was only temporary. When anything was published making favourable mention of Professor Wheatstone’s originality as the inventor of the telegraph, Mr. Cooke or his partisans openly accused the Professor of tampering with the press, and Mr. Cooke himself was not above publishing protestations for the purpose of showing his “own surprising forbearance,” as well as the “egotism,” “humiliation,” and “perseveringly repeated misrepresentations” of Professor Wheatstone!

In later years Mr. Cooke or his friends paraded before the public an article in his favour that appeared in a quarterly review since deceased. That article was represented as having been written by Sir David Brewster, and as giving a correct account of the origin of the telegraph. It stated that Mr. Cooke had previously held a commission in the Indian Army, “and having returned from India on leave of absence and on account of ill health, he afterwards resigned his commission and went to Heidelberg to study anatomy. In the month of March, 1836, Professor Möncke of Heidelberg exhibited an electro-telegraphic experiment in which electric currents, passing along a conducting wire, conveyed signals to a distant station by the deflection of the magnetic needle inclosed in Schweigger’s galvanometer or multiplier. The currents were produced by a voltaic battery placed at each end of the wire, and the apparatus was worked by moving the ends of the wires backward and forward between the battery and the galvanometer. Mr. Cooke was so struck with this experiment that he immediately resolved to apply it to purposes of higher utility than the illustration of a lecture, and he abandoned his anatomical pursuits and applied his whole energies to the invention of an electric telegraph. Within three weeks, in April, 1836, he made his first electric telegraph, partly at Heidelberg, and partly at Frankfort. It was of the galvanometer form consisting of six wires, forming three metallic circuits, and influencing three needles. By the combination of these, he obtained an alphabet of twenty-six signals. Mr. Cooke soon afterwards made another electric telegraph of a different construction. He had invented the detector, for discovering the locality of injuries done to the wires, the reciprocal communicator, and the alarm. All this was done in the months of March and April, 1836; and in June and July of the same year he recorded the details of his system in a manuscript pamphlet from which it was obvious that in July, 1836, he had wrought out his practical system from the minutest official details up to the records and extended ramifications of an important political and commercial engine.” The article goes on to say that when his telegraphic apparatus was completed, he showed it in November, 1836, to Mr. Faraday, and afterwards submitted it and his pamphlet in January, 1837, to the Liverpool and Manchester Railway Company, with whom he made a conditional arrangement, with the view of using it on the long tunnel at Liverpool. In February, 1837, when he was about to apply for a patent he consulted Mr. Faraday and Dr. Roget on the construction of the electro-magnet employed in a part of his apparatus, and the last of these gentlemen advised him to consult Professor Wheatstone, to whom he went, according to Mr. Cooke’s account, on the 27th of February, 1837.

Now the article containing these statements was doubtless attributed to Sir David Brewster in the hope that his name would be accepted as a guarantee of its accuracy. Fortunately for all concerned, however, Sir David Brewster had previously placed on record his opinion on this question of the telegraph in a manner that put it beyond doubt. Asked by a Committee of the House of Lords in 1851 whether Professor Wheatstone was the undoubted inventor of the electric telegraph, Sir David Brewster replied: “Undoubtedly he is.” Further asked whether there was not a Swede who had paid great attention to the subject, Sir David said Oersted was the discoverer of electromagnetism, but had that not been discovered at all, ordinary magnetism was quite capable of being the moving power in the electric telegraph. He added that if electromagnetism had been the only means of working a telegraph, then the merit, not of the telegraph, but of what was necessary to the existence of the telegraph, would have belonged to Professor Oersted. When, on the other hand, the same Committee pressed Sir I. K. Brunel to say whom he considered the inventor of the telegraph, he replied: “Messrs Cooke and Wheatstone derive a large sum of money from the electric telegraph; but I believe you will find fifty people who will say that they invented it also: I suppose it would be difficult to trace the original inventor of anything.”

It has never been denied, though often overlooked, that Mr. Cooke obtained his first idea of a telegraph from Professor Möncke of Heidelberg—a circumstance which detracts from its originality. But the matter did not rest there.

When Mr. (then Sir) W. F. Cooke died in 1879, Mr. Latimer Clark published the portion of his private correspondence which related to his first connection with Professor Wheatstone, and although Mr. Latimer Clark endeavoured to put everything in the light most favourable to Mr. Cooke, the letters of the latter in essential points confirm the case of Professor Wheatstone. For example, after writing numerous letters to his mother explaining that he was busy trying to make a telegraph, Mr. Cooke wrote on February 27th, 1837: “Dissatisfied with the results obtained, I this morning obtained Dr. Roget’s opinion, which was favourable but uncertain; next Dr. Faraday’s, who, though speaking positively as to the general results formerly, hesitated to give an opinion as to the galvanic fluid action on a voltaic magnet at a great distance when the question was put to him in that shape. I next tried Clark, a practical mechanician, who spoke positively in favour of my views, yet I felt less satisfied than ever, and called upon a Mr. Wheatstone, Professor of Chemistry at the London University, and repeated my inquiries. Imagine my satisfaction at hearing from him that he had four miles of wire in readiness, and imagine my dismay on hearing afterwards that he had been employed for months in the construction of a telegraph, and had actually invented two or three with the view of bringing them into practical use. We had a long conference, and I am to see his arrangement of wire to-morrow morning, &c.... The scientific men know little or nothing absolute on the subject. Wheatstone is the only man near the mark.” Mr. Latimer Clark accounts for the notice of Professor Wheatstone’s experiments in the Magazine of Popular Science for March, 1837, by saying that it was “evidently inserted after the remainder of the articles had been completed, and set in type,” and that Wheatstone supplied the information after Mr. Cooke’s visit to him—a gratuitous assertion which is not supported by any positive evidence. Then, again, Mr. Latimer Clark, an eminent authority upon the laws of electricity, says, concerning Mr. Cooke’s proposed telegraph, that “upon the whole the instrument, the result of such long cogitation and experiment, is disappointing, and one is not surprised at Wheatstone, with his exquisite mechanical appreciation, criticising it as severely as he did.” Moreover, he admits that the first telegraph instrument used between Camden Town and Euston was Wheatstone’s.

Not less emphatic or explicit was the statement of the case given by Professor Wheatstone himself, and moreover it contained some passages of biographical interest. Addressing Mr. Cooke, he said: “You state that you alone had succeeded in reducing to practical usefulness the electric telegraph at the time you sought my assistance. This I wholly deny. Your instrument had never been practically applied, and was incapable of being so. Mine were all founded on principles which I had previously proved by decisive experiments would produce the required effects at great distances. Your statement that I employed myself at your request in perfecting your invention in detail is equally erroneous. My time, so far as it was devoted to telegraphic researches, was exclusively occupied in perfecting my own instrument, which had nothing in common with yours, and in which I was not only known to be engaged by all my scientific friends, but which was even announced in public print before I knew of your existence. I confined myself to carrying out one of my own inventions for two reasons: First, because my experiments led me to believe that the motions of a needle could be produced at distances at which no effects of electro-magnetic attraction could be obtained; and, secondly, I did not wish to interfere with you. With regard to the subsequent development of my first telegraph, the essential principles of which are the formation of numerous circuits from a few wires and the indication of characters by the convergence of needles, I am indebted to no person whatever; it is in all its parts entirely and exclusively my own. The modifications you introduced without consulting me in the instruments for the Great Western Railway altered the simplicity and elegance of the arrangement without the slightest advantage, and I certainly should not recognise them in any published description.”

“The circumstances under which your name was allowed to take the lead in the titles of the British patents have escaped your memory. I will endeavour to recall them to you. When you first proposed partnership, you know how strongly I opposed it, and on what grounds. I said I was perfectly confident of being able to carry out my views to the end I anticipated, that I fully intended doing so, and publishing the results, then allowing any person to carry them into practical effect. I told you that, while I admired the ingenuity of your contrivance I deemed it inapplicable to the purpose proposed, and I urged that in that case the association of my name with that of others would diminish the credit I should obtain by separately publishing the result of my researches. You replied that you were not seeking scientific reputation, and therefore no difference could arise between us on that account, and that your sole object was to carry the project into profitable execution. A patent was arranged to be taken out in our joint names which should include our two separate instruments. When we met to settle the preliminaries for the English patent I was much surprised to find your name inserted first, considering that, as we put ourselves on an equality by each contributing an invention, to put my well-known name after yours, then totally unknown, might be construed into an admission of the superiority of your share. You urged that your pecuniary obligations were the greater, and that as I intended to leave negotiations with you, your authority might be less respected if your name appeared second, and that your invention was the more valuable—an assumption I did not admit, and the event proved I was right. But we agreed that in subsequent patents the order should alternate. Some time after we met to settle the Scotch patent draft, for which you had prepared the declaration. I was again surprised to find the same order of precedence repeated, and I objected to it as contrary to our previous understanding. You said it had been done without your knowledge, but objected to the alteration on the ground of delay. After discussion we made a new arrangement, that on my allowing your name to stand on the British patents, mine should take the lead in all foreign ones. It was resolved afterwards that an American patent should be obtained, and when I attended to sign the preliminary papers, I found that again, without any notice to me, my name was made to follow yours. I refused to sign the papers, and you then consented to keep your word. The only reason you alleged was that your authority as manager would be diminished if you appeared as second partner.

“When I had attained some complete results, I invited you to the College to see them, and before describing or showing the new experiments and instruments, I proposed conditions: That having, at my own expense, undertaken a series of investigations which led to important consequences greatly increasing the pecuniary value of the patents, and having invented new instruments which, besides being applicable to all the purposes for which the existing arrangements could be applied, might also be profitably applied to other purposes to which the previous instruments were not at all adapted, I required as a compensation that I should retain the exclusive right of manufacturing them and all instruments I should construct involving the same principles, and also the privilege of employing them exclusively for domestic and official purposes. To these conditions you assented, and afterwards I showed you the completed instruments, and read to you a list of the further experiments. You confirmed your assent. On this occasion you breathed not a word respecting the claim since put forward to be considered the joint inventor of my new instruments.

“You ask me to acknowledge that ‘I, having certain improvements on our joint invention in progress depending fundamentally upon principles first discovered and applied by you, had asked as a favour,’ &c. It is unjust to urge such an acknowledgment upon me, and I state plainly that nothing shall compel me to make it. My instruments are original combinations involving a great number of points entirely new. With equal justice Mr. Ronalds might call upon me to declare that he is the joint inventor, because, like him, I use a revolving dial with letters—or Professor Steinheil complain of my suppressing his name because, in one of my most recent important modifications I employ, as he has done, the magneto-electric machine—as you to put forth that claim, because in some of my new instruments I have employed magneto-electric attraction, which you had done before me in your instrument; or with the same reason might Mr. Morse call upon me to proclaim him to be joint inventor because he, independently of you, has employed an electro-magnet to move machinery intended for a telegraph. One of your complaints is, that in the notices of my experiments in Belgium the employment of two wires for an electric telegraph was not specifically mentioned as a discovery of yours. Such a claim on your part has no foundation, for, without going further back, Ronalds’ two telegraphs—two telegraphs on different principles, which I myself proposed before I knew you,—and Steinheil’s telegraph, with which I was acquainted before yours, had two wires. You forget that it is my electric telegraph, and not yours, that is in daily use. And, lastly, you forget that, had it not been for my exclusive attention to it since I first conceived the idea, a practical telegraph might still have remained an unaccomplished purpose.

“Do not, however, misunderstand me. Far be it from me to underrate your exertions; they have been very great, and absolutely indispensable to the success of our joint undertaking. Without your zeal and perseverance and practical skill, what has been done would not have been so readily effected; but on the other hand, I may say, that had you entered the field without me, your zeal, perseverance, and money would have been thrown away.”

His subsequent as well as his previous inventions afford the strongest evidence of his originality. His inventions were not more distinguished for ingenuity than for permanent usefulness, and they had this unusual characteristic, that nearly every one of them became the parent of a considerable offspring. These form his most enduring monument, and a simple record of them forms his best vindication.

In 1840 he produced three inventions at one birth—his dial telegraph, his printing telegraph, and his electric clock. Each of these instruments was worked by utilising one of the great discoveries previously made in electro-magnetism. It was known that when an electric current is sent through a wire coiled round a piece of soft iron, the iron becomes a magnet. If the current is stopped for a moment, the iron instantly ceases to act as a magnet. When the piece of iron is magnetic, it will attract another piece of iron, and as the attraction ceases as soon as the current ceases, the iron can then by means of a spring be made to resume its original position. Thus by frequently interrupting an electric current, a piece of iron held in its place by a small spring can be made to move to and fro as often as it is attracted. Professor Wheatstone invented a method of regulating the application of the current to such a magnet, and of converting the to-and-fro motion of the iron into symbols. The piece of mechanism that regulated the current was a wheel called a commutator or communicator; around its circumference were twenty-four teeth; and each tooth was made to act as a conductor of electricity in this way: Under the teeth of the communicator there was a metallic circle which was connected with the telegraph wire; and in this metallic circle twenty-four pieces of wood were inserted at equal distances apart; so that the teeth of the communicator, which was connected by wire with the battery, at one moment touched the conducting metal of the circle underneath it, and thus imparted a current to the telegraph wire, while at the next turn a pace round they rested on the non-conducting wood, by which the current was prevented from passing from the communicator wheel to the telegraph wire. In a complete revolution of such a wheel the current would be twenty-four times established and as often interrupted; and each of these twenty-four alternations was made to indicate a letter of the alphabet at the other end of the wire by means of a piece of mechanism like a clock. When the current passed along the wire, it electrified a magnet, which then drew towards it an armature (a piece of iron). The movement of this armature (forward by electricity and backward again by a spring) acted like a pendulum in moving a wheel, which in turn moved a hand on a dial containing the letters of the alphabet. Just as at each movement of the pendulum of a clock, a wheel moves one tooth forward; so at each movement of the armature by an electric current, a twenty-four toothed wheel was moved one tooth forward, and at each such movement the hand on the dial moved from one letter of the alphabet to the next one. If, for instance, the indicator hand stood at A and it was desired to transmit E, this would be done by moving the communicator wheel four teeth onward; in doing that four successive currents would be transmitted to the indicator, the hand of which would consequently move over B, C, D, and then reach E, where a pause would indicate that this was the letter intended to be read. This was called Wheatstone’s electro-magnetic telegraph, because it was worked by an electric current from a battery electrifying a magnet.

In 1841 he invented a machine in which magnets produced electricity sufficient to work the telegraph. Hence it was called a magneto-electric machine, and the telegraph worked by it was called a magneto-electric telegraph. In 1840 he explained that magneto-electricity was of momentary duration as contrasted with the continuous action of electro-magnetism. The magneto-electric machine then in use consisted of a coil or coils of insulated wire being made to revolve in the vicinity of a magnet, or the magnet revolving in the vicinity of the insulated coils of wire, and this apparatus only produced a series of shocks, or instantaneous as compared with continuous currents. His new invention combined several of these machines into one by so uniting their coils as to form one continuous circuit, thereby producing the same effect as a perfectly continuous current. He said this magneto-electric machine could be used for many purposes for which a voltaic battery had been employed. The patent for it was taken out in his own name.

Meanwhile another competitor had begun to challenge his originality. On November 26, 1840, Professor Wheatstone read a paper before the Royal Society describing his electro-magnetic telegraph clock as his own invention. He also showed the clock in action in the library. In January following he received notice from a Mr. Barwise, of St. Martin’s Lane, that he claimed to be the inventor of the clock, and shortly afterward it was stated in placards that Messrs. Barwise and Bain were the joint inventors. At first Professor Wheatstone took little notice of the attacks thus made upon his originality, but in June, 1842, he was directly charged by Mr. Bain in the public press with appropriating his inventions. In reply to that accusation, Professor Wheatstone stated that Alexander Bain was a working mechanic who had been employed by him between the months of August and December, 1840; and to the allegation that Bain communicated the invention of the clock to him in August, 1840, he answered that there was no essential difference between his telegraph clock and one of the forms of his electro-magnetic telegraph, which he had patented in January, 1840; that the former was one of the numerous and obvious applications which he had made of the principle of the telegraph, and that it only required the idea of telegraphing time to present itself and any workman of ordinary skill could put it in practice—in telegraphing messages the wheel for making and breaking the circuit was turned round by the finger of the operator, while in telegraphing time it was carried round by the arbor of a clock. He also stated that, long before the date specified, he mentioned to many of his friends how the principle of his telegraph could be applied “to enable the time of a single clock to be shown simultaneously in all the rooms of a house, or in all the houses of a town connected together by wires.” The accuracy of these statements was verified by Dr. W. A. Miller, of King’s College, and by Mr. John Martin, the eminent artist. The latter stated that Professor Wheatstone explained to him in May, 1840, his proposed application of his electric telegraph for the purpose of showing the time of a distant clock simultaneously in as many places as might be required. Mr. Martin, on hearing the explanation, said to him, “You propose to lay on time through the streets of London as we now lay on water.” Mr. F. O. Ward, a former student of King’s College, stated that Professor Wheatstone explained the matter to him on June 20, 1840. While watching the motions of the dial telegraph as he turned the wheel that made and broke the circuit, Mr. Ward remarked that if it were turned round at a uniform rate, the signals of the telegraph would indicate time, to which Professor Wheatstone replied: “Of course they would, and I have arranged a modification of the telegraphic apparatus by which one clock may be made to show time in a great many places simultaneously;” and the Professor showed him drawings of an apparatus for that purpose, in which the making and breaking of the circuit by the alternate motion of the pendulum of a clock, would produce isochronous signals on any number of dials, provided they were connected by wire. The electric clock in question has been repeatedly tried, but has not answered expectations.

Mr. Alexander Bain also accused Professor Wheatstone of appropriating his printing telegraph. He said he communicated the invention of the electric clock, together with that of the electro-magnetic printing telegraph, to Professor Wheatstone in August, 1840, before ever Professor Wheatstone did anything in the matter. To that the Professor replied that the printing apparatus was merely an addition to the electro-magnetic telegraph, of which he was undoubtedly the inventor. As to the way in which this telegraph printed the letters, he explained that for the paper disc (or dial) of the telegraph, on the circumference of which the letters were printed, he substituted a thin disc of brass, cut from the circumference to the centre so as to form twenty-four radiating arms on the extremities of which types were fixed. This type-wheel could be brought to any desired position by turning the commutator wheel. The additional parts consisted of a mechanism which, when moved by an electro-magnet caused a hammer to strike the desired type—brought opposite to it—against a cylinder, round which were rolled several sheets of thin white paper along with the alternate blackened paper used in manifold writing. By this means he obtained at once several distinct printed copies of the message transmitted. He maintained that the plan was begun and carried out solely by himself; and Mr. Edward Cowper stated, as corroborative evidence, that on June 10, 1840, he sent a note to Professor Wheatstone (who had previously told him of the contrivance by which his telegraph could be made to print), giving him information, which he had asked for, respecting the mode of preparing manifold writing paper, and the best form of type for printing on it.

It was also at the beginning of 1840 that he invented the “chronoscope,” an instrument for measuring the duration of small intervals of time. It was used for measuring the velocity of projectiles, and consisted of a clock movement set free at the moment a ball was discharged from a gun, and stopped when the ball reached the target. For this purpose a wire in an electric circuit at the gun’s mouth was broken at the instant the ball passed out of the gun; and the circuit was completed when the ball reached the target, the circuit acting on the clock movement by means of an electro-magnet. It was publicly stated in 1841 by independent witnesses that the chronoscope was capable of indicating the one 7300th part of a second; and the inventor himself stated in 1845 that with it the law of accelerated velocities had been obtained with mathematical rigour, that with it he could measure the fall of a ball from the height of an inch, and that by different arrangements which he had adopted to render the instrument applicable to different series of experiments, he intended to employ it for measuring the velocity of sound through air, water, and masses of rock, with an approximation that had never been obtained before.

In 1843 he brought before the Royal Society several methods of measuring the force of an electric current, and the paper he then read, and the methods he described, were for many years unrivalled both for simplicity and ingenuity. Speaking of electricity as an energetic source of light, of heat, of chemical action, and of mechanical power—prescient words in those days—he said it was only necessary to know the conditions under which its various effects may be most economically and energetically manifested to enable us to determine whether the high expectations formed in many quarters of some of its daily increasing practical applications are founded on reasonable hope or on fallacious conjecture. He considered that they had ample theory, but not enough of experiment to supply, except in a few cases, the numerical value of the constants which enter into various voltaic circuits; and without that knowledge accurate conclusions could not be arrived at. He explained that electro-motive force (E.M.F.) meant the cause which in a closed circuit originated an electric current; that by resistance was signified the obstacle opposed to the passage of the electric current by the bodies through which it passed; and that resistance was the inverse of what is usually called their conducting power. The principle of his methods was the use of variable instead of constant resistances, bringing thereby the currents compared to equality, and inferring from the amount of the resistances measured out between two deviations of the needle the electro-motive force and the resistances of a circuit, according to the particular conditions of the experiment. If a needle be connected with two coils of wire, and if a current be sent through one coil, the needle will be deflected to one side. If at the same time a current of the same strength be sent through the other coil, the currents will neutralize each other and the needle will remain at rest. This is what is called a differential galvanometer, and when two currents of different strength are sent through it simultaneously the needle is only affected by their difference. One form in which Professor Wheatstone used this principle has ever since been known as “the Wheatstone bridge.” It is a method by which pieces of wire of known resistance are interposed in a circuit until the current in the wire to be tested counter-balances that of the wire used as a standard of resistance; when that happens the needle indicator stands still, the wire to be tested being now of the same resistance as that of the known standard. Professor Wheatstone perceived that it was of the highest importance to have a correct standard of resistance, and one that could be easily reproduced for the purpose of comparison. He therefore adopted as a unit of resistance a copper wire one foot in length, 100 grains in weight, and ·071 of an inch in diameter. He was the first man who made a unit of resistance, and who introduced into electrical science the name of a unit and multiples of a unit; and when, nearly a quarter of a century afterward, the British Association appointed a committee on electrical standards, their reports describing about a dozen standards, paid a tribute to the originality of Professor Wheatstone as the introducer of the first unit. He was not, however, the first to use the method of measuring electrical currents or the resistance of wires, since known as the Wheatstone Bridge. In a note appended to his paper read before the Royal Society in 1843 he stated that Mr. Christie had described the same principle in the Philosophical Transactions for 1833, and added that “to Mr. Christie must therefore be attributed the first idea of this useful and accurate method of measuring resistances.” Mr. Christie, who was connected with the Royal Military Academy at Woolwich, said in his paper that the arrangement he proposed possessed many advantages; it afforded a very accurate measure of the difference of intensities of two electric currents, whether they were from the same source and were merely modified by circumstances, or had different sources; and it afforded likewise a very accurate measure of the conducting powers of different substances. Mr. Christie did not, however, succeed in drawing attention to this method, and it lay unheeded till Professor Wheatstone revived it and expounded it with matchless clearness. He at the same time devised an instrument called the Rheostat, in which a highly resisting wire was so wound round the surface of a cylinder that any length of it could be connected with a circuit by merely turning round the handle of the cylinder till the needle or galvanometer connected with it showed that the resistance of the wire on the cylinder was equal to that of the wire to be tested. As the resistance of the wire on the cylinder was accurately known beforehand, the length of it required to counterbalance the resistance of the wire in course of being tested became the measure of the latter. The wire on the cylinder may be compared to a winding measuring line; only being of high resisting power, a short length of it suffices to measure a long wire of low resistance.

Professor Wheatstone told the Royal Society in 1843 that he had employed the Rheostat and differential resistance measurer (the Wheatstone Bridge) for several years previously for the purpose of investigating the nature of electrical currents—a statement which had received a singularly generous corroboration; for in 1840 Professor Jacobi told the British Association meeting in Glasgow that Professor Wheatstone had shown him in London an instrument for regulating a galvanic current, similar in principle to one that he had laid before the St. Petersburg Academy of Sciences at the beginning of that year. Professor Jacobi, in stating that it was quite impossible that Professor Wheatstone could have had any knowledge of his similar instrument, said he must add that while he had only used his instrument for regulating the force of currents, Professor Wheatstone had founded upon it a new method of measuring those currents and of determining the different elements of them.

The Royal Society, which in 1840 had presented him with a royal medal “for the ingenious method by which he had solved the difficult question of binocular vision,” presented him with another medal in 1843, when the President, the Marquis of Northampton, said: “I now present you with this medal, one of those intrusted to the President and Council of the Royal Society by Her Most Gracious Majesty, for your paper entitled, ‘An account of several new Instruments and Processes for determining the Constants of the Voltaic Circuit.’ This is not the first time that I have had the pleasing task of acknowledging on the part of the Royal Society the great ingenuity as well as knowledge that you bring to the increase of science. You not only add to our store of knowledge, but you give to others the means of doing so too. You not only set the example of scientific pursuit, but you also facilitate it in those who may become at once your followers and your rivals. In the particular case before us you have introduced accuracy where even rough numerical data were almost wholly wanting. The improvement of such facilities in any branch of science can hardly be overstated.”

In 1845 a patent was taken out for a new form of needle telegraph, respecting the origin of which Mr. Latimer Clark relates the following incident as told to him by Mr. Greener some fifteen years after it occurred. A very high tide which occurred in 1841 caused an inundation of the Blackwall Railway, and injured the piping in which were inclosed the seven or eight wires then in use—they were then using a wire to each station; so that only one wire or two could be worked. Mr. Cooke, who was the practical engineer of the telegraph, was much concerned lest some accident might happen through the failure of the telegraph, whereby they would, he feared, be unable to communicate with the intermediate stations from the Blackwall end of the line. In view of this contingency Mr. Greener and another clerk arranged a code of signals which could be worked on one wire by simply deflecting the needle alternately, once, twice, or thrice, to the right or left; and in this way they managed to carry on communications respecting their dinners and other private matters. “Mr. Cooke, on being informed that it was still possible to telegraph, gladly availed himself of the new means of communication by one wire, and from that moment our well-known single and double-needle instrument was practically invented. If these statements be accurate the first idea of the double-needle telegraph did not originate either with Wheatstone or Cooke, but was suggested by Mr. Greener and his partner, who was at this time engaged with him on the Blackwall telegraph.”

In the popular accounts of great discoveries or inventions it is generally the falling of an apple that is said to suggest to a Newton the law of gravitation, or it is the boiling of a tea-kettle that suggests to a Watt the mechanism of the steam-engine. This has become the orthodox way of accounting for the triumphs of mind over matter in order to make them acceptable to intellectual mediocrity. Indeed, the Abbé Raynal says that the only difference between a genius and one of common capacity is that the former anticipates and explores what the latter accidentally hits upon. But, he adds, “even the man of genius himself more frequently employs the advantages that chance presents to him; it is the lapidary that gives value to the diamond which the peasant has dug up without knowing its worth.” Now it is a curious fact that while the needle telegraph was one of the few telegraphic inventions of Professor Wheatstone that was undisputed during his lifetime, the preceding account of its origin was never publicly mentioned till after his death.

Facts, however, are against its accuracy. The high tide referred to in the story occurred on November 18th, 1841, after the five-needle telegraph had been in operation on the Great Western Railway more than two years; and a few weeks’ experience of its working enabled a clerk of ordinary intelligence to tell the letters transmitted by the movement of the needles, even if the printed letters on the dial to which the needles pointed were covered over or obliterated. A minute’s examination of the five-needle instrument shows that a different combination of movements is required to represent each letter, and if these combinations be learned by a few weeks’ practice, or be written down on paper, they constitute a complete alphabet of signs. And that alphabet of signs which the five-needle instrument first taught could obviously be produced by a single needle. Thus on the five-needle instrument A is represented by the movement of the first needle to the right, and the fourth from it to the left; but it would also be represented by the movement of one needle first to the right and then four times to the left. In like manner B is represented on the five-needle instrument by the first needle moving to the right and the third from it to the left. By means of a single needle it could be represented by one movement to the right and three to the left; and so on with the other letters. Experience has suggested that the alphabet could be represented by fewer movements than those practically exhibited by the five-needle instrument; but it is obvious that a few weeks’ working of the five-needle instrument—and not a flood in the Thames—was sufficient to show that the movements of needles, without a dial or a printed alphabet, could be made to convey intelligence. This is no mere speculation. More than this was in actual operation on the Blackwall Railway; for in a contemporaneous account it is stated that the wires run all along the line inclosed in a metal tube, and the arrangement is such that whenever a particular index deviates to the right or left at the Minories Station, an index deviates to the right or left at all the other stations at the same instant. “If then,” says the contemporary writer, “a preconcerted alphabet, or key, or dictionary, or table of signals be agreed on, the relative positions of two or more index-hands will serve to convey a message. By the side of the telegraphic case a large chart is hung up, containing about a hundred sentences, instructions or questions, each of which is symbolled by a particular position of two or three index hands. Thus one position, capable of being effected by two movements of the handles, implies, ‘Will the next train wait for the next steam-boat?’ Another implies, ‘Will the steam-boat wait for the next train?’ And others: ‘How many passengers?’ ‘How many carriages?’ and various inquiries and directions relating to the engines, the ropes, the telegraphs, and the steam-boats which start from and arrive at Blackwall.” The writer added that by employing the combined simultaneous motion of three or four needles, the five-wire telegraph would afford nearly 200 signals, besides those appropriated to the alphabetic characters.

It thus appears that the idea of making the deviations of a needle represent messages or letters was not only obvious but in daily use. Yet the erroneous traditions that already envelop the infancy of this telegraph do not end here. The contemporaneous account just quoted concludes with the remark that a telegraph like that used on the Blackwall Railway and the Great Western Railway, if consisting merely of three needles and giving only twelve signs, has a power of combination fully equal to the semaphore then in use; and in recent years it has been represented by persons of authority in the telegraph world that the double-needle instrument formed the transition stage from five needles to one. Hence the single-needle instrument has generally been regarded as a gradual improvement of the parent instrument of five needles. But the fact is that both the single and double-needle instrument were minutely described in one and the same patent taken out in 1845. In that description, which would fill a chapter of this book, Professor Wheatstone was more careful to explain the advantages of the single than of the double-needle instrument. He expressly disclaimed any intention to lay down a particular signification to the signals by which the alphabet could be represented; he merely gave illustrations to show how easily a sufficient variety of signals could be obtained. At the same time he gave an alphabet of signs suitable for a single-needle instrument, and although experience has suggested a more convenient combination of signals, it is on record that within a year or two after the patent for the single and double-needle telegraphs was taken out, the single-needle instrument was tried on some of the railway lines, and the alphabet of signals used was that which the five needle instrument suggested, with slight modifications. The single needle, however, was considered deficient in rapidity; and consequently to obtain greater speed the double-needle instrument was preferred. One of the first lines to adopt it was the South Western; it soon came to be regarded as the most rapid means of telegraphing; and hence it came into general use. It maintained its supremacy in England till more expeditious instruments were invented, and then it was gradually superseded by the single-needle instrument, which was found to be more accurate and economical. Now the single-needle instrument may be seen at most railway stations and rural post offices in the United Kingdom. In this instrument the needle when moved by a current to the right hand or the left, strikes against a projecting pin placed on each side to arrest its motion; the sender by moving a handle can deflect the needle at will either to the right or the left; one deflection to the left and one to the right represents A; one to the right and three to the left B; one to the right, one to the left, another one to the right and another to the left C; one to the right and two to the left D; and so on. None of the twenty-four letters of the alphabet has more than four deflections. While E has one to the left, I has two, S three, and H four. T has one to the right, M two, O three, and Ch. four.

It was calculated that about 15,000 of these instruments were in use in Great Britain in 1885.

Meanwhile another improvement of a permanent nature had taken place. The use of the earth instead of a special wire as the return circuit was first adopted in England on the Blackwall Railway telegraph in 1841, and on the Manchester and Leeds line in 1843. The history of this improvement is curious. In 1838 Professor Steinheil used the earth to complete the circuit of an electric telegraph which he established at Munich, and he has generally been regarded as the first electrician who purposely did so. But William Watson discovered the same thing in 1747. He erected a wire fully two miles long over Shooter’s Hill, supporting it upon rods of wood. When electricity was communicated to the wire at one end, the shock at the other end appeared to be instantaneous, and the electricity was then communicated to the earth by means of a rod of iron. It is also on record that in 1756 Kennersley, of Boston, suggested to the celebrated Franklin that “as water is a conductor as well as metals, it is to be considered whether a river or a lake, or sea may not be made part of the circuit through which the electric fire passes instead of a circuit all of wire.”