There are some leading electricians who enjoy a reputation based partly on their own efforts and partly on those of their paid assistants. Edison, for example, has a large following, who not only work out his ideas, but suggest, improve, and invent of themselves. The master in such a case is able to avail himself of their abilities and magnify his own genius, so to speak. He is not one mind, but the chief of many minds, and absorbs into himself the glory and the work of a hundred willing subjects.

Professor Hughes is not one of these. His fame is entirely self-earned. All that he has accomplished, and he has done great things, has been the labour of his own hand and brain. He is an artist in invention; working out his own conceptions in silence and retirement, with the artist's love and self-absorption. This is but saying that he is a true inventor; for a mere manufacturer of inventions, who employs others to assist him in the work, is not an inventor in the old and truest sense.

Genius, they say, makes its own tools, and the adage is strikingly verified in the case of Professor Hughes, who actually discovered the microphone in his own drawing-room, and constructed it of toy boxes and sealing wax. He required neither lathe, laboratory, nor assistant to give the world this remarkable and priceless instrument.

Having first become known to fame in America, Professor Hughes is usually claimed by the Americans as a countryman, and through some error, the very date and place of his birth there are often given in American publications; but we have the best authority for the accuracy of the following facts, namely that of the inventor himself.

David Edwin Hughes was born in London in 1831. His parents came from Bala, at the foot of Snowdon, in North Wales, and in 1838, when David was seven years old, his father, taking with him his family, emigrated to the United States, and became a planter in Virginia. The elder Mr. Hughes and his children seem to have inherited the Welsh musical gift, for they were all accomplished musicians. While a mere child, David could improvise tunes in a remarkable manner, and when he grew up this talent attracted the notice of Herr Hast, an eminent German pianist in America, who procured for him the professorship of music in the College of Bardstown, Kentucky. Mr. Hughes entered upon his academical career at Bardstown in 1850, when he was nineteen years of age. Although very fond of music and endowered by Nature with exceptional powers for its cultivation, Professor Hughes had, in addition, an inborn liking and fitness for physical science and mechanical invention. This duality of taste and genius may seem at first sight strange; but experience shows that there are many men of science and inventors who are also votaries of music and art. The source of this apparent anomaly is to be found in the imagination, which is the fountain-head of all kinds of creation.

Professor Hughes now taught music by day for his livelihood, and studied science at night for his recreation, thus reversing the usual order of things. The college authorities, knowing his proficiency in the subject, also offered him the Chair of Natural Philosophy, which became vacant; and he united the two seemingly incongruous professorships of music and physics in himself. He had long cherished the idea of inventing a new telegraph, and especially one which should print the message in Roman characters as it is received. So it happened that one evening while he was under the excitement of a musical improvisation, a solution of the problem flashed into his ken. His music and his science had met at this nodal point.

All his spare time was thenceforth devoted to the development of his design and the construction of a practical type-printer. As the work grew on his hands, the pale young student, beardless but careworn, became more and more engrossed with it, until his nights were almost entirely given to experiment. He begrudged the time which had to be spent in teaching his classes and the fatigue was telling upon his health, so in 1853 he removed to Bowlingreen, in Warren Co., Kentucky, where he acquired more freedom by taking pupils.

The main principle of his type-printer was the printing of each letter by a single current; the Morse instrument, then the principal receiver in America, required, on the other hand, an average of three currents for each signal. In order to carry out this principle it was necessary that the sending and receiving apparatus should keep in strict time with each other, or be synchronous in action; and to effect this was the prime difficulty which Professor Hughes had to overcome in his work. In estimating the Hughes' type-printer as an invention we must not forget the state of science at that early period. He had to devise his own governors for the synchronous mechanism, and here his knowledge of acoustics helped him. Centrifugal governors and pendulums would not do, and he tried vibrators, such as piano-strings and tuning-forks. He at last found what he wanted in two darning needles, borrowed from an old lady in the house where he lived. These steel rods fixed at one end vibrated with equal periods, and could be utilised in such a way that the printing wheel could be corrected into absolute synchronism by each signal current.

In 1854, Professor Hughes went to Louisville to superintend the making of his first instrument; but it was unprotected by a patent in the United States until 1855. In that form straight vibrators were used as governors, and a separate train of wheel-work was employed in correcting: but in later forms the spiral governor was adopted, and the printing and correcting is now done by the same action. In 1855, the invention may be said to have become fit for employment, and no sooner was this the case, than Professor Hughes received a telegram from the editors of the New York Associated Press, summoning him to that city. The American Telegraph Company, then a leading one, was in possession of the Morse instrument, and levied rates for transmission of news which the editors found oppressive. They took up the Hughes' instrument in opposition to the Morse, and introduced it on the lines of several companies. After a time, however, the separate companies amalgamated into one large corporation, the Western Union Telegraph Company of to-day. With the Morse, Hughes, and other apparatus in its power, the editors were again left in the lurch.

In 1857, Professor Hughes leaving his instrument in the hands of the Western Union Telegraph Company, came to England to effect its introduction here. He endeavoured to get the old Electric Telegraph Company to adopt it, but after two years of indecision on their part, he went over to France in 1860, where he met with a more encouraging reception. The French Government Telegraph Administration became at once interested in the new receiver, and a commission of eminent electricians, consisting of Du Moncel, Blavier, Froment, Gaugain, and other practical and theoretical specialists, was appointed to decide on its merits. The first trial of the type-printer took place on the Paris to Lyons circuit, and there is a little anecdote connected with it which is worthy of being told. The instrument was started, and for a while worked as well as could be desired; but suddenly it came to a stop, and to the utter discomfiture of the inventor he could neither find out what was wrong nor get the printer to go again. In the midst of his confusion, it seemed like satire to him to hear the commissioners say, as they smiled all round, and bowed themselves gracefully off, 'TRES-BIEN, MONSIEUR HUGHES—TRES-BIEN, JE VOUS FELICITE.' But the matter was explained next morning, when Professor Hughes learned that the transmitting clerk at Lyons had been purposely instructed to earth the line at the time in question, to test whether there was no deception in the trial, a proceeding which would have seemed strange, had not the occurrence of a sham trial some months previous rendered it a prudent course. The result of this trial was that the French Government agreed to give the printer a year of practical work on the French lines, and if found satisfactory, it was to be finally adopted. Daily reports were furnished of its behaviour during that time, and at the expiration of the term it was adopted, and Professor Hughes was constituted by Napoleon III. a Chevalier of the Legion of Honour.

The patronage of France paved the way of the type-printer into almost all other European countries; and the French agreement as to its use became the model of those made by the other nations. On settling with France in 1862, Professor Hughes went to Italy. Here a commission was likewise appointed, and a period of probation—only six months—was settled, before the instrument was taken over. From Italy, Professor Hughes received the Order of St. Maurice and St. Lazare. In 1863, the United Kingdom Telegraph Co., England, introduced the type-printer in their system. In 1865, Professor Hughes proceeded to Russia, and in that country his invention was adopted after six months' trial on the St. Petersburg to Moscow circuit. At St. Petersburg he had the honour of being a guest of the Emperor in the summer palace, Czarskoizelo, the Versailles of Russia, where he was requested to explain his invention, and also to give a lecture on electricity to the Czar and his court. He was there created a Commander of the Order of St. Anne.

In 1865, Professor Hughes also went to Berlin, and introduced his apparatus on the Prussian lines. In 1867, he went on a similar mission to Austria, where he received the Order of the Iron Crown; and to Turkey, where the reigning Sultan bestowed on him the Grand Cross of the Medjidie. In this year, too he was awarded at the Paris Exhibition, a grand HORS LIGNE gold medal, one out of ten supreme honours designed to mark the very highest achievements. On the same occasion another of these special medals was bestowed on Cyrus Field and the Anglo-American Telegraph Company. In 1868, he introduced it into Holland; and in 1869, into Bavaria and Wurtemburg, where he obtained the Noble Order of St. Michael. In 1870, he also installed it in Switzerland and Belgium.

Coming back to England, the Submarine Telegraph Company adopted the type-printer in 1872, when they had only two instruments at work. In 1878 they had twenty of them in constant use, of which number nine were working direct between London and Paris, one between London and Berlin, one between London and Cologne, one between London and Antwerp, and one between London and Brussels. All the continental news for the TIMES and the DAILY TELEGRAPH is received by the Hughes' type-printer, and is set in type by a type-setting machine as it arrives. Further, by the International Telegraph Congress it was settled that for all international telegrams only the Hughes' instrument and the Morse were to be employed. Since the Post Office acquired the cables to the Continent in 1889, a room in St. Martin's-le-Grand has been provided for the printers working to Paris, Berlin, and Rome.

In 1875, Professor Hughes introduced the type-printer into Spain, where he was made a Commander of the Royal and Distinguished Order of Carlos III. In every country to which it was taken, the merits of the instrument were recognised, and Professor Hughes has none but pleasant souvenirs of his visits abroad.

During all these years the inventor was not idle. He was constantly improving his invention; and in addition to that, he had to act as an instructor where-ever he went, and give courses of lectures explaining the principles and practice of his apparatus to the various employees into whose hands it was to be consigned.

The years 1876-8 will be distinguished in the history of our time for a triad of great inventions which, so to speak, were hanging together. We have already seen how the telephone and phonograph have originated; and to these two marvellous contrivances we have now to add a third, the microphone, which is even more marvellous, because, although in form it is the simplest of them all, in its action it is still a mystery. The telephone enables us to speak to distances far beyond the reach of eye or ear, 'to waft a sigh from Indus to the Pole; 'the phonograph enables us to seal the living speech on brazen tablets, and store it up for any length of time; while it is the peculiar function of the microphone to let us hear those minute sounds which are below the range of our unassisted powers of hearing. By these three instruments we have thus received a remarkable extension of the capacity of the human ear, and a growth of dominion over the sounds of Nature. We have now a command over sound such as we have over light. For the telephone is to the ear what the telescope is to the eye, the phonograph is for sound what the photograph is for light, and the microphone finds its analogue in the microscope. As the microscope reveals to our wondering sight the rich meshes of creation, so the microphone can interpret to our ears the jarr of molecular vibrations for ever going on around us, perchance the clash of atoms as they shape themselves into crystals, the murmurous ripple of the sap in trees, which Humboldt fancied to make a continuous music in the ears of the tiniest insects, the fall of pollen dust on flowers and grasses, the stealthy creeping of a spider upon his silken web, and even the piping of a pair of love-sick butterflies, or the trumpeting of a bellicose gnat, like the 'horns of elf-land faintly blowing.'

The success of the Hughes type-printer may be said to have covered its author with titles and scientific honours, and placed him above the necessity of regular employment. He left America, and travelled from place to place. For many years past, however, he has resided privately in London, an eminent example of that modesty and simplicity which is generally said to accompany true genius.

Mechanical invention is influenced to a very high degree by external circumstances. It may sound sensational, but it is nevertheless true, that we owe the microphone to an attack of bronchitis. During the thick foggy weather of November 1877, Professor Hughes was confined to his home by a severe cold, and in order to divert his thoughts he began to amuse himself with a speaking telephone. Then it occurred to him that there might be some means found of making the wire of the telephone circuit speak of itself without the need of telephones at all, or at least without the need of one telephone, namely, that used in transmitting the sounds. The distinguished physicist Sir William Thomson, had lately discovered the peculiar fact that when a current of electricity is passed through a wire, the current augments when the wire is extended, and diminishes when the wire is compressed, because in the former case the resistance of the material of the wire to the passage of the current is lessened, and in the latter case it becomes greater.

Now it occurred to Professor Hughes that, if this were so, it might be possible to cause the air-vibrations of sound to so act upon a wire conveying a current as to stretch and contract it in sympathy with themselves, so that the sound-waves would create corresponding electric waves in the current, and these electric waves, passed through a telephone connected to the wire, would cause the telephone to give forth the original sounds. He first set about trying the effect of vibrating a wire in which a current flowed, to see if the stretching and compressing thereby produced would affect the current so as to cause sounds in a telephone connected up in circuit with the wire—but without effect. He could hear no sound whatever in the telephone. Then he stretched the wire till it broke altogether, and as the metal began to rupture he heard a distinct grating in the telephone, followed by a sharp 'click,' when the wire sundered, which indicated a 'rush' of electricity through the telephone. This pointed out to him that the wire might be sensitive to sound when in a state of fracture. Acting on the hint, he placed the two broken ends of the wire together again, and kept them so by the application of a definite pressure. To his joy he found that he had discovered what he had been in search of. The imperfect contact between the broken ends of the wire proved itself to be a means of transmitting sounds, and in addition it was found to possess a faculty which he had not anticipated—it proved to be sensitive to very minute sounds, and was in fact a rude microphone. Continuing his researches, he soon found that he had discovered a principle of wide application, and that it was not necessary to confine his experiments to wires, since any substance which conducted an electric current would answer the purpose. All that was necessary was that the materials employed should be in contact with each other under a slight but definite pressure, and, for the continuance of the effects, that the materials should not oxidise in air so as to foul the contact. For different materials a different degree of pressure gives the best results, and for different sounds to be transmitted a different degree of pressure is required. Any loose, crazy unstable structure, of conducting bodies, inserted in a telephone circuit, will act as a microphone. Such, for example, as a glass tube filled with lead-shot or black oxide of iron, or 'white bronze' powder under pressure; a metal watch-chain piled in a heap. Surfaces of platinum, gold, or even iron, pressed lightly together give excellent results. Three French nails, two parallel beneath and one laid across them, or better still a log-hut of French nails, make a perfect transmitter of audible sounds, and a good microphone. Because of its cheapness, its conducting power, and its non-oxidisability, carbon is the most select material. A piece of charcoal no bigger than a pin's head is quite sufficient to produce articulate speech. Gas-carbon operates admirably, but the best carbon is that known as willow-charcoal, used by artists in sketching, and when this is impregnated with minute globules of mercury by heating it white-hot and quenching it in liquid mercury, it is in a highly sensitive microphonic condition. The same kind of charcoal permeated by platinum, tin, zinc, or other unoxidisable metal is also very suitable; and it is a significant fact that the most resonant woods, such as pine, poplar, and willow, yield the charcoals best adapted for the microphone. Professor Hughes' experimental apparatus is of an amusingly simple description. He has no laboratory at home, and all his experiments were made in the drawing-room. His first microphones were formed of bits of carbon and scraps of metal, mounted on slips of match-boxes by means of sealing-wax; and the resonance pipes on which they were placed to reinforce the effect of minute sounds, were nothing more than children's toy money boxes, price one halfpenny, having one of the ends knocked out. With such childish and worthless materials he has conquered Nature in her strongholds, and shown how great discoveries can be made. The microphone is a striking illustration of the truth that in science any phenomenon whatever may be rendered useful. The trouble of one generation of scientists may be turned to the honour and service of the next. Electricians have long had sore reasons for regarding a 'bad contact' as an unmitigated nuisance, the instrument of the evil one, with no conceivable good in it, and no conceivable purpose except to annoy and tempt them into wickedness and an expression of hearty but ignominious emotion. Professor Hughes, however, has with a wizard's power transformed this electrician's bane into a professional glory and a public boon. Verily there is a soul of virtue in things evil.

The commonest and at the same time one of the most sensitive forms of the instrument is called the 'pencil microphone,' from the pencil or crayon of carbon which forms the principal part of it. This pencil may be of mercurialised charcoal, but the ordinary gas-carbon, which incrusts the interior of the retorts in gas-works, is usually employed. The crayon is supported in an upright position by two little brackets of carbon, hollowed out so as to receive the pointed ends in shallow cups. The weight of the crayon suffices to give the required pressure on the contacts, both upper and lower, for the upper end of the Pencil should lean against the inner wall of the cup in the upper bracket. The brackets are fixed to an upright board of light, dry, resonant pine-wood, let into a solid base of the same timber. The baseboard is with advantage borne by four rounded india-rubber feet, which insulate it from the table on which it may be placed. To connect the microphone up for use, a small voltaic battery, say three cells (though a single cell will give surprising results), and a Bell speaking telephone are necessary. A wire is led from one of the carbon brackets to one pole of the battery, and another wire is led from the other bracket to one terminal screw of the telephone, and the circuit is completed by a wire from the other terminal of the telephone to the other pole of the battery. If now the slightest mechanical jar be given to the wooden frame of the microphone, to the table, or even to the walls of the room in which the experiment takes place, a corresponding noise will be heard in the microphone. By this delicate arrangement we can play the eavesdropper on those insensible vibrations in the midst of which we exist. If a feather or a camel-hair pencil be stroked along the base-board, we hear a harsh grating sound; if a pin be laid upon it, we hear a blow like a blacksmith's hammer; and, more astonishing than all, if a fly walk across it we hear it tramping like a charger, and even its peculiar cry, which has been likened, with some allowance for imagination, to the snorting of an elephant. Moreover it should not be forgotten that the wires connecting up the telephone may be lengthened to any desired extent, so that, in the words of Professor Hughes, 'the beating of a pulse, the tick of a watch, the tramp of a fly can then be heard at least a hundred miles from the source of sound.' If we whisper or speak distinctly in a monotone to the pencil, our words will be heard in the telephone; but with this defect, that the TIMBRE or quality is, in this particular form of the instrument, apt to be lost, making it difficult to recognise the speaker's voice. But although a single pencil microphone will under favourable circumstances transmit these varied sounds, the best effect for each kind of sound is obtained by one specially adjusted. There is one pressure best adapted for minute sounds, another for speech, and a third for louder sounds. A simple spring arrangement for adjusting the pressure of the contacts is therefore an advantage, and it can easily be applied to a microphone formed of a small rod of carbon pivoted at its middle, with one end resting on a block or anvil of carbon underneath. The contact between the rod and the block in this 'hammer-and-anvil' form is, of course, the portion which is sensitive to sound.

The microphone is a discovery as well as an invention, and the true explanation of its action is as yet merely an hypothesis. It is supposed that the vibrations put the carbons in a tremor and cause them to approach more or less nearly, thus closing or opening the breach between them, which is, as it were, the floodgate of the current.

The applications of the microphone were soon of great importance. Dr. B. W. Richardson succeeded in fitting it for auscultation of the heart and lungs; while Sir Henry Thompson has effectively used it in those surgical operations, such as probing wounds for bullets or fragments of bone, in which the surgeon has hitherto relied entirely on his delicacy of touch for detecting the jar of the probe on the foreign body. There can be no doubt that in the science of physiology, in the art of surgery, and in many other walks of life, the microphone has proved a valuable aid.

Professor Hughes communicated his results to the Royal Society in the early part of 1878, and generously gave the microphone to the world. For his own sake it would perhaps have been better had he patented and thus protected it, for Mr. Edison, recognising it as a rival to his carbon-transmitter, then a valuable property, claimed it as an infringement of his patents and charged him with plagiarism. A spirited controversy arose, and several bitter lawsuits were the consequence, in none of which, however, Professor Hughes took part, as they were only commercial trials. It was clearly shown that Clerac, and not Edison, had been the first to utilise the variable resistance of powdered carbon or plumbage under pressure, a property on which the Edison transmitter was founded, and that Hughes had discovered a much wider principle, which embraced not only the so-called 'semi-conducting' bodies, such as carbon; but even the best conductors, such as gold, silver, and other metals. This principle was not a mere variation of electrical conductivity in a mass of material brought about by compression, but a mysterious variation in some unknown way of the strength of an electric current in traversing a loose joint or contact between two conductors. This discovery of Hughes really shed a light on the behaviour of Edison's own transmitter, whose action he had until then misunderstood. It was now seen that the particles of carbon dust in contact which formed the button were a congeries of minute micro-phones. Again it was proved that the diaphragm or tympanum to receive the impression of the sound and convey it to the carbon button, on which Edison had laid considerable stress, was non-essential; for the microphone, pure and simple, was operated by the direct impact of the sonorous waves, and required no tympanum. Moreover, the microphone, as its name implies, could magnify a feeble sound, and render audible the vibrations which would otherwise escape the ear. The discovery of these remarkable and subtle properties of a delicate contact had indeed confronted Edison; he had held them in his grasp, they had stared him in the face, but not-withstanding all his matchless ingenuity and acumen, he, blinded perhaps by a false hypothesis, entirely failed to discern them. The significant proof of it lies in the fact that after the researches of Professor Hughes were published the carbon transmitter was promptly modified, and finally abandoned for practical work as a telephone, in favour of a variety of new transmitters, such as the Blake, now employed in the United Kingdom, in all of which the essential part is a microphone of hard carbon and metal. The button of soot has vanished into the limbo of superseded inventions.

Science appears to show that every physical process is reciprocal, and may be reversed. With this principle in our minds, we need not be surprised that the microphone should not only act as a TRANSMITTER of sounds, but that it should also act as a RECEIVER. Mr. James Blyth, of Edinburgh, was the first to announce that he had heard sounds and even speech given out by a microphone itself when substituted for the telephone. His transmitting microphone and his receiving one were simply jelly-cans filled with cinders from the grate. It then transpired that Professor Hughes had previously obtained the same remarkable effects from his ordinary 'pencil' microphones. The sounds were extremely feeble, however, but the transmitting microphones proved the best articulating ones. Professor Hughes at length constructed an adjustable hammer-and-anvil microphone of gas-carbon, fixed to the top of a resonating drum, which articulated fairly well, although not so perfectly as a Bell telephone. Perhaps a means of improving both the volume and distinctness of the articulation will yet be forthcoming and we may be able to speak solely by the microphone, if it is found desirable. The marvellous fact that a little piece of charcoal can, as it were, both listen and speak, that a person may talk to it so that his friend can hear him at a similar piece a hundred miles away, is a miracle of nineteenth century science which far transcends the oracles of antiquity.

The articulating telephone was the forerunner of the phonograph and microphone, and led to their discovery. They in turn will doubtless lead to other new inventions, which it is now impossible to foresee. We ask in vain for an answer to the question which is upon the lips of every one-What next? The microphone has proved itself highly useful in strengthening the sounds given out by the telephone, and it is probable that we shall soon see those three inventions working unitedly; for the microphone might make the telephone sounds so powerful as to enable them to be printed by phonograph as they are received, and thus a durable record of telephonic messages would be obtained. We can now transmit sound by wire, but it may yet be possible to transmit light, and see by telegraph. We are apparently on the eve of other wonderful inventions, and there are symptoms that before many years a great fundamental discovery will be made, which will elucidate the connection of all the physical forces, and will illumine the very frame-work of Nature.

In 1879, Professor Hughes endowed the scientific world with another beautiful apparatus, his 'induction balance.' Briefly described, it is an arrangement of coils whereby the currents inducted by a primary circuit in the secondary are opposed to each other until they balance, so that a telephone connected in the secondary circuit is quite silent. Any disturbance of this delicate balance, however, say by the movement of a coil or a metallic body in the neighbourhood of the apparatus, will be at once reported by the induction currents in the telephone. Being sensitive to the presence of minute masses of metal, the apparatus was applied by Professor Graham Bell to indicate the whereabouts of the missing bullet in the frame of President Garfield, as already mentioned, and also by Captain McEvoy to detect the position of submerged torpedoes or lost anchors. Professor Roberts-Austen, the Chemist to the Mint, has also employed it with success in analysing the purity and temper of coins; for, strange to say, the induction is affected as well by the molecular quality as the quantity of the disturbing metal. Professor Hughes himself has modified it for the purpose of sonometry, and the measurement of the hearing powers.

To the same year, 1879, belong his laborious investigations on current induction, and some ingenious plans for eliminating its effects on telegraph and telephone circuits.

Soon after his discovery of the microphone he was invited to become a Fellow of the Royal Society, and a few years later, in 1885 he received the Royal Medal of the Society for his experiments, and especially those of the microphone. In 1881 he represented the United Kingdom as a Commissioner at the Paris International Exhibition of Electricity, and was elected President of one of the sections of the International Congress of Electricians. In 1886 he filled the office of President of the Society of Telegraph Engineers and of Electricians.

The Hughes type-printer was a great mechanical invention, one of the greatest in telegraphic science, for every organ of it was new, and had to be fashioned out of chaos; an invention which stamped its author's name indelibly into the history of telegraphy, and procured for him a special fame; while the microphone is a discovery which places it on the roll of investigators, and at the same time brings it to the knowledge of the people. Two such achievements might well satisfy any scientific ambition. Professor Hughes has enjoyed a most successful career. Probably no inventor ever before received so many honours, or bore them with greater modesty.