[SINGING AND TALKING BY TELEGRAPH.]
People are already to a certain extent acquainted through the newspapers with what is called the Telephone, or instrument for transmitting musical sounds to a distance. We wish to say something of this novelty. The conveyance of sound by means of an electric wire, has been practised through the instrumentality of the bell telegraph, used occasionally, though much less frequently than apparatus of a different kind. The signaller does not himself ring a bell, but sets in vibration a bell at the further or receiving end of the wire. The electric current, passing through the wire, acts upon a small magnet, and this in its turn acts upon a small bell or its hammer. By a preconcerted arrangement, one single sound is understood to denote a particular letter or word; two denote another letter or word; three quickly repeated, have a separate meaning; three separated by unequal intervals of silence, another—and so on. The receiver must have a quick ear, and much practice is necessary for a due fulfilment of his duties. Although the plan has an advantage in enabling him to understand a message in the dark as well as in the light, it has more than equivalent disadvantages; among which is the fact that it leaves no permanent record.
But talking by electricity conveying the actual sounds of the voice for many miles—what are we to think of this? And a song—the words, the music, and the actual quality of the singer's voice; does not this seem almost beyond the powers of such a mode of transmission? Who first thought of such a thing is not now known. Very likely, as in most great inventions, the same idea occurred to many persons at different times, but was laid aside because the mode of realising it was not sufficiently apparent.
It was about 1860 that Reis invented a contrivance for employing a stretched membrane vibrating to a particular pitch or note; a contact-piece was adjusted near the membrane; and a series of rapid contacts sent a series of clicks along an electric wire to an electro-magnetic receiver at the other end. But the apparatus could only convey one note or musical sound.
Four or five years ago, Mr Edison, a telegraphic engineer at Newark in New Jersey, made an attempt in this direction. It is known that, in one form of automatic chemico-electric telegraph, signals are recorded by sending an electric current through prepared paper saturated with a chemical agent which changes in colour wherever the current touches it; the paper is moved on equably, and a pen or stylus rests upon it, conveying the impulse received from the electric wire. Mr Edison has tried to devise an arrangement for producing sound as well as discoloration, something for the ear to hear as well as something else for the eye to see. We are not aware whether his experiments have been sufficiently successful to produce a practically useful result.
In 1874, M. La Cour sent audible signals from Fredericia to Copenhagen, by means of a tuning-fork, a contact-piece, a telegraphic wire, and a key to set the fork in vibration.
Mr Elisha Gray appears to have made a more definite advance in this direction. He has transmitted the pianoforte sounds of a concert through the wire of an electric telegraph. The performer played at Philadelphia, to an audience at New York, ninety miles distant. The apparatus may be called a telephonic piano; it transmits the sounds of that instrument, but of no other. Public performances of this kind were given in the early months of the present year. On one evening the instrument was played at Chicago, and the music heard at Milwaukee, eighty-seven miles distant. The Last Rose of Summer, Yankee Doodle, The Sweet By-and-by, and Home, Sweet Home are named as the tunes thus played. On a second occasion the apparatus triumphed over a distance of no less than two hundred and eighty-four miles, from Chicago to Detroit; not much was attempted in actual music, but the sounds were audible at this great distance. Two instruments are required, a transmitter and a receiver. There is a keyboard of two octaves (available therefore only for simple melodies), a tuning bar, an electro-magnet, and an electric circuit. The play on the keys with the fingers produces vibrations, thuds, molecular movements, in rhythmical succession; these are transmitted by the electric wire to the receiving apparatus at the other end. This receiving apparatus is a large sounding-box, on which is mounted an electro-magnet. The box intensifies the sounds by its sonorousness, through the medium of the slight touches which the magnetised iron gives to the box at every expansion or elongation which the electro-magnetism gives it. Delicate experiments have shewn that there is a minute difference in the length of a bar of iron when magnetised and demagnetised; and Mr Gray appears to have taken advantage of this property in causing his magnetised bar to give a succession of taps to the resonant box. We believe that the apparatus requires wholly new setting for each tune. If so, the system bears the same relation to real pianoforte playing as the barrel organ does to the church organ; it does not lend itself to the spontaneous or extempore effusions of the player.
More comprehensive, so far as the scientific descriptions enable us to judge, is Bell's telephone, for the transmission of talk and sing-song as well as of instrumental sounds. If present indications should be really justified by future results, the imagination can scarcely picture the number of practical applications that may ensue. The inventor, Mr Graham Bell, went to America in 1871. He is the son of Mr Alexander Melville Bell, whose system of 'Visible Speech' has attracted a good deal of notice on both sides of the Atlantic. Both father and son have been practically engaged in perfecting a system for teaching the dumb to speak; and Mr Graham Bell set himself the task of accomplishing something which would justify him in saying: 'If I can make a deaf-mute talk, so can I make iron talk.'[A]
Mr Bell, when at Salem in Massachusetts, began to turn his attention to this subject, the telegraphy of sound, or telephony, in 1872; but three years elapsed before the matter assumed such a form as to enable him to send a little musical message through a two-mile wire. Securing his invention by a patent, he gave his first public exhibition of the system in the autumn of 1876. The talk or speaking of an operator at Cambridge, Massachusetts, was heard at Boston, in the ordinary conversational tones. It does not appear that the actual quality or timbre of the voice was distinguishable, but only a voice, speaking certain words. Early in the present year, however, further improvements were made in the apparatus which enabled it to shew even this kind of delicacy; that is, it transmitted not merely the words in sound, but also the tones and inflections of different voices. Singing being, in regard to acoustics, only one variety of speaking, it follows almost as a matter of course that if the apparatus can talk it can also sing. Accordingly, a lady sang The Last Rose of Summer, and was distinctly heard at the distant station; the sounds 'had about the same effect as if the listeners were at the rear of a concert-hall, say a hundred feet from the singer.' The sounds of laughter and applause were similarly transmitted, with the proper rhythm and key or musical pitch. In instrumental music a violin could be distinguished from a violoncello; a test more delicate than would be supposed by many persons.
In all the earlier experiments of Professor Bell, he employed galvanic batteries to produce the current; but these were afterwards dispensed with, and their place supplied by permanent magnets. With this improved arrangement, sounds were conveyed through a wire to a distance of a hundred and forty-three miles, from Boston to North Conway in New Hampshire. Last February a lecture was delivered, on the subject of Telephony, by Professor Bell at Salem, and was audible, word for word, at Boston. In order to shew that the transmission is equally available in both directions, provided the proper apparatus is at both ends, the lecture from Salem to Boston was followed on the same evening by singing and speech-making from Boston to Salem.