Pleasant Ways in Science

by Richard A. Proctor

Fig. 10.

Fig. 11.

But now we must turn to the greatest marvel of all—the transmission of tones, tunes, and words by the electric wire.

The transmission of the rhythm of an air is of course a very simple matter. I have seen the following passage from “Lardner’s Museum of Science and Art,” 1859, quoted as describing an anticipation of the telephone, though in reality it only shows what every one who has heard a telegraphic indicator at work must have noticed, that the click of the instrument may be made to keep time with an air. “We were in the Hanover Street Office, when there was a pause in the business operations. Mr. M. Porter, of the office at Boston—the writer being at New York—asked what tune we would have? We replied, ‘Yankee Doodle,’ and to our surprise he immediately complied with our request. The instrument, a Morse one, commenced drumming the notes of the tune as perfectly and distinctly as a skilful drummer could have made them at the head of a regiment, and many will be astonished to hear that ‘Yankee Doodle’ can travel by lightning.... So perfectly and distinctly were the sounds of the tunes transmitted, that good instrumental performers could have no difficulty in keeping time with the instruments at this end of the wires.... That a pianist in London should execute a fantasia at Paris, Brussels, Berlin, and Vienna, at the same moment, and with the same spirit, expression, and precision as if the instruments at these distant places were under his fingers, is not only within the limits of practicability, but really presents no other difficulty than may arise from the expense of the performances. From what has just been stated, it is clear that the time of music has been already transmitted, and the production of the sounds does not offer any more difficulty than the printing of the letters of a despatch.” Unfortunately, Lardner omitted to describe how this easy task was to be achieved.

Reuss first in 1861 showed how a sound can be transmitted. At the sending station, according to his method, there is a box, into which, through a pipe in the side, the note to be transmitted is sounded. The box is open at the top, and across it, near the top, is stretched a membrane which vibrates synchronously with the aerial vibrations corresponding to the note. At the middle of the membrane, on its upper surface, is a small disc of metal, connected by a thin strip of copper with the positive pole of the battery at the transmitting station. The disc also, when the machine is about to be put in use, lightly touches a point on a metallic arm, along which (while this contact continues) the electric current passes to the wire communicating with the distant station. At that station the wire is carried in a coil round a straight rod of soft iron suspended horizontally in such a way as to be free to vibrate between two sounding-boards. After forming this coil, the wire which conveys the current passes to the earth-plate and so home. As already explained, while the current passes, the rod of iron is magnetized, but the rod loses its magnetization when the current ceases.

Now, when a note is sounded in the box at the transmitting station, the membrane vibrates, and at each vibration the metal disc is separated from the point which it lightly touches when at rest. Thus contact is broken at regular intervals, corresponding to the rate of vibration due to the note. Suppose, for instance, the note C is sounded; then there are 256 complete vibrations in a second, the electric current is therefore interrupted and renewed, and the bar of soft iron magnetized and demagnetized, 256 times in a second. Now, it had been discovered by Page and Henry that when a bar of iron is rapidly magnetized and demagnetized, it is put into vibrations synchronizing with the interruptions of the current, and therefore emits a note of the same tone as that which has been sounded into the transmitting box.

Professor Heisler, in his “Lehrbuch der technischen Physik,” 1866, wrote of Reuss’s telephone: “The instrument is still in its infancy; however, by the use of batteries of proper strength, it already transmits not only single musical tones, but even the most intricate melodies, sung at one end of the line, to the other, situated at a great distance, and makes them perceptible there with all desirable distinctness.” Dr. Van der Weyde, of New York, states that, after reading an account of Reuss’s telephone, he had two such instruments constructed, and exhibited them at the meeting of the Polytechnic Club of the American Institute. “The original sounds were produced at the furthest extremity of the large building (the Cooper Institute), totally out of hearing of the Association; and the receiving instrument, standing on the table in the lecture-room, produced, with a peculiar and rather nasal twang, the different tunes sung into the box at the other end of the line; not powerfully, it is true, but very distinctly and correctly. In the succeeding summer I improved the form of the box, so as to produce a more powerful vibration of the membrane. I also improved the receiving instrument by introducing several iron wires into the coil, so as to produce a stronger vibration. I submitted these, with some other improvements, to the meeting of the American Association for the Advancement of Science, and on that occasion (now seven years ago) expressed the opinion that the instrument contained the germ of a new method of working the electric telegraph, and would undoubtedly lead to further improvements in this branch of science.”

The telephonic successes recently achieved by Mr. Gray were in part anticipated by La Cour, of Copenhagen, whose method may be thus described: At the transmitting station a tuning-fork is set in vibration. At each vibration one of the prongs touches a fine strip of metal completing a circuit. At the receiving station the wire conveying the electric current is coiled round the prongs of another tuning-fork of the same tone, but without touching them. The intermittent current, corresponding as it does with the rate of vibration proper to the receiving fork, sets this fork in vibration; and in La Cour’s instrument the vibrations of the receiving fork were used to complete the circuit of a local battery. His object was not so much the production of tones as the use of the vibrations corresponding to different tones, to act on different receiving instruments. For only a fork corresponding to the sending fork could be set in vibration by the intermittent current resulting from the latter’s vibrations. So that, if there were several transmitting forks, each could send its own message at the same time, each receiving fork responding only to the vibrations of the corresponding transmitting fork. La Cour proposed, in fact, that his instrument should be used in combination with other methods of telegraphic communication. Thus, since the transmitting fork, whenever put in vibration, sets the local battery of the receiving station at work, it can be used to work a Morse instrument, or it could work an ordinary Wheatstone and Cook instrument, or it could be used for a pantelegraph. The same wire, when different forks are used, could work simultaneously several instruments at the receiving station. One special use indicated by La Cour was the adaptation of his system to the Caselli pantelegraph, whereby, instead of one style, a comb of styles might be carried over the transmitting and recording plates. It would be necessary, in all such applications of his method (though, strangely enough, La Cour’s description makes no mention of the point), that the vibrations of the transmitting fork should admit of being instantly stopped or “damped.”

Mr. Gray’s system is more directly telephonic, as aiming rather at the development of sound itself than at the transmission of messages by the vibrations corresponding to sound. A series of tuning-forks are used, which are set in separate vibration by fingering the notes of a key-board. The vibrations are transmitted to a receiving instrument consisting of a series of reeds, corresponding in note to the series of transmitting forks, each reed being enclosed in a sounding-box. These boxes vary in length from two feet to six inches, and are connected by two wooden bars, one of which carries an electro-magnet, round the coils of which pass the currents from the transmitting instrument. When a tuning-fork is set in vibration by the performer at the transmitting key-board, the electro-magnet is magnetized and demagnetized synchronously with the vibrations of the fork. Not only are vibrations thus imparted to the reed of corresponding note, but these are synchronously strengthened by thuds resulting from the lengthening of the iron when magnetized.

So far as its musical capabilities are concerned, Gray’s telephone can hardly be regarded as fulfilling all the hopes that have been expressed concerning telephonic music. “Dreaming enthusiasts of a prophetic turn of mind foretold,” we learn, “that a time would come when future Pattis would sing on a London stage to audiences in New York, Berlin, St. Petersburg, Shanghai, San Francisco, and Constantinople all at once.” But the account of the first concert given at a distance scarcely realizes these fond expectations. When “Home, Sweet Home,” played at Philadelphia, came floating through the air at the Steinway Hall, New York, “the sound was like that of a distant organ, rather faint, for a hard storm was in progress, and there was consequently a great leakage of the electric current, but quite clear and musical. The lower notes were the best, the higher being sometimes almost inaudible. ‘The Last Rose of Summer,’ ‘Com’ è gentil,’ and other melodies, followed, with more or less success. There was no attempt to play chords,” though three or four notes can be sounded together. It must be confessed that the rosy predictions of M. Strakosch (the impresario) “as to the future of this instrument seem rather exalted, and we are not likely as yet to lay on our music from a central reservoir as we lay on gas and water, though the experiment was certainly a very curious one.”