Saturday, November 11, 2006

The telephone

Philipp Reis imagined that electricity could be propagated through space, as light can, without the aid of a material conductor, and he performed some experiments on the subject. The results were described in a paper, "On the Radiation of Electricity," which, in 1859, he posted to Professor Poggendorff; for insertion in the then well-known periodical, Annalen der Physik. The manuscript was declined, to the great disappointment of the sensitive young teacher.
Philipp Reis had studied the organs of hearing, and the idea of an apparatus for transmitting sound by means of electricity had been floating in his mind for years. Incited by his lessons on physics, he attacked the problem, and was rewarded with success. In 1860, he constructed the first prototype of a telephone, covering a distance of 100 m. In 1862 he again tried Poggendorff, with an account of his "Telephon" as he called it; but his second offering was rejected like the first. The learned professor, it seems, regarded the transmission of speech by electricity as a chimera; but Philipp Reis, bitterly, attributed the failure to his being "only a poor schoolmaster."
Reis had difficulty in interesting people in Germany in his invention despite demonstrating it to (among others) Wilhelm von Legat, Inspector of the Royal Prussian Telegraph Corps in 1862 (Legat, 1862). It aroused more interest in the United States In 1872, Prof Vanderwyde demonstrated Reis's device in New York where it was seen by Thomas Edison, and possibly officials of Western Union and Alexander Graham Bell. Bell, Edison and Berliner drew on Reis's device as a starting point in their subsequent development of components of the telephone.

Previous experimenters
Since the invention of the telephone, attention has been called to the fact that, in 1854, M. Charles Bourseul, a French telegraphist, had conceived a plan for conveying sounds and even speech by electricity. "Suppose," he explained, "that a man speaks near a movable disc sufficiently flexible to lose none of the vibrations of the voice; that this disc alternately makes and breaks the currents from a battery: you may have at a distance another disc which will simultaneously execute the same vibrations.... It is certain that, in a more or less distant future, speech will be transmitted by electricity. I have made experiments in this direction; they are delicate and demand time and patience, but the approximations obtained promise a favourable result."
Bourseul deserves the credit of being perhaps the first to devise an electric telephone and try to make it; but Philipp Reis deserves the honor of first realising the idea as a device to transmit and receive sounds electrically.
Bourseul's idea seems to have attracted little notice at the time, and as soon forgotten. Even the Count du Moncel, who was ever ready to welcome a promising invention, evidently regarded it as a fantastic notion. It is very doubtful if Philipp Reis had ever heard of it. He was led to conceive a similar apparatus by a study of the mechanism of the human ear, which he knew to contain a membrane vibrating due to sound waves, and communicating its vibrations through the hammer-bone behind it to the auditory nerve. It therefore occurred to him, that if he made a diaphragm to imitate this membrane and caused it, by vibrating, to make and break the circuit of an electric current, he would be able through the magnetic power of the interrupted current to reproduce the original sounds at a distance.
In 1837–1838 Professor Page, of Massachusetts, had discovered that a needle or thin bar of iron, placed in the hollow of a coil or bobbin of insulated wire, would emit an audible 'tick' at each interruption of a current, flowing in the coil, and that if these separate ticks followed each other fast enough, by a rapid interruption of the current, they would run together into a continuous hum, to which he gave the name of 'galvanic music.' The pitch of this note would correspond to the rate of interruption of the current. These faint sounds are due to magnetostriction. From these and other discoveries which had been made by Noad, Wertheim, Marrian, and others, Philipp Reis knew that if the current which had been interrupted by his vibrating diaphragm were conveyed to a distance by a metallic circuit, and there passed through a coil like that of Page, the iron needle would emit a note like thatwhich had caused the oscillation of the transmitting diaphragm. Acting on this knowledge, he constructed his rudimentary telephone. This prototype is now in the museum of the Reichs Post-Amt, Berlin

Another of his early transmitters was a rough model of the human ear, carved in oak, and provided with a drum which actuated a bent and pivoted lever of platinum, making it open and close a springy contact of platinum foil in the metallic circuit of the current. He devised some ten or twelve different forms, each an improvement on its predecessors, which transmitted music fairly well, and even a word or two of speech with more or less perfection. But the apparatus failed as a practical means of talking to a distance.
The discovery of the microphone by Professor Hughes has enabled us to understand the reason of this failure. The transmitter of Philipp Reis was based on the plan of interrupting the current, and the spring was intended to close the contact after it had been opened by the shock of a vibration. So long as the sound was a musical tone it proved efficient, for a musical tone is a regular succession of vibrations. But the vibrations of speech are irregular and complicated, and in order to transmit them the current has to be varied in strength without being altogether broken. The waves excited in the air by the voice should merely produce corresponding waves in the current. In short, the current ought to undulate in sympathy with the oscillations of the air. The Reis phone was poor at transmitting articulated speech, but conveyed the pitch of the sound.
It appears from the report of Herr Von Legat, inspector of the Royal Prussian Telegraphs, on Philipp Reis' telephone, published in 1862, that the inventor was quite aware of this principle, but his instrument was not well adapted to apply it. No doubt the platinum contacts he employed in the transmitter behaved to some extent as a crude metal microphone, and hence a few words, especially familiar or expected ones, could be transmitted and distinguished at the other end of the line. If Reis' phone was adjusted so that the contact points made a "loose metallic contact" they would be functioning much like the later telepone invented by Berliner or the microphone of Hughes, one form of which had iron nails in loose contact. Thus the Reis phone worked best for speech when it was slightly out of adjustment.
A history of the telephone from 1910 says "In the course of the Dolbear lawsuit, a Reis machine was brought into court, and created much amusement. It was able to squeak, but not to speak. Experts and professors wrestled with it in vain. It refused to transmit one intelligible sentence. '`It can speak, but it won't,' explained one of Dolbear's lawyers. It is now generally known that while a Reis machine, when clogged and out of order, would transmit a word or two in an imperfect way, it was built on wrong lines. It was no more a telephone than a wagon is a sleigh, even though it is possible to chain the wheels and make them slide for a foot or two. Said Judge Lowell, in rendering his famous decision: 'A century of Reis would never have produced a speaking telephone by mere improvement of construction. It was left for Bell to discover that the failure was due not to workmanship but to the principle which was adopted as the basis of what had to be done. . . . Bell discovered a new art -- that of transmitting speech by electricity, and his claim is not as broad as his invention. . . . To follow Reis is to fail; but to follow Bell is to succeed (Casson, p96).'"
But Philipp Reis does not seem to have realised the importance of not entirely breaking the circuit of the current; at all events, his metal spring is not in practice an effective provision against this, for it allows the metal contacts to jolt too far apart, and thus interrupt the current. Had he lived to modify the spring and the form or material of his contacts so as to keep the current continuous — as he might have done, for example, by using carbon for platinum — he would have forestalled alike Bell, Edison, and Hughes in the production of a good speaking telephone. Philipp Reis in fact was trembling on the verge of a great discovery, which was, however, reserved for others.
His experiments were made in a little workshop behind his home at Friedrichsdorff; and wires were run from it to an upper chamber. Another line was erected between the physical cabinet at Garnier's Institute across the playground to one of the classrooms, and there was a tradition in the school that the boys were afraid of creating an uproar in the room for fear that Philipp Reis would hear them with his "telephon".

The new invention was published to the world in a lecture before the Physical Society of Frankfurt on October 26, 1861, and a description, written by himself for the Jahresbericht, a month or two later. It excited a good deal of scientific notice in Germany; models of it were sent abroad, to London, Dublin, Tiflis, and other places. It became a subject for popular lectures, and an article for scientific cabinets.
Reis obtained a brief renown, but the reaction soon set in. The Physical Society of Frankfurt turned its back on the apparatus which had given it lustre. Philipp Reis resigned his membership in 1867; but the Free German Institute of Frankfurt, which elected him an honorary member, also slighted the instrument as a mere "philosophical toy". At first it was a dream, and now it is a plaything. Have we not had enough of that superior wisdom which is another name for stupidity? The dreams of the imagination are apt to become realities, and the toy of today has a knack of growing into the mighty engine of tomorrow.
Reis believed in his invention, even if no one else did; and had he been encouraged by his fellows from the beginning, he might have brought it into a practical shape. But rebuffs had preyed upon his sensitive heart, and he was already stricken with consumption. It is related that, after his lecture on the telephone at Gießen, in 1854, Poggendorff, who was present, invited him to send a description of his instrument to the Annalen. Philipp Reis answered him, "Ich danke Ihnen Sehr, Herr Professor, aber es ist zu spät. Jetzt will ICH ihn nicht schicken. Mein Apparat wird ohne Beschreibung in den Annalen bekannt werden". (Translated, this means "Thank you very much, Professor, but it is too late. I shall not send it now. My apparatus will become known without any writing in the Annalen.)