DBP 1961 373 100 Jahre Telefon von Philipp Reis

The Reis telephone was an invention named after

Philipp Reis Johann Philipp Reis (; 7 January 1834 – 14 January 1874) was a self-taught German scientist and inventor. In 1861, he constructed the first ''make-and-break'' telephone, today called the Reis telephone. Early life and education Reis ...

of a

telephone A telephone is a telecommunications device that permits two or more users to conduct a conversation when they are too far apart to be easily heard directly. A telephone converts sound, typically and most efficiently the human voice, into e ...

-like device he constructed. Reis's first successful work is dated to October 1861.

History

In 1861, Philipp Reis succeeded in creating a device that captured sound, converted it to electrical impulses which were transmitted via electrical wires to another device that transformed these pulses into recognizable sounds similar to the original acoustical source. Reis coined the term ''telephon'' to describe his device. In 1862, Reis demonstrated his telephone to Wilhelm von Legat, Inspector of the Royal Prussian Telegraph Corps who produced an account of it (Legat, 1862), a translation of which was obtained by

Thomas Edison Thomas Alva Edison (February 11, 1847October 18, 1931) was an American inventor and businessman. He developed many devices in fields such as electric power generation, mass communication, sound recording, and motion pictures. These inventi ...

in 1875 and which was used in Edison's successful development of the

carbon microphone The carbon microphone, also known as carbon button microphone, button microphone, or carbon transmitter, is a type of microphone, a transducer that converts sound to an electrical audio signal. It consists of two metal plates separated by gra ...

. The Legat account included drawings that are different from that below, suggesting that it is of a later version. Edison acknowledged his debt to Reis thus:

The first inventor of a telephone was Phillip Reis of Germany only musical not articulating. The first person to publicly exhibit a telephone for transmission of articulate speech was A. G. Bell. The first practical commercial telephone for transmission of articulate speech was invented by myself. Telephones used throughout the world are mine and Bell's. Mine is used for transmitting. Bell's is used for receiving.

Microphone

As Reis was considering his invention as a means of broadcasting music, he termed his microphone the 'singing station'. The Reis microphone was based on a horizontal

parchment Parchment is a writing material made from specially prepared untanned skins of animals—primarily sheep, calves, and goats. It has been used as a writing medium for over two millennia. Vellum is a finer quality parchment made from the skins ...

diaphragm as a sound transducer. The diaphragm was mounted on the top of a closed wooden sound box, with a speaking horn on the front. Sound received by the horn caused the diaphragm to vibrate. Above this were two brass strips, later with two platinum contacts, originally with a single platinum contact and the lower contact formed of a drop of mercury in a recess in the end of the screw. One strip was glued to the centre of the diaphragm; another strip, usually two strips in a V, was mounted above this. The strip's own weight gave a light pressure between the contacts. Sound vibrations caused the diaphragm and lower contact to vibrate in sympathy. This changed the resistance between the two contacts, giving an electrical signal to the telephone line.

Patent dispute

There was some question as to the operation of the microphone. It is regarded today as having varied the ''resistance'' of the contacts. However Reis's own description claimed that the contacts opened and closed. At the time, it was held that a circuit with such a 'make and break' circuit was incapable of transmitting intelligible speech. Reis's device had been used to transmit speech from 1861, and widely publicly demonstrated from 1863, yet when Bell's patent claim was set against Reis's primacy of inventing the telephone this 'inability' for it to work because of its use of a "false theory" was enough to (legally) portray Reis's invention as invalid, thus allowing Bell to claim novelty.

Loudspeaker

Reis's speaker worked by

magnetostriction Magnetostriction (cf. electrostriction) is a property of magnetic materials that causes them to change their shape or dimensions during the process of magnetization. The variation of materials' magnetization due to the applied magnetic field chan ...

. In his first receiver he wound a coil of wire around an iron knitting needle and rested the needle against the F hole of a violin. As current passed through the needle, the iron ''shrank'' and a click was produced. The image, below, shows an advanced version where the iron bar is clamped to a cigar-box-shaped

resonator A resonator is a device or system that exhibits resonance or resonant behavior. That is, it naturally oscillates with greater amplitude at some frequencies, called resonant frequencies, than at other frequencies. The oscillations in a resonator ...

. This receiver is not very sensitive. It produces weak sound but has good

fidelity Fidelity is the quality of faithfulness or loyalty. Its original meaning regarded duty in a broader sense than the related concept of ''fealty''. Both derive from the Latin word ''fidēlis'', meaning "faithful or loyal". In the City of London fin ...

. It requires very high current and is a

current Currents, Current or The Current may refer to: Science and technology * Current (fluid), the flow of a liquid or a gas ** Air current, a flow of air ** Ocean current, a current in the ocean *** Rip current, a kind of water current ** Current (stre ...

-sensitive device rather than a

voltage Voltage, also known as electric pressure, electric tension, or (electric) potential difference, is the difference in electric potential between two points. In a static electric field, it corresponds to the work needed per unit of charge to ...

-sensitive device. This instrument could transmit continuous musical tones but produced indistinct speech. In 1865, however, British scientist David E. Hughes used the Reis telephone with "good results".

References

* Legat, V. 1862
"Reproducing Sounds on Extra Galvanic Way"
accessed 26 March 2006. * Friedrich Georg Wieck, Otto Wilhelm Ålund "''Uppfinningarnas bok''" vol. II, 1874. * Thompson, Sylvanus P. "''Philipp Reis, Inventor of the Telephone''" London: E. & F.N. Spon, 1883. * Coe, Lewis "''The Telephone and Its Several Inventors: A History''" Chapter 2, McFarland & Co, 1995.

External links