He investigated whether electricity could propagate through space just as light did, without the support of a conductive material. In 1860, he created the first prototype of what he called a "telephone", which could cover a distance of 100 meters. Reis's loudspeaker worked by Magnetotriction (property of magnetic materials that causes them to change shape when they are in the presence of a magnetic field) and its receiver was a coil with wire around an iron needle of a loom and leaning against the violin hole As electrical current passed through the needle, the wire contracted and contact was made. It was very insensitive and produced a very weak sound signal, but of acceptable quality. In addition, a very high voltage was necessary.
It was patented that his instrument was not only limited to emitting musical notes, since Reis, to prove that his voice could be successfully recognized from the other side, introduced a phrase in German that was difficult to understand acoustically that said: “The horse does not eat salad of cucumber”.
He had great difficulty getting his discovery taken seriously in Germany. He presented it on October 26, 1861 before the Physical Association of Frankfurt am Main and, in 1862, he even showed it to Wilhem von Legat, inspector of the Royal Prussian Telegraph Corps, who wrote a description of it, which, curiously, Thomas Alva Edison used in 1875 to develop his carbon microphone.
Reis was only partially successful because he could transmit continuous musical notes, but produced incomprehensible words.
In 1947, the invention was tested by the British company Standard Telephones and Cables (STC) and they confirmed that it could weakly transmit and receive voice. At the time, STC was in talks with Alexander Graham Bell's American Telephone and Telegraph Company and they decided to hide said results in order to maintain Bell's reputation.
The controversy over the invention of the telephone is served, in addition to Reis and Bell, many others claimed to be authors of its invention. It was one of the oldest patent interference cases in the United States and involved Bell, Edison, Elisha Grey, Emil Berliner, Amos Dolbear, JW McDonagh, GB Richmond, WL Voeker, JH Irwin, and Francis Blake Jr. Finally, on 27 The February 1901 ruling was decided in Bell's favor, and the Bell Telephone Company prevailed in this crucial decision, as well as in each of the more than 600 pending cases related to the invention of the telephone.
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