Antonio Meucci - Invention of The Telephone

Invention of The Telephone

There exists much dispute over who deserves priority as the first inventor of the telephone, although Bell was credited with being the first to transmit articulate speech by undulatory currents of electricity.

An Italian researcher in telecommunications, engineer Basilio Catania, and the Federazione Italiana di Elettrotecnica have devoted a Museum to Antonio Meucci making a chronology of his inventing the telephone and tracing the history of the two trials opposing Meucci and Bell. They both support the claim that Antonio Meucci was the real inventor of the telephone However, some scholars outside of Italy do not recognize the claims that Meucci's device had any bearing on the development of the telephone. Tomas Farley also writes that, "Nearly every scholar agrees that Bell and Watson were the first to transmit intelligible speech by electrical means. Others transmitted a sound or a click or a buzz but our boys were the first to transmit speech one could understand."

In 1834 Meucci constructed a kind of acoustic telephone as a way to communicate between the stage and control room at the theatre "Teatro della Pergola" in Florence. This telephone was constructed on the model of pipe-telephones on ships and is still functional.

In 1848 Meucci developed a popular method of using electric shocks to treat rheumatism. He used to give his patients two conductors linked to 60 Bunsen batteries and ending with a cork. He also kept two conductors linked to the same Bunsen batteries. He used to sit in his laboratory, while the Bunsen batteries were placed in a second room and his patients in a third room. In 1849 while providing a treatment to a patient with a 114V electrical discharge, in his laboratory Meucci is claimed to have heard his patient's scream through the piece of copper wire that was between them, from the conductors he was keeping near his ear. His intuition was that the "tongue" of copper wire was vibrating just like a leave of an electroscope; which means that there was an electrostatic effect. In order to continue the experiment without hurting his patient, Meucci covered the copper wire with a piece of paper. Through this device he claimed hearing an inarticulated human voice. He called this device "telegrafo parlante" (lit. "talking telegraph").

On the basis of this prototype, Meucci is claimed to have worked on more than 30 kinds of telephone. In the beginning he was inspired by the telegraph. Differently from other pioneers of the telephone, such as Charles Bourseul, Philipp Reis, Innocenzo Manzetti and others, he did not think about transmitting voice by using the principle of the telegraph key (in scientific jargon, the "make-and-break" method), but he looked for a "continuous" solution, which means without interrupting the electric flux.

In 1856 Meucci is claimed to have constructed the first electromagnetic telephone, made of an electromagnet with a nucleus in the shape of a horseshoe bat, a diaphragm of animal skin, stiffened with potassium dichromate and keeping a metal disk stuck in the middle. The instrument was hosted in a cylindrical carton box. He purportedly constructed this as a way to connect his second-floor bedroom to his basement laboratory, and thus communicate with his wife who was an invalid.

Meucci separated the two directions of transmission in order to eliminate the so-called "local effect", adopting what we would call today a 4-wire-circuit. He constructed a simple calling system with a telegraphic manipulator which short-circuited the instrument of the calling person, producing in the instrument of the called person a succession of impulses (clicks), much more intense than those of normal conversation. As he was aware that his device required a bigger band than a telegraph, he found some means to avoid the so-called "skin effect" through superficial treatment of the conductor or by acting on the material (copper instead of iron). He said he used insulated copper wire.

In 1864 Meucci is claimed to have produced his "best device", using an iron diaphragm with optimized thickness and tightly clamped along its rim. The instrument was housed in a shaving-soap box, whose cover clamped the diaphragm.

In August 1870, Meucci is claimed to have obtained transmission of articulate human voice at a mile distance by using as a conductor a copper wire insulated by cotton. He called his device "telettrofono". Drawings and notes by Antonio Meucci claimed to be dated 27 September 1870 show that Meucci understood inductive loading on long distance telephone lines 30 years before any other scientists. The painting made by Nestore Corradi in 1858 mentions the sentence "Electric current from the inductor pipe".

It was additionally claimed that about 1873 Bill Carroll from Boston, who had heard news about Meucci's invention, asked him to construct a device to allow divers to communicate with people on the surface. In Meucci's drawing, this device appears to be an electromagnetic telephone, encapsulated to make it waterproof.