Antonio Meucci was born on April 13, 1808, in a borough of Florence, Italy. He was the first of 9 children; his father was at times a government clerk, and a member of the local police, and his mother was principally a homemaker.
At the age of 15, he was admitted to Florence Academy of Fine Arts as its youngest student, where he studied chemical and mechanical engineering. In 1834, he constructed a crude telephone system based on the principles of pipe-telephone used on ships. In 1835, he and his wife emigrated to Cuba, and then in April, 1850, they immigrated to the Unites States. They settled in Staten Island, New York, and remained there the rest of their lives. In 1856, he developed a system using electromagnetic voice transmission, but did not seek a patent (or even a Caveat) until 1871.
A patent Caveat was an instrument a bit shy of a patent. It was easier to obtain, less expensive, and simply warned others that a patent was coming. Patent Caveats according to law were “a description of an invention, intended to be patented, lodged in the patent office before the patent was applied for, and operated as a bar to the issue of any patent to any other person regarding the same invention.”
Caveats lasted 1 year, but could be renewed. The U.S. Patent Office would note the subject matter of the Caveat and hold it in confidentiality. If within the year another inventor filed a patent application for a similar invention, the Patent Office notified the holder of the Caveat, who then had 3 months to submit a formal application. Meucci filed his Caveat in 1871, but did not renew it 3 years later.
An original discussion of Meucci’s invention was written in Italian, but a translation is as follows:
It consists of a vibrating diaphragm and an electrified magnet with a spiral wire that wraps around it. The vibrating diaphragm alters the current of the magnet. These alternations of current, transmitted to the other end of the wire, created analogous vibrations of the receiving diaphragm and reproduce the word.
Accompanying the Caveat was a petition that said, in part:
I believe it preferable to have the wire [connecting the two parties to the conversation]of larger area than that ordinarily employed in the electric telegraph, but will experiment on this. Each of these persons holds to his mouth an instrument analogous to a speaking trumpet, in which the word may easily be pronounced, and the sound concentrated upon the wire. Another instrument is also applied to the ears, in order to receive the voice of the opposite party.
It has been noted by some biographers that neither the Caveat nor the explanation of the operation of the system mentions that sound is to be converted to variable electrical conduction in the wire, nor does it say that variable electrical conduction in the wire is to be converted to sound.
However, others claim that Meucci constructed the first electromagnetic telephone in 1856. He constructed an electromagnet with a nucleus in the shape of a horseshoe bat, a diaphragm of animal skin, stiffened with potassium dichromate, that held a metal disk in the middle. The instrument was mounted in a cylindrical carton box.
The system described here is 1 of 2 that at the time were considered promising. In this method, the transmitter apparatus literally generates electricity (the system is called magneto-induction principle). Although the quality of the output was surprisingly good, the volume of the output was very low. In other words, it didn’t work very well. It was, incidentally, this system that was spelled out by Bell in his 1876 patent. It was only in the margin of Bell’s patent application that the second method — the variable resistance method — was mentioned. And there were challenges to that as well, with some saying that the sketches and explanation were added after the patent was filed, and others saying that that information was stolen from the work of other inventors.
The second of the 2 promising systems had to do with a current-carrying wire, and the ability of the system to vary that current. As will be described in our chapter about Bell, 1 end of a wire was dipped into a conductive liquid. If the wire were dipped in deeply, then the overall resistance of the wire and the liquid would be lessened, If the wire were dipped in only a little, then the resistance of the wire/liquid combination would not be lessened. In Bell’s case, the liquid that worked best was a mixture of water and sulphuric acid. The other end of this wire was connected to a diaphragm that would respond to the vibrations of the human voice. So, speaking into the diaphragm would cause the wire to dip more or less into the acid solution. This would change the resistance of the apparatus, and the electrical signal transmitted down the line would vary.
At the other end of the transmission line, the varying current in the line would change an electrical bias being applied to a like diaphragm, and this would cause the vibrating diaphragm to create sound. It was this method — the variable resistance method — that became the most effective in telephones of the day.
Antonio Meucci and his family lived in Staten Island, New York, until his death in 1889. He was 81 years of age.