FIGS. 1 AND 2.—1849.
The apparatus he used for this purpose is shown in Fig. 1. It consists of an oval disk or spatula of copper attached to a wire which was coiled and supported in an insulating handle of cork. To ascertain that he was able to hear the sound, he covered the device with a funnel of pasteboard, shown in the adjoining figure, and held it to his ear, and thought that he heard the sound more distinctly.
These instruments were constructed in 1849 in Havana, where Meucci was mechanical director of a theater. In May, 1851, he came to this country, and settled in Staten Island, where he has lived ever since. It was not until a year later that he again took up his telephonic studies, and then he tried an arrangement somewhat different from the first. He used a tin tube, Figs. 3 and 4, and covered it with wire, the ends of which were soldered to the tongue of copper. With this instrument, he states, he frequently conversed with his wife from the basement of his house to the third floor, where she was confined as an invalid.
FIGS. 3 AND 4.—1852.
Continuing his experiments, he conceived the idea of using a bobbin of wire with a metallic core, and the first instrument he constructed on this idea is shown in Fig. 5. It consisted of a wooden tube and pasteboard mouth piece, and supported within the tube was a bundle of steel wires, surrounded at their upper end by a bobbin of insulated wire. The diaphragm in this instrument, was an animal membrane, and it was slit in a semicircle so as to make a flap or valve which responded to the air vibrations. This was the first instrument in which he used a bobbin, but the articulation naturally left much to be desired, on account of the use of the animal membrane. Meucci fixes the dates from the fact that Garibaldi lived with him during the years 1851-54, and he remembers explaining the principles of his invention to the Italian patriot.
After constructing the instrument just described, Meucci devised another during 1853-54. This consisted of a wooden block with a hole in the center which was filled with magnetic iron ore, and through the center of which a steel wire passed. The magnetic iron ore was surrounded by a coil of insulated copper wire. But an important improvement was introduced here in the shape of an iron diaphragm. With this apparatus greatly improved effects were obtained.
FIG. 5.—1853.
In 1856 Meucci first tried, he says, a horseshoe magnet, as shown in Fig. 6, but he went a step backward in using an animal membrane. He states that this form did not talk so well as some which he had made before, as might be expected.