The Idea.

Alexander Graham Bell (1847-1922), who suffered from deafness, was interested in devising a form of "visible speech" for the deaf, first in the form of a universal alphabet and later by mechanical means. The telephone is scientifically uncomplicated: when the sound of a voice vibrates through an iron diaphragm, it changes the electromagnetic field in such a way as to reproduce the vibrations in an electric current. These vibrations are then transformed back into sound through a receiving diaphragm.

The Inventors.

Several inventors were aware of how to make a telephone. By the time Bell applied for a patent on his "harmonic multiple telegraph" (as he called it), other inventors, including Thomas Alva Edison, Elisha Gray, and Amos Dolbeare, were also close to producing functioning instruments. To head off Edison, whom Western Union had engaged to proceed at full speed...