Not a single element of romance was lacking in Bell's experience; his great invention even involved the love story of his life.

Two influential citizens of Boston, Thomas Sanders and Gardiner G.
Hubbard, had daughters who were deaf and dumb, and both engaged Bell's services as teacher.

Bell lived in Sanders's home for a considerable period, dividing his time between teaching his little pupil how to talk and puttering away at a proposed invention which he called a "harmonic telegraph." Both Sanders and Hubbard had become greatly interested in this contrivance and backed Bell financially while he worked.

It was Bell's idea that, by a system of tuning different telegraphic receivers to different pitches, several telegraphic messages could be sent simultaneously over the same wire.

The idea was not original with Bell, although he supposed that it was and was entirely unaware that, at the particular moment when he started work, about twenty other inventors were struggling with the same problem.