Alexander Graham Bell (1847–1922) was born in Edinburgh, Scotland, into a family of speech teachers. His father invented Visible Speech, a set of symbols showing how to make each sound. His mother was nearly deaf, and so was his wife, Mabel Hubbard. Bell moved to Canada with his family in 1870 and to Boston in 1871, where he taught deaf students to speak. Sound and hearing were his life's work.
Key idea
The problem
Telegraph companies wanted to send several messages at once on one wire. Bell, like the inventor Elisha Gray and others, worked on a "harmonic telegraph" that would send each message as a different musical note. Bell, who knew how speech is built from many tones together, began to wonder whether a wire could carry all the tones of a voice.
What he tried
Bell worked with a young machinist, Thomas Watson. On June 2, 1875, a reed stuck on Watson's transmitter; when Watson plucked it free, Bell heard the twang come through his receiver, with all its overtones. The changing current from a vibrating reed near a magnet could carry the shape of a sound. Over the next months they built transmitters with a diaphragm to catch the voice.
Bell's patent, U.S. No. 174,465, was filed on February 14, 1876, and granted on March 7. Three days later, using a new transmitter with a needle dipping into acid water, Bell spoke to Watson in the next room. His notebook records it:
I then shouted into M the following sentence: "Mr. Watson—Come here—I want to see you." To my delight he came and declared that he had heard and understood what I said.
Who invented the telephone?
This question has real disagreement, so here are the main positions.
- Bell held the patent, which survived hundreds of lawsuits, including cases decided by the U.S. Supreme Court. He gave the first public demonstrations and built a working system.
- Elisha Gray filed a caveat (a notice of an invention in progress) at the patent office on the same day as Bell's application, describing a liquid transmitter like the one Bell used on March 10. Some historians think Bell learned of Gray's idea; others think the timing was coincidence and Bell's own work led him there.
- Antonio Meucci, an Italian immigrant in New York, built voice-carrying devices years earlier and filed a caveat in 1871, but could not afford to renew it after 1874. His supporters say he was the first inventor; others say his devices did not work the way Bell's did.
Most historians credit Bell with the first practical telephone and the patent, while recognizing that Gray and Meucci did important work toward the same goal. Big inventions often happen to several people at once, because the ideas and parts they need are in the air.
| When | What happened |
|---|---|
| 1847 | Bell born in Edinburgh |
| 1871 | Moves to Boston to teach deaf students |
| 1871 | Meucci files a caveat for a "sound telegraph" |
| June 2, 1875 | The stuck reed: Bell hears a twang with its overtones |
| February 14, 1876 | Bell's patent application and Gray's caveat filed the same day |
| March 7, 1876 | Patent 174,465 granted |
| March 10, 1876 | "Mr. Watson—Come here—I want to see you" |
| 1877 | Bell Telephone Company founded |
| 1915 | Bell and Watson open the first coast-to-coast telephone line |
| 1922 | Bell dies in Nova Scotia |
Worked example: Days apart
- $10 - 7 = 3$.
Answer: 3 days.
What it led to
By 1900 there were well over a million telephones in the United States. Bell spent much of his later life on other projects: hydrofoil boats, kites, a photophone that sent sound on a beam of light, and teaching the deaf, which he always called his true work.
Common mistake
Read more: Alexander Graham Bell and Telephone.