In the 1870s, two famous inventors, Alexander Graham Bell and Elisha Gray, separately created devices to send sound through electrical cables. They both submitted their inventions to the patent office within a few hours of each other, sparking a heated legal dispute over the telephone’s invention, which Bell eventually won.
The telegraph and telephone have similar concepts, and Bell’s success with the telephone stemmed from his efforts to improve the telegraph.
Before Bell’s experiments, the telegraph had been a successful communication system for about 30 years but could only send and receive one message at a time using Morse code. Bell, with his understanding of sound and music, envisioned the possibility of transmitting multiple messages simultaneously along the same wire. He proposed the “Harmonic Telegraph,” based on the idea that different musical notes could be sent down the same wire simultaneously if they had different pitches.
By late 1874, Bell had progressed in his experiment, sharing the potential of multiple telegraphs with close family members. Bell’s future father-in-law, attorney Gardiner Green Hubbard, recognized an opportunity to challenge the Western Union Telegraph Company‘s monopoly. He provided financial support for Bell’s work on multiple telegraphs. However, Bell didn’t mention his and his partner Thomas Watson’s side project — developing a device to electrically transmit the human voice.
Despite initially focusing on the harmonic telegraph, Bell and Watson, spurred on by Hubbard and other backers, continued their work. In March 1875, Bell met Joseph Henry, the director of the Smithsonian Institution, unknowingly through Hubbard. Encouraged by Henry’s positive feedback, Bell and Watson pursued their work with greater enthusiasm. By June 1875, they were close to achieving their goal of creating a device to transmit speech electrically. Their experiments had shown that different tones could vary the strength of an electric current in a wire.