top of page

Who invented the telephone?
It's widely recognized that Alexander Graham Bell invented the telephone. Unless you're aware that Elisha Gray, Antonio Meucci, Johann Philipp Reis, Amos Dolbear and others also may have invented it. Thomas Edison was an important contributor to early telephone technologies. Ever since that same day in February 1876 when both Bell and Gray submitted competing patent documents to the U.S. Patent Office, debates have persisted regarding the paternity of the telephone.
The question is not easy to answer. There have been some 600 legal cases (Beauchamp) related to the invention. Bell was the victor in the cases that mattered. Who invented the telephone has as much to do with patents, lawyers, political maneuvering, and intrigue as with inventors. See [Aitken] for a wonderful logical development of the main players and related controversies.
Gray's Caveat
On February 14, 1876, Gray signed and submitted a Caveat document that described a telephone that used a liquid transmitter. A Caveat was similar to a patent application with figures and a detailed description but with no request for an examination. So, in some ways Gray's submission was considered of lesser stature than Bell's full patent application.
Which document arrived first is contentious and has fueled numerous discussions and legal battles over the years, with both sides presenting compelling arguments and evidence in support of their claims. Gray's assertion was not without its supporters, but Bell's patent ultimately secured his place in history.
Fig 1 (upper) is an image from Gray's notebook. It is similar to a drawing in one of Bell's notebooks (lower). Liquid-based transmitters were among several early methods to convert sound waves to electrical signals.
Comparing Gray and Bell's methods

Fig 1, Liquid transmitters from Gray and Bell, 1876 [Hounshell]
The text below is from [Hounshell] and describes Fig 1.
Striking parallels between the telephones envisioned by Elisha Gray and Alexander Graham Bell are evident in their respective sketches of the instruments. Both Gray's transmitter (top) and Bell's (bottom) depended on varying the resistance to the flow of current from a battery.
Both variations would be caused by the vertical movement of a needle in a liquid (electrolyte) bath; the motion would be due to the response of a diaphragm to the sound waves of the human voice. In Gray's transmitter the variation in resistance would depend on changes in the distance between the tip of the needle and the bottom electrode.
In Bell's the variation would depend on the changes in the area of the wedge-shaped needle tip immersed in the bath. The varying current would then pass through an electromagnet (right) at the receiving end of the circuit; variations in the magnetic field would cause a second diaphragm (in Gray's scheme) or a metal reed (in Bell's) to vibrate, thereby reproducing the sound waves that actuated the transmitter.
Gray made the sketch of his device on February 11, 1876, some two months after he conceived the idea. Bell made his sketch on March 9, 24 days after filing his patent application.

Fig A2, portrait of Elisha Gray (NIHF)
For more on the telephone see the article on transmitters.
References
Aitken, William, Who Invented the Telephone, 1939
Beauchamp, Christopher, Invented by Law: Alexander Graham Bell and the Patent That Changed America, 2015.
Hounshell, David, Two Paths to the Telephone, Scientific American, Vol. 244, January 1981
Meszar, J., The New Splendor of Switching, Bell Laboratories Record, Nov 1953
bottom of page