Did Bell Really Invent the Telephon?

Alexander Graham Bell v. Elisha Gray. This article discusses just how close the patent race was for invention of the telephone. In part:

Presumably, Bell’s device as described in his patent application would not have operated properly whereas Gray’s design as presented in his caveat would have been successful. (Given his reluctance to file a patent application, Bell might have realized the problem with his design.) Moreover, Bell’s first successful transmission of a human voice on March 9, 1876, relied on the use of acid as a liquid transmitter, similar to the transmitter envisioned by Gray but not included in Bell’s patent application.

Bell was awarded the patent rights to the telephone, partly because of the differences between a patent application and a caveat, and the corresponding conviction that he was the first to invent the device. The U.S. patent system awards those who are first-to-invent and not those who are first-to-file, and so Bell’s victory was not simply the result of an earlier filing time. And Bell also was the first to successfully demonstrate his invention.