Elisha Gray - Elisha Gray and The Telephone

Elisha Gray and The Telephone

Further information: Elisha Gray and Alexander Bell telephone controversy

Because of Samuel White's opposition to Gray working on the telephone, Gray did not tell anybody about his new invention for transmitting voice sounds until February 11, 1876 (Friday). Gray requested that his patent lawyer William D. Baldwin prepare a "caveat" for filing at the US Patent Office. A caveat was like a provisional patent application with drawings and description but without a request for examination.

On Monday morning February 14, 1876 Gray signed and had notarized the caveat that described a telephone that used a liquid microphone. Baldwin then submitted the caveat to the US Patent Office. That same morning a lawyer for Alexander Graham Bell submitted Bell's patent application.

Which application arrived first is hotly disputed, although Gray believed that his caveat arrived a few hours before Bell's application. Bell's lawyers in Washington, DC had been waiting with Bell's patent application for months, under instructions not to file it in the USA until it had been filed in Britain first. (At the time, Britain would only issue patents on discoveries not previously patented elsewhere.)

According to Evenson, during the weekend of February 12–14, 1876, before either caveat or application had been filed in the patent office, Bell's lawyer learned about the liquid transmitter idea in Gray's caveat that would be filed early Monday morning February 14. Bell's lawyer then added seven sentences describing the liquid transmitter and a variable resistance claim to Bell's draft application. After the lawyer's clerk recopied the draft as a finished patent application, Bell's lawyer hand-delivered the finished application to the patent office just before noon on Monday, a few hours after Gray's caveat was delivered to the patent office by Gray's lawyer. Bell's lawyer requested that Bell's application be immediately recorded and hand-delivered to the examiner on Monday so that later Bell could claim it had arrived first. Bell was in Boston at this time and was not aware that his application had been filed in the US patent office.

Five days later, on February 19, Zenas Fisk Wilber, the patent examiner for both Bell's application and Gray's caveat, noticed that Bell's application claimed the same variable resistance feature described in Gray's caveat. Wilber suspended Bell's application for 90 days to give Gray time to submit a competing patent application. The suspension also gave Bell time to amend his claims to avoid an interference with an earlier patent application of Gray's that mentioned changing the intensity of the electric current without breaking the circuit, which seemed to the examiner to be an "undulatory current" that Bell was claiming. Such an interference would delay Bell's application until Bell submitted proof, under the first to invent rules, that Bell had invented that feature before Gray.

Bell's lawyer telegraphed Bell, who was still in Boston, to come to Washington DC. When Bell arrived on February 26, Bell visited his lawyers and then visited examiner Wilber who told Bell that Gray's caveat showed a liquid transmitter and asked Bell for proof that the liquid transmitter idea (described in Bell's patent application as using mercury as the liquid) was invented by Bell. Bell pointed to an application of Bell's filed a year earlier where mercury was used in a circuit breaker. The examiner accepted this argument, although mercury would not have worked in a telephone transmitter. On February 29, Bell's lawyer submitted an amendment to Bell's claims that distinguished over Gray's caveat and Gray's earlier application. On March 3, Wilber approved Bell's application and on March 7, 1876 patent 174,465 was published by the U.S. Patent Office.

Bell returned to Boston and resumed work on March 9, drawing a diagram in his lab notebook of a water transmitter being used face down and very similar to that shown in Gray's caveat." Bell and Watson built and tested Gray's water transmitter design on March 10 and successfully transmitted clear speech saying "Mr. Watson – come here – I want to see you." Bell's notebooks did not become public until the 1990s.

The importance of Bell's test of Gray's water transmitter idea was it proved that clear speech could be transmitted electrically. It was a scientific experiment, not development of a commercial product. Prior to that, Bell had only an unproven theory.

Although Gray had abandoned his caveat, Gray applied for a patent for the same invention in late 1877. This put him in a second interference with Bell's patents. The Patent Office determined "while Gray was undoubtedly the first to conceive of and disclose the invention, as in his caveat of 14 February 1876, his failure to take any action amounting to completion until others had demonstrated the utility of the invention deprives him of the right to have it considered." Gray challenged Bell's patent anyway, and after two years of litigation, Bell was awarded rights to the invention, and as a result, Bell is credited as the inventor.

In 1886, the patent examiner (Zenas Fisk Wilber) stated in a sworn affidavit that he was an alcoholic and deeply in debt to Bell's lawyer Marcellus Bailey with whom Wilber had served in the Civil War. Wilber stated that, contrary to Patent Office rules, he showed Bailey the caveat Gray had filed. Wilber also stated that he showed the caveat to Bell and Bell gave him $100. Bell testified that they only discussed the patent in general terms, although in a letter to Gray, Bell admitted that he learned some of the technical details.

Bell's patent was also disputed in 1888 by attorney Lysander Hill who accused Wilber of allowing Bell or his lawyer Pollok to add a handwritten margin note of seven sentences to Bell's application that describe an alternate design similar to Gray's liquid microphone design. However, the marginal note was added only to Bell's earlier draft, not as a marginal addition to his patent application that shows the seven sentences already present in a paragraph in Bell's patent application when it was filed in the Patent Office on February 14, 1876. Bell testified that he added those seven sentences in the margin of an earlier draft of his application "almost at the last moment before sending it off to Washington" to his lawyers. Bell or his lawyer could not have added the seven sentences to the application after it was filed in the Patent Office, because then there would not have been any 90 day suspension of Bell's application on February 19.

Although Bell was accused, and is still accused, of stealing the telephone from Gray, Bell used Gray's water transmitter design only after Bell's patent was granted and only as a proof of concept scientific experiment to prove to his own satisfaction that intelligible "articulate speech" (Bell's words) could be electrically transmitted. Bell's assistant Thomas Watson testified that he tested all of the competing designs. After March 1876, Bell and Watson focused on improving the electromagnetic telephone and never used Gray's liquid transmitter in public demonstrations or commercial use. When Bell demonstrated his telephone at the Centennial Exhibition in June 1876, he used his improved electromagnetic transmitter, not Gray's water transmitter.