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Invention and innovation: An introduction
Invention and innovation: An introduction

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4.2 When and where was the telephone invented?

I'd read in the past that the telephone was invented in 1876 by Alexander Graham Bell. However when I looked more closely at the history it turns out that the idea had been ‘in the air’ for almost half a century.

The distance communication technology of the time, the telegraph, was based on sending pulses of electricity along a wire to control an electromagnet at the receiving end. The sender completed an electric circuit by pressing a key and the receiver's electromagnet controlled a pen that made marks on a moving paper tape. Samuel Morse devised a code whereby the letters of the alphabet could be represented by different combinations of dots and dashes. Later, telegraph operators learned to interpret the Morse code from the sound made by the electromagnet and the paper tape became redundant.

In 1854 Charles Bourseul suggested that speaking close to a diaphragm would cause it to vibrate and that these vibrations could be used to make or break an electrical circuit, as in the telegraph. The process could then be reversed by a receiving diaphragm turning the signal back into speech. Bourseul didn't pursue this idea himself but it was taken up by other inventors. A self-taught German physicist and schoolteacher, Philipp Reis, demonstrated a form of telephone based on these ideas in 1861. Although it could transmit music and certain other sounds along a wire his ‘telephon’ could not transmit intelligible speech. Moreover Reis suffered from ill health and lack of resources so did not patent or develop his prototype.

In Italy, Innocenzo Manzetti had been working on an automaton since 1849. His attempts to make his robot speak led him to develop a prototype telephone that was demonstrated to the Italian press in 1865. It is said that his humble nature and lack of finance meant he didn't try to commercialise his prototype.

In 1871 an Italian immigrant to the USA, Antonio Meucci, filed a caveat for his ‘teletrofono’ invention based on a communication link he had rigged up between his basement lab and his second-floor bedroom to keep in touch with his ailing wife. (A caveat is a warning to others that he was in the process of inventing a device and has a general description of the invention not yet perfected.) Once again though, like Reis, Meucci suffered from illness and lack of resources. Not only could he not afford to convert his caveat into a full patent application, he couldn't afford the annual renewal fee and allowed his caveat to expire. In 2001 in a resolution acknowledging Meucci's contribution to the invention of the telephone, the US Congress said, ‘if Meucci had been able to pay the $10 fee to maintain the caveat after 1874, no patent could have been issued to Bell’.

Bell was an elocution teacher of deaf pupils who was working on a device to translate sound into visible patterns that would allow deaf people to ‘see’ speech. While working on this device he realised the potential for improving the telegraph if a wave of undulating current could be transmitted along the wires instead of the existing intermittent pulses. This would allow a larger number of signals to be transmitted on the same telegraph circuit – each signal using a different musical note. This would make the system more efficient and reduce the need to erect many more new lines to cope with the growth in traffic.

Bell was among a number of inventors racing to be the first to produce a working prototype of what became known as the musical or harmonic telegraph. On 3 June 1875, while working on a prototype of the harmonic telegraph, Bell heard the sound of his assistant Watson plucking a metal reed on the sending device. After further experimentation Bell filed an application for a patent – said to be the single most valuable patent in history – on 14 February 1876 for an ‘improvement to telegraphy’ in which the transmission of ‘noises or sounds’ was merely one of the ‘other uses to which these instruments may be put’. There was no mention of speech. Amazingly, however, only a few hours later another inventor, Elisha Gray, filed a caveat at the US Patent Office for a similar device. In other words, to say the telephone was invented in 1876 doesn't tell the whole story – invention is an ongoing process not a one-off event.