Invention of the telephone

The telephone was not the work of a single inventor but the outcome of decades of experiments in Europe and North America, ending in a race to the patent office in 1876. Alexander Graham Bell received the decisive American patent that year and built the first successful telephone business, but Antonio Meucci, Philipp Reis, Elisha Gray and others made important contributions, and their rival claims fuelled lawsuits and arguments that continue today.

The basic idea of carrying the voice along a taut string between two diaphragms had long been known. The electric telegraph, including the electromagnetic device built by Carl Friedrich Gauss and Wilhelm Weber at Göttingen in 1833, supplied the other half of the puzzle. In 1854 the French telegraph engineer Charles Bourseul described, though he did not build, a telephone in which a vibrating disc would make and break an electric current. In Germany, Philipp Reis developed a telephone from 1857 and presented it to the Physical Society of Frankfurt in October 1861. It could carry musical tones and some speech, and caused excitement abroad, but it was not a practical instrument.

The Italian inventor Antonio Meucci, working in Havana and later on Staten Island, New York, experimented with voice transmission from around 1849, and is said to have rigged a device in his home to talk to his invalid wife in the 1850s. In 1871 he filed a patent caveat, a notice of intent to patent, but it did not describe the key features of an electromagnetic telephone, and in poverty he let it lapse after 1874. Much of the detailed evidence for his priority was reconstructed only in the 1880s, and in the patent case of Bell v. Globe and Meucci the court ruled against him. In 2002 a symbolic resolution honouring his work passed the United States House of Representatives, and Canada's parliament responded by recognising Bell.

Bell, a teacher of the deaf and professor of vocal physiology at Boston University, began experimenting with a harmonic telegraph in 1873–1874, as did Elisha Gray in Illinois. On 2 June 1875, when his assistant Thomas Watson plucked a stuck reed, Bell realised that a continuous, varying current could carry the full complexity of the voice. On 14 February 1876 Bell's lawyer filed his patent application on the same day that Gray's lawyer lodged a caveat for a telephone using a liquid transmitter. Bell's fee was recorded first, Gray later dropped his claim, and Bell received US patent 174,465 on 7 March 1876. Whether Bell's application borrowed from Gray's remains disputed.

On 10 March 1876 Bell spoke the first clear sentence to Watson in another room, asking him to come to him. That summer he showed the telephone at the Centennial Exhibition in Philadelphia, where it impressed the Brazilian emperor Pedro II. In August 1876, at his parents' home near Brantford, Ontario, in Canada, he made a series of test calls over telegraph lines, including a one-way call to Paris, Ontario, often described as the first long-distance call. The first two-way conversation over a line, between Boston and Cambridge, followed on 9 October 1876. In January 1878 Bell demonstrated the device to Queen Victoria at Osborne House, placing calls as far as London.

The Bell Telephone Company was founded in 1877 and quickly made Bell wealthy. The early instruments were faint, but around 1878 the carbon microphone was developed by David Edward Hughes in England and by Emile Berliner and Thomas Edison in the United States. It gave a much stronger signal and made long-distance calls practical; it remained standard until the 1980s. The Hungarian engineer Tivadar Puskás, working for Edison, proposed the telephone exchange, which let any subscriber reach any other, and within a year of Bell's patent the first exchange had been built in Connecticut. It has been argued that Bell's greatest achievement was not the instrument itself but the creation of the telephone industry.

Our 1878 and 1880 maps show the United States and Canada, where the decisive work took place, in the years when the telephone spread from Boston across the industrial world.