An old engraving of Gray’s ‘electro-harmonic telegraph’ of 1874. It is from a Victorian book of the 1880s. Elisha Gray (1835 –1901) was an American electrical engineer who co-founded the Western Electric Manufacturing Co. Gray is best known for his telephone prototype in 1876. His harmonic telegraph consisted of multi-tone transmitters, each tone with a telegraph key, transmitting musical tones. Oscillations were created by electromagnets and via a telegraph wire to a receiver (bott right) which reproduced the sound via a hollow metal cylinder on top of two magnets.
An old engraving of Gray’s ‘electro-harmonic telegraph’ of 1874. It is from a Victorian mechanical engineering book of the 1880s. Elisha Gray (1835 –1901) was an American electrical engineer who co-founded the Western Electric Manufacturing Company. Gray is best known for his development of a telephone prototype in 1876 in Highland Park, Illinois, USA. In 1874 he applied for a patent on a harmonic telegraph which consisted of multi-tone transmitters, that controlled each tone with a separate telegraph key. Gray gave several private demonstrations of this invention that year. It transmitted musical tones (‘familiar melodies through telegraph wire’). This was one of the earliest electric musical instruments using vibrating electromagnetic circuits that were single-note oscillators operated by a two-octave piano keyboard. It used steel reeds whose oscillations were created by electromagnets and transmitted over a telegraph wire – here to (bottom right) a receiver which reproduces the sound via a hollow cylinder of metal on top of the poles of two magnets.
Size: 3780px × 3489px
Location: Highland Park, Illinois, USA
Photo credit: © M&N / Alamy / Afripics
License: Licensed
Model Released: No
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