Charles Wheatstone (6.02.1802-19.10.1875)-an English physicist, Fellow of the Royal Society. Born in Gloucester. From 1834 he was professor at King's College in London.
His work was in electromagnetism, acoustics and optics. In 1837 he constructed the electromagnetic telegraph, and in 1858 the first practicable automatic telegraph apparatus, in which the text of a telegram was recorded in Morse code on a perforated tape. In 1843 he invented a method of measuring resistance (the Wheatstone bridge). He constructed the first variable rheostats (three types). In 1834 he made the first measurements of the speed of the flow of current in conductors by the method of a rapidly rotating mirror (he tried to use this method to measure the speed of light). He built (1838) the stereoscope (with mirrors). Independently of others, in 1867 he proposed the principle of the self-excitation of electrical machines. In 1835, studying the spectrum of an electric spark, he concluded that it depends only on the material of the electrodes and not on the gas in which the spark passes.
He also made musical instruments, invented the concertina in 1829, explained in 1833 the acoustic figures of Chladni, and established (1837) that the timbre of a sound is determined by the relative intensity of the overtones.