Charles Wheatstone
Sir Charles Wheatstone [ wi ː tstən ] ( born February 6, 1802 in Gloucester, † October 19th 1875 in Paris) was a British physicist.
Life and work
After visiting several schools, Wheatstone worked in the craft of his uncle, the instrument, and took over the business after his death in London in 1823 with his brother William. Charles had no great interest in commercial and artisanal activities, and so he focused more on improving the instruments and the development of technical aids. In 1829, he withdrew completely back out of business. In 1834 he became professor of experimental physics at King's College in London.
Wheatstone began early with physical- acoustic experiments in which he examined the transmission of sound, standing waves and musical instruments. In 1828 he invented the Symphonion, a precursor instrument of the accordion-like concertina. He designed in 1833 in a treatise of the Royal Society presented the principle of superposition of small movements for the Chladni figures. Then he turned to the optics and electronics, and recognized in 1833 the importance of invented by Samuel Hunter Christie bridge circuit for the precise measurement of electrical resistors, which later became known as the Wheatstone bridge.
In 1840 he invented a continuously variable resistor ( rheostat ), and in 1833 the mirror stereoscope, with which he determined the spectral lines of spark discharges. 1834 determined Wheatstone first propagation speed of the electric current in the metallic conductors. In the following he developed together with the electrical engineer William Fothergill Cooke two telegraphic - the needle telegraph, and the pointer telegraph. The latter found widespread use and was later supplanted by the Morse code. The transmitting and receiving device of the pointer telegraph consisted of the movement of a pointer to individual letters and digits, which elicited a different numbers of pulses. 1854 Wheatstone invented the Playfair method for manually encrypt messages.
Almost simultaneously with Werner von Siemens discovered and published Wheatstone also the dynamo-electric principle. Wheatstone 's lecture to the Royal Academy on February 14, 1867 was immediately followed by the contribution of William Siemens ' who had presented the work of his brother Werner von Siemens. The presentations to the Royal Society was preceded by the publication of the first scientific presentation of the dynamo- electric principle before the Berlin Academy of Sciences on 17 January 1867. Wheatstone dealt with the parallel circuit of the armature and field winding as opposed to Siemens 's variant with a series circuit. The version of Wheatstone later turned out especially for power plant engineering as a major.
Wheatstone and his friend Baron Lyon Playfair operated by St. Andrews, the Cryptography as a hobby. At the time, appeared in the London Times, often personal advertisements in encrypted form. The two made fun of it, to decode these secret messages. Especially the ads of lovers had it done to them. Wheatstone manually developed encryption method, based on the pairs of letters. Playfair published later and so this method got its name.
Honors
In 1836 he was elected a member ( "Fellow" ) of the Royal Society, who twice (1840 and 1843) with the Royal Medal in 1868 and awarded him the Copley Medal. He was also since 1868 of the Order Pour le Mérite for Sciences and Arts. After awards in various countries followed in 1868 his elevation to the peerage.