Charles Wheatstone (1802-1875), British physicist. Wheatstone study of acoustics and the theory of resonance of columns of air, lead to his 1829 invention of the concertina musical instrument. He invented the printing telegraph (1841) and the single-needle telegraph (1845). He popularised the Wheatstone bridge, invented by Samuel Christie, which measures resistance in electrical circuits. Wheatstone also invented the stereoscope (1838) for making three-dimensional photographic images. Artwork from 'Electricite' (1911) by Max de Nansouty, part of the 'Les merveilles de la science' series of 1867-1891 by Louis Figuier.