Thomas Young (June 13, 1773 - May 10, 1829) was an English polymath. He made notable scientific contributions to the fields of vision, light, solid mechanics, energy, physiology, language, musical harmony, and Egyptology. He began to study medicine in London in 1792. In 1793 he explained the mode in which the eye accommodates itself to vision at different distances as depending on change of the curvature of the crystalline lens. He moved to Edinburgh in 1794, and a year later went to Germany where he obtained the degree of doctor of physics in 1796. In 1801 he was appointed professor of natural philosophy at the Royal Institution. In two years he delivered 91 lectures. He was the first to describe astigmatism, and in his lectures he presented the hypothesis, afterwards developed by von Helmholtz, that color perception depends on the presence in the retina of three kinds of nerve fibrers. He resigned his professorship in 1803, fearing that its duties would interfere with his medical practice. He put forth a number of theoretical reasons supporting the wave theory of light, and he developed two enduring demonstrations to support this viewpoint. With the ripple tank he demonstrated the idea of interference in the context of water waves. With the Young's interference experiment, or double-slit experiment, he demonstrated interference in the context of light as a wave. He was one of the first to try and decipher Egyptian hieroglyphs. By 1814 he completely translated the enchorial text of the Rosetta Stone. In physiology he made an important contribution to hemodynamics and derived a formula for the wave speed of the pulse. He also developed the Young temperament, a method of tuning musical instruments. He died in 1829 at the age of 55.