Astronomer. He was the sixth English Astronomer Royal, a position he held from 1811 to 1835. The son of a wealthy London Merchant, he attended Trinity College, Cambridge, in 1784 but did not graduate on account of his health. In 1794, he was admitted to Inner Temple in London, a professional association for barristers and judges, but again had to withdraw for health reasons. He settled at Westbury near Bristol, and commenced to calculating star positions, using a fine altitude and azimuth circle two and one-half feet in diameter that was designed by Edward Troughton. In 1806, he demonstrated a change of form in the Greenwich mural quadrant which led to the introduction of astronomical circles at the Royal Greenwich Observatory and to his appointment as its head. In 1807, he moved to London and was elected as a Fellow of the Royal Society, and succeeded Nevil Maskelyne as Astronomer Royal in 1811. During his administration, he employed the method of observation by reflection and devised a means of combining two mural circles to determine the place of a single object, one serving for direct vision and the other for reflected vision. Under his direction, the Royal Greenwich Observatory's instrumental equipment was completely changed and the number of assistants increased from one to six. From 1829 to 1831, he served as the Superintendent of the Nautical Almanac. In 1833, he installed a time ball on the roof of the Observatory which was the first public time signal in England, which was intended to aid mariners on the Thames River to set their marine chronometers. His 1833 catalog of positions of 1,112 stars displayed an accuracy never achieved before. Among his awards and honors were the Lalande Prize in 1817 by the French Academy of Sciences and the Copley Medal in 1823. He was responsible for publishing eight folio volumes of Greenwich Observations, translated Pierre-Simon Laplace's "Systeme du Monde" and contributed 31 papers to scientific collections. He retired from the Astronomer Royal position in 1835 due to poor health.