Regnier Gemma FrisiusDied 25 May 1555 at age 46 (born 9 Dec 1508).Dutch geographer who was born Regnier Gemma, but following the convention of his times, added a Latin name when he became a scholar. He chose Frisius after his native Friesland province. He worked in the fields of cosmology, astronomy and mathematics. His first publication (1529) was a corrected version of Apianus' Cosmographia (1524). Gemma Frisius also applied his knowledge to catography, construction of globes, and making astronomical instruments. He introduced the principle of triangulation of observed places to accurately locate them on a map (1533). With similar trigonometric methods, he identified that comets exhibited a “proper motion” against the fixed star background. He was also the first to explain how measurement of longitude could be made from elapsed time measurements with a portable timepiece.« |
