Jost Bürgi

Jost Bürgi was a Swiss clockmaker, mathematician and writer, born at Lichtensteig in the Toggenburg on 28 February 1552 and died on 31 January 1632. He worked mainly at the courts of Kassel and Prague and was the brother-in-law and adoptive father of Benjamin Bramer. An autodidact, he was already in his lifetime counted among the finest mechanical engineers of his generation, and William IV, Landgrave of Hesse-Kassel, called him a second Archimedes in a letter to Tycho Brahe. He was appointed court astronomer at Kassel in 1591 and in 1604 entered the service of Emperor Rudolf II in Prague, where he befriended Johannes Kepler. By 1586 he could calculate sines to arbitrary precision, and he is said to have computed a table of sines, the Canon Sinuum, which Kepler called the most precise known and which is now lost. He built a table of progressions that are now understood as antilogarithms independently of John Napier, around 1600, although it is not a theoretical basis for logarithms. As a clockmaker he introduced the cross-beat escapement and the remontoire, and he built mechanised celestial globes. The lunar crater Byrgius is named for him.