Named for Jost Bürgi (1552–1632) of Lichtensteig in the Toggenburg valley, who won European fame as a highly skilled maker of precious instruments for astronomy and geometry. As a practical mathematician, he also devised and used refined new methods. Initially in the service of the landgraves Wilhelm and Moritz of Kassel, he later served the emperors Rudolf and Mathias in Prague, where he became a good friend and helper to Kepler {see planet  (1134)}. Bürgi on his own invented logarithms, but being slow (or even loath) to publish his system, he lost the priority to John Napier. (M 21129) _ _.