Joost Bürgi

Joost Bürgi, or Jobst Bürgi (February 28 1552, Lichtensteig, Switzerland - January 31 1632),active primarily at the courts in Kassel, Hesse-Kassel (or Hesse-Cassel)) and Praha was a Swiss clockmaker, a maker of astronomical instruments and a mathematician.

Joost Bürgi is widely considered one of the most innovative and most skillful 'mechanics' of his era. It has been suggested that he should also be counted among the leading astronomers of his time because his unprescedented ability to design and construct mechanical models of the movement of heavely bodies proves an advanced level of insight into celestial mechanics. His classification as a scholar is controversial because he lacked a formal education and did not know Latin, the only language of scholarly publications at the time, and because he left few written records of his work. However other historians of science claim that Bürgis legacy of many unique and innovative mechanical astronomical models should be considered an unorthodox method of 'publishing' astronomical insights . [ "Jost Bürgi"; by Ludwig Oechslin; Publisher: Verlag Ineichen, Luzern, 2001, 108 p. ] . During his years in Praha he worked closely with the astronomer Tycho Brahe at the court of Rudolf II.

Bürgi as a clockmaker

It is undocumented where he learned his clockmaking skills, but eventually he became the most innovative clock and scientific instrument maker of his time. ["Jost Bürgi als Künstler der Mechanik, Separatum Toggenburgerblätter für Heimatkunde 1982/Heft 34"; by Johann Wenzel; Publisher: Toggenburgerblaetter ] [ "Jost Burgi 1552-1632, Horloger, Astronome & Mathematicien"; by M.L. Defossez; Publisher: SSC, separate offprint of a 20 page biographic article on Jost Burgi, first published in the 1943 Annual Bulletin of the Societe Suisse de Chronometrie ] Among his major horological inventions were the cross-beat escapement, and the remontoire, two mechanisms which improved the accuracy of mechanical clocks of the time by orders of magnitude. This allowed for the first time clocks to be used as scientific instruments, with enough accuracy to time the passing of stars (and other heavenly bodies) in the crosshairs of telescopes to start accurately charting stellar positions.

Working as an instrument maker for the court of the Margraf Wilhelm in Kassel [ "Die erste Sternwarte Europas,mit Ihren Uhren und Instrumenten, 400 Jahre Jost Buergi in Kassel", by Ludolf von Mackensen, Hans von Bertele & John H. Leopold; Publisher: Callwey Verlag; ISBN: 3 7667 0875 9] he played a pivotal role in developing the first astronomical charts. He invented logarithms as a working tool for himself for his astronomical calculations, but as a "craftsman/scholar" rather than a "book scholar" he failed to publish his invention for a long time. [ "Jost Bürgi"; by Ludwig Oechslin; Publisher: Verlag Ineichen, Luzern, 2001, 108 p. ]

Later Bürgi was based at the imperial court of Rudolf II, Holy Roman Emperor in Prag where he also worked with the astronomer and cosmologist Johannes Kepler.

The most significant artifacts designed and built by Burgi surviving in museums are:

*Several mechanized celestial globes (now in Paris, Zuerich (Schweizerisches Landesmuseum), Stuttgart)

*Several clocks in Kassel, Dresden (Mathematisch Physikalischer Salon) and Vienna (Kunsthistorisches Museum)

*Sextants made for Keppler (at the National Technical Museum in Prag)

*The Mond-Anomalien-Uhr (a mechanical model of the irregularities of the motion of the Moon around the Earth)

Bürgi as a mathematician

He invented logarithms independently of John Napier, since his method is distinct from Napier's. Napier published his discovery in 1614, and this publication was widely disseminated in Europe by the time Bürgi published at the behest of Johannes Kepler. There is evidence [Florian Cajori, "Algebra in Napier's Day and Alleged Prior Inventions of Logarithms," p. 93 of "Napier Tercentenary that Bürgi arrived at his invention as early as 1588, six years before Napier began work on the same idea. By delaying the publication of his work to 1620, Bürgi lost his claim for priority in historic discovery. ["e:The story of a Number", by Eli Maor. page 14. Princeton University Press (Princeton, New Jersey) (1994) ISBN 0-691-05854-7 ] Bürgi was also a major contributor to "prosthaphaeresis", a technique for computing products quickly using trigonometric identities, which predated logarithms.

The lunar crater Byrgius is named in his honor.

References

http://www-history.mcs.st-andrews.ac.uk/Mathematicians/Burgi.html