The Machine of Bohnenberger: Bicentennial of the Gyro with Cardanic Suspension

Abstract

AbstractIn 2004, a gyro with cardanic suspension was recovered in the physical collection of a school in Tübingen, Germany. Up to now, this instrument seems to be the only original corresponding explicitly with the first systematic explanation of such an apparatus. This description dates back to 1817 and was written by the inventor J.G.F. Bohnenberger (1765‐1831), who called the device simply Machine. At that time, Bohnenberger was professor for mathematics, physics, and astronomy at the University of Tübingen as well as the scientific head of the historic Württemberg land surveying. The discovery made aware that the historical background of the Machine of Bohnenberger was mainly unexplained. This is remarkable as the instrument was the basis for Foucault's famous work on gyros and as it paved the way to important mechanical navigation instruments like the directional gyro, the artificial horizon, and finally inertial platforms. Therefore, the finding in Tübingen prompted the authors to search for additional historical documents sheding light on Bohnenberger's invention. Meanwhile, several original specimen manufactured by Bohnenberger's instrument maker J.W.G. Buzengeiger (1778‐1836) could be identified, and it was possible to narrow the invention down to the year 1810. The paper outlines the historical background of the Machine of Bohnenberger currently known and sketches the biography of its inventor. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)