Johann Gottlieb Friedrich von Bohnenberger

Johann Gottlieb Friedrich von Bohnenberger was born in 1765 in the Swabian village of Simmozheim, the son of a Lutheran pastor who taught him astronomy and surveying before he had finished school. He studied theology at Tübingen, then mathematics at Göttingen under Lichtenberg and Kästner, and returned to Tübingen in 1796 as professor of mathematics and astronomy — a chair he held until his death thirty-five years later.

His place in the history of physics rests on a single instrument. In 1817, in his Beschreibung einer Maschine zur Erläuterung der Gesetze der Umdrehung der Erde um ihre Axe, he described a brass sphere mounted at the centre of three concentric gimbal rings, free to tilt and precess in any direction without the outer frame disturbing its axis. When spun up, the sphere's rotation axis stayed fixed in space while the frame was turned. It was the first modern gyroscope — thirty-five years before Foucault's independent rediscovery would give the device its name.

Bohnenberger did not publish a dynamical theory of his machine. He demonstrated it in lectures, sold copies to instrument collectors across Europe, and let Poisson and Laplace write the mathematics. When Foucault built his own gimbal gyroscope in 1852 to demonstrate Earth's rotation, he gave the device its modern name but acknowledged Bohnenberger as its inventor. The three-ring gimbal architecture became the canonical form for inertial reference instruments, from the V-2's primitive guidance set to the Apollo Guidance Computer's IMU.