Léon Foucault Catholicism that he previously abandoned. Foucault died of what was probably a rapidly developing case of multiple sclerosis on 11 February 1868 in Paris and was buried in the Montmartre Cemetery. The asteroid 5668 Foucault was named for him. His is one of the 72 names inscribed on the Eiffel Tower. Collected Works: Léon Foucault Jean Bernard Léon Foucault (; 18 September 1819 – 11 February 1868) was a French physicist best known for his demonstration of the Foucault pendulum, a device demonstrating the effect of the Earth's rotation. He also made an early measurement of the speed of light,
Foucault pendulum latitude, viewed from above by an earthbound observer, rotates counterclockwise 360° in two days. To demonstrate rotation directly rather than indirectly via the swinging pendulum, Foucault used a gyroscope in an 1852 experiment. The inner gimbal of the Foucault gyroscope was balanced on knife edge bearings on the outer gimbal and the outer gimbal was suspended by a fine, torsion-free thread in such a manner that the lower pivot point carried almost no weight. The gyro was spun to 9000–12000 revolutions per minute with an arrangement of gears before being placed into position, which was sufficient time to balance the