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 vector diagrams or aligned to the Earth's axis and the sine of 90° = 1. At the equator the pendulum axis is perpendicular to the Earth's axis and the sine of 0° = 0. At intermediate latitudes the rotation of the Earth is observable in relation to the plane of the pendulum swing but the time to observe a full rotation depends on the latitude of the location. The time to observe a full rotation is equal to one day at the North Pole with the time increasing with decreasing latitude and not observable at the Equator (infinite length of time). The