Foucault pendulum sharing the rotation of the earth about its own axis, the suspension point of the pendulum traces out a circular path during one sidereal day. At the latitude of Paris, 48 degrees 51 minutes north, a full precession cycle takes just under 32 hours, so after one sidereal day, when the Earth is back in the same orientation as one sidereal day before, the oscillation plane has turned by just over 270 degrees. If the plane of swing was north-south at the outset, it is east-west one sidereal day later. This also implies that there has been exchange of momentum;
Pierre-François-Victor Foucault Société d'encouragement pour l'industrie nationale, then he showed it at The Great Exhibition (1851) in London. Pierre-François-Victor Foucault Pierre-François-Victor Foucault (1797-1871) was the inventor in 1843 of the first printing machine for braille, the . A pupil of the Institut National des Jeunes Aveugles, Foucault married Thérèse-Adèle Husson, a blind author, in 1826. This marriage gave birth to two daughters. After his wife's death in 1831, following a fire, he married a seamstress (non blind) in 1832, Adélaïde Louise Juteau. This allowed him to become a resident of the Quinze-Vingts (marriages between blind people were prohibited), which gave him the