Foucault pendulum 2010, the cable suspending the bob in the Musée des Arts et Métiers snapped, causing irreparable damage to the pendulum and to the marble flooring of the museum. An exact copy of the original pendulum has been operating under the dome of the Panthéon, Paris since 1995. At either the North Pole or South Pole, the plane of oscillation of a pendulum remains fixed relative to the distant masses of the universe while Earth rotates underneath it, taking one sidereal day to complete a rotation. So, relative to Earth, the plane of oscillation of a pendulum at the North Pole
In Which We Serve leads to a flashback in which Blake remembers how he met his wife-to-be, Freda, on a train while on leave. It is also revealed that she is related to the "Torrin"'s affable Chief Petty Officer Hardy (Miles). When both men return to sea, Freda moves in with CPO Hardy's wife and mother-in-law. The "Torrin" participates in the Dunkirk evacuation of the British Expeditionary Force, (portrayed in the film by the 5th Battalion of the Coldstream Guards). Meanwhile, the nightly Blitz takes its toll on British towns. Blake soon gets a letter from home to say that Freda has given birth