Paris - Panthéon View - 5me

Plate XLV - From The Pantheon, Les Toits de Paris…

Displayed inside the walls of the Panthéon I saw an iron sphere. Weighing some 28 kilograms it had been used by physicist Jean-Bernard-Léon Foucault in an 1851 experiment to demonstrate the rotation of the earth.

Suspended on wire from the 67 metre high roof of the central dome of the Panthéon, the experiment started with the sphere, now known as the Foucalt Pendulum, being set in motion swinging in a vertical plane.

Viewed from above it was observed that the plane of the pendulum rotated clockwise at slightly more than 11° each hour due to the earth’s rotation on it’s axis. This was the first recorded ‘laboratory’ proof of this phenomenon.

In quieter moments while his experiment was in progress I imagine this is the view that Foucault and his observers would have contemplated, while looking over the roofs of Paris. Many well known landmarks can today be seen – but it’s strange to think there was no Eiffel Tower there in Foucault’s time.

The view does inspire thinking.