Quote Originally Posted by Rodin View Post
They're at an observatory, which makes those Focault Pendulums.

It's a pendulum that swings back and forth in a big enough arc to show the rotation of the Earth. Over time the pendulum will touch every point on the outside of the circle as the Earth's rotation causes it to spin. Very cool device.

In the Girl Genius verse the ball has naturally been replaced by a guillotine.
this beeing Girl Genius, it should surprise noone if they actually where stationary.