If you guessed that this was used to keep track of time, then you’re correct! This device, known as a Congreve Clock (or a rolling ball clock) , was created by Sir William Congreve in 1808 as an alternative to the pendulum style clocks that were popular at the time. The clock features a rolling ball that zig zags down a path, laid out on a plate. When the ball reaches one end of the plate, it activates a lever and raises the other end of the plate, sending the ball back on the path. And while the craftsmanship and mechanics are amazing, it wasn’t the most reliable at keeping time. See one in action in the following clip from M.S.Rau Antiques.