Parabolic trajectum by breton a paris c 1820

Parabolic trajectum by breton a paris c 1820. This object is currently displayed at museum boerhaave aan de vecht. When a body falls, its vertical velocity increases uniformely. If the body also has a horizontal velocity, than the resolting trajectory will be in the shape of a parabola. A bal would be launched with a horizontal velocity by letting it roll down the curved track. On the board where the 4 rings fixed at differents points, the trajectory and the ball would pass through them. Measurements: 76 x 32 and 46 cm high.