German(?) c.1880, unsigned, on a heavy metal base with a pendulum in a glass tank to damp/slow the movement with water, the escapement mechanism mounted between two glass windows that form the 'slide' with a pully at the top for a weight (missing)

Note: this instrument would have been used in conjunction with a scientific magic lantern. It would have been used to project on to the screen a moving escapement to show students the method of operation