The oscillating device, which probably belonged to another instrument, consists of a curved bar with a brass disc at either end that is free to swing on a glass support, mounted on a triangular wooden base. Attached to it is a thin rod with two very light gilt discs at the ends.

When one of the brass discs comes into contact with a battery terminal, it acquires a charge of the same sign and is repelled; this movement forces the other disc to touch the other terminal, from which it is repulsed in turn.

Device on display.