A crystal bell (aperture 34 cm, height 30 cm) suspended with a brass ring from a wooden support consisting of a arch held by two well-lathed columns on a rectangular base (51 x 24 cm). Its overall height is 57 cm. A hammer with an adjusting screw at the end of a thin steel plate fixed to the supporting arch almost reaches the bottom of the bell.
With excellent aesthetic qualities, it was used to demonstrate that sound is produced by vibrating bodies. In fact, if a violin bow is used to make the bell vibrate, and by means of the adjusting screw the hammer is brought closer, it is possible to hear the characteristic noise generated by the hammer striking the wall of the bell. Since the former is fixed to the support, this proves that the walls of the bell vibrate.
