The instrument consists of a glass tube closed at each end by a brass cap with a hook attached. Small pointed strips of metal foil are glued to the tube’s surface, arranged to form a spiral.

If the tube is placed between the conductors of an electrostatic machine, the ends of the strips are charged in opposite directions by induction, generating an intense electric field between their tips. A series of sparks then fly between the strips, creating a spectacular lighting effect.

Device on display.