A large brass conductor consisting of a central, cylindrical part (diameter 6 cm, length 35.5 cm) and two large balls (diameter 10.5 cm) on the ends of the cylinder. The cylinder is held by a sturdy glass insulating shaft fixed to a wide circular brass base. Under the two spheres are two hooks to which can be attached two reeds of metal or two elder pith balls by means of a thin conducting wire.
Its overall height is 43 cm. It was used to study how the charge of an insulated conductor is distributed, or how the induced charge is distributed by placing it so that one of the ends is very close to a charged body or to one of the poles of an electrostatic generator.