Designed by Charles Edouard Joseph Delzenne in the 1840s, this demonstration device from around the turn of the 20th century can be used to indicate the presence and orientation of the Earth’s magnetic field. By spinning the round coil of wire, a voltage is produced at the copper brushes attached to the square frame. The voltage reaches a maximum when the square frame is in a plane perpendicular to the Earth’s magnetic field.
Made in Chicago
Made of wood, brass, and wire