The globe itself rotates within a metallic meridian to which its axis is attached.

Hence when a current is passed through the meter, the armature rotates and increases its speed until the driving force is balanced against the retarding force due to the eddy currents in the copper brake disk.

when one piece rotates, and the other shifts, the axis of the rotMing piece, and all the points of contact, lie in a plane perpendicular to the direction of motion of the shifting piece.

In reality the head and foot are fixed and the shell rotates from right to left.

This cone is driven by gearing from the wire drum, so that it rotates at the speed of the outgoing wire, the direction of rotation being such as to cause the nut to travel towards the smaller end of the cone.