The globe itself rotates within a metallic meridian to which its axis is attached.
In other types of electrostatic instruments the movable system rotates round a horizontal axis or rests upon knife edges like a scale beam; in others again the movable system is suspended by a wire.
Here BB is a large fixed iron cylinder, corrugated within, and C an excentric cylinder, also corrugated, which, in turning to the right, by the friction of its corrugated surface rotates the puddled ball D which has just entered at A, so that, turning around its own axis, it travels to the right and is gradually changed from a ball into a bloom, a rough cylindrical mass of white hot iron, still dripping with cinder.
22, rotates about its own axis, rolling on the rollers M shown in fig.
Altitude is fixed, and rotates with it; both can be clamped to the standard, and motion can be given by a suitable double-ended motion screw.