Gravesande's whirling globe

Gravesande's whirling globe, to demonstrate frictional electricity, on black wooden stand

This globe was designed by Gravesande to demonstrate frictional electricity.

It is closed at each end by a metal collar and seal and furnished with an axis fitted horizontally in the wooden frame. The globe contains a circular piece of wood at its centre which small threads are attached reaching to the inner surface of the globe. This globe and its stand are mounted on a table in which, by rotation of a large wheel connected to the small wheel on the axis of the globe, the latter can be readily rotated. When rotated and rubbed, the globe is charged with frictional electricity. The globe is then brought to rest and the hand removed when it is seen that the threads stretch out radially from the centre and are undergoing continued agitation under the action of the external air. This motion may be intensified if you blow against the globe. If a finger is applied near the globe, but not touching it, some threads are repelled and others attracted.