Frictional electrical machine, similar to the small portable cylinder generators made by Edward Nairne, also referred to as the "English pattern" machine. The glass cylinder is rotated by a two-pulley system; the leather cushion is supported on a glass pillar and secured to wooden strips sliding in the cross-piece of the frame. This arrangement allows the operator to adjust the pressure of the cushion—and consequently the amount of friction—on the glass. A machine of this type was used by Nairne for experiments on lightning conductors c. 1778. Provenance: Lorraine collections.