A rare Voss type electro-static friction generator, with bone makers plaque, signed DRING & FAGE Opticians And Scientific Instrument Makers 145 STRAND LONDON, with further plaque W.H.PYWELL, with contra-rotating plates, conductor combs, attached to conductor cylinders, with leather driving bands to side mounted flywheel and turning handle, on mahogany plinth base c.1880 (damaged) - 20½in.(52cm) wide