A large aluminium and Perspex Van de Graaff electrostatic generator W.B. Nicholson Scotland, mid 20th century Constructed with two-part aluminium sphere 12 inches in diameter enclosing fabric covered Perspex pulley over cylindrical plexiglass column above stepped domed base enclosing electric motor driving a conforming pulley, the exterior with FAST/SLOW adjustment knob and tradeplate inscribed VAN DE GRAAFF, GENERATOR around an diamond lozenge enclosing initials WBN, (rubber belt lacking), 98m (38.5ins) high and with insulated short stool; with an 'Earth Inducer' flip coil, the wooden frame with central circular rotating coil incorporating connection posts and detents to lower pivot and disc calibrated for degrees of rotation to the top, the outer frame pivoted at 90 degrees between two panel uprights over base with trade label inscribed SERIAL No. 20148, 400 TURNS 36G D.S.C. COPPER, MEAN DIAMETER 27.7 CM, PHILIP HARRIS LTD. BIRMINGHAM, 54.5cm (21.5ins) wide, (2). Provenance: By repute the Van de Graaff generator featured in an episode of the Dr. Who spin-off television series 'Torchwood'. The Van de Graaff generator was developed bt the American physicist Robert J. Van de Graaff in 1929 as a particle accelerator for physics research; its high potential was designed to be used to accelerate subatomic particles to great speeds in an evacuated tube. It was the most powerful type of accelerator of the 1930s until the cyclotron was developed. Van de Graaff generators are still used as accelerators to generate energetic particles and X-ray beams for nuclear research and nuclear medicine as well as for educational demonstration purposes.The Van de Graaff works on the principal that the simple contact of dissimilar materials causes the transfer of some electrons from one material to the other. In operation the rubber of the belt will become negatively charged while the acrylic glass of the upper roller will become positively charged. The belt carries away negative charge on its inner surface while the upper roller accumulates positive charge within the aluminium globe. The size of the globe dictates the voltage potential that the instrument can accumulate but typically larger examples (as per the current lot) can generate in the region of 250,000 Volts. The Earth Inductor apparatus was devised by Charles Edouard Joseph Delzenne (1776-1866). The instrument is designed to measure the magnitude and direction of the earth's magnetic field using a flip coil in conjunction with a ballistic galvanometer. This is done by quickly flipped the coil through 180 degrees, and reading the output. By measuring the total charge delivered by the induced EMF the magnitude of the magnetic field threading the coil can be ascertained.