Major part of 452 stereoscopic pairs of cloud chamber photographs and five single photographs of electric discharges (all glass negatives), stored in 28 cardboard packs and 21 paper packs, by Charles Thomson Rees Wilson, Cambridge, England, 1922 and glass plates by the Imperial Dry Plates Co. Ltd, Cricklewood, London, England, 1918-1922 Major part of 452 stereoscopic pairs of cloud chamber photographs and five single photographs of electric discharges 1922; 1918-1922