Discovery of radium Evaporate to dryness, FC Supernatant I Supernatant Crystals FC More active p of B is combined with less active part of A SupernatantCrystals Supernatant FC Supernatant rystals Supernatant Crystals FC continued for 6 stages: -Activity of the most soluble fraction decreases each time, when it becomes negligible, it is discarded; -At some stage the most active crystals are withdrawn from further FC and pooled: Final yield was nearly 100 mg of pure radium chloride; -Activity nearly 2 x 10 times that of equal weight of uranium 2005-9-13 NECPKU