• Thus the radio elements formed strange and cruel families in which each member was created by spontaneous transformation of the mother substance: radium was a "descendant" of uranium, polonium a descendant of radium.

    Eve Curie: Thus the radio elements formed strange and cruel families in which each member was created by spontaneous transformation of the mother substance: radium was a "descendant" of uranium, polonium a descendant of radium.
    Ève Curie (1937). “Madame Curie: a biography”