EUROPIUM is a very rare metallic element (symbol Eu, atomic number 63, atomic weight 152.o) belonging to the rare earth group, discovered in 1896 by Demarcay. Previously, in 1889, Crookes noticed a band in the spectrum of some earths from samarskite and to the substance giving this spectrum he provision ally gave the name S . This was found, later, to be identical with europium. It was first obtained in a pure state by G. Urbain and H. Lacomb in 1904 by the employment of a very ingenious method which involved the crystallization of the double magnesium nitrates of the rare earths along with the isomorphous bismuth magnesium nitrate. The latter possessed a solubility similar to that of the europium salt and thus, by increasing the bulk of material, made the process easier to carry out. Owing to the great rarity of this metal, it is best obtained from the crude mixture of samarium and gadolinium oxides derived from monazite. The salts possess a pale pink colour and show a faint absorption spec trum. The spark spectrum of this element is very brilliant. (See RARE EARTHS.) (C. J.) EURYDICE, in Greek mythology, the wife of Orpheus (q.v.).