CELTIUM is the name given by G. Urbain and A. Dauvillier to the element of atomic number 72, for which the former ob tained some evidence from X-ray spectra in 1911. Their claim to have discovered this element was, however, disputed by D. Coster and G. Hevesy (19 23) who named it Hafnium, under which head ing it is described. Of the resulting polemical papers only a few are suggested for reference.
BIBLIOGRAPHY.-D. Coster and G. Hevesy, Nature, III, pp. 79, 252, Bibliography.-D. Coster and G. Hevesy, Nature, III, pp. 79, 252, 462 (1923). G. Urbain and/or A. Dauvillier, ibid., p. 218, Comptes rendus, 176, p. 676 (1923) ; Chemistry and Industry, 42, p. 764 (1923).