Eugène-Anatole Demarçay (1 January 1852 – 5 March 1903) was a French chemist who designed an apparatus to produce a spark using an induction coil and used it to generate the spectra of rare earth elements which he examined using spectroscopy, thus detecting the element europium in 1896, and isolated it as the oxide europia in 1901. He helped Marie Curie to confirm the existence of another new element, radium, in 1898.