Xenon - 54Xe: historical information
Xenon was discovered by Sir William Ramsay and Morris Travers in 1898 in the residue left after evaporating liquid air components. Krypton and neon had been discovered by the same methods by the same workers only weeks earlier. They had to work with huge volumes of air to produce just a little xenon since it turned out that xenon is only present to the extent of about 0.087 ppm in the atmosphere.