Xenon, ZEE non or ZEHN on, is a chemical element that makes up about 1 part in 20 million of Earth's atmosphere. The British chemists Sir William Ramsay and Morris W. Travers discovered xenon in 1898 (see Ramsay, Sir William). Industry uses xenon in filling flash lamps and other powerful lamps. Xenon is also used to make bubble chambers, which are instruments used by physicists to study nuclear particles.