When was krypton discovered?

Krypton was discovered in 1898 by William Ramsay and Morris Travers, along with neon and xenon in a series of air-separation experiments. Its name comes from the Greek kryptos, meaning “hidden,” because it was difficult to detect in air. Krypton is a noble gas and occurs only in tiny amounts in the atmosphere. One of its isotopes is used in science as a reference for the meter, but the element itself is best known for being extremely rare.