Xenon was the last noble gas to be discovered. In the sequence of several studies made by William Ramsay and M. W. Travers, in 1898, and as a result of the krypton purification by fractional distillation, it was obtained an extremely dense gas that those two scientists were unable to identify. The spectroscopic analysis of that gas revealed that was a new element that was named xenon. This name derives from the Greek word xenon that means "strange".