KRYPTON, a gaseous element discovered in the atmosphere by Ramsay and Travers, in 1898. (The history of this member of the argon group is so bound up with that of argon itself that reference should be made to the article ARGON, and to the references there given). Krypton was discovered in the last fraction re maining after the evaporation of a considerable quantity of liquid air. The residue consisted chiefly of argon, oxygen and nitrogen; but when the and nitrogen had been removed, a spectroscopic examination of what remained showed lines that indicated the existence of at least one new element, in addition to argon and helium. To this new element the name "kryp ton* was assigned, from a Greek word signify ing "hidden,* in allusion to the circumstances under which the discovery was made. (See also NEON and XENON). Little is known, as yet, concerning the properties of krypton. When it was isolated by means of a tedious diffusion process, it was found by Ramsay and Travers to have a density about 40.75 times as great as
that of hydrogen and an atomic weight of about 81.5. The ratio of its specific heat at constant pressure to its specific heat at constant volume was found to be 1.66, as in the cases of argon and helium. Subsequent experiments by Laden burg and Kriigel have indicated a density of about 29.5, and therefore an atomic weight of about 59. Travers, in his book issued subse quently to these later experiments, makes no reference to them. Considerations based upon the periodic law (q.v.) appear to indicate that the results of Ramsay and Travers are the more probable; but this point is as yet undecided. Krypton exists in the air in the proportion of about one part in a million. It has the chemical symbol Kr and appears to be as inert, chemi cally, as argon.