CERIUM, Ce, = 141.

This metal, which is not a common one, was discovered by Berzelius, in a Swedish ore called cerite or heavy-stone - a silicate of iron, calcium, lanthanium, didymium, and cerium, which last is obtained from it in the form of a gray metallic powder: oxalic acid is used in the process, and hence oxalate of cerium is the best known commercial salt: it is the only one officinal.