A nonmetallic element, of the halogen group of atomic number 53, occurring always in combination, as in the iodides. When isolated it is in the form of dark gray metallic scales, resembling plumbago, soft but brittle, and emitting a chlorinelike odor. Symbol I. Atomic weight 126.90. If heated, iodine volatilizes in beautiful violet vapors. [1913 Webster
" Iodine was formerly obtained from the ashes of seaweed (kelp or varec), but is now also extracted from certain natural brines. In the free state, iodine, even in very minute quantities, colors starch blue. Iodine and its compounds are largely used in medicine (as in liniments, antisyphilitics, etc.), in photography, in the preparation of aniline dyes, and as an indicator in titration."