Its properties were first studied into by M.Gay Lussac.

It partakes much of the nature of chlorine and bromine.

Its affinity for other substances is so powerful as to prevent it from existing in an isolated state.

It occurs combined with potassium and sodium in many mineral waters, such as the brine spring of Ashby-de-la-Zouche, and other strongly saline springs.

This combination exists sparingly in sea-water, abundantly in many species of fucus or sea-weed, and in the kelp made from them.