The salt, it appeared, was obtained by simple sublimation from soot.
It is a soft, flocculent powder, which on sublimation forms transparent, monoclinic crystals.
Arsenic possesses a steel-grey colour, and a decided metallic lustre; it crystallizes on sublimation and slow condensation in rhombohedra, isomorphous with those of antimony and tellurium.
It is a white solid which can be obtained crystalline by sublimation in a current of chlorine.
It seems to be a sublimation-product formed in volcanoes by the interaction of the vapour of ferric chloride and steam.