\Sul"phur\, n. [L., better sulfur: cf. F. soufre.]
1. (Chem.) A nonmetallic element occurring naturally in large
   quantities, either combined as in the sulphides (as
   pyrites) and sulphates (as gypsum), or native in volcanic
   regions, in vast beds mixed with gypsum and various earthy
   materials, from which it is melted out. Symbol S. Atomic
   weight 32. The specific gravity of ordinary octohedral
   sulphur is 2.05; of prismatic sulphur, 1.96.
Note: It is purified by distillation, and is obtained as a
      lemon-yellow powder (by sublimation), called flour, or
      flowers, of sulphur, or in cast sticks called roll
      sulphur, or brimstone. It burns with a blue flame and a
      peculiar suffocating odor. It is an ingredient of
      gunpowder, is used on friction matches, and in medicine
      (as a laxative and insecticide), but its chief use is
      in the manufacture of sulphuric acid. Sulphur can be
      obtained in two crystalline modifications, in
      orthorhombic octahedra, or in monoclinic prisms, the
      former of which is the more stable at ordinary
      temperatures. Sulphur is the type, in its chemical
      relations, of a group of elements, including selenium
      and tellurium, called collectively the sulphur group,
      or family. In many respects sulphur resembles oxygen.
2. (Zo["o]l.) Any one of numerous species of yellow or orange
   butterflies of the subfamily {Pierin[ae]}; as, the clouded
   sulphur ({Eurymus, or Colias, philodice}), which is the
   common yellow butterfly of the Eastern United States.
{Amorphous sulphur} (Chem.), an elastic variety of sulphur of
   a resinous appearance, obtained by pouring melted sulphur
   into water. On standing, it passes back into a brittle
   crystalline modification.
{Liver of sulphur}. (Old Chem.) See {Hepar}.
{Sulphur acid}. (Chem.) See {Sulphacid}.
{Sulphur alcohol}. (Chem.) See {Mercaptan}.
{Sulphur auratum} [L.] (Old Chem.), a golden yellow powder,
   consisting of antimonic sulphide, {Sb2S5}, -- formerly a
   famous nostrum.
{Sulphur base} (Chem.), an alkaline sulphide capable of
   acting as a base in the formation of sulphur salts
   according to the old dual theory of salts. [Archaic]
{Sulphur dioxide} (Chem.), a colorless gas, {SO2}, of a
   pungent, suffocating odor, produced by the burning of
   sulphur. It is employed chiefly in the production of
   sulphuric acid, and as a reagent in bleaching; -- called
   also {sulphurous anhydride}, and formerly {sulphurous
   acid}.
{Sulphur ether} (Chem.), a sulphide of hydrocarbon radicals,
   formed like the ordinary ethers, which are oxides, but
   with sulphur in the place of oxygen.
{Sulphur salt} (Chem.), a salt of a sulphacid; a sulphosalt.
{Sulphur showers}, showers of yellow pollen, resembling
   sulphur in appearance, often carried from pine forests by
   the wind to a great distance.
{Sulphur trioxide} (Chem.), a white crystalline solid, {SO3},
   obtained by oxidation of sulphur dioxide. It dissolves in
   water with a hissing noise and the production of heat,
   forming sulphuric acid, and is employed as a dehydrating
   agent. Called also {sulphuric anhydride}, and formerly
   {sulphuric acid}.
{Sulphur whale}. (Zo["o]l.) See {Sulphur-bottom}.
{Vegetable sulphur} (Bot.), lycopodium powder. See under
   {Lycopodium}.