The Collaborative International Dictionary of English v.0.48:

Sulphureous \Sul*phu"re*ous\, a. [L. sulphureus, sulfureus.]
   Consisting of sulphur; having the qualities of sulphur, or
   brimstone; impregnated with sulphur.
   [1913 Webster]

         Her snakes united, sulphureous waters drink. --Pope.
   [1913 Webster] -- Sul*phu"re*ous*ly, adv. --
   Sul*phu"re*ous*ness, n.
   [1913 Webster]