nitrum flammans

from The Collaborative International Dictionary of English v.0.48

Nitrum \Ni"trum\, n. [L., natron. See {Niter}.] (Old Chem.)
   Niter.
   [1913 Webster]

   {Nitrum flammans} [L., flaming niter] (Old Chem.), ammonium
      nitrate; -- probably so called because it deflagrates when
      suddenly heated.
      [1913 Webster]