normal pyrotartaric acid

from The Collaborative International Dictionary of English v.0.48

Glutaric \Glu*tar"ic\, a. [Glutamic + tartaric.] (Chem.)
   Of, pertaining to, or designating, an acid so called; as,
   glutaric ethers.
   [1913 Webster]

   {Glutaric acid}, an organic acid obtained as a white
      crystalline substance, isomeric with pyrotartaric acid; --
      called also {normal pyrotartaric acid}.
      [1913 Webster]