The Collaborative International Dictionary of English v.0.48:

Epistolographic \E*pis`to*lo*graph"ic\, a. [Gr. ?: cf. F.
   ['e]pistolographique.]
   Pertaining to the writing of letters; used in writing
   letters; epistolary.
   [1913 Webster]

   Epistolographic character of writing or Epistolographic
   mode of writing, the same as Demotic character. See under
      Demotic.
      [1913 Webster]