historionomer

from The Collaborative International Dictionary of English v.0.48

Historionomer \His*to`ri*on"o*mer\, n. [Gr. ? history + ? to
   distribute.]
   One versed in the phenomena of history and the laws
   controlling them.
   [1913 Webster]

         And historionomers will have measured accurately the
         sidereal years of races.                 --Lowell.
   [1913 Webster]