The Collaborative International Dictionary of English v.0.48:

Reometer \Re*om"e*ter\ (r?-?m"?-t$r), n.
   Same as Rheometer.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Rheometer \Rhe*om"e*ter\, n. [Gr. "rei^n to flow + -meter.]
   [Written also reometer.]
   1. (Physics) An instrument for measuring currents, especially
      the force or intensity of electrical currents; a
      galvanometer.
      [1913 Webster]

   2. (Physiol.) An instrument for measuring the velocity of the
      blood current in the arteries.
      [1913 Webster]