The Collaborative International Dictionary of English v.0.48:

Torsion meter \Torsion meter\ (Mech.)
   An instrument for determining the torque on a shaft, and
   hence the horse power of an engine, esp. of a marine engine
   of high power, by measuring the amount of twist of a given
   length of the shaft. Called also torsimeter, torsiometer,
   torsometer.
   [Webster 1913 Suppl.]