slidometer

noun2

1. •
   An instrument for indicating and recording shocks to railway cars caused by sudden stopping.

   • The average shocks for the four stops were, by one slidometer, four-tenths of an inch and, by the other slidometer, five-tenths of an inch. — 1893
2. •
   A device for measuring the movement of a glacier.

   • A. Slidometer used to measure basal sliding rate. — 2002