The Collaborative International Dictionary of English v.0.48:

Refracting \Re*fract"ing\, a.
   Serving or tending to refract; as, a refracting medium.
   [1913 Webster]

   Refracting angle of a prism (Opt.), the angle of a
      triangular prism included between the two sides through
      which the refracted beam passes in the decomposition of
      light.

   Refracting telescope. (Opt.) See under Telescope.
      [1913 Webster]