The Collaborative International Dictionary of English v.0.48:

Ballast \Bal"last\, v. t. [imp. & p. p. Ballasted; p. pr. &
   vb. n. Ballasting.]
   1. To steady, as a vessel, by putting heavy substances in the
      hold.
      [1913 Webster]

   2. To fill in, as the bed of a railroad, with gravel, stone,
      etc., in order to make it firm and solid.
      [1913 Webster]

   3. To keep steady; to steady, morally.
      [1913 Webster]

            'T is charity must ballast the heart. --Hammond.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Ballasting \Bal"last*ing\, n.
   That which is used for steadying anything; ballast.
   [1913 Webster]