The Collaborative International Dictionary of English v.0.48:

Slate \Slate\, v. t. [imp. & p. p. Slated; p. pr. & vb. n.
   Slating.]
   1. To cover with slate, or with a substance resembling slate;
      as, to slate a roof; to slate a globe.
      [1913 Webster]

   2. To register (as on a slate and subject to revision), for
      an appointment. [Polit. Cant]
      [1913 Webster]