The Collaborative International Dictionary of English v.0.48:

Mediately \Me"di*ate*ly\, adv.
   In a mediate manner; by a secondary cause or agent; not
   directly or primarily; by means; -- opposed to immediately.
   [1913 Webster]

         God worketh all things amongst us mediately. --Sir W.
                                                  Raleigh.
   [1913 Webster]

         The king grants a manor to A, and A grants a portion of
         it to B. In this case. B holds his lands immediately of
         A, but mediately of the king.            --Blakstone.
   [1913 Webster]