The Collaborative International Dictionary of English v.0.48:

Counterbalance \Coun`ter*bal"ance\ (-b?l"ans), v. t. [imp. & p.
   p. Counterbalanced (-anst); p. pr. & vb. n.
   Counterbalancing.]
   To oppose with an equal weight or power; to counteract the
   power or effect of; to countervail; to equiponderate; to
   balance.
   [1913 Webster]

         The remaining air was not able to counterbalance the
         mercurial cylinder.                      --Boyle.
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         The study of mind is necessary to counterbalance and
         correct the influence of the study of nature. --Sir W.
                                                  Hamilton.
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