verticity

from The Collaborative International Dictionary of English v.0.48

Verticity \Ver*tic"i*ty\, n. [Cf. F. verticit['e]. See
   {Vertex}.]
   The quality or power of turning; revolution; rotation. [R.]
   --Locke.
   [1913 Webster]

         I hardly believe he hath from elder times unknown the
         verticity of the loadstone.              --Sir T.
                                                  Browne.
   [1913 Webster]