  We consider a four dimensional Riemannian manifold M with a metric g and
affinor structure q. The local coordinates of these tensors are circulant
matrices. Their first orders are (A, B, C, B), A, B, C\in FM and (0, 1, 0, 0),
respectively.
  We construct another metric \tilde{g} on M. We find the conditions for
\tilde{g} to be a positively defined metric, and for q to be a parallel
structure with respect to the Riemannian connection of g.
  Further, let x be an arbitrary vector in T_{p}M, where p is a point on M. Let
\phi and \phi be the angles between x and qx, x and q^{2}x with respect to g.
We express the angles between x and qx, x and q^{2}x with respect to
$\tilde{g}$ with the help of the angles $\phi$ and \phi.
  Also,we construct two series {\phi_{n}}and {\phi_{n}}. We prove that every of
it is an increasing one and it is converge.
