  In the present paper it is considered a class V of 3-dimensional Riemannian
manifolds M with a metric g and two affinor tensors q and S. It is defined
another metric \bar{g} in M. The local coordinates of all these tensors are
circulant matrices. It is found:
  1)\ a relation between curvature tensors R and \bar{R} of g and \bar{g},
respectively;
  2)\ an identity of the curvature tensor R of g in the case when the curvature
tensor \bar{R} vanishes;
  3)\ a relation between the sectional curvature of a 2-section of the type
\{x, qx\} and the scalar curvature of M.
