  In this paper, by considering dual geodesic trihedron (dual Darboux frame) we
define dual Smarandache curves lying fully on dual unit sphere S^2 and
corresponding to ruled surfaces. We obtain the relationships between the
elements of curvature of dual spherical curve (ruled surface) x(s) and its dual
Smarandache curve (Smarandache ruled surface) x1(s) and we give an example for
dual Smarandache curves of a dual spherical curve.
