This paper discusses
relations between a closed, convex set in a locally convex space and its normal cones
and barrier cone in the dual space. Results of Wu and de Andrade on the Gauss map
and spherical image of a convex hypersurface in a Hilbert space are generalized to the
topological vector space situation, and additional information is obtained on the
relation of the interior of the spherical image and barrier cone to the size and shape
of the given convex set.