  We expand the notion of a normal function for a Hodge class on an
even-dimensional complex projective manifold to the notion of a 'topological
normal function' associated to any primitive integral cohomology class. The
definition of the intersection number of two topological normal functions is
the analogue of that given by Griffiths and Green for classical normal
functions. We give a simple proof that the intersection number of the normal
functions is the same as the intersection number of their corresponding
cohomology classes.
