  As an application of universal polynomials for local and multi-singularities
of maps, we revisit classical enumerative formulae of Salmon-Cayley-Zeuthen for
projective surfaces and analogous formulae of Segre-(B.)Severi-Roth for
projective $3$-folds. In particular, several examples of actual computation are
given using universal polynomials for computing weighted Euler characteristics
of singularity loci.
