  Superconductors are the only experimentally accessible systems with
spontaneously broken gauge symmetries which support topologically nontrivial
defects, namely string defects. We propose two experiments whose aim is the
observation of the dense network of these strings thought to arise, via the
Kibble mechanism, in the course of a spontaneous symmetry breaking phase
transition. We suggest ways to estimate the order of magnitude of the density
of flux tubes produced in the phase transition. This may provide an
experimental check for the theories of the production of topological defects in
a spontaneously broken gauge theory, such as those employed in the context of
the early Universe.
