  It is demonstrated that the measured spatial separation of two objects, at
rest in some inertial frame, is invariant under space-time transformations.
This result holds in both Galilean and Special Relativity. A corollary is that
there are no `length contraction' or associated 'relativity of simultaneity'
effects in the latter theory. A thought experiment employing four
unsynchronised clocks and a single measuring rod reveals that the physical
basis of the time dilatation effect is a relative velocity transformation law,
not `length contraction'. Time dilatation, which is universal and translation
invariant for all synchronised clocks at rest in any inertial frame, is the
unique space-time phenomenon discriminating Special from Galilean Relativity.
