  We provide a gauge-invariant theory of gravitation in the context of Weyl
Integrable Space-Times. After making a brief review of the theory's postulates,
we carefully define the observers' proper-time and point out its relation with
space-time description. As a consequence of this relation and the theory's
gauge symmetry we recover all predictions of General Relativity. This feature
is made even clearer by a new exact solution we provide which reveals the
importance of a well defined proper-time. The thermodynamical description of
the source fields is given and we observe that each of the geometric fields
have a certain physical significance, despite the gauge-invariance. This is
shown by two examples, where one of them consists of a new cosmological
constant solution. Our conclusions highlight the intimate relation among test
particles trajectories, proper-time and space-time description which can also
be applied in any other situation, whether or not it recovers General
Relativity results and also in the absence of a gauge symmetry.
