  We present several features of a cosmological model based on the
Brans-Dicke-Jordan-Thirry action which is scale invariant with a quartic
potential for the Jordan scalar field. We show that the radiation dominated era
starts with a closed universe which expands exponentially and the late
radiation dominated era expands linearly. We find that there may be a
scale-invariant phase with stiff matter between these two radiation dominated
eras. The introduction of matter in the linearly expanding universe causes
deceleration.
