We have recently considered cosmologies in which the Universal scale factor
varies as a power of the age of the Universe and concluded that they cannot
satisfy the observational constraints on the present age, the
magnitude-redshift relation for SN Ia, and the primordial element (D, He3, He4,
and Li7) abundances. This claim has been challenged in a proposal that
suggested a high baryon density model (Omega_B*h*h = 0.3) with an expansion
factor varing linearly with time could be consistent with the observed
abundance of primoridal helium-4, while satisfying the age and
magnitude-redshift constraints. In this paper we further explore primordial
nucleosynthesis in generic power-law cosmologies, including the linear case,
concluding that models selected to satisfy the other observational constraints
are incapable of accounting for all the light element abundances.Comment: Matches version accepted for publication in Phys. Rev.
