  We show that the specific heat of the superconductor MgB_2 (MgB2) in zero
field, for which significant non-BCS features have been reported, can be
fitted, essentially within experimental error, over the entire range of
temperature to T_c by a phenomenological two-gap model. The resulting gap
parameters agree with previous determinations from band-structure calculations,
and from various spectroscopic experiments. The determination from specific
heat, a bulk property, shows that the presence of two superconducting gaps in
MgB_2 is a volume effect.
