  High-pressure resistivity experiments were performed on the recently
discovered superconductor, MgB2. Tc decreases quasi-linearly with applied
pressure to 1.4 GPa at a rate of -2.0(1) K/GPa, which is somewhat larger than
that derived from recently-reported ac susceptibility measurements. The
reduction of Tc is consistent with the BCS picture, in a similar way to the
C60-based superconductors. Taking into account the pressure dependence of the
unit cell volume, V, the volume coefficient of Tc, d(lnTc)/dV is significantly
large.
