  The Nos\'e-Hoover dynamics for isothermal-isobaric (NPT) computer simulations
do not generate the appropriate partition function for ergodic systems. The
present paper points out that this can be corrected with a simple addition of a
constant term to only one of the equations of motion. The solution proposed is
much simpler than previous modifications done towards the same goal. The
present modification is motivated by the work virial theorem, which has been
derived for the special case of an infinitely periodic system in the first part
of this paper.
