Two new versions (NpH and mu VL) of the Gibbs ensemble Monte Carlo sim
ulation for pure fluids are suggested. These procedures allow the chan
ge of heat between the correlated subsystems. In the determination of
the vapour-liquid coexistence, the capability of the new algorithms is
similar to that of the original (NVT) method, however, in the determi
nation of the vapour pressure curves, the NpH version has some advanta
ge over the others.