  We investigate the accuracy of the frozen--flow approximation (FFA), recently
proposed by Matarrese \etal (1992), for following the nonlinear evolution of
cosmological density fluctuations under gravitational instability. We compare a
number of statistics between results of the FFA and nbody simulations,
including those used by Melott, Pellman \& Shandarin (1993) to test the
Zel'dovich approximation. The FFA performs reasonably well in a statistical
sense, e.g. in reproducing the counts--in--cell distribution, at small scales,
but it does poorly in the crosscorrelation with nbody which means it is
generally not moving mass to the right place, especially in models with high
small--scale power.
