  Stability criterion for the surface gravity capillary waves in a flowing
two-layered fluid system with viscous dissipation is investigated. It is seen
that the dissipative instability of negative energy waves is absent,- contrary
to what earlier authors have concluded. Their error is identified to arise from
an erroneous choice of the dissipation law, in which the wave profile velocity
is wrongly equated to the particle velocity. Our corrected dissipation law is
also shown to restore Galilean invariance to the stability condition of the
system.
