{HEAD ~ a first vibration generator} positioned against {TAIL ~ the first container wall} so that, when the first vibration generator is activated, vibrations including a first selected frequency are produced by the first vibration generator and pass into the chemical bath liquid contained in the container at the first container wall; and 
{ HEAD ~ a first vibration generator } positioned against { TAIL ~ the first container wall } so that , when the first vibration generator is activated , vibrations including a first selected frequency are produced by the first vibration generator and pass into the chemical bath liquid contained in the container at the first container wall ; and
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH