Interferometric investigation of the polarographic maxima

The flow patterns around the mercury drop at the positive and negative polarographic maxima have been investigated by suspensions of activated carbon particles and laser interferometry. The accepted patterns due to Antweiler have been shown to require modification. Specifically the positive maximum flow is a downflowing annulus with a gently upwelling interior below the equator of the drop and the negative maximum flow is a torroidal whorl surrounding the drop. Speeds of particles were recorded by motion picture photography and concentration changes by interferograms.