Experiments with persistent currents in saturated films of superfluid helium

Direct evidence for persistent currents in saturated films of superfluid helium has recently been presented. Prior to this several experiments had shown unexpected features which were subsequently shown to be consistent with the presence of persistent currents by the theoretical work of Campbell. The present work is an extension of earlier work and provides qualitative support for several of the characteristic film flow 'signatures' predicted by Campbell. (Auth.)