Observation of mass transport through solid 4He

By use of an experimental design that provides for superfluid helium in contact with bulk hcp He-4 off the melting curve, we have observed the dc transport of mass through a cell filled with solid He-4 in the hcp region of the phase diagram. Flow, which shows characteristics of a superflow, is seen to be independent of the method used to grow the solid but depends on pressure and temperature. The temperature dependence suggests the possibility of hysteresis.