LAUSR

Measurements that document a number of the characteristics of $$^{4}\hbox {He}$$  mass flux through a cell filled with solid $$^{4}\hbox {He}$$  carried out at the University of Massachusetts and elsewhere are reviewed. The mass flux is found to be a universal function of temperature, to have nonlinear behavior as a function of the driving chemical potential as might be expected for a Luttinger liquid and the flux can be extinguished at a concentration-dependent temperature by the presence of $$^{3}\hbox {He}$$  . Strong evidence indicates that the flux is carried by the cores of dislocations present in the solid. Some contact with the history of quantum fluids and relevant early work in solid helium is made as is contact with theory related to the notion of a supersolid and mass flux in $$^{4}\hbox {He}$$  .