An experimental investigation of double-diffusive convection in a two-layer, salt-stratified solution destabilized by lateral heating and cooling has been performed. Initially, diffusive regime phenomena are observed as the two uniform salinity layers are thermally driven and behave somewhat independently. As salt is transferred across the interface separating the layers, salinity stabilization decreases and complicated flow structure is observed at the interface. In the final stages before mixing, the stabilizing salinity gradient becomes small, the thermal/hydrodynamic boundary layers on the heated and cooled sidewalls penetrate the salinity interface and mixing, in the finger regime, occurs. The dimensionless mixing time is described with parameters associated with thermal and salinity buoyancy forces and the enclosure aspect ratio. Careful selection of the experimental conditions allows dimensionless interfacial salinity transport rates to be correlated with appropriate dimensionless parameters.