Binary distillation experiments using the toluene-trichloroethylene system were conducted in a 3-in. diameter column packed with 0.25 in. Raschig rings. In order to determine the liquid phase mass transfer characteristics, gas absorption studies with CO 2-water system were also performed on the same column. It was shown in both cases that end-effects can be ettectively removed by using a “differential height” technique. It was observed in the distillation experiments that the liquid phase was saturated, indicating a negligible resistance to mass transfer in the liquid. Results from the absorption experiments indicate that this resistance is small but not negligible.