The Present work was undertaken for the purpose of observing watted area of packing materials in the packed columns. Studies were made on two kinds of Raschig rings by using a dyestuff. The schematic diagram of experimental apparatus is shown in Fig. 1-A and the specifications of Raschig rings are listed in Table 1. The gas rate and viscosity of the liquid had no significant effect on wetted area. The effects of liquid rate and surface tension of the liquid used are as follows : (수식) The values of a_w/a_t varied with the packing height to the-0.05 power for all packing materials.