●●● ●●●● ●●●●● 4. Experimental procedures ●●●● ●●●●● ●●●● .(2) Put some distilled water into the external case(regard as liquid of known IFT. See Appendix ll to get its surface tension). Insert the capillary tube into the external case and plug the plug tightly and let the tip of the capillary tube touch the liquid surface exactly. read out the zero level ho of the tube beneath the inclined tube manometer (at this point both ends of the inclined tube manometer connect with the atmosphere). Install the device according to figure2 1, where the separatory funnel is filled with tap water.4.Experimental procedures ⚫ (2)Put some distilled water into the external case(regard as liquid of known IFT. See Appendix II to get its surface tension).Insert the capillary tube into the external case and plug the plug tightly and let the tip of the capillary tube touch the liquid surface exactly.Read out the zero level h0 of the tube beneath the inclined tube manometer(At this point both ends of the inclined tube manometer connect with the atmosphere).Install the device according to figure2- 1,where the separatory funnel is filled with tap water