locate above line 50 rather than at the line is a function of the surface tension of the liquid the surface energetics of surface 42 and most especially the rate of withdrawal of the probe the slower the withdrawal rate the more likely it is that liquid l 39 will locate above line 50 there is no basic limit on how slowly the probe and container are to be withdrawn from the liquid fig3 practical considerations dictate of course the most rapid rate that can be tolerated preferably for best results the rate does not exceed about 4 0 cm sec unless surface 42 is treated with a surfactant as described hereinafter the success of the portion 34 in drawing sheath s away from portion 32 is believed to be due to the increased rate of increase in surface area of the cone fragment that comprises portion 34 such increased rate of increasing surface area is reflected in the increased rate of increasing effective circumferences for that portion that is liquid on this portion 34 sees 34 an ever increasing surface area as it moves a greater distance away from orifice 40 beyond line 50 axis 34 x 34 fig2 for a given amount of liquid volume an increasing supportive surface area means an increase in the radius of curvature of the liquid.