Fig. 1. Zisman plot (cosine of the experimentally derived contact angle, cos_E, vs. the liquid–vapor surface tension, _LV) for water and aqueous ethanol solutions. Filled and open points are for _E measured by means of the Wilhelmy plate method (WPM) and the weight-gain capillary rise method (CRM), respectively. The dashed straight line and solid line for the logistic curve (Eq. [17]) were calculated from the combined data of WPM and CRM. The leftmost point in each graph represents the assumed data _E = 0 for pure ethanol. OR = orange orchard cover soil; PN = pine cover soil; EP = eucalyptus cover soil; LCh and PCh = organic matter extracted from leonardite and sphagnum moss, respectively, with chloroform; and LEt and PEt = organic matter extracted from leonardite and sphagnum moss, respectively, with ethanol.