Fig. 5. Average values, unnormalized (left axis) and normalized by the clay cation exchange capacity (right axis), for the amount of water adsorbed by Blount and Fayette soil clays at P/P₀ 0.5 as a function of hydration energy of the exchangeable cations per mole of charge (Table 4). Solid lines correspond to linear regressions for Blount (y = 0.1647x + 7.2470, R² = 0.99) and Fayette clay (y = 0.2636x – 16.2440, R² = 0.98) using unnormalized data; the dashed line corresponds to the combined regression for both soil clays using normalized data (y = 0.0063x – 0.0316, R² = 0.98).