I. Perspectives on the Mechanism of Osmosis and Imbibition.- I. The Founders.- II. Thermodynamic Laissez Faire.- III. Some Fundamental Experimental Facts.- IV. Water Tension Theory.- V. Water Concentration Theory.- Pressure Drop at the Pore Openings.- Osmotic Flow against the Water Potential.- Anti-Gravity Devices in Trees.- Comments.- Concluding Remarks.- II. Some Reversible Thermodynamic Relationships at Equilibrium.- Some Basic Thermodynamic Statements.- The Poynting Relation.- The Clapeyron Equation.- Application of Thermodynamic Statements to Solutions.- Ideal Solution.- Interpreting the Change in Chemical Potential of a Solvent Homogeneous in a Solution.- III. Toward Understanding the Colligative Properties of a Solution.- I. Osmotic Pressure.- Distribution of Vapor Molecules in a Gravity Field.- Thermal Pressure of the Solute and Solvent Molecules within the Solution.- Induction of Enhanced Tension in the Solvent of a Solution.- Distribution of Solute Molecules within a Solution in a Gravity Field.- The Weight of the Column Below the Surface of the Solution and its Correlation with the Concentration at the Free Surface and the Osmotic Pressure of the Solution.- Vapor Pressure of a Distensible Liquid under Tension.- Summary of the Conditions which Describe the Solution in a Gravity Osmometer shown in Figs. 52 and 53.- The Greater Tension in the Solvent within a Solution Alters its Osmotic Pressure with Respect to Pure Solvent.- Height of Solution Column in a Cylindrical Gravity Osmometer.- II. Vapor Pressure.- III. Melting Point.- IV. Boiling Point.- IV. The Chemical Potential of Water.- In a Solution.- In a Matrix.- Chemical Potential of Solvent in Real Solutions.- Glossary of Terms.- References.