I have learnt two derivations to calculate the height of the liquid column in a narrow capillary. Here is a derivation using forces and equilibrium :
This is the exact derivation given in my book. But I don't quite understand one thing. My book just states that the forces shown in red are '' forces due to surface tension ''. Who actually exerts these forces on the liquid in contact with the glass, and in what direction?
It cannot be the liquid because then this force wouldn't be included in the free body diagram of the liquid itself.
So it has to be because of the solid. But, these forces are the adhesive forces, and I have learnt that the adhesive forces acting on the liquid act along the normal to the surface of the solid and liquid, and point towards the solid. So how can the adhesive forces be responsible for supporting the weight of the liquid column if they do not have a vertical component?