Water is depressed in a glass tube whose inner surface is cotated with paraffin wax. Why?

Why water gets depressed in a glass tube whose inner surface is coated with wax?

Water rises in a glass capillary tube, but descends if the bore of the capillary tube is coated with paraffin wax. Why ?

The surface of water in contact with glass wall is

The surface of water in contact with glass wall is

Water spreads on a glass surface but it forms beads on a glass surface polished by paraffin-why?

Water meniscus in a glass tube is concave while that of mercury is convex. Why ?

Water meniscus in a glass tube is concave while that of mercury is convex. Why ?