  The idea of contact angle was generalized by using the principle of minimum
total energy. The problems of the shape of the two-dimensional sessile drop and
the drop on an inclined surface are considered. The differential equations
describing the drop shapes are found in both cases. A case of good wetting is
considered to determine the profiles of the sessile and inclined drops. The
generalization of the boundary conditions for the contact angle hysteresis of
the drop on an inclined surface is discussed. The limit of the inclination
angle at which the drop begins to run down the inclined plane is found. The
models of the drop detachment from the solid and the motion of liquid inside of
the drop are discussed. This is not an original text.
