.
If it should be deemed desirable to include the cohesion acting upward along the vertical planes,
, etc., it is very readily done. At each point, such as
, draw vertically upward a line of length (to scale of force)
lb., to represent the force of cohesion acting along the corresponding plane. From the extremities of such lines, parallels to
are drawn to the intersections with the corresponding rays, of the type,