Figure 5-9

Liquid between vertical rails with gravity.

The contact angle on both rails is 20 degrees. The gap between the rails is 4/5 the height of the rails, so the liquid advances since cos 20 > 4/5. But in this model the dimensions are millimeters rather than micrometers, so gravity starts to become important. The gap is 4 mm and the rails are 5 mm high, and the liquid is water.