It occurs between solids and solids, liquids and solids, liquids and liquids, gases and solids, gases and gases, and gases and liquids.
Adhesion is supposed to manifest itself at an appreciable distance before actual contact of bodies.
The ascent of liquids in capillary tubes is a result of adhesion, as well as the spreading out of liquids between two surfaces kept in close proximity. The chain-pump, in which the water is carried up by a simple chain in a tube, is a practical example of adhesion of liquids to solids. The adhesion of gases and solids, is illustrated by the adhesion of air around a piece of solid iron, which causes it to float on melted iron. In the Giffard injector a blast of steam is used to carry water by its adhesion to it into the boiler against its own pressure. The adhesive force on railroads may be estimated approximately by multiplying the weight of the locomotive in tons which rests on the driving-wheels by a coefficient of adhesive for said wheels.