Lubrication of the ship steam enginecrankshaft. The two bottles of lubricant are attached to the piston and move while the engine is operating.
Lubrication is a physicalprocess which allows surfaces to move smoothly against each other. A thin film of lubricant put between the surfaces reduces friction and wear on the surfaces, and keeps temperatures from rising too far. The lubricant film can be a solid/liquiddispersion, a liquid, a liquid-liquid dispersion (a grease) or, exceptionally, a solid or gas.
