Historic lighthouse lenses weighing several tons rotated smoothly on circular troughs filled with mercury or later liquid lubricants. The massive Fresnel lenses floated on this ultra-low-friction surface, allowing a single person to push them by hand despite their enormous weight. Modern lighthouses now use ball bearings with synthetic oils, but some restored historic lighthouses still demonstrate the original mercury float system. This ingenious 19th-century engineering solution enabled continuous rotating beams visible for miles at sea.
Explore our lubricant product range
Explore our lubricant product range