A proposal for a lighthouse lens

France led developments in lighthouse technology in the 1820s, such as the groundbreaking combination of oil lamps and glass lenses developed by the French physicist Augustin-Jean Fresnel, that concentrated and intensified the light.

The world’s first working lighthouse lens was installed at Courdouan in 1823.

Norway’s first lens assembly was installed at Oksøy Lighthouse in 1832.

The so-called catadioptrical lighthouse lenses combine varying principles for the refraction of light through glass, collecting the beams from the light source in concentrated“cones”.

Each lighthouse got its own characteristic light by using a differing construc- tion of the lenses, and by having them rotate at differing speeds. To begin with the lenses were rotated using a clockwork assembly with weightslike those in a “grandfather’s clock”.