 
The pictures show the first lighthouse lens in the world, which was a dioptric annular lens constructed and manufactured by Augustin Frensel. It was installed in the year of 1823 on the lighthouse Cordouan situated at the mouth the river Gironde off Bordeuax in France. Above and below the lens are a number of mirrors placed in order to magnify the light. The lens can nowadays be looked at in the French lighthouse museum at the Creach lighthouse on the southern part of the Ouessant island (situated west of Bretange.) |
