The lens assembly is among the largest in existence, a so called lens of the first order, of French manufacture.
This was invented in 1823. Augustin Fresnels breakthrough has meant a lot for the development of lighthouse technology.
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“In 1823 Augustin Fresnel’s refractive glass lens was brought into use for the first time at the Corduan lighthouse outside Bordeaux. The lens revolutionised the development of lighthouse lights world-wide. It was now possible to gather the light as a compressed bundle of beams or send it out as a horizontal light-belt. The lighthouse lights became visible at longer distances…” Source: Wikipedia