Hog Island Lighthouse First Order Fresnel Lens

French civil engineer and physicist Augustin-Jean Fresnel invented the lens that bears his name in 1822. By combining reflecting and refracting prisms, he allowed lighthouses to focus light that'd normally scatter into a single beam. It allowed them to produce patterns to signal ships at sea, improving coastal navigation and saving countless lives.

Fresnel Lenses are divided into 6 different sizes known as orders, with the 1st being the largest and the 6th being the smallest. This particular Fresnel Lens is the 2nd largest of its kind in the world.