Seguin Island Light the only lighthouse north of Virginia with the original First Order Fresnel Lens. Block Island Light in Rhode Island had a new lens intalled in 1929 and in 2017 Graves Light in Boston Harbor had a First -order Fresnel Lens installed using lens from other antique lenses.
In 1853, is was recommended by the Lighthouse Board that the new tower should be a First Order Station because of the importance of shipping on the Kennebec and Sheepscott Rivers. When the new/current tower was erected, the rare First Order Lens was installed.
The lens first devised by Augustin Fresnel (pronounced fraynel) (1788-1827) is a beehive shape of concentric annular sections that cast parallel beams of light. Comprised of 282 individual prisms, the first order lens can cast a beam of light that can be seen from more than 20 miles. Seguin’s lens was crafted by Henry Lapaute of Paris and installed in 1857. The original lamp was lit by kerosene and burned about 2 gallons per hour. In 1907 it was changed to vaporize the oil and the wicks were replaced by a mantle. In the 1950’s electricity came to the island and the lamp was replaced by a thousand watt high powered electric bulb, which is still in use today.
The lens is 9’ tall and 6’ wide. It is hard to imagine, but at 136′ the whole tower sways in the wind unnoticeably .
The keeper’s wives had to clean all the prisms of the lens regularly. A shard of the glass protecting the lamps in the original 1795 wooden tower is on display in a case in the museum. The original dimensions of the octagon wooden 1795 tower are marked in the ground at the original tower site.