Fresnel Lens Building at the Fire Island Lighthouse, Fire Island National Seashore
Part of the Fire Island Lighthouse complex is a barn-like structure known as the Fresnel Lens Building. It houses the original Fresnel Lens used in the second Fire Island Lighthouse, the one standing today. In 1821, Augustin Fresnel invented a revolutionary new lens system and developed four different sizes, or orders. More orders have been designed since its initial conception, and there are now eleven in total. The lens installed in the Fire Island Lighthouse in 1858 was a First Order lens, which was the largest size available.
The original Fresnel Lens was removed in 1933. It was disassembled and shipped to the Franklin Institute in Philadelphia where it was put on display from 1939 all the way until 2000. When the lens exhibit ended, it was once again disassembled and put into storage. Fire Island National Seashore and the Fire Island Lighthouse Preservation Society negotiated to borrow the lens on a long-term loan, but it took another ten years for funds to be raised for a new museum to house the lens.
In July 2011, the Fresnel Lens Building opened, and the lens could once again be viewed by the public. The museum sits on the location of an old steam powered generator building that was built in 1896 during an initial effort to convert the lighthouse to electricity, a plan that was later cancelled. The building was designed to look like the old generator building, though much larger.
There is no charge to enter the Fresnel Lens Building, and it is open whenever the lighthouse itself is open. Get the latest schedule on the Fire Island Lighthouse Preservation Society’s Visit Fire Island Lighthouse web page. This organization owns and operates the lighthouse, not the National Park Service.
Original First Order Fresnel Lens from the Fire Island Lighthouse on display in the Fresnel Lens Building, Fire Island National Seashore
The original Fresnel Lens was replaced with a newer First Order lens that had been in the former Shinnecock Lighthouse. This one differed from the original in that it sat in a mercury-filled basin that allowed it to rotate faster and flash every 7.5 seconds instead of every 60 seconds as did the original. The original lens sat on what are known as Chariot Wheels: bronze or steel wheels that rolled in a circle along a steel track. Friction between the wheels and track resulted in a slow rotation speed, whereas friction was negligible in a liquid-based rotation system. The original lens not sits on the original Chariot Wheels, and along with the two is the Rotation Clockwork, the machine responsible for the turning of the lens.
Original Rotation Clockwork from the Fire Island Lighthouse on display in the Fresnel Lens Building, Fire Island National Seashore
Another item on display is an original Incandescent Oil Vapor Lamp (IOVL) that was installed in the Fire Island Lighthouse in 1907. The IOVL provided the fuel for the flame by using air pressure to vaporize kerosene, a method that allowed the flame to burn three times brighter than the previous Funck Lamp. The IOVL system is comprised of the incandescent oil vapor lamp itself and a pneumatic pressurized fuel tank. For display purposes, the original lamp is now mounted on an original hydraulic oil reservoir, though the reservoir played no part in the operation of the IOVL (it was used as part of an earlier lamp system and is shown on the right in the photo below). The pneumatic pressurized tank is a reproduction.
Incandescent Oil Vapor Lamp on display in the Fresnel Lens Building next to the Fire Island Lighthouse, Fire Island National Seashore
In 1949, the second Fresnel Lens was replaced by a custom-made beacon light manufactured by Crouse-Hinds. It was used until the Fire Island Lighthouse was decommissioned on December 31, 1973. At that time that lighthouse tower had deteriorated so much that the Coast Guard did not consider it to be worth fixing. The original Crouse-Hinds light is no housed in the Fresnel Lens Building.
Original Crouse-Hinds light used from 1949 to 1974 in the Fire Island Lighthouse
Next to the Crouse-Hinds lens is a Fourth Order Fresnel Lens. This was never used in the Fire Island Lighthouse, but it demonstrates the difference in the size between the First and Fourth Order lenses.
Fourth Order Fresnel Lens on display in the Fresnel Lens Building, Fire Island National Seashore
Original First Order Fresnel Lens installed in the Fire Island Lighthouse on display in the Fresnel Lens Building, Fire Island National Seashore
Other items on display in the Fresnel Lens Building include a Multi-Wick Burner and an interactive Fresnel Lens and Rotation Clock that visitors can crank to see how the lens turned without electric power. (Note: In the second photo below, the Multi-Wick Burner is the item above the identification card, and a lamp sits atop it. The burner is attached to a hydraulic oil reservoir, which in this display, is in the proper context.)
Interactive Fresnel Lens and Rotation Clock at the Fresnel Lens Building, Fire Island National Seashore
Multi-wick Burner and hydraulic oil reservoir on display in the Fresnel Lens Building, Fire Island National Seashore
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Last updated on June 18, 2026
