The Fresnel Lens: History & Pomham Rocks Lighthouse

Written by Kate Gilbert

The Fresnel Lens has been an unwavering object at the Custom House Maritime Museum since it was installed in the late 1970’s. Many people have seen it lit at night while strolling the boardwalk, while out in the harbor in their boat, or while visiting the museum. Many of our visitors, and the residents of Newburyport, may well believe that the lens is in the permanent collection of the Museum. However, through our wonderful relationship with the US Coast Guard, the Fresnel lens has actually been on loan to us for almost 40 years. Installed in the downstairs hallway, it lit our visitors paths for decades as a symbol of the merchant shipping industry in Newburyport, and an homage to our very own lighthouses. After such a wonderful extended engagement, it is now time for our beloved Fresnel Lens to make its way back to its original home: the Pomham Rocks Lighthouse in Riverside, Rhode Island.

Our 4th Order Fresnel Lens was originally installed in the Popham Rocks Lighthouse in 1926, and it was used there until June 1974 when the lighthouse was decommissioned by the United States Coast Guard. The Friends of Pomham Rocks Lighthouse is a 501(c)3 non-profit that was established in 2004 to restore and maintain the 1871 historic landmark. We, as a Museum, believe that this Fresnel lens would better serve the Friends of Pomham Rocks Lighthouse as they work to ensure the historic restoration and preservation of Pomham Rocks Lighthouse. While we have had the pleasure of being good stewards of this
object for the time that we have had with it, we feel that this lens is an integral part of their history and it fulfills their mission clearer than our own. As a professional Museum, it would be an unethical decision to keep it at this site purely for sentimental value (no matter how much we will miss it!).

The Pomham Rocks Lighthouse was first lit on December 1, 1871 with a sixth order Fresnel lens showing a fixed white light. Just over a year later, the color was changed to a fixed red light, which it remains today. That 6 th order Lens was replaced by our beloved 4 th Order Fresnel Lens as an upgrade in 1926. The Fresnel lens is a compact lighthouse lens developed by French physicist Augustin-Jean Fresnel (1788–1827). Fresnel produced six sizes of lighthouse lenses divided into four ‘orders’ based on their size and focal length, First-Order being the largest. The lens uses prisms arranged in concentric circles, which
greatly reduced the size and weight of the lens, and were far more powerful, throwing light much further than previous lighthouse lens designs. Although we currently broadcast a white light through it, it always broadcasted a red light while it was placed at the Pomham Rocks Lighthouse.

The lighthouse itself was operated by six civilian lightkeepers, before the Coast Guard took over operations in 1956, and operated through 1974. In 1978, the property was purchased by the Mobil Oil Corporation with the intent of preservation. In 2000, the now Exxon Mobil Corp was approached by local citizens regarding the possibility of a partnership to restore
the lighthouse to its 1871 condition, to which they happily agreed, and even funded a large part of it. That is when the Friends of Pomham Rocks Lighthouse was formed, and the historic preservation began. In 2006, the lighthouse was relit after having been dark for 32 years. Exxon Mobil Corp transferred ownership of the island and its buildings by donating them to the American Lighthouse Foundation in 2010, and since then, numerous preservation activities have been completed. Reacquiring the Fresnel Lens would be a huge coup for their society and would help to give real meaning to their preservation activities. We, as the Custom House Museum, do hope that the public shares in our excitement as this wonderful object is finally returned home.

Plan Your Visit

Museum Hours

Tuesday - Saturday: 10 am - 5 pm
Sunday: 12 pm - 5 pm
Closed Monday

Tickets

$8 admission for adults
Suggested $5 donation for Newburyport residents.
Free for kids under 12 and museum members

Cost of admission includes access to the Discovery Center.

Parking

City parking is available adjacent to the museum.
View parking lot directions.