By Gail McCarthy
---- — A mammoth lighthouse lens, which served as a beacon for mariners for more than 120 years, is now the focus of an effort to bring this piece of history back to Cape Ann.
The Cape Ann Museum and the Thacher Island Association have teamed up to return a Fresnel lens, which is 10 feet tall and 6 feet in diameter, and oversee its restoration and house it permanently at the museum.
The one-ton lens was made in Paris in 1860 and is comprised of more than 1,000 glass prisms set in a bronze frame. The lens was once housed in Thacher Island’s South Tower and later called Cape Ann Light. The 50-acre Thacher Island is home to twin lighthouses, of which there are only a few remaining in the country. The lighthouses themselves pre-date the Revolutionary War, having been erected in 1771.
The light was fueled first by whale oil, then by lard oil, and eventually kerosene. In 1860, work began to rebuild the towers to accommodate and support the newest in lighting technology with the installment of the first-order Fresnel lens.
“During the 1850s most of America’s lighthouses received Fresnel lenses that improved their efficiency tremendously,” according to the Thacher Island Association’s website. “It was decided that new, taller towers were needed ... Twin towers, 124 feet high, were built. The twin lighthouses were fitted with enormous first-order Fresnel lenses, which cost $10,000 each. The new towers were first illuminated on October 1, 1861.”
Invented in the early 1820s by French physicist Augustine-Jean Fresnel, a Fresnel lens could cast a much greater beam of light than previous lenses. “On Thacher Island, this meant the light could be seen 22 miles at sea, triple the distance of earlier lights,” according to a museum press release.
The lens was electrified in 1932 and ultimately removed by the Coast Guard in 1980, after which it was on display at the U.S. Coast Guard Academy Museum in New London, Conn. A few years ago it was placed in storage in Maryland and an offer was made to return it to its original home.
But that move comes with a cost, so to that end the museum and the Thacher Island Association have launched a fund-raising effort.
“First-order Fresnel lenses are extremely rare. There are only 39 in the country, three of which are in New England. The only other one in Massachusetts is at the Martha’s Vineyard Museum in Edgartown,” according to a press release. “Upon returning to Cape Ann, the lens will require conservation treatment estimated to take two weeks and cost approximately $75,000.”
The work will be done in one of the museum galleries where the public will be able to view the process.
Museum curator Martha Oaks said a lampist from Arizona, James Woodward, will be doing the work.
“There are just a few who are qualified to do the work, and he is among those approved by the Coast Guard to work on the lens,” she said. “We are all very excited about this.”
The museum already has a smaller Fresnel lens but of a much lesser order.
Oaks said an estimated $40,000 has been pledged so far.
“We hope to construct a room for it to make it visible from the outside as well from the back side of the museum in the maritime wing,” she said.
Paul St. Germain, president of the Thacher Island Association, said the Cape Ann Museum and his group support this project because not only will it preserve a historically-significant artifact, but it celebrates Cape Ann’s maritime heritage.
For more information or to make a contribution, contact Robert Bibelhauser at the museum at 978-283-0455 x15.
Gail McCarthy can be reached at 978-283-7000 x3445, or firstname.lastname@example.org.