From Tragedy to Beauty: Thacher Island and the Fresnel Lens

As an occasional “lighthouse keeper” on Thacher Island, CAM Docent, Suellen Wedmore shares her enthusiasm for both this beautiful island of 50 acres, the site of the only operating twin lighthouses in America, and for the stunning Fresnel lens, “the invention that saved a million ships,” now beautifully housed in the Cape Ann Museum:

This image has an empty alt attribute; its file name is image-3.jpeg
Welcome to a little piece of Rockport’s Thacher Island at 27 Pleasant Street at the Cape Ann Museum in the heart of Gloucester!  
Shown here: Fresnel Lens originally designed by Augustine Jean Fresnel. In 1819, the French government commissioned 34 year old Fresnel to develop an improved lighting system for lighthouses. 

Those of you who have visited Thacher Island on a summer day will attest to the island’s beauty. Despite their beauty, the 124-foot light towers weren’t erected for our admiration, but rather out of a community’s need for protection from the dangers of an unpredictable sea. Understanding the history of the island will help us appreciate the splendor of its lights and its magnificent lens.

What is now called Thacher Island was noted in the writings of Samuel de Champlain and John Smith, who both circled it in the early 17th century. The island became a part of Cape Ann’s geographical and literary history after a devastating shipwreck in 1635.

In August of that year, recent emigrants from England, Anthony Thacher, his wife and four children, his cousin Reverend Avery and his wife and six children, boarded a pinnace (an early schooner), [or a bark], the Watch and Wait, in Ipswich to establish a church in Marblehead, Massachusetts.

Tragically, the “Great Colonial Hurricane,” one of the worst storms remembered by those who experienced it, blew in from the south. The Watch and Wait, seeking the calm of Sandy Bay Harbor, lost its mast and the anchor broke loose, causing the ship to crash against a ledge north of Straitsmouth Island.

Thacher later wrote of the ordeal, relating how he was helplessly tossed by the sea until he was able to creep onto dry land. When the storm subsided, only he and his wife, out of the 23 passengers and crew, had survived.

The General Court, sympathetic to Thacher’s loss, gifted him ownership of the island. Though Anthony never returned to what he labeled “Thacher’s Woe,” the island remained in the family for 80 years.

In this era of 24-hour weather forecasts and global positioning devices, it is difficult for us to appreciate the dangers presented to our ancestors by the sea’s storms and unseen ledges. Patriot John Hancock, with shipping interests in the area, was well aware of the dangers. He petitioned the General Court to build lighthouses on Thacher Island, the cost to be reimbursed by tolls to ship owners.

In response, two 45-foot rubble and wood towers were lighted in 1771, enabling mariners to discriminate Cape Ann Light Station from Portsmouth Light to the north and Boston Light to the south. They were the only towers at the time to mark a danger to mariners (the Londoner Ledge, southeast of Thacher Island) rather than the safety of a harbor. The towers were erected on a perfect north/south axis, which enabled fishermen to line up the lights to determine true north.

Unfortunately, only 18 months later, the keeper, accused of being a “Tory,” was removed. It wasn’t until 15 years after the Declaration of Independence was signed that the government took over maintenance of the lighthouses.

During the following years, despite experimentation with fuels and types of lamps, ships continued to founder off Cape Ann. It was time to talk of replacing the two towers with taller ones of sturdier construction.

In 1858, Congress appropriated funds for two new towers, these to be much taller, at 124 feet and of granite construction. They were lighted for the first time in October, 1861.

Twin Lights, Thatcher’s Island from Brier Neck. Photographer: John Heywood, ca. 1864-66. Benham Collection of the Cape Ann Museum Library & Archives.

In 1861, the towers were rebuilt with granite to their new height of 124 feet and a first order Fresnel lens was installed. The light of the whale oil lamps could now be seen as far away as 22 miles at sea. 

It was soon after this that Cape Ann’s local heroine, Maria Bray’s courage and stamina were tested.  

On December 21, 1864, her husband and keeper of the light, Alexander Bray, a Civil War veteran who had recently become principal keeper, rowed to shore to seek medical help for an ill assistant. A heavy snowstorm blew in that afternoon, making it impossible for him to return to the island.

According to most versions of the story, Maria and her 14-year-old nephew, Sidney Haskell, braved the high winds and heavy snow, climbing the 156 steps of both towers every three hours to keep the lanterns burning. On December 24th, the wind quieted and Alexander made a run for the island, where he found an unharmed Maria and her nephew asleep.

One of Maria Bray’s tasks as a keeper’s wife would have been to help polish the beautiful and imposing Fresnel lens, then at the top of the tower.

What would it be like to undertake such a task? 

Polishing the Fresnel Lens  – a poem by Suellen.

I dress in layers  
against the wind,  
struggle toward the tower,  

how many were lost  
before Monsieur Fresnel  
sharpened light  
& tilted it  
toward the horizon?  

pull open the heavy iron door  
to begin the spiral ascent,  
156 stairs from ground to sky,  
step into the lantern room,  

a glass bubble floating  
above the blue-green world;  

the metal floor rings  
as a boot heel  
strikes a rainbow, 

a prism splinters light  
into indigo, red, green & gold,  

pluck a chamois  
from the worn brass box,  
step toward the lens  
on its iron pedestal,  

a shimmering glass beehive  
taller than a man,  
mélange of diamonds & star,  

swirl away night’s soot.  
How does the lens work?  
visitors ask.  

Imagine slicing a magnifying glass  

into a hundred concentric rings,  
each one thinner than the last,  
so that it splinters,  
refocuses the flame,  

or imagine feathered light  
squeezed by great hands  
into a single beam  
& hurtled toward the horizon. 

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s