Barnegat Light, a town on the coast of New Jersey, had a reputation in the 1800s. It
was the graveyard of the Atlantic.
It had fast currents, sandbars that shifted, and shoals, hidden ridges that wrecked ships,
but this narrow passage was crucial for tons of traffic from Europe.
The result was wreck, after wreck, after wreck, after wreck.
The lighthouse was intended to guide ships away from land. It didn't, and a lot of lighthouses
around the world had the same problem. The problem at Barnegat was the light inside that
lighthouse. It just wasn't strong enough, and the solution was an invention that fixed
lighthouses from France to Florida, an international upgrade that's still in use today and is used
in things like this. The lighthouse wasn't enough to save ships.
They needed the right lens. "I volunteered at the St. Augustine Lighthouse
here in Florida. It was in 1992, so it was a while back. And I saw the different lens
and it was just beautiful, and I stood inside of this, surrounded by all these glass prisms,
and I was just intrigued by it and I wanted to know how it worked. My name is Dan Spinella
with Artworks Florida Classic Fresnel Lens, and I'm a lens preservationist and designer.
I build historic reproductions of classic Fresnel lenses and also build the prisms and
lenses to help restore the original classic Fresnel lenses."
This is a Fresnel lens, the breakthrough that made lighthouses work like lighthouses should
work.
Light from a lamp is diffuse, too weak for a ship to see it from far away. A Fresnel
lens fixes that. It takes that light and, using prisms, redirects and magnifies it in
one unified direction. See how this light in this light both go the same way? A candle
becomes a spotlight. This is a Fresnel lighthouse with bullseye panels in the middle, and those
look like lights a lot of people use in lighthouses everywhere.
"You know, I have a light Fresnel that I attached to my my little spot light up here. It should
be pretty much the same thing, right?"
"Yes, it is. It is identical in design. And that's what's amazing about it, is something
that was designed in 1819 is still being used today."
It normally attaches to a light to make a spotlight, but it is a Fresnel. When I light
a candle, it takes that light and focuses it into a spotlight. And so the light gets
more intense, the brighter I make it or, in this case, the closer I hold it to the center
of the lens. The same thing happens when I use my phone. The Fresnel captures all of
that light and focuses and magnifies it. These lenses weren't just an improvement. They created
a whole system that saved lives.
Augustin-Jean Fresnel, an engineer and physicist, was part of a French lighthouse commission
to improve lighthouses. Developed through the 1820s, Fresnel's lens proved better than
existing lights, including the ones at Barnegat.
"Tens of thousands of wrecks are scattered throughout the mooring and shoals and up and
down that area of New Jersey. There were a lot of flaws with the lighthouse there, Lewis
lights. The Lewis lamp was successful and so far it was better than nothing. However,
the technology was flawed. It was lacking."
Like many lamps at the time, a Lewis lamp used a reflector to catch light. It had a
small lens to project that light, but a lot of light escaped.
"It wasn't bright enough, so they weren't as efficient and the metal wasn't as efficient
because it absorbs a lot of the light. That's why the design of the Fresnel lens was so
much more efficient that it collected more of the light and directed at seaward the way
it's supposed to do."
In addition to strengthening and magnifying light, Fresnels flashing with rotation turned
them into a communication device.
"So it creates this flashing characteristic. Even though the lamp is continuously on. It
was a flame. You couldn't turn it off depending on how they designed the lens. It creates
different flashing characteristics.
So you knew where you were at, what location you were at before GPS.".
Colored panels or even colored flames could make lights more distinct. Some got huge.
A first order Fresnel was this big. More than 75 for are still up and running today in the
United States alone. Thanks to these lenses that rippled across the globe, lighthouses
cast light farther, communicate more information, and save lives.
The Lighthouse is a wonderfully strange 2019 movie in which a Fresnel is so hypnotic, Willem
Dafoe's character undresses and bathes in its light. The director called it the "cosmic
egg." With the production designer, Dan Spinella made the lens in the film.
"I had to work a lot of hours. I probably worked 14, 16 hour days for eight weeks straight,
seven days a week. I didn't take any breaks. I got it done just in time. Probably five
days before filming I was crating it up. I had to drive it up to Nova Scotia from Florida."
"It's sort of a weird showcase for your work because it's it's sort of the most flattering
possible look for your work. But in a really weird movie."
"It's definitely not a feel good Hallmark movie, that's for sure. I mean, I like the
fact that the focus was on the lens and I like the little sneak peek of the lens until
you got to the very end of the movie then actually actually saw it? It was almost a
star in the movie itself. They did a really good job getting everything historically accurate.
The very first lens that I worked on, the St. Augustine Lighthouse, when I started designing
that lens on the computer, I was just amazed at how the formulas were actually working.
And to think that they did that in the 1800s and they went to these formulas and the same
thing I was doing.".
Crashes still happened at Barnegat even after they added a fourth order Fresnel. The lighthouse
was small and the sea was dangerous. But in 1857, they built a new lighthouse, and it
was crucial that they have one thing in it.
"They got a Fresnel lens and not just any Fresnel — the biggest one that they built,
which was a first order lens. The Mariners were very grateful for because it did save
lives because, unlike a Lewis light, this would shine in at least 20 miles. They really
don't know how far it could shine because the curvature of the earth. That's how powerful
it is."
"What they did to rotate the lenses, they used a clockwork mechanism. They didn't have
electricity, they didn't have electric motors. They used a clockwork mechanism, which is
very similar to a grandfather clock. There's a weight that would drop down the center of
the lighthouse. And that weight was attached to a cable which was wrapped around a drum.
And that drum had a gear on the end of it. And that gear drove a series of gears inside
the clockwork mechanism. And that, determined by the ratio of the gears, determine the speed
at which the the lens would rotate, which engaged with a gear that was underneath the
bottom of the lens. The lens was on either chariot wheels, ball bearings, or in some
cases it was a mercury bath that allowed it to rotate. So that was built as a demonstration
for the Pensacola Lighthouse."