Saint Augustine Fresnel Lens History
Fresnel (fruh-nel) Background
Augustin-Jean Fresnel, a French physicist, was recruited by the French Government as the French
Commissioner of Lighthouses, in 1819 to develop a lens for Lighthouses. An early lighthouse
system, reflector panels behind oil-lamps were inefficient. They focused as little as 3% of total
light emitted into a useful signal. The only way to increase the strength of the signal/ light was to
increase the flame height.
Fresnel solved that problem. He began to experiment with multiple part lenses that refracted light
into horizontal planes. In 1922, he developed a multipart lens for Lighthouses that made him
world famous. Not only could would the Fresnel lens reflect and refract light it captured as much
as 80% of the light from the light source. This could be seen 20 miles out to sea, and the lens could
be shipped and reassembled easily in a tight lantern room. It could also be re-configured with
special prisms and bulls-eye panels into distinct light signatures. European lighthouses were the
first to adopt Fresnel lenses.
The great majority of US Lighthouse lenses in the 19th century used in the United States came from
France in the vicinity near Paris. Francois Soleil Sr. was the first to build these lenses. Ultimately there
would be a variety of French companies responsible for the manufacture of almost all of the original
Fresnel lenses. Eventually a British Company Chance Brothers would join the group.
These French companies were:
Letourneau & Co, which took over from Francois Soleil Jr.
Henry-Lepaute
Lemonier
Sauter, who took over from Letourneau, and later merged with Lemonier.
Barbier & Fenestre.
Barbier, Benard & Turenne, who took over from Barbier & Fenestre.
Grisman, who took over from Barbier, Benard & Turenne.
Fresnel lenses were divided into eleven orders (sizes) by the distance of from the light source to
the focal plane. A first order was 8.5 feet tall and about 36 inches from flame to focal point. A
sixth order lens by comparison was only about 5.9 inches from lamp to the focal plane.
Saint Augustine’s Lens
The First Order Fresnel Lens at the Saint Augustine Lighthouse is 9 feet tall. It was hand-blown in
Paris, France by Sauter & Lemonnier specifically for the Saint Augustine Lighthouse in 1874.
On Feb 28th, 1889, The Saint Augustine Weekly News described the lens in the following
manner.
“The lamp was a brass cylinder of 10 gallons capacity. Inside it has a heavy weight which
governs the flow of oil to the burner. The burner has five wicks in concentric circles. A chimney
leads to the roof. It has a damper which regulates the flame. The globe is a huge case of glass
which revolves around the lamp every 9 minutes. It makes a flash every three minutes when a big
bulls-eye lines up between the lamp and the human eye. The cage weighs two tons. It revolves
around a clock work. The machine is in the glass case directly below the lantern.”
1909, an incandescent oil-vapor lamp (kerosene) was installed for the light. This lamp used a
single mantle and 2 gallons of kerosene a night (according to head keeper CD Daniels in 1936).
In 1936, the lighthouse became electrified. In order to save money, the Bureau of Lighthouses
reduced the number of keepers here from 3 to 2. The distinctive night signature was also changed
from one fixed white flash every 3 minutes, to one fixed white flash every 30 seconds. This
signature has stayed in place until today.
The St. Augustine Lighthouse was the last lighthouse in Florida to be electrified. While it is
unclear exactly why this happened, letters in our archives indicate that the government had a
problem deciding what type of light to use. Evidently, our lens is rather unique and the experts
debated for quite a while before deciding on the best way to electrify it.
In a letter from 1934, the Superintendent of Lighthouses stated: “The lens at St. Augustine
Lighthouse is of unique design. It is possible that there is not another one like it in the
entire Lighthouse Service.” Also, the Bureau was testing different types of lamps and model they
hoped to use in St. Augustine proved not to be as effective as they had hoped.
In 1986, a vandals 30.06 bullet damaged the lens at Saint Augustine, piercing 19 of the original
prisms and making a hole in an original, bulls-eye panel. In 1991 the USCG shut down the lens to
avoid further damage and replaced it with an airport beacon. The Junior Service League of Saint
Augustine began to raise the funds to repair the damaged lens before the USCG could permanently
remove and replace it.
Working with Dan Spinella, of Disney Corp., Joseph Cocking and Nicholas Johnston of the United
States Coast Guard the museum’s parent organization, reconstructed and repaired historic optic.
This was the first historic lens restoration in the United States. A lens workshop was held to teach
others about lens restoration and many lenses across the United States have been saved because
of the Saint Augustine community and the JSL.
Today only 16 original First Order Fresnel Lenses remain inside Lighthouse towers and in use in
the United States. The Saint Augustine Lighthouse and Museum, Inc owns and operates this
historic optic. It was decommissioned and given to the museum by the United States Coast Guard
and the National Park Service through the General Services Administration in July of 2002.