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Three and One-half Order Fresnel Lens
Montauk Point New York
Harbour Lights #650
Lighted
Most inventions are discovered quite by accident. So it shouldn’t come as too much of a surprise to learn that the Fresnel lens got its start from the observation of singed curtains!
Augustin Fresnel, a French inventor, was looking for a way to improve the intensity of man-made light for use in lighthouses. As he studied the distortion of sunlight passing through thick pieces of glass, he experimented on magnification and refraction. All with limited results and dead-ends.
One day, he noticed the singed curtains through the window of a home. In the center of their decorative cut glass lay a “bull’s eye” inset. A perfectly circular singe mark lay behind the bull’s eye. Bad for the homeowners
-- good for mariners!
He excitedly began experimenting with a bulls-eye design and got immediate results. Although 60% of the rays were lost around the edges in his first design, it didn’t take him long to learn that cutting up the bull’s eye and placing the pieces around the central section of glass would fix the problem. The errant rays were redirected, following a steady, horizontal course. On July 23, 1823, Fresnel installed his first lens!
The bulls-eye design is readily appreciated in the magnificent three and a half-order Fresnel Bivalve lens found in the Montauk Point Lighthouse. The
dual-faced optic was installed in 1903, after having been displayed at the Columbia Exposition in Chicago. The underlying lamp, fueled by incandescent oil vapor, featured a silk mantel.
The lens rotated and flashed its white light every five seconds, guiding mariners past the easternmost tip of Long Island. The historic optic is now on display in the Montauk Museum’s Oil Room.
Augustin Fresnel
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HL# |
Name |
MSRP |
Introduced |
Retired |
Edition |
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650 |
Three and One-half Fresnel |
$89 |
Jun 02 |
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5,000 |
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