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The Fresnel Lens. In 1822 the Fresnel lens was invented. An unlimited number of flashing combinations, could be produced. Ships found the lights to be brighter and they could see the lights at greater distances. The Fresnel lens is made of 100’s of pieces of specially cut glass.
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In 1822 the Fresnel lens was invented. • An unlimited number of flashing combinations, could be produced. • Ships found the lights to be brighter and they could see the lights at greater distances
The Fresnel lens is made of 100’s of pieces of specially cut glass. • It surrounds the lamp bulb, which concentrates the light downward.
Fixed Lens Shows a steady light all around the horizon Revolving Lens Produces a flash or characteristic. The number of flashes per minute depends on the number of flash panels and the speed at which the optic (lens) revolves. Two types of lenses
Because of the special design, and because it is made of glass, the lens intensifies the glow from the lamp. • The lens takes the rays of light and bends them into a single beam of light, which shines out in a specific direction.
Sites Noted http://www.uscg.mil/hq/g-cp/history/weblighthouses/lighthouse_curriculum.html http://www.outer-banks.com/lighthouses.asp