Lighthouses

1
Lighthouses
By Peter D Aberdeen High School, 1999
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Lighthouse History

• First lighthouses
  -found around Mediterranean Sea -consisted of
  fires on top of coastal hills
• First traditional lighthouse structure -Pharos
  light of Alexandria constructed around 280
  B.C. 280 feet tall -reflectors contained
  wood fire -could be seen for 35 miles

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Lighthouse History- 2

• Ancient Lighthouses -Portus, Italy 46 A.D.
• -Boulongne, France
• -Dover, England
• -Genoa, Italy 1139
• -Leghorn 1304
• First in U.S.
• -Boston Light near Boston Harbor, 1716

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Lighthouse History - 3

• U.S. lights maintained and upkept by U.S. Coast
  Guard since July 1, 1939.
• Worldwide, more than 30,000 lights today
• First lightship stationed in Thames estuary in
  1732

5
Fresnel Lens

• First constructed in 1822 by French physicist A.
  Fresnel
• Uses concentric rings of glass prisms to bend and
  focus light into a narrow beam
• Often as tall as twelve feet

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Concord Point Lighthouse
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Concord Point Light - 2

• Built in 1827 at the mouth of the Susquehanna
  River in Havre De Grace
• 36 foot tower, originally built with tin
  reflector, upgraded to fresnel lens in 1854
• Decommissioned in 1975

Link to information on Concord Point Lighthouse
and other lighthouses