File:Lighthouse lantern room with Fresnel lens.png
Summary
Cutaway drawing of a <a href="https://en.wikipedia.org/wiki/lighthouse" class="extiw" title="wikipedia:lighthouse">lighthouse</a> lantern room from mid 1800s showing the Fresnel lens. Source says this was a lens of the 'largest size', made by M. Souter and exhibited at the Paris Universal Exposition in 1855. The cylindrical lens with 8 faces stood 10 feet high. A clockwork mechanism (M), driven by weight (P), slowly turns the entire lamp-lens assembly (A,B) on six rollers. This system, invented by Augustin-Jean Fresnel, scans the 8 beams from the lens around the whole horizon. The resulting regularly flashing light seen by mariners served to distinguish the lighthouse from stars or shore lights. Alterations: removed caption.
Licensing
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File history
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| Date/Time | Thumbnail | Dimensions | User | Comment | |
|---|---|---|---|---|---|
| current | 19:30, 6 January 2017 | | 642 × 892 (150 KB) | 127.0.0.1 (talk) | Cutaway drawing of a <a href="https://en.wikipedia.org/wiki/lighthouse" class="extiw" title="wikipedia:lighthouse">lighthouse</a> lantern room from mid 1800s showing the Fresnel lens. Source says this was a lens of the 'largest size', made by M. Souter and exhibited at the Paris Universal Exposition in 1855. The cylindrical lens with 8 faces stood 10 feet high. A clockwork mechanism (M), driven by weight (P), slowly turns the entire lamp-lens assembly (A,B) on six rollers. This system, invented by Augustin-Jean Fresnel, scans the 8 beams from the lens around the whole horizon. The resulting regularly flashing light seen by mariners served to distinguish the lighthouse from stars or shore lights. Alterations: removed caption. |
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