File:Lighthouse lantern room with Fresnel lens.png
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Size of this preview: 431 × 599 pixels. Other resolutions: 173 × 240 pixels | 345 × 480 pixels | 642 × 892 pixels.
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Summary
| Description |
English: Cutaway drawing of a lighthouse 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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| Source | Downloaded from Adolphe Ganot (1872) Natural Philosophy for General Readers and Young Persons (translated with permission from Ganot's Cours Élémentaire de Physique by Edmund Atkinson), D. Appleton & Co., New York, p.329, fig.258 on Google Books | ||||||||||||||||
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Licensing
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The author died in 1887, so this work is in the public domain in its country of origin and other countries and areas where the copyright term is the author's life plus 100 years or fewer. This work is in the public domain in the United States because it was published (or registered with the U.S. Copyright Office) before January 1, 1930. |
| This file has been identified as being free of known restrictions under copyright law, including all related and neighboring rights. | |
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| Date/Time | Thumbnail | Dimensions | User | Comment | |
|---|---|---|---|---|---|
| current | 13:58, 17 December 2007 | | 642 × 892 (150 KB) | wikimediacommons>Chetvorno | {{Information |Description=Cutaway drawing of a lighthouse lantern room. Source says this was a lens of the 'largest size' made by M. Souter and exhibited at the Paris International Exposition in 1855. |Source=Downloaded from [http://books.google.com/boo |
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