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Antique Glass Deck Prism

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AmatoorPikr's loves364 of 1741Two Identical Architectural Landscape Paintings !/16" x 20" and 17" x 21"/Signed Hansson (Nils Edvin??)/Circa 1947Friday's Estate Sale Finds
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    Posted 3 years ago

    (47 items)

    I've had this ship's prism for quite some time, but honestly cannot remember the family member it came from. The smooth, hexagonal face measures 4 1/2" between opposing vertices, and 4 1/8" between opposing sides. The overall height to the tip is 4 1/2". It is quite heavy for it's size, and I'm not sure exactly how old this particular prism is.

    What I found out was that for centuries, sailing ships used deck prisms to provide a safe source of natural sunlight to illuminate areas below decks. Before electricity, light below a vessel's deck was provided by candles, oil and kerosene lamps—all dangerous aboard a wooden ship. The deck prism was a clever solution: laid flush into the deck, the glass prism refracted and dispersed natural light into the space below from a small deck opening without weakening the planks or becoming a fire hazard.

    In normal usage, the prism hangs below the overhead and disperses the light sideways; the top is flat and installed flush with the deck, becoming part of the deck. A plain flat glass window would just form a single bright spot below—not very useful for general illumination—hence the prismatic shape.


    1. racer4four racer4four, 3 years ago
    2. AmatoorPikr, 3 years ago
    3. PostCardCollector PostCardCollector, 3 years ago
      That is helpful information , I can picture it n my mind but not how much light could actually emanate from it. Maybe some shown at some time were in a painting, picture or a book , or a movie-- Is there is an illustration depicting an example of it? What about the color; would there be a purpose for green? How old do you think it is. Do you display it?
    4. VintageMisc VintageMisc, 3 years ago
      I can only offer the following link to the Charles W. Morgan, the last surviving wooden whaler in the world that had deck prisms:

      Unfortunately, I'm leaving tomorrow for a month.

      I do display it in a manner, along with other items on a shelf.
    5. TallCakes TallCakes, 3 years ago
      this prism looks just like one I purchased new at Restoration Hardware around 1998; it is the same size and has same textured finish.
    6. VintageMisc VintageMisc, 3 years ago
      I received it in 1989, and just put it on a shelf with the other old items from family. As to it's age, I have not clue. But it is definitely older than 1998.
    7. PostCardCollector PostCardCollector, 3 years ago
      OMG! YOUR LINK is wonderful... Really shows this prism in action. God! I wish I was on that ship!!
    8. Goodoody Goodoody, 3 years ago
      Awesome piece.

      I've always been reluctant to buy these for fear of repops. I've always wondered if there was a sure fire way to tell the difference between repops and genuine antique prisms.

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