A clever solution for the lighting problem was the deck prism. Laid flush into the deck, small conical prisms drew light down below decks, without weakening the deck planks. Mosser Glass has produced replica deck prisms for Mystic Seaport in Mystic, Connecticut for years. The deck prisms are an exact reproduction of Mystic Seaport's ...remaining original CHARLES W. MORGAN deck prism. We have produced a limited addition color Gem Green that will only be avilable in our retail store!