A deck prism, also known as a dead light or deck light, is a piece of molded glass that reflects light into the lower reaches of a ship. It was used on wooden ships before the availability of electricity as a safer alternative for lighting than kerosene and oil lamps or candles.26 Jan 2022
What are deck prisms made of?
One of these is the deck prism (also known as a deck light). This particular deck prism is said to be from the whaleship Charles W. Morgan. A hexagonal cone, it is made from bluish-green-clear glass, and dates from the 1840s, the earliest known date for this design.
When were deck prisms used?
1840
What is a glass deck prism?
A deck light or deck prism is a prismatic glass set into a ship's deck, to let natural light below. They are especially useful when an open flame would be hazardous, such as with a cargo of coal or gunpowder.
What does a deck prism do?
For centuries, sailing ships used deck prisms to provide a safe source of natural sunlight to illuminate areas below decks. 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.
Who invented the deck prism?
In 1818, Grant Preston of Middlesex, Brazier (England) was granted a patent for his "IMPROVEMENT IN THE DECK GLASS RIM AND SAFETY GRATE", No. 4,222.