The valve formed part of the Dalen Light which was used in lighthouses from the 1900s through to the 1960s by which time electric lighting came to dominate. A Dalen Light was the predominant form of light source in lighthouses from the 1900s through to the 1960s by which time electric lighting would come to dominate. ... The Peggys Point lighthouse in Nova Scotia, Canada An aid for navigation and pilotage at sea, a lighthouse is a tower building or framework sending out light from a system of lamps and lenses or, in older times, from a fire. ...
The valve is controlled by four metal rods enclosed in a glass tube. One rod is blackened, while the others are highly polished. As daylight made the rocks visable, the heat of the sun allowed the expanding dark rod to cut the gas supply.
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