Which fuels and light sources were used in early lighthouses?

Early lighthouses relied on a variety of fuels and light sources to aid maritime navigation, evolving significantly over time:

• Open Fires: The earliest lighthouses, including those of antiquity and the medieval period, primarily used wood fires or torches burned in the open, sometimes protected by a roof.12
• Coal: Starting around 1550, coal became a favored fuel in northwestern Europe because it was more compact and longer-burning than wood. However, coal fires and early wood fires produced significant smoke, which blackened lantern panes and obscured the light.3
• Candles and Oil: Candles and oil lamps were also used in lanterns with glass or horn panes as early as the 1st century CE.1
• Argand Lamps: In 1782, the invention of the Argand burner revolutionized lighthouse illumination by providing a steady, smokeless flame using a circular wick and glass chimney. These lamps initially burned fish oil, later transitioned to vegetable oil, and by 1860, used mineral oil.4
• Gas and Vaporized Oil: Around the turn of the 20th century, acetylene gas and vaporized kerosene burners were introduced, offering more powerful and controllable light sources that enabled the development of automatic, unattended lighthouses.45