page_title: History of lighthouses
section_title: Lighting improvements
hierarchical_section_title: History of lighthouses / Modern lighthouses / Lighting improvements
caption_attribution_description: English: Print shows a lamp with glass chimney and circular, hollow wick designed by Ami Argand in 1784 that increased the amount of illumination. Illustration from Louis Figuier, Les Merveilles de la science, 1867-1869.
context_page_description: The history of lighthouses refers to the development of the use of towers, buildings, or other types of structure, as an aid to navigation for maritime pilots at sea or on inland waterways.
context_section_description: The source of illumination had generally been wood pyres or burning coal but this was expensive, some lighthouses consuming 400 tons of coal a year. Candles or oil lamps backed by concave mirrors were used, often in large banks. The French conducted a series of tests between 1783 and 1788 with varying results. Smeaton's Eddystone lighthouse used 24 candles until 1810.
  The Argand lamp, invented in 1782 by the Swiss scientist, Aimé Argand, revolutionized lighthouse illumination with its steady smokeless flame. The Argand lamp had a sleeve-shaped candle wick mounted so that air could pass both through the center of the wick and also around the outside of the wick before being drawn into cylindrical chimney. This steadied the flame and improved the flow of air. Early models used ground glass which was sometimes tinted around the wick. Later models used a mantle of thorium dioxide suspended over the flame, creating a bright, steady light. The Argand lamp used whale oil, colza, olive oil or other vegetable oil as fuel which was supplied by a gravity feed from a reservoir mounted above the burner. The lamp was first produced by Matthew Boulton, in partnership with Argand, in 1784 and became the standard for lighthouses for over a century.
  John Richardson Wigham was the first to develop a system for gas illumination of lighthouses. He was given a grant by the Dublin Ballast Board in 1865 and he fitted his new gas 'crocus' burner at the Baily Lighthouse in Howth Head, giving an output 4 times more powerful than the equivalent oil lights. An improved 'composite' design, installed in the Baily light in 1868, was 13 times more powerful than the most brilliant light then known, according to the scientist John Tyndall, an advisor to the United Kingdom's lighthouse authority, Trinity House.
  In 1870, the light at Wicklow Head was fitted with Wigham's patent intermittent flashing mechanism, which timed the gas supply by means of clockwork. When this mechanism was combined with a revolving lens in Rockabill Lighthouse, the world's first lighthouse with a group-flashing characteristic was produced.
  The vaporized oil burner was invented in 1901 by Arthur Kitson, and improved by David Hood at Trinity House. The fuel was vaporized at high pressure and burned to heat the mantle, giving an output of over six times the luminosity of traditional oil lights.
  The use of gas as illuminant became widely available with the invention of the Dalén light by Swedish engineer, Gustaf Dalén. In 1906, Dalén became the chief engineer at the Gas Accumulator Company. Initially Dalén worked with acetylene, an extremely explosive hydrocarbon gas. Dalén invented Agamassan (Aga), a substrate used to absorb the gas allowing safe storage and hence commercial exploitation. Acetylene produced an ultra-bright white-light and immediately superseded the duller-flamed LPG as the fuel of choice in lighthouse illuminations. Dalén incorporated another invention into his light - the 'sun valve'. This device allowed the light to operate only at night, conserving fuel, and extending their service life to over a year.
  The AGA lighthouse equipment worked without any type of electric supply and was thus extremely reliable. To a rugged coastal area like Scandinavia, his mass-produced, robust, minimal maintenance lights were a significant boon to safety and livelihood. AGA Lighthouses covered the entire Panama Canal. The technology was the predominant form of light source in lighthouses from the 1900s through the 1960s, when electric lighting had become dominant.
  The first electrically illuminated lighthouse was the tower at Dungeness, Kent in 1862. It was powered by a large carbon arc lamp, although it was later converted back to oil, as the arc lamps were difficult to operate (needing twice the number of keepers) and were not as cost-effective as oil lamps. South Foreland Lighthouse was the first tower to successfully use an electric light in 1875. The lighthouse's carbon arc lamps were powered by a steam-driven magneto.
caption: Argand lamp with circular wick and glass chimney. (Illustration from Les Merveilles de la science [1867-1869] by Louis Figuier).
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