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 Acetylene produced an ultra-bright white-light and immediately superseded the duller-flamed LPG as the fuel of choice in lighthouse illuminations.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. Optics With the development of the steady illumination of the Argand lamp, the application of optical lenses to increase and focus the light intensity became