History of chemistry iodine first, but both scientists acknowledged Courtois as the first to isolate the element. In 1815, Humphry Davy invented the Davy lamp, which allowed miners within coal mines to work safely in the presence of flammable gases. There had been many mining explosions caused by firedamp or methane often ignited by open flames of the lamps then used by miners. Davy conceived of using an iron gauze to enclose a lamp's flame, and so prevent the methane burning inside the lamp from passing out to the general atmosphere. Although the idea of the safety lamp had already been demonstrated by
Moderator lamp Moderator lamp The moderator lamp is a type of 19th century oil lamp. It displaced the more complex Carcel lamp which used a clockwork pump. Its mechanism was simpler and required less maintenance or repair. The moderator lamp was invented in 1837 by Charles-Louis-Félix Franchot (1809-1881) . Like the Carcel lamp the oil reservoir was below the burner and it allowed 360 degree illumination. Earlier oil lamps such as the Argand had a reservoir above the burner which made them top heavy and obscured some of the light. The reliability of the mechanism led to them being adopted in lighthouses.