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
Safety lamp the lower brass ring supporting the glass. The lamp is in part a development of the Geordie. Air enters into a ring near the base which is protected by gauze or perforated plate. The air passes down the side of the lamp passing through a series of gauze covered holes and enters the base through another yet another series of gauze covered holes. Any attempt to unscrew the base causes the lever (shown at "f" in the illustration) to extinguish the flame. The gauze covered holes and passageways restrict the flow to that required for combustion, so if any part