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 However, by 1910 there were only 2055 electric lamps of all types in use - about 0.25% of all safety lamps. In 1911, an anonymous colliery owner, through the British government, offered a prize of £1000 () for the best lamp to specified requirements. There were 195 entries. It was won by a German engineer with the CEAG lamp, which was hand-held and delivered twice the illumination of oil lamps, with a battery life of 16 hours. Awards were made to 8 other lamps that met the judges' criteria. Clearly this stimulated development and over the next few years there