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 Mueseler, Landau and Yates lamps below. Such a lamp was known as a "protector" lamp, a term picked up and used as a company name. Only on the return to the bank could the lamp man open the lamp for refilling and service. Various different locking mechanisms were developed; miners tended to be ingenious in finding ways of circumventing them. A number of additional lamps were supposed to accompany each gang of men, but restricting the number was an obvious economy for the pit owners. The light given out by these lamps was poor (particularly the Davy where it