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
Davy lamp supporters refused to accept their findings, and would not see how an uneducated man such as Stephenson could come up with the solution he had: Stephenson himself freely admitted that he had arrived at a practical solution on the basis of an erroneous theory. In 1833 a House of Commons committee found that Stephenson had equal claim to having invented the safety lamp. Davy went to his grave believing that Stephenson had stolen his idea. The Stephenson lamp was used almost exclusively in North East England, whereas the Davy lamp was used everywhere else. The experience gave Stephenson a lifelong