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
Döbereiner's lamp said that in 1820s over a million of the "tinderboxes" were sold. Examples of the lighter are exhibited in the Deutsches Museum and in the old pharmacy at Heidelberg Castle. Döbereiner's lamp Döbereiner's lamp, also called a "tinderbox" ("Feuerzeug"), is a lighter invented in 1823 by the German chemist Johann Wolfgang Döbereiner; the lighter is based on the Fürstenberger lighter and was in production until ca. 1880. In the jar, similar to the Kipp's apparatus, zinc metal reacts with dilute sulfuric acid to produce hydrogen gas. When a valve is opened, a jet of hydrogen is released onto a platinum