Safety lamp could create a sufficient updraft that firedamp would not penetrate down the chimney. Further observations of the speed of flame fronts in fissures and passageways led him to design a lamp with fine tubes admitting the air. Sir Humphry Davy was asked to consider the problems of a safety lamp following the Felling explosion. Previous experimenters had used coal gas (chiefly carbon monoxide) incorrectly, believing it to be the same as firedamp. Davy however performed his experiments with samples of firedamp collected from pits. As an experimental chemist, he was familiar with flames not passing through gauze; his experiments enabled
Safety lamp was surrounded by gauze so that in the event of a glass breakage the Geordie became a Davy. If the current of air forced in through the tubes (later holes and gallery) by the lamp's situation was too strong, the flame grew, and the lamp could get red-hot. The lamp becomes unsafe in a current of from 8 to 12 feet per second, about twice the limit of the Davy's safe operating conditions. However, this variation in the flame was not entirely bad. The intensity of the flame, air currents being equal, gives an indication of firedamp levels, so it