Humphry Davy and the Murder Lamp

The miners’ safety lamp is an icon of the Industrial Revolution every bit as powerful as Stephenson’s Rocket or the Iron Bridge at Coalbrookdale. It’s a beautiful thing: polished brass and glass cylinder, magnetic lock, and the little naphthalene flame lit by a flint and wheel. You can still buy one, because even today every pit deputy must carry one, despite the universal use of electricity for lighting collieries. The reason is that the safety lamp is first and foremost a methane detector; the colour and shape of the flame indicates how much methane or ‘fire-damp’ is present in the atmosphere. That some concentrations of firedamp are more deadly than others has been known since long before 1816 when Sir Humphry Davy developed the lamp that bears his name.