A chemist designed a flame that couldn't ignite the gas trying to kill miners

Coal mines in the early 1800s regularly exploded when open candle flames met pockets of flammable 'firedamp' gas underground. In 1815, Humphry Davy worked out that enclosing a flame inside fine wire gauze let light and air through but stopped the flame from reaching gas outside the mesh, since the metal conducted heat away too fast for a flame to pass through it. He refused to patent the Davy lamp, wanting it freely available to save miners' lives.

— Humphry Davy, On the Fire-Damp of Coal Mines, and on Methods of Lighting the Mines So As to Prevent Its Explosion — Philosophical Transactions of the Royal Society, 1816