For more than a century, some of the best chemists in the world accepted that a substance leaving a metal during burning could make the metal heavier. This episode traces the rise and fall of phlogiston, from Johann Joachim Becher's oily earth in 1667 and Georg Ernst Stahl's 1703 rebranding to Antoine Lavoisier's sealed-jar experiments.

Along the way we look at how the theory unified combustion, metallurgy, plant growth, and breathing; how the weight gain seen in calcination forced defenders to propose negative mass or buoyancy; how Daniel Rutherford and Joseph Priestley named nitrogen and oxygen through the phlogiston lens; and how Elizabeth Fulhame's water experiments, Giovanni Antonio Giobert's 1792 prize paper, and Pierre Macquer's desperate patches marked the end.

• Why the four-element model of Empedocles and Aristotle could  ...