 Imagine a time when we believed in phlogiston, a mysterious substance thought to explain combustion and rusting. According to this theory, burning released phlogiston, leaving behind deflogisticated residue. But then came Lavoisier, who revolutionized chemistry with his conservation of mass principle. His experiments shattered the phlogiston theory, paving the way for a modern understanding of chemical reactions and the vital role of oxygen. Science always evolving, always fascinating.