The Phlogiston theory

The Phlogiston theory, developed in the 17th century, proposed that a substance called "phlogiston" was released during combustion. According to this theory, flammable materials contained phlogiston, which was responsible for their ability to burn. When something burned, it supposedly released phlogiston into the air. This idea was widely accepted until the late 18th century when Antoine Lavoisier demonstrated that combustion involves the chemical reaction with oxygen, leading to the modern understanding of oxidation. The Phlogiston theory was ultimately discarded, but it played a crucial role in the evolution of chemical science.