American inventor Charles Goodyear tried for five years to find a way to make rubber a useful product. He wanted rubber that would not melt in the heat or become brittle and stiff in the cold. He applied various treatments to the substance, but none worked. One winter night in 1839, Goodyear accidentally dropped a piece of rubber sprinkled with sulfur onto a red-hot stove. To his astonishment, instead of melting, the rubber flattened out into a small disk. Lifting it from the stove, he found it was still flexible and strong. He then hung the disk on his doorpost overnight in the winter cold. The next morning, the disk still had its rubber-like qualities. Goodyear had accidentally invented vulcanization—the process of heating rubber treated with sulfur to give the rubber elasticity, hardness and strength.