Vulcanization

Charles Goodyear's rubber on the stove, Woburn, Massachusetts, 1839 Goodyear had already spent years adding things to rubber, sulfur included, trying to make it less sticky and less sensitive to heat and cold. Then a sample mixed with sulfur landed on a hot stove and came out tough instead of soft. Versions of the moment vary, from a dropped lump to a flung sample, but the outcome does not: heat plus sulfur was the missing step. It still took him until 1844 to secure a patent for the process. Tires, hoses, seals and shoe soles all depend on it, yet Goodyear died in 1860 owing about $200,000, having spent his last years fighting infringers in court.