9th December 1921: Lead identified as a fuel additive to reduce engine knocking in automobiles

Thomas Midgeley Jr. discovered that adding tetraethyl lead to gasoline reduced knocking in automobile engines.

20th April 1902: Marie and Pierre Curie prove the existence of radium

Marie and Pierre Curie proved the existence of the new element radium when they chemically isolated one-tenth of a gram of pure radium chloride.

16th February 1937: Organic chemist Wallace Carothers is awarded a patent for nylon

The DuPont company’s organic chemist Wallace Carothers received a patent for linear condensation polymers, the basis of the material better known as nylon.