Rideal, Sir Eric Keightley (1890-1974), a British chemist, carried out research into surface chemistry. He also studied colloids (substances composed of small particles suspended in another substance), and the properties and effects of catalysts (substances that increase the speed of a chemical reaction without being consumed by the reaction). He devised a method of measuring the germicidal (germ-killing) powers of disinfectants. Rideal was born in London on April 11, 1890, and studied at Cambridge University and at Bonn, in Germany. He was knighted in 1951 and died on Sept. 25, 1974.