John Dalton
John Dalton (1766-1844), British chemist. His early work was in the fields of meteorology and colour blindness. In 1801 he published the results of his re-searches into gases, including the law of partial pressures. This law states that the total pressure exerted by a mixture of gases is equal to the sum of the pressures of the component gases. Dalton also developed the atomic theory of matter and attempted to calculate the atomic weights of elements.