born Nov. 27, 1903, Oslo, Nor.
died Oct. 5, 1976, Coral Gables, Fla., U.S.
Norwegian-born U.S. chemist.
He immigrated to the U.S. and taught principally at Yale University. His development of a general theory of irreversible chemical processes, described as the "fourth law of thermodynamics ," gained him a 1968 Nobel Prize. He also applied the laws of thermodynamics to systems not in equilibrium . His explanation of the movement of ion s in solution as related to turbulence and fluid density had a major effect on the development of physical chemistry .