Newton’s Alchemy and His ‘Active Principle’ of Gravitation

Abstract

During his undergraduate years, probably about 1664, Newton accepted the Cartesian postulate of a dense aether, acting mechanically by impact, as the cause of terrestrial gravitation.1 Manuscripts written during the next twenty years reflect his continuous commitment to some form of mechanical aether as the principle of gravitation, but in those papers Newton sometimes associated the mechanical gravitational aether with the quasi-spiritual “active principle” of alchemy that was responsible for certain non-mechanical natural processes.