After physics, Isaac Newton took up alchemy until he published the Principia Mathematica. Alchemy was not a minor curiosity for Newton: from the 1660s onward, he read extensively, copied laboratory recipes, and performed experiments involving metals, acids, furnaces, and distillation.
To Newton, alchemy was part of a serious attempt to understand matter and the hidden forces of nature. Seventeenth-century boundaries between chemistry, physics, medicine, and alchemy were fluid, so his alchemical work was not necessarily viewed by him as opposed to “real” science. He investigated ideas such as metallic transmutation and the philosopher’s stone, while also searching ancient texts for clues about nature’s structure.
Newton’s alchemical studies overlapped with his work in optics, mathematics, theology, and biblical chronology. That overlap is a common source of confusion: alchemy was his best-known secondary scientific pursuit, but it was not the only subject he studied during the years before the Principia. His great physics treatise, Philosophiæ Naturalis Principia Mathematica, was published in 1687 and established his laws of motion and universal gravitation.