1) Alchemy refers to both an early protoscientific and an early philosophical discipline, both combining elements of chemistry, metallurgy, physics, medicine, astrology, semiotics, mysticism, spiritualism, and art. Alchemy has been practiced in Ancient Egypt, Persia, India, and China, in Classical Greece and Rome, in the Islamic empire, and then in Europe up to the nineteenth century — in a complex network of schools and philosophical systems spanning at least 2500 years.
Western alchemy has always been closely connected with Hermeticism, a philosophical and spiritual system that traces its roots to Hermes Trismegistus, a syncretic Egyptian-Greek deity and legendary alchemist. These two disciplines influenced the birth of Rosicrucianism, an important esoteric movement of the seventeenth century. In the course of the early modern period, as mainstream alchemy evolved into modern chemistry, its mystic and Hermetic aspects became the focus of a modern spiritual alchemy, where material manipulations are viewed as mere symbols of spiritual transformations.
Today, the discipline is of interest mainly to historians of science and philosophy, and for its mystic, esoteric, and artistic aspects. Nevertheless, alchemy was one of the main precursors of modern sciences, and we owe to the ancient alchemists the discovery of many substances and processes that are the mainstay of modern chemical and metallurgical industries.source: From Wikipedia, the free encyclopedia