Mercury, the liquid metal, certainly known before 300 BC, when it appears in both Eastern and Western sources, was crucial to alchemy. Sulfur, "the stone that burns," was also crucial. It was known from prehistoric times in native deposits and was also given off in metallurgic processes (the "roasting" of sulfide ores).Mercury united with most of the other metals, and the amalgam formed colored powders (the sulfides) when treated with sulfur. Mercury itself occurs in nature in a red sulfide, cinnabar, which can also be made artificially. All of these, except possibly the last, were operations known to the metallurgist and were adopted by the alchemist.
The alchemist added the action on metals of a number of corrosive salts, mainly the vitriols (copper and iron sulfates), alums (the aluminum sulfates of potassium and ammonium), and the chlorides of sodium and ammonium. And he made much of arsenic's property of colouring metals. All of these materials, except the chloride of ammonia, were known in ancient times.
Known as sal ammoniac in the West, nao sha in China, nao sadar in India, and nushadir in Persia and Arabic lands, the chloride of ammonia first became known to the West in the Chou-i ts'an t'ung ch'i, a Chinese treatise of the 2nd century AD.
It was to be crucial to alchemy, for on sublimation it dissociates into antagonistic corrosive materials, ammonia and hydrochloric acid, which readily attack the metals. Until the 9th century it seems to have come from a single source, the Flame Mountain (Huo-yen Shan) near T'u-lu-p'an (Turfan), in Central Asia.
Finally, the manipulation of these materials was to lead to the discovery of the mineral acids, the history of which began in Europe in the 13th century. The first was probably nitric acid, made by distilling together saltpetre (potassium nitrate) and vitriol or alum. More difficult to discover was sulfuric acid, which was distilled from vitriol or alum alone but required apparatus resistant to corrosion and heat. And most difficult was hydrochloric acid, distilled from common salt or sal ammoniac and vitriol or alum, for the vapours of this acid cannot be simply condensed but must be dissolved in water.
"Transmutation" is the key word characterizing alchemy, and it may be understood in several ways: in the changes that are called chemical, in physiological changes such as passing from sickness to health, in a hoped-for transformation from old age to youth, or even in passing from an earthly to a supernatural existence. Alchemical changes seem always to have been positive, never involving degradation except as an intermediate stage in a process having a "happy ending." Alchemy aimed at the great human "goods": wealth, longevity, and immortality.
Alchemy was not original in seeking these goals, for it had been preceded by religion, medicine, and metallurgy. The first chemists were metallurgists, who were perhaps the most successful practitioners of the arts in antiquity. Their theories seem to have come not from science but from folklore and religion. The miner and metallurgist, like the agriculturalist, in this view, accelerate the normal maturation of the fruits of the earth, in a magico-religious relationship with nature. In primitive societies the metallurgist is often a member of an occult religious society.
But the first ventures into natural philosophy, the beginnings of what is called the scientific view, also preceded alchemy. Systems of five almost identical basic elements were postulated in China, India, and Greece, according to a view in which nature comprised antagonistic, opposite forces--hot and cold, positive and negative, and male and female; i.e., primitive versions of the modern conception of energy.
Drawing on a similar astrological heritage, philosophers found correspondences among the elements, planets, and metals. In short, both the chemical arts and the theories of the philosophers of nature had become complex before alchemy appeared. (Crystalinks)
