Editing Classical element (section)

===Alchemy===
[[File:Vitriol.png|thumb|Seventeenth century alchemical emblem showing the four Classical elements in the corners of the image, alongside the tria prima on the central triangle]]
{{anchor|Elements in Medieval alchemy}}

The elemental system used in medieval [[alchemy]] was developed primarily by the anonymous authors of the Arabic works attributed to Pseudo [[Apollonius of Tyana]].{{sfnp|Norris|2006|pp=43–65}} This system consisted of the four classical elements of air, earth, fire, and water, in addition to a new theory called the [[sulphur-mercury theory of metals]], which was based on two elements: [[Sulfur|sulphur]], characterizing the principle of combustibility, "the stone which burns"; and [[Mercury (element)|mercury]], characterizing the principle of metallic properties. They were seen by early alchemists as idealized expressions of irreducible components of the [[universe]]<ref>{{Cite book |last=Clulee |first=Nicholas H. |title=John Dee's Natural Philosophy |publisher=Routledge |year=1988 |isbn=978-0-415-00625-5 |pages=97}}</ref> and are of larger consideration within philosophical alchemy.

The three metallic principles—sulphur to flammability or combustion, mercury to volatility and stability, and [[Salt (chemistry)|salt]] to solidity—became the ''tria prima'' of the Swiss alchemist [[Paracelsus]]. He reasoned that Aristotle's four element theory appeared in bodies as three principles. Paracelsus saw these principles as fundamental and justified them by recourse to the description of how wood burns in fire. Mercury included the cohesive principle, so that when it left in smoke the wood fell apart. Smoke described the volatility (the mercurial principle), the heat-giving flames described flammability (sulphur), and the remnant ash described solidity (salt).{{sfnp|Strathern|2001|p=79}}