Editing Phlogiston theory (section)

=== Georg Ernst Stahl ===
[[File:Georg Ernst Stahl. Line engraving, 1715. Wellcome V0005595.jpg|thumb|upright|[[Georg Ernst Stahl]]]]

In 1703, [[Georg Ernst Stahl]], a professor of medicine and chemistry at [[University of Halle|Halle]], proposed a variant of the theory in which he renamed Becher's {{Lang|la|terra pinguis}} to ''phlogiston'', and it was in this form that the theory probably had its greatest influence.<ref name="Mason2">Mason, Stephen F., (1962). ''A History of the Sciences'' (revised edition). New York: Collier Books. Ch. 26.</ref> The term 'phlogiston' itself was not something that Stahl invented. There is evidence that the word was used as early as 1606, and in a way that was very similar to what Stahl was using it for.<ref name="White"/> The term was derived from a Greek word meaning inflame. The following paragraph describes Stahl's view of phlogiston:

{{blockquote|To Stahl, metals were compounds containing phlogiston in combination with metallic oxides (calces); when ignited, the phlogiston was freed from the metal leaving the oxide behind. When the oxide was heated with a substance rich in phlogiston, such as charcoal, the calx again took up phlogiston and regenerated the metal. Phlogiston was a definite substance, the same in all its combinations.<ref name="Leicester" />}}

Stahl's first definition of phlogiston first appeared in his {{Lang|la|Zymotechnia fundamentalis}}, published in 1697. His most quoted definition was found in the treatise on chemistry entitled {{Lang|la|Fundamenta chymiae}} in 1723.<ref name="White" /> According to Stahl, phlogiston was a substance that was not able to be put into a bottle but could be transferred nonetheless. To him, wood was just a combination of ash and phlogiston, and making a metal was as simple as getting a metal [[calx]] and adding phlogiston.<ref name="Leicester" /> [[Soot]] was almost pure phlogiston, which is why heating it with a metallic calx transforms the calx into the metal and Stahl attempted to prove that the phlogiston in soot and [[Sulfur|sulphur]] were identical by converting [[sulphate]]s to [[liver of sulphur]] using [[charcoal]]. He did not account for the increase in weight on combustion of tin and lead that were known at the time.{{sfn|Ladenburg|1911|pp=6–7}}