Editing Phlogiston theory (section)

==Theory==
Phlogiston theory states that ''phlogisticated'' substances contain phlogiston and that they ''dephlogisticate'' when burned, releasing stored phlogiston, which is absorbed by the air. Growing plants then absorb this phlogiston, which is why air does not spontaneously combust and also why plant matter burns. This method of accounting for combustion was inverse to the [[Antoine Lavoisier#Oxygen theory of combustion|oxygen theory]] by Antoine Lavoisier.

<blockquote>In general, substances that burned in the air were said to be rich in phlogiston; the fact that combustion soon ceased in an enclosed space was taken as clear-cut evidence that air had the capacity to absorb only a finite amount of phlogiston. When the air had become completely phlogisticated it would no longer serve to support the combustion of any material, nor would a metal heated in it yield a [[calx]]; nor could phlogisticated air support life.  Breathing was thought to take phlogiston out of the body.<ref>James Bryant Conant, ed. ''The Overthrow of Phlogiston Theory: The Chemical Revolution of 1775–1789''. Cambridge: Harvard University Press (1950), 14. {{OCLC|301515203}}.</ref></blockquote>

[[Joseph Black]]'s Scottish student [[Daniel Rutherford]] discovered [[nitrogen]] in 1772, and the pair used the theory to explain his results. The residue of air left after burning, in fact, a mixture of nitrogen and [[carbon dioxide]], was sometimes referred to as ''phlogisticated air,'' having taken up all of the phlogiston. Conversely, when [[Joseph Priestley]] discovered [[oxygen]], he believed it to be ''dephlogisticated air,'' capable of combining with more phlogiston and thus supporting combustion for longer than ordinary air.<ref>{{cite web |url=http://www.spaceship-earth.de/Biograph/Priestley.htm#4A4FW |title=Priestley, Joseph |publisher=Spaceship-earth.de |access-date=5 June 2009 |url-status=dead |archive-url=https://web.archive.org/web/20090302094050/http://spaceship-earth.de/Biograph/Priestley.htm#4A4FW |archive-date=2 March 2009 }}</ref>