Editing Joseph Priestley (section)

====Discovery of oxygen====
{{see also|Wikisource:The Mouse's Petition}}

[[File:Bowood House laboratory.jpg|thumb|left|The laboratory at Lord Shelburne's estate, [[Bowood House]] in Wiltshire, in which Priestley discovered oxygen|alt=Photograph of a laboratory, with glass-encased, wooden bookcases on two walls and a window on the third. There is a display case in the middle of the room.]]

In August 1774 he isolated an "air" that appeared to be completely new, but he did not have an opportunity to pursue the matter because he was about to tour Europe with Shelburne. While in Paris, Priestley replicated the experiment for others, including French chemist [[Antoine Lavoisier]]. After returning to Britain in January 1775, he continued his experiments and discovered "vitriolic acid air" ([[sulphur dioxide]], SO<sub>2</sub>).{{citation needed|date=February 2024}}

In March he wrote to several people regarding the new "air" that he had discovered in August. One of these letters was read aloud to the Royal Society, and a paper outlining the discovery, titled "An Account of further Discoveries in Air", was published in the Society's journal ''[[Philosophical Transactions]]''.<ref>Priestley, Joseph. "[https://www.jstor.org/pss/106209 An Account of Further Discoveries in Air]". ''[[Philosophical Transactions]]'' 65 (1775): 384–94.</ref> Priestley called the new substance "dephlogisticated air", which he made in the famous experiment by [[burning glass|focusing the sun's rays]] on a sample of [[mercuric oxide]]. He first tested it on mice, who surprised him by surviving quite a while entrapped with the air, and then on himself, writing that it was "five or six times better than common air for the purpose of respiration, inflammation, and, I believe, every other use of common atmospherical air".<ref>Qtd. in Schofield (2004), 107.</ref> He had discovered [[oxygen]] gas (O<sub>2</sub>).{{citation needed|date=February 2024}}

[[File:Shelburne.jpg|thumb|upright|[[William Petty, 2nd Earl of Shelburne|William Petty-Fitzmaurice, 1st Marquess of Landsdowne]] – who sympathised with  [[Unitarianism]]<ref>{{cite book |last1=Wagner |first1=P. |title=Hypoxia |date=2012 |publisher=Springer |page=10 |isbn=978-1-4419-8997-0 |url=https://books.google.com/books?id=XSDjBwAAQBAJ&dq=unitarian+William+Petty,+2nd+Earl+of+Shelburne&pg=PA11 |access-date=2 January 2024}}</ref> – built a laboratory for the famous dissenter at [[Bowood House]].|alt=Half-length portrait of a man wearing furred robes and a white wig and looking regal. Underneath his white robes, he is wearing red and gold and he is sitting in a red chair.]]

[[File:OxygenApparatus.jpg|thumb|alt=Reproduction of Joseph Priestley's oxygen apparatus|Reproduction of Joseph Priestley's oxygen apparatus]]

Priestley assembled his oxygen paper and several others into a second volume of ''Experiments and Observations on Air'', published in 1776. He did not emphasise his discovery of "dephlogisticated air" (leaving it to Part III of the volume) but instead argued in the preface how important such discoveries were to rational religion. His paper narrated the discovery chronologically, relating the long delays between experiments and his initial puzzlements; thus, it is difficult to determine when exactly Priestley "discovered" oxygen.<ref>Schofield (2004), 105–19; see also Jackson, 126–27, 163–64, 166–74; Gibbs, 118–23; Uglow, 229–31, 241; Holt, 93.</ref> Such dating is significant as both Lavoisier and Swedish pharmacist [[Carl Wilhelm Scheele]] have strong claims to the discovery of oxygen as well, Scheele having been the first to isolate the gas (although he published after Priestley) and Lavoisier having been the first to describe it as purified "air itself entire without alteration" (that is, the first to explain oxygen without phlogiston theory).<ref>Kuhn, 53–55.</ref>

In his paper "Observations on Respiration and the Use of the Blood", Priestley was the first to suggest a connection between blood and air, although he did so using [[phlogiston theory]]. In typical Priestley fashion, he prefaced the paper with a history of the study of respiration. A year later, clearly influenced by Priestley, Lavoisier was also discussing respiration at the [[French Academy of Sciences|Académie des sciences]]. Lavoisier's work began the long train of discovery that produced papers on oxygen respiration and culminated in the overthrow of phlogiston theory and the establishment of modern chemistry.<ref>Schofield (2004), 129–30; Gibbs, 124–25.</ref>

Around 1779 Priestley and Shelburne – soon to be the [[Marquess of Lansdowne|1st Marquess of Landsdowne]] – had a rupture, the precise reasons for which remain unclear. Shelburne blamed Priestley's health, while Priestley claimed Shelburne had no further use for him. Some contemporaries speculated that Priestley's outspokenness had hurt Shelburne's political career. Schofield argues that the most likely reason was Shelburne's recent marriage to Louisa Fitzpatrick—apparently, she did not like the Priestleys. Although Priestley considered moving to America, he eventually accepted [[Birmingham]] New Meeting's offer to be their minister.<ref>Schofield (2004), 141–43; see also Jackson, 198–99; Holt, 81–82.</ref>

Both Priestley and Shelburne's families upheld their Unitarian faith for generations. In December 2013, it was reported that [[Sir Christopher Bullock]]—a direct descendant of Shelburne's brother, [[Thomas Fitzmaurice (MP)]]—had married his wife, [[Lupton family|Lady Bullock]], née Barbara May Lupton, at London's Unitarian [[Essex Street Chapel|Essex Church]] in 1917. Barbara Lupton was the second cousin of [[Family of Catherine, Duchess of Cambridge|Olive Middleton]], née Lupton, the great-grandmother of [[Catherine, Duchess of Cambridge]]. In 1914, Olive and Noel Middleton had married at Leeds' [[Mill Hill Chapel]], which Priestley, as its minister, had once guided towards Unitarianism.<ref>{{cite news |last1=Nikkah |first1=Roya |title=The Duchess discovers blue blood in her own family |url=https://www.telegraph.co.uk/news/uknews/kate-middleton/9747412/Duchess-of-Cambridge-discovers-blue-blood-in-her-own-family.html |website=UK Sunday Telegraph |date=16 December 2012 |page=9 |access-date=8 July 2014 |url-status=live |archive-url=https://web.archive.org/web/20141029061649/http://www.telegraph.co.uk/news/uknews/kate-middleton/9747412/Duchess-of-Cambridge-discovers-blue-blood-in-her-own-family.html |archive-date=29 October 2014}}</ref>