Editing Joseph Priestley

{{Short description|English chemist, theologian, educator, and political theorist (1733–1804)}}
{{for-multi|the English lawyer|Joseph Child Priestley|the British lecturer in botany|Joseph Hubert Priestley}}
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{{Use British English|date=September 2013}}
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{{Infobox person
| name          = <!-- use common name/article title --> Joseph Priestley
| honorific_suffix = {{post-nominals|country=GBR|FRS|size=100%}}
| image         = File:Joseph Priestley.jpeg
| alt           = Joseph Priestley
| caption       = Portrait of Priestley, 1801
| birth_name    = <!-- only use if different from name -->
| birth_date    = <!-- {{Birth date and age|df=yes|YYYY|MM|DD}} for living people supply only the year with {{Birth year and age|YYYY}} unless the exact date is already widely published, as per [[WP:DOB]]. For people who have died, use {{Birth date|df=yes|YYYY|MM|DD}}. --> {{OldStyleDate|24 March|1733|13 March}}
| birth_place   = [[Birstall, West Yorkshire|Birstall]], [[Yorkshire]], England
| death_date    = <!-- {{Death date and age|df=yes|YYYY|MM|DD|YYYY|MM|DD}} (DEATH date then BIRTH date) --> {{Death date and age|df=yes|1804|02|06|1733|03|24}}
| death_place   = [[Northumberland, Pennsylvania]], U.S.
| occupation    = {{hlist|[[Chemist]]|[[natural philosopher]]|[[theologian]]|[[linguist|grammarian]]|[[teacher]]}}
| known_for     = * Discovery of [[oxygen]] (O<sub>2</sub>) and nine other gases, including [[carbon monoxide]] (CO), [[nitric oxide]] (NO), [[nitrous oxide]] (N<sub>2</sub>O), [[ammonia]] (NH<sub>3</sub>), [[sulphur dioxide]] (SO<sub>2</sub>), and [[nitrogen peroxide]] (N<sub>2</sub>O<sub>4</sub>)
* Discovery of the [[carbon cycle]]
| awards        = * [[Fellow of the Royal Society]] (1766)<ref name="FRS">{{cite web |url=http://royalsociety.org/downloaddoc.asp?id=4275 |title=List of Fellows of the Royal Society 1660–2007, K–Z |website=royalsociety.org |publisher=The Royal Society |access-date=1 August 2019 |url-status=dead |archive-url=https://web.archive.org/web/20071212012209/http://royalsociety.org/downloaddoc.asp?id=4275 |archive-date=12 December 2007}}</ref>
* [[Copley Medal]] (1772)<ref name="Copley Medal">{{cite web |url=http://royalsociety.org/page.asp?id=1744 |title=Copley archive winners 1799–1731 |website=royalsociety.org |publisher=The Royal Society |access-date=1 August 2019 |url-status=dead |archive-url=https://web.archive.org/web/20080111085614/http://royalsociety.org/page.asp?id=1744 |archive-date=11 January 2008}}</ref>
}}
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'''Joseph Priestley''' {{post-nominals|country=GBR|FRS}} ({{IPAc-en|ˈ|p|r|iː|s|t|l|i}};<ref>[http://www.collinsdictionary.com/dictionary/american/priestley "Priestley"] {{webarchive|url=https://web.archive.org/web/20141030033729/http://www.collinsdictionary.com/dictionary/american/priestley |date=30 October 2014 }}: ''[[Collins English Dictionary]]'' – Complete & Unabridged 2012 Digital Edition.</ref> 24 March 1733 – 6 February 1804) was an English [[chemist]], Unitarian, [[Natural philosophy|natural philosopher]], [[English Separatist|separatist]] [[theologian]], [[Linguist|grammarian]], multi-subject educator and [[Classical liberalism|classical liberal]] [[Political philosophy|political theorist]].<ref name=oxford2004/> He published over 150 works, and conducted experiments in several areas of science.<ref>[[#isaacson2004|Isaacson, 2004]], pp. 140–141, 289</ref><ref>[[#schofield1997|Schofield, 1997]], p. 142</ref>

Priestley is credited with his independent discovery of [[oxygen]] by the thermal decomposition of mercuric oxide,<ref>{{cite book |title=General Chemistry |edition=4th |author=H.&nbsp;I. Schlesinger |year=1950 |page=134}}</ref> having isolated it in 1774.<ref>Although Swedish chemist [[Carl Wilhelm Scheele]] also has strong claims to the discovery, Priestley published his findings first. Scheele discovered it by heating potassium nitrate, mercuric oxide, and many other substances in about 1772.</ref> During his lifetime, Priestley's considerable scientific reputation rested on his invention of [[carbonated water]], his writings on [[electricity]], and his discovery of several "airs" (gases), the most famous<ref>{{Cite web |title=Joseph Priestley, Discoverer of Oxygen National Historic Chemical Landmark |url=https://www.acs.org/content/acs/en/education/whatischemistry/landmarks/josephpriestleyoxygen.html |access-date=21 May 2021 |website=American Chemical Society |language=en}}</ref> being what Priestley dubbed "dephlogisticated air" (oxygen). Priestley's determination to defend [[phlogiston theory]] and to reject what would become the [[chemical revolution]] eventually left him isolated within the scientific community.

Priestley's science was integral to his theology, and he consistently tried to fuse [[Age of Enlightenment|Enlightenment]] [[rationalism]] with Christian [[theism]].<ref>Tapper, 10.</ref> In his metaphysical texts, Priestley attempted to combine theism, [[materialism]], and [[determinism]], a project that has been called "audacious and original".<ref name=Tap314/> He believed that a proper understanding of the natural world would promote human [[Progress (history)|progress]] and eventually bring about the [[millennialism|Christian millennium]].<ref name=Tap314>Tapper, 314.</ref> Priestley, who strongly believed in the free and open exchange of ideas, advocated [[religious toleration|toleration]] and equal rights for [[English Dissenters|religious Dissenters]], which also led him to help found [[Unitarianism]] [[History of Unitarianism#England|in England]]. The controversial nature of Priestley's publications, combined with his outspoken support of the [[American Revolution]] and later the [[French Revolution]],<ref>[[#vandoren1938|Van Doren]], p. 420</ref><ref>[[#schofield1997|Schofield, 1997]], p. 274</ref> aroused public and governmental contempt; eventually forcing him to flee in 1791, first to London and then to the United States, after a mob [[Priestley Riots|burned down]] his Birmingham home and church. He spent his last ten years in [[Northumberland County, Pennsylvania]].

A scholar and teacher throughout his life, Priestley made significant contributions to [[pedagogy]], including the publication of a seminal work on [[Grammar#History|English grammar]] and books on history; he prepared some of the most influential early timelines. The educational writings were among Priestley's most popular works. Arguably his metaphysical works, however, had the most lasting influence, as now considered primary sources for [[utilitarianism]] by philosophers such as [[Jeremy Bentham]], [[John Stuart Mill]], and [[Herbert Spencer]].

==Early life and education (1733–1755)==
[[File:Coat of Arms of Joseph Priestley.svg|175px|thumb|left|Coat of Arms of Joseph Priestley]]
[[File:PriestleyBirthplace.jpg|thumb|Priestley's birthplace (since demolished) in Fieldhead, [[Birstall, West Yorkshire]] – about six miles (10 km) southwest of [[Leeds]]<ref>Schofield (1997), 2.</ref>|alt=Black-and-white drawing of a two-story brick house along a road.]]

Priestley was born in [[Birstall, West Yorkshire|Birstall]] (near [[Batley]]) in the [[West Riding of Yorkshire]], to an established [[English Dissenters|English Dissenting]] family who did not conform to the [[Church of England]]. He was the oldest of six children born to Mary Swift and Jonas Priestley, a [[finishing (textiles)|finisher]] of cloth. Priestley was sent to live with his grandfather around the age of one. He returned home five years later, after his mother died. When his father remarried in 1741, Priestley went to live with his aunt and uncle, the wealthy and childless Sarah (d. 1764) and John Keighley, {{convert|3|mi|km}} from Fieldhead.<ref name=oxford2004>[[#oxford2004|Gray & Harrison: Oxford Dictionary of National Biography]], pp. 351–352</ref>

Priestley was a precocious child—at the age of four, he could flawlessly recite all 107 questions and answers of the [[Westminster Shorter Catechism]]—and his aunt sought the best education for him, intending him to enter ministry. During his youth, Priestley attended local schools, where he learned Greek, Latin, and Hebrew.<ref>Schofield (1997), 2–12; Uglow, 72; Jackson, 19–25; Gibbs, 1–4; Thorpe, 1–11; Holt, 1–6.</ref>

Around 1749, Priestley became seriously ill and believed he was dying. Raised as a devout [[Calvinist]], he believed a [[Conversion to Christianity|conversion experience]] was necessary for salvation, but doubted he had had one. This emotional distress eventually led him to question his theological upbringing, causing him to reject [[Unconditional election|election]] and to accept [[Christian universalism|universal salvation]]. As a result, the elders of his home church, the [[Independent (religion)|Independent]] Upper Chapel of [[Heckmondwike]], near Leeds, refused him admission as a full member.<ref name=oxford2004/><ref>Schofield (1997), 1, 7–8; Jackson, 25–30; Gibbs, 4; Priestley, ''Autobiography'', 71–73, 123.</ref>

Priestley's illness left him with a permanent [[Stuttering|stutter]] and he gave up any thoughts of entering the ministry at that time. In preparation for joining a relative in trade in [[Lisbon]], he studied French, Italian, and German in addition to [[Aramaic]], and Arabic. He was tutored by the Reverend George Haggerstone, who first introduced him to higher mathematics, [[natural philosophy]], logic, and [[metaphysics]] through the works of [[Isaac Watts]], [[Willem 's Gravesande]], and [[John Locke]].<ref>Schofield (1997), 14, 28–29; Uglow, 72; Gibbs, 5; Thorpe, 11–12; Holt, 7–9.</ref>

===Daventry Academy===
Priestley eventually decided to return to his theological studies and, in 1752, matriculated at [[Daventry Academy|Daventry]], a Dissenting academy.<ref>Schofield (1997), 28–29; Jackson, 30; Gibbs, 5.</ref> Because he was already widely read, Priestley was allowed to omit the first two years of coursework. He continued his intense study; this, together with the liberal atmosphere of the school, shifted his theology further leftward and he became a [[English Dissenters#Rational Dissenters|Rational Dissenter]]. Abhorring dogma and religious mysticism, Rational Dissenters emphasised rational analysis of the natural world and the Bible.<ref>McEvoy (1983), 48–49.</ref>

Priestley later wrote that the book that influenced him the most, save the Bible, was [[David Hartley (philosopher)|David Hartley]]'s ''[[Observations on Man]]'' (1749). Hartley's psychological, philosophical, and theological treatise postulated a material [[Philosophy of mind|theory of mind]].<!-- "philosophy of mind" link is better than "theory of mind" --> Hartley aimed to construct a Christian philosophy in which both religious and moral "facts" could be scientifically proven, a goal that would occupy Priestley for his entire life. In his third year at Daventry, Priestley committed himself to the ministry, which he described as "the noblest of all professions".<ref>Qtd. in Jackson, 33. See Schofield (1997), 40–57; Uglow, 73–74; Jackson, 30–34; Gibbs, 5–10; Thorpe, 17–22; Tapper, 314; Holt, 11–14; Garrett, 54.</ref>

==Needham Market and Nantwich (1755–1761)==
{{further|Joseph Priestley and education}}
[[File:PriestleyGrammar.png|left|upright|thumb|Title page of ''[[The Rudiments of English Grammar|Rudiments of English Grammar]]'' (1761)|alt=Page reads: "The Rudiments of English Grammar; Adapted to the Use of Schools, with Observations on Style. By Joseph Priestley. London: Printed for R. Griffiths, in the Strand. M.DCC.LXI."]]

[[Robert E. Schofield|Robert Schofield]], Priestley's major modern biographer, describes his first "call" in 1755 to the Dissenting parish in [[Needham Market]], Suffolk, as a "mistake" for both Priestley and the congregation.<ref>Schofield (1997), 62–69.</ref> Priestley yearned for urban life and theological debate, whereas Needham Market was a small, rural town with a congregation wedded to tradition. Attendance and donations dropped sharply when they discovered the extent of his [[heterodoxy]]. Although Priestley's aunt had promised her support if he became a minister, she refused any further assistance when she realised he was no longer a Calvinist. To earn extra money, Priestley proposed opening a school, but local families informed him that they would refuse to send their children. He also presented a series of scientific lectures titled "Use of the Globes" that was more successful.<ref>Schofield (1997), 62–69; Jackson, 44–47; Gibbs, 10–11; Thorpe, 22–29; Holt, 15–19.</ref>

Priestley's Daventry friends helped him obtain another position and in 1758 he moved to [[Nantwich]], Cheshire, living at [[Sweetbriar Hall]] in the town's Hospital Street; his time there was happier. The congregation cared less about Priestley's heterodoxy and he successfully established a school. Unlike many schoolmasters of the time, Priestley taught his students [[natural philosophy]] and even bought scientific instruments for them. Appalled at the quality of the available English grammar books, Priestley wrote his own: ''[[The Rudiments of English Grammar]]'' (1761).<ref>Priestley, Joseph. ''[[The Rudiments of English Grammar]]; adapted to the use of schools. With observations on style''. London: Printed for R. Griffiths, 1761.</ref> His innovations in the description of English grammar, particularly his efforts to dissociate it from [[Grammar#History|Latin grammar]], led 20th-century scholars to describe him as "one of the great grammarians of his time".<ref>Qtd. in Schofield (1997), 79.</ref> After the publication of ''Rudiments'' and the success of Priestley's school, [[Warrington Academy]] offered him a teaching position in 1761.<ref>Schofield (1997), 77–79, 83–85; Uglow, 72; Jackson 49–52; Gibbs, 13–16; Thorpe, 30–32; Holt, 19–23.</ref>

==Warrington Academy (1761–1767)==
[[File:Priestley Mary.jpg|thumb|right|upright|alt=Quarter-length portrait of a woman in a brown and grey lace bonnet adorned with a bow and leaning on her right hand.| Mary Priestley, by [[Carl Frederik von Breda|Carl F. von Breda]] (1793);<ref>McLachlan, ''Iconography'', 24–26.</ref> daughter of [[ironmaster]] [[Isaac Wilkinson]], sister of industrialist [[John Wilkinson (industrialist)|John Wilkinson]]]]

In 1761, Priestley moved to [[Warrington]] in [[Cheshire]] and assumed the post of tutor of modern languages and rhetoric at [[Warrington Academy|the town's Dissenting academy]], although he would have preferred to teach mathematics and natural philosophy. He fitted in well at Warrington, and made friends quickly.<ref name="Schofield">{{cite book |last1=Schofield |first1=Robert E. |title=Enlightened joseph priestley : a study of his life and work from 1773 to 1804. |date=2009 |publisher=Penn State Univ Press |location=University Park |isbn=978-0-271-03625-0 |url=https://books.google.com/books?id=nGHiCgAAQBAJ&pg=PT57 |access-date=26 June 2018}}</ref> These included the doctor and writer [[John Aikin]], his sister the children's author [[Anna Laetitia Barbauld|Anna Laetitia Aikin]], and the potter and businessman [[Josiah Wedgwood]]. Wedgwood met Priestley in 1762, after a fall from his horse. Wedgwood and Priestley met rarely, but exchanged letters, advice on chemistry, and laboratory equipment. Wedgwood eventually created a medallion of Priestley in cream-on-blue [[jasperware]].<ref name="Distillations">{{cite journal |last1=Meyer |first1=Michal |title=Old Friends |url=https://www.sciencehistory.org/distillations/magazine/old-friends |journal=Distillations |date=2018 |volume=4 |issue=1 |pages=6–9 |access-date=26 June 2018}}</ref><ref name="Bowden"/>{{rp|37}}

On 23 June 1762, Priestley married Mary Wilkinson of [[Wrexham]]. Of his marriage, Priestley wrote:
<blockquote>
This proved a very suitable and happy connexion, my wife being a woman of an excellent understanding, much improved by reading, of great fortitude and strength of mind, and of a temper in the highest degree affectionate and generous; feeling strongly for others, and little for herself. Also, greatly excelling in every thing relating to household affairs, she entirely relieved me of all concern of that kind, which allowed me to give all my time to the prosecution of my studies, and the other duties of my station.<ref>Priestley, ''Autobiography'', 87.</ref>
</blockquote>
On 17 April 1763, they had a daughter, whom they named Sarah after Priestley's aunt.<ref>See Thorpe, 33–44 for a description of life at Warrington; Schofield (1997), 89–90, 93–94; Jackson, 54–58; Uglow, 73–75; Thorpe, 47–50; Holt, 27–28.</ref>

===Educator and historian===
{{further|Joseph Priestley and education}}

All of the books Priestley published while at Warrington emphasised the study of history; Priestley considered it essential for worldly success as well as religious growth. He wrote histories of science and Christianity in an effort to reveal the progress of humanity and, paradoxically, the loss of a pure, "primitive Christianity".<ref>Sheps, 135, 149; Holt, 29–30.</ref>

[[File:A New Chart of History.jpg|thumb|left|alt=A timeline, showing major civilisations|A redacted version of ''[[A New Chart of History]]'' (1765); Priestley believed this chart would "impress" upon students "a just image of the rise, progress, extent, duration, and contemporary state of all the considerable empires that have ever existed in the world"<ref>Qtd. in Sheps, 146.</ref>]]

In his ''[[Essay on a Course of Liberal Education for Civil and Active Life]]'' (1765),<ref>Priestley, Joseph. ''[[Essay on a Course of Liberal Education for Civil and Active Life]]''. London: Printed for C. Henderson under the Royal Exchange; T. Becket and De Hondt in the Strand; and by J. Johnson and Davenport, in Pater-Noster-Row, 1765.</ref> ''[[Lectures on History and General Policy]]'' (1788), and other works, Priestley argued that the education of the young should anticipate their future practical needs. This principle of utility guided his unconventional curricular choices for Warrington's aspiring middle-class students. He recommended modern languages instead of classical languages and modern rather than ancient history. Priestley's lectures on history were particularly revolutionary; he narrated a [[providentialism|providentialist]] and naturalist account of history, arguing that the study of history furthered the comprehension of God's natural laws. Furthermore, his [[millennialism|millennial]] perspective was closely tied to his optimism regarding scientific progress and the improvement of humanity. He believed that each age would improve upon the previous and that the study of history allowed people to perceive and to advance this progress. Since the study of history was a moral imperative for Priestley, he also promoted the education of middle-class women, which was unusual at the time.<ref>Thorpe, 52–54; Schofield (1997), 124–25; Watts, 89, 95–97; Sheps, 136.</ref> Some scholars of education have described Priestley as the most important English writer on education between the 17th-century [[John Locke]] and the 19th-century [[Herbert Spencer]].<ref>Schofield (1997), 121; see also Watts, 92.</ref> ''Lectures on History'' was well received and was employed by many educational institutions, such as New College at Hackney,<!-- Is this [[Homerton College, Cambridge]]? --> [[Brown University|Brown]], [[Princeton University|Princeton]], [[Yale]], and [[University of Cambridge|Cambridge]].<ref>Schofield (2004), 254–59; McLachlan (1987–90), 255–58; Sheps, 138, 141; Kramnick, 12; Holt, 29–33.</ref> Priestley designed two ''Charts'' to serve as visual study aids for his ''Lectures''.<ref>Priestley, Joseph. ''[[A Chart of Biography]]''. London: J. Johnson, St. Paul's Church Yard, 1765 and Joseph Priestley, ''A Description of a Chart of Biography''. Warrington: Printed by William Eyres, 1765 and Joseph Priestley, ''[[A New Chart of History]]''. London: Engraved and published for J. Johnson, 1769; ''A Description of a New Chart of History''. London: Printed for J. Johnson, 1770.</ref> These charts are in fact timelines; they have been described as the most influential timelines published in the 18th century.<ref>Rosenberg, 57–65 and ff.</ref> Both were popular for decades, and the trustees of Warrington were so impressed with Priestley's lectures and charts that they arranged for the [[University of Edinburgh]] to grant him a [[Doctor of Laws|Doctor of Law]] degree in 1764.<ref>Gibbs, 37; Schofield (1997), 118–19.</ref> During this period Priestley also regularly delivered lectures on rhetoric that were later published in 1777 as ''A Course of Lectures on Oratory and Criticism''.<ref>J. Priestley. ''A Course of Lectures on Oratory and Criticism''. London, 1777. Ed. V. M. Bevilacqua & R. Murphy. Carbondale: Southern Illinois University Press, 1965.</ref>

====History of electricity====
[[File:Familiar Introduction to Electricity by Joseph Priestly, plate 7.jpg|thumb|upright|Priestley's "electrical machine for amateur experimentalists", illustrated in the first edition of his ''Familiar Introduction to the Study of Electricity'' (1768)]]<!-- Please don't correct "Priestly" within the filename as this will cause the image to disappear. Thank you. -->

The intellectually stimulating atmosphere of Warrington, often called the "Athens of the North" (of England) during the 18th century, encouraged Priestley's growing interest in natural philosophy. He gave lectures on anatomy and performed experiments regarding temperature with another tutor at Warrington, his friend [[John Seddon of Warrington|John Seddon]].<ref>Schofield (1997), 136–37; Jackson, 57–61.</ref> Despite Priestley's busy teaching schedule, he decided to write a history of electricity. Friends introduced him to the major experimenters in the field in Britain—[[John Canton]], [[William Watson (scientist)|William Watson]], [[Timothy Lane]], and the visiting [[Benjamin Franklin]] who encouraged Priestley to perform the experiments he wanted to include in his history. Priestley also consulted with Franklin during the latter's kite experiments.<ref>[[#isaacson2004|Isaacson, 2004]], pp. 140–141, 182</ref><ref>[[#vandoren1938|Van Doren]], pp. 164–165</ref> In the process of replicating others' experiments, Priestley became intrigued by unanswered questions and was prompted to undertake experiments of his own design.<ref>Schofield (1997), 141–42, 152; Jackson, 64; Uglow 75–77; Thorpe, 61–65.</ref> (Impressed with his ''Charts'' and the manuscript of his history of electricity, Canton, Franklin, Watson, and [[Richard Price]] nominated Priestley for a fellowship in the [[Royal Society]]; he was accepted in 1766.)<ref>Schofield (1997), 143–44; Jackson, 65–66; see Schofield (1997), 152 and 231–32 for an analysis of the different editions.</ref>
[[File:Priestly-9.jpg|alt=Title page to The History and Present State of Electricity (1769)|thumb|upright|Title page to ''The History and Present State of Electricity'' (1769)]]
In 1767, the 700-page ''[[The History and Present State of Electricity]]'' was published to positive reviews.<ref>Priestley, Joseph. ''[[The History and Present State of Electricity]], with original experiments''. London: Printed for J. Dodsley, J. Johnson and T. Cadell, 1767.</ref> The first half of the text is a history of the study of electricity to 1766; the second and more influential half is a description of contemporary theories about electricity and suggestions for future research. The volume also contains extensive comments on Priestley's views that scientific inquiries be presented with all reasoning in one's discovery path, including false leads and mistakes. He contrasted his narrative approach with Newton's analytical proof-like approach which did not facilitate future researchers to continue the inquiry. Priestley reported some of his own discoveries in the second section, such as the [[Electrical conductivity|conductivity]] of [[charcoal]] and other substances and the continuum between conductors and non-conductors.<ref name=S14456>Schofield (1997), 144–56.</ref> This discovery overturned what he described as "one of the earliest and universally received maxims of electricity", that only water and metals could conduct electricity. This and other experiments on the electrical properties of materials and on the electrical effects of chemical transformations demonstrated Priestley's early and ongoing interest in the relationship between chemical substances and electricity.<ref>Schofield (1997), 156–57; Gibbs 28–31; see also Thorpe, 64.</ref> Based on experiments with charged spheres, Priestley was among the first to propose that electrical force followed an [[inverse-square law]], similar to [[Newton's law of universal gravitation]].<ref>Other early investigators who suspected that the electrical force diminished with distance as the gravitational force did (i.e., as the inverse square of the distance) included [[Daniel Bernoulli]] (see: Abel Socin (1760)  ''Acta Helvetia'', vol. 4, pp. 224–25.) and [[Alessandro Volta]], both of whom measured the force between plates of a capacitor, and [[Franz Aepinus|Aepinus]]. See: J.L. Heilbron, ''Electricity in the 17th and 18th Centuries: A Study of Early Modern Physics'' (Los Angeles, California: University of California Press, 1979), pp. 460–62,  [https://books.google.com/books?id=UlTLRUn1sy8C&pg=PA464 464] {{webarchive|url=https://web.archive.org/web/20160514033716/https://books.google.com/books?id=UlTLRUn1sy8C&pg=PA464 |date=14 May 2016 }} (including footnote 44).</ref><ref>Joseph Priestley, ''The History and Present State of Electricity, with Original Experiments'' (London, England: 1767), [https://books.google.com/books?id=HZE_AAAAcAAJ&pg=PA732 p. 732] {{webarchive|url=https://web.archive.org/web/20160528211919/https://books.google.com/books?id=HZE_AAAAcAAJ&pg=PA732 |date=28 May 2016 }}:<br /><blockquote>May we not infer from this experiment, that the attraction of electricity is subject to the same laws with that of gravitation, and is therefore according to the squares of the distances; since it is easily demonstrated, that were the earth in the form of a shell, a body in the inside of it would not be attracted to one side more than another?</blockquote></ref> He did not generalise or elaborate on this,<ref name=S14456/> and the [[Coulomb's law|general law]] was enunciated by French physicist [[Charles-Augustin de Coulomb]] in the 1780s.<ref>Coulomb (1785) [https://books.google.com/books?id=by5EAAAAcAAJ&pg=PA569 "Premier mémoire sur l'électricité et le magnétisme,"] ''Histoire de l'Académie Royale des Sciences'', pp. 569–577</ref>

Priestley's strength as a natural philosopher was qualitative rather than quantitative and his observation of "a current of real air" between two electrified points would later interest [[Michael Faraday]] and [[James Clerk Maxwell]] as they investigated [[electromagnetism]]. Priestley's text became the standard history of electricity for over a century; [[Alessandro Volta]] (who later invented the battery), [[William Herschel]] (who discovered [[infrared radiation]]), and [[Henry Cavendish]] (who discovered [[hydrogen]]) all relied upon it. Priestley wrote a popular version of the ''History of Electricity'' for the general public titled ''A Familiar Introduction to the Study of Electricity'' (1768).<ref>Priestley, Joseph. ''A Familiar Introduction to the Study of Electricity''. London: Printed for J. Dodsley; T. Cadell; and J. Johnson, 1768.</ref> He marketed the book with his brother Timothy, but unsuccessfully.<ref>Schofield (1997), 228–30.</ref><!--|alt=An illustration of a machine that generated electricity through a wheel and attached to the side of a table.-->

==Leeds (1767–1773)==
[[File:PriestleyLeeds.jpg|thumb|left|upright|alt=Half-length portrait of a man holding a small book in his right hand. He is wearing a black jacket and a white shirt.|The earliest known portrait of Priestley, known as the "Leeds" portrait ({{Circa|1763}}); except for his membership on the Leeds Library Committee, Priestley was not active in the town's social life<ref>Schofield (1997), 162–64.</ref>]]

Perhaps prompted by Mary Priestley's ill health, or financial problems, or a desire to prove himself to the community that had rejected him in his childhood, Priestley moved with his family from Warrington to [[Leeds]] in 1767, and he became [[Mill Hill Chapel]]'s minister. Two sons were born to the Priestleys in Leeds: Joseph, Junior,  on 24 July 1768 and [[William Priestley (Louisiana planter)|William]] three years later. [[Theophilus Lindsey]], a [[Rector (ecclesiastical)|rector]] at [[Catterick, North Yorkshire|Catterick, Yorkshire]], became one of Priestley's few friends in Leeds, of whom he wrote: "I never chose to publish any thing of moment relating to theology, without consulting him."<ref>Priestley, ''Autobiography'', 98; see also Schofield (1997), 163.</ref> Although Priestley had extended family living around Leeds, they do not appear to have communicated. Schofield conjectures that they considered him a [[Heresy|heretic]].<ref>Schofield (1997), 162, note 7.</ref> Each year, Priestley travelled to London to consult with his close friend and publisher, [[Joseph Johnson (publisher)|Joseph Johnson]], and to attend meetings of the Royal Society.<ref>Schofield, (1997), 158, 164; Gibbs, 37; Uglow, 170.</ref>

===Minister of Mill Hill Chapel===
{{further|Joseph Priestley and education|Joseph Priestley and Dissent}}

When Priestley became its minister, [[Mill Hill Chapel]] was one of the oldest and most respected Dissenting congregations in England; however, during the early 18th century the congregation had fractured along doctrinal lines and was losing members to the charismatic [[Methodism#Wesleyan revival|Methodist movement]].<ref>Schofield (1997), 165–69; Holt, 42–43.</ref> Priestley believed that he could strengthen the bonds of the congregation by educating the young people there.<ref>Schofield (1997), 170–71; Gibbs, 37; Watts, 93–94; Holt, 44.</ref>

In his three-volume ''[[Institutes of Natural and Revealed Religion]]'' (1772–74),<ref>Priestley. ''[[Institutes of Natural and Revealed Religion]]''. London: Printed for J. Johnson, Vol. I, 1772, Vol. II, 1773, Vol. III, 1774.</ref> Priestley outlined his theories of religious instruction. More importantly, he laid out his belief in [[Socinianism]]. The doctrines he explicated would become the standards for [[Unitarianism|Unitarians]] in Britain. This work marked a change in Priestley's theological thinking that is critical to understanding his later writings—it paved the way for his [[materialism]] and [[necessitarianism]] (the latter being the belief that a divine being acts in accordance with necessary metaphysical laws).<ref>Miller, xvi; Schofield (1997), 172.</ref>

[[File:PriestleyInstitutes.png|thumb|upright|alt=Page reads: "Institutes of Natural and Revealed Religion. In Two Volumes. Two which is prefixed, An Essay on the best Method of communicating religious Knowledge to the Members of Christian Societies. By Joseph Priestley, LL.D. F.R.S. The Second Edition. vol. I. Wisdom is the principal Thing. Solomon. Birmingham, Printed by Pearson and Rollason, for J. Johnson, No. 72, St. Paul's Church-Yard, London. M DCC LXXXIII."|Priestley had been working on ''[[Institutes of Natural and Revealed Religion]]'' since his Daventry days.]] 
Priestley's major argument in the ''Institutes'' was that the only revealed religious truths that could be accepted were those that matched one's experience of the natural world. Since his views of religion were tied deeply to his understanding of nature, the text's [[theism]] rested on the [[argument from design]].<ref>Schofield (1997), 174; Uglow, 169; Tapper, 315; Holt, 44.</ref> The ''Institutes'' shocked and appalled many readers, primarily because it challenged basic Christian orthodoxies, such as the [[Christ|divinity of Christ]] and the [[Virgin birth of Jesus|miracle of the Virgin Birth]]. Methodists in Leeds penned a hymn asking God to "the Unitarian fiend expel / And chase his doctrine back to Hell."<ref>Qtd. in Jackson, 102.</ref> Priestley wanted to return Christianity to its "primitive" or "pure" form by eliminating the "corruptions" which had accumulated over the centuries. The fourth part of the ''Institutes'', ''[[An History of the Corruptions of Christianity]]'', became so long that he was forced to issue it separately in 1782. Priestley believed that the ''Corruptions'' was "the most valuable" work he ever published. In demanding that his readers apply the logic of the emerging sciences and comparative history to the Bible and Christianity, he alienated religious and scientific readers alike—scientific readers did not appreciate seeing science used in the defence of religion and religious readers dismissed the application of science to religion.<ref>McLachlan (1987–90), 261; Gibbs, 38; Jackson, 102; Uglow, 169.</ref>

===Religious controversialist===
Priestley engaged in numerous political and religious [[pamphlet]] wars. According to Schofield, "he entered each controversy with a cheerful conviction that he was right, while most of his opponents were convinced, from the outset, that he was willfully and maliciously wrong. He was able, then, to contrast his sweet reasonableness to their personal rancor",<ref name=S181>Schofield (1997), 181.</ref> but as Schofield points out Priestley rarely altered his opinion as a result of these debates.<ref name=S181/> While at Leeds he wrote controversial pamphlets on the [[Eucharist|Lord's Supper]] and on Calvinist doctrine; thousands of copies were published, making them some of Priestley's most widely read works.<ref>See Schofield (1997), 181–88 for analysis of these two controversies.</ref>

Priestley founded the ''[[Theological Repository]]'' in 1768, a journal committed to the open and rational inquiry of theological questions. Although he promised to print any contribution, only like-minded authors submitted articles. He was, therefore, obliged to provide much of the journal's content himself. This material also became the basis for many of his later theological and metaphysical works. After only a few years, due to a lack of funds, he was forced to cease publishing the journal.<ref>See Schofield (1997), 193–201 for an analysis of the journal; Uglow, 169; Holt, 53–55.</ref> However, he did revive it briefly in 1784 with similar results.<ref>See Schofield (2004), 202–07 for an analysis of Priestley's contributions.</ref>

===Defender of Dissenters and political philosopher===
{{further|Joseph Priestley and Dissent}}

[[File:PriestleyFirstPrinciples.jpg|thumb|upright|His ''[[Essay on the First Principles of Government]]'' (1768) influenced early 19th-century political philosophers, including [[Jeremy Bentham]].<ref>Schofield (1997), 207.</ref>|alt=Page reads: "An Essay on the First Principles of Government, and on the Nature of Political, Civil, and Religious Liberty, including Remarks on Dr. Brown's Code of Education, and on Br. Balguy's Sermon on Church Authority. The Second Edition, corrected and enlarged, by Joseph Priestley, LL.D. F.R.S. London: Printed for J. Dodsley, in Pall-Mall; T. Cadell, (successor to Mr. Millar) in the Strand; and J. Johnson, No. 72 in St. Paul's Church-Yard. MDCCLXXI."]]

Many of Priestley's political writings supported the repeal of the [[Test Act|Test]] and [[Corporation Act 1661|Corporation Acts]], which restricted the rights of Dissenters. They could not hold political office, serve in the armed forces, or attend Oxford and Cambridge unless they subscribed to the [[Thirty-nine Articles]] of the Church of England. Dissenters repeatedly petitioned Parliament to repeal the Acts, arguing that they were being treated as second-class citizens.<ref>Schofield (1997), 202–05; Holt, 56–64.</ref>

Priestley's friends, particularly other Rational Dissenters, urged him to publish a work on the injustices experienced by Dissenters; the result was his ''[[Essay on the First Principles of Government]]'' (1768).<ref>Priestley, Joseph. ''[[Essay on the First Principles of Government]]; and on the nature of political, civil, and religious liberty''. London: Printed for J. Dodsley; T. Cadell; and J. Johnson, 1768.</ref> An early work of [[Liberalism|modern liberal political theory]] and Priestley's most thorough treatment of the subject, it—unusually for the time—distinguished political rights from civil rights with precision and argued for expansive civil rights. Priestley identified separate private and public spheres, contending that the government should have control only over the public sphere. Education and religion, in particular, he maintained, were matters of private conscience and should not be administered by the state. Priestley's later [[Radicals (UK)|radicalism]] emerged from his belief that the British government was infringing upon these individual freedoms.<ref>Gibbs, 39–43; Uglow, 169; Garrett, 17; Tapper, 315; Holt, 34–37; Philip (1985); Miller, xiv.</ref>

Priestley also defended the rights of Dissenters against the attacks of [[William Blackstone]], an eminent legal theorist, whose ''[[Commentaries on the Laws of England]]'' (1765–69) had become the standard legal guide. Blackstone's book stated that dissent from the Church of England was a crime and that Dissenters could not be loyal subjects. Furious, Priestley lashed out with his ''Remarks on Dr. Blackstone's Commentaries'' (1769), correcting Blackstone's interpretation of the law, his grammar (a highly politicised subject at the time), and history.<ref>Priestley, Joseph. ''Remarks on some paragraphs in the fourth volume of Dr. Blackstone's Commentaries on the laws of England, relating to the Dissenters''. London: Printed for J. Johnson and J. Payne, 1769.</ref> Blackstone, chastened, altered subsequent editions of his ''Commentaries'': he rephrased the offending passages and removed the sections claiming that Dissenters could not be loyal subjects, but he retained his description of Dissent as a crime.<ref>Schofield (1997), 214–16; Gibbs, 43; Holt, 48–49.</ref>

===Natural philosopher: electricity, ''Optics'', and carbonated water===
[[File:Joseph Priestley's book Optics.jpg|thumb|''Optics: The History and Present State of Vision, Light, and Colours'', published in 1772, London]]
Although Priestley claimed that [[natural philosophy]] was only a hobby, he took it seriously. In his ''History of Electricity'', he described the scientist as promoting the "security and happiness of mankind".<ref>Qtd. in Kramnick, 8.</ref> Priestley's science was eminently practical and he rarely concerned himself with theoretical questions; his model was his close friend, Benjamin Franklin.<ref>[[#kramnick1981|Kramnick, 1981]], p. 10</ref> When he moved to [[Leeds]], Priestley continued his electrical and chemical experiments (the latter aided by a steady supply of carbon dioxide from a neighbouring brewery). Between 1767 and 1770, he presented five papers to the Royal Society from these initial experiments; the first four papers explored [[coronal discharge]]s and other phenomena related to [[electrical discharge]], while the fifth reported on the conductivity of charcoals from different sources. His subsequent experimental work focused on chemistry and [[pneumatics]].<ref>Schofield (1997), 227, 232–38; see also Gibbs, 47; Kramnick, 9–10.</ref>

Priestley published the first volume of his projected history of experimental philosophy,<!-- do not link to [[experimental philosophy]] – that page describes a separate modern discipline --> ''The History and Present State of Discoveries Relating to Vision, Light and Colours'' (referred to as his ''Optics''), in 1772.<ref>Priestley, Joseph. ''Proposals for printing by subscription, The history and present state of discoveries relating to vision, light, and colours''. Leeds: n.p., 1771.</ref> He paid careful attention to the history of optics and presented excellent explanations of early optics experiments, but his mathematical deficiencies caused him to dismiss several important contemporary theories. He followed the (corpuscular) particle theory of light, influenced by the works of Reverend [[John Rowning]] and others.<ref>{{Cite journal |last=Moura |first=Breno |date=2018 |title=Newtonian Optics and the Historiography of Light in the 18th Century: A critical Analysis of Joseph Priestley's The History of Optics |url=https://periodicos.ufmg.br/index.php/transversal/article/view/15045 |journal=Transversal: International Journal for the Historiography of Science |issue=5 |doi=10.24117/2526-2270.2018.i5.12 |s2cid=239593348 |issn=2526-2270 |doi-access=free}}</ref> Furthermore, he did not include any of the practical sections that had made his ''History of Electricity'' so useful to practising natural philosophers. Unlike his ''History of Electricity'', it was not popular and had only one edition, although it was the only English book on the topic for 150 years. The hastily written text sold poorly; the cost of researching, writing, and publishing the ''Optics'' convinced Priestley to abandon his history of experimental philosophy.<ref>Schofield (1997), 240–49; Gibbs, 50–55; Uglow, 134.</ref>

{{external media | width = 210px | float = right | headerimage= | audio1 = [https://www.sciencehistory.org/distillations/podcast/fizzy-water "Fizzy Water"], ''Distillations'' Podcast Episode 217, [[Science History Institute]]}}

Priestley was considered for the position of astronomer on [[James Cook]]'s [[James Cook#Second voyage (1772–1775)|second voyage to the South Seas]], but was not chosen. Still, he contributed in a small way to the voyage: he provided the crew with a method for making [[carbonated water]], which he erroneously speculated might be a cure for [[scurvy]]. He then published a pamphlet with ''Directions for Impregnating Water with Fixed Air'' (1772).<ref>Priestley, Joseph. ''Directions for impregnating water with fixed air; in order to communicate to it the peculiar spirit and virtues of Pyrmont water, and other mineral waters of a similar nature''. London: Printed for J. Johnson, 1772.</ref> Priestley did not exploit the commercial potential of carbonated water, but others such as {{nowrap|[[Johann Jacob Schweppe|J. J. Schweppe]]}} made fortunes from it.<ref>Schofield (1997), 256–57; Gibbs, 57–59; Thorpe, 76–79; Uglow, 134–36, 232–34.</ref> For his discovery of carbonated water Priestley has been labelled "the father of the [[soft drink]]",<ref>{{cite book |last1=Schils |first1=René |title=How James Watt Invented the Copier: Forgotten Inventions of Our Great Scientists |date=2011 |publisher=Springer Science & Business Media |page=36}}</ref> with the beverage company [[Schweppes]] regarding him as "the father of our industry".<ref>{{cite book |last1=LaMoreaux |first1=Philip E. |title=Springs and Bottled Waters of the World: Ancient History, Source, Occurrence, Quality and Use |date=2012 |publisher=Springer Science & Business Media |page=135}}</ref> In 1773, the Royal Society recognised Priestley's achievements in natural philosophy by awarding him the [[Copley Medal]].<ref name="Copley Medal"/><ref>Schofield (1997), 251–55; see Holt, 64; Gibbs, 55–56; and Thorpe, 80–81, for the traditional account of this story.</ref>

Priestley's friends wanted to find him a more financially secure position. In 1772, prompted by [[Richard Price]] and Benjamin Franklin, [[William Petty, 2nd Earl of Shelburne|Lord Shelburne]] wrote to Priestley asking him to direct the education of his children and to act as his general assistant. Although Priestley was reluctant to sacrifice his ministry, he accepted the position, resigning from Mill Hill Chapel on 20 December 1772, and preaching his last sermon on 16 May 1773.<ref>Schofield (1997), 270–71; Jackson, 120–22; Gibbs, 84–86; Uglow, 239–40; Holt, 64–65.</ref>

==Calne (1773–1780)==
[[File:Portrait of Joseph Priestley by Henry Fuseli.jpg|thumb|left|upright|alt=Portrait of a man sitting on a chair and leaning against a table with books and papers.|A portrait of Priestley commissioned by his publisher and close friend [[Joseph Johnson (publisher)|Joseph Johnson]] from [[Henry Fuseli]] ({{Circa|1783}})<ref>McLachlan, ''Iconography'', 19–20.</ref>]]

In 1773, the Priestleys moved to [[Calne]] in [[Wiltshire]], and a year later [[William Petty, 2nd Earl of Shelburne|Lord Shelburne]] and Priestley took a tour of Europe. According to Priestley's close friend [[Theophilus Lindsey]], Priestley was "much improved by this view of mankind at large".<ref>Qtd. in Gibbs, 91.</ref> Upon their return, Priestley easily fulfilled his duties as librarian and tutor. The workload was intentionally light, allowing him time to pursue his scientific investigations and theological interests. Priestley also became a political adviser to Shelburne, gathering information on parliamentary issues and serving as a liaison between Shelburne and the Dissenting and American interests. When the Priestleys' third son was born on 24 May 1777, they named him Henry at the lord's request.<ref>Schofield (2004), 4–11, 406; Gibbs, 91–94; Jackson, 122, 124, 143–52, 158–62; Thorpe, 80–85; Watts, 96; Holt, 70–94 (includes large quotations from Priestley's letters sent from Europe to Shelburne's sons).</ref>

===Materialist philosopher===
{{further|Joseph Priestley and Dissent}}

Priestley wrote his most important philosophical works during his years with Lord Shelburne. In a series of major [[Metaphysics|metaphysical]] texts published between 1774 and 1780—''An Examination of Dr. Reid's Inquiry into the Human Mind'' (1774), ''Hartley's Theory of the Human Mind on the Principle of the Association of Ideas'' (1775), ''[[Disquisitions relating to Matter and Spirit]]'' (1777), ''[[The Doctrine of Philosophical Necessity Illustrated]]'' (1777), and ''[[Letters to a Philosophical Unbeliever]]'' (1780)—he argues for a philosophy that incorporates four concepts: [[determinism]], [[materialism]], [[causality|causation]], and [[necessitarianism]]. By studying the natural world, he argued, people would learn how to become more compassionate, happy, and prosperous.<ref>McEvoy and McGuire, 326–27; Tapper, 316.</ref>

[[File:PriestleyMatterSpirit.png|thumb|upright|alt=Page reads: "Disquisitions relating to Matter and Spirit. To which is added, The History of the Philosophical Doctrine concerning the Origin of the Soul, and the Nature of Matter; with its Influence on Christianity, especially with Respect to the Doctrine of the Pre-existence of Christ."|By 1782, at least a dozen hostile refutations were published to ''[[Disquisitions relating to Matter and Spirit]]'', and Priestley was branded an [[atheist]].<ref>Schofield (2004), 72.</ref>]] 
Priestley strongly suggested that there is no [[Dualism (philosophy of mind)|mind-body duality]], and put forth a materialist philosophy in these works; that is, one founded on the principle that everything in the universe is made of matter that we can perceive. He also contended that discussing the soul is impossible because it is made of a divine substance, and humanity cannot perceive the divine. Despite his separation of the divine from the mortal, this position shocked and angered many of his readers, who believed that such a duality was necessary for the [[Soul (spirit)|soul]] to exist.<ref>Schofield (2004), 59–76; Gibbs, 99–100; Holt, 112–24; McEvoy and McGuire, 333–34.</ref>

Responding to [[Baron d'Holbach]]'s ''[[The System of Nature|Système de la Nature]]'' (1770) and [[David Hume]]'s ''[[Dialogues Concerning Natural Religion]]'' (1779) as well as the works of the French ''philosophers'', Priestley maintained that materialism and determinism could be reconciled with a belief in God. He criticised those whose faith was shaped by books and fashion, drawing an analogy between the scepticism of educated men and the credulity of the masses.<ref>Tapper, 320; Priestley, ''Autobiography'', 111; Schofield (2004), 37–42; Holt, 93–94, 139–42.</ref>

Maintaining that humans had no [[free will]], Priestley argued that what he called "philosophical necessity" (akin to absolute determinism) is consonant with Christianity, a position based on his understanding of the natural world. Like the rest of nature, man's mind is subject to the laws of causation, Priestley contended, but because a benevolent God created these laws, the world and the people in it will eventually be perfected. Evil is therefore only an imperfect understanding of the world.<ref>Schofield (2004), 77–91; Garrett, 55; Tapper, 319; Sheps, 138; McEvoy (1983), 50; McEvoy and McGuire, 338–40.</ref>

Although Priestley's philosophical work has been characterised as "audacious and original",<ref name=Tap314/><ref>Sheps, 138.</ref> it partakes of older philosophical traditions on the problems of free will, determinism, and materialism.<ref name="MM341">McEvoy and McGuire, 341–45.</ref> For example, the 17th-century philosopher [[Baruch Spinoza]] argued for absolute determinism and absolute materialism.<ref>Leibniz, Gottfried Wilhelm. ''Confessio Philosophi: Papers Concerning the Problem of Evil, 1671–1678''. Trans. Robert C. Sleigh, Jr. New Haven: Yale University Press (2004), xxxviii, 109. {{ISBN|978-0-300-08958-5}}. The [[s:la:Confessio philosophi|original Latin text]] and an [[s:Confessio philosophi|English translation]] of [[Gottfried Wilhelm Leibniz|Leibniz]]'s ''A Philosopher's Creed'' can be found on the Latin and English Wikisources, respectively.</ref> Like Spinoza<ref>
Stewart, Matthew. ''The Courtier and the Heretic: Leibniz, Spinoza, and the Fate of God in the Modern World''. New York: W. W. Norton (2006), 171. {{ISBN|0-393-05898-0}}.</ref> and Priestley,<ref>McEvoy and McGuire, 341.</ref>
[[Gottfried Wilhelm Leibniz|Leibniz]] argued that human will was completely determined by natural laws;<ref name="adams_1998">
Adams, Robert Merrihew. ''Leibniz: Determinist, Theist, Idealist''. New York: Oxford University Press (1998), 10–13, 1–20, 41–44. {{ISBN|0-19-508460-8}}.</ref>
unlike them, Leibniz argued for a "parallel universe" of immaterial objects (such as human souls) so arranged by God that its outcomes agree exactly with those of the material universe.<ref>
Rutherford, 213–18.</ref>
Leibniz<ref>
Rutherford, 46.</ref>
and Priestley<ref>
Schofield (2004), 78–79.</ref>
share an optimism that God has chosen the chain of events benevolently; however, Priestley believed that the events were leading to a glorious millennial conclusion,<ref name=Tap314/> whereas for Leibniz the entire chain of events was optimal in and of itself, as compared with other conceivable chains of events.<ref>
Rutherford, 12–15, 22–45, 49–54.</ref>

===Founder of British Unitarianism===
{{See also|History of Unitarianism}}
When Priestley's friend [[Theophilus Lindsey]] decided to found a new Christian denomination that would not restrict its members' beliefs, Priestley and others hurried to his aid. On 17 April 1774, Lindsey held the first [[Unitarianism|Unitarian]] service in Britain, at the newly formed [[Essex Street Chapel]] in London; he had even designed his own liturgy, of which many were critical. Priestley defended his friend in the pamphlet ''Letter to a Layman, on the Subject of the Rev. Mr. Lindsey's Proposal for a Reformed English Church'' (1774),<ref>Priestley, Joseph. ''Letter to a Layman, on the Subject of the Rev. Mr. Lindsey's Proposal for a Reformed English Church''. London: Printed for J. Wilkie, 1774.</ref> claiming that only the form of worship had been altered, not its substance, and attacking those who followed religion as a fashion. Priestley attended Lindsey's church regularly in the 1770s and occasionally preached there.<ref>Schofield (2004), 26–28; Jackson, 124; Gibbs, 88–89; Holt, 56–64.</ref> He continued to support institutionalised Unitarianism for the rest of his life, writing several ''Defenses'' of Unitarianism and encouraging the foundation of new Unitarian chapels throughout Britain and the United States.<ref>Schofield (2004), 225, 236–38.</ref>

[[File:Priestley Joseph pneumatic trough.jpg|thumb|Equipment used by Priestley in his experiments on gases, 1775|alt=Engraving of assorted scientific equipment, such as a pneumatic trough. A dead mouse rests under one glass canister.]]
[[File:Priestly-2.jpg|alt=Title page to volume I of Experiments and Observations on Different Kinds of Air (1774)|thumb|upright|Title page to volume I of ''Experiments and Observations on Different Kinds of Air'' (1774)]]

===Experiments and Observations on Different Kinds of Air===
{{see also|Wikisource:An Inventory of the Furniture in Dr. Priestley's Study}}

Priestley's years in Calne were the only ones in his life dominated by scientific investigations; they were also the most scientifically fruitful. His experiments were almost entirely confined to "airs", and out of this work emerged his most important scientific texts: the six volumes of ''[[Experiments and Observations on Different Kinds of Air]]'' (1774–86).<ref>Priestley, Joseph. ''[[Experiments and Observations on Different Kinds of Air]]''. 3 vols. London W. Bowyer and J. Nichols, 1774–77. There are several different editions of these volumes, each important.</ref><ref>See Gibbs 67–83 for a description of all of Priestley's experiments during this time; Thorpe, 170ff.</ref> These experiments helped repudiate the last vestiges of the [[Classical element|theory of four elements]], which Priestley attempted to replace with his own variation of [[phlogiston theory]]. According to that 18th-century theory, the combustion or [[redox|oxidation]] of a substance corresponded to the release of a material substance, ''phlogiston''.<ref>Thorpe, 167–68; Schofield (2004), 98–101.</ref>

Priestley's work on "airs" is not easily classified. As historian of science [[Simon Schaffer]] writes, it "has been seen as a branch of physics, or chemistry, or natural philosophy, or some highly idiosyncratic version of Priestley's own invention".<ref>Schaffer, 152.</ref> Furthermore, the volumes were both a scientific and a political enterprise for Priestley, in which he argues that science could destroy "undue and usurped authority" and that government has "reason to tremble even at an air pump or an electrical machine".<ref>Qtd. in Kramnick, 11–12; see also Schofield (2004), 121–24.</ref>

Volume I of ''Experiments and Observations on Different Kinds of Air'' outlined several discoveries: "nitrous air" ([[nitric oxide]], NO); "vapor of spirit of salt", later called "acid air" or "marine acid air" ([[anhydrous hydrochloric acid]], HCl); "alkaline air" ([[ammonia]], NH<sub>3</sub>); "diminished" or "dephlogisticated nitrous air" ([[nitrous oxide]], N<sub>2</sub>O); and, most famously, "dephlogisticated air" ([[oxygen]], O<sub>2</sub>) as well as experimental findings that showed plants revitalised enclosed volumes of air, a discovery that would eventually lead to the discovery of [[photosynthesis]] by [[Jan Ingenhousz]]. Priestley also developed a "nitrous air test" to determine the "goodness of air". Using a [[pneumatic trough]], he would mix nitrous air with a test sample, over water or mercury, and measure the decrease in volume—the principle of [[eudiometer|eudiometry]].<ref name="Fruton">Fruton, 20, 29</ref> After a small history of the study of airs, he explained his own experiments in an open and sincere style. As an early biographer writes, "whatever he knows or thinks he tells: doubts, perplexities, blunders are set down with the most refreshing candour."<ref>Schofield (2004), 98; Thorpe, 171.</ref> Priestley also described his cheap and easy-to-assemble experimental apparatus; his colleagues therefore believed that they could easily reproduce his experiments.<ref>Schofield (1997), 259–69; Jackson, 110–14; Thorpe, 76–77, 178–79; Uglow, 229–39.</ref> Faced with inconsistent experimental results, Priestley employed phlogiston theory. This led him to conclude that there were only three types of "air": "fixed", "alkaline", and "acid". Priestley dismissed the [[History of chemistry#17th and 18th centuries: Early chemistry|burgeoning chemistry]] of his day. Instead, he focused on gases and "changes in their sensible properties", as had natural philosophers before him. He isolated [[carbon monoxide]] (CO), but apparently did not realise that it was a separate "air".<ref>Schofield (2004), 93–105; Uglow, 240–41; see Gibbs 105–16 for a description of these experiments.</ref>

====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>

==Birmingham (1780–1791)==
In 1780 the Priestleys moved to Birmingham and spent a happy decade surrounded by old friends, until they were forced to flee in 1791 by religiously motivated mob violence in what became known as the [[Priestley Riots]]. Priestley accepted the ministerial position at New Meeting on the condition that he be required to preach and teach only on Sundays, so that he would have time for his writing and scientific experiments. As in Leeds, Priestley established classes for the youth of his parish and by 1781, he was teaching 150 students. Because Priestley's New Meeting salary was only 100 [[Guinea (British coin)|guineas]], friends and patrons donated money and goods to help continue his investigations.<ref>Schofield (2004), 147–50, 196–99, 242–46. Gibbs, 134–40, 169; Uglow, 310–20, 407; Jackson, 227–28; Holt, 132–33.</ref> He was elected a Foreign Honorary Member of the [[American Academy of Arts and Sciences]] in 1782.<ref name=AAAS>{{cite web |title=Book of Members, 1780–2010: Chapter P |url=http://www.amacad.org/publications/BookofMembers/ChapterP.pdf |publisher=American Academy of Arts and Sciences |access-date=28 July 2014 |url-status=live |archive-url=https://web.archive.org/web/20110515183157/http://www.amacad.org/publications/BookofMembers/ChapterP.pdf |archive-date=15 May 2011}}</ref>

===Chemical Revolution===
{{See also|Chemical Revolution}}

[[File:Lunar Society Moonstones 22 Priestley.jpg|thumb|upright|One of a set of [[Lunar Society Moonstones]] commemorating Priestley at [[Great Barr]], Birmingham]]

Many of the friends that Priestley made in Birmingham were members of the [[Lunar Society]], a group of manufacturers, inventors, and natural philosophers who assembled monthly to discuss their work. The core of the group included men such as the manufacturer [[Matthew Boulton]], the chemist and geologist [[James Keir]], the inventor and engineer [[James Watt]], and the botanist, chemist, and geologist [[William Withering]]. Priestley was asked to join this unique society and contributed much to the work of its members.<ref>Schofield (2004), 151–52; for an analysis of Priestley's contributions to each man's work, see Schofield's chapter "Science and the Lunar Society"; see also Jackson, 200–01; Gibbs, 141–47; Thorpe, 93–102; Holt, 127–32; Uglow, 349–50; for a history of the Lunar Society, see Uglow.</ref> As a result of this stimulating intellectual environment, he published several important scientific papers, including "Experiments relating to Phlogiston, and the seeming Conversion of Water into Air" (1783). The first part attempts to refute Lavoisier's challenges to his work on oxygen; the second part describes how steam is "converted" into air. After several variations of the experiment, with different substances as fuel and several different collecting apparatuses (which produced different results), he concluded that air could travel through more substances than previously surmised, a conclusion "contrary to all the known principles of hydrostatics".<ref>Qtd. in Schofield (2004), 167</ref> This discovery, along with his earlier work on what would later be recognised as gaseous diffusion<!-- [[gaseous diffusion]] page seems like an incorrect link -->, would eventually lead [[John Dalton]] and [[Thomas Graham (chemist)|Thomas Graham]] to formulate the [[kinetic theory of gases]].<ref>Schofield (2004), 168; see also Jackson 203–08; Gibbs, 154–61; Uglow, 358–61.</ref>

In 1777, [[Antoine Lavoisier]] had written ''Mémoire sur la combustion en général'', the first of what proved to be a series of attacks on phlogiston theory;<ref>''Memoirs of the Royal Academy of Sciences of Paris'' année 1777 (1780): 592–600. The next, most notable installment was "Réflexions sur le phlogistique, pour servir de suite à la théorie de la combustion et de la calcination publiée en 1777" ''Memoirs of the Royal Academy of Sciences of Paris'' année 1783 (1786): 505–538 (translated by Nicholas W. Best as "[https://link.springer.com/article/10.1007/s10698-015-9220-5 Lavoisier's 'Reflections on Phlogiston' I: Against Phlogiston Theory"], ''[[Foundations of Chemistry]]'' 17 (2015): 137–151).</ref> it was against these attacks that Priestley responded in 1783. While Priestley accepted parts of Lavoisier's theory, he was unprepared to assent to the major revolutions Lavoisier proposed: the overthrow of phlogiston, a chemistry based conceptually on [[Chemical element|elements]] and [[Chemical compound|compounds]], and a new [[International Union of Pure and Applied Chemistry nomenclature|chemical nomenclature]]. Priestley's original experiments on "dephlogisticated air" (oxygen), combustion, and water provided Lavoisier with the data he needed to construct much of his system; yet Priestley never accepted Lavoisier's new theories and continued to defend phlogiston theory for the rest of his life. Lavoisier's system was based largely on the ''quantitative'' concept that [[mass]] is neither created nor destroyed in chemical reactions (i.e., the [[conservation of mass]]). By contrast, Priestley preferred to observe ''qualitative'' changes in heat, colour, and particularly volume. His experiments tested "airs" for "their solubility in water, their power of supporting or extinguishing flame, whether they were respirable, how they behaved with acid and alkaline air, and with nitric oxide and inflammable air, and lastly how they were affected by the [[electric spark]]."<ref>Thorpe, 210; see also Schofield (2004), 169–94; Jackson 216–24.</ref>

[[File:David - Portrait of Monsieur Lavoisier and His Wife.jpg|thumb|upright=0.9|left|[[Antoine Lavoisier]] and his wife, [[Marie-Anne Pierrette Paulze]], by [[Jacques-Louis David]], 1788|alt=Full-length portraits of a man and a woman. The man is seated at a table covered with a bright red cloth, looking up at the woman, and she is looking out at the viewer. They occupy the bottom half of the painting, while the top half resembles marble and pillars. She is wearing a white dress with a blue sash and he is wearing a dark coloured suit. Glass chemistry equipment sits on the table and on the floor.]]

By 1789, when Lavoisier published his ''[[Traité Élémentaire de Chimie]]'' and founded the ''[[Annales de Chimie]]'', the new chemistry had come into its own. Priestley published several more scientific papers in Birmingham, the majority attempting to refute Lavoisier. Priestley and other Lunar Society members argued that the new French system was too expensive, too difficult to test, and unnecessarily complex. Priestley in particular rejected its "establishment" aura. In the end, Lavoisier's view prevailed: his new chemistry introduced many of the principles on which [[chemistry|modern chemistry]] is founded.<ref>Schaffer, 164; Uglow, 356; McEvoy (1983), 56–57; Donovan, 175–76, 180–81.</ref>

Priestley's refusal to accept Lavoisier's "new chemistry"—such as the conservation of mass—and his determination to adhere to a less satisfactory theory has perplexed many scholars.<ref>See Schaffer, 162–70 for a historiographical analysis.</ref> Schofield explains it thus: "Priestley was never a chemist; in a modern, and even a Lavoisierian, sense, he was never a scientist. He was a natural philosopher, concerned with the economy of nature and obsessed with an idea of unity, in theology and in nature."<ref>Schofield (2004), 194.</ref> Historian of science John McEvoy largely agrees, writing that Priestley's view of nature as coextensive with God and thus infinite, which encouraged him to focus on facts over hypotheses and theories, prompted him to reject Lavoisier's system.<ref>McEvoy (1983), 51ff.</ref> McEvoy argues that "Priestley's isolated and lonely opposition to the oxygen theory was a measure of his passionate concern for the principles of intellectual freedom, epistemic equality and critical inquiry."<ref>McEvoy (1983), 57; see also McEvoy and MeGuire 395ff.</ref> Priestley himself claimed in the last volume of ''Experiments and Observations'' that his most valuable works were his theological ones because they were "superior [in] dignity and importance".<ref>Qtd. in Thorpe, 213.</ref>

===Defender of English Dissenters and French revolutionaries===
{{further|Joseph Priestley and Dissent|Commons:Joseph Priestley Cartoons}}

[[File:PriestleyCartoon.jpg|thumb|upright|''DOCTOR PHLOGISTON, The PRIESTLEY politician or the Political Priest'': An anti-Priestley cartoon shows him trampling on the Bible and burning documents representing English freedom. "Essays on Matter and Spirit", "Gunpowder", and "Revolution Toasts" bulge from his pockets.|alt=Caricature of man in frock coat and wig trampling on sacred documents and burning others.]]

Although Priestley spent much of this time defending phlogiston theory from the "new chemists", most of what he published in Birmingham was theological. For example, in 1782, he published the fourth volume of his ''Institutes'', ''[[An History of the Corruptions of Christianity]]'', describing how he thought the teachings of the early Christian church had been "corrupted" or distorted.<ref>Priestley, Joseph. ''[[An History of the Corruptions of Christianity]]''. 2 vols. Birmingham: Printed by Piercy and Jones; London: Printed for J. Johnson, 1782.</ref> Schofield describes the work as "derivative, disorganized, wordy, and repetitive, detailed, exhaustive, and devastatingly argued".<ref>Schofield (2004), 216.</ref> The text addresses issues ranging from the divinity of Christ to the proper form for the Lord's Supper. In 1786, Priestley published its provocatively titled sequel, ''An History of Early Opinions concerning Jesus Christ, compiled from Original Writers, proving that the Christian Church was at first Unitarian''. [[Thomas Jefferson]] later wrote of the profound effect that these two books had on him: "I have read his Corruptions of Christianity, and Early Opinions of Jesus, over and over again; and I rest on them&nbsp;... as the basis of my own faith. These writings have never been answered."<ref>Qtd. in Gibbs, 249.</ref> Although a few readers such as Jefferson and other Rational Dissenters approved of the work, many others reviewed it harshly because of its extreme theological positions, particularly its rejection of the [[Trinity]].<ref>Schofield (2004), 216–23; Thorpe, 106–08; Holt, 133–39; Philip (1985).</ref>

In 1785, while Priestley was engaged in a pamphlet war over ''Corruptions'', he also published ''The Importance and Extent of Free Enquiry'', claiming that the [[Protestant Reformation|Reformation]] had not really reformed the church.<ref>Priestley, Joseph. ''The importance and extent of free inquiry in matters of religion: a sermon, preached before the congregations of the Old and New Meeting of Protestant Dissenters at Birmingham. 5 November 1785. To which are added, reflections on the present state of free inquiry in this country''. Birmingham: Printed by M. Swinney; for J. Johnson, London, 1785.</ref> In words that would boil over into a national debate, he challenged his readers to enact change:
<blockquote>
Let us not, therefore, be discouraged, though, for the present, we should see no great number of churches professedly unitarian&nbsp;.... We are, as it were, laying gunpowder, grain by grain, under the old building of error and superstition, which a single spark may hereafter inflame, so as to produce an instantaneous explosion; in consequence of which that edifice, the erection of which has been the work of ages, may be overturned in a moment, and so effectually as that the same foundation can never be built upon again&nbsp;....<ref>Qtd. in Gibbs, 173.</ref>
</blockquote>
Although discouraged by friends from using such inflammatory language, Priestley refused to back down from his opinions in print and he included it, forever branding himself as "Gunpowder Joe". After the publication of this seeming call for revolution in the midst of the [[French Revolution]], pamphleteers stepped up their attacks on Priestley and he and his church were even threatened with legal action.<ref>Gibbs, 169–76; Uglow, 408.</ref>

[[File:A Word of Comfort2.jpg|left|thumb|"A Word of Comfort" by [[William Dent (cartoonist)|William Dent]] (dated 22 March 1790). Priestley is preaching in front of [[Charles James Fox]] who asks "Pray, Doctor, is there such a thing as a Devil?", to which Priestley responds "No" while the devil prepares to attack Priestley from behind.|alt=Caricature of a man preaching out of a barrel labelled "Fanaticism", stacked up on books labelled "Priestley's works" to a crowd, while the devil sneaks up on him.]]
In 1787, 1789, and 1790, Dissenters again tried to repeal the [[Test Act|Test]] and [[Corporation Act 1661|Corporation Acts]]. Although they might have succeeded initially, by 1790, with the fears of revolution looming in Parliament, few were swayed by appeals to equal rights. Political cartoons, one of the most effective and popular media of the time, skewered the Dissenters and Priestley.<ref>Gibbs, 176–83.</ref> In Parliament, [[William Pitt the Younger|William Pitt]] and [[Edmund Burke]] argued against the repeal, a betrayal that angered Priestley and his friends, who had expected the two men's support. Priestley wrote a series of ''Letters to William Pitt''<ref>Priestley, Joseph. ''A letter to the Right Honourable William Pitt,&nbsp;... on the subjects of toleration and church establishments; occasioned by his speech against the repeal of the Test and Corporation Acts, on Wednesday 28 March 1787''. London: Printed for J. Johnson and J. Debrett, 1787.</ref> and ''Letters to Burke''.<ref>Priestley, Joseph. ''Letters to the Right Honourable Edmund Burke, occasioned by his Reflections on the Revolution in France, &c.'' Birmingham: Printed by Thomas Pearson; sold by J. Johnson, London, 1791.</ref>

Dissenters such as Priestley who supported the French Revolution came under increasing suspicion as scepticism regarding the revolution grew.<ref>Schofield (2004), 269–81; Thorpe, 122–25; Uglow, 409, 435–38; Holt, 142ff; Philip (1985).</ref> In its propaganda against "[[Radicals (UK)|radicals]]", Pitt's administration used the "gunpowder" statement to argue that Priestley and other Dissenters wanted to overthrow the government. Burke, in his famous ''[[Reflections on the Revolution in France]]'' (1790), tied natural philosophers, and specifically Priestley, to the French Revolution, writing that radicals who supported science in Britain "considered man in their experiments no more than they do mice in an air pump".<ref>Qtd. in Crossland, 294.</ref> Burke also associated [[republicanism|republican]] principles with alchemy and insubstantial air, mocking the scientific work done by both Priestley and French chemists. He made much in his later writings of the connections between "Gunpowder Joe", science, and Lavoisier—who was improving gunpowder for the French in their [[French Revolutionary Wars|war against Britain]].<ref>Crossland, 283–87, 305.</ref> Paradoxically, a secular statesman, Burke, argued against science and maintained that religion should be the basis of civil society, whereas a Dissenting minister, Priestley, argued that religion could not provide the basis for civil society and should be restricted to one's private life.<ref>Kramnick, 22.</ref>

Priestley also supported the campaign to abolish the British [[Atlantic slave trade#British abolitionism|slave trade]] and published a sermon in 1788 in which he declared that nobody treated enslaved people "with so much cruelty as the English".<ref>{{Cite journal |last=Page |first=Anthony |date=2011 |title=Rational dissent, enlightenment and abolition of the British slave trade |url=https://www.cambridge.org/core/journals/historical-journal/article/abs/rational-dissent-enlightenment-and-abolition-of-the-british-slave-trade/B5A511D6D776378EFF643B300E3DD3E2 |journal=The Historical Journal |volume=54 |issue=3 |pages=748–49 |doi=10.1017/S0018246X11000227 |s2cid=145068908}}</ref>

===Birmingham riots of 1791===
{{main|Priestley Riots}}
[[File:Priestley Riots painting.jpg|thumb|The attack on Priestley's home, Fairhill, [[Sparkbrook]], Birmingham|alt=Burning three-story house, surrounded by a mob. People are throwing things out of the windows and belongings are scattered on the street.]]

The animus that had been building against Dissenters and supporters of the American and French Revolutions exploded in July 1791. Priestley and several other Dissenters had arranged to have a celebratory dinner on [[Bastille Day]], the anniversary of the [[storming of the Bastille]], a provocative action in a country where many disapproved of the French Revolution and feared that it might spread to Britain. Amid fears of violence, Priestley was convinced by his friends not to attend. Rioters gathered outside the hotel during the banquet and attacked the attendees as they left. The rioters moved on to the New Meeting and Old Meeting churches, and burned both to the ground. Priestley and his wife fled from their home; although their son William and others stayed behind to protect their property, the mob overcame them and torched Priestley's house "Fairhill" at [[Sparkbrook]], destroying his valuable laboratory and all of the family's belongings. Twenty-six other Dissenters' homes and three more churches were burned in the three-day riot.<ref name=Dionisio>{{cite journal |last1=Dionisio |first1=Jennifer |title=Birmingham Toast |journal=Chemical Heritage Magazine |date=Summer 2010 |volume=28 |issue=2 |page=18 |url=https://www.sciencehistory.org/distillations/magazine/birmingham-toast}}</ref> Priestley spent several days hiding with friends until he was able to travel safely to London. The carefully executed attacks of the "mob" and the farcical trials of only a handful of the "leaders" convinced many at the time—and modern historians later—that the attacks were planned and condoned by local Birmingham [[Magistrate#United Kingdom|magistrates]]. When [[George III]] was eventually forced to send troops to the area, he said: "I cannot but feel better pleased that Priestley is the sufferer for the doctrines he and his party have instilled, and that the people see them in their true light."<ref>Qtd. in Gibbs, 204; Schofield (2004), 264, 285, 289; Thorpe, 122–44; Uglow, 440–46; Jackson, 248–60; Rose, 68–88; Holt, 154ff.</ref>

==Hackney (1791–1794)==
{{quote box|bgcolor=#c6dbf7|width=30%|quote=<poem>
... Lo! Priestley there, patriot, and saint, and sage,
Him, full of years, from his loved native land
Statesmen blood-stained and priests idolatrous
By dark lies maddening the blind multitude
Drove with vain hate&nbsp;....
</poem>|source=From "Religious Musings" (1796) by [[Samuel Taylor Coleridge]]<ref>{{cite news |author=Coleridge, Samuel Taylor |url=https://www.usask.ca/english/barbauld/related_texts/religious_musings.html |title=Religious Musings: A Desultory Poem, Written on the Christmas Eve of 1794 |access-date=1 January 2010 |author-link=Samuel Taylor Coleridge |url-status=live |archive-url=https://web.archive.org/web/20100112095555/http://www.usask.ca/english/barbauld/related_texts/religious_musings.html |archive-date=12 January 2010 |df=dmy-all}}</ref>}}

Unable to return to Birmingham, the Priestleys eventually settled in [[Lower Clapton]], a district in [[Hackney (parish)|Hackney]], [[Middlesex]]<ref>
{{cite web |url=http://www.hackney.gov.uk/ep-joseph-priestley.htm |title=Joseph Priestley at hackney.gov.uk |access-date=11 June 2010 |archive-url=https://web.archive.org/web/20160303205157/http://www.hackney.gov.uk/ep-joseph-priestley.htm |archive-date=3 March 2016 |url-status=dead}} 
</ref> where he gave a series of lectures on history and natural philosophy at the [[Dissenting academies|Dissenting academy]], the [[New College at Hackney]]. Friends helped the couple rebuild their lives, contributing money, books, and laboratory equipment. Priestley tried to obtain restitution from the government for the destruction of his Birmingham property, but he was never fully reimbursed.<ref>Schaffer, 160; Schofield (2004), 298–99; Thorpe, 145–46; Uglow, 446–49; Jackson, 300–05.</ref> He also published ''An Appeal to the Public on the Subject of the Riots in Birmingham'' (1791),<ref>Priestley, Joseph. ''An Appeal to the Public on the Subject of the Riots in Birmingham. To which are added, strictures on a pamphlet, entitled 'Thoughts on the late riot at Birmingham.{{'}}'' Birmingham: Printed by J. Thompson; sold by J. Johnson, London, 1791.</ref> which indicted the people of Birmingham for allowing the riots to occur and for "violating the principles of English government".<ref>Qtd. in Schofield (2004), 295.</ref>

The couple's friends urged them to leave Britain and emigrate to either France or the new United States, even though Priestley had received an appointment to preach for the [[Gravel Pit Meeting]] congregation.<ref>
A [[blue plaque]] marks the site of the Gravel Pit Meeting at Ram Place and a brown plaque the site of the Priestleys' house at 113, Lower Clapton Road: [http://www.hackney.gov.uk/ep-joseph-priestley.htm Joseph Priestley at hackney.gov.uk] {{Webarchive|url=https://web.archive.org/web/20160303205157/http://www.hackney.gov.uk/ep-joseph-priestley.htm |date=3 March 2016 }} 
</ref> Priestley was minister between 1793 and 1794 and the sermons he preached there, particularly the two [[Fasting|Fast]] Sermons, reflect his growing [[millenarianism]], his belief that the end of the world was fast approaching. After comparing Biblical prophecies to recent history, Priestley concluded that the [[French Revolution]] was a harbinger of the [[Second Coming|Second Coming of Christ]]. Priestley's works had always had a millennial cast, but after the beginning of the French Revolution, this strain increased.<ref>Garrett, 53, 57, 61.</ref> He wrote to a younger friend that while he himself would not see the Second Coming, his friend "may probably live to see it&nbsp;... It cannot, I think be more than twenty years [away]."<ref>Qtd. in Garrett, 62.</ref>

{{multiple image
| perrow            = 2/1
| total_width       = 360
| caption_align     = center
| align             = right
| image_style       = border:none;
| image1            = Friends of the People 1792 Cruikshank.jpg
| image2            = James Gillray 1793 Dumourier Dining in State at St James P.933.53.11.jpg
| footer            = {{font|size=100%|font=Sans-serif|text=Left: ''The Friends of the People'', 15 November 1792, caricaturing Joseph Priestley and [[Thomas Paine]] ([[Science History Institute]]). Right: ''Dumourier Dining in State at St James's, on 15 May 1793'' by [[James Gillray]]: Priestley bears a mitre-crowned pie, as he, [[Charles James Fox]] and [[Richard Brinsley Sheridan]] serve the French general [[Charles François Dumouriez]].<ref name=Bowden>{{cite book |editor-last1=Bowden |editor-first1=Mary Ellen |editor-last2=Rosner |editor-first2=Lisa |title=Joseph Priestley, radical thinker : a catalogue to accompany the exhibit at the Chemical Heritage Foundation commemorating the 200th anniversary of the death of Joseph Priestley, 23 August 2004 to 29 July 2005 |date=2005 |publisher=Chemical Heritage Foundation |location=Philadelphia, Penns. |isbn=978-0941901383 |page=26 |url=https://books.google.com/books?id=JwjrZ8qygeEC&pg=PA26 |access-date=11 September 2014 |url-status=live |archive-url=https://web.archive.org/web/20160602214345/https://books.google.com/books?id=JwjrZ8qygeEC&pg=PA26 |archive-date=2 June 2016}}</ref>}}
}}

Daily life became more difficult for the family: Priestley was burned in effigy along with [[Thomas Paine]]; vicious political cartoons continued to be published about him; letters were sent to him from across the country, comparing him to the devil and [[Guy Fawkes]]; tradespeople feared the family's business; and Priestley's Royal Academy friends distanced themselves. As the penalties became harsher for those who spoke out against the government, Priestley examined options for removing himself and his family from England.{{citation needed|date=March 2021}}

Joseph Priestley's son William was presented to the French Assembly and granted letters of naturalisation on 8 June 1792.<ref>Schofield (2004), p. 318.</ref> Priestley learned about it from the ''Morning Chronicle''.<ref>Gibbs (1965), p. 214.</ref> A decree of 26 August 1792 by the French National Assembly conferred French citizenship on Joseph Priestley and others who had "served the cause of liberty" by their writings.<ref>Gibbs (1965), p. 216; Schofield (2004), p. 318.</ref> Priestley accepted French citizenship, considering it "the greatest of honours".<ref>Graham (1995), p. 26.</ref> In the [[1792 French National Convention election|French National Convention election]] on 5 September 1792, Joseph Priestley was elected to the French [[National Convention]] by at least two departments, ([[Orne]] and [[Rhône-et-Loire]]).<ref>Gibbs (1965), p. 216; Schofield,(2004), p. 318.</ref> He declined the honour, on the grounds that he was not fluent in French.<ref name=Schwartz>{{cite book |editor-last1=Schwartz |editor-first1=A. Truman |editor-last2=McEvoy |editor-first2=John G. |title=Motion toward perfection : the achievement of Joseph Priestley |date=1990 |publisher=Skinner House Books |location=Boston, Mass. |isbn=978-1558960107 |page=199 |url=https://books.google.com/books?id=Sm-OvY1FV30C&pg=PA199 |access-date=11 September 2014 |url-status=live |archive-url=https://web.archive.org/web/20160603173752/https://books.google.com/books?id=Sm-OvY1FV30C&pg=PA199 |archive-date=3 June 2016}}</ref>

As relations between England and France worsened, a removal to France became impracticable.<ref>Graham (1995), p. 27; Schofield (2004), p. 318.</ref> Following the declaration of war of February 1793, and the Aliens Bill of March 1793, which forbade correspondence or travel between England and France, William Priestley left France for America. Joseph Priestley's sons Harry and Joseph chose to leave England for America in August 1793.<ref>Graham (1995), p. 33.</ref> Finally Priestley himself followed with his wife, boarding the ''Sansom'' at Gravesend on 7 April 1794.<ref>Graham (1995), p. 35.</ref> Five weeks after Priestley left, William Pitt's administration began arresting radicals for [[seditious libel]], resulting in the famous [[1794 Treason Trials]].<ref>Gibbs, 207–22; Schofield (2004), 304–18; Thorpe, 145–55; Uglow, 446–49, 453–54; Jackson, 300–05; Holt, 177–78.</ref>

==Pennsylvania (1794–1804)==
{{see also|Joseph Priestley House}}

[[File:Priestley.jpg|thumb|Portrait of Joseph Priestley by [[Ellen Sharples]] ({{Circa|1794-97}})]]

[[File:Priestley House Front 2.jpg|thumb|alt=Photograph of a two-story, white clapboard house|The Priestleys' rural Pennsylvania home never became the centre of a [[utopia]]n community, as the expected emigrants could not afford the journey.<ref>Schofield (2004), 329–30.</ref>]]

The Priestleys arrived in New York City on 4 June 1794, where they were [[wikt:fête|fêted]] by various political factions vying for Priestley's endorsement. Priestley declined their entreaties, hoping to avoid political discord in his new country. Before travelling to a new home in the backwoods of [[Northumberland County, Pennsylvania]], at Point township (now the [[Northumberland, Pennsylvania|Borough of Northumberland]]), Priestley and his wife lodged in [[Philadelphia]], where he gave a series of sermons which led to the founding of the [[First Unitarian Church of Philadelphia]]. Priestley turned down an opportunity to teach chemistry at the [[University of Pennsylvania]].<ref>Schofield (2004), 324–32; Thorpe, 155–57; Jackson, 310–14; Holt, 179ff.</ref>

Priestley's son Joseph Priestley Jr. was a leading member of a consortium that had purchased {{Convert|300000|acre|ha}} of virgin woodland between the forks of [[Loyalsock Creek]]. This they intended to lease or sell in {{Convert|400|acre|ha|abbr=out|adj=on}} plots, with payment deferred to seven annual instalments, with interest.<ref>Mary Cathryne Park, ''Joseph Priestley and the problem of Pantisocrasy'' (Philadelphia, 1947), 14–24, 52–57. Penn State University Library, The Joseph Priestley Collection. {{cite web |url=http://www.libraries.psu.edu/psul/digital/priestley.html |title=The Joseph Priestley Collection |access-date=21 June 2013 |url-status=dead |archive-url=https://archive.today/20130624205006/http://www.libraries.psu.edu/psul/digital/priestley.html |archive-date=24 June 2013}} Property inventory assets and debts account book, 1807–1810</ref> His brothers, William and Henry, bought a {{Convert|284|acre|ha|abbr=out|adj=on}} plot of woodland which they attempted to transform into a farm, later called "Fairhill", felling and uprooting trees, and making [[Liming (soil)|lime]] to sweeten the soil by building their own lime kilns.<ref>Tony Rail, "William Priestley vindicated," ''Enlightenment and Dissent'' no. 28 (2012); 150–195. {{cite web |url=http://www.english.qmul.ac.uk/drwilliams/journal/intro.html |title=Dr Williams's Centre for Dissenting Studies |access-date=23 December 2013 |url-status=live |archive-url=https://web.archive.org/web/20131224101831/http://www.english.qmul.ac.uk/drwilliams/journal/intro.html |archive-date=24 December 2013}}</ref> Henry Priestley died 11 December 1795, possibly of [[malaria]] which he may have contracted after landing at New York. Mary Priestley's health, already poor, deteriorated further; although William's wife, Margaret Foulke-Priestley, moved in with the couple to nurse Mary 24 hours a day,<ref>Tony Rail, ''op. cit.'' 161.</ref> Mary Priestley died 17 September 1796.<ref>Rutt, I(ii), 354.</ref> Priestley then moved in with his elder son, Joseph Jr., and his wife Elizabeth Ryland-Priestley.{{citation needed|date=March 2021}} [[Thomas Cooper (American politician, born 1759)|Thomas Cooper]], whose son, Thomas Jr., was living with the Priestleys, was a frequent visitor.{{citation needed|date=March 2021}}

[[File:PriestleyPeale.jpg|thumb|left|upright|alt=Half-length portrait of an elderly man with wispy brown hair. He is wearing a black jacket and a white shirt.|Priestley, painted later in life by [[Rembrandt Peale]] ({{Circa|1800}});<ref>McLachlan (1983), 34.</ref> Americans knew Priestley less as a man of science and more as a defender of the freedom of the colonies and of Dissenters.<ref>Schofield (2004), 326.</ref>]]

Since his arrival in America, Priestley had continued to defend his [[Unitarianism|Christian Unitarian]] beliefs; now, falling increasingly under the influence of Thomas Cooper and Elizabeth Ryland-Priestley, he was unable to avoid becoming embroiled in political controversy. In 1798, when, in response to the [[Charles Cotesworth Pinckney|Pinckney affair]], a belligerent [[John Adams|President Adams]] sought to enlarge the navy and mobilise the militia into what Priestley and Cooper saw as a 'standing army', Priestley published an anonymous newspaper article: ''Maxims of political arithmetic'', which attacked Adams, defended free trade, and advocated a form of Jeffersonian isolationism.<ref>Signed 'A Quaker in politics,' the ''Maxims'' were printed over two days in the ''Aurora General Advertiser'', 26 & 27 February 1798, and reprinted in both the ''Aurora''and ''Carey's United States' Recorder'', 31 March & 1 April 1799. See Rutt, XXV, 175–82.</ref> In the same year, a small package, addressed vaguely: "Dr Priestley in America," was seized by the [[Royal Navy]] on board a neutral Danish boat. It was found to contain three letters, one of which was signed by the radical printer [[John Hurford Stone]]. These intercepted letters were published in London, and copied in numerous papers in America.<ref>''Copies of original letters recently written by persons in Paris to Dr. Priestley in America, taken on board of a neutral vessel'' (London, 1798). ''Federal Gazette'' (Baltimore, MD), 27 August 1798.</ref> One of the letters was addressed to "MBP", with a note: "I inclose a note for our friend MBP—but, as ignorant of the name he bears at present among you, I must beg you to seal and address it." This gave the intercepted letters a tinge of intrigue. Fearful lest they be taken as evidence of him being a 'spy in the interest of France', Priestley sent a clumsy letter to numerous newspaper editors, in which he naively named "MBP" (Member of the British Parliament) as [[Benjamin Vaughan|Mr. Benjamin Vaughan]], who "like me, thought it necessary to leave England, and for some time is said to have assumed a feigned name."<ref>Vaughan had fled to France in May 1794, when [[John Hurford Stone]]'s brother, William, was arrested and found to have a letter from Vaughan. In France, to avoid arrest as an Englishmen, he assumed the name of Jean Martin, and lived quietly at Passy. ([[John Goldworth Alger|John G. Alger]], ''Englishmen in the French Revolution'' (London, 1889), 93).</ref> [[William Cobbett]], in his ''Porcupine's Gazette'', 20 August 1798, added that Priestley "has told us who Mr MBP is, and has confirmed me in the opinion of their both being spies in the interest of France."<ref>Tony Rail, ''op. cit.''; Schofield (2004), 329–38; Gibbs, 234–37; Jackson, 317–18; Garrett, 63; Holt, 199–204.</ref>

Joseph Priestley Jr. left on a visit to England at Christmas 1798, not returning until August 1800. In his absence, his wife Elizabeth Ryland-Priestley and Thomas Cooper became increasing close, collaborating in numerous political essays.<ref>In December 1799, two of Elizabeth Ryland-Priestley's essays, ''On the propriety and expediency of unlimited enquiry'', and ''A Reply to'' [Thomas Cooper's] ''Observations on the Fast Day'' [Cooper had challenged the power of a President to declare a day of fasting and prayer], were published as part of ''Political essays'' (Northumberland, PA, 1799). [Eugene Volokh: "Elizabeth Ryland-Priestley, Early American author on free speech"; ''New York University Journal of Law & Liberty'', 4(2) (2009), 382–85].</ref> Priestley continued to be influenced by Elizabeth and Cooper, even helping hawk a seditious handbill Cooper had printed around [[Northumberland, Pennsylvania|Point township]], and across the [[Susquehanna River|Susquehanna]] at [[Sunbury, Pennsylvania|Sunbury]]. In September 1799, [[William Cobbett]] printed extracts from this handbill, asserting that: "Dr Priestley has taken great pains to circulate this address, has travelled through the country for the purpose, and is in fact the patron of it." He challenged Priestley to "clear himself of the accusation" or face prosecution."<ref>Tony Rail, ''op. cit.'' 166–67.</ref> Barely a month later, in November and December 1799, Priestley stepped forward in his own defence, with his ''Letters to the inhabitants of Northumberland''.<ref>Published in two parts, Northumberland-town PA, 1799; printed by Andrew Kennedy who printed the ''Sunbury and Northumberland Gazette''. A pirate edition seems to have been published at Albany NY for Samuel Campbell of New York. (Robert E Schofield, ''A scientific autobiography of Joseph Priestley'' (Cambridge, MS, 1966), 303).</ref>

[[File:Priestley Graves VIII.jpg|thumb|left|upright|Priestley's original 1804 gravestone in Riverview Cemetery, Northumberland, Pennsylvania; visible at right is part of the new stone, placed in front of it in 1971.]]

Priestley's son, [[William Priestley (Louisiana planter)|William]], now living in Philadelphia, was increasingly embarrassed by his father's actions. He confronted his father, expressing [[John Vaughan (wine merchant)|John]] and Benjamin Vaughan's unease, his own wife's concerns about Elizabeth Ryland-Priestley's dietary care,<ref>Dr Priestley suffered a bilious and bowel condition throughout his adult life, with episodes of severe diarrhoea, for which Margaret Foulke-Priestley seems to have suggested a diet that used maize flour (US Cornmeal), and excluded wheat flour. (Tony Rail, ''op. cit.'' 156, 161).</ref> and his own concerns at the closeness of Elizabeth Ryland-Priestley and Thomas Cooper's relationship, and their adverse influence on Dr Priestley; but this only led to a further estrangement between William and his sister-in-law. When, a while later, Priestley's household suffered a bout of food poisoning, perhaps from [[milk sickness]] or a [[Pathogenic bacteria|bacterial infection]], Elizabeth Ryland-Priestley falsely accused William of having poisoned the family's flour. Although this allegation has attracted the attention of some modern historians, it is believed to be without foundation.<ref>Tony Rail, ''op. cit.''</ref>

Priestley continued the educational projects that had always been important to him, helping to establish the "Northumberland Academy" and donating his library to the fledgling institution. He exchanged letters regarding the proper structure of a university with Thomas Jefferson, who used this advice when founding the [[University of Virginia]]. Jefferson and Priestley became close, and when the latter had completed his ''General History of the Christian Church'',<ref>Priestley, Joseph. ''[https://archive.org/details/ageneralhistory03priegoog A General History of the Christian Church]''. Northumberland: Printed for the author by Andrew Kennedy, 1803.</ref> he dedicated it to President Jefferson, writing that "it is now only that I can say I see nothing to fear from the hand of power, the government under which I live being for the first time truly favourable to me."<ref>Qtd. in Schofield (2004), 339–43.</ref>

Priestley tried to continue his scientific investigations in America with the support of the [[American Philosophical Society]], to which he had been previously elected a member in 1785.<ref>{{cite web |title=APS Member History |url=https://search.amphilsoc.org/memhist/search?creator=joseph%20priestley;smode=advanced |access-date=16 December 2020 |website=search.amphilsoc.org}}</ref> He was hampered by lack of news from Europe; unaware of the latest scientific developments, Priestley was no longer on the forefront of discovery. Although the majority of his publications focused on defending phlogiston theory, he also did some original work on [[spontaneous generation]] and dreams. Despite Priestley's reduced scientific output, his presence stimulated American interest in chemistry.<ref>Schofield (2004), 352–72; Gibbs, 244–46.</ref>

By 1801, Priestley had become so ill that he could no longer write or experiment. He died on the morning of 6 February 1804,<ref>Schofield (2004), 400–01; Gibbs, 247–48; Thorpe, 162–65; Jackson, 324–25; Holt, 213–16.</ref> aged seventy<ref>In accordance with known birth-death dates.  His original headstone gives his age as "LXXI" (71).</ref> and was buried at Riverview Cemetery in [[Northumberland, Pennsylvania]].<ref>For the original marker, see {{cite web |title=Edgar Fahs Smith Collection |url=http://dewey.library.upenn.edu/sceti/smith/PortraitList.cfm?ScientistID=223&visited=smithScientist |access-date=17 November 2006 |url-status=live |archive-url=https://web.archive.org/web/20081223002710/http://dewey.library.upenn.edu/sceti/smith/PortraitList.cfm?ScientistID=223&visited=smithScientist |archive-date=23 December 2008}}

See also page 153 of {{cite journal |author=Walker, William H. |title=History of the Priestley house and the movement for its preservation |journal=Journal of Chemical Education |year=1927 |volume=4 |pages=150–158 |doi=10.1021/ed004p150 |issue=2 |bibcode=1927JChEd...4..150W}}</ref>

Priestley's epitaph reads:

{{blockquote|<poem>
Return unto thy rest, O my soul, for the
Lord hath dealt bountifully with thee.
I will lay me down in peace and sleep till
I awake in the morning of the resurrection.<ref>Qtd. in Schofield (2004), 401.</ref>
</poem>}}

==Degrees==
PRIESTLEY, JOSEPH, LL.D.; University of Edinburgh. Preacher; librarian Earl of Shelbume 1773-80; pastor Unitarian congregation, Birmingham, 1780–91; Gravel
Pit meeting house. Hackney, London, 1791–94; resident Northumberland, Penn,, 1794-1804; discoverer nitric oxide 1772; oxygen, hydrochloric acid and ammonia, 1774; sulphur dioxide and silicon tetrafluoride, 1775; nitrous oxide; member Royal Society 1766; American Philosophical Society; b. Fieldhead, near Leeds, Yorkshire, England, March 24, 1733;  d. Northumberland, Penn., Feb. 6, 1804.<ref>[https://upload.wikimedia.org/wikipedia/commons/b/bc/Historical_catalogue_of_Brown_University%2C_1764-1914_%28IA_catalo00browhistoricalrich%29.pdf Historical Catalogue of Brown University 1764-1914 [Honorary Degree CLass of 1793 p.623]</ref>

==Legacy==
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By the time he died in 1804, Priestley had been made a member of every major scientific society in the Western world and he had discovered numerous substances.<ref>Schofield (2004), 151–52.</ref> The 19th-century French naturalist [[George Cuvier]], in his eulogy of Priestley, praised his discoveries while at the same time lamenting his refusal to abandon phlogiston theory, calling him "the father of modern chemistry [who] never acknowledged his daughter".<ref>Qtd. in McLachlan (1987–90), 259–60.</ref> Priestley published more than 150 works on topics ranging from political philosophy to education to theology to natural philosophy.<ref>Thorpe, 74; Kramnick, 4.</ref> He led and inspired British radicals during the 1790s, paved the way for [[utilitarianism]],<ref name="Tapper, 322">Tapper, 322.</ref> and helped found [[Unitarianism]].<ref>Schofield (2004), 3.</ref> A wide variety of philosophers, scientists, and poets became [[Association of Ideas|associationists]] as a result of his [[redaction]] of David Hartley's ''[[Observations on Man]]'', including [[Erasmus Darwin]], Coleridge, [[William Wordsworth]], [[John Stuart Mill]], [[Alexander Bain (philosopher)|Alexander Bain]], and [[Herbert Spencer]].<ref>Schofield (2004), 52–57; Holt, 111–12.</ref> [[Immanuel Kant]] praised Priestley in his ''[[Critique of Pure Reason]]'' (1781), writing that he "knew how to combine his paradoxical teaching with the interests of religion".<ref name=Tap314/> Indeed, it was Priestley's aim to "put the most 'advanced' Enlightenment ideas into the service of a rationalized though heterodox Christianity, under the guidance of the basic principles of scientific method".<ref name="Tapper, 322"/>

Considering the extent of Priestley's influence, relatively little scholarship has been devoted to him. In the early 20th century, Priestley was most often described as a conservative and dogmatic scientist who was nevertheless a political and religious reformer.<ref>McEvoy (1983), 47.</ref> In a historiographic review essay, historian of science [[Simon Schaffer]] describes the two dominant portraits of Priestley: the first depicts him as "a playful innocent" who stumbled across his discoveries; the second portrays him as innocent as well as "warped" for not understanding their implications better. Assessing Priestley's works as a whole has been difficult for scholars because of his wide-ranging interests. His scientific discoveries have usually been divorced from his theological and metaphysical publications to make an analysis of his life and writings easier, but this approach has been challenged recently by scholars such as John McEvoy and Robert Schofield. Although early Priestley scholarship claimed that his theological and metaphysical works were "distractions" and "obstacles" to his scientific work, scholarship published in the 1960s, 1970s, and 1980s maintained that Priestley's works constituted a unified theory. However, as Schaffer explains, no convincing synthesis of his work has yet been expounded.<ref>Schaffer, 154–57.</ref> More recently, in 2001, historian of science Dan Eshet has argued that efforts to create a "synoptic view" have resulted only in a rationalisation of the contradictions in Priestley's thought, because they have been "organized around philosophical categories" and have "separate[d] the producers of scientific ideas from any social conflict".<ref>Eshet, 131.</ref>

[[File:Blue plaque - Joseph Priestley - New Meeting Street Birmingham - Andy Mabbett.png|thumbnail|A [[blue plaque]] from the [[Royal Society of Chemistry]] commemorates Priestley at New Meeting Street, Birmingham.]]

Priestley has been remembered by the towns in which he served as a reforming educator and minister and by the scientific organisations he influenced. Two educational institutions have been named in his honour—[[Priestley College]] in [[Warrington]] and [[Joseph Priestley College]] in [[City of Leeds|Leeds]]<ref>{{cite web |url=http://www.joseph-priestley.ac.uk/index.php?option=com_content&view=article&id=288&Itemid=115 |title=Joseph Priestley College |archive-url=https://web.archive.org/web/20071114060836/http://www.joseph-priestley.ac.uk/AboutUs/JosephPriestley.htm |archive-date=14 November 2007 |publisher=Joseph Priestley College |access-date=1 January 2010}}</ref> (now part of [[Leeds City College]])—and an asteroid, [[5577 Priestley]], discovered in 1986 by [[Duncan Waldron]].<ref>Schmadel, Lutz D. ''Dictionary of Minor Planet Names''. 5th ed. Berlin and New York: Springer (2003), 474.</ref> In [[Birstall, West Yorkshire|Birstall]], the [[Leeds City Square]], and [[Chamberlain Square|in Birmingham]], he is memorialised through statues,<ref>The statue in Birmingham is a 1951 recast, in bronze, of a white marble original by [[Francis John Williamson]], unveiled on 1 August 1874.</ref> and plaques commemorating him have been posted in Birmingham, [[Calne]] and Warrington.<ref>The [[Lunar Society Moonstones]] honour Priestley in Birmingham. There are [[Blue Plaque]]s commemorating him on the side of the Church of St. Michael and St. Joseph, New Meeting House Lane, Birmingham ([http://www.birminghamcs.org.uk/blueplaques.htm Birmingham Civic Society] {{Webarchive|url=https://web.archive.org/web/20080210082556/http://www.birminghamcs.org.uk/blueplaques.htm |date=10 February 2008 }}   Retrieved 1 January 2010), and another on the Warrington Salvation Army Citadel, once the home of Priestley ([http://img.cryst.bbk.ac.uk/BCA/CNews/1998/Sep98/PLinfo.html British Crystallographic Association] {{webarchive|url=https://web.archive.org/web/20060925103051/http://img.cryst.bbk.ac.uk/BCA/CNews/1998/Sep98/PLinfo.html |date=25 September 2006 }} Retrieved 1 January 2010).</ref> The main undergraduate chemistry laboratories at the [[University of Leeds]] were refurbished as part of a £4m refurbishment plan in 2006 and renamed as the Priestley Laboratories in his honour as a prominent chemist from Leeds.<ref>"[https://www.leeds.ac.uk/news/article/568/minister_opens_4m_state-of-the-art_chemistry_facilities_at_leeds Minister opens £4m 'state-of-the-art' chemistry facilities at Leeds] {{Webarchive|url=https://web.archive.org/web/20210303220943/https://www.leeds.ac.uk/news/article/568/minister_opens_4m_state-of-the-art_chemistry_facilities_at_leeds |date=3 March 2021 }}", 20 October 2006, University of Leeds, Retrieved 25 November 2018.</ref> In 2016 the [[University of Huddersfield]] renamed the building housing its Applied Sciences department as the Joseph Priestley Building, as part of an effort to rename all campus buildings after prominent local figures.<ref>{{cite web |url=https://www.hud.ac.uk/news/2016/april/buildingnamechanges.php |title=University of Huddersfield |website=www.hud.ac.uk |access-date=8 February 2017 |url-status=dead |archive-url=https://web.archive.org/web/20170105084041/https://www.hud.ac.uk/news/2016/april/buildingnamechanges.php |archive-date=5 January 2017}}
</ref>

Since 1952 [[Dickinson College]], Pennsylvania, has presented the Priestley Award to a "distinguished scientist whose work has contributed to the welfare of humanity".<ref>{{cite web |title=Joseph Priestley Award |url=https://www.dickinson.edu/info/20043/about/1973/dickinson_awards/2 |access-date=4 May 2021 |work=[[Dickinson College]]}}</ref> Priestley's work is recognised by a [[National Historic Chemical Landmarks|National Historic Chemical Landmark]] designation for his discovery of oxygen, made on 1 August 1994, at the Priestley House in Northumberland, Penn., by the [[American Chemical Society]]. Similar recognition was made on 7 August 2000, at [[Bowood House]] in Wiltshire, England.<ref>{{cite web |url=http://www.acs.org/content/acs/en/education/whatischemistry/landmarks/josephpriestleyoxygen.html |title=National Historic Chemical Landmarks |date=2000 |website=Joseph Priestley and the Discovery of Oxygen |publisher=American Chemical Society |url-status=live |archive-url=https://web.archive.org/web/20151226182446/http://www.acs.org/content/acs/en/education/whatischemistry/landmarks/josephpriestleyoxygen.html |archive-date=26 December 2015}}</ref> The ACS also awards their highest honour, the [[Priestley Medal]], in his name.<ref>{{cite web |title=85th Anniversary of the Priestley Medal |url=http://pubs.acs.org/cen/priestley/ |work=Chemical & Engineering News |publisher=American Chemical Society |date=7 April 2008 |access-date=12 November 2018 |last=Raber |first=Linda R.}}</ref>

Several of his descendants became physicians, including the noted American surgeon [[James Taggart Priestley|James Taggart Priestley II]] of the [[Mayo Clinic]].<ref>{{cite web |title=Priestley, James Taggart (1903–1979) |website=Plarr's Lives of the Fellows, Royal College of Surgeons of England |url=https://livesonline.rcseng.ac.uk/client/en_GB/lives/search/detailnonmodal/ent:$002f$002fSD_ASSET$002f0$002fSD_ASSET:381038/one?qu=%22rcs%3A+E008855%22&rt=false%7C%7C%7CIDENTIFIER%7C%7C%7CResource+Identifier}}</ref>

== Archives ==
Papers of Joseph Priestley are held at the [[Cadbury Research Library]], University of Birmingham.<ref>{{cite web |title=UoB Calmview5: Search results |url=https://calmview.bham.ac.uk/Record.aspx?src=CalmView.Catalog&id=XJP |access-date=28 January 2021 |website=calmview.bham.ac.uk}}</ref>

==Selected works==
{{Main|List of works by Joseph Priestley}}
{{Library resources box|by=yes|onlinebooksby=yes|viaf=120696744}}
* ''[[The Rudiments of English Grammar]]'' (1761)
* ''[[A Chart of Biography]]'' (1765)
* ''[[Essay on a Course of Liberal Education for Civil and Active Life]]'' (1765)
* ''[[The History and Present State of Electricity]]'' (1767)
* ''[[Essay on the First Principles of Government]]'' (1768)
* ''[[A New Chart of History]]'' (1769)
* ''[[Institutes of Natural and Revealed Religion]]'' (1772–74)
* ''[[Experiments and Observations on Different Kinds of Air]]'' (1774–77)
* ''[[Disquisitions Relating to Matter and Spirit]]'' (1777)
* ''[[The Doctrine of Philosophical Necessity Illustrated]]'' (1777)
* ''[[Letters to a Philosophical Unbeliever]]'' (1780)
* ''[[An History of the Corruptions of Christianity]]'' (1782)
* ''[[Lectures on History and General Policy]]'' (1788)
* ''[[Theological Repository]]'' (1770–73, 1784–88)

==See also==
* [[Bibliography of Benjamin Franklin]]{{snd}}Many works on Franklin make reference to Priestley
* [[List of independent discoveries#Eighteenth century|List of independent discoveries]]
* [[List of liberal theorists]]
* [[Timeline of hydrogen technologies]]

== Citations ==
{{Reflist |30em}}

==Bibliography==
{{refbegin}}
The most exhaustive biography of Priestley is Robert Schofield's two-volume work; several older one-volume treatments exist: those of Gibbs, Holt and Thorpe. Graham and Smith focus on Priestley's life in America and Uglow and Jackson both discuss Priestley's life in the context of other developments in science.

* Gibbs, F. W. ''Joseph Priestley: Adventurer in Science and Champion of Truth''. London: Thomas Nelson and Sons, 1965.
* Graham, Jenny. ''Revolutionary in Exile: The Emigration of Joseph Priestley to America, 1794–1804.'' ''Transactions of the American Philosophical Society'' 85 (1995). {{ISBN|0-87169-852-8}}.
* {{cite book |last=Holt |first=Anne |title=A life of Joseph Priestley |volume= |author-link= |publisher=Westport, Conn., Greenwood Press |year=1970 |orig-year=1931 |isbn=978-0-8371-4240-1 |url=https://archive.org/details/lifeofjosephprie0000holt/page/n5/mode/2up |ref=holt1970}}
* Jackson, Joe. ''A World on Fire: A Heretic, an Aristocrat and the Race to Discover Oxygen''. New York: Viking, 2005. {{ISBN|0-670-03434-7}}.
* {{cite book |last=Isaacson |first=Walter |title=Benjamin Franklin : an American life |author-link=Walter Isaacson |publisher=New York : Simon & Schuster |year=2004 |isbn=978-0-6848-07614 |url=https://archive.org/details/benjaminfranklin0000isaa |ref=isaacson2004}}
* [[Steven Berlin Johnson|Johnson, Steven]]. ''The Invention of Air: A Story of Science, Faith, Revolution, and the Birth of America''. New York: Riverhead, 2008. {{ISBN|1-59448-852-5}}.
* {{cite journal |last=Kramnick |first=Isaac |title=Eighteenth-Century Science and Radical Social Theory: The Case of Joseph Priestley's Scientific Liberalism |journal=Journal of British Studies |pages=1–30 |publisher=Cambridge University Press on behalf of The North American Conference on British Studies |volume=25 |issue=1 |date=January 1986 |jstor=175609 |doi=10.1086/385852 |s2cid=197667044 |ref=kramnick1981}}
* {{cite book |last=Schofield |first=Robert E. |title=The enlightenment of Joseph Priestley : a study of his life and work from 1733 to 1773 |volume= |author-link= |publisher=University Park, Pa. : Pennsylvania State University Press |year=1997 |isbn=978-0-2710-1662-7 |url=https://archive.org/details/enlightenmentofj0000scho |ref=schofield1997}}
* {{cite book |last=Schofield |first=Robert E. |title=The Enlightened Joseph Priestley: A Study of His Life and Work from 1773 to 1804 |volume= |author-link= |publisher= Penn State Press|year=2004 |isbn=978-0-2710-3246-7 |url=https://books.google.com/books?id=PEeaCgAAQBAJ |ref=schofield2004}}
* Smith, Edgar F. ''[https://archive.org/details/priestleyinamer00smitgoog Priestley in America, 1794–1804]''. Philadelphia: P. Blakiston's Son and Co., 1920.
* Tapper, Alan. "Joseph Priestley". ''Dictionary of Literary Biography'' 252: ''British Philosophers 1500–1799''. Eds. Philip B. Dematteis and Peter S. Fosl. Detroit: Gale Group, 2002.
* Thorpe, T. E. ''[https://archive.org/details/josephpriestley01thorgoog Joseph Priestley]''. London: J. M. Dent, 1906.
* Uglow, Jenny. ''The Lunar Men: Five Friends Whose Curiosity Changed the World''. New York: Farrar, Straus and Giroux, 2002. {{ISBN|0-374-19440-8}}.
* {{cite book |last=Van Doren |first=Carl |title=Benjamin Franklin |author-link=Carl van Doren |publisher=New York, Garden City Publishing Company |year=1938 |url=https://archive.org/details/benjaminfranklin0000carl_l1w6/page/n5/mode/2up |ref=vandoren1938}}
{{refend}}

'''Secondary materials'''
{{refbegin}}
* Anderson, R. G. W. and Christopher Lawrence. ''Science, Medicine and Dissent: Joseph Priestley (1733–1804)''. London: Wellcome Trust, 1987. {{ISBN|0-901805-28-9}}.
* Bowers, J. D. ''Joseph Priestley and English Unitarianism in America''. University Park: Pennsylvania State University Press, 2007. {{ISBN|0-271-02951-X}}.
* Braithwaite, Helen. ''Romanticism, Publishing and Dissent: Joseph Johnson and the Cause of Liberty''. New York: Palgrave Macmillan, 2003. {{ISBN|0-333-98394-7}}.
* Conant, J. B., ed. "The Overthrow of the Phlogiston Theory: The Chemical Revolution of 1775–1789". ''Harvard Case Histories in Experimental Science''. Cambridge: Harvard University Press, 1950.
* Crook, R. E. ''A Bibliography of Joseph Priestley''. London: Library Association, 1966.
* Crossland, Maurice. "The Image of Science as a Threat: Burke versus Priestley and the 'Philosophic Revolution'". ''British Journal for the History of Science'' 20 (1987): 277–307.
* Donovan, Arthur. ''Antoine Lavoisier: Science, Administration and Revolution''. Cambridge: Cambridge University Press, 1996. {{ISBN|0-521-56218-X}}
* Eshet, Dan. "Rereading Priestley". ''History of Science'' 39.2 (2001): 127–59.
* Fitzpatrick, Martin. "Joseph Priestley and the Cause of Universal Toleration". ''The Price-Priestley Newsletter'' 1 (1977): 3–30.
* Garrett, Clarke. "Joseph Priestley, the Millennium, and the French Revolution". ''Journal of the History of Ideas'' 34.1 (1973): 51–66.
* Fruton, Joseph S. ''Methods and Styles in the Development of Chemistry''. Philadelphia: American Philosophical Society, 2002. {{ISBN|0-87169-245-7}}.
* {{cite book |last1=Gray |first1=Henry Colin |last2=Harrison |first2=Brian Howard |title=Joseph Priestly |volume=XLV |author-link= |publisher=Oxford; New York : Oxford University Press: Oxford dictionary of national biography |year=2004 |isbn= |url=https://archive.org/details/oxforddictionary45matt/page/n5/mode/2up |pages=351–359– |ref=oxford2004}}
* Kramnick, Isaac. "Eighteenth-Century Science and Radical Social Theory: The Case of Joseph Priestley's Scientific Liberalism". ''Journal of British Studies'' 25 (1986): 1–30.
* [[Thomas Kuhn|Kuhn, Thomas]]. ''[[The Structure of Scientific Revolutions]]''. 3rd ed. Chicago: University of Chicago Press, 1996. {{ISBN|0-226-45808-3}}.
* Haakonssen, Knud, ed. ''Enlightenment and Religion: Rational Dissent in Eighteenth-Century Britain''. Cambridge: Cambridge University Press, 1996. {{ISBN|0-521-56060-8}}.
* McCann, H. ''Chemistry Transformed: The Paradigmatic Shift from Phlogiston to Oxygen''. Norwood: Alex Publishing, 1978. {{ISBN|0-89391-004-X}}.
* McEvoy, John G. "Joseph Priestley, 'Aerial Philosopher': Metaphysics and Methodology in Priestley's Chemical Thought, from 1762 to 1781". ''Ambix'' 25 (1978): 1–55, 93–116, 153–75; 26 (1979): 16–30.
* McEvoy, John G. "Enlightenment and Dissent in Science: Joseph Priestley and the Limits of Theoretical Reasoning". ''Enlightenment and Dissent'' 2 (1983): 47–68.
* McEvoy, John G. "Priestley Responds to Lavoisier's Nomenclature: Language, Liberty, and Chemistry in the English Enlightenment". ''Lavoisier in European Context: Negotiating a New Language for Chemistry''. Eds. Bernadette Bensaude-Vincent and Ferdinando Abbri. Canton, MA: Science History Publications, 1995. {{ISBN|0-88135-189-X}}.
* McEvoy, John G. and J.E. McGuire. "God and Nature: Priestley's Way of Rational Dissent". ''Historical Studies in the Physical Sciences'' 6 (1975): 325–404.
* McLachlan, John. ''Joseph Priestley Man of Science 1733–1804: An Iconography of a Great Yorkshireman''. Braunton and Devon: Merlin Books, 1983. {{ISBN|0-86303-052-1}}.
* McLachlan, John. "Joseph Priestley and the Study of History". ''Transactions of the Unitarian Historical Society'' 19 (1987–90): 252–63.
* Philip, Mark. "Rational Religion and Political Radicalism". ''Enlightenment and Dissent'' 4 (1985): 35–46.
* Rose, R. B. "The Priestley Riots of 1791". ''Past and Present'' 18 (1960): 68–88.
* Rosenberg, Daniel. ''Joseph Priestley and the Graphic Invention of Modern Time''. Studies in Eighteenth Century Culture 36(1) (2007): pp.&nbsp;55–103.
* [[Donald Rutherford (philosopher)|Rutherford, Donald]]. ''[[Leibniz and the Rational Order of Nature]]''. Cambridge: Cambridge University Press, 1995. {{ISBN|0-521-46155-3}}.
* Schaffer, Simon. "Priestley Questions: An Historiographic Survey". ''History of Science'' 22.2 (1984): 151–83.
* Sheps, Arthur. "Joseph Priestley's Time ''Charts'': The Use and Teaching of History by Rational Dissent in late Eighteenth-Century England". ''Lumen'' 18 (1999): 135–54.
* Watts, R. "Joseph Priestley and Education". ''Enlightenment and Dissent'' 2 (1983): 83–100.
{{refend}}

'''Primary materials'''
{{refbegin}}
* Lindsay, Jack, ed. ''Autobiography of Joseph Priestley''. Teaneck: Fairleigh Dickinson University Press, 1970. {{ISBN|0-8386-7831-9}}.
* Miller, Peter N., ed. ''Priestley: Political Writings''. Cambridge: Cambridge University Press, 1993. {{ISBN|0-521-42561-1}}.
* Passmore, John A., ed. ''Priestley's Writings on Philosophy, Science and Politics''. New York: Collier Books, 1964. <!-- No ISBN. -->
* [[John Towill Rutt|Rutt, John T.]], ed. ''Collected Theological and Miscellaneous Works of Joseph Priestley''. Two vols. London: George Smallfield, 1832. <!-- No ISBN, of course. -->
* Rutt, John T., ed. ''Life and Correspondence of Joseph Priestley''. Two vols. London: George Smallfield, 1831. <!-- No ISBN, of course. -->
* Schofield, Robert E., ed. ''A Scientific Autobiography of Joseph Priestley (1733–1804): Selected Scientific Correspondence''. Cambridge: MIT Press, 1966. <!-- No ISBN. -->
{{refend}}

==External links==
{{Wikiquote}}
{{commons category|Joseph Priestley}}
{{wikisource author}}
* [[List of works by Joseph Priestley#Links to online works in full-text|Links to Priestley's works online]]
* {{cite IEP |url-id=priestly |title=Joseph Priestley}}
* [http://www.priestleysociety.net/ The Joseph Priestley Society]
* [http://www.josephpriestley.com/index.html Joseph Priestley Online] {{Webarchive|url=https://web.archive.org/web/20110713120604/http://www.josephpriestley.com/index.html |date=13 July 2011 }}: Comprehensive site with bibliography, links to related sites, images, information on manuscript collections, and other helpful information.
* [http://www.bbc.co.uk/radio4/history/inourtime/inourtime_20071115.shtml Radio 4 program on the discovery of oxygen] by the [[BBC]]
* [http://dewey.library.upenn.edu/sceti/smith/PortraitList.cfm?ScientistID=223&visited=smithScientist Collection of Priestley images] {{Webarchive|url=https://web.archive.org/web/20090423053556/http://dewey.library.upenn.edu/sceti/smith/PortraitList.cfm?ScientistID=223&visited=smithScientist |date=23 April 2009 }} at the Schoenberg Center for Electronic Text and Image
* {{Gutenberg author | id=34121}}
* {{Internet Archive author |sname=Joseph Priestley}}
* {{Librivox author |id=2824}}

===Short online biographies===
* "[https://web.archive.org/web/20111002141806/https://portal.acs.org/portal/acs/corg/memberapp?_nfpb=true&_pageLabel=PP_ARTICLEMAIN&node_id=925&content_id=CTP_004441&use_sec=true&sec_url_var=region1 Joseph Priestley: Discoverer of Oxygen]" at the [[American Chemical Society]]
* [https://web.archive.org/web/20070228055714/http://www.woodrow.org/teachers/chemistry/institutes/1992/Priestley.html Joseph Priestley] at the [[Woodrow Wilson National Fellowship Foundation]]
* [http://www.spaceship-earth.org/Biograph/Priestley.htm Joseph Priestley] from the ''[[Encyclopædia Britannica]]''
* {{cite EB1911|wstitle=Priestley, Joseph}}
* {{cite DNB |wstitle=Priestley, Joseph}}
* [http://explorepahistory.com/hmarker.php?markerId=858 ExplorePAHistory.com]
* {{cite web |last=Poliakoff |first=Martyn |title=Joseph Priestley |url=http://www.periodicvideos.com/videos/feature_priestley_glasses.htm |work=[[The Periodic Table of Videos]] |publisher=[[University of Nottingham]] |author-link=Martyn Poliakoff}}

{{Joseph Priestley}}
{{Copley Medallists 1751-1800}}
{{Visualization}}
{{Authority control}}

{{DEFAULTSORT:Priestley, Joseph}}
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