As scientist, Unitarian controversialist, and proponent of republican values, Joseph Priestley exerted enormous influence in English and American intellectual circles, though his life ended in decline and isolation. Born into middling circumstances in Yorkshire, Priestley was raised by well to do relatives who had fallen under the sway of dissenting doctrine. A promising student, he prepared for the ministry, but as a result of ill health and his unpalatable religious affiliations he was prevented from entering either Oxford or Cambridge, choosing instead to attend the dissenting academy at Daventry.

Receiving his degree in 1755, Priestley discovered that his road into the ministry was hampered by his unorthodox views and unfortunate voice, and while filling a minor pulpit, he found that his first real taste of success came instead in teaching. By 1761, his reputation as an educator had grown to such an extent that he was offered the position of Professor of Languages at the prestigious Warrington Academy, and the next year his life improved further when he was ordained and married Mary Wilkinson, daughter of a Welsh ironmaster. In education as in religion, Priestley's approach was insistently unorthodox. He introduced the study of modern history, law, economics, and social sciences into the standard curriculum, and although he left Warrington in 1767 to return to the more stable income of the ministry, accepting an appointment in Leeds, his reputation as a scholar and scientist had grown enormously. At Leeds, he became acquainted with Benjamin Franklin who encouraged his electrical experimentation, and Priestley's work on light and vision found a wide readership.

By 1773, Priestley had attracted the attention of William Petty, 1st Earl of Shelburne (1737-1805), and was offered a position in the Earl's household as tutor, librarian, and companion. The grandson of the great scientist of the same name, Shelburne was a prominent politician, a future Prime Minister, and a magnanimous patron. Through him, Priestley not only achieved financial security, but gained entrée into the highest of Britain's intellectual, social, and scientific circles. At Bowood, Shelburne's estate, Priestley pursued the implications of a paper he had presented to the Royal Society in 1772, "On Different Kinds of Air," and thus laid the foundation of his international reputation as a chemist. In his book, Experiments and Observations on Different Kinds of Air (1774), he built upon the work of Joseph Black and James Cavendish to identify nine distinct gases, three of which were previously unknown. Most famously, on August 1, 1774, he produced "dephlogisticated air" - oxygen -- by heating red mercuric oxide, demonstrating beyond cavil that air was not an element. In isolating oxygen, Priestley noted its importance in combustion, but clung to a belief in phlogistic theory until the end of his life, becoming, at the end, the last important chemist of that stripe. Ironically, it was his isolation of oxygen, particularly as pursued by Antoine Lavoisier, that became the nail in the phlogistic coffin. His scientific work earned Priestley admission into the French Academy of Sciences in 1772, the St. Petersburg Academy in 1780, and through Franklin, to the American Philosophical Society in 1784.

During the later 1770s, divisions between Priestley and Shelburne deteriorated over Priestley's support for the American cause during the Revolution and over his unorthodox religious views. While the two remained cordial, Priestley left the Shelburne home in 1780 and settled at Birmingham, near his brother-in-law, John Wilkinson. Whereas his scientific work had flourished at Bowood, his religious writings flourished in Birmingham, and he became a leading dissenting voice, assailing the corruptions of the Anglican hierarchy and Trinitarianism, and beginning the enduring association with Unitarianism that he considered his true life's work. At Birmingham he was also drawn into the Lunar Society, an engaging, salon-like group of enlightened minds that included Erasmus Darwin, James Watt, and Matthew Boulton.

The halcyon days in Birmingham, however, were not to last. Priestley's religious and political views conspired to ensure his supreme unpopularity during the shifting political tides of the French Revolutionary era, and he became a lightning rod for the government-inspired backlash against republicanism and "radicalism" of all sorts. The wrath of the mob was turned against him directly during the Birmingham riots of July, 1791, when his house, library, and laboratory were set aflame. Taking refuge with William Vaughan, brother of John and Benjamin, Priestley whisked his children out of the country and in April, 1794, finally abandoned England himself for the United States.

Priestley and his wife, Mary, settled in the relatively remote town of Northumberland, Pennsylvania, 150 miles west of Philadelphia, initially imaging that he could enjoy the country life and yet travel into the metropolis for intellectual stimulation. Little, however, went as Priestley had planned. His plans of establishing a community at Northumberland devoted to religious and political freedom were unavailing, travel into Philadelphia proved far too difficult, and in his rural remove he was only barely able to continue his scientific research. If it cannot be traced to Birmingham, Priestley's protracted decline began in 1795 and 1796 when he lost his son and wife successively, and thereafter he was never in complete health himself. Furthermore, Priestley was no more immune in the United States than he had been in England to ill political winds. When his friend, Thomas Cooper, was arrested for violating the Alien and Sedition Acts, Priestley was suspected of aiding and abetting, and although his deportation was prevented by the intervention of his friend John Adams, he became a preferred target for the literary quills of Peter Porcupine, William Cobbett. Although Priestley continued to serve in the Unitarian pulpit and wrote on religious matters for several years more, his last scientific work (on the long-abandonded phlogiston) was published in 1796. He died after a brief illness on February 6, 1804, and is buried in the Quaker cemetery in Northumberland.

The Joseph Priestley Papers consists of 46 letters and 70 copies of letters written by the scientist, educator, and Unitarian minister, Joseph Priestley, mostly to the Librarian of the American Philosophical Society, John Vaughan, and Priestley's brother-in-law, John Wilkinson. The focus in these letters is at once personal and intellectual, providing insight into Priestley's financial life, the vicissitudes of his work and political and religious ideas.

The several letters written by Priestley to Vaughan in the years between the Birmingham riots and his emigration to America provide valuable insight into a variety of personal and financial matters (Vaughan held power of attorney for him), cloaked, of course, in the violence of the anti-Republican backlash. Priestley's difficult decision to send first his sons, then himself abroad due to the "increasing bigotry and violence of the High church party" in England are thoroughly chronicled, as are his bitterness against the confluence of "church power," xenophobia, and anti-Republicanism.

Although Priestley's post-emigration letters from Northumberland tend to be more perfunctory, relating primarily to business matters, they provide a useful perspective on his intellectual isolation and on the toll that decades of political controversy had taken upon the man. His dismay at anti-tax hysteria in western Pennsylvania during the Whiskey Rebellion is evident in his lament that "People will chuse to do without government rather than pay so dear for it, and if they really chuse this, they should be left to themselves." Other letters reveal Priestley's frustration at his inability to obtain decent scientific instruments in America - and implicitly, the inability to advance his own research agenda -- and his publications continue to make their mark, particularly in his uneven relationship with the Porcupine, William Cobbett.

The balance of the collection consists of an additional five letters of Priestley, including a fine letter to Dr. [William] Withering (1741-1799), October 27, 1795, discussing Priestley's nostalgia for the comradery of the Lunar Society, his on-going chemical experiments with phlogisticated air, and much more. There are also photostats of 68 letters to and from Priestley's brother-in-law, John Wilkinson (1789-1802), drawn from originals held in the Municipal Library, Warrington, England. These provide particularly valuable insight into Priestley's personal response to the Birmingham riots, and his reactions to the isolated life in Northumberland, and they contain important commentary on Priestley's religious, political, and scientific views from the 1790s until 1802.

None. Permission to make copies from the Priestley-Wilkinson correspondence granted September, 1981.

Photostats from the Municipal Library, Warrington, England, courtesy of the Library through Whitfield J. Bell, 1951.

Cite as: Joseph Priestley Papers, American Philosophical Society.

Priestley appears as a correspondent or is mentioned in several other collections at the American Philosophical Society, including in the Benjamin Franklin Papers (eight letters from Johannes Ingenhousz to Franklin, 1774-1782); the John Pershouse Papers (four from John Pershouse to James Pershouse, 1802-1805), and the Richard Price Papers (four from Richard Price to Charles Chauncy and Benjamin Franklin, 1766-1779).

A manuscript copy of Priestley's "Experiments relating to phlogiston and the conversion of water into air," 1783 (32 pp.), is housed separately at 540.1 P931.