William Priestley (7 May 1771 – 1838) was the third child and second son of Joseph Priestley and his wife Mary Wilkinson. He spent some time in France, before migrating to the US in 1793, taking the oath of citizenship on 8 October 1798. In 1801 he moved to Louisiana, with the intention of establishing a school in Point Coupee Parish. Some time between 1804 and 1807, William purchased a sugar plantation on the west bank of the Mississippi River.

William Priestley's early life and character William Priestley was born in Basinghall Street, Leeds, in the manse associated with Mill Hill Chapel, where his father was minister. He was educated in Bristol in John Prior Estlin's school, before spending two years at Daventry Academy, his father's alma mater, 1787–89. William Priestley was a mild-tempered and softly-spoken bohemian with long brown hair thrown back over his shoulders, and a passion for nature and music. He was a proficient flautist, who spoke French and German, studied Anglo-Saxon texts, and read Norse mythology. He carved wooden chess-pieces, and sculpted clay models of ancient temples.Life of Mary Anne Schimmelpenninck (2 vols, London, 1858), I, 132-5, 156-8. Tony Rail, "William Priestley Vindicated, with a Previously Unpublished Letter", 'Enlightenment and Dissent', no.28 (2012), 150-195. He was not inclined towards a career in commerce. His father, writing to a friend, regretted that William's "temper [frame of mind] and high spirit [zest for life], will hardly suit trade."In the eighteenth-century, temper indicated either a calmness of mind, or simply frame of mind; high spirit meant ebullience or zest for life. In this, William and his father were very much alike, for, when he was nineteen, Joseph Priestley himself, had rejected a firm offer of a career in commerce; as a minister at Needham Market, his congregation had objected to Priestley's "gay and airy disposition;" and at Nantwich he had a habit of vaulting over the counter of the grocer's shop at which he lodged.Anne Holt, A life of Joseph Priestley (Oxford, 1931), 7, 19. Regrettably some modern historians have misunderstood contemporary word-usage, and have read the clause: "William's temper and high spirit, will hardly suit trade," in a twenty-first-century idiom, mistakenly accusing William of being "too high-spirited and hot-tempered;"Robert E Schofield, The enlightened Joseph Priestley (Pennsylvania, 2004), 317. and erroneously denouncing him as the "black sheep" of the family.James J Hoecker, Priestley pedigree, Price-Priestley Newsletter, no.4 (1980), 75-8.

In the Summer of 1789 William accompanied his uncle William Wilkinson on a business trip through northern Europe and France, and was in Paris during the storming of the Bastille. When William Wilkinson return to England, William Priestley went on to Germany, as tutor to a family in Frankfurt.Rail, 151-4. Despite William's disinclination towards office work, his father was prepared to pay for him to be articled to a merchant, though he baulked at the £1,000 Benjamin Vaughan had wanted.Priestley to Lindsey, 27 Oct 1790 (Mills). In December 1790, William Russell agreed to take William on as an articled accounts clerk for three years, with a view to him looking after the Russell brothers' interests in America or France. William Priestley was working for the Russells at the time of the Birmingham riots. He insisted on remaining at home, "Fairhill", as his parents fled, initially to ensure that the kitchen fire and candles were fully extinguished. William helped round up numerous young volunteers, with whom he laboured several hours to remove as many of Joseph Priestley's books and manuscripts as they could, continuing to carry books and furniture down the staircase even as the handrails, banisters and treads were being systematically demolished by the leading rioters. After the riots, William remained in Birmingham, gathering up such of his father's books and manuscripts as had survived.TNA, HO 42/19/418-421, 438. Rail, 154. In the Autumn of 1791, William joined his father in London, where Joseph Priestley was settling into a new home in Lower Clapton, while William's mother was with his sister at Heath-forge, Wombourne; brother Joseph was working in Manchester; and brother Henry was at school in Bristol. Being Joseph Priestley's only relative in London (apart from his uncle Timothy, minister at Jewin Street chapel), William helped manage the workmen carrying out numerous repairs and works, and helped his father arrange his library and set up his laboratory. William assisted in managing the household, such as it was, and looked after the dietetic needs of his father, who suffered a bowel condition throughout his adult life, with episodes of severe diarrhoea.Rail, 155-6. The noted Unitarian benefactress, Mrs Elizabeth Rayner, was impressed enough by William's practical care and filial concern for his father, to single him out for particular mention in her will.PCC copy of will dated 19 Oct 1795, TNA PROB 11/1345.

France (1792)

After his brother Joseph's marriage to Elizabeth Rayner in April 1792, William Priestley travelled to Paris, at the behest of William Russell, who was rebuilding his mercantile business from Gloucester. At Paris on 8 June 1792, President Tardiveau introduced William to the Assemblée législative. William asked M Français to read out his brief address, because of his "voix extrêment faible":

William Priestley is eager to pay his just respects to the first magistrates of a people who are celebrated not only in England, but amongst all nations that value liberty, energy [l'énergie had been a rallying cry of the revolution], and virtue. "Go", said his father, "live amongst this brave and welcoming people; learn from them to detest tyranny, and to love liberty." William Priestley therefore comes to this land of France. He proposes to make his home here, and seeks to enjoy the rights of a citizen of France (a title which he prefers a hundred times to that of a king of an arbitrary state) – a member of a sovereign people that will greatly honour him by his adoption. In the exercise of his duties as citizen and soldier, he will always keep in mind, and in his heart, the public spirit of the nation, the energy of its magistrates, and the lessons of his father.Jérôme Mavidal & Emile Laurent, Archives parlementaires de 1787 à 1860, ser.1, XLIV (Paris, 1894), 692-4. Translation in Rail, 157.

After a long speech by Tardiveau extolling the virtues of Joseph Priestley, interrupted fourteen times by applause, the Assemblée conferred letters of naturalization, and declared William an adopted son of France. The caricaturist James Sayers produced an etching of the event.

New England and Pennsylvania (1792-1801) Following the September Massacres, William migrated to America directly from France. He visited Boston, and spent some time in Brattleboro, Vermont, with the also newly arrived family of William Wells, who was looking to buy a farm there. In the Autumn of 1794, after visiting his parents in New York, William stayed for a while in Boston, spending time with the Unitarian minister Dr James Freeman, and visiting Freeman's Harvard classmate Dr William Bentley, Unitarian pastor of East Church, Salem; though, for several weeks at a time, in October and December, William was ill with a high fever, perhaps malaria.The diary of William Bentley (4 vol., Salem, 1905-14), vol.2, 112-4, 127; Priestley to John Wilkinson, 17 Dec 1795 (Warrington Library, WMS2/mf8). After recovering his health, William removed to the backwoods of Northumberland County, Pennsylvania, at Point township (now Northumberland borough) in February 1795. Here, William and his brother Henry bought a 284-acre plot of woodland, which they attempted to transform into a farm, later called "Fairhill", felling and uprooting trees, and obtaining lime to sweeten the soil by building their own lime kilns.Rail, 150-195. Henry Priestley died 11 December 1795, possibly of malaria which he may have contracted after landing at New York.

On 3 February 1796, William Priestley married Margaret Foulke, "an amiable and sensible young woman" of Middle Paxton, at Paxtang Presbyterian Church, Harrisburg.Rail, 160-61; Philadelphia Minerva, 13 Feb 1796 A few days later, Joseph Priestley travelled alone to Philadelphia, William's mother being too unwell to travel. Mary Priestley's continuing ill-health would force the doctor to cancel planned excursions to New York and Boston, and return home early, at the end of May.Dr Priestley [at Philadelphia] to John Fellows [1759-1844, bookseller at New York], 11 April 1796, Bibliothèque municipale de Nantes, Ms 674-170. Joseph Priestley Jr.'s wife, Elizabeth Ryland-Priestley, a middle-class Englishwoman could offer little in the way of care; so, throughout 1796, Margaret Foulke-Priestley, a frontierswoman not slow to roll up her sleeves, nursed Mary Priestley, moving in, and eventually bringing her own sister, so that between the two of them they could nurse Mary Priestley twenty-four hours a day.Priestley to Lindsey, 19 September 1796, cit. Jenny Graham, "This unhappy country of ours; Extracts of letters, 1793-1801, of Theophilus Lindsey", Enlightenment and Dissent, no.18 (1999), 147n. Margaret took over many the household duties, which, on Joseph Priestley's return included dealing with his dietary needs. She introduced the Priestleys to the benefits of Indian meal or Maize flour, suggesting advantages for Dr Priestley's health.Rail, 160-162 Despite Margaret's nursing care, Mary Priestley died Saturday 17 September 1796.