Joseph Priestley
1733 - 1804

Priestley's Youth. Joseph Priestley was born near Leeds, Great Britain on March 13, 1733.  His father was a cloth-dresser.  His mother died in childbirth when Joseph was seven years old.  As a result, he was raised by his aunt.  Joseph was ill as a child and his early education was neglected.  However, by his mid-teen years, he had discovered his natural aptitude for languages and learned Hebrew, Latin and Greek.  His aunt, a devout Calvinist, encouraged Priestley to become a minister and at age 19 he entered the Dissenting Academy at Daventry, a non-conformist school for ministers. 

Religious non-conformist.    Educated to be a minister, his first position was that of assistant to the Presbyterian minister at Needham Market.  His theological philosophy grew extraordinarily liberal and he gradually came to question the divinity of Jesus. His congregation disapproved and Priestley left for a series of other positions and a 3-year position as the minister at Nantwich.  As one who openly professed his views, he was in continual dispute with more traditional religious thinkers of the time.  Eventually he found his niche as tutor of languages at Warrington Academy where he stayed for six years and was recognized for having "added greatly to the celebrity of the institution."1  In 1762, Priestley was ordained a minister and in the same year married Mary.

Political non-conformist. Priestley supported both the French and American Revolutions and believed that they represented the beginning of the destruction of all early regimes as foretold in the Bible as a harbinger of the Kingdom of God.

Personality.   Despite Priestley's incendiary views, Priestley was described as a courteous gentleman of attractive and winning personality.

Brewery Gas.   In 1767, Priestley and Mary moved to Leeds where he took charge of Mill Hill Chapel.  They lived next to a brewery and Priestley soon began experiments on 'fixed air' produced in unlimited supply by the brewery.  In 1772 he announced his invention of soda-water.

1773 - 1780. The Priestleys, now including two sons, moved to Bowood, the residence of Sir William Petty, another liberal political philosopher.  At Bowood, Priestley was nominally the librarian, but had much time for experimentation and writing.  His religious and philosophical opinions caused so much offense, he was forced to move again, this time to Birmingham.
Pneumatic chemist.   Priestley was self-taught in chemistry but possessed both curiosity and manipulative skills that served him well in the laboratory.  Priestley was the first pneumatic chemist and is credited with the discovery of eight gases, a record that still stands.


• nitrous vapor (NO2)
• nitrous air diminished (N2O)
• acid air (HCl)
• inflammable air3 (CO)
1773:4 • alkaline air (NH3)
1774:4 • dephlogisticated air (O2)
• vitriolic air (SO2)
1775:4 • fluor acid air (SiF4)

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'Dephlogisticated air' (Oxygen) On August 1, 1774 first prepared oxygen by directing the sun's light with a large (12-inch diameter) burning lens onto a sample of red mercurius calcinatus per se (now HgO).

mercurius calcinatus per se + heat yields quicksilver + dephlogisticated air

[now: HgO(s)  Hg(l) + O2(g)]

"[My] breast felt particularly light and easy for some time afterwards...... Who can tell, but that, in time, this pure air may become a fashionable article of luxury.  Hitherto only two mice and myself have had the privilege of breathing it."5

Lunar Society.  In Birmingham, Priestley joined the Lunar Society, a small body of men interested in scientific pursuits.  The Society met on the Monday nearest the full moon of each month in order to have the benefit of its light on the way home.

Ransacked!   Priestley's views on religion and politics eventually caught up with him.  On July 14, 1791, the anniversary of the destruction of the Bastille, a Birmingham mob (incited by authority) ransacked and burned Priestley's house and laboratory.  Fortunately Priestley and family had escaped the mob which vowed to kill him.  After a 3-year period in London, Priestley and his wife followed their sons to America.  They settled in Pennsylvania.

Phlogiston forever! Priestley was the last of the great gas chemists to ardently support the phlogiston theory.  In 1800, near the end of his life, he wrote the book Doctrine of Phlogiston Established.  He argued with Lavoisier over interpretations of experimental results.  Because he was a far better experimentalist than a logical reasoner, and because he adamantly supported a theory that was inherently flawed, his explanations were often inconsistent.  Ironically, it was Priestley's own experiments that undermined the phlogiston theory and guided Lavoisier to propose the oxygen theory, forming the basis of modern chemistry.  Priestley died on February 6, 1804.  Towards the end of his life, he reflected:

"I have a tolerably good habit of circumspection with regard to facts; but as to conclusions from them, I am not apt to be very confident."5

Lasting accomplishments.

•  Invented soda water, 1772, used as the basis for the soft drink industry

•  Pneumatic chemist.  Like Cavendish, Priestley was a pioneer in the manipulation of gases, including collection in bottles by water displacement and methods for transferring gases.  His pneumatic trough featured a shelf.2, 6

•  World Record holder.  Discoverer of eight gases.

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Biographical Summary of Joseph Priestley’s Life

13 March 1733 Born at Birstall, near Leeds (see pictures)
1742 (age 9) Adopted by his aunt, Sarah Keighley 
1745 (age 12) Attended Batley Grammar School 
1752 (age 19) Entered the Academy at Daventry (Map and pictures)
1755 (age 22) First appointment: Assistant Minister (and later as minister) at Needham Market, Suffolk 
1758 (age 25) Minister at Nantwich, Cheshire (and established a small school) 
1761 (age 28) Appointed Tutor of Languages and Literature at Warrington Academy for sons of dissenters.  (Map and pictures)
18 May 1762 (age 29) Ordained at Warrington
23 June 1762 (age 29) Married Mary Wilkinson 
1766 (age 33) Published “The History and Present State of Electricity” 
1766 (age 33) Elected Fellow of the Royal Society
1767 (age 34) Minister at Mill Hill Chapel, Leeds  (Map and pictures)
1772 (age 39) Moved to Calne, where he was employed as librarian and literary companion of the Earl of Shelburne.  Priestley lived in Calne and the Earl of Shelburne lived at Bowood House, a few miles west of Calne.  Priestley kept a laboratory at Bowood.  (Map and pictures)
1 August 1774 (age 41) Discovered oxygen
1780 (age 47) Moved to Birmingham; elected minister of New Meeting, Birmingham  (Pictures)
1780s Member of the Lunar Society, Birmingham
14 July 1791 (age 58) House, chapel and possessions destroyed in Birmingham Riots (because of Priestley’s support of French Revolutionaries) (Pictures)
7 April 1794 (age 61) Emigrated to Northumberland, Pennsylvania with wife and family
6 February 1804 (age 70) Died after suffering from pleurisy and a fall


Apparatus in Joseph Priestley’s laboratory at Bowood, engraving 1777 from Priestley’s book “Experiments and Observations on Different Kinds of Air”


1 Famous Chemists, Sir William Tildon, London, 1921.

2 "Observations on Different Kinds of Airs," Phil. Trans., London 1772.  Also in this paper, Priestley describes nitrous air (nitric oxide, NO), (previously obtained by Boyle) and phlogisticated air (nitrogen, N2).  (previously discovered by Cavendish)

3  Priestley did not differentiate it from the other form of inflammable air, hydrogen.

4 "Experiments and Observations on Different Kinds of Airs," London 1774, 1775 and 1777 (3 volumes)

5 A Short History of Chemistry, J. R. Partington, 3rd edition, (1957)

6 Cavendish's pneumatic trough had no shelf

(This page last updated 25 September 2001)