Joseph Priestley: Docter Phlogiston or ReverendOxygen?

Patricia Fara

Clare College, Cambridge, CB2 1TL, UK

Feature Endeavour Vol.34 No.3

In propaganda material, people are often presented inblack-and-white terms as either a villain or a hero.Although Joseph Priestley is denigrated for believingin the discredited substance phlogiston, he is also cele-brated for discovering oxygen.

Although he was a keen supporter of the French Revolu-tion, the chemist Joseph Priestley (1733–1804) celebratedits second anniversary with nothing more seditious than agame of backgammon and a quiet dinner at home. A coupleof hours later, he watched in horror from a nearby hill ashis house and possessions were destroyed, including hisvaluable collections of books and instruments. A religiousradical, Priestley had been deliberately victimized bygangs of rioters who were roving around Birmingham thatnight, attacking Dissenters’ property and protected by therefusal of local magistrates to leave their discussion in thelocal pub and intervene.1

Only a fortnight earlier, on 1 July 1791, Priestley hadbeen singled out for less physical abuse by an unidentifiedcaricaturist (Figure 1). In reality, Priestley was a mild-mannered man, often compared to a woodpecker becauseof his beaky nose and the staccato rhythm of his stammer-ing speech. In contrast, here the exaggerated nose andbeetling brow of his coarse features signal that Priestley isa shady, sinister character. To emphasise his dastardlyintentions, his pockets are stuffed with imaginary pamph-lets carrying provocative titles such as Gunpowder andRevolution Toasts. Beneath his feet, the BIBLE explainedAway refers to Priestley’s unorthodox religious position,while the firebrand tracts in his hands are his own Essayon Government and a Political Sermon that had beenprinted by request of the Birmingham Dissenters’ Com-mittee two years earlier.2

The dark fumes of smoke and the mocking nickname‘Docter Phlogiston’ refer to Priestley’s fame as one ofEngland’s greatest chemical experimenters. For much ofthe eighteenth century, the standard account of burningrelied on a weightless, invisible substance called phlogis-ton. Originally proposed to explain refining processes inGermanmines, this theoretical entity remained importantfor many decades in France and England because it pro-vided a useful scientific model. Metals were said to changecolour when heated because the dirty phlogiston they

Corresponding author: Fara, P. (pf10006@cam.ac.uk)1 Jay, M. (2009) The Atmosphere of Heaven: The Unnatural Experiments of

Dr Beddoes and his Sons of Genius (New Haven, Yale), pp. 1–10.2 Fitzwilliam, M. (1984) Priestley in caricature. In Oxygen and the Conversion of

Future Feedstocks: The Proceedings of the Third BOC Priestley Conference, pp. 346–69,London: Royal Society of Chemistry, 1984.

Available online 14 August 2010

www.sciencedirect.com 0160-9327/$ – see front matter � 2010 Elsevier Ltd. All rights reserve

contained was being driven off; conversely, smelting oresat high temperatures caused them to absorb phlogistonand be converted into metals.

Chemical research was vital for Britain’s burgeoningindustrial operations, and Priestley was a leading prac-titioner, an enthusiastic participant in the networks ofMidlands experimenters and factory owners. Takingadvantage of nearby breweries, he had developed a refresh-ing new drink called soda water, which he hoped wouldprovide a cure for scurvy on long sea voyages. Not beingfinancially astute, Priestley handed over the recipe to a MrSchweppes, and so lost the opportunity for two centuries ofbrand identification. He did, however, carry out a moremomentous experiment: Priestley isolated the elementnow known as oxygen, the name subsequently inventedby his French rival, Antoine Lavoisier. When Priestleyfound that his new gas seemed to be exceptionally pureand life-supporting, he decided it was dephlogisticated air,a label belonging to a theoretical framework that he neverrelinquished.

The close contemporary ties between politics and reli-gion made this a savage image. In his caption, the anon-ymous caricaturist has punned on Priestley’s name bycalling him a political priest, and three years later, theprint reappeared with a new title, The Reverend Philoso-pher. The clumsiness of the lettering reflects the engravingprocess, which involved carving out amirror-image, so thatthe missing ‘i’ in politician is presumably a slip made whilewriting backwards. The ‘e’ in ‘Docter’ might perhaps be dueto the writer’s own poor spelling, but the correct renditionof the more difficult ‘phlogiston’ suggests that the mistakeis a deliberate allusion to Priestley’s lack of universityeducation – as a Dissenter, he was banned from bothOxford and Cambridge.

In this post-Revolutionary era, chemistry was fraughtwith political significance. The greatest innovations werebeing introduced in France, and Lavoisier’s interest ingunpowder was a gift to English satirists, who madecountless puns about explosive theories, airy speculations,fumes of discontent, inflammatory ideas and uncontrolla-ble spirits (to say nothing of scatological references todigestion). The most skilled inventor of this metaphoricalabuse, and Priestley’s most eminent public antagonist, wasthe Irish politician Edmund Burke.

In his enormously influential Reflections on the Revolu-tion in France (1790), Burke stressed the superiority ofBritish customs, built up from practical experience, to therational system imposed from above on the French people.Burke’s opponents criticized him for using colourful, mock-ing imagery, but it made good copy for attracting popular

d. doi:10.1016/j.endeavour.2010.07.005

[(Figure_1)TD$FIG]

Figure 1. DOCTER PHLOGISTON, The PRIESTLEY politician or the Political priest.

Anonymous caricature, 1791.

[(Figure_2)TD$FIG]

Figure 2. The Discoverer of Oxygen: Statue of Joseph Priestley, Birmingham, 1874.

Illustrated London News, Aug 8, 1874, p. 129.

Feature Endeavour Vol.34 No.3 85

audiences. Burke and Priestley had once been friends, butas their political paths diverged, the radical chemistbecame a favourite target, and around thirty caricaturesof Priestley appeared between 1790 and 1794.3 Priestley’sposition was not as straightforward as his enemies madeout. ‘No Popery’ was adopted as a campaign slogan by theBirmingham rioters – but it was also Priestley’s own; andthe French systematic, quantitative methodology deploredby Burke was very different from Priestley’s empirical,chance-driven approach.

A century later, Victorian industrialists converted thisone-time villain into a local hero by erecting a twenty-foothigh marble statue in front of Birmingham Town Hall(Figure 2). The tradition of commemorating anniversarieswas a nineteenth-century invention, and this was one ofthe earliest birthday tributes to an important scientificevent – Priestley’s isolation of oxygen in 1774. ThomasHenry Huxley travelled up from London for the unveilingceremony, and gave a speech before going on to the GreatWestern Hotel for lunch with the city’s dignitaries. These

3 Golinski, J. (1992) Science as Public Culture: Chemistry and Enlightenment inBritain, 1760–1820 (Cambridge: Cambridge University Press), pp. 176–87.

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Birmingham celebrations hit the national press, and aheadline in the Illustrated London News proclaimedPriestley to be ‘The Discoverer of Oxygen’.

Priestley always felt that Lavoisier had breached thecodes of ethical conduct by appropriating his results, andhe would have been furious to learn that he was beingremembered for his rival’s success. The sculptor gavePriestley a small burning lens in his right hand, althoughthe one he actually used was a foot across and had

86 Feature Endeavour Vol.34 No.3

disappeared the night his laboratory was demolished. Inhis left hand, Priestley holds a test-tube to collect thesubstance given off by a powder subjected to the concen-trated heat of the sun’s rays. One way of describing this

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experiment is to say that oxygen gas is released by mer-curic oxide. In Priestley’s opinion, it made more sense tobelieve that God had enabled English chemists to producelife-giving dephlogisticated air from red calx of mercury.