English chemist and minister · 1733–1804
Joseph Priestley
Joseph Priestley is the best-known discoverer of oxygen. A dissenting minister and political radical, he also invented carbonated water and isolated more gases than anyone of his time.
How Oxygen was found
On 1 August 1774 Priestley used a large burning lens to focus sunlight on mercuric oxide. A gas came off in which a candle burned with a dazzling flame. A mouse sealed in it lived far longer than in ordinary air, and when he breathed it himself he found it light and easy.
He called it “dephlogisticated air”. In Paris that October he described it to Antoine Lavoisier, who realised what it meant and named it oxygen. Scheele had made it earlier but published later, so the two share the credit.
Shared the credit
The discovery is credited jointly to these scientists.
Life and career
Born 1733 · Died 1804
Priestley was born near Birstall, Yorkshire, and became a minister and teacher. He began chemistry while living next to a brewery in Leeds, where he learned to dissolve the gas from fermenting vats in water, inventing soda water.
His support for the American and French revolutions made him enemies. In 1791 a mob in Birmingham burned his house, laboratory and chapel. In 1794 he emigrated to Pennsylvania, where he died.
Also known for
- Invented carbonated water
- Discovered that plants restore air that animals have used
- Isolated ammonia, nitrous oxide and hydrogen chloride gases
Discovered in the same era
Other elements identified within ten years of 1774.