Discovery of Oxygen by Joseph Priestley
- When
- 1771–1775
- Where
- Wiltshire, England; Uppsala, Sweden; Unknown
- Episodes
- 3
Joseph Priestley isolated oxygen in Wiltshire in 1774, naming it dephlogisticated air. Carl Wilhelm Scheele had produced the gas earlier in 1771–1772 but published later. Priestley's 1775 publication preceded Scheele's 1777 account, establishing his priority in the scientific record.
Episodes
- Scheele's Prior Production
Scheele produces oxygen by heating mercuric oxide and nitrates before Priestley.
- Isolation of Dephlogisticated Air
Priestley isolates oxygen from mercuric oxide using sunlight in Wiltshire.
- Publication of Findings
Priestley publishes his discovery in 1775, establishing his priority over Scheele.
Background and detail
The Discovery. On 1 August 1774, Priestley focused sunlight on mercuric oxide, liberating a gas he called dephlogisticated air. He noted the gas made his breathing feel light and easy. Although he isolated the gas in August 1774, he did not immediately pursue the matter due to an upcoming European tour with Lord Shelburne.
Priority and Publication. Carl Wilhelm Scheele had produced oxygen by heating mercuric oxide in 1771–1772 but did not publish until 1777. After reading about Priestley's work in 1775, Scheele published in 1777, calling the gas "fire air" because it was then the only known agent to support combustion. Priestley published his findings in 1775, preceding Scheele's account.
People involved
- Joseph Priestley · English chemist and discoverer of oxygen
- Carl Wilhelm Scheele · Swedish pharmacist who independently produced oxygen
Sources
- Oxygen Wikipedia, revision of 2026-09-21
- Joseph Priestley Wikipedia, revision of 2026-09-16
Machine-drafted from the cited Wikipedia passages and checked by a reviewing model, not by a human editor. Every passage cites the revision it was written from; dates and places follow those passages.