Portrait of British scientist Joseph Priestley by Ellen Sharples (1769-1849). He is largely credited as the discoverer of oxygen having isolated the gas in 1774.

Portrait of British scientist Joseph Priestley by Ellen Sharples (1769-1849). He is largely credited as the discoverer of oxygen having isolated the gas in 1774.

Portrait of British scientist Joseph Priestley by Ellen Sharples (1769-1849). He is largely credited as the discoverer of oxygen having isolated the gas in 1774.