He has historically been credited with the discovery of oxygen, having isolated it in its gaseous state, although Carl Wilhelm Scheele and Antoine Lavoisier also have strong claims to the discovery.
Ia dikenal luas sebagai penemu oksigen, yang diisolasi dalam keadaan gas, meskipun Carl Wilhelm Scheele dan Antoine Lavoisier turut memiliki klaim yang kuat terhadap penemuan tersebut.