Discovered: Nitrogen
Daniel Rutherford FRSE FRCPE FLS FSA was a Scottish physician, chemist and botanist who is known for the isolation of nitrogen in 1772.
Daniel Rutherford was born in Edinburgh to Dr John Rutherford. He studied medicine at the University of Edinburgh under William Cullen and Joseph Black. Rutherford obtained his MD in 1772. His dissertation, titled “De aere fixo dicto aut mephitico,” established a distinction between carbonic acid gas and nitrogen. Rutherford is most famous for his discovery of the isolation of nitrogen in his inaugural dissertation.Rutherford’s M.D. the dissertation, dated 12 September 1772, was devoted mainly to the discoveries regarding the gas that Black had called “fixed air” (carbon dioxide), but which Rutherford preferred to call “mephitic air”. This is the earliest published account of the awareness of a gas (nitrogen) that, although unable to support life and combustion, was clearly not Black’s “fixed air.”Rutherford discovered nitrogen by the isolation of the particle in 1772.] When Joseph Black was studying the properties of carbon dioxide, he found that a candle would not burn in it. Black turned this problem over to his student at the time, Rutherford. Rutherford kept a mouse in a space with a confined quantity of air until it died. Then, he burned a candle in the remaining air until it went out. Afterwards, he burned phosphorus in it, until it would not burn. Then the air was passed through a carbon dioxide absorbing solution. The remaining component of the air did not support combustion, and a mouse could not live in it.
Rutherford called the gas (which we now know would have consisted primarily of nitrogen) “noxious air”. Rutherford reported the experiment in 1772. He and Black were convinced of the validity of the phlogiston theory, so they explained their results in terms of it.
After the publication of his dissertation and completion of studies, Rutherford travelled to France in 1773 and Italy. Rutherford returned to Edinburgh in 1775 where he set up a private practice. In 1786, Rutherford was appointed Professor of Botany and keeper of the Royal Botanic Gardens. In 1791, Rutherford succeeded Henry Cullen as physician in ordinary to the Royal Infirmary where he delivered clinical lectures in tandem with Andrew Duncan and Francis Home. Furthermore, Rutherford was the first Professor of Practice of Physics at the University of Edinburgh and played a significant role in the development of clinical teaching at the university’s medical school.