Daniel Rutherford, Scottish chemist and physician, is best-known for his discovery of nitrogen, a chemical element of air that does not support combustion. He described oxygen as "vital air" and nitrogen as "phlogisticated air" or noxious air.
Early Life of Daniel Rutherford
Daniel Rutherford (November 3, 1749 – November 15, 1819), was born in Edinburgh, Scotland. He was educated at the University of Edinburgh where his father, John Rutherford, was a professor of medicine. Incidentally, he was also a maternal uncle of the famous poet, Sir Walter Scott.
In 1786, at the age of 37, he was appointed Regius Professor of Botany in Edinburgh. He later became the Keeper of the Royal Botanic Garden Edinburgh after the death of Professor John Hope. Rutherford held both posts until his death.
Discovery of Nitrogen
At that time, Joseph Black was a professor of Rutherford. Black was studying the properties of carbon dioxide, a gas that exists on earth consisting of two oxygen atoms bonded to a single carbon. Black found out that when a candle was burned in a closed container of air, the candle would eventually go out, and the remaining air would not support a flame. This result was normal, but when the carbon dioxide, caused by the candle, was absorbed by chemicals, some air was not absorbed. In other words, the air that remained did not support a flame.
Black turned this problem over to Rutherford. Under Rutherford's experiment, he kept a mouse in a space with a confined quality of air until it died. He then burned a candle in the remaining air until it went out. Afterwards, he burned phosphorus in it, until the burning stopped. The air was passed through a carbon dioxide absorbing solution. The test result was that the remaining air did not support combustion. The mouse could not live in it.
Phlogiston Theory
Rutherford called the gas noxious air or "phlogisticated air." Today, this gas is simply called nitrogen. He reported their findings in 1772. From their experiments, Rutherford and Black were convinced of the validity of the phlogiston theory, and therefore, results were explained according to this theory.
As mice breathed and combustion was created, phlogiston was given off and entered the air, along with the carbon dioxide. Later, when the carbon dioxide was absorbed, actually the air still contained phlogiston, and in fact, the air was saturated with it. This is the reason why candles and other objects would not burn in it.
Sources:
Ellyard, David. Who Discovered What When. Sydney: New Holland Publishers, 2005
McGovern, Una, editor. Chambers Biographical Dictionary. Edinburgh: Chambers Harrap, 2002
