Description up to 4000 characters. This is about 1200.
When Joseph Black was studying the properties of carbon dioxide, he found that a candle would not burn in it. When a candle was burned in a closed container of air, the candle would go out eventually, and the remaining air would not support a flame. This was normal, but when the carbon dioxide (caused by the candle) was absorbed by chemicals, some air was not absorbed. The air that remained did not support a flame.
He turned this problem over to his student at the time, Daniel Rutherford. Rutherford kept a mouse in a space with a confined quality of air until it died. Then, he burned a candle in the remaining air until it went out. Afterwards, he burned phosphorus in that, until it would not burn. Then the air was passed through a carbon dioxide absorbing solution. The remaining 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” or “phlogisticated 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.