Joseph Priestley in 1772
Liughing Gas or Nitrous oxide is a chemical compound with the formula N2O. At room temperature, it is a colorless, odorless non-flammable gas, with a slightly sweet taste. It is used in surgery and dentistry for its anaesthetic and analgesic effects. It is known as "laughing gas" due to the euphoric effects of inhaling it, a property that has led to its recreational use as a dissociative anaesthetic.
It was discovered by English natural philosopher and chemist Joseph Priestley in 1772, who called it phlogisticated nitrous air. Priestley published his discovery in the book Experiments and Observations on Different Kinds of Air (1775), where he described how to produce the preparation of "nitrous air diminished", by heating iron filings dampened with nitric acid.