You can’t say it was invented because it was always around, so you’d have to give the guy credit for discovering it – nitrous oxide.  The man’s name was Joseph Priestly who was working with various gases on the theory they could be used to treat medical problems or even cure diseases and this was way back in 1772.  Some doctors bought into it and in the case of nitrous oxide they would let patients inhale some of it, it would make them happy and it took on the nickname “laughing gas.”

 There was a suggestion that it could be used as an anesthetic, but doctors didn’t want to be responsible for the side effects because they didn’t have a way to control how it would affect various patients.  A slower heartbeat and weak pulse was their main concern.

Through a good portion of the 1800’s nitrous oxide was just a novelty.  They called it “fun gas” at some carnivals.  Watching the way it would affect some people, a guy that ran one of these carnival booths thought it could be used medically if it was done right.  Gardner Colton opened up what he called “painless” dental offices using nitrous oxide.

Dentists still use it today mixed with other gases for general anesthesia.

 Nitrous oxide has other applications too as a propellant in rocket engines, it’s used in racing engines to create more power, it’s a propellant in aerosol cans – whipped cream for example and it’s also an ingredient in the system that inflates car airbags.

SOURCE: Wikipedia.com