Nitrous oxide was discovered in 1772 by Joseph Priestley. Humphry Davy, inventor of the miner's lamp, documented it as a recreational drug after testing it on the poet Coleridge.

In 1882, the American philosopher William James praised its ability to provide "ultimate truth" to a user, in a powerful spiritual and mystical experience. But, sadly, the after-effects of nitrous oxide proved similar to other recreational drugs: the memory of the experience did not linger.

Nitrous oxide has more oxygen than atmospheric air, so it helps an engine burn more fuel, boosting its power. It is also used to enhance the performance of the internal combustion engine and to propel rockets and force whipped cream out of a dispenser.

It is also an emergency anaesthetic and an analgesic, most often used in childbirth. It was used extensively for a time by dentists.

Harmless and really, really funny