Nitrous oxide has been used for anaesthesia in dentistry since December 1844, where Horace Wells made the first 12–15 dental operations with the gas in Hartford. Its debut as a generally accepted method, however, came in 1863, when Gardner Quincy Colton introduced it more broadly at all the Colton Dental Association clinics, that he founded in New Haven and New York City. Hospitals administer nitrous oxide as one of the anaesthetic drugs delivered by anaesthetic machines. Nitrous oxide is a weak general anaesthetic, and so is generally not used alone in general anaesthesia. In general anaesthesia it is used as a carrier gas with oxygen for more powerful general anaesthetic drugs.Medium size empty blue coloured cylinder with rounded base and painted white neck once containing Nitrous Oxide. A large blue on white diamond shaped label is adhered onto the main cylinder body.Printed on manufacturer's label: 'CIG [logo] / [blank weights table] / DRY / NITROUS OXIDE / C.I.G. (Victoria) PTY. LTD. / 50 LA TROBE STREET, MELBOURNE C3 / Telephones: FJ 6681 / FJ 4164 / USE NO OIL / OR GREASE'nitrous oxide, dental anaesthesia, dental anesthesia, gardner quincy colton, colton dental association