Gas holder, zinc, Europe, c.1900

Before 1868, nitrous oxide had to be made as required and puchsed in bladders or bags. gas holders were used to collect the gas as it was made - often by heating ammonium nitrate. After 1868, nitrous oxide was available in cylinders.

Nitrous oxide, also known as laughing gas, is a mild anaesthetic and was first used, albeit unsuccessfully, in a dental surgery by Horace Wells in 1844.