Canaries were used to test for carbon monoxide and methane from 1911 to 1987 as they are highly sensitive to changes in air quality. As soon as the bird became distressed the miner would retreat and revive the bird if necessary.
Blog articles will only appear in the language they are provided in by the author.
Yn yr iaith y’u hysgrifennwyd gan yr awdur yn unig y bydd yr erthyglau blog yn ymddangos.
