Coal mine canaries retiredIn 1986, the BBC reported that the British government planned to replace about 200 canaries used in mining pits with modern electronic gas detectors. From 1987, as new technology was gradually phased in, the birds were retired. Live canaries carried in small cages had been used in pits since 1911 to warn of the presence of carbon monoxide, a deadly but colourless, tasteless and odourless gas. John Scott Haldane researched the practice. A small animal with faster metabolism would be more quickly affected by noxious fumes than a human. Canaries were preferred over, say, mice, because they gave an early warning easier to detect. An affected bird would stop chirping, have trouble breathing, sway on its perch and (with trimmed claws) noticeably fall. (Prompt oxygen could be used revive it, for further use.) Or die.«[Image: miner holding up a canary in a cage.] |
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