“19th century coal miners would traditionally take canaries in cages down into the mine with them. The birds would act as an early warning system for carbon monoxide gas. When the canary stopped singing the miner would know that he had to escape the
“19th century coal miners would traditionally take canaries in cages down into the mine with them. The birds would act as an early warning system for carbon monoxide gas. When the canary stopped singing the miner would know that he had to escape the