A Pictorial Walk Through
the 20th Century
Canaries
the 20th Century
Canaries
Small cage with canary bird used in testing for carbon monoxide gas. Hollinger Mine, Timmons, Ontario, Canada. Mine Fire 02/10/1928 According to tests conducted by the Bureau of Mines, canaries were preferred over mice to alert coal miners to the presence of carbon monoxide underground, because canaries more visibly demonstrated signs of distress in the presence of small quantities of the noxious gas. For instance, when consumed by the effects of carbon monoxide, a canary would sway noticeably on his perch before falling, a much better indicator of danger than the limited struggle and squatting, extended posture a mouse might assume.
|
