Live canaries, which used to be carried down into coal mines as sentinels against firedamp, are not often stationed in modern chemical laboratories. Nevertheless, Dr. Harold Clayton Urey and his coworkers* at Columbia University have kept canaries within sniffing distance of their apparatus for months. Reason: the chemists were working with two deadly poisons, hydrogen cyanide (used in some U. S. States to execute condemned criminals) and sodium cyanide. If these began to leak from the apparatus, the sensitive little birds would collapse in time for the men to take action. Pacific, round-faced,...
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