Note 2. Afterdamp is the poisonous gas which forms after a mine explosion, mostly carbon monoxide. In the Rolling Mill disaster, only 7 of the 114 men were killed by the explosion, the rest by afterdamp. Note 3. New York Times, July 11, 1902, P. 1, "Check" referes to a metal tak pinned to the shirt of each miner which served to identify him.