“The chemists call it light carbureted hydrogen; most people know it as ‘marsh-gas,’ because you can see it bubbling up whenever you stir the water of a marsh; but the miner calls it ‘fire-damp.’ There’s a lot of it in coal, especially soft coal, and after every blast more or less of it is released. If the air-current is good, this is blown away before it can do any harm. If the ventilation is bad, the gas collects gradually at the top of a room. Pretty soon it will get low enough to touch the flame in one of the lamps, and then usually there is a big explosion which wrecks all that part of the mine. If there isn’t enough of it to explode, it catches fire and rolls back and forth across the roof, and if the miners aren’t burnt to death, they’re pretty likely to be suffocated by the after-damp.”
“That’s another word.”
“Yes; after-damp or choke-damp is only the miner’s word for the carbonic-acid gas generated by the combustion of fire-damp. It is heavier than atmospheric air, and so settles at once to the floor of the room. Two breaths of it will cause death, and the miner who has thrown himself on the floor to protect himself from the fire hasn’t much chance unless he gets up and out pretty quickly.”
Miss Andrews drew a long breath of dismay.
“And is that all?” she asked at last.
“Oh, no”; and the superintendent laughed at her tone. “There are other kinds. There is white-damp, more deadly than either of the others, but much less common; and even coal-dust itself forms a very violent explosive under certain conditions. The one great protection against them all is perfect ventilation—only mighty few things are perfect in this world, and mine ventilation isn’t one of them. But here I’m yawping away like a man on a lecture platform; aren’t you getting tired of listening?”
“No, indeed!” she answered warmly, and they went on along other entries, into other rooms. Everywhere the same nerve-straining, muscle-tearing toil was in progress; blast followed blast; the coal was carried away, out to daylight—the first daylight it had ever seen; everywhere was the rumble of the cars, the shouts of the driver-boys.
“So you have been through a coalmine,” said her guide, when he had brought them at last back to the entrance. “There’s not many women in this great country can say as much. And now I’ll have to leave you—Mr. Bayliss is a pretty fair guide for the open air. Will you ride down?”
“No, thank you,” she said. “We’d prefer to walk, I think. And sometime I’ll thank you properly for your kindness; just now I’m too dazed, too astonished by it all, to think clearly.”
“That’s all right,” he said, laughing. “I’ll bet I enjoyed it more than you did”; and waving his hand to them, he turned back into the mine.