"It's tough on the bird," was Anton's sympathetic comment.
"Not especially! As soon as a bird begins to show collapse, it is taken back to the open air and is as frisky and lively as ever in five minutes. But its value as a warning signal is enormous, for it tells rescue parties or investigating parties when to put on gas masks or breathing apparatus containing oxygen. In a well-ventilated mine, however, where high explosive is used and handled by experienced men, there's not likely to be much danger from white damp.
"Stink damp is rare but can sometimes be dangerous. Generally, a fellow is warned away, because of the smell—which is just like rotten eggs. The worst part of stink damp is that it smells the worst when there's only a little of it. When there's so much of it around as to be deadly, it doesn't smell any worse. You get small quantities of it, sometimes, in blasting, but generally hydrogen sulphide or stink damp is found after a mine fire or an explosion. Rescue parties generally carry a cage of mice as well as one of canaries."
"With the same idea?" queried Anton.
"Exactly. As little as a tenth of one per cent. of stink damp makes a mouse sprawl on his belly, his legs don't seem strong enough to hold him up; while, in the same air, a canary doesn't suffer a bit.
"The only real danger in stink damp is when there's water in the mine, for example when, after a fire, a lot of water has been pumped down into the workings to put the fire out. Water absorbs stink damp very easily and gives it up equally easily when stirred. So, if a member of a rescue party puts his foot in a puddle of water where there has been stink damp around, so much of the gas may suddenly come up in his face as to topple him over.
"But you can see, Anton, that most of the gas troubles in a mine come from the blasting. That's why, nowadays, the miners who get out the coal seldom or never fire the shots. Experienced men, trained especially for that work, are used. After a miner has undercut the coal, the shot-firer comes. He tests for gas before he begins work, bores a deep hole in the coal with a drill, tests for gas again in case he should have tapped a leak in the seam, cleans out the hole, sends the miner for the box of explosive—which is kept thirty or forty yards away from the face where the coal is being cut—and prepares the charge with a detonater which he carries in a box over his shoulder. The miner never touches either the explosive or the detonater. Then the shot-firer puts the primed charge in the hole, jams the hole full of clay with a wooden tamper—a steel bar might cause a spark and a premature explosion—tests for gas again, connects the electric wires from a portable battery around the rib corner, fires the shot, returns to the face and tests for gas again. Then, and not until then, does the miner begin to dig the coal. That way, every one in the mine is safe."
"Yes," growled the old miner, "and the shot-firer doesn't dig any coal, nor do any hard work, an' gets paid more'n we do."
"He knows more than you do," Clem responded, "and he gets better pay because his experience and prudence is worth a lot of money to the mine. Just think what an explosion costs—to say nothing of the risk of lives being lost! And you won't find experienced shot-firers or mine-managers talking about gas sprites, Otto!"
"Better for 'em if they did!" the old man warned. "For I'm sayin' to you again, what I said before—the spirits o' the mine is gettin' hungry for blood!"