ganize the rescue
work. I've been doing that for the last year."

"I should think that was bully!" exclaimed Eric. "But how do you do it?"

"It's easy enough to start." The young fellow laughed. "I'm a regular
rescue 'fan' now. I usually get two or three teams together and have a
match. Talk about your kids on a baseball diamond in a vacant lot! Those
miners' rescue teams have the youngsters skinned a mile for excitement
when there's a rival test."

"But I don't see how you could have a fire-rescue match," said Eric,
puzzled, "you can't set a mine on fire just to have a drill!"

"Scarcely! At least, you can't set a whole mine on fire. Once in a
while, though, you can use an old mine shaft. But we generally do it in
the field. There the entries and rooms are outlined with ropes on
stakes. Across the entrances of these supposed rooms crossbars are laid,
just the height of a mine gallery.

"The contest is to find out how good the men are, individually, and to
teach them team work. Each man has a breathing apparatus, and a safety
and electric lamp, while each crew has a canary bird."

"A what?"

"A canary bird!"

"What kind of a machine is that?" asked Eric, thinking the other was
referring to some name for a piece of rescue apparatus.

"A canary bird? It's a yellow machine with feathers, and sings," said
Ed, laughing.

"You mean a real canary bird?"

"Yes, a live one."

"But what the crickets do they need a canary bird for?"

"To give them a pointer as to when the air is bad. You see, Eric,
there's all sorts of different kinds of poisonous gases in coal mines.
Some you can spot right off, but there's others you can't."

"I thought gas was just gas," Eric answered, "'damp,' don't they call
it?"

"There's several different 'damps.' Take 'fire damp' or just plain 'gas'
as the miners call it. That's really methane, marsh gas, the same stuff
that makes the will-o'-the-wisp you can see dancing around over a marsh.
It'll explode, all right, but there's got to be a lot of it around
before much damage'll be done. 'Fire damp' is like a rattlesnake, he's a
gentleman."

"How do you mean?" queried the boy.

"Well, just the same way that a rattler'll never strike before giving
you warning, 'fire damp' always gives you a chance ahead of time."

"How?"

"You know every miner carries a safety lamp?"

"Yes."

"'Fire damp' makes a sort of little cap over the flame of the lamp, like
a small sugar-loaf hat. As soon