"Didn't your arm hurt like blazes?"

"I suppose it did, but I don't remember noticing it much at the time. I got back to the mine entrance and steered another gang to where the cave-in had occurred. But what do you suppose I found when we got there?"

"What?" called Eric, excitedly.

"My men were poisoned!"

"How?"

"White damp."

"You mean they were dead?" exclaimed the boy, horror-stricken.

"No, they were all at work," said the other, "but they were pickaxing the rock in a listless sort of way that I recognized at once. You see, I'd done quite a bit of reading along those lines—Dad was so keen on it—so I could tell at once that they'd had a dose of carbon monoxide, and a bad dose at that.

"'Come back, boys!' I cried. 'Come back! The place is full of 'white damp'!

"But they were a plucky lot of fellows. Their comrades were entombed on the other side of the cave-in and they wouldn't quit. And all the while they were breathing in the fumes."