into that black water until I have to. If a rope or something should
twine around my legs while I was in there, I'd drop dead with fright!
Besides," he went on, "the chances are that Canfield will get the
pumps going before long now."

The boys waited for a long half hour, during which time the water rose
steadily. It seemed certain that the mine was about to be flooded
throughout all the lower levels.

"Tommy and Sandy may have bumped into just such a situation as this,"
Will said, as he pushed the boat from side to side in the hope of
coming upon some exit from the place.

"Serves 'em good and right!" exclaimed George.

Will chuckled to himself and held up a wet hand high up toward the
roof of the chamber or passage.

"There's a current of air here!" he said.

"Then we won't smother to dead!" George grunted.

"And, look here," Will continued, as the boat bumped into a pyramid of
shale which had been thrown up to within a few inches of the roof,
"some one has been building this hill of refuse and using it for a
refuge!"

"It does look that way," George agreed. "That shows that, at some
time the water must have ascended to the very top of the wall. We may
have to climb up there ourselves in order to keep from getting our