, and keep trespassers out
during the day, for fear of raiders.

"The first night in camp on the mountains, Mike never rested a minute,
but moved silently from one place to another, with senses keyed for some
sign of the rascals. However, that first night passed quietly away. His
extra men spent the evening in smoking and playing cards, then they
rolled up in their blankets and snored peacefully the night through.

"The next day Mike smiled to himself when the men laughed at his
suspicions. They were so far from any settlement and the mountains were
so great and silent, that it gave them confidence in the peace and good
will with all men.

"The second night the men were again playing cards near the camp-fire.
Mike sat on the ledge in front of the cave with the hound stretched out
on a slab of rock at his feet. The giant wooden flume could be faintly
discerned, through the smoke of the fire and from the pipes of the men,
not twenty feet away from the engines that worked it.

"Suddenly the hound lifted his head and pointed his ears. Mike leaned
forward with face turned towards the flume, listening. Then he laid his
pipe down on the rock and crawled away upon his hands and knees, followed
closely by the hound.

"Do you remember the giant flume we planned to carry off the water of the
river that flowed underground; the one into which Nolla and you dropped
the torch the day you found the cave?"

Polly silently signified that she remembered, and Tom continued: "Well,
we used that flume during the work of mining and washing trash from the
ore, but at night, when there was no need for the water to pour through
it, we turned the current down the other way on the opposite side of the
mountain.

"Mike crept silently across the ledge and peered far down into the black
chasm below, to ascertain if the suspicious sounds came from that pit.
But the dog crawled noiselessly across the ledge to the flume and there
he stood with tense nerves. His ears were erect and his tail was standing
out straight behind him, as he stood and glared at the wooden flume.

"As the dog was so well-trained, Mike did not doubt his instinct, but
crept over to his side and there waited and listened.

"Had he not been absolutely quiet, the faint sound of something moving
inside that flume would have been lost on the outside. But Mike was as
keen a hunter as his dog, and they both sensed that something very
foreign to water was passing through that flu