he balloon.

"His mind seems all right now and he is well as any man could be, but he
either cannot or will not tell us a thing of his life with the Orientals
up there at the mines," said Dave. "There are some things we would all
like to know. Strange case, I'd call it."

"Yes, but there have been stranger. Say!" Johnny slapped him on the
shoulder. "You bring him around to headquarters to-night. I've got an
idea."

"Righto. We'll be there. So long till then."

When Dave arrived with the professor, he found that the stage had been set
for a moving-picture show. He was glad of that; it had been months since
he had seen one. He was hardly prepared, however, for the type of show it
was to be.

The room was darkened. Beside him, sat the professor. There came the
peculiar snap-snap of the carbons as the power came on. The next instant a
dazzling light fell upon the screen, and out into that light there moved a
half-score of little yellow men. Some were working industriously at a
machine which cut cubes of earth from the bank before them. Others were
carrying the cubes away and piling them.

Professor Todd moved uneasily. He put his hands to his eyes, as if to shut
out the scene. Then unexpectedly he cried out, as if in pain:

"My head! My head! He struck me."

"Who struck you?"

Dave looked about. There was no one near them.

"The yellow man; he struck me," cried the professor. Then he covered his
face with his hands and his body swayed back and forth with suppressed
emotion.

Johnny moved silently toward them.

"It's coming back to him. When he regains control of himself, he will know
everything. It was the flash of light and the familiar scene that did it.
Of course, you know that is the film he sent out to us when he was a
prisoner in the mine."

What Johnny said was quite true. When the man was again in the cool
out-of-doors, he was able to give a full account of his life with the
Orientals. They had made him prisoner because they feared to have him at
large. Other white men might appear, as indeed they had, and he might
reveal their plans. He had known in a vague sort of way that some
mysterious deathtrap had been set in Mine No. 1, and when, through a crack
in the wall to his prison, he saw the white men arrive, he determined to
attempt to warn them. This he did by singing songs to the Orientals and,
at the same time, making phonographic records to be sent rolling down the
hill later.

"But you don't