“What is that?” inquired Mr. Jenks.

“I think we should go up higher.  In my opinion the cave is near the top of some peak; isn’t it, Mr. Jenks?”

“I have that impression, though, as you know, I never saw the outside of it.  Still, it might not be a bad idea to ascend some of these peaks.”

Following this suggestion, they laid their trail more toward the sky, and that night found them encamped several thousand feet above the sea-level.  It was quite cool, and the campfire was a big one about which they sat after supper, talking of many things.

Tom did not sleep well that night.  He tossed from side to side on the bed of boughs, and once or twice got up to replenish the fire, which had burned low.  His companions were in deep slumber.

“I wonder what time it is?” mused Tom, when he had been up the third time to throw wood on the blaze.  “Must be near morning.”  He looked at his watch, and was somewhat startled to see that it was only a little after twelve.  Somehow it seemed much later.

As he was putting the timepiece back into his pocket the lad looked around at the dark and gloomy mountains, amid which they were encamped.  As his gaze wandered toward the peak of the one on the side of which the tent was pitched, he gave a start of surprise.

For, coming down a place where, that afternoon, Tom had noticed a sort of indefinite trail was a figure in white.  A tall, waving figure, which swayed this way and that—­a figure which halted and then came on again.

“I wonder—­I wonder if that can be a wisp of fog?” mused the young inventor.  He rubbed his eyes, thinking it might be a swirling of the night mist or a defect of vision.  Then, as he saw more plainly, he noticed the thing in white rushing toward him.

“It’s the phantom—­the phantom!” cried Tom, aloud.  “It’s the thing the miner saw!  We’re on Phantom Mountain now!”

CHAPTER XIV—­WARNED BACK

Tom’s cries awakened the sleepers in the tent.  Mr. Damon was the first to rush out.

“Bless my nightcap, Tom!” he cried.  “What is it?  What has happened?  Are we attacked by a mountain lion?”

For answer the young inventor pointed up the mountain, to where, in the dim light from a crescent moon, there stood boldly revealed, the figure in white.

“Bless—­bless my very existence!” cried the odd man.  “What is it, Tom?”

“The phantom,” was the quiet answer.  “Watch it, and see what it does.”

By this time Mr. Jenks and Mr. Parker had joined Tom and Mr. Damon.  The four diamond seekers stood gazing at the apparition.  And, as they looked, the thing in white, seemingly too tall for any human being, slid slowly forward, with a gliding motion.  Then it raised its long, white arms, and waved them threateningly at the adventurers.

“It’s motioning us to go back,” said Mr. Parker in an awed whisper.  “It doesn’t want us to go any farther.”