"The thieves are getting bold!" was Dick Munson's comment.
"Seems to me they not only are getting, but have been for some time," laughed the Professor. "The condition of my feet proves that."
The Number 2 section to which the superintendent's informant had referred, was a quarry mine, off among the mountains in the vicinity of the red rock that had attracted Tad's attention as they neared the camp. He made a sudden resolve to visit the place on the following day.
Borrowing a pony next morning, and without telling anyone where he was going, Tad rode away with the Ruby Mountain as his destination. The trail was an easy one to follow and, besides, he had so recently been over it that he would be able to find his way there and back.
Just why he felt such a keen interest in the place the lad did not know. Perhaps it was that the miners had thrown such an air of mystery about it in speaking of the red rock. Aside from its color there was nothing about the pile of stone to distinguish it from almost any other rocky formation in the Ozark range, unless it were the slight resemblance that it bore to the form of a church. The lad had observed this the first time he saw it.
After riding around the pile, Tad dismounted, and, tethering his pony, proceeded to examine the place more carefully.
The rock was rough and uneven, with little spires running up here and there. The lowest of these was a considerable distance from the ground.
"I'd like to climb up there if I knew how," decided the boy, looking for an advantageous place to make the attempt.
"I have it. I know what I'll do. I'll rope the rock."
Tad laughed gayly at the thought as he ran back to where he had tethered the pony in the shrubbery. Tom Phipps had seen to it that the outfit was fully equipped, having added a lariat, because Tad had jokingly inquired where this necessary equipment was.
"Glad I happened to think of that. I'll never ride out without a rope again, even if it's up and down Main Street in Chillicothe."
Fetching the rawhide rope he skilfully cast it up and over the pinnacle of rock nearest to him. It was now a comparatively easy matter to climb by going hand over hand up the rope and bracing his feet against the side of the rock at the same time.
Once having reached the point where the rope had been fastened, the rest of the way was less rough.
The lad sat down to look about him, noting that the formation was a peculiar one, and that the reddish shade of the rock disappeared when one came into close contact with it.
"Why, it's just a plain, ordinary pile of stone," laughed Tad. "The idea that there could be anything mysterious about it! I'll climb up to the top and see if there is anything more interesting there."
There were frequent narrow crevices that the young explorer discovered on the way up. These appeared to reach down to a considerable depth, but having no weight to attach to the end of his rope he could not sound the depth with any degree of certainty. One of these crevices was large enough to admit his body.
The place fascinated him.
"I'm coming out here prepared to go down in that hole and investigate it," he said to himself. "I'll bring the boys--no, I won't either. I'll explore it all myself and maybe I'll find out something."
The lad was coiling his rope, preparing to descend when a low chuckle caused him to pause in sudden surprise. Startled, the boy looked about him. He was alone as he had been before.
"That's strange. I was sure I heard some one. Sounded as if it were right here beside me. I must have been wrong of course. Believe I'm losing my grit. After all the shaking up my nerves have had on this trip--"
"Hello!"
This time there could be no doubt. It was a human voice beyond all question.
"Hello," answered Tad, when, an instant later, he had in a measure mastered his surprise. "Where are you?"
"Guess."
"I can't. I am not a good hand at guessing."
Getting to his feet the lad began searching about, peering into crevices, looking over the edge of the cliff, becoming more and more perplexed and mystified as the moments passed.
"No, I can't find you. Come out and show yourself, whoever you are," he commanded, with some impatience.
A low, mocking laugh answered Tad's irritated command, yet the owner of the voice still remained hidden.
"Who are you, anyway? I know you are a girl, but--"
"But what?" tantalized the voice.
"That's all I know about it, and all I shall at the present rate. Come on, it's not fair to expect me to talk with you when I can't see you--"
"Aren't you afraid of ghosts, boy--"
"Ghosts!"
Tad uttered the word in a startled voice.
"Wha--what ghosts?"
"Yes."
"No, I'm not," he answered sharply. "But if it were night I think I'd run. Pshaw! you're no more ghost than I am. You're just a girl and I am going to find out where you are right now."
Acting upon his resolution, Tad began searching for the owner of the voice again. But when he had crawled to one side of the rock, the voice appeared to be on the other, where he had just been.
After a time Tad gave it up. He no longer heard the mysterious voice, so he clambered down, and after examining the rock from the ground once more, mounted his pony for return to camp.
Arriving there, his companions wanted to know where he had been, but Tad managed to evade their question without giving them a direct answer.
He was determined to return on the following day, when he would go about finding the owner of the mysterious voice in a different way.
When Tom Phipps came in from work, Tad drew him aside at the first opportunity.
"I've been over to the Ruby Mountain to-day, but please don't tell anyone."
"Saw something, did you?" laughed the assistant superintendent.
"No, that's the trouble. I didn't."
"What happened then?"
"I did not see, but I heard." Tad then related all that had occurred on his visit to the strange mountain.
Phipps did not laugh. He remained silent and thoughtful for some moments.
"That's strange. A miner prospecting there came back with a similar story a few months ago. Nobody believed him, though many strange things are said to have happened in the vicinity of that rock."
"What?"
"That's the trouble. One cannot get them to tell what they saw. You have come the nearest to doing so."
"Only I just missed it by about a mile," laughed Tad. "But you do not think it's--how shall I say it?"
Phipps bent a keen glance on the young man. "You mean through any supernatural agency?"
Tad nodded.
"That's what I wanted to say, but didn't know just how to put it."
"No, I am too practical to believe any such trash as that. My idea is that some one of a humorous turn of mind is trying to play tricks on people. You say it was a girl's voice?"
"Yes."
"That's strange. I'm going to look into that."
"Let's you and I go over there together to to-morrow, then," urged Tad enthusiastically.
"I'll do it--that is, if there is nothing on hand to detain me. I'll let you know later whether it will be possible or not."
"Very well. I have been thinking--wondering whether--"
Tad hesitated.
"Wondering what?"
"Whether that rock has anything to do with so many horses and things being stolen in the range."
Tom Phipps laughed heartily.
"I never thought of it in that light. Don't see how a rock could possibly have any connection with it. Guess we shall have to look for something more human than a pile of stone."
It was decided, therefore, that on the morrow the two should visit the Ruby Mountain, when they would make a careful examination of the place in an effort to solve the mystery.
But they were destined to delay this trip for some time, and to pass through some exciting experiences before they solved the mystery of the Ruby Mountain.