Then all of them saw what the first discoverer had attempted to describe.  They stared as though fascinated.  Truly Horatio had said well when he spoke of the odd movements of the mysterious light; for it moved swiftly up and down, then sideways, and in eccentric circles, after which it vanished as suddenly as it had come into being.

Some of the boys sighed, as though being wakened from a dream.  Horatio, of course, was full of deepest gratification, since he had detected a skeptical air in the actions of Thad and Owen, which seemed to place him in the light of one who “saw things where none existed.”

“There, didn’t I tell you?” he exclaimed, triumphantly.  “And, say, wasn’t that—­eh, party, whoever he might be, making some sort of telegraphic signals with his old lantern or torch?”

“Hugh, what do you think?” demanded Thad.  “You’re up in all that kind of wigwag signal work, and perhaps now you could tell what it means.”

“I lost some of it, I’m sorry to say, fellows,” observed Hugh, gravely; “but all the same I caught enough to tell me that waving of a light was meant as a signal message, though who sent it, and to whom, is all a mystery.”

“But could you make out enough of the message, Hugh, to give you any idea what it stood for?” persisted Thad.

“Yes, I believe I did,” the other admitted, solemnly, so that each of his chums bent closer to catch the next words that fell from his lips.  “I’m certain it spelled out the word ‘help,’ for one; and I thought another was ’quick’!”

“Oh! what do you think of that?” gasped Horatio.

“The mystery deepens,” added Owen, dramatically, just as he had probably been accustomed to reading in some story of excitement.

“Of course,” continued Hugh, immediately, “we’ve got to take a look around that same old quarry, and see what’s going on.  Somebody’s holding the fort there, even if it is said to be deserted.  Who and what he can be, of course, remains to be seen; but I’m not taking a bit of stock in those old wives’ yarns about a ghost, remember, Horatio.”

“Then we’ll have to leave the car on the road, won’t we, Hugh, when we tackle this big job?” questioned Owen.

“Of course; and since I marked the best spot where anyone could make their way along to the face of the quarry, we must start up again, and keep moving till we strike that place.”

“But, Hugh, do you think the—­er—­party making those signals with a light could have noticed our illumination, and that message was meant for us?” Horatio went on to ask, solicitously.

“I’m not prepared to say,” he was told, “though I don’t see how anybody with eyes could miss discovering us coming along.  And, besides, the old car makes plenty of noise in the bargain, to attract attention.  So it looks as if he did know, and was trying to talk to us.”

All this only added to the thrill that was forever passing through each and every member of the night expedition.  It would be manifestly impossible to describe their mixed feelings as they advanced slowly along the rough road so long abandoned to nature.  A dozen times Horatio believed he heard cries; why, it seemed as though the air must be filled with uncanny sounds, for his lively imagination was working at race-horse speed just then.