Tom paid no attention. He had paused and was holding his lantern over the stream.

"Those four stones are in a pretty straight line," he said. "Would you say that was a ford?"

"Looks more like a Buick to me," said Garry, but he added, "They _are_ in a pretty straight line. I guess it's a flivver, all right."

"Look on that side," said Tom, to the others. "Do you see anything over there?"

He was looking carefully along the edge; of the water when Doc called suddenly,

"Come over here with your light, quick!"

Tom and Garry crossed, stepping from stone to stone, and presently all four were kneeling and examining in the lantern light one of those commonplace things which sometimes send a thrill over the discoverer-a human footprint. There upon that lonesome mountain, surrounded by the all but impenetrable forest, was that simple, half-obliterated but unmistakable token of a human presence. Tom thought he knew now how Robinson Crusoe felt when he found the footprint in the sand.

The exposed roots of a tree formed ridges in the hard bank, where footprints seemed quite impossible of detection, and it was in vain that the boys sought for others. Yet here was this one, and so plain as to show the criss-cross markings of a new sole.

"It's from a rubber boot," said Garry.

"There ought to be _some_ signs of others even if they're not as clear as this one," said Tom. "Maybe whoever was wearing that boot slipped off one of those stones and got it wet. That's why it printed, probably. Anyway, somebody crossed here and they were going up that way, that's sure."

They stood staring at the footprint, thoroughly sobered by its discovery.

They had penetrated into this rugged mountain in the hope of finding some one, but the remoteness and wildness of the place had grown upon them and the whole chaotic scene seemed so ill-a.s.sociated with the presence of a human being that now that they had actually found this silent token it almost shocked them.

"Maybe the wind was wrong before," said Tom. "What d'you say we call again-all together? There don't seem to be any path leading anywhere."

They formed their hands into megaphones, calling loud and long, but there was no answer save a long drawn out echo.

"Again," said Tom, "and louder."

Once more their voices rose in such stentorian chorus that it left them breathless and Connie's head was throbbing as from a blow.

"Hark!" said Doc. "Shhh."

From somewhere far off came a sound, thin and spent with the distance, which died away and seemed to mingle with the voice of the breeze; then absolute silence.

"Did you hear that?"

"Nothing but a tree-toad," said Garry.

They waited a minute to give the answering call a rest, if indeed it came from human lips, then raised their voices once again in a long _h.e.l.loo_.

"Hear it?" whispered Connie. "It's over there to the east. That's no tree-toad."

Whatever the sound was, the distance was far too great for the sense of any call to be understood. The voice was impersonal, vague, having scarce more substance than a dream, but it thrilled the four boys and made them feel as if the living spirit of that footprint at their feet was calling to them out of the darkness.

"Even still I think it must be near the stream though it sounds way off there," Tom pointed; "we might head straight for the sound or we might follow the stream up. It may go in that direction up a ways."

They decided to trust to the brook's guidance and to the probability of its verging in the direction of the sound. It wound its way through intertwined and over-arching thickets where they were forced to use their belt-axes to chop their way through. Now and again they called as they made their difficult way, challenged almost at every step by obstructions. But they heard no answering voice.

After a while the path became less difficult; the very stream seemed to breathe easier as it flowed through a comparatively open stretch, and the four boys, torn and panting, plodded along, grateful for the relief.

"What's that?" said Garry. "Look, do you see a streak of white way ahead-just between those trees?"

"Yes," panted Connie. "It's a tent, I guess-thank goodness."

"Let's call again," said Tom.

There was no answer and they plodded on, stooping under low-hanging or broken branches, stepping cautiously over wet stones and picking their way over great ma.s.ses of jagged rock. Never before had they beheld a scene of such wild confusion and desolation.

"Wait a minute," said Tom, turning back where he stood upon a great rock and holding his lantern above a crevice. "I thought I saw something white down there."

They gathered about him and looked down into a fissure at a sight which unnerved them all, scouts though they were. For there, wedged between the two converging walls of rock and plainly visible in the moonlight was a skeleton, the few brown stringing remnants depending from it unrecognizable as clothing.

Tom reached down and touched it with his belt-axe, and it collapsed and fell rattling into the bed of the cleft. He held his lantern low for a moment and gazed down into the crevice.

"This is some spooky place, believe _me_," shivered Connie. "Who do you suppose it was?"

A little farther on they came upon something which apparently explained the presence of the skeleton. As they neared the spot where they had seen what they thought to be a tent among the trees, they stopped aghast at seeing among the branches of several elms that most pathetic and complete of all wrecks, the tattered, twisted remnants of a great aeroplane. A few silken shreds were blowing about the broken frame and beating against the network of disordered wires and splintered wood.

CHAPTER VI THE MOUNTAIN SHELTER

For a few moments they stared at the wreck and said nothing.

"Maybe it was Kinney," suggested Doc, at last. "Do you remember about Kinney?"

"Come on," urged Tom.

Half reluctantly the others followed him, glancing back now and again till the tattered ma.s.s became a shadowy speck and faded away in the darkness.

"He started from somewhere above Albany," said Doc, "and he was never heard of again. I often heard my father speak about it and I read about it in that aviation book that Roy loaned me."

"He's going to loan it to me when he gets it back from you," said Connie; "he says you're a good bookkeeper."

"Put away your little hammer," laughed Garry.

"Some people in Poughkeepsie thought they heard the humming of the engine at night," said Doc, "and that's what made people think he had got past that point-but that's all they ever knew. Some thought he must have gone down in the river."

"How long ago was it?" Garry asked.

Tom plodded on silently. It was well known of Tom that he could not think of two things at once.

"Five or six years, I think," said Doc.

"That would be too long a time for the wreck, seeing the condition it's in," said Garry, "but anything less than that would be too short a time for the skeleton."

"Do you mean they were lost here at different times?" Connie asked.