Morning came, but it brought no news of the absent men. There now seemed to be no possible doubt that some accident of a serious nature had overtaken both, and the boys were at their wits' end to know what steps to take.

There had been but one canoe for the outing, so it was not possible to follow up the river course in pursuit of explanation. The only course was to take the journey on foot. That would be a tedious process, seeing that the river twined in some parts like a corkscrew. Two or three miles might be walked, and yet only half the distance might be covered as the crow flies. However, there seemed nothing else to be done. It was impossible to remain idly at the camp waiting for what might turn up. Meantime, their services might be urgently needed, and delay might only increase the necessity.

"I vote we pack up our outfit in the tents and set off on the chance of finding their tracks," said Bob. "We can take a good supply of cartridges with us, in case we are delayed and need to forage for food."

"It's my opinion that we may have to go a good long way," was Holden's view. "It would be as well to take a small axe and one or two things for possible camping. A pannikin would be useful——"

"And a small coil of rope. You can never go far in the bush without finding a use for rope."

"But suppose they come back in our absence?"

"Ah, that's well thought of," Arnold agreed. "It might mean starting out to hunt for us. We'll leave a note explaining things."

As soon as breakfast was over, the boys made their preparations for departure. They filled knapsacks with such supplies as they deemed necessary to meet the circumstances and possible emergencies. They packed away the loose articles of the camp outfit, and pinned a note against the flap of the tent to explain the cause of their absence to any person who might reach the ground before their return. Then they set out bravely on their quest.

It was their first intention to follow the course of the river, even though their journey might be considerably lengthened thereby. But very soon it was found that such tactics were, in the main, impracticable. In some parts the banks were steep and rocky; in others they were so thickly clothed with bush that a pathway was only possible after the axe had cut its way. The latter was particularly the case when a certain great bend of the Athabasca was reached, so the chums determined to attempt a short cut across the loop by plunging straight through the forest.

"It seems easy enough," Alf had said. "We are going about due north, I think. The bend goes due west, but as the main part of the river flows north according to the map, if we go straight on we are bound to strike the water again."

"Right, old man," responded Bob. "In any case, the paters could not be so near home, or they would have had plenty of time to get back, even by crawling. So it would be almost wasting energy to trudge so far out of the way."

It is one thing to say "go north," it is quite another matter to hold a steady course in a forest. The Indian can do it; likewise the trapper. They know the signs of the compass such as Nature has provided for them. They know on which side of the trees certain moss is to be found, and they know the signs that the blizzard wind leaves behind it when it has passed on its way from arctic zones. To such as have been initiated into the higher mysteries of woodcraft from their earliest years, a due course to any set point of the compass is second nature. But those who are unlearned in the art soon find out their mistake when they put their inexperience into practice. The sun is a pointing finger to the craftsman—a disastrous lure to the ignorant.

Bob and Alf pursued their way pluckily. Determined to keep a steady course, the tomahawk had to be requisitioned at frequent intervals in order to clear a passage through the thorns and binding creepers that impeded the way.

At any other time the adventure would have been one of sheer delight, for who would not have enjoyed exploring unknown land—probably land, too, where only the Indian's foot and the feet of the wild creatures of the forest had ever pressed?

Once or twice the boys saw the great velvet eyes of an antelope peeping at them through a screen of maple leaves. Again the scrub would rustle, as a fox crouched down to hide his skulking body from the strangers' sight. The cat-birds were calling their sad messages to each other among the maple leaves, and lively little chipmunks would utter their shrill piping sounds of warning to their friends as they started before the advance of the young explorers. Yes, it was an experience to fill the heart with joy when any ordinary call inspired the venture spirit.

On this occasion, however, neither of the boys had eyes for such pleasant sights, or ears for such sounds as are the delight of the trapper's life. Their minds were too full of anxiety to permit room for ordinary enjoyment, and they hardly spoke as they pressed forward in single file.

In this way they continued for two hours or more. At intervals they would take it in turn to act as leader and handle the axe; but they did not allow a pause in the pushing forward, until at last Bob called a halt, feeling that a rest had been earned.

"We ought to be getting near the river again by this time," he remarked.

"That's what I've been thinking," said Alf. "You see, it was such a sharp westward turn that the river took after we crossed the ford, that I don't think we can be far off now. It must come round to the east again."

"Yet there's no sound of it——"

"That is what's puzzling me. We've covered a couple of miles at the least."

"And done enough work for four," added Bob. "However, let's get to work again. The sooner there, the sooner this job will be over."

"Thank goodness it looks pretty clear ahead now—more pine trees and less of the beastly scrub," said Holden.

Once more the boys pressed forward; but, although they continued the march for quite another hour, apparently they were as far off as ever from the river, for they neither sighted water nor came within hearing distance of the object of their search.

Again they stopped and faced one another with perplexed expressions.

"I'll tell you what it is, old man—we've missed the way," said Alf.

But Bob was never ready to admit defeat of any sort.

"Nonsense," he said. "We've kept a fairly straight course."

"Or thought we have. To my mind, if we'd kept straight on we ought to have reached the river by this time. As it is, there is no sign of it."

"That's true. Except for being free from the brushwood, we might almost be where we started. It looks much the same—no slope or any other sign to suggest that we are nearer to the water."

"What's to be done?"

"I see nothing for it but to go back again and follow the river, as we were doing in the first place. We were fools to think of taking short cuts. The other way may have seemed longer, but it would have been a deal shorter in the long-run."

Both the boys were feeling rather fagged by this time, for their trudge had been of an exceptionally fatiguing nature. But each kept the thought to himself, and cheerfully stepped out with the intention of retracing his steps. It was a disappointment and irksome enough; yet there was no help for it, and the situation had to be faced pluckily.

But all the best intentions seemed to go wrong that day, and it did not take an hour's marching before Bob stopped and turned to his chum with a crestfallen countenance.

"Look here, old man, I don't know what you're thinking, but my own opinion is——"

"That we've missed the path; that we are lost——"

"I'm afraid that is the truth of it. You see, we've never come to any of the places that we had to clear with the tomahawk."

"Then what's to be done?" Alf questioned.

Arnold took out his watch and looked at it.

"What's to be done? Grub. That's the first thing. After that we can make fresh plans. It's noon now, and we can do nothing while we're hungry. Besides—well, to tell the truth, I'm feeling a little tired."

"I, too," responded Alf, with a faint smile. "I didn't want to say so while I thought you wished to go on——"

"Just my own idea," Bob returned, with a slight laugh, as he lowered himself to a soft place under the shadow of a large maple. "So we'll rest here and have a bite. We'll feel better afterwards."

The little camp was made, and a meal was enjoyed from the contents of Bob's haversack—biscuits and cold venison. Neither of the lads thought it was worth while to trouble about shooting and cooking a meal just then. They would reserve that till night, in the event of their not being able to find Crane Creek again.

After a considerable rest, the march was resumed for the third time. On this occasion, however, the process was varied. Their first purpose was, of course, to find the path by which they had come; so at Bob's suggestion they carefully proceeded to walk in a circle—checking the route by notching the trees, and taking wider courses each time a circuit was completed.

But even these means were ineffective. Circle after circle was made, and still the earlier track was undiscovered. All the afternoon was thus occupied, and, when evening came, the boys were footsore and weary—glad to throw themselves down on the first piece of springy grass, too tired even to trouble about preparing food.

The disappointment was beyond words. They had started out in the morning full of cheerful hopes of being able to render aid to their parents who (they felt sure) were in need of assistance. And now, not only was this purpose frustrated, but they themselves were in that terrible plight of being lost in the backwoods—a hundred miles or more from the haunts of white men, with nothing but plucky hearts to help them, and limited ammunition to supply bodily needs.

The sun passed over their heads and sunk somewhere beyond the forest. They could not tell where it vanished, for the camp was amid such dense surroundings that they could hardly see beyond a hundred yards through the branches.

With dusk, and after a sparse meal, it was decided to light a fire, more for the sake of the cheering sight than the need for warmth.

Bob was the first to rise, and as he stood upright he was heard to give vent to a decided—

"Bother it!"

"What's the matter?" grunted Alf, as he also proceeded to rise.

"Matter?" repeated his chum. "Nothing; only I have stuck my head into a cloud of moths—big ones and little ones. There seems to be a regular party going on under this tree."

"It's that luminous patch in the tree that we've been sitting under," said Holden, at the same time drawing his friend's attention to what looked like a patch of light on the trunk of the maple about five feet from the ground.

"That's curious," remarked Bob, bending forward to examine the spot. "I wonder what it can be? It looks like the light on one of those luminous match-boxes that are made so that you can see them in the dark."

"They say that rotten wood sometimes has that effect——"

"But this tree is quite sound. And see! There's another the same on that tree to the right!"

It was certainly strange, and the boys picked up their guns and sauntered over to examine the next trunk, on which they found the same peculiar light attracting an equally numerous lot of moths of many descriptions.

"There's another!" exclaimed Alf, pointing ahead of him.

"And another!"

"And another!"

By this time the boys were quite excited by their discovery, and when Alf suddenly drew attention to the further discovery that the marked trees were almost in a straight line, their excitement was still further stirred.

"It's the strangest thing I ever heard of—in the natural history way," the younger lad said. "To find all these trees marked on the same side, and all in a straight line—why, it would puzzle the brains of anybody to explain it!"

Without any decided plan, and more out of curiosity than from any other motive, the chums proceeded from one tree to another, examining each as they reached it, and marvelling all the time at what they decided as being one of the most remarkable freaks of Nature that they had ever heard about.

Then they became aware of a strange sound that reached them from no great distance through the trees. It was a most remarkable sound—not that of any animal with which they were familiar; indeed, it was not a sound that suggested any beast or bird.

"What on earth is it?" questioned Alf, as the weird wail sighed through the forest.

"It sounds like a harmonium in distress!" replied Bob, with a slight laugh. And even as he spoke the wail was repeated, though this time could be distinctly heard the voice of some person struggling to articulate to some musical accompaniment the words—