Very early the next morning the ranger was afoot. Before ever the faintest streaks of light penetrated the thicket, he had started the coffee to boiling on the little stove, and breakfast was almost ready before he wakened his young comrades.

“Why didn’t you call us sooner?” asked Charley indignantly, as he leaped out of his blanket. “It’s our place to do the work here, not yours.”

The ranger smiled. “It would have been cruel to waken you earlier. It’s easy to see that you aren’t accustomed to such stiff work as your hike here yesterday must have been. You slept like logs.”

“We intend to do our full share of the work,” said Charley.

“I’m sure of it,” replied the ranger. “If I had thought you were trying to shirk, I’d have had you out of bed long ago.”

Many a time afterward Charley thought of that statement and pondered over it. He was learning a good deal about life these days.

Grateful indeed was the warm coffee, for the April morn was chill. Quickly the food was eaten, and the ranger prepared to depart.

“I don’t want to burden you with rules,” he said in parting. “Your business is to protect the forest. Every day you will meet some new situation. You must do your best to protect the harmless creatures of the forest, as well as the timber. That means you may have to deal with gunners who are violating the law. Such men, with firearms in their hands, are dangerous. You may come across timber thieves. Get acquainted with your territory so that you can tell whether a felled tree is on state land or on private property. Your maps show you where the lines run, and you will find the trees along these lines blazed. If you find lumbering operations going on within the state forest, do your best to stop the cutting and report the matter at once. You may find traps set out of season. And it is practically certain you will have to deal with fires and perhaps the men who start them. Being a fire patrol involves a whole lot more than merely walking about through the woods. I can’t give you rules that will cover all the situations you will find yourself in. Common sense is the best rule. The chief has given you a very important post here. It’s an unusual responsibility for one so young. But we both expect you to make good. I’ll be disappointed if you don’t. You know if you fail, I’ll have to take part of the blame.” He shook hands with both boys and was gone.

“He’s a prince,” said Charley, after the ranger had left the thicket. “He knows just how to treat a fellow. Why, I’ve simply got to make good now. I’d get my ranger in bad if I didn’t.”

Quickly they put their camp to rights, then slipped their pistols into their pockets and got their fishing-rods.

“What is the first thing on the programme?” asked Lew.

“We’ll go up to the top of the hill and have a good look over the country,” replied Charley. “It’s just about time for campers to be cooking their breakfasts. If there are any of them near us, we might see the smoke from their fires and locate them. You know the ranger wants us to keep tab on everything that’s going on in our district.”

They ascended the mountain and climbed the tree from which they had viewed the country on the preceding day. The sun was just coming over the eastern summits, sending long, level rays of light flashing among the dark pines, making beautiful patterns of sun and shade. In the bottoms the night mist had gathered in little pools, in places completely blotting out the landscape. The tree tops, upthrusting through these banks of fog, looked like wooded islets in tiny gray lakes. In every direction the two boys scanned the country, looking sharply for slender spirals of smoke. But they saw only mist curling upward.

“It looks to me,” said Lew, “as though mighty few people ever get into this valley. It’s such a hard journey to get here that I suppose the fishermen will stop at the streams in the valleys nearer the highway, and nobody else would want to come here at this time of year. Unless this timber is set afire purposely, I believe there is not much danger of its being burned.”

“There’s just the rub,” replied Charley. “It would naturally be safe, being so hard to get to, and for that reason it wouldn’t be watched as well as more accessible regions, particularly when it is difficult to get fire patrols. But because some one is evidently trying to burn this particular stand of timber, it is especially necessary to guard it. Mr. Marlin wants it watched continually, but so secretly that no one will realize that it is being guarded. That might make the incendiary careless providing he comes again and so lead to his detection. We must do nothing to betray ourselves. We’ll have to be careful not to mark this tree in any way, so that a passer-by would guess it was used as a watch-tower. And we shall have to be sure that we don’t wear a path leading from it to our camp.”

For many minutes the boys sat in the tree, well screened from observation by the spreading limbs, yet themselves able to see perfectly. In every direction they searched again and again for telltale columns of smoke, but saw nothing.

“It looks to me,” remarked Charley, “as though there isn’t a soul in this region except ourselves. If that is so, it is the best possible time to do a little exploring. Suppose we take a look at the valley above our camp. We can cover a lot of ground between now and noon and yet get back here for another observation during the dinner hour. We ought to be in this watch-tower or at some other point equally good every time men would naturally be having fires, and that means morning, noon, and night. Between times we can explore the forest. It means some pretty stiff hiking, but I guess we can stand it.”

They drew their map and compared it with the country as it actually appeared.

“We aren’t so far from the end of the state land in this direction,” commented Lew. “That’s the very place you suggested exploring. We might look up the line, as Mr. Morton suggested. You notice the stand of pines ends a long distance this side of the line. That’s all hardwood forest up that way.”

“The sooner we get at it, the better,” agreed Charley.

Carefully they descended the tree, picked up their fishing-rods, and hastened down the mountainside as fast as it was safe to travel. The nearer they came to the centre of the valley, the larger the trees grew. Evidently the rich soil had worked down into the bottom, during the centuries, and the tree growth was enormous. Under these huge trees there was no underbrush, and the two boys could make fast time. They approached the stream, which flowed swiftly along under the tall pines, where they had no doubt trout innumerable lurked in the shadowy depths. The temptation to stop and fish was strong, but they put it aside and pushed on up the valley.

For a long time they passed like ghosts among the pines. The earth was springy with the accumulated needles of many years, into which their feet sank silently. Under the huge trees everything seemed to be hushed. There was no wind to set the pines awhispering, and the music of the brook stole through the forest like the low singing of a muted violin string.

For a long distance they passed through a pure stand of pines. Then the character of the forest began to change. Soon they were in a mixed growth, and not long afterward they found practically nothing but deciduous trees about them.

“We’re not far from the line now,” suggested Lew. “This must be the stand of hardwoods we saw from the lookout tree. I doubt if it is more than half a mile to the line.”

“Keep your eyes open for blazed trees,” said Charley. “We ought to see some before many minutes.”

They had gone on, perhaps a quarter of a mile, when Lew said, “It looks pretty thin ahead. Either there is a natural opening in the forest or else the timber has been cut out.”

Charley thought of what Mr. Morton had told him about timber thieves operating along the boundary lines. He was glad that he had decided to explore this particular section of his district. A moment later he was still more glad, for the stillness of the morning air was suddenly broken by a splitting, rending sound, which was followed by the crash of a great tree as it came thundering to earth. There could be no mistaking the sound. A tree had been felled. Both boys stopped dead in their tracks and looked questioningly at each other.

“Timber thieves!” said Charley in a low voice. His cheeks paled a trifle. Then a look of determination came into his eyes.

“What shall we do?” asked Lew in a loud whisper.

“I don’t know,” replied Charley. “But we’ll find out what they are doing. Then we can decide what to do ourselves.”

He drew his automatic but as quickly thrust it into his coat pocket, as he remembered what the ranger had told him. But though the pistol was in his pocket, he still grasped it in his hand. The tense look on his face showed plainly enough that he was ready to shoot right through his coat. Lew, observing his companion’s movements, followed his example.

Minute after minute the two young forest guards stood silent, listening for the sound of axes or other customary noises that ordinarily accompany lumbering operations. But the morning stillness was undisturbed. A puzzled expression crept over their faces.

“Maybe that tree wasn’t cut at all,” whispered Lew. “Maybe it just fell of itself.”

“We’ll find out,” replied Charley, and cautiously they began to make their way toward the point whence the sound had come. Sheltering themselves behind trees, they advanced rod after rod. The stillness remained unbroken. The stand of trees grew thinner, with more and more underbrush. Presently they saw before them an unmistakable clearing in the forest. Rapidly they advanced, screened by the bushes, until they stood close to the edge of the clearing. Beyond question somebody had been cutting trees. Over a considerable area the timber had been felled, and whoever had felled it had cut ruthlessly. Hardly a sapling remained in all the cleared area. On every hand trees lay prone. Some had been trimmed and cut into pieces. Some remained exactly as they fell. Everywhere freshly cut stumps told plainly enough what had occurred.

“Somebody’s cutting timber all right enough,” whispered Charley, “and it’s on state land. I wonder where they are. They certainly cut that tree we heard fall, but I haven’t heard an axe or a human voice and I don’t see any signs of lumbermen.”

“Maybe they’re at camp eating breakfast. It’s still early, you know.”

“If they are,” said Charley, “then this is the very time to investigate. We’ll look around before anybody gets back.”

Glancing once more about the opening to make sure that nobody was in sight, they stepped from behind their concealing bushes and started across the open space. But immediately they came to a dead stop. Like rifle-shots, a succession of sharp sounds rang out, accompanied by splashing noises. The two boys were at first alarmed, then puzzled. They looked at each other in amazement.

“What was that?” asked Lew.

“I don’t know,” replied Charley. “At first I thought somebody was shooting at us. But I didn’t hear any bullets hum. And the noise didn’t sound exactly like a gun, either. It was like the noise a fellow makes when he hits the water real hard with a board.”

In every direction they scanned the clearing. They saw no living things but the trees. “It’s queer,” commented Charley. “Let’s look at that nearest tree that’s down. Maybe we can learn something from it.”

They walked over to the tree, then studied it in amazement. “I never saw anything like that before,” cried Lew. “I don’t believe that was ever cut with an axe. It looks as though it had been gnawed off.”

“It has,” cried Charley with sudden excitement. “I understand the whole thing now. We’ve found a colony of beavers. I never saw a live beaver, but I’ve read about them and seen pictures of their huts and their work, and that looks exactly like the pictures. And those noises like rifle-shots were their alarm signals. They slap the water with their tails when they are frightened and dive under water. I suppose they’re all in their lodges now, and we’ll never get a peep at them. Gee whiz! Just think of finding beavers, Lew, real beavers. I didn’t know there were any in Pennsylvania.”

“It seems to me that I read something about the game commission stocking the state with them a few years ago. I think they put a number of them in the state forests. Doubtless they have multiplied in numbers and started new colonies.”

“That explains it,” said Charley. “Gee! I’m glad we found these fellows. And I’m just as glad that they aren’t timber thieves. You know, Lew, it made me feel kind of queer to think of facing real timber thieves. I didn’t like the idea a bit. But I kept thinking about Mr. Morton and what he said about his being blamed if I fell down, and I made up my mind I’d do it, no matter what happened.”

They now turned their attention to the felled tree once more, studying the innumerable teeth marks, like so many tiny chisel cuts, on stump and butt. Then they noticed the great chips lying about the stump, some of them half as big as dinner plates.

“It gets me to understand how they can bite out such huge chunks,” said Lew, “when their teeth are evidently so small. Why, you’d think an animal would have to have a mouth as big as a hippopotamus to take bites like these.”

Charley laughed. “Looks that way, doesn’t it?” he said. “But as I remember it, what I read said that the beaver gnaws out parallel rings around the trunk and wrenches out the wood between. It’s like sawing two cuts in a board and chiseling out the board between them.”

“I see,” said Lew. “But I should think they’d break their teeth all to pieces.”

“So should I. But they have very strong teeth that grow out as fast as they wear away, and that are as sharp as a chisel. I wouldn’t want a beaver to bite me. I’ll bet he could bite right through a bone.”

“I suppose,” said Lew, “they cut these trees to use in making their dam; but what gets me is how they are going to get the trees over to the dam. It would take a team of horses to drag this trunk. It’s fifteen inches in diameter.”

“The article I read,” said Charley, “stated that as the beaver dams became higher, the land adjacent was flooded and that the beavers made little canals through the flooded area and floated their logs where they wanted them. You notice that they have gnawed the limbs off of a number of these trees and cut several of the trunks into lengths. I was sure they were sawlogs when I first saw them.”

“Well, there isn’t enough water here to float a log,” said Lew, “though it’s mighty wet and it looks as though the water was several inches deep a little farther on. Let’s see if we can find a canal.”

They stripped off their shoes and stockings, and, rolling up their trousers, began to wade. Very soon they found the water nearly knee-deep.

“There’s more water here than there seems to be,” admitted Lew. “There’s so much marsh-grass and so many water-plants it fooled me.”

Cautiously they waded about. Suddenly Lew plunged forward, and only by grasping a bush did he save himself from getting completely wet. As it was, he found himself standing upright in three feet of water. After he recovered from his surprise, he felt about with his feet.

“This is their canal all right enough,” he said. “It’s very narrow, but it will float anything that grows in this forest.”

He scrambled out and the two boys made their way back to dry ground. “How are you going to get dry?” asked Charley. “I don’t want to make a fire unless it is absolutely necessary.”

“Never mind about me. I’ll dry off soon enough. Let’s find their dam.”

They made their way toward the run and soon discovered the dam. It was a great pile of branches, stones, moss, grass, mud, bark, etc., that had been built across the stream and extended for rods on either side. It looked very solid, yet the water did not pour over it, but filtered through it.

“Think of all the work it took to make that,” cried Lew. “Why, every stick in it had to be gnawed down and floated here, and all the bark and grass and roots had to be pulled and brought here and the stones collected. And say! How in the world do you suppose they ever handled those stones? And how do you suppose they ever anchored the stuff when they began building? I should think the current would have swept everything away at first. That’s a pretty swift stream.”

“I read that they start their dams with saplings, which they anchor across the current with stones. They are much like squirrels, you know, and can use their fore paws about as well as we can use our hands. I suppose the stones lose weight by displacing water, but if I hadn’t seen these rocks, I’d never have believed that such big stones could be handled by animals no larger than beavers.”

“See here,” said Lew. “These willow branches must have taken root, for they seem to be growing right up out of the top of the dam. And there’s a birch that’s surely growing. You know the branches of some trees will root if you put them in water, especially willows. Why, if they continue to grow and take more root, there’ll be a hedge of living trees right across this brook. The dam will become so dense that it will back up a great quantity of water. I reckon this bottom will just naturally turn into a swamp after a time.”

“Now that’s interesting,” suggested Charley. “You know the Bible tells us the world was made in six days; but it seems to me it isn’t finished yet. Every rain washes down soil from the hills and helps to fill up the valleys and the river-bottoms, and the floods scour out the watercourses and carry earth and stones down to the ocean. And here we see a piece of land that used to be fine, dry bottom, now becoming a swamp. It looks to me as though the earth is changing every day.”

They examined the dam more critically. “It’s two hundred feet wide if it’s an inch,” said Lew, “though the brook isn’t more than fifteen or twenty. You see, it extends on each side of the brook to land that is a little higher than the level of the stream bank. That’s what makes this big head of water. At the least there are several acres of it.”

“There’s one thing that we haven’t seen yet,” added Charley, “and that’s their houses. They ought to be some distance above the dam.”

“I wonder if those are beaver lodges,” said Lew, pointing to some bulky heaps of brush at a little distance up-stream.

“That’s exactly what they are. They don’t look much like houses, do they? But I guess they’re pretty snug inside. The entrances are deep under water, you know, so that the ice can’t clog them in winter, and so that the beavers can get to their food all right.”

“What do they eat, Charley? Do you know?”

“Sure. They eat roots, and tender plants, but mostly bark from certain trees. I believe these are willow, poplar, birch, and some others. They cut down the wood in summer and pile it under water in front of their huts and hold it down with stones.”

“Well, what do you think of that!” cried Lew.

“They eat a pile of it, too. I don’t remember how many trees that article said a colony of beavers would eat in a winter, but I’m sure it was up in the hundreds. I remember how astonished I was when I read about it.”

“No wonder they clear the forest so fast. I wonder if we ought to tell Mr. Marlin. Maybe he doesn’t know about these beavers. They might begin to cut down his virgin pines. I’m sure he wouldn’t want that to happen.”

Charley laughed. “I’d bet my last dollar that Mr. Marlin knows all about these beavers. You can bank on it that he knows all there is to know about the territory he has charge of. And as for the beavers eating the pines, it seems to me that I read that they never touch evergreens.”

A ray of sun slipped through the leaves above them and fell directly upon Charley’s face. He glanced up and was surprised to note how high the sun had climbed. Then he looked at his watch.

“Gee whiz!” he cried. “We must have been fooling around this beaver dam for more than an hour. We must be about our business. We’ll go on and locate the boundary line.”

“I wish we could get a glimpse of a beaver,” sighed Lew.

“Not much use to wish it,” said Charley. “They’re furtive, and I suppose they will stay in their lodges for hours. It seems to me I read that they work at their dams mostly at night. We’ll go on now, but maybe we could come up here some moonlight evening and see them at work.”

They made their way around the beaver dam and continued on up the valley. Within a few hundred yards they came upon a blazed tree. Speedily they discovered a second. Then, following the line indicated by these two trees, they rapidly passed tree after tree blazed and painted white, tracing the line entirely across the valley. They picked out some landmarks by which they could readily locate the line again.

“If anybody except those beavers starts any timber cutting,” said Charley, “we’ll know in a second whether he’s cutting the state’s wood or not. Now I guess we’d better hustle back to camp.”

Lew got their noonday meal while Charley ascended once more to the watch tree at the top of the mountain and made a careful survey of the country. Not a sign of smoke could he see in any direction. No fire was discovered during the afternoon hike. The evening inspection from their tower was equally reassuring. After a brief chat by wireless with their friends at Central City, and through them sending their nightly message to the forester, telling him that all was well, the two tired young fire patrols rolled up in their blankets and were quickly asleep, serene in the knowledge that the forest they guarded was safe.