though the moon shone brightly, there were shadows in the forest that surrounded the mysterious camp—mysterious in the sense that the boys did not know whose it was. and these shadows made silent progress difficult. rick and chot were very likely to slip and stumble over a rock or fallen branch, making a noise that would arouse the sleeping men.

several times they did stumble, and thus ruddy had the advantage over them, for his padded paws made no sound. but though the boys made several noises none of them seemed to have any effect. it remained dark and quiet in the camp—dark that is save for a glimmering camp fire and the silvery moon, the light of which was very welcome to the boys.

there was little for the lads to discover in the camp itself. they had learned this much while taking observations from their hiding place just within the tunnel. from their vantage point they had seen the water coming down a rocky defile, though its exact source they could only guess at. they could not tell whether it came through another tunnel—part of the series of mysterious underground channels in that part of the country—or whether it flowed along in the open.

this secret they hoped to solve on their night-scouting expedition, and after they had made a detour of the camp they listened for a sound of rippling or gurgling water which would put them on the right track.

“well, so far so good,” remarked chot when they had gotten safely some distance up the trail, above the log shack and the sleeping men.

“that’s right,” agreed rick. “ruddy, you’re a dandy!” he said to the dog. “you didn’t make a false move.”

“and not as much noise as we did,” added chot as they both petted their canine companion.

“i should say so!” chuckled rick. “that time we both nearly fell—i thought sure they’d hear us.”

“so did i. but i reckon we’re all right now.”

“i guess so.”

they had come out from under a clump of trees and were walking along a rough trail that led up the mountain. the moon shone gloriously making objects very plain to see. there was little wind and soon the boys heard the murmur of water off to their left—a sound for which eagerly they had been listening.

“there’s the river,” exclaimed chot.

“i hear it,” admitted rick. “either the one we’re after or another. let’s head over that way.”

they walked on side by side, with ruddy trailing them. rick had ordered his dog to heel, for he did not want the setter rushing on ahead through the brush, perhaps stirring up a skunk or some small wild animal that might cause the dog to bark, thus betraying their presence.

as they went on, the noise of the water became louder to their ears, until at last they emerged in view of a beautiful stream flowing in the centre of a small valley, bordered on either side by trees and bushes.

though the stream was called lost river, or by various other names in which the word “river” occurred, it must not be supposed that it was a large waterway. in fact it was not more than a good-sized brook, in places, though in others it attained the width of what, in some parts of the country, is called a creek. but lost river it had been christened and so it shall remain, as far as i am concerned.

the boys stood for a moment impressed by the beauty of the scene that they had come upon. under the moon everything was glorified—the rippling, sparkling water, the trees, the bushes and even the rough rocks.

“say, this is slick!” exclaimed chot, paying one of the highest compliments in his rather limited vocabulary.

“nifty!” agreed rick, adding his tribute.

but, boy like, they did not pause long to admire just the mere beauty of the place, romantic as it was. they had come upon sterner business, and rick gave a hint of it when he said:

“chot, i don’t believe this stream has flowed here very long.”

“why not? how can you tell?”

“because it’s too near the trees and bushes. and there aren’t many stones along the banks. when a river has run a long time in a place it washes away the dirt and leaves a lot of rocks, and where it washes away the dirt from tree roots the trees partly die. but this looks like a river that has suddenly been turned loose in the woods.”

“that’s what it does,” assented chot. “do you think the men turned it in here?”

“i guess they did,” agreed rick. “and the thing for us to do is to find out where they turned it, and shift it back again so it will run into uncle tod’s tunnel.”

“do you think we can?” asked chot.

“i hope so,” answered rick. “let’s keep on.”

they walked for a few minutes longer and then suddenly, over their heads in a big tree, there was a rustling in the branches—a rustling not caused by the wind, for there was no hint of a breeze then.

“what’s that?” whispered chot, ready with his gun.

“i don’t know,” answered rick, as he, too, brought his weapon around. uncle tod had given the boys each a light shot gun, and they had learned to pick off small game in the woods, shooting, however, only enough for actual needs.

the lads stared up in the tree. the rustling of the branches continued and ruddy, seeing that some business in which he ought to take an interest was afoot, stood at attention. suddenly the dog growled and immediately there was a hiss above the boys’ heads as if an angry cat were there.

“look!” whispered chot, and rick saw that his chum was pointing to two blazing, greenish, reddish spots of light; the eyes of some animal on which the moon reflected.

chot raised his gun, but rick said:

“don’t shoot!”

“why not?”

“it’s only a small bob cat and he won’t hurt us if we go away. shooting will only wake up those men, and we haven’t found what we want yet.”

“but aren’t bob cats dangerous?”

“not if you leave ’em alone, uncle tod told me. and we’ll leave this one alone.”

ruddy had now seen the lithe form of the lynx stretched out on a tree branch overhead. it was not a large animal—in fact not much larger than some overgrown house cat. of course it was more dangerous if cornered, but, as rick had observed, it would not needlessly attack them if not molested.

ruddy growled as if eager for the fray; but rick knew even a large setter dog is no match for a small bob cat, and he ordered ruddy away. the lynx continued to snarl as it glared at those it evidently regarded as its enemies, and remained in watchful readiness on the branch as chot and rick went on their way.

“i’d like to have taken a pop at him,” said chot regretfully.

“so’d i,” admitted rick. “but shot guns aren’t much good against a lynx—not little shot guns like ours. and, anyhow, we don’t want to stir up those men.”

chot agreed to this, and they kept on up along the river.

“’tisn’t so much a lost river now,” observed chot as the stream murmured beside them.

“no, but it’s lost as far as uncle tod is concerned,” remarked rick. “that is until he can shift it back—if he can.”

the boys made a turn in the trail and suddenly became aware of a slightly different sound made by the water. it was a splashing noise, as though a cascade were not far away.

“what do you imagine that is?” asked chot.

“we’ll soon find out,” said rick for, as they advanced they heard the strange sound more plainly.

and then, as they pushed their way through a fringe of bushes growing close to the edge of the stream the lads made a strange discovery.

they had solved the secret of lost river!