might have known it," said Dick, in disgust. "He always takes the oars up to the barn with him."

The barn was a good distance off and none of the boys relished running that far for oars. More than this, they felt that by the time the oars were brought the other craft would be out of sight and hearing, and thus the trail of the midnight prowlers would be lost.

"Here is a bit of board," said Sam, searching around. "Let us use that for a paddle. The current will carry us almost as swiftly as if we were rowing. The main thing will be to keep out of the way of the rocks."

"I wish those chaps would run on the rocks and smash their boat to bits," grumbled Tom, who had gotten a stone in his loose shoe and was consequently limping.

The boys shoved the rowboat from the creek to the river and leaped in. Dick, being the largest and strongest, took the board and using it as a sweep, sent the craft well out where the current could catch it. Down the stream went the boat, with Sam in the middle and Tom in the stern. There was no rudder, so they had to depend entirely upon Dick, who stood up near the bow, peering ahead for rocks, of which the river boasted a great number.

"Those fellows must know this river," remarked Sam, as he started to lace his shoes, there being nothing else just then to do.

"They ought to—if they are the fellows who visited our henhouse before," answered Tom. "Dick, can you see them?"

"No, but I know they must be ahead."

"Perhaps they went ashore—just to fool us."

"They couldn't get ashore here very well—it is too rocky, you know that as well as I do. Listen!"

They listened, but the only sound that broke the stillness was the distant roar of Humpback Falls, where Sam had once had such a thrilling adventure, as related in "The Rover Boys at School." Even now, so long afterward, it made the youngest Rover shiver to think of that happening.

A minute later the boat came clear of the tree shadows and the boys saw a long stretch ahead of them, shimmering like silver in the moonbeams. Sam, looking in the direction of the opposite shore, made out a rowboat moving thither.

"There they are!" he cried.

At once Dick essayed to turn their own craft in that direction. But with only a bit of a board for a paddle, and with the current tearing along wildly, this was not easy. The rowboat was turned partly, but then scraped some rocks, and they were in dire peril of upsetting.

"I see where they are going!" cried Tom. "To the old Henderson mill."

"We'll have to land below that point," said his oldest brother. "If I try to get in there with only this board I'll hit the rocks sure."

"They are taking chances, even with oars," was Sam's comment. "See, they have struck some rocks!"

He was right, and the Rovers saw the boat ahead spin around and the two men leap to their feet in alarm. But then the craft steadied itself, and a moment later shot into the shadows of the trees beside the old flour mill.

It was not until five minutes later that Dick was able to guide their own rowboat to the shore upon which the mill was located. They hit several rocks, but at last came in where there was a sandy stretch. All leaped out, and the craft was hauled up to a point out of the current's reach.

"Now to get back to the mill as soon as possible, and corner those fellows if we can," said Tom, and without delay the three Rover boys started through the woods in the direction of the spot where the two men had landed.

CHAPTER V

AT THE OLD MILL

The Henderson mill was now largely so only in name. So far back as the Rover boys could remember, it had been a tenantless structure going slowly to decay. The water wheel was gone, and so were the grinding stones, and the roof and sides were full of holes. Henderson, the owner, had years ago fallen heir to a fortune, and had moved away, leaving the building at the mercy of the tramps who frequently stopped there.

It was no easy matter to climb around or over the rocks which lay between the boys and the old mill, and the darkness under the thick trees was intense. They felt their way along slowly, and Tom was careful to carry the shotgun with the barrel pointed downward, that there might be no accident.

"More than likely those fellows have been putting up at the old mill," said Dick.

"They'll leave now—if they think we are coming," answered Sam.

"Let us keep quiet," put in Tom. "If they hear us talking they will surely skip out."

After that but little was said. Foot by foot they drew closer to the dilapidated structure, until it loomed up dimly before them. Then Dick motioned for the others to halt.

With bated breath the boys listened. At first they heard little but the rushing of the water over the rocks. Then came a sudden cracking of a rotten floor board, followed by an exclamation.

"Confound the luck! I've put my foot through the floor again," growled a man's voice. "Shelley, why don't you light the lantern? Do you want me to break my neck?"

"If I light the lantern the Rovers may come here," was the answer from the man called Shelley.

"Oh, they went down the river—I saw them."

"They may have turned in nearby."

Some more words followed, but spoken so low that the boys could not understand them. They heard a faint creaking of the flooring of the old mill, but that was all.

"They are there, that's certain," whispered Dick. "But I don't see how we are going to capture them in this darkness."

"I wish we had a lantern," said the youngest Rover.

"We wouldn't dare to light it, Sam," answered Tom. "Let us crawl up close to the building. Maybe we can find out something more about the men. They may be some good-for-nothing fellows from the village."

As there seemed nothing else to do, this advice was followed, and soon the boys were at one of the broken-out windows of the mill. They listened and looked inside, but saw and heard nothing.

"They are not here," whispered Sam, disappointedly.

"They are not far off," answered his big brother confidently.

"Look!" came from Tom. "A light!"

He pointed through the window to the flooring inside. From between the loose boards shone several streaks of light. As the boys gazed the light vanished and all was as dark as before.

"They are in the lower room, the one where the water-wheel used to be," whispered Tom. "Maybe that is where they have been hanging out."

"Come after me—but don't make any noise," said Dick, cautiously. "If they have gone into the second room down there maybe we can make them prisoners!"

"That's the idea!" cried Sam. "Just the thing!"

"Hush, Sam, or you'll spoil all."

Scarcely daring to breathe, now that they knew the strange men were so close, the three Rover boys walked to the open doorway of the old mill and went inside. Dick led the way and crossed to where an enclosed stairs ran to the floor below. On tiptoes he went down, not trusting a step until he was sure of his footing. It was well he did this, for two of the steps were entirely rotted away, and he had to warn his brothers, otherwise one or another might have had a fall.

Standing in the wheel room of the old mill the boys saw another streak of light, coming from the room which Dick had suggested. The door to this was closed, a bolt on the inner side holding it in place. There was another bolt on the outside, which Dick remembered having seen on a previous visit.

"We can lock them in if we wish," he whispered.

"Do it," answered his brothers promptly.

The bolt was large and old-fashioned, and Dick had considerable trouble in moving it into its socket. It made a rasping sound, but this was not noticed by the two men, who were conversing earnestly.

"Well, we made a mess of it," growled the man called Shelley.

"So we did. But I didn't think that hired man would wake up. Neither of us made a bit of noise. He