The others waited breathlessly for the boy's return. When he came back he said:

"They've been on board and ransacked the cabin. They found no one there! Now, what do you think has become of Clay?" he added.

"It's a wonder they didn't run off with the boat," Case said.

"Oh, they wouldn't do that," Alex. ventured. "They want to get us. I half believe the men are officers. What gets me is what they built that fire for?"

"Probably thought we were fools enough to run up to it," hazarded Jule.

"But where is Clay?" demanded Case. "We've got to find him. Do you know if they left any one on board the boat?"

"I didn't hear anything said about that," was the reply, "but it is a cinch that they did. And I believe there's more than one on board, too."

"Hard luck to lose the boat after getting so far on our journey!" Jule commented.

"We don't lose the boat, if they are officers," Alex. hastened to say.

"What they want is the crew! We'll fool 'em at that. I'm going to swim over and see what's doing on board. If everything is all right, I'll make a noise like an owl."

"That's a nice long swim," Case objected. "I don't think you can make it."

"Mose made it, didn't you, c.o.o.n?" Alex. replied. "I'm the boy that poured the water into the Mississippi! Nice adventure this?" he continued. "I'm going to give the residents of the valley a chromo each for the manner in which we have been entertained by them! Here goes for the _Rambler_!"

"You act like you meant to walk back to Chicago," Case suggested, as Alex. started away, turning away from the river in order to avoid the people at the fire.

"Oh, I'm only going to walk up a little way and drift as I swim down."

"Come up on the other side, then," Case cautioned. "Then you won't be seen."

When Alex. started away on his perilous trip Mose disappeared, and Captain Joe was nowhere to be seen the next minute. Case searched and grumbled, but did not find them.

"They've gone with Alex.," he suggested. "They always do. Well, let them go, they can swim better than I can! Wish I was along, also."

"If they are officers, the men at the fire," Jule asked, "why don't we go right up to them and find out what's doing? They won't lock us up, will they?"

"That is just about what they will do if they get us," was the slow reply. "We would get out of jail in time, but who wants to lie in a cell when there is so much fun to be had on the river? These fellows have been wired to head us off, probably by the sheriff we met up there. It may be that the diamonds Clay put in the deposit box have been identified as the ones stolen from Rock Island. I wish Chet would show up right now!"

"Oh, well, if they want to coop us up," Jule agreed, "we'd better cut our luck until they find out who stole the diamonds--or, at any rate, find out that we didn't."

The boy ceased speaking suddenly, for the motor boat was getting under way, heading down toward the business wharves!

CHAPTER XXV

COMMONPLACE, AFTER ALL

"Can that be Alex. moving the _Rambler_?" asked Case, as the motors sputtered out their insistent clamor. "I don't believe he has had time to get on board yet."

"Well, Captain Joe has, anyway!" Jule declared, as a sharp bark came from the craft, which now seemed to be turning around. "That's the Captain's voice, all right."

Standing high on the levee, with the lights of the city growing below them, the lads watched the _Rambler_ for a moment and then started on a run up the stream toward a small landing that was not far from the camp-fire.

"If Alex. wasn't on board," Case reasoned, "Captain Joe wouldn't be there. If Alex. is running the boat up to that landing, it is safe for us to go there."

The _Rambler_ did tie up at the landing, and then the boys saw that the rowboat they had missed was tied to her stern. The willow mattresses were also still hanging on to the cords to which they had been tied. The men at the fire started up toward the landing as the boys reached it, but, much to the surprise of the lads, they did not attempt to go on board. In a moment Clay, Alex. and Mose showed their faces on deck.

"Come aboard!" shouted Alex. "I've arranged a surprise party for you here."

"What is Chet doing on there?" demanded Case. "I thought we left him with his new friends, the thieves, in that old house in the city."

"This is no time for story-telling!" said another voice on board, and the man who had been known as Red, the Robber, came out of the cabin and sat down, calmly, on the gunwale. The boys on sh.o.r.e were, by this time, prepared for almost anything. When they reached the deck, Red waved a farewell to the men on the levee and the boat whirled down toward the Gulf of Mexico.

"You see," Alex. grinned, "we don't know where we are going, but we are on our way."

"I know!" Clay insisted, "we are going to complete our trip to the Gulf of Mexico. We've had all the mystery we need on this voyage, and the next one that starts anything in that line will be banished to one of the mattresses!"

"All right," Alex. retorted. "We don't care about knowing what this all means! I reckon it is too commonplace to refer to again."

He grinned at Red and Chet as he spoke, and they both laughed back at him.

"We have with us to-night," Alex. went on, in a very good imitation of the after-dinner orator, "Red, the Robber! His specialty is taking boats away from boys and sneaking off down the river with them--until some one gets the drop on him!

"We also have with us," he continued, "Chester Vinton, the waif who was rescued from a barren island in the Mississippi with a hundred thousand dollars' worth of diamonds in his possession! He will soon do his stunt of telling how he found them in a piece of pie at a Rock Island restaurant.

"This wonderful Chet is also the last word in friendship. When he sees boys who have befriended him, it is his habit to turn them over to thieves, who lock them up--not in anger, but to protect them from other naughty boys!"

Instead of showing anger at this blunt talk, Red and Chet sat down on the gunwale and laughed until the river echoed back their voices. Clay also seemed much amused.

"What's the answer?" demanded Case, turning to Chet.

"Now you boys just wait a short time," Red observed, "and you'll know all about it. I would tell you right now, only I see how hungry you all are. And, seeing that I have a monster beefsteak in the cabin, with ducks ready to roast, and eggs ready to fry, why, it seems like we ought to eat before we mix with any long yarns!"

So Case and Alex. took to the cabin, and the odors of steak and coffee and roasting duck soon filled the boat. While the good things were cooking the _Rambler_ dropped down to a wharf where a tank wagon of gasoline awaited them, and there, also, loads of provisions of all kinds were put on board.

And the strangest part of it all was that there was nothing to pay!

Red appeared to have temporary charge of the boat, and the bills seemed to have all been paid in advance. They were headed down stream when breakfast was eaten.

"We ought to reach the Gulf in three or four weeks, if we hurry!" Red observed, as he carved the ducks. "That is, if we hurry in the right way!"

"I thought it would take until spring," Chet broke in. "I hoped so!"

Alex. regarded the two with a whimsical smile on his freckled face.

"How long will it be before you'll both disappear?" he asked.

"Never again!" laughed Chet. "Say, boys, I did make a quick get-away a couple of times? What? I hated to go, but I just had to."