Finally they asked Clay all sorts of questions about their progress down the river, when they left Rock Island, when they touched at St.

Louis, and when they reached Cairo. The boy, though wondering, answered the rather personal questions frankly.

It was almost dark when the visitors left the boat. Their last visit had been made to the cabin, to inspect the electric stove, and they pa.s.sed the boys on the prow as they went ash.o.r.e. For a time after their departure the boys discussed the unusual conduct of the visitors, and then Chet and Clay went in to prepare supper.

Taking advantage of a momentary absence of Chet from the cabin, Clay looked in the hiding-place where he had left the leather bag in which the diamonds had been brought on sh.o.r.e. The bag was gone! Clay hastened out on deck to meet two astonished boys.

"Say," Case said, "what's come over Chet? He came out of the cabin like a shot and jumped off on the pier. Then, without even stopping to look back, he ran down into the city! What have you been doing to him?"

Clay stood for a moment like one incapable of speech, then he dropped into a deck-chair and laughed until the tears ran down his cheeks.

Captain Joe and Teddy joined the others in their criticism of his strange actions.

"You didn't get too many high b.a.l.l.s while in the city, did you?" asked Case.

"You might have kept sober enough to bring Alex. back with you!" Jule put in.

"Ah believe yo' done scare dat lad off de boat!" little Mose suggested.

"Well," Clay explained, presently, "I suppose I ought to treat the matter more seriously, for we may have lost Chet for good, but it is funny for all that."

"Why don't you pa.s.s it around?" demanded Case. "Let us in on the laugh!"

"You all know what I did with the articles we found on Chet," Clay responded. "Well, when I took the valuables out of the leather bag, I put burrs from the repair kit and pieces of broken dishes into the bag and hid it where I thought Chet might find it if he looked long enough."

"I don't see anything funny in that," observed Case, with a frown.

"Just wait! When I looked for the bag, just now, it was gone, and the next thing I hear is that Chet has taken to his heels. You see what has happened!"

"The poor little chap!" exclaimed Case. "I'm sorry for him."

"So am I," Clay agreed, "but he ought to have been honest with us."

"We knew what to expect," Jule suggested. "He said he'd get the gems back if he could, didn't he? Now he thinks he's got them, and is lugging off a lot of truck not worth a cent! I call that a shame!"

Clay looked thoughtful for a second and then burst out:

"But is he? Look here, fellows," he went on, excitedly, "suppose he never took the bag at all! Suppose Chet found it and changed his mind about running off with it! Suppose one of the visitors took it!

Suppose that is what they were here for; suppose Chet missed it as soon as they went away and chased on after them!"

"You said the visitors were bankers!" exploded Jule. "What about that?"

"One of them was, but I don't know anything about the others. Strange they should all be so eager to inspect the _Rambler_! Strange they should get off by themselves and talk in whispers! I reckon we're knee-deep in mystery!"

"Well, where did you leave Alex.?" asked Jule. "He hasn't come back yet!"

"And here's another funny thing," Clay went on, without answering the question, directly. "We saw Red, the Robber, up town, dressed like a gentleman! Alex. followed him out of the place where we saw him, and may have got into trouble!"

"Then the stealing of the bag is Red's work!" decided Case. "No need to guess about that any more! How he got his men in with the banker I don't know, but he did it, and one of them took it, and poor Chet saw that it was gone, and now he is following a bag filled with crockery about the city!"

"Pshaw!" Jule exclaimed. "It is dollars to doughnuts that Chet got the bag himself! He said he'd swipe it if he got a chance. You all know that!"

A figure now came dashing down the pier at break-neck speed and Alex.

leaped on the deck and dropped into a chair, wiping the sweat from his face.

"Did you find who he was?" asked Clay, as the boys all gathered around Alex.

Alex. told the story of the steamer and the wrecked stateroom, and ended with the talk he had had with Red, while the boys looked on in wonder at the odd twist things were getting into. Even Teddy Bear seemed impressed by the mystery, Jule declared!

"And how did you get away from him?" demanded Case. "How did you get back here?"

"I jumped and ran, and he caught me," was the reply. "Then he made me promise not to say a word about his escapade on the _Rambler_ and let me go! Can you beat it?"

"What did he have you locked up for?" asked Clay. "I don't understand that."

"Just because he wanted that promise," Alex. suggested. "Is that the answer?"

"It may be," Clay admitted, "but here's the question: Is he a robber or a detective? Is he on the level, or is he just a clever scoundrel?"

"Perhaps Alex. can judge better of that when he knows what has taken place here," Case suggested, going on with the story of the disappearance of the leather bag.

"Red's gang got it," laughed Alex., without a moment's hesitation, as Case finished the story. "He knew Clay put something in the bank, and asked me what it was. Yes, we know all about it now!"

"I just believe Chet took the bag, thinking the gems were in it,"

insisted Jule.

"We'll never know the truth until we find the lad," Clay said, with a sigh.

"Unless Red, the Robber, shows up again in a confidential mood," Alex.

laughed.

"If the supplies I ordered are all in," Clay went on, "I think we'd better be on our way. There's mystery in the very air here!"

"If we stay here long," Alex. prophesied, "the c.o.o.n I biffed on the shin may show up, lookin' for revenge, or Red may come after pay for the furniture I smashed!"

"What did he say about that furniture?" grinned Jule. "You've got the nerve!"

"He never mentioned it," was the reply. "Say," the lad went on, "I believe that chap is all to the good, after all! He seemed to think the smash act was funny."

During the afternoon Case and Mose had caught a large fish and Chet had succeeded in bringing down a wild duck, so the cooking of supper was an elaborate affair. Then Clay made light biscuits and coffee, and fried potatoes, and the boys were as happy as well-fed boys with no one to "boss," usually are, except that they missed Chet.

After supper they discussed the proposition of waiting there a day in the hope of finding the runaway boy, but it was finally decided that he could find them easier than they could find him, so they started the motors and went on toward the Gulf.

The early part of the night was bright, so the boys ran down about twenty miles, as the river ran, and then tied up below a "tow-head"

which stuck up out of the water below an island of good size. They found it necessary to take this precaution always, for the wash of large steamers pa.s.sing up and down would have rattled things in the _Rambler_, if the motor boat was not capsized.

At midnight the sky became overcast with threatening clouds and the wind blew in fitful gusts. There seemed to be no danger of their being disturbed by visitors that night, but all the same they thought best to station a watchman, and Case volunteered to keep awake and see that "no one flew away with the boat," as he expressed it.

Somewhere about two o'clock in the morning, the boy, who was having hard work keeping awake, heard the puff and bellow of an approaching steamer, toiling up against the strong current. Almost at the same instant he felt a jar, as if the boat had been struck by floating driftwood. He switched on the prow light to see what was doing, but quickly extinguished it as the steamer came up and a heavy rowboat dropped away from her!