and bounded to the after deck. The boys heard him growling threateningly for a moment, and then he came back.

Teddy, the cub, arose from the place where he had been lying, sniffed at the gunwale of the boat for an instant, and walked into the cabin.

“What’s the matter with our menagerie to-night,” demanded Alex. “There seems to be something in the air.”

“What do you see, Captain Joe?” asked Clay. “If it’s a man, and he’s got a letter, you go get it. Some other fellow may be wanting us to go South, or East, or West.”

As Clay ceased speaking, the splash of a paddle came faintly from the darkness to the West.

“Here comes R. F. D. postman number two,” shouted Alex.

As the boys listened, the splashings of the paddle came louder for a moment, then ceased entirely.

“Hello, the boat!” Alex cried. “Have you got a letter for us?”

No answer came back. There was now a break in the clouds, and the moon shone sharply down upon the swirling river, but only for an instant.

“There he comes!” cried Jule.

But the moonlight was gone, and the sound of the paddle was gone, and just at the edge of the circle of light which came from the prow, an Indian canoe glided, phantom-like, down the stream and disappeared.

CHAPTER II—A TREACHEROUS GUEST

“Do you suppose that is the fellow Captain Joe caught prowling around the stem of the boat?” asked Jule as the canoe disappeared down the river.

Captain Joe answered the question by trotting up to the prow and snarling at the disappearing canoe.

“Now, what do you think he wanted here, anyway?” asked Alex.

“Possibly he just dropped down to see if we were ready to start north,” Case observed with a yawn.

“It looks to me,” Alex said, “that we have struck a storm center of some kind, and I’m going to bed and think it over.

“I’m glad you’re going to bed,” Clay laughed, “for you get lost whenever we leave you on watch.”

“But I always find myself!” answered Alex, with a provoking grin.

It was finally arranged that Case should stand guard that night, and the others prepared for sleep. The bunks were let down in the cabin, the prow light was switched off, and directly all was dark, save when the moon broke out from a bank of wandering clouds.

Sitting well wrapped at the door of the cabin, shortly before midnight, Clay once more heard the sweep of a paddle or an oar. He arose and went to the prow.

Off to the right, on a point of land below St. Luce, a column of flame was beckoning in the gale from the gulf. Only the flame was to be seen. There was neither habitation nor human figure in sight under its light. While the boy watched, a signal shot came from the east.

Then an answering light came from the north, and a ship’s boat, four-oared and sturdy, passed for an instant under the light of the moon and was lost in the darkness.

The rowboat had passed so close to the Rambler that the watching boy could have seen the faces of the occupants if they had not been turned away. For a moment he had feared that it was the intention of the rowers to board the Rambler, but they had passed on apparently without noticing the boat at all.

After following the boat with his eyes for an instant, he switched on the prow light and turned to the cabin to awaken his chums. Here was a new feature of the night which must be considered.

As he turned toward the cabin, a white package lying upon the deck caught his eye. It had not been there a moment before, so the boy naturally concluded that it had been thrown from the row boat. He lifted it and, going back under the prow light, opened the envelope and read.

“Don’t interfere with what doesn’t concern you. Go on about your business, if you have any. Life is sweet to the young. Do you understand? Be warned. Others have tried and lost.”

The puzzled boy dashed into the cabin with the paper in his hand.

“Look here, fellows!” he shouted, pulling away at the first sleeping figure he came upon, “R. F. D. postman number two has arrived. Here’s the letter he brought.”

He read the message aloud to the three wondering boys, sitting wide-eyed on their bunks, and handed the paper to Clay.

“What about it?” he asked.

“I reckon,” Alex observed with a grin, “that we’re going to be arrested for opening some one else’s mail.”

“Don’t you ever think this letter wasn’t intended for us,” Jule declared.

“And now,” Case said, “I suppose we’ll have to give up following the orders given in the first letter. We’re ordered off the premises. See?”

“Not for mine,” Alex cried. “You can’t win me on any sawed-off mystery! I want to know what this means.”

After a time the boys switched off the prow light, turned on the small lamp in the cabin, and sat down to consider seriously the events of the night. While they talked, the clouds drifted away, and the whole surface of the river was flooded with moonlight. The flame on the south bank was seen no more. It had evidently been built as a beacon for the men in the ship’s boat.

After a time, Captain Joe, who had been sitting in the middle of the deliberative circle in the cabin, raced out to the deck. The boys heard him growling, heard a conciliatory human voice, and then a quick fall.

When the boys switched on the prow light and gained the deck, they found Captain Joe standing guard over a slender youth who had evidently fallen to the deck to escape being tumbled down by the dog. They gathered about waiting for him to speak—waiting for some explanation of his sudden appearance on the motor boat. Captain Joe seemed proud of his capture, and remained with threatening teeth within an inch of the boy’s throat.

“Say, you!” shouted Alex. “Did you come by parcel post? We’ve been getting letters all right, but no such packages as this.”

“Looks to me like he must have come in a parachute,” Jule suggested. “Where’s your boat, kid?” he added.

The visitor smiled brightly and sprang alertly to his feet. He looked from face to face for a moment, smiling at each in turn, and then pointed to a light canoe bumping against the hull of the Rambler.

He was a lad of, perhaps, eighteen, slender, lithe, dark. His clothing was rough and not too clean. His manner was intended to be ingratiating, but was only insincere.

“What about you?” demanded Alex. “Do you think this is a passenger boat?”

“A long time ago,” replied the visitor, speaking excellent English, “I read of the Rambler and her boy crew in the Quebec newspapers. When I saw the boat here to-night, I ran away from my employer and came out to you. I want to go with you wherever you are going.”

“You’ve got your nerve!” Alex cried.

“Oh, let him alone,” Case interposed. “We’ve had a stranger with us on every trip, so why not take him along?”

Alex took the speaker by the arm and walked with him back to the cabin.

“Say,” he said then, “this fellow may be all right, but I don’t like the looks of his map.”

“You’ll wash dishes a week for that,” Case announced. “You’re getting so you talk too much slang. Anyway, you shouldn’t say ‘map’—that’s common. Say you don’t like his dial.”

“Oh, I guess I’ll have plenty of help washing dishes,” Alex grunted. “But what are we going to do with this boy?” he added.

Clay now joined the two boys in the cabin and asked the same question.

“It is my idea,” he said, “that the appearance of this lad is in some way connected with the other events of the night.”

“What did you find out about him?” asked Clay.

“He says his