“Well, we’ll soon be back in Uncle Sam’s land,” declared Tom.  “We can go back on board the Falcon to sleep shortly.  Jove!  I wish I could have caught those fellows!”

“Never mind, we’ll get ’em yet,” counseled Mr. Whitford.

Waiting until he was sure all the vapor had disappeared, Tom led the way back to the Falcon.  No great harm had been done, save to lose considerable gas, and this could be remedied.  Tired and disappointed from the chase, they sought their bunks, and were soon asleep.  In the morning Tom and Ned began work on the clogged pipes.

This work was nearly accomplished by noon, when Mr. Damon, coming back from a stroll, announced that they were but fifteen minutes walk from the St. Lawrence River, as he had seen the sparkling waters from a neighboring hill.

“Let’s go over and have a look at it,” proposed Ned.  “We can easily finish this when we get back.  Besides, Tom, we don’t want to get to our regular camp until after dark, anyhow.”

The young inventor was willing, and the two lads, with Mr. Whitford, strolled toward the historic stream.  As they drew near the bank, they saw, anchored a little distance out, a small steamer.  Approaching it, as if she had just left the shore at a point near where our friends stood, was a gasolene launch, containing several men, while on shore, in front of a small shanty, stood another man.

This latter individual, at the sight of Tom, Ned and Mr. Whitford, blew a shrill whistle.  Those in the launch looked back.  The man on shore waved a red flag in a peculiar way, almost as the soldiers in the army wig-wag signals.

In another moment the launch turned about, and put for shore, while the lone man hurried back into the hut.

“Hum!” remarked Tom.  “Those are queer actions.”

“Suspicious actions, I should say,” said Mr. Whitford.  “I’m going to see what this means.”

CHAPTER XXI

MR. PERIOD ARRIVES

Greatly interested in what was about to take place, and not a little suspicious, our friends stood on the bank of the river and watched the motor boat returning.  As it reached a little dock in front of the hut, the man who had waved the red flag of warning came out, and talked rapidly to those in the power craft.  At the same time he pointed occasionally to Tom, Ned and the government agent.

“This is getting interesting,” remarked Mr. Whitford.  “We may have accidentally stumbled on something important Tom.”

“See, they’re signalling to the steamer now,” spoke Ned, and, as he said this, his companions looked, and noted the man from the hut waving a white flag, in a peculiar manner.  His signals were answered by those on the vessel anchored out in the stream, and, a little later, black smoke could be seen pouring from her funnel.

“Looks as if they were getting ready to leave,” spoke Tom.