"And I wonder where Jimmie and Leroy are?" Harry reflected. "There is only one person on the machine, and that must be Ned."

Jack was about to throw open the top panels when he caught sight of the aeroplane again, nearer to the water than before.

"What's Ned doing?" he asked, pointing upward.

"Talking!" exclaimed Frank.

"Wigwagging!" Harry broke out. "Now, let us see what he says."

Slowly to the right and left, up and down, an electric bulb flashed in the sky. Harry counted.

"That's C;" he said, "and that's 'a,' and that's 'u,' and that's 't,' and now 'i,' and 'o,' and 'n.' 'Caution!' That means that we've got to stand pat for a time yet."

"It also means," Jack said, "that we've made no mistake about that being the Nelson, with a Boy Scout on board. Those wigwag signals show the supposition to be true."

"Well," Harry puzzled, "he wouldn't be sending us a warning from the sky if there wasn't some danger we were not aware of. There is something going on that we are not wise to."

There was a short silence on board and then Frank remarked:

"We must be nearer the falls than we thought, for the water seems to be a ripple about us. Rear it! I'm going to look out and see it looks like."

In a moment he was jamming the panel shut and springing the slides over the loopholes and the ventilators.

Jack sprang to the prow, not knowing what danger threatened, but obeying the sudden gestures of his chum to close every opening.

Before he sprung the steel panel over the ventilator he glanced out on the river.

"Great heavens!" he cried. "Get your guns, boys!"

The whole surface of the stream, as far as the boy's eyes reached, seemed covered with savage heads, floating, drifting, down upon the Black Bear.

CHAPTER XVI

RED FIRE FROM THE SKY

Under the light of the moon the rushing river seemed full of leering, cruel eyes. The bodies of the swimming savages were not visible--only the upturned faces and the threatening eyes, with now and then a hand or the point of a glistening shoulder. There appeared to be thousands of the cannibals; their ma.s.s reaching from sh.o.r.e to sh.o.r.e.

Then, while the boys looked, expecting every instant to hear the sound of feet outside the panels, a rocket shot out from the Nelson and a score of parti-colored b.a.l.l.s curved and hissed toward the earth.

"Gee!" Jack cried. "He's giving them a fourth-of-July celebration!"

"Hope it scares them off," said Harry.

Looking through the heavy gla.s.s panel at the top, they saw a rain of red fire drop down on the swirling river. For a moment the whole upper air, then river and forest, was painted a b.l.o.o.d.y red by the burning powder.

Cries came from the river, and the ma.s.s of floating heads parted and swung swiftly toward the sh.o.r.es; then silence. The aeroplane circled about cautiously and then dropped down lower. Jack opened the panel.

"h.e.l.lo the boat!" cried a voice from the aviator's seat.

"h.e.l.lo, Ned!" all three boys called back.

"How do you know it's Ned?" was asked.

"We saw that beautiful face of yours in the red fire," replied Jack.

"How are we going to get out of here? They've blockaded the river below, and the falls are above."

"I presume I have dynamite enough to blow up that improvised dam,"

replied Ned. "Why didn't you do it?"

Before Jack could explain the situation, the Nelson drifted past, and he knew that his voice would not carry to her.

"I'm going to open up now," Harry said, as the Nelson drifted out of range of the gla.s.s pane. "I'm pretty near choked in here."

"Nice time we would have had in the Wolf," laughed Jack.

"Anyway," urged Harry, "we should have been in her in a minute if the Nelson hadn't shown up. Say, won't they give us the laugh in New York? Came away off out here alone, and then had to be rescued by Ned!"

Very cautiously the panels giving on the stern were opened. There were no savages in view. The banks of the stream seemed as quiet and harmless as a thicket in Central Park.

"I guess the rocket and the red fire got them!" grinned Frank.

"Yes, but they won't stay scared forever!" Harry put in. "We'd better be getting out of this before they come back to their senses."

"They never had any senses!" claimed Jack.

Looking out from the interior, now guarded only by the panels at the front and sides, the boys saw Ned drop half a dozen sticks of dynamite on the logs and brush which had been floated down on top of a number of canoes. In some places the logs had pushed up until they were high above the surface of the water.

The pressure of the current was continually making the obstruction more compact. The canoes seemed to have been bound firmly together and stretched from sh.o.r.e to sh.o.r.e. At least the moorings were strong, for the logs were heavy and the current pulled heavily at them.

The explosions made great havoc with the barricade, and presently the line was broken and the whole ma.s.s swung sh.o.r.eward or drifted down stream.

Then Ned called out:

"Now drop down stream and I will join you."

"Better look out where you land!" Harry called back.

"I hope I won't get into any such sc.r.a.pe as you did," Ned replied.

"Oh, you're not out of it yet!" laughed Frank. "These woods are full of man-eaters. Look out where you go, and we'll find a place for you to come down."

The anchor of the Black Bear was lifted and the power turned on. In a minute she was going down stream at a thirty-mile gait.

Directly they pa.s.sed the wrecked barricade, rolling and tumbling in the waters, the canoes either broken or half full of water. The Nelson still led the way down the stream.