av a camp, Frankie?"

"Not a sign of a camp or a human being. This is rather strange."

A strange feeling of wonder that swiftly changed to awe was creeping
over them. The canoe was snowy white, and lay perfectly motionless on
the still surface of the water. It was in the dark shadow beneath the
trees.

"Perhaps the owner of the canoe is lying in the bottom," suggested the
professor.

"We'll see about that," said Frank, putting down the bow and arrow and
taking up a paddle. "Head straight for her, Barney."

With the very first stroke in that direction a most astonishing thing
happened.

The white canoe seemed to swing slightly about, and then, with no
visible occupant and no apparent motive power, it glided smoothly and
gently toward the dark depths of the black forest!

"She's floating away from us!" cried the professor. "There must be a
strong current there!"

"Nivver a bit is she floating!" gasped Barney Mulloy. "Will ye look at
her go! Begobs! Oi fale me hair shtandin' on me head!"

"She is not floating!" Frank said. "See--she gains speed! Look at the
ripple that spreads from her prow!"

"But--but," spluttered Professor Scotch, "what is making her move--what
is propelling her?"

"That's a mystery!" came from Frank, "but it's a mystery I mean to
solve! Get out your paddle, professor. Keep straight after that canoe,
Barney. We'll run her down and look her over."

Then a strange race began, canoe against canoe, the one in the lead
apparently empty, the one pursuing containing three persons who were
using all their strength and skill to overtake the empty craft.

[Illustration: "The white canoe had stopped, and was lying calmly on the
inky surface of the shadowed water." (See page 147)]

CHAPTER XXVI.

STILL MORE MYSTERIOUS.

"Pull!" panted Frank.

"Pull!" mumbled the professor.

"Pull!" snorted Barney, in disgust, great drops of perspiration rolling
down his face. "As if we wurn't pullin'!"

"We're not gaining."

"The white canoe keeps just so far ahead."

"Begobs! it's not our fault at all, at all."

Indeed, no matter how hard they worked, no matter how fast they made the
canoe fly through the water, they could not gain on the mysterious white
canoe. The distance between the two canoes seemed to remain just the
same, and the one in advance slipped through the water without a sound,
following the winding water course beneath the dark trees and going
deeper and deeper into the hea