see, Mr. Wall, that's the mirage and nothing
else."

"You are right, Dr. Clawbonny," replied Johnson; "they've all been
frightened by a shadow."

When they had heard what the doctor said, most of the sailors drew
near him, and from terror they turned to admiration of this wonderful
phenomenon, which soon passed from their view.

"They call that a mirage," said Clifton; "the Devil's at the bottom of
it, I'm sure."

"That's true," growled Gripper.

But the break in the fog had given the commander a glimpse of a broad
passage which he had not expected to find; it promised to lead him
away from the shore; he resolved to make use of it at once; men were
sent out on each side of the canal; hawsers were given them, and they
began to tow the ship northward.

During long hours this work was prosecuted busily but silently;
Shandon had the furnace-fires lighted to help him through this passage
so providentially discovered.

"That's great luck," he said to Johnson, "and if we can only get on a
few miles, we may be free. Make a hot fire, Mr. Brunton, and let me
know as soon as you get steam on. Meanwhile, men, the farther on we
get, the more gained! You want to get away from the Devil's Thumb;
well, now is your chance!"

Suddenly the brig stopped. "What's the matter?" shouted Shandon.
"Wall, have the tow-ropes broken?"

"No," answered Wall, leaning over the railing. "See, there are the men
running back; they are climbing on board; they seem very much
frightened."

"What's happened?" cried Shandon, running forward.

"On board, on board!" cried the sailors, evidently exceedingly
terrified.

Shandon looked towards the north, and shuddered in spite of himself.

A strange animal, with alarming motions, whose steaming tongue hung
from huge jaws, was bounding along within a cable's length from the
ship; it seemed more than twenty feet high; its hair stood on end; it
was chasing the sailors as if about to seize them, while its tail,
which was at least ten feet long, lashed the snow and tossed it about
in dense gusts. The sight of the monster froze the blood in the veins
of the boldest.

[Illustration: "A strange animal was bounding along within a cable's
length from the ship."]

"It's an enormous bear," said one.

"It's the beast of Gevaudan!"

"It's the lion of the Apocalypse!"

Shandon ran to his cabin to get a gun which he kept always loaded; the
doctor seized his arms, and made ready to fire at the beast, whic