Bob promised, and without delay Captain Sumner started on the return to the Dart.
With a wildly beating heart Bob watched the people who held his father a captive.
They were marching along silently now and did not stop until the center of the cave of ice was reached.
Here the party assembled in a circle at a point where there was a slight elevation.
Two of the men had axes, and with these they began to chop at the elevation, causing the pieces of ice to fly in all directions.
"Now what are they going to do?" thought our hero.
Presently he heard a slight noise behind him. Somewhat startled, he turned around to find himself face to face with a monstrous polar bear!
The beast had just discovered Bob. For a moment he stood still.
Then with a growl he leaped directly for the astonished youth.
Had Bob not sprung out of the way the bear would have landed on his head.