"Boom!"

"They have missed us and are firing the gun," cried Frank.

"That's what," rejoined Billy; "and we are going to get a terrible
lecture when we get back on board, too."

Soon the floe, drifting steadily southward, by the strange freak of
the antarctic current, came in view of the lookouts on the ships, who
had been posted as soon as the boys were missed. The boats were at
once despatched, and headed for the little ice island.

The killer whale suddenly took it into his head, as the boats drew
near, to try one more attack, but Dr. Watson Gregg, the ship's
surgeon, who stood in the bow of the first boat, saw the ferocious
monster coming and, with three quick bullets from a magazine rifle,
ended the great brute's career forever. His huge, black bulk, with its
whitish belly and great jaws, floated on the surface for a few
minutes, and the boys estimated his length at about thirty feet.

"Room enough there to have swallowed us all up," commented Billy, as
they gazed at the monster.

"Well, young men, what have you got to say for yourselves?" asked Dr.
Gregg, as the boats drew alongside.

The boys all looked shamefaced as they got into the boat, and two
sailors assisted the half-frozen professor into it. They realized that
they had been guilty of a breach of discipline in taking off the boat,