“Get your revolver, quick!” called Jerry. “There is some one in the hut besides ourselves! Look over by the fire!”

“I see it! Shall I shoot?” asked Ned.

There came a sudden crash, followed by a wild yell.

“Help! Help! I’m killed! They are murdering me!” shouted Bob’s voice. “They are choking me to death!”

Bang! went Ned’s gun.

Fortunately it was aimed at the ceiling, or some one might have been hurt.

“What’s the trouble?” inquired the professor, who only just then awoke.

“Robbers!” yelled Bob.

“Brigands!” exclaimed Ned.

“Some one is in the cabin!” cried Jerry.