"This is extraordinary, young man!" exclaimed the officer of the police, for such the man was. "I think you had better explain."

"I am in a great hurry, sir," pleaded Dave.

"He wants to catch his father before the expedition leaves Christiania," put in Roger.

"Before it leaves?"

"Yes."

The police official drew up his shoulders and made a wry face.

"Has it left already?" questioned Dave, eagerly.

"To be sure—four days ago," was the answer, which filled Dave's heart with fresh dismay.