At the sound of the English phrase the German lieutenant, who had been watching the friends embark for their aerial trip, realized in a moment that he had been fooled.
The plane was gliding slowly across the ground when he called to his men:
"Spies! Shoot them!"
Instantly the soldiers threw their rifles to their shoulders and poured a volley after the plane. Then they started after the craft on a dead run.
The first volley did no damage beyond arousing Hal's anger. He berated Stubbs' carelessness roundly to himself, but not for a moment did he take his mind off the work in hand.
Chester and Stubbs ducked instinctively at the sound of the first volley. Then Chester raised his head, and drawing his revolvers, fired at the pursuing Germans.
The lad's efforts were rewarded with cries of anger, and there was one shrill scream. Chester smiled grimly to himself, for he knew that he had accounted for one of the foes.
Again and again the Germans fired, and Chester heard the balls glance off the side of the plane. Still the enemy fire had not reached a vital part of the craft and the occupants were untouched.
Now Hal touched the elevating lever gently and the plane soared in the air. One more volley the Germans fired after them. Then the three friends were safe.
"Stubbs," said Chester, as the plane sped through the air. "I ought to pitch you out of here, and you know it."