“No,” replied Chester.
“I’ll be careful next time,” said Hal. “You’ll have to forgive me this once.”
“Say no more about it,” answered Chester. “But what was the cause of this sudden rise?”
“Cause!” repeated Hal in astonishment. “You don’t mean to tell me you don’t know the cause? Didn’t you hear that shot?”
“Yes, I heard it. But how do you know whether it was fired by friend or foe?”
“I can’t see as that would make any difference if it happened to hit us. However, I’m morally certain they were Germans.”
“Well, maybe they were. What are we going to do now?”
“We’ll stay up here until we are absolutely certain we have passed over the German lines. Then we’ll come down.”
The machine was high in the air now, and, peering intently over the side, as he did, Chester was unable to make out anything below in the early morning light.
But in the rear, soaring high in the air, although neither lad realized it, a new danger threatened. When the presence of the boys’ plane had been discovered, a German craft had immediately risen, and was now in pursuit.