"I can't see any either," observed Jack. "And yet—"
There sounded the unmistakable roar of an aircraft's propeller.
"There she is!" cried some one.
But it was one of the first of a series of French planes that had hastily ascended to search the heavens for a sight of the supposed German craft that had dropped the bombs.
"What a chance we're missing!" murmured Jack.
"Yes," agreed Tom. "But they're going to have some flight before they locate that Hun. There isn't so much as a speck in the sky except the French craft."
"Let's go and see where that other explosion was," suggested Jack, when they had observed several of the French planes scurrying to and fro over the city, climbing higher and higher in search of the enemy.
"I'm with you," announced Tom. "I wonder what dad thinks of this?"
"It'll be something new for him," said Jack. "He'll have a good chance to see how his stabilizer works, if they're using it on these planes here. And maybe he can invent a better one."
"Perhaps," returned Tom. "But, Jack, do you know I'm worried about one thing."