"Gee whiz! almost twelve o'clock," exclaimed Hiram Nelson, looking up at the clock from the dining-room table in Paul Perkins' house. The chamber was strewn with text books on model aeroplane construction and littered with figures and plans of the boys' own devising. "How time flies when you're on a subject that interests you."

"Yes, it's a good thing it's vacation time," agreed Paul. "We wouldn't be in much shape to work at our books to-morrow, eh?"

"I should say not!" rejoined Hiram with conviction. "Well, so long, Paul. I guess we've got it all figured out now, and all that is left to do is to go ahead."

"That's the idea," responded Paul. "We'll get the prize for the glory of the Eagle Patrol, or—or—"

"Bust!" Hiram finished for him.

Hiram's way home lay past the bank, and as he walked down the moonlit street he thought for a minute that he perceived a light in the windows of the armory.

Almost as he fancied he glimpsed it, however, it vanished, and the lad was convinced that he must have been mistaken, or else seen a reflection of the moonlight on the windows.

"Queer, though," he mused. "I could almost have sworn it was a light."

Another curious thing presently attracted his attention. As he neared the bank a dark figure seemed to vanish into the black shadows round the corner. Something familiar about it struck Hiram, and the next moment he realized why.

"If that wasn't Bill Bender, I'm a Dutchman," he muttered, his heart beating a little faster. "But what can he be doing round here at this time of night?"