The tall form of their superior had hardly vanished from the doorway before Herc, who had turned to search for some tool, gave a sudden sharp outcry.
There was a small window, high up in the rear of the shed, which had been left open for ventilation. As Herc turned, he was as certain as he was that it was daylight, that he had seen a face vanish quickly from the casement. Its owner had evidently dropped from the opening through which he had chosen to spy on the Dreadnought Boys.
"What's up, Herc?" asked Ned, as he caught his chum's smothered exclamation.
"Why—why," exclaimed Herc, "I could be almost certain that I saw the face of Chance vanish from that window as I turned round."
"Eavesdropping, eh?"
"Looks like it. I guess he saw Lieutenant De Frees come in here and remain longer than ordinarily. It must have aroused their curiosity."
"What do you mean by 'they'?"
"Merritt and Chance, of course. You know how much love they bear us. I guess they felt afraid we were stealing a march of some kind on them.
"It's a mean trick!" continued Herc. "If I'd only caught him before I'd—I'd have bust his face."
"Let's go round to the back of the shed. We can soon find out if anyone was really there, or if your imagination played you a trick."