Thinking of these things and with his head full of the plans for discovering the secret of the happenings at Glen Springs, he walked round the works again, viewing the emplacements and the big guns, but with his thoughts far enough away from the things on which his eyes rested.
Suddenly he was attracted by a cry.

It seemed to come from the air, and it made him think of the apparition and the ghostly footsteps.

But when he glanced up he saw Danny Griswold's head protruding from the muzzle of a large coast-defense cannon.

Merriwell was astonished, though such a piece of recklessness was just like Danny.

It was not that Frank feared any peril to Danny from the gun, but the officers and gunners would be indignant, no doubt, if they caught the little joker playing hide-and-seek in that way with one of their pets.
"I'll give him a scare," he thought.