The thick planks were tightly spiked down.

Nor did the walls offer any better encouragement.

Keith lifted himself to the grated window, getting a glimpse of the world without, but finding the iron immovable, the screws solidly imbedded in the outside wood.

He dropped to the floor, feeling baffled and discouraged.
"It will have to be the plank back of the bench, Neb," he announced briefly, wiping the perspiration from his face.

"Get down there, and work it as loose as you can without making any noise, while I keep my ear to the door and listen for any interruption." They took turns at this labor, discovering a loose nail which gave an opening purchase at the crack, thus enabling the insertion of a small wooden block, and insuring space for a good finger grip when the right time came.