He drew a little case from his coat pocket.
"Just as well, perhaps," he said softly to himself, "that I perfected this instrument.

It's rather close quarters here." He opened what seemed to be a little mahogany box, looked at the ball of black substance inside, closed it up, placed it against the far wall, untwisted the coil, stood back near the door and pressed the button.

The result was extraordinary.

The whole of the far wall was blown out and for some distance in front the ground was furrowed up by the explosion.

Quest replaced the instrument in his pocket, sprang through the opening and ran for the tower house.