"I trust so, too," added Mr. McKay. "Now, let us see if there's anything else of interest here. I am anxious to examine these murderous devices. Ah!"
Mr. McKay pointed in the direction of the shattered door. On either side, but separated from the entrance tunnel by a massive wall composed of the solid rock, was a narrow and lofty passage, both running parallel with the tunnel.
Lantern in hand, Mr. McKay stooped down and entered the right-hand recess, and to his surprise he found no fewer than six steel lances, each accompanied by a tightly coiled spring, while a seventh had uncoiled itself, the spiral spring stretching from wall to wall.
"Great heavens!" he exclaimed with thankfulness. "We've had a fortunate escape. Each of these fiendish contrivances is set to launch itself into the tunnel on the outside of the door. The one we released is the nearest."
"Then we must have passed them?" asked Andy.
"Yes, and by the intervention of Providence they failed to act. Watch!"
And touching a slender steel rod that passed from the front of one of the springs to the floor, Mr. McKay gave it a sharp upward jerk.
Instantly the hidden coil released itself, and the dread weapon disappeared through the rock which separated the cave-like recess from the tunnel.
"The whole contrivance, though deadly, is comparatively simple," explained Mr. McKay. "Underneath the floors of both chambers are a number of levers. The weight of a person treading in the tunnel would cause the lever to move a rod, which in turn releases a finely set trigger which controls the springs. Owing to years of idleness the levers failed to act, and only Andy's continuous exertions as he lay on the ground in front of the door caused one of the springs to be released. I bargained for one, but not a dozen or more, by Jove!"
"A dozen?" echoed Terence.