It was midnight when, far down in the rock-hewn cavern in which the Automaton had his secret den, the steel monster and one of his men stalked out through the arched passage that led to the very cellar of the house above them.
A few moments later the swinging rock door in the Graveyard of Genius tilted and the two entered the strong-room, passing across the room and out through the steel door into the cellar. Up the cellar steps they proceeded until they reached the hall, then noiselessly they crossed into the library. With his human companion the monster approached the safe deliberately. Just as deliberately the Automaton reached out to turn the handle of the combination.
There was a flash as the current passed through the arm of steel to the foot of steel resting on the plate Locke had set in the floor. A suppressed cry escaped from the henchman. As for the monster, he strove with superhuman force to wrench himself away from the electric trap.
Meanwhile, up in his laboratory in the house, Locke and four men from the Department of Justice had been waiting.
"The Department expects us to get this evidence right," he had emphasized as he gave them their instructions.
Hardly had he finished when a signal light which Locke had arranged on the wall flashed, giving the information that the trap had worked.
Out of the laboratory all piled, running down the hall, Locke paused only a second to tap on Eva's door, as she had asked, if anything happened, so that she might be present at the capture. An instant and Eva, too, had joined the pursuit.
Down in the library the Automaton struggled with the current. As the rug was kicked aside, the emissary saw the wire from the plate and quickly traced it to its source.
The result was that in a few seconds the emissary had found a wall switch and pulled it. Instantly the Automaton was released from the power that held him.
Quickly the man of steel raised and lowered his arms, as though to be sure that he could do so, at the same time indicating orders to his follower, who leaped to guard the entrance to the room. Then the Automaton turned to open the safe, making swift use of the remaining seconds before the alarm might bring interference.