Very truly yours,

PETER BRENT.

Following this letter was a bulky paper, or rather set of papers, which detailed the inventions and their history, exposing some of the nefarious operations of the corporation.

Balcom, as he read the top letter, showed great agitation. As Locke took the package from Eva, Balcom interrupted:

"That's very dangerous," he said. "If it gets out, the corporations are ruined."

Locke scarcely replied. Instead, he very ostentatiously replaced the document in the safe, refusing to intrust it either to Balcom or to Paul, who withdrew sullenly, leaving Eva alone with Locke in the library as Locke whirled the combination of the closed safe door.

It was perhaps half an hour later in the secret den of the Automaton in the rock-hewn foundation of Brent Rock that the emissaries were watching the arched and dark passage. Suddenly there was the warning clank, and the huge steel monster strode in.

For some time he stood before the table, giving his instructions by means of mysterious, cryptic motions.

Meantime, above in Brent Rock, Locke had been busy, for he had conceived an entirely new plan to capture the Automaton. It was nothing short of an electric trap, and deadly in its simplicity.

From the wall switch Locke had led wires carrying the house current.

Already, also, he had let Eva in on his secret plan, and she was all eagerness as he planted his trap.

Before the safe, now, Locke paused, and there for a moment twisted the combination so that he could get his correct position. That done, he noted the place where he had been standing, and removed a mat from the floor in front of the safe. At that place he set in on the floor a fairly large iron plate. To this iron plate he attached a wire, then replaced the rug, but in such a way that a part of the plate was exposed, though it would never be noticed.

"If the Automaton attempts to open the safe," he remarked to Eva, as he worked, "he will complete the electric circuit and it will hold him until we capture him."

"How clever!" Eva exclaimed, involuntarily.

"Now for making my signaling connection to the laboratory," continued Locke. "Then I must get some of my men up here from the department."

However, while Locke and Eva were busy arranging this electric trap, they did not notice that they were being watched by Zita, who had stolen into the conservatory and was eying them eagerly from the protection of the fronds of a palm. Zita, moreover, was greatly excited, as she gathered with her quick perception just what it was that they were doing. Nor did she wait to see the work finished, but stole out of the door and away hurriedly.

Locke had finished his preparations, and as he and Eva were discussing the possibilities of what he had devised, he remarked, in answer to her eager inquiry about his suspicions, "I am sure we shall prove that there is a man inside the terrible machine that attacks us."

"Then you don't think it is really an automaton?" asked Eva, with great respect for Locke's opinion, though it was sufficiently in evidence that she was not at all convinced that the monster was not really of steel and controlled by something that resembled a human brain.

Locke was non-committal. "This trap will tell us," was all that he would say.

Zita, hurrying out from the conservatory, and wishing to waste not an instant in notifying Balcom, sought a near-by telephone pay-station, and there in frantic haste she demanded Balcom's number.

It was some moments before Central could make the connection, and then it was only to Zita's disappointment and growing fear. The Madagascan servant of Balcom answered in the absence of his master.

"Is Mr. Balcom there?" asked Zita, adding, "Or Mr. Paul?"

The black shook his head. "Neither Mr. Balcom nor Mr. Paul is at home,"

he replied.

Zita was now thoroughly alarmed. Had she some connection with the Automaton? Or was it her fear that either Balcom or Paul might know more than they would care to have the authorities know? Or was the Automaton really an iron monster, after all?

That and many other questions were surging through the minds of all who had encountered this unique mystery.

CHAPTER XI

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.

In almost no time he had the safe open, reached in, and seized a packet of precious papers, apparently. Then he turned and was gone, regardless of the man whom he had sent to guard him.

In the hall, Locke's sharp ears had detected the approach of the emissary. Not knowing whether it might be the villain himself, he cautioned the men to wait an instant. The emissary, coming along, crouching and listening, did not see Locke, and thus Locke was able to seize him and with a spectacular throw project him literally into the hands of the law in the person of one of his own men, who snapped the bracelets on the astonished thug as Locke, followed by Eva and the rest, ran on to the library.

No one was in the library as Locke ran in and looked about. He turned toward the door to the hallway where the portieres were drawn. As he was standing there, looking about, the portieres moved behind him. Suddenly they were jerked aside from their fastenings and flung over his head. As this happened, the ponderous hand of the Automaton descended on Locke's head and he sank to the floor as the portieres wrapped about him.

When the department agents with Eva arrived, they were merely in time to untangle Locke from the curtains. The Automaton had fled safely.

Although his head was still reeling from the blow, Locke started to question the prisoner, but gave it up as a bad job and hurried over to examine the safe, followed by Eva.

Their dismay was mutual. Not only was the safe door open, but the paper was gone.

Question the emissary as they would, they could get nothing out of him.

Such men have keenly developed the gang instinct of silence. They would sooner die than squeal.

Even a night in jail failed to break the reticence of the emissary, although he had been subjected to the most strenuous third degree.

Not only had his spirit not been broken, but the fellow was keenly alert and planning a way to secure his own release.

As a prison guard was taking the emissary back to his cell, after a thorough quizzing by Locke in the warden's office, the emissary whispered:

"Want to make a piece of change--safe?"

The guard looked about, saw that the coast was clear to speak, but before he could do so the emissary spoke again.