"We know the method of escape, the pursuit, and all that," continued the Professor, "therefore we jump to the return of the gold plate. Logic makes it instantly apparent that that was the work of Miss Meredith here. Not having the plate, Mr. Herbert did not send it back, of course; and the Burglar _would_ not have sent it back. Realising, too late, that the man she was with was really a thief--and still believing him, perhaps, to be Mr. Herbert--she must have taken the plate and escaped under cover of darkness?"

The tone carried a question and The Thinking Machine turned squintingly upon Dollie. Again she nodded. She was enthralled, fascinated, by the recital.

"It was a simple matter for her to return the gold plate by express, taking advantage of an unoccupied house and the willingness of a stranger to telephone for an express wagon. Thus, we have the plate again at Seven Oaks, and we have it there by the only method it could have been returned there when we account for, and consider, every known fact."

The Thinking Machine paused and sat silently staring upward. His listeners readjusted themselves in their chairs and waited impatiently.

"Now, why did Mr. Herbert confess to Miss Meredith that he stole the plate?" asked the scientist, as if of himself. "Perhaps she forced him to it. Mr. Herbert is a young man of strong loyalty and a grim sense of humour, this latter being a quality the police are not acquainted with.

However, Mr. Herbert _did_ confess to Miss Meredith that he was the Burglar, but he made this confession, obviously, because she would believe nothing else, and when a seeming necessity of protecting the real Burglar was still uppermost in his mind. What he wanted was the Girl. If the facts never came out he was all right; if they did come out they would implicate one whom he was protecting, but through no fault of his--therefore, he was still all right."

"Bah!" exclaimed the Supreme Intelligence. "My experience has shown that a man doesn't confess to a theft unless----"

"So we may safely a.s.sume," The Thinking Machine continued almost pleasantly, "that Mr. Herbert, by confessing the theft as a prank, perhaps, won back Miss Meredith's confidence; that they planned an elopement for the second time. A conversation Mr. Hatch had with Mr.

Herbert immediately after Mr. Herbert saw Miss Meredith practically confirms it. Then, with matters in this shape, the real Burglar, to whom I have accredited unusual powers, stole the plate the second time--we know how."

"Herbert stole it, you mean!" blazed Detective Mallory.

"This theft came immediately on top of the reconciliation of Miss Meredith and Mr. Herbert," The Thinking Machine went on steadily, without heeding the remark by the slightest sign. "Therefore, it was only natural that he should be the person most vitally interested in seeing that the plate was again returned. He undertook to do this himself. The result was that, where the police had failed, he found the plate and a lot of jewels, took them from the Burglar, and was about to return Mr. Randolph's property when the detectives walked in on him.

That is why he laughed."

Detective Mallory arose from his seat and started to say something impolite. The presence of Dollie Meredith choked the words back and he swallowed hard.

"Who then," he demanded after a couple of gulps--"who do you say is the thief if Herbert is not?"

The Thinking Machine glanced up into his face, then turned to Hatch.

"Mr. Hatch, what is that name I asked you to get?"

"George Francis Hayden," was the stammering reply, "but--but----"

"Then George Francis Hayden is the thief," declared The Thinking Machine emphatically.

"But I--I started to say," Hatch blurted--"I started to say that George Francis Hayden has been dead for two years."

The Thinking Machine rose suddenly and glared at the reporter. There was a tense silence, broken at last by a chuckle from Detective Mallory.

"Dead?" repeated the scientist incredulously. "Do you _know_ that?"

"Yes, I--I know it."

The Thinking Machine stood for another moment squinting at him, then, turning, left the room.

CHAPTER VII

Half an hour later The Thinking Machine walked in, unannounced, upon d.i.c.k Herbert. The front door had not been locked; Blair was somewhere in the rear. Herbert, in some surprise, glanced up at his visitor just in time to see him plank himself down solidly into a chair.

"Mr. Herbert," the scientist began, "I have gone out of my way to prove to the police that you were not in the automobile with Miss Meredith, and that you did not steal the gold plate found in your possession. Now, I happen to know the name of the thief, and----"

"And if you mention it to one living soul," d.i.c.k added suddenly, hotly, "I shall forget myself and--and----"

"His name is George Francis Hayden," the scientist continued.

d.i.c.k started a little and straightened up; the menace dropped from him and he paused to gaze curiously into the wizened face before him. After a moment he drew a sigh of deep relief.

"Oh!" he exclaimed. "Oh!"

"I know that that isn't who you thought it was," resumed the other, "but the fact remains that Hayden is the man with whom Miss Meredith unwittingly eloped, and that Hayden is the man who actually stole the plate and jewels. Further, the fact remains that Hayden----"

"Is dead," d.i.c.k supplemented grimly. "You are talking through your----"

He coughed a little. "You are talking without any knowledge of what you are saying."

"He can't be dead," remarked the scientist calmly.

"But he _is_ dead!" d.i.c.k insisted.

"He can't be dead," snapped the other abruptly. "It's perfectly silly to suppose such a thing. Why, I have proven absolutely, by the simplest rules of logic, that he stole the gold plate, therefore he cannot be dead. It's silly to say so."

d.i.c.k wasn't quite certain whether to be angry or amused. He decided to hold the matter in abeyance for the moment and see what other strange thing would develop.

"How long has he been dead?" continued the scientist.

"About two years."

"You _know_ it?"

"Yes, I know it."

"_How_ do you know it?"

"Because I attended his funeral," was the prompt reply. d.i.c.k saw a shadow of impatience flash into his visitor's face and instantly pa.s.s.

"How did he die?" queried the scientist.

"He was lost from his catboat," d.i.c.k answered. "He had gone out sailing, alone, while in a bathing-suit. Several hours after the boat drifted in on the tide without him. Two or three weeks later the body was recovered."

"Ah!" exclaimed The Thinking Machine.

Then, for half an hour or so, he talked, and--as he went on, incisively, pointedly, dramatically, even, at times--d.i.c.k Herbert's eyes opened wider and wider. At the end he rose and gripped the scientist's slender white fingers heartily in his own with something approaching awe in his manner. Finally he put on his hat and they went out together.

That evening at eight o'clock Detective Mallory, Hutchinson Hatch, Mr.

Randolph, Mr. Meredith, Mr. Greyton, and Dollie Meredith gathered in a parlour of the Greyton home by request of The Thinking Machine. They were waiting for something--no one knew exactly what.

Finally there came a tinkle at the bell and The Thinking Machine entered. Behind him came d.i.c.k Herbert, Dr. Clarence Walpole, and a stranger. Mr. Meredith glanced up quickly at Herbert, and Dollie lifted her chin haughtily with a stony stare which admitted of no compromise.

d.i.c.k pleaded for recognition with his eyes, but it was no use, so he sat down where he could watch her un.o.bserved.