"Be careful!" warned The Thinking Machine.

They went along the hall to a room in the rear, and still the wire trailed behind. At the last door they stopped. The Thinking Machine fumbled with some keys, then opened the way. Here an electric light was on. The room was bare of furniture, the only sign of recent occupancy being a telephone instrument on the wall.

Here The Thinking Machine stopped and stared at the spool of wire which he had permitted to wind off as he walked, and his thin face expressed doubt.

"It wouldn't be safe," he said at last, "to leave the wire exposed as we have left it. True, this floor is not occupied; but someone might pa.s.s this way and disturb it. You take the spool, go back to the roof, winding the wire as you go, then swing the spool down to me over the side of the building, so that I can bring it in through the window. That will be best. I will catch it here, and thus there will be nothing to indicate any connection." Hatch went out quietly and closed the door.

Twice the following day The Thinking Machine spoke to the financier over the telephone. Grayson was in his private office, Miss Winthrop at her desk, when the first call came.

"Be careful in answering my questions," warned The Thinking Machine when Grayson answered. "Do you know how long Miss Winthrop has owned the little silver box which is now on her desk, near the telephone?"

Grayson glanced round involuntarily to where the girl sat idly turning over the leaves of her book. "Yes," he answered, "for seven months. I gave it to her last Christmas."

"Ah!" exclaimed the scientist. "That simplifies matters. Where did you buy it?"

Grayson mentioned the name of a well-known jeweler.

Considerably later in the day The Thinking Machine called Grayson to the telephone again.

"What make of typewriter does she use?" came the querulous voice over the wire.

Grayson named it.

While Grayson sat with deeply perplexed lines in his face, the diminutive scientist called upon Hutchinson Hatch at his office.

"Do you use a typewriter?" demanded The Thinking Machine.

"Yes."

"What kind?"

"Oh, four or five kinds--we have half a dozen different makes in the office."

They pa.s.sed along through the city room, at that moment practically deserted, until finally the watery blue eyes settled upon a typewriter with the name emblazoned on the front.

"That's it!" exclaimed The Thinking Machine. "Write something on it," he directed Hatch.

Hatch drew up a chair and rolled off several lines of the immortal practice sentence, beginning, "Now is the time for all good men--"

The Thinking Machine sat beside him, squinting across the room in deep abstraction, and listening intently. His head was turned away from the reporter, but his ear was within a few inches of the machine. For half a minute he sat there listening, then shook his head.

"Strike your vowels," he commanded; "first slowly, then rapidly."

Again Hatch obeyed, while the scientist listened. And again he shook his head. Then in turn every make of machine in the office was tested the same way. At the end The Thinking Machine rose and went his way. There was an expression nearly approaching complete bewilderment on his face.

For hour after hour that night The Thinking Machine half lay in a huge chair in his laboratory, with eyes turned uncompromisingly upward, and an expression of complete concentration on his face. There was no change either in his position or his gaze as minute succeeded minute; the brow was deeply wrinkled now, and the thin line of the lips was drawn taut.

The tiny clock in the reception room struck ten, eleven, twelve, and finally one. At just half-past one The Thinking Machine rose suddenly.

"Positively I am getting stupid!" he grumbled half aloud. "Of course! Of course! Why couldn't I have thought of that in the first place?..."

So it came about that Grayson did not go to his office on the following morning at the usual time. Instead, he called again upon The Thinking Machine in eager, expectant response to a note which had reached him at his home just before he started to his office.

"Nothing yet," said The Thinking Machine as the financier entered. "But here is something you must do today. At one o'clock," the scientist went on, "you must issue orders for a gigantic deal of some sort; and you must issue them precisely as you have issued them in the past; there must be no variation. Dictate the letters as you have always done to Miss Winthrop--_but don't send them_! When they come to you, keep them until you see me."

"You mean that the deal must be purely imaginative?" inquired the financier.

"Precisely," was the reply. "But make your instructions circ.u.mstantial; give them enough detail to make them absolutely logical and convincing."

Grayson asked a dozen questions, answers to which were curtly denied, then went to his office. The Thinking Machine again called Hatch on the telephone.

"I've got it," he announced briefly. "I want the best telegraph operator you know. Bring him along and meet me in the room on the top floor where the telephone is at precisely fifteen minutes before one o'clock today."

"Telegraph operator?" Hatch repeated.

"That's what I said--telegraph operator!" replied the scientist irritably. "Goodbye."

Hatch smiled whimsically at the other end as he heard the receiver banged on the hook--smiled because he knew the eccentric ways of this singular man, whose mind so accurately illuminated every problem to which it was directed. Then he went out to the telegraph room and borrowed the princ.i.p.al operator. They were in the little room on the top floor at precisely fifteen minutes of one.

The operator glanced about in astonishment. The room was still unfurnished, save for the telephone box on the wall.

"What do I do?" he asked The Thinking Machine.

"I'll tell you when the time comes," responded the scientist, as he glanced at his watch.

At three minutes of one o'clock he handed a sheet of blank paper to the operator, and gave him final instructions.

There was ludicrous mystification on the operator's face; but he obeyed orders, grinning cheerfully at Hatch as he tilted his cigar up to keep the smoke out of his eyes. The Thinking Machine stood impatiently looking on, watch in hand. Hatch didn't know what was happening, but he was interested.

At last the operator heard something. His face became suddenly alert. He continued to listen for a moment, and then came a smile of recognition.

Less than ten minutes after Miss Winthrop had handed over the typewritten letters of instruction to Grayson for signature, and while he still sat turning them over in his hands, the door opened and The Thinking Machine entered. He tossed a folded sheet of paper on the desk before Grayson, and went straight to Miss Winthrop.

"So you did know Mr. Ralph Matthews after all?" he inquired.

The girl rose from her desk, and a flash of some subtle emotion pa.s.sed over her face. "What do you mean, sir?" she demanded.

"You might as well remove the silver box," The Thinking Machine went on mercilessly. "There is no further need of the connection."

Miss Winthrop glanced down at the telephone extension on her desk, and her hand darted toward it. The silver "vanity" box was directly under the receiver, supporting it, so that all weight was removed from the hook, and the line was open. She s.n.a.t.c.hed the box and the receiver dropped back on the hook. The Thinking Machine turned to Grayson.

"It was Miss Winthrop," he said.