The Thinking Machine didn't say. He paused at a window, and for minute after minute stood motionless there, with eyes narrowed to mere slits.
"I was on the point of discharging Miss Winthrop," the financier went on, "but her innocence was so thoroughly proved to me by this last affair that it would have been unjust, and so – "
Suddenly the scientist turned upon his visitor. "Do you talk in your sleep?" he demanded.
"No," was the prompt reply. "I had thought of that too. It is beyond all ordinary things, Professor. Yet there is a leak that is costing me millions."
"It comes down to this, Mr. Grayson," The Thinking Machine informed him crabbedly. "If only you and Miss Winthrop knew those plans, and no one else, and they did leak, and were not deduced from other things, then either you or she permitted them to leak, intentionally or unintentionally. That is as pure logic as two and two make four; there is no need to argue it."
"Well, of course, I didn't," said Grayson.
"Then Miss Winthrop did," declared The Thinking Machine finally, positively; "unless we credit the opposition, as you call it, with telepathic gifts hitherto unheard of. By the way, you have referred to the other side only as the opposition. Do the same men, the same clique, appear against you all the time, or is it only one man?"
"It's a clique," explained the financier, "with millions back of it, headed by Ralph Matthews, a young man to whom I give credit for being the prime factor against me." His lips were set sternly.
"Why?" demanded the scientist.
"Because every time he sees me he grins," was the reply. Grayson seemed suddenly discomfited.
The Thinking Machine went to a desk, addressed an envelope, folded a sheet of paper, placed it inside, then sealed it. At length he turned back to his visitor. "Is Miss Winthrop at your office now?"
"Yes."
"Let us go there, then."
A few minutes later the eminent financier ushered the eminent scientist into his private office on the Street. The only person there was a young woman – a woman of twenty-six or-seven, perhaps – who turned, saw Grayson, and resumed reading. The financier motioned to a seat. Instead of sitting, however, The Thinking Machine went straight to Miss Winthrop and extended a sealed envelop to her.
"Mr. Ralph Matthews asked me to hand you this," he said.
The young woman glanced up into his face frankly, yet with a certain timidity, took the envelope, and turned it curiously in her hand.
"Mr. Ralph Matthews," she repeated, as if the name was a strange one. "I don't think I know him."
The Thinking Machine stood staring at her aggressively, as she opened the envelope and drew out the sheet of paper. There was no expression save surprise – bewilderment, rather – to be read on her face.
"Why, it's a blank sheet!" she remarked, puzzled.
The scientist turned suddenly toward Grayson, who had witnessed the incident with frank astonishment in his eyes. "Your telephone a moment, please," he requested.
"Certainly; here," replied Grayson.
"This will do," remarked the scientist.
He leaned forward over the desk where Miss Winthrop sat, still gazing at him in a sort of bewilderment, picked up the receiver, and held it to his ear. A few moments later he was talking to Hutchinson Hatch, reporter.
"I merely wanted to ask you to meet me at my apartment in an hour," said the scientist. "It is very important."
That was all. He hung up the receiver, paused for a moment to admire an exquisitely wrought silver box – a "vanity" box – on Miss Winthrop's desk, beside the telephone, then took a seat beside Grayson and began to discourse almost pleasantly upon the prevailing meteorological conditions. Grayson merely stared; Miss Winthrop continued her reading.
Professor Augustus S. F. X. Van Dusen, distinguished scientist, and Hutchinson Hatch, newspaper reporter, were poking round among the chimney pots and other obstructions on the roof of a skyscraper. Far below them the slumber-enshrouded city was spread out like a panorama, streets dotted brilliantly with lights, and roofs hazily visible through mists of night. Above, the infinite blackness hung like a veil, with starpoints breaking through here and there.
"Here are the wires," Hatch said at last, and he stooped.
The Thinking Machine knelt on the roof beside him, and for several minutes they remained thus in the darkness, with only the glow of a flashlight to indicate their presence. Finally, The Thinking Machine rose.
"That's the wire you want, Mr. Hatch," he said. "I'll leave the rest of it to you."
"Are you sure?" asked the reporter.
"I am always sure," was the tart response.
Hatch opened a small handsatchel and removed several queerly wrought tools. These he spread on the roof beside him; then, kneeling again, began his work. For half an hour he labored in the gloom, with only the flashlight to aid him, and then he rose.
"It's all right," he said.
The Thinking Machine examined the work that had been done, grunted his satisfaction, and together they went to the skylight, leaving a thin, insulated wire behind them, stringing along to mark their path. They passed down through the roof and into the darkness of the hall of the upper story. Here the light was extinguished. From far below came the faint echo of a man's footsteps as the watchman passed through the silent, deserted building.