President Fraser called Professor Van Dusen-The Thinking Machine-and talked for a moment through the 'phone. Then he turned back to West.
"He'll come," he said, with an air of relief. "I was able to do him a favor once by putting an invention on the market."
Within an hour The Thinking Machine, accompanied by Hutchinson Hatch, reporter, appeared. President Fraser knew the scientist well, but on West the strange figure made a startling, almost uncanny, impression. Every known fact was placed before The Thinking Machine. He listened without comment, then arose and wandered aimlessly about the offices. The employees were amused by his manner; Hatch was a silent looker-on.
"Where was the handkerchief found?" demanded The Thinking Machine, at last.
"Here," replied West, and he indicated the exact spot.
"Any draught through the office-ever?"
"None. We have a patent ventilating system which prevents that."
The Thinking Machine squinted for several minutes at the window which had been unfastened-the window in the cashier's private room-with the steel bars guarding it, now torn out of their sockets, and at the chalklike softness of the granite about the sockets. After awhile he turned to the president and cashier.
"Where is the handkerchief?"
"In my desk," Fraser replied. "The police thought it of no consequence, save, perhaps-perhaps--," and he looked at West.
"Except that it might implicate me," said West, hotly.
"Tut, tut, tut," said Fraser, reprovingly. "No one thinks for a--"
"Well, well, the handkerchief?" interrupted The Thinking Machine, in annoyance.
"Come into my office," suggested the president.
The Thinking Machine started in, saw a woman-Miss Clarke, who had returned from luncheon-and stopped. There was one thing on earth he was afraid of-a woman.
"Bring it out here," he requested.
President Fraser brought it and placed it in the slender hands of the scientist, who examined it closely by a window, turning it over and over. At last he sniffed at it. There was the faint, clinging odor of violet perfume. Then abruptly, irrelevantly, he turned to Fraser.
"How many women employed in the bank?" he asked.
"Three," was the reply; "Miss Clarke, who is my secretary, and two general stenographers in the outer office."
"How many men?"
"Fourteen, including myself."
If the president and Cashier West had been surprised at the actions of The Thinking Machine up to this point, now they were amazed. He thrust the handkerchief at Hatch, took his own handkerchief, briskly scrubbed his hands with it, and also passed that to Hatch.
"Keep those," he commanded.
He sniffed at his hands, then walked into the outer office, straight toward the desk of one of the young women stenographers. He leaned over her, and asked one question:
"What system of shorthand do you write?"
"Pitman," was the astonished reply.
The scientist sniffed. Yes, it was unmistakably a sniff. He left her suddenly and went to the other stenographer. Precisely the same thing happened; standing close to her he asked one question, and at her answer sniffed. Miss Clarke passed through the outer office to mail a letter. She, too, had to answer the question as the scientist squinted into her eyes, and sniffed.
"Ah," he said, at her answer.
Then from one to another of the employees of the bank he went, asking each a few questions. By this time a murmur of amusement was running through the office. Finally The Thinking Machine approached the cage in which sat Dunston, the receiving teller. The young man was bent over his work, absorbed.
"How long have e you been employed here?" asked the scientist, suddenly.
Dunston started and glanced around quickly.
"Five years," he responded.
"It must be hot work," said The Thinking Machine. "You're perspiring."
"Am I?" inquired the young man, smilingly.
He drew a crumpled handkerchief from his hip pocket, shook it out, and wiped his forehead.
"Ah!" exclaimed The Thinking Machine, suddenly.
He had caught the faint, subtle perfume of violets-an odor identical with that on the handkerchief found in front of the safe.
III.
The Thinking Machine led the way back to the private office of the cashier, with President Fraser, Cashier West and Hatch following.
"Is it possible for anyone to overhear us here?" he asked.
"No," replied the president. "The directors meet here."
"Could anyone outside hear that, for instance?" and with a sudden sweep of his hand he upset a heavy chair.
"I don't know," was the astonished reply. "Why?"
The Thinking Machine went quickly to the door, opened it softly and peered out. Then he closed the door again.
"I suppose I may speak with absolute frankness?" he inquired.
"Certainly," responded the old banker, almost startled. "Certainly."
"You have presented an abstract problem," The Thinking Machine went on, "and I presume you want a solution of it, no matter where it hits?"
"Certainly," the president again assured him, but his tone expressed a grave, haunting fear.
"In that case," and The Thinking Machine turned to the reporter, "Mr. Hatch, I want you to ascertain several things for me. First, I want to know if Miss Clarke uses or has ever used violet perfume-if so, when she ceased using it."