"You pulled a tooth for me last night?" went on the prisoner.
"Yes."
"Here?" and the prisoner opened his mouth.
The dentist gazed down him.
"Yes," he replied.
"You may remember, doctor," went on the prisoner, quietly, "that you had occasion to notice the clock just after I called at your house. Do you remember what time it was?"
"A few minutes before two-seven or eight minutes, I think."
Detective Mallory and the Court exchanged bewildered glances.
"You looked at your watch, too. Was that exactly with the clock?"
"Yes, within a minute."
"And what time did I leave your office?" the prisoner asked.
"Seventeen minutes past two-I happen to remember," was the reply.
The prisoner glanced dreamily around the room twice, his eyes met Detective Mallory's. He stared straight into that official for an instant then turned back to the dentist.
"When you drew the tooth there was blood of course. It is possible that I got the stains on my fingers and clothing?"
"Yes, certainly."
The prisoner turned to the Court and surprised a puzzled expression on that official countenance.
"Is anything else necessary?" he inquired courteously. "It has been established that the moment of the crime was two o'clock; I have shown by three witnesses-two of them city officials-that I was two and a half miles away in less than half an hour; I couldn't have gone on a car in less than fifteen minutes-hardly that."
There was a long silence as the Court considered the matter. Finally he delivered himself, briefly.
"It resolves itself into a question of the accuracy of the clocks," he said. "The accuracy of the clock at the Avon is attested by the known accuracy of the clock in the telegraph office, while it seems established that Dr. Sitgreaves' clock was also accurate, because it was with his watch. Of course there is no question of veracity of witnesses-it is merely a question of the clock in Dr. Sitgreaves' office. If that is shown to be absolutely correct we must accept the alibi."
The prisoner turned to the elevator man from the Avon.
"What sort of a clock was that you mentioned?"
"An electric clock, regulated from Washington Observatory," was the reply.
"And the clock at the telegraph office, Mr. Mallory?"
"An electric clock, regulated from Washington Observatory."
"And yours, Dr. Sitgreaves?"
"An electric clock, regulated from Washington Observatory."
The prisoner remained in his cell until seven o'clock that evening while experts tested the three clocks. They were accurate to the second; and it was explained that there could have been no variation of either without this variation showing in the delicate testing apparatus. Therefore it came to pass that Franklin Chase was released on his own recognizance, while Detective Mallory wandered off into the sacred precincts of his private office to hold his head in his hands and think.
Hutchinson Hatch, reporter, had followed the intricacies of the mystery from the discovery of De Forrest's body, through the preliminary hearing, up to and including the expert examination of the clocks, which immediately preceded the release of Franklin Chase. When this point was reached his mental condition was not unlike that of Detective Mallory-he was groping hopelessly, blindly in the mazes of the problem.
It was then that he called to see Professor Augustus S. F. X. Van Dusen-The Thinking Machine. That distinguished gentleman listened to a recital of the known facts with petulant, drooping mouth and the everlasting squint in his blue eyes. As the reporter talked on, corrugations appeared in the logician's expansive brow, and these gave way in turn to a net-work of wrinkles. At the end The Thinking Machine sat twiddling his long fingers and staring upward.
"This is one of the most remarkable cases that has come to my attention," he said at last, "because it possesses the unusual quality of being perfect in each way-that is the evidence against Mr. Chase is perfect and the alibi he offers is perfect. But we know instantly that if Mr. Chase killed Mr. De Forrest there was something the matter with the clocks despite expert opinion.
"We know that as certainly as we know that two and two make four, not some times but all the time, because our reason tells us that Mr. Chase was not in two places at once at two o'clock. Therefore we must assume either one of two things-that something was the matter with the clocks-and if there was we must assume that Mr. Chase was responsible for it-or that Mr. Chase had nothing whatever to do with Mr. De Forrest's death, at least personally."
The last word aroused Hatch to a new and sudden interest. It suggested a line of thought which had not yet occurred to him.
"Now," continued the scientist, "if we can find one flaw in Mr. Chase's story we will have achieved the privilege of temporarily setting aside his defence and starting over. If, on the contrary, he told the full and exact truth and our investigation proves that he did, it instantly clears him. Now just what have you done, please?"
"I talked to Dr. Sitgreaves," replied Hatch. "He did not know Chase-never saw him until he pulled the tooth, and then didn't know his name. But he told me really more than appeared in court, for instance, that his watch had been regulated only a few days ago, that it had been accurate since, and that he knew it was accurate next day because he kept an important engagement. That being accurate the clock must be accurate, because they were together almost to the second.
"I also talked to every other person whose name appears in the case. I questioned them as to all sorts of possibilities, and the result was that I was compelled to accept the alibi-not that I'm unwilling to of course, but it seems peculiar that De Forrest should have written the name as he was dying."
"You talked to the young men who went into Mr. Chase's room at two o'clock?" inquired The Thinking Machine casually.
"Yes."
"Did you ask either of them the condition of Mr. Chase's bed when they went in?"
"Yes," replied the reporter. "I see what you mean. They agreed that it was tumbled as if someone had been in it."
The Thinking Machine raised his eyebrows slightly.
"Suppose, Mr. Hatch, that you had a violent toothache," he asked after a moment, still casually, "and were looking for relief, would you stop to notice the number of a policeman who told you where there was a dentist's office?"
Hatch considered it calmly, as he stared into the inscrutable face of the scientist.
"Oh, I see," he said at last. "No, I hardly think so, and yet I might."
Later Hatch and The Thinking Machine, by permission of Detective Mallory, made an exhaustive search of De Forrest's apartments in the Avon, seeking some clue. When the Thinking Machine went down the single flight of stairs to the office he seemed deeply perplexed.
"Where is your clock?" he inquired of the elevator man.
"In the inside office, opposite the telephone booth," was the reply.
The scientist went in and taking a stool, clambered up and squinted fiercely into the very face of the timepiece. He said "Ah!" once, non-commitally, then clambered down.
"It would not be possible for anyone here to see a person pass through the hall," he mused. "Now," and he picked up a telephone book, "just a word with Dr. Sitgreaves."
He asked the dentist only two questions and their nature caused Hatch to smile. The first was: