"I believe, Mr. Singleton," he said at length, "that you are connected with the Finger-print Department at Scotland Yard?"

"Yes. I am one of the chief a.s.sistants in that department."

"What are your official duties?"

"My princ.i.p.al occupation consists in the examination and comparison of the finger-prints of criminals and suspected persons. These finger-prints are cla.s.sified by me according to their characters and arranged in files for reference."

"I take it that you have examined a great number of finger-prints?"

"I have examined many thousands of finger-prints, and have studied them closely for purposes of identification."

"Kindly examine this paper, Mr. Singleton" (here the fatal leaflet was handed to him by the usher); "have you ever seen it before?"

"Yes. It was handed to me for examination at my office on the tenth of March."

"There is a mark upon it-the print of a finger or thumb. Can you tell us anything about that mark?"

"It is the print of the left thumb of Reuben Hornby, the prisoner at the bar."

"You are quite sure of that?"

"I am quite sure."

"Do you swear that the mark upon that paper was made by the thumb of the prisoner?"

"I do."

"Could it not have been made by the thumb of some other person?"

"No; it is impossible that it could have been made by any other person."

At this moment I felt Juliet lay a trembling hand on mine, and, glancing at her, I saw that she was deathly pale. I took her hand in mine and, pressing it gently, whispered to her, "Have courage; there is nothing unexpected in this."

"Thank you," she whispered in reply, with a faint smile; "I will try; but it is all so horribly unnerving."

"You consider," Sir Hector proceeded, "that the ident.i.ty of this thumb-print admits of no doubt?"

"It admits of no doubt whatever," replied Mr. Singleton.

"Can you explain to us, without being too technical, how you have arrived at such complete certainty?"

"I myself took a print of the prisoner's thumb-having first obtained the prisoner's consent after warning him that the print would be used in evidence against him-and I compared that print with the mark on this paper. The comparison was made with the greatest care and by the most approved method, point by point and detail by detail, and the two prints were found to be identical in every respect.

"Now it has been proved by exact calculations-which calculations I have personally verified--that the chance that the print of a single finger of any given person will be exactly like the print of the same finger of any other given person is as one to sixty-four thousand millions. That is to say that, since the number of the entire human race is about sixteen thousand millions, the chance is about one to four that the print of a single finger of any one person will be identical with that of the same finger of any other member of the human race.

"It has been said by a great authority-and I entirely agree with the statement-that a complete, or nearly complete, accordance between two prints of a single finger affords evidence requiring no corroboration that the persons from whom they were made are the same.

"Now, these calculations apply to the prints of ordinary and normal fingers or thumbs. But the thumb from which these prints were taken is not ordinary or normal. There is upon it a deep but clean linear scar-the scar of an old incised wound-and this scar pa.s.ses across the pattern of the ridges, intersecting the latter at certain places and disturbing their continuity at others. Now this very characteristic scar is an additional feature, having a set of chances of its own. So that we have to consider not only the chance that the print of the prisoner's left thumb should be identical with the print of some other person's left thumb-which is as one to sixty-four thousand millions-but the further chance that these two identical thumb-prints should be traversed by the impression of a scar identical in size and appearance, and intersecting the ridges at exactly the same places and producing failures of continuity in the ridges of exactly the same character. But these two chances, multiplied into one another, yield an ultimate chance of about one to four thousand trillions that the prisoner's left thumb will exactly resemble the print of some other person's thumb, both as to the pattern and the scar which crosses the pattern; in other words such a coincidence is an utter impossibility."

Sir Hector Trumpler took off his gla.s.ses and looked long and steadily at the jury as though he should say, "Come, my friends; what do you think of that?" Then he sat down with a jerk and turned towards Anstey and Thornd.y.k.e with a look of triumph.

"Do you propose to cross-examine the witness?" inquired the judge, seeing that the counsel for the defence made no sign.

"No, my lord," replied Anstey.

Thereupon Sir Hector Trumpler turned once more towards the defending counsel, and his broad, red face was illumined by a smile of deep satisfaction. That smile was reflected on the face of Mr. Singleton as he stepped from the box, and, as I glanced at Thornd.y.k.e, I seemed to detect, for a single instant, on his calm and immovable countenance, the faintest shadow of a smile.

"Herbert John Nash!"

A plump, middle-aged man, of keen, though studious, aspect, stepped into the box, and Sir Hector rose once more.

"You are one of the chief a.s.sistants in the Finger-print Department, I believe, Mr. Nash?"

"I am."

"Have you heard the evidence of the last witness?"

"I have."

"Do you agree with the statements made by that witness?"

"Entirely. I am prepared to swear that the print on the paper found in the safe is that of the left thumb of the prisoner, Reuben Hornby."

"And you are certain that no mistake is possible?"

"I am certain that no mistake is possible."

Again Sir Hector glanced significantly at the jury as he resumed his seat, and again Anstey made no sign beyond the entry of a few notes on the margin of his brief.

"Are you calling any more witnesses?" asked the judge, dipping his pen in the ink.

"No, my lord," replied Sir Hector. "That is our case."

Upon this Anstey rose and, addressing the judge, said-

"I call witnesses, my lord."

The judge nodded and made an entry in his notes while Anstey delivered his brief introductory speech-

"My lord and gentlemen of the jury, I shall not occupy the time of the Court with unnecessary appeals at this stage, but shall proceed to take the evidence of my witnesses without delay."

There was a pause of a minute or more, during which the silence was broken only by the rustle of papers and the squeaking of the judge's quill pen. Juliet turned a white, scared face to me and said in a hushed whisper-

"This is terrible. That last man's evidence is perfectly crushing. What can possibly be said in reply? I am in despair; oh! poor Reuben! He is lost, Dr. Jervis! He hasn't a chance now."

"Do you believe that he is guilty?" I asked.

"Certainly not!" she replied indignantly. "I am as certain of his innocence as ever."