“Thank you, that is quite clear,” said the judge, with a smile of deep content, such as is apt to appear on the judicial countenance when an expert witness is knocked off his pedestal. “We may now proceed, Mr. Anstey.”
“You have told us,” resumed Anstey, “and have submitted proofs, that it is possible to forge a thumbprint so that detection is impossible. You have also stated that the thumbprint on the paper found in Mr. Hornby’s safe is a forgery. Do you mean that it may be a forgery, or that it actually is one?”
“I mean that it actually is a forgery.”
“When did you first come to the conclusion that it was a forgery?”
“When I saw it at Scotland Yard. There are three facts which suggested this conclusion. In the first place the print was obviously produced with liquid blood, and yet it was a beautifully clear and distinct impression. But such an impression could not be produced with liquid blood without the use of a slab and roller, even if great care were used, and still less could it have been produced by an accidental smear.
“In the second place, on measuring the print with a micrometer, I found that it did not agree in dimensions with a genuine thumbprint of Reuben Hornby. It was appreciably larger. I photographed the print with the micrometer in contact and on comparing this with a genuine thumbprint, also photographed with the same micrometer in contact, I found that the suspected print was larger by the fortieth of an inch, from one given point on the ridge-pattern to another given point. I have here enlargements of the two photographs in which the disagreement in size is clearly shown by the lines of the micrometer. I have also the micrometer itself and a portable microscope, if the Court wishes to verify the photographs.”
“Thank you,” said the judge, with a bland smile; “we will accept your sworn testimony unless the learned counsel for the prosecution demands verification.”
He received the photographs which Thorndyke handed up and, having examined them with close attention, passed them on to the jury.
“The third fact,” resumed Thorndyke, “is of much more importance, since it not only proves the print to be a forgery, but also furnishes a very distinct clue to the origin of the forgery, and so to the identity of the forger.” (Here the court became hushed until the silence was so profound that the ticking of the clock seemed a sensible interruption. I glanced at Walter, who sat motionless and rigid at the end of the bench, and perceived that a horrible pallor had spread over his face, while his forehead was covered with beads of perspiration.) “On looking at the print closely, I noticed at one part a minute white mark or space. It was of the shape of a capital S and had evidently been produced by a defect in the paper—a loose fibre which had stuck to the thumb and been detached by it from the paper, leaving a blank space where it had been. But, on examining the paper under a low power of the microscope, I found the surface to be perfect and intact. No loose fibre had been detached from it, for if it had, the broken end or, at least, the groove in which it had lain, would have been visible. The inference seemed to be that the loose fibre had existed, not in the paper which was found in the safe, but in the paper on which the original thumbmark had been made. Now, as far as I knew, there was only one undoubted thumbprint of Reuben Hornby’s in existence—the one in the ‘Thumbograph.’ At my request, the ‘Thumbograph’ was brought to my chambers by Mrs. Hornby, and, on examining the print of Reuben Hornby’s left thumb, I perceived on it a minute, S-shaped white space occupying a similar position to that in the red thumbmark; and when I looked at it through a powerful lens, I could clearly see the little groove in the paper in which the fibre had lain and from which it had been lifted by the inked thumb. I subsequently made a systematic comparison of the marks in the two thumbprints; I found that the dimensions of the mark were proportionally the same in each—that is to say, the mark in the ‘Thumbograph’ print had an extreme length of 26/1000 of an inch and an extreme breadth of 14.5/1000 of an inch, while that in the red thumbmark was one-fortieth larger in each dimension, having an extreme length of 26.65/1000 of an inch and an extreme breadth of 14.86/1000 of an inch; that the shape was identical, as was shown by superimposing tracings of greatly enlarged photographs of each mark on similar enlargements of the other; and that the mark intersected the ridges of the thumbprint in the same manner and at exactly the same parts in the two prints.”
“Do you say that—having regard to the facts which you have stated—it is certain that the red thumbmark is a forgery?”
“I do; and I also say that it is certain that the forgery was executed by means of the ‘Thumbograph.’ ”
“Might not the resemblances be merely a coincidence?”
“No. By the law of probabilities which Mr. Singleton explained so clearly in his evidence, the adverse chances would run into untold millions. Here are two thumbprints made
