“I called on Mr. Hornby several times and urged him, for the sake of his nephews’ reputations, to sanction the taking of the thumb-prints; but he refused very positively and forbade them to submit, although I understood that they were both willing.  It then occurred to me to try if I could get any help from Mrs. Hornby, and on the fifteenth of March I called at Mr. Hornby’s private house and saw her.  I explained to her what was wanted to clear her nephews from the suspicion that rested on them, and she then said that she could dispose of those suspicions at once, for she could show me the thumb-prints of the whole family:  she had them all in a ‘Thumbograph.’”

“A ’Thumbograph’?” repeated the judge.  “What is a ’Thumbograph’?”

Anstey rose with the little red-covered volume in his hand.

“A ‘Thumbograph,’ my lord,” said he, “is a book, like this, in which foolish people collect the thumb-prints of their more foolish acquaintances.”

He passed the volume up to the judge, who turned over the leaves curiously and then nodded to the witness.

“Yes.  She said she had them all in a ‘Thumbograph.’”

“Then she fetched from a drawer a small red-covered book which she showed to me.  It contained the thumb-prints of all the family and some of her friends.”

“Is this the book?” asked the judge, passing the volume down to the witness.

The sergeant turned over the leaves until he came to one which he apparently recognised, and said—­

“Yes, m’lord; this is the book.  Mrs. Hornby showed me the thumb-prints of various members of the family, and then found those of the two nephews.  I compared them with the photograph that I had with me and discovered that the print of the left thumb of Reuben Hornby was in every respect identical with the thumb-print shown in the photograph.”

“What did you do then?”

“I asked Mrs. Hornby to lend me the ‘Thumbograph’ so that I might show it to the Chief of the Finger-print Department, to which she consented.  I had not intended to tell her of my discovery, but, as I was leaving, Mr. Hornby arrived home, and when he heard of what had taken place, he asked me why I wanted the book, and then I told him.  He was greatly astonished and horrified, and wished me to return the book at once.  He proposed to let the whole matter drop and take the loss of the diamonds on himself; but I pointed out that this was impossible as it would practically amount to compounding a felony.  Seeing that Mrs. Hornby was so distressed at the idea of her book being used in evidence against her nephew, I promised her that I would return it to her if I could obtain a thumb-print in any other way.

“I then took the ‘Thumbograph’ to Scotland Yard and showed it to Mr. Singleton, who agreed that the print of the left thumb of Reuben Hornby was in every respect identical with the thumb-print on the paper found in the safe.  On this I applied for a warrant for the arrest of Reuben Hornby, which I executed on the following morning.  I told the prisoner what I had promised Mrs. Hornby, and he then offered to allow me to take a print of his left thumb so that his aunt’s book should not have to be used in evidence.”