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."

"How is it, then," asked the judge, "that it has been put in evidence?"

"It has been put in by the defence, my lord," said Sir Hector Trumpler.

"I see," said the judge. "'A hair of the dog that bit him.' The 'Thumbograph' is to be applied as a remedy on the principle that similia similibus curantur. Well?"

"When I arrested him, I administered the usual caution, and the prisoner then said, 'I am innocent. I know nothing about the robbery.'"

The counsel for the prosecution sat down, and Anstey rose to cross-examine.

"You have told us," said he, in his clear musical voice, "that you found at the bottom of the safe two rather large drops of a dark fluid which you considered to be blood. Now, what led you to believe that fluid to be blood?"

"I took some of the fluid up on a piece of white paper, and it had the appearance and colour of blood."

"Was it examined microscopically or otherwise?"

"Not to my knowledge."

"Was it quite liquid?"

"Yes, I should say quite liquid."

"What appearance had it on paper?"

"It looked like a clear red liquid of the colour of blood, and was rather thick and sticky."

Anstey sat down, and the next witness, an elderly man, answering to the name of Francis Simmons, was called.

"You are the housekeeper at Mr. Hornby's premises in St. Mary Axe?" asked Sir Hector Trumpler.

"I am."

"Did you notice anything unusual on the night of the ninth of March?"

"I did not."

"Did you make your usual rounds on that occasion?"

"Yes. I went all over the premises several times during the night, and the rest of the time I was in a room over the private office."

"Who arrived first on the morning of the tenth?"

"Mr. Reuben. He arrived about twenty minutes before anybody else."

"What part of the building did he go to?"

"He went into the private office, which I opened for him. He remained there until a few minutes before Mr. Hornby arrived, when he went up to the laboratory."

"Who came next?"

"Mr. Hornby, and Mr. Walter came in just after him."

The counsel sat down, and Anstey proceeded to cross-examine the witness.

"Who was the last to leave the premises on the evening of the ninth?"

"I am not sure."

"Why are you not sure?"

"I had to take a note and a parcel to a firm in Sh.o.r.editch. When I started, a clerk named Thomas Holker was in the outer office and Mr. Walter Hornby was in the private office. When I returned they had both gone."

"Was the outer door locked?"

"Yes."

"Had Holker a key of the outer door?"

"No. Mr. Hornby and his two nephews had each a key, and I have one. No one else had a key."

"How long were you absent?"

"About three-quarters of an hour."

"Who gave you the note and the parcel?"

"Mr. Walter Hornby."

"When did he give them to you?"

"He gave them to me just before I started, and told me to go at once for fear the place should be closed before I got there."

"And was the place closed?"

"Yes. It was all shut up, and everybody had gone."

Anstey resumed his seat, the witness shuffled out of the box with an air of evident relief, and the usher called out, "Henry James Singleton."

Mr. Singleton rose from his seat at the table by the solicitors for the prosecution and entered the box. Sir Hector adjusted his gla.s.ses, turned over a page of his brief, and cast a steady and impressive glance at the jury.