Mr. Undercliff went to a set of drawers arranged chronologically, and found his notes directly. "It was a forged bill, madam, indorsed and presented by Penfold. I was called to prove that the bill was not in the handwriting of Penfold. Here is my fac-simile of the Robert Penfold indorsed upon the bill by the prisoner." He handed it her, and she examined it with interest. "And here are fac-similes of genuine writing by John Wardlaw; and here is a copy of the forged note." He laid it on the table before her. She started, and eyed it with horror. It was a long time before she could speak. At length she said, "And that wicked piece of paper destroyed Robert Penfold." "Not that piece of paper, but the original; this is a fac-simile, so far as the writing is concerned. It was not necessary in this case to imitate paper and color. Stay, here is a sheet on which I have lithographed the three styles; that will enable you to follow my comparison. But perhaps that would not interest you." Helen had the tact to say it would. Thus encouraged, the expert showed her that Robert Penfold's writing had nothing in common with the forged note. He added: "I also detected in the forged note habits which were entirely absent from the true writing of John Wardlaw. You will understand there were plenty of undoubted specimens in court to go by." "Then, oh, sir," said Helen, "Robert Penfold was not guilty." "Certainly not of writing the forged note. I swore that, and I'll swear it again. But when it came to questions whether he had passed the note, and whether he knew it was forged, that was quite out of my province." "I can understand that," said Helen; "but you heard the trial; you are very intelligent, sir, you must have formed some opinion as to whether he was guilty or not." The expert shook his head. "Madam," said he, "mine is a profound and difficult art, which aims at certainties. Very early in my career I found that to master that art I must be single-minded, and not allow my ear to influence my eye. By purposely avoiding all reasoning from external circumstances, I have distanced my competitors in expertise; but I sometimes think I have rather weakened my powers of conjecture through disuse. Now, if my mother had been at the trial, she would give you an opinion of some value on the outside facts. But that is not my line. If you feel sure he was innocent, and want me to aid you, you must get hold of the handwriting of every person who was likely to know old Wardlaw's handwriting, and so might have imitated it; all the clerks in his office, to begin with. Nail the forger; that is your only chance." "What, sir!" said Helen, with surprise, "if you saw the true handwriting of the person who wrote that forged note, should you recognize it?" "Why not? It is difficult; but I have done it hundreds of times." "Oh! Is forgery so common?"