"Jenner was at one time a clerk in the firm of Cass and Marshall," he thought; "therefore he must have known Marshall very well; he was dismissed, and so had no cause to love his employers. Mr. Cass, so far as I know, was always an upright man, and Jenner had no chance of injuring him in any way. With Marshall the case was different. If I remember rightly, Mrs. Jenner told me that her husband and Marshall were as thick as thieves; the master patronising the clerk on account of the man's beautiful voice and musical accomplishments. Marshall, too, lived a gay life, and was given to spending pretty freely. It is quite possible that he might have made use of Jenner as a tool to get more money through this bill! Five hundred pounds," said Geoffrey, looking at the document in question. "Humph! Just the sum he might require for an emergency." He turned over the bill, and found it endorsed by Julius Roper. "Ah!" he went on, "where have I heard that name? Roper--Roper--I am sure someone spoke of Roper." Suddenly it flashed into his mind that Roper was the moneylender in whose employment Jenner had been after he had failed on the stage. "The bill was discounted in the office in which Jenner was employed," he thought, with growing excitement, for the matter was becoming more interesting every minute, "and Jenner, knowing it was forged, stole it from Roper. He meant to use it as a means of extorting blackmail! Ah!" He stopped short. "Blackmail? It was of that he boasted to his wife--this, then, was the material for getting money that he said he had in the red pocket-book. The pocket-book has disappeared; but the bill?--Humph! How did it get inside the horse? Could Jenner himself have put it there? If so, why? What was his reason? I must see Mrs. Jenner and ask her. Between the two of us we may get at the truth." But although he was satisfied that his father's signature had been forged, he could not be absolutely certain that Marshall had been the forger. He had drawn the bill, it was true, but Jenner might have counterfeited the signature and have assisted Marshall to get the money. Then Geoffrey recollected that his father--a particularly precise man--had been in the habit of keeping a diary in which he was accustomed to set down the most trivial details of his somewhat uninteresting life. No sooner had this thought struck him than he went to a certain press and pulled out the series of little books which contained these entries. Glancing at the date of the bill, he set to work, and after an hour's search found the evidence.