But Gilbert had no doubts, and in the end Williamson received a note saying that after that week his services would not be required. At the same time, the head-clerk was given a handsome cheque as a solatium. Gilbert next set out for the office of Roscoe and Martin, where he was fortunate to find Archer Martin. As briefly as possible, Gilbert told him that he had reason to believe there had been some irregularities in his father's office, and that his father had deputed him to invite the accountant to make a searching investigation immediately, if that fitted in with his engagements. "As it happens, it does; I can set to work to-morrow," said Martin. "Of course," said Gilbert, "it is a confidential investigation--that is understood." "Certainly," said the accountant, who had no idea that he might innocently be making himself a party to a fraud. Archer Martin, accordingly, went to 176, New Square, the following day, and began his inquiries. Without referring to any one except Gilbert, he went on his way, steadily plodding through the books and papers of the firm. His labours extended over several days, but he had not gone very far when he saw the true character of the work he was engaged on. He knew there was being disclosed bit by bit a gigantic system of fraud which involved huge sums of money, and that the system had been practised remorselessly and with diabolical cunning and ingenuity for years. He saw that Cooper Silwood, by one means or another, had appropriated many thousands of pounds, though what he had done with the cash did not appear. It was plain he had stopped at nothing; there were false entries everywhere and many forgeries. He wondered at the ability Silwood had manifested in keeping up appearances so long. It was evident to him, from various sums of interest being paid to clients at the proper time, as if their investments still remained, that Silwood had kept a strict account of his robberies, but though he searched in Silwood's room, throughout the rest of the office, and even in Silwood's apartments in Stone Buildings, for some book or memoranda relating to these robberies, he could not find it. He came to the conclusion that Silwood had either destroyed it or taken it with him. He had heard of Silwood's death as well as of the death of Morris Thornton, and now saw pretty clearly how matters stood. Failing to light upon Silwood's memoranda, he tried to see what could be done by tracking out some of the larger transactions of the defaulting solicitor, which necessarily involved the names of other persons. And this led him to make an extraordinary discovery, though he did not think it so extraordinary as it really was.