“I’m putting a hypothetical case, remember,” Sir Clinton cautioned him. “This is what might be said—I don’t necessarily accept it myself. I’m only trying to show you how it could be made to look, you understand? Well, then, this secretary, Richard Roe, sooner or later sees the chance which Providence has thrown in his way. His employer is in the habit of drawing bearer cheques for large amounts—some thousands—from time to time. And, rather carelessly, he has dropped into the way of getting his secretary to cash them for him and bring him the money. So the bank is accustomed to paying over these things to the secretary, and no questions asked.” Stenness gave no sign of special interest. His normal reserve was sufficient to veil his thoughts. “The secretary, we may assume, is an acute fellow. I think we may take it that he may see a chance when it comes his way. But forgery requires a certain amount of manual skill if it is carried out in some ways; and possibly the secretary is sufficiently acute to distrust his powers as a forger. But it’s always possible to trace a signature.” Sir Clinton pulled out his cigarette case and lit a cigarette before going on. He seemed determined to infuse informality into the proceedings. “It’s always possible to trace a signature,” he continued. “But one needs a model signature for that—a signature from a cheque, of course, because sensible people don’t use their letter signature on their cheques. They have a special one with some specific trick in it—the position of a dot, or something of the sort. I hope I’m not boring you with these elementary things.” “Not at all,” said Stenness, with a certain show of polite interest. “The model, in the case of the secretary Richard Roe,” went on Sir Clinton, “could easily be chosen from one of the old cheques returned by the bank. He had access to these, we may suppose. But then comes in a point which is sure to strike his acute mind. A man never writes his signature twice in precisely the same way; there’s always a faint difference between any two signatures. Hence, if two cheques turn up with identical signatures, a sharp detective might suspect something wrong. You follow me?” Stenness nodded in silence. “The acute secretary, Richard Roe, therefore traces his employer’s signature from one of these old cheques. And to cover his trail, to make certain that the thing cannot be shown to be a traced signature, he then destroys the old cheque. Thus there are not two identical signatures in existence; and the only thing missing is a cancelled cheque—not a thing anyone is likely to make a fuss about at the worst, even if its disappearance is noted. I make myself clear?” “Quite,” said Stenness, still with his air of formal interest.