Wimsey glanced round the circle.
"I think," he said, "I had better begin from the beginning by explaining to you the mechanism of my safe. It is rather a nice safe," he added plaintively. "I invented the idea myself—not the principle of its working, of course; that is a matter for scientists—but just the idea of the thing.
"The combination I gave you is perfectly correct as far as it goes. It is a three-alphabet thirteen-letter lock by Bunn & Fishett—a very good one of its kind. It opens the outer door, leading into the ordinary strong-room, where I keep my cash and my Froth Blower's cuff-links and all that. But there is an inner compartment with two doors, which open in quite a different manner. The outermost of these two inner doors is merely a thin steel skin, painted to look like the back of the safe and fitting closely, so as not to betray any join. It lies in the same plane as the wall of the room, you understand, so that if you were to measure the outside and the inside of the safe you would discover no discrepancy. It opens outwards with an ordinary key, and, as I truly assured the President, it was left open when I quitted my flat."
"Do you think," said the woman sneeringly, "that the President is so simple as to be caught in a so obvious trap? He will have wedged open that inner door undoubtedly."
"Undoubtedly, madame. But the sole purpose of that outer inner door, if I may so express myself, is to appear to be the only inner door. But hidden behind the hinge of that door is another door, a sliding panel, set so closely in the thickness of the wall that you would hardly see it unless you knew it was there. This door was also left open. Our revered Number One had nothing to do but to walk straight through into the inner compartment of the safe, which, by the way, is built into the chimney of the old basement kitchen, which runs up the house at that point. I hope I make myself clear?"
"Yes, yes—get on. Make your story short."
Wimsey bowed, and, speaking with even greater deliberation than ever, resumed:
"Now, this interesting list of the Society's activities, which I have had the honour of compiling, is written in a very large book—bigger, even, than Monsieur le Président's ledger which he uses downstairs. (I trust, by the way, madame, that you have borne in mind the necessity of putting that ledger in a safe place. Apart from the risk of investigation by some officious policeman, it would be inadvisable that any junior member of the Society should get hold of it. The feeling of the meeting would, I fancy, be opposed to such an occurrence.)"
"It is secure," she answered hastily. "Mon dieu! get on with your story."
"Thank you—you have relieved my mind. Very good. This big book lies on a steel shelf at the back of the inner compartment. Just a moment. I have not described this inner compartment to you. It is six feet high, three feet wide, and three feet deep. One can stand up in it quite comfortably, unless one is very tall. It suits me nicely—as you may see, I am not more than five feet eight and a half. The President has the advantage of me in height; he might be a little cramped, but there would be room for him to squat if he grew tired of standing. By the way, I don't know if you know it, but you have tied me up rather tightly."