Sir Clinton laughed, though not sneeringly.
“Would you lend me one of your shoes for a moment, madame?” he asked. “You can lean on me while it's off, so as not to put your foot on the wet sand.”
Mme. Laurent-Desrousseaux slipped off her right shoe and held it out.
“Now, inspector, there's absolutely no deception. Look at the number stamped on it. A four, isn't it?”
Armadale examined the shoe, and nodded affirmatively.
“Now take the shoe and press it gently on the sand alongside a right-foot print of Mme. Laurent-Desrousseaux—that one there will do. See that you get it square on the sand and make a good impression.”
The inspector knelt down and did as he was told. As he lifted the shoe again, Wendover saw a look of astonishment on his face.
“Why, they don't correspond!” he exclaimed. “The one I've made just now is bigger than the other.”
“Of course,” the chief constable agreed. “Now do you see that a No. 4 shoe can make an impression smaller than itself if you happen to be walking in sand or mud? While you were hunting for people with 3½ shoes, I was turning my attention to No. 4's. There aren't so many in the hotel, as you know. And it so happened that I began with Mme. Laurent-Desrousseaux. She was good enough to go for a walk with me; and by counting her steps I gauged the length of her pace. It corresponded to the distance on the tracks.”
Mme. Laurent-Desrousseaux was examining Sir Clinton with obvious admiration, not wholly unmixed with a certain uneasiness.