She fixed her suspicious eyes upon him expectantly. “Didn’t forget to turn off the gas when you went out, did you? If I was Shylock Holmes, maybe I’d tell from the stain on your glove that you didn’t.” “What do you mean about gas? I never use the cooker.” “Somebody does, and he nearly cooked me and a friend of mine—nearly cooked us good!” He saw her frown. Since she was a woman he expected her to be an actress, but somehow he was ready to believe in her sincerity. “There’s been a gas attack on Caverley House,” he explained, “and not cooking gas either. I guess you’ll smell it as you go up.” “What kind of gas—poison?” Elk nodded. “But who put it there—emptied it, or whatever is done with gas?” Elk looked at her with that wounded expression which so justly irritated his victims. “If I knew, Lola, would I be standing here discussing the matter? Maybe my old friend Shylock Holmes would, but I wouldn’t. I don’t know. It was upset in Mr. Broad’s flat.” “That is the American who lives opposite to us—to me,” she said. “I’ve only seen him once. He seems a nice man.” “Somebody didn’t think so,” said Elk. “I say, Lola, what’s that boy doing—young Bennett?” “Why do you ask me? He is making a lot of money just now, and I suppose he is running a little wild. They all do.” “I didn’t,” said Elk; “but if I’d made money and started something, I’d have chosen a better pacemaker than a dud fighting man.” The angry colour rose to her pretty face, and the glance she shot at him was as venomous as the gas he had fought all night. “And I think I’d have put through a few enquiries to central office about my female acquaintances,” Elk went on remorselessly. “I can understand why you’re glued to the game, because money naturally attracts you. But what gets me is where the money comes from.” “That won’t be the only thing that will get you,” she said between her teeth as she flounced into the half-opened door of Caverley House. Elk stood where she had left him, his melancholy face expressionless. For five minutes he stood so, and then walked slowly in the direction of his modest bachelor home. He lived over a lock-up shop, a cigar store, and he was the sole occupant of the building. As he crossed Gray’s Inn Road, he glanced idly up at the windows of his rooms and noted that they were closed. He noticed something more. Every pane of glass was misty with some yellow, opalescent substance. Elk looked up and down the silent street, and at a short distance away saw where road repairers had been at work. The night watchman dozed before his fire, and did not hear Elk’s approach or remark his unusual action. The detective found in a heap of gravel, three rounded pebbles, and these he took back with him. Standing in the centre of the road, he threw one of the pebbles unerringly. There was a crash of glass as the window splintered. Elk waited, and presently he saw a yellow wraith of poison-vapour curl out and downward through the broken pane.