“Do—and load it—in all six chambers—I suppose you haven’t brought any ‘blanks’?” Peter shook his head. “Sorry—I haven’t!” “H’m,” muttered Anthony, “never mind. We shall have to take care—that’s all!” It was the work of a few moments that brought Peter back to the library with his revolver. “Now listen,” directed Anthony, “I want you to fire two separate shots—you’ll have to fire of course out into the garden—fire in the direction of the fountain, for instance—that will do—make sure there’s nobody about—stand in the center of the room when you fire.” He walked to the library door. “Where are you going?” questioned Peter. “Aren’t you going to stop to enjoy the performance?” “I’m going to shut this door, which I want you to _keep_ shut—then I’m going upstairs to my own bedroom—look at your watch—in five minutes’ time fire one shot—then wait till you hear from me—clear on everything?” “Right‑o,” murmured Peter. “I understand perfectly.” Anthony closed the door. Peter watched the hand of his watch travel the five appointed minutes. Then he walked to the French doors and opened them. The coast was clear—the walk to the rockery entirely deserted. He returned to the center of the room as he had been directed and pulled the trigger. Then he grinned to himself. “Expect the inhabitants of Assynton Lodge that hear that will be scared stiff unless old Bathurst tipped them the bright idea just now.” The door opened behind him. “Well?” said Bathurst. “Well?” said Peter. “I lay on my bed just as I should if I were there in the ordinary way, and although I was _listening_, old son, _I never heard a sound_.” His face showed obvious signs of pleasure. “What makes you so pleased about that?” queried Peter. “What makes me pleased?” echoed Anthony. “Why, it fits in with my theory beautifully—that’s what pleases me. Now I’m going again—wait another five minutes and then fire a second shot exactly similar to the previous one.” He slipped out again noiselessly. Peter waited patiently for the second spell of five minutes to pass. Taking care again that all was in order in the garden, he walked back to the center of the library as before and for the second time discharged his revolver. “Where did that one go to?” he murmured reminiscently—then sat on the table till the arrival of Bathurst. “Just the same as before,” announced the latter. “I took the liberty of using Charles Stewart’s bedroom for that little experiment—it’s on the floor below ours, you know—I asked him if I might just now—and once again, Daventry, _I heard nothing at all_.” He thrust his hands into his pockets and walked to the bookcase. “That experiment that we have just conducted,” he continued, “proves to me conclusively that the shot that we know had _at some time_ been fired from Stewart’s revolver _had been fired by him on the night of the murder_, but why—why?” He paced backwards and forwards three or four times.