Still kneeling upon the floor he bent forward and threw all his weight and strength upon some lever, with the result that there came a long, whirling, grinding noise, ending once more in a powerful click. He straightened himself then, and I saw that what he held in his hand was a sort of gun, with a curiously misshapen butt. He opened it at the breech, put something in, and snapped the breech-lock. Then, crouching down, he rested the end of the barrel upon the ledge of the open window, and I saw his long moustache droop over the stock and his eye gleam as it peered along the sights. I heard a little sigh of satisfaction as he cuddled the butt into his shoulder; and saw that amazing target, the black man on the yellow ground, standing clear at the end of his foresight. For an instant he was rigid and motionless. Then his finger tightened on the trigger. There was a strange, loud whiz and a long, silvery tinkle of broken glass. At that instant Holmes sprang like a tiger on to the marksman’s back, and hurled him flat upon his face. He was up again in a moment, and with convulsive strength he seized Holmes by the throat, but I struck him on the head with the butt of my revolver, and he dropped again upon the floor. I fell upon him, and as I held him my comrade blew a shrill call upon a whistle. There was the clatter of running feet upon the pavement, and two policemen in uniform, with one plain-clothes detective, rushed through the front entrance and into the room.