Walking on the south side of Oxford-St. eastward, he stopped to look at some books behind a grille. The moonshine was so luminous, the sky so clear, that he could see well enough to read their titles. This was the only quiet hour of London. There was not a sound, save the echo of a policeman's tread some way off down Regent-St. Not even a night cab rattled in the distance. And then, on the other side of the street, his quick ears caught the passing of swift-gliding feet--a woman's. When David glanced round, already she was gone well past him, making westward, most silently, with a steady haste. She gave him the impression of having been overtaken by, of being shy at, the moonlight. His heart leaped in a spasm of recognition, almost of fear. And he followed, he could not help it; as water flows downward, as the needle follows the magnet, he followed, with the stealthy pace of the stalker, as silently as if he was tracking a deer, and as keenly. His breathing, meantime, was as if suspended, his heart seemed to stand still. That form and motion, his instincts would have recognized them in midnight glimmer of dull lamps, and now they were before him in light. Still he could not believe his wits. He doubted whether he was not moonstruck, chasing a phantom made of the clair-obscure stuff of those dead hours of the night when dreams are rife in the world, and ghosts leer through the haunted chambers of the brain. That _she_ should be walking the streets of London at three in the morning, alone, hastening secretly homeward like some poor outcast foreconscious of the light of dawn!--this savored somewhat of limbo and lunacy. For what good reason could she be thus abroad? A swarm of doubts, half-doubts, queer bodings, jostled in David's heart. She might, indeed, have come out to summon a doctor, to obtain a drug in an emergency. But something in her air and pace, something clandestine, desperate, illicit, seemed to belie this hope. She turned north when she had gone so far west as Orchard-St., little thinking, apparently, that she was being shadowed, and thence sped on west and north alternately through smaller streets, a region in which the desolation of the sleeping city seemed even more confirmed. And David followed, with this thought in his mind, that, though he had not seen her face, he had a certain means of determining her identity--for, if the flying figure before him went to 60A, Porchester Gardens, the address which he had of Violet Mordaunt, then this must be Violet.