"It was, sir, and I don't know that I was ever more nonplussed. There's nothing curious in her being in Catchpole Square. She might have slipped in there to sleep the night out, not having money enough to pay for a bed. Pond and me happened to meet on the boundary of our beats, and we strolled into the Square. I could have swore that she was creeping along the wall; perhaps she was scared at the sight of us, and had a reason for not wanting to fall in the hands of the law." "That will hardly hold water," said Dick. "She could have had no clearer a sight of you than you had of her. There have been too many bad deeds committed in dark places in the dead of the night, and seeing something moving that she couldn't account for, she was frightened and ran away. Did you call out to her?" "I did. 'Now, then,' I cried, 'what are you up to?' Not a word did she answer. Then I caught hold of her; then she vanished. Which goes to prove," said Constable Applebee, contemplatively, "that she wasn't one of the regular ones. If she'd been a regular one she'd have cheeked us. Not being a regular one, what business did she have there? Anyway Catchpole Square ain't exactly the place _I_ would choose for a night's lodging." "Beggars can't be choosers," remarked Dick. "Right you are, sir. They can't." The conversation slackened, and the men walked slowly along Shore Street, the constable, like a zealous officer, trying the doors and looking up at the windows. "The people inside," he said, "are better off than we are. They're snugly tucked up between the sheets, dreaming of pleasanter things than tramping a thick fog." "There's somebody there," said Dick, pointing to a first floor window, where, through the mist, a light could be dimly seen, "who isn't between the sheets. See how the light shifts, like a will-o'-the-wisp." "That's Dr. Pye's house, where the midnight oil is always burning. Yes, he's awake, the doctor; it's my belief he never sleeps. A clever gentleman, Dr. Pye, as chockful of science as an egg is of meat. Do you happen to be acquainted with him, sir?" "No." "A strange character, sir. The things they tell of him is beyond belief. I've heard say that he's discovered the secret of prolonging life, and of making an old man young." "But you haven't heard that he has ever done it." "No, or I might have asked him what his charge was for taking ten or twenty years off. Perhaps it's as well, though, to fight shy of that sort of thing. What they say of Dr. Pye may be true, or it mayn't, but you may make sure that he's always at his experiments. Pass his house at any hour of the night you like, and you may depend upon seeing that light burning in his window."