As they walked up and down the terrace their steps and voices were very audible in the stillness of the night; and the windows were lighted in the east wing, showing that the inhabitants were still up there and about. While Jock spoke, one of these windows opened quite suddenly, and for a single moment a figure like a shadow appeared in it. The light movement, sudden as a bird's on the wing, would have betrayed her (she felt) to Jock, even if she had not spoken. But she waved her hand and called out "Good-night" in a voice full of laughter. "Don't talk secrets, for we can hear you," she said. "Good-night!" And so vanished again, with a little echo of laughter from within. The young men were both excited and disconcerted by this interruption. It gave them a sensation of shame for the moment as if they had been caught in a discussion of a forbidden subject; and then a tingling ran through their veins. Even MTutor for the moment found no fine speech in which to express his sense of this sudden momentary tantalising appearance of the mystic woman standing half visible out of the background of the unknown. He did think some very fine things on the subject after a time, with a side glance of philosophical reflection that her light laugh of mockery as she momentarily revealed herself, was an outcome of this sceptical century, and that in a previous age her utterance would have been a song or a sigh. But at the moment even Mr. Derwentwater was subjugated by the thrill of sensation and feeling, and found nothing to say. CHAPTER XXXIV. IN SUSPENSE.