A dance was going on in the ball-room, and the hall at the moment was empty, save for himself. He paused before a huge mirror, which had been raised at one end of it, and in front of which was erected a fragrant pyramid of flowers and ferns, delicate hothouse blossoms, and feathery aromatic leaves. There was a blaze of light all around, and the staircase and part of the gallery running round the second story were reflected in the mirror. Sebastian stood before the pyramid of flowers, and gently first touched one and then the other, and then his eyes fell upon the reflection of his own face, and he was surprised to see how grave it looked; for he did not feel particularly grave at the moment, and that interview with Adrienne Blisset seemed to hang like a dream in the far background of his consciousness, while another face and form, flower-crowned and glowingly beautiful, advanced to the front. Suddenly he became conscious, as it were, of some shadow crossing the glass, and looking higher, to where the staircase was reflected, he saw the figure of a man stealing carefully, softly, noiselessly up the stairs, keeping well to the wall, with averted face, as if anxious to get as quickly as possible out of all that obtrusive glare of light and stream of dancing sound. CHAPTER XVII. HOW MR. SPENCELEY MET HIS DIFFICULTIES. Sebastian’s first thought naturally resolved itself into the words, ‘A thief in the night;’ some evil-disposed person who thought to penetrate to some of the bedrooms, in the confusion, and perhaps reap a harvest of neglected brooches, watches, or shawl-pins. In such a case, it was his duty at once to warn the servants, and he was in the act of turning to go and do so as quickly as possible, when the figure reached the head of the first flight of stairs, and turned to mount the next. As this happened, Sebastian caught a momentary glimpse of the face. He was long sighted, and not given to making mistakes in the matter of identity. The man who was stealing so quietly up the stairs in such evident fear of detection was, one would suppose, the last person who should need to act in so strange a manner. It was Mr. Spenceley himself, the master of the house. With great presence of mind Sebastian checked his movement to turn round, and neither started nor stirred, but stood pensively trifling with a fern leaf, as he gave himself time to reflect upon what had happened.