The most that William could do was to stand at the head of the stairs and say good-night.

He could not offer to go with them.

He could not insist that she should stay.

He watched her descend, rather slowly, owing to the dusk of the staircase, and he had a last sight of Denham's head and of Katharine's head near together, against the panels, when suddenly a pang of acute jealousy overcame him, and had he not remained conscious of the slippers upon his feet, he would have run after them or cried out.

As it was he could not move from the spot.