"The house may be considered remarkable by strangers," said Ilse; "we like it because it is warm and roomy; and when my father had been some years in possession of the estate, and had the means to do so, he had the house comfortably arranged to please my deceased mother. We require plenty of room, as I have six younger brothers and sisters, and it is a large estate. The overseers of the farm eat with us; then there are the tutor and Mamselle, and in the servants' hall there are also twenty people." The Doctor regarded his neighbor with a look of disappointment. What had become of the Sibyl? She spoke sensibly and very much like a citizen; with her something might be accomplished. "A$ we are searching for hollow spaces," he began slyly, "we would rather trust to your guidance, if you would tell us whether there are any places in the wall, or on the ground, or anywhere here in the house, that you know of, which could be discovered by knocking?" "O, there are plenty of such places!" answered Ilse. "If one knocks upon the wall at the back of the small cupboard in my room, it is evident there is an empty space behind; then there is the flagstone under the stairs, and many flags in the kitchen, and still more in other parts of the house, regarding which every one has his conjectures." The Doctor had taken out his memorandum-book and noted the suspicious places. The inspection of the house began. It was a fine old building; the walls of the lower story were so thick that the Doctor with extended arms could not span the depths of the window-niches. He eagerly undertook the sounding, and began measuring the walls. The cellars were partly hewn in the rock. In some places the rough stone still projected, and one could perceive where the wall rested on the rock. There were vast vaults, the small windows in the top of which were protected by strong iron bars,--in ancient times a secure refuge against the shot and assault of the enemy. All was dry and hollow, for the house was built, as the Doctor had already before so acutely suggested in speaking of old buildings, with outer and inner walls, and filled between with rubbish and broken stones. Naturally, therefore, the walls in many places sounded as hollow as a gourd. The Doctor knocked, and diligently took note. The knuckles of his hand became white and swelled, and the number of good places discouraged him.