"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.

From the cellar they went to the ground-floor. In the kitchen, kettles and pots were steaming, and the women who were working looked with curiosity at the demeanor of the strangers, for the Doctor kept stamping with his heel on the stone floor, and with his hands sounded the blackened side-wall of the hearth. Behind were store-rooms and the visitors' rooms. In one of these they found a woman in mourning, occupied in arranging the beds. It was the mother from the churchyard. She approached the strangers, and thanked them for having helped to pay the last honors to her child. The friends spoke kindly to her; she wiped her eyes with her apron and returned to her work.

"I begged her to remain at home to-day," said Ilse, "but she would not. It would, she thought, be good for her to have something to do, and we would need her help as you were coming to us."

It pleased our scholars to see that by the female members of the house, at least, they were considered as guests entitled to remain.

They went over the other side of the ground-floor, and once more examined the unpretentious room in which they had been first received. Behind it lay the private room of the proprietor, a small unadorned chamber, in which were a closet with shooting and riding gear, and a shelf for title-deeds and books; over the bed hung a sword and pistols, and on the writing-table there was a small model of a machine, and samples of corn and seeds in small bags; against the wall stood, in military array, gigantic water-boots, Russian leather boots, and top-boots for riding; and in the further corner half-boots of calf skin. In the next room they heard a man's voice, and the answers of children in regular succession.

"That is the school-room," said Ilse, smiling. As the door opened, both solo and chorus stopped. The teacher, a student with an intelligent face, rose to return the greeting of the newcomers. The children stared with astonishment at the unexpected interruption. Three boys and three girls sat at two tables, a vigorous, fair-haired race. "These are Clara, Luise, Rickchen, Hans, Ernest, and Franz."

Clara, a girl of fourteen, almost grown up, and a youthful picture of her sister, rose with a courtesy. Hans, a sturdy boy, twelve years old, made an ineffectual attempt at a bow. The others remained standing straight, staring fixedly at the strangers, and then, as if having sufficiently performed a tiresome duty, dropped down into their places. Only little Franz, a rosy-cheeked, curly-headed urchin, seven years old, remained sitting grimly over his troublesome task, and made use of the interruption quickly to find in his book something for his next answer. Ilse stroked his hair, and asked the tutor, "How is he doing to-day?"